Ординатура / Офтальмология / Учебные материалы / Clinical Diagnosis and Management of ocular trauma
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Clinical Diagnosis and Management of Ocular Trauma |
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TRAUMATIC WOUND DEHISCENCE |
ruptures were associated with increased rates of retinal |
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FOLLOWING PENETRATING KERATOPLASTY |
detachments, phthisis, and enucleation, contributing |
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Penetrating keratoplasty requires long-term follow-up. |
to the poorer visual prognosis in these patients. |
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Major potential complications include graft reaction, |
Although extremely rare systemic complication of |
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suture related problems, infective keratitis, recurrence |
venous air embolism has been reported during repair |
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of disease and cataract. Wound dehiscence is a rare |
of penetrating injury in a child. |
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complication occurring in an otherwise normal graft. |
TRAUMATIC CATARACT |
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Traumatic wound dehiscence may occur any time after |
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penetrating keratoplasty. Cases of traumatic wound |
Significant open globe injury is frequently associated |
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dehiscence have been reported many years after |
with development of cataract. Details of management |
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successful keratoplasty. In various series incidence |
options will be discussed in a separate chapter. |
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ranging from 1.3 to 2.5% has been reported. Young |
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male patients are most often affected. |
CORNEAL INFECTION |
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Keratoconus, pseudophakic corneal edema, graft |
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During examination and surgery patient should be |
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failure, endothelial dystrophy and viral keratitis have |
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specifically looked for presence of any infiltrate. Patient |
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been reported as indications of keratoplasty in cases |
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with history of injury with dental wires may get |
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of wound dehiscence. The indication of the original |
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polymicrobial keratitis. Patient suffering corneal injury |
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graft is not thought to influence the risk wound |
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with wooden splinter or with retained intracorneal |
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dehiscence. Grafts on avascular corneas heal without |
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wooden foreign bodies may develop fungal infection. |
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vascularization. The vascularization of the corneal |
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Corneal foreign body should be removed on |
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wound strengthen the corneal scar. Larger grafts have |
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emergency basis. In case such a patient develops an |
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longer scars and are theoretically at higher risk of |
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infiltrate corneal scraping should be performed. The |
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dehiscence. Corneal wounds closer to the limbus heal |
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material obtained on corneal scraping should be |
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better. Post-penetratng keratoplasty corneal scars never |
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subjected to direct microscopy and cultures (bacteria |
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regain the normal corneal strength even after years. |
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and fungus). Intensive topical antibacterial/antifungal |
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Therefore corneal graft remains at risk of wound |
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treatment should be initiated in these patients. In case |
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dehiscence even after years. Bilateral wound dehiscence |
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of fungal keratitis systemic antifungal treatment should |
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has been reported. Bilateral poor visual acuity, alcohol |
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be given in moderate and severe keratomycosis. |
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abuse and use of non-inflammatory sutures are |
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predisposing factors. |
IRIS/CAPSULAR INCARCERATION |
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Immediate wound repair of the original graft is |
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needed. Even if the original graft is opaque or |
Any tissue iris or capsule tags incarceration in the corneal |
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edematous immediate primary repair is warranted. |
wound should be prevented. In case incarceration of |
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Delay in primary wound repair enhances the risk of |
the tissue is there it should be removed. In case it is |
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infective karatitis, suprachoroidal hemorrhage and |
persisting after primary repair, it should be treated |
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endophthalmitis. Advanced age is another risk factor |
during the second operation. Tissue incarceration may |
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for development of suprachoroidal hemorrhage. |
lead to wound leak, corneal fistula, inadvertent blebs, |
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endophthalmitis, fibrous ingrowth or epithelial |
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Prognosis |
downgrowth. The corneal fistula should be detected |
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Older patients record poor visual outcome after |
using Seidel’s test and should be treated immediately. |
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Fibrous ingrowth or epithelial down growth should be |
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treatment of traumatic wound dehiscence. |
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avoided as it may later lead to intractable glaucoma. |
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Traumatic iris cyst is a rare complication of full thickness |
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Complications of Corneal Injury |
corneal laceration (Fig. 9.7). |
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The objective of repair of anterior segment injury is to repair the damage, prevent the complications and provide effective visual rehabilitation to the patient. Following successful repair of the injury, the patient should be monitored for development of following complication. Traumatic cataracts were the most common vision-limiting factor in all categories of openglobe injuries. Injuries in zones II and III. Blunt-force
SECONDARY GLAUCOMA
Patients undergoing repair of eye injury should be closely mentioned for development of secondary glaucoma. Intraocular pressure should be recorded on every visit. In case of corneal scarring non-contact tonometer may be used to record IOP. In case IOP is high it should be controlled medically. Surgical option may be desirable once it is not controllable with medical
Management of Corneal Injuries |
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POST-TRAUMATIC ENDOPHTHALMITIS |
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Endophthalmitis following OGI is a serious complication. Microbial contamination is an important risk factor for development of endophthalmitis. Despite high frequency of microbial contamination, it develops only in few cases. Systemic antibiotics, virulence of organisms and host factors play role in the development of endophthalmitis. Poor vision at presentation, isolation of virulent organism, longer length of corneoscleral laceration (>8.0 mm), delayed primary repair (>72 hours) and uveal tissue and vitreous prolapse have been identified as risk factors favoring development of endophthalmitis.7 The incidence of endophthalmitis can be reduced by early referral of
Fig. 9.7: Iris cyst following repair of corneal laceration trauma cases.8 Prophylactic intravitreal broad spectrum antibiotic injection has been found to decrease the risk of post-traumatic endophthalmitis.9
In a recent series endophthalmitis due to Bacillus species has been reported. Bacillus isolates have been found to be sensitive vancomycin, gentamycin and fluoroquinolones.10 The organism was not found to be sensitive to penicllin or cefalosporins. Endophthalmitis caused by Bacillus cerus results in poor visual outcome.10
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SYMPATHETIC OPHTHALMIA |
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Sympathetic ophthalmia is defined as bilateral, granu- |
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lomatous, pan-uveitis generally occuring following |
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open globe injury or rarely following intraocular |
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surgery. Incidence between 0.2% and 1% has been |
Fig. 9.8A: Clear graft in a patient with corneal traumatic |
reported follwing open globe injury and 0.001% |
following surgery has been reported.11 Risk is more |
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corneal scar |
if the injury extends into the ciliary body region. Uveal |
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tissue/iris incarceration into the corneal or scleral wound |
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also enhances the risk of sympathetic ophthalmia. |
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Patient should be educated that difficulty in reading |
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may be the earliest sign of the disease. In the early |
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stage the disease present as granulomatous uveitis. |
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Once clinical diagnosis is established, the patient should |
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be put on topical and systemic steroids. |
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POSTERIOR SEGMENT COMPLICATIONS |
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Every patient suffering penetrating eye injury should |
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be subjected to the detailed retina evaluation even if |
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there is not obvious injury to the posterior segment. |
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These patients should be kept under follow-up. The |
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retina should be examined with scleral depression at |
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Fig. 9.8B: Ahmed gluaucoma valve for post-PK |
least 2 times a year. Patients who need penetrating |
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grafts or secondary scleral fixated PCIOL should be |
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glaucoma |
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critically examined for any retina problem before |
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treatment. Glaucoma may occur after penetrating |
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undertaking surgery. These patients may develop |
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keratoplasty done for visual rehabilitation. These cases |
retinal detachment months to years after the primary |
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may need glaucoma surgery, Ahmed valve to control |
repair. In case the media is not clear patient should |
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intraocular pressure (Figs 9.8A and B). |
undergo ultrasonography to rule out posterior segment |
48 |
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Clinical Diagnosis and Management of Ocular Trauma |
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problem before performing cataract surgery or |
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penetrating keratoplasty. |
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ASTIGMATISM |
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Patients with less than 3 mm corneal laceration usually |
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have corneal astigmatism (<3.00D) where as 4 mm |
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or longer incision has higher corneal astigmatism. Low |
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or moderate astigmatism (<3.00 D) is common and |
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can be easily managed with prescription of glasses. |
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High astigmatism (>3.00D) requires different set of |
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evaluation and management. High astigmatism may |
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occur despite meticulous primary repair.12 High |
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astigmatism with sutures still in place may decrease |
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with selective suture removal. Once all the corneal |
Fig. 9.9: Secondary scleral fixated intraocular lens |
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sutures are out, accurate refraction should be done. |
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In case of a child it should done as cycloplegic refraction. |
implant in patient with corneal injury |
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Best corrected visual acuity with spectacle correction |
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should be noted. In case visual acuity with pin hole |
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is better than spectacle correction, it means that there |
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is significant irregular astigmatism. Corneal topography |
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should be performed and surface regularity index may |
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be high in these cases. Such a patient should under |
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go rigid gas permeable contact lens trial. In addition |
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to irregular astigmatism, problems such as ametropia |
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following aphakia, high astigmatism or aniridia can be |
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solved with good visual results, good tolerance and |
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less complications.14 High astigmatism can be managed |
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with astigmatic keratotomy. LASIK, epi-LASIK and |
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photo-astigmaic keratotomy may be performed to treat |
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corneal ametropia and corneal astigmatism.12 |
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Visual Rehabilitation
In case visual acuity with spectacle correction does not improve RGP contact lenses should be considered. Reverse geometry RGP contact lens, with large diameters, could be another alternative in irregular corneal surface with corneal scar.13 Fluorescein pattern analysis could be better fitting technique in these cases. This fitting could involve less time and fewer visits. Computer-aided fitting was of limited value in these cases.14 In case patient does not want rigid gas permeable contact lens, the patient may be considered for alternate surgical options.
Patents intolerant to RGP may be considered for astigmatic keratotomy or laser vision correction. In case of child with poor compliance for contact lenses, secondary intraocular lens implantation may be useful in preventing amblyopia (Fig. 9.9).15
Patients who have corneal scar passing through the visual axis may need deep anterior lamellar keratoplasty or penetrating keratoplasty (Figs 9.10A and B). Secondary intraocular lens implantation if required may
Fig. 9.10A: Traumatic corneal scar involving visual axis
Fig. 9.10B: Clear graft in patient with traumatic corneal scar
be performed at the same sitting. In case the iris has been damaged iridoplasty may be performed. If the longer sector of the iris is missing the special intraocular lenses with opaque periphery may be implanted to avoid glass and improve cosmetic appearance.
Management of Corneal Injuries |
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WAR RELATED INJURIES |
it is possible to rehabilitate eyes with corneal injuries |
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The most common cause of the eye injuries during |
to near normal. |
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the war are explosions with fragmentation injury. Open |
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globe injuries, are more common and usually bilateral. |
References |
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OGIs received during war are for more serious and |
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devastating. It is difficult to salvage the eye. A large |
1. |
Pieramici DJ, Sternberg P Jr, Aaberg TM Sr, et al. A |
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number of eyes (30 to 35%) may need to be removed |
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system for classifying mechanical injuries of the eye |
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(enucleation, evisceration, or exenteration). Some of |
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(globe). The Ocular Trauma Classification Group. Am J |
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the patients may even require bilateral enucleation. |
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Ophthalmol 1997;123820-31. |
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Injuries to other body systems are common. In |
2. |
Chidiac EJ, Raiskin AO Succinylcholine and the open |
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Operation Iraqi Freedom 797 severe eye injuries |
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eye.Ophthalmol Clin North Am 2006;19:279-85. |
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including 483 OGIs (49 bilateral) were treated by |
3. |
Scott IU, Gayer S, Voo I, Flynn HW Jr, Diniz JR, |
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United States Army ophthalmologists.These injuries |
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Venkatraman A. Regional anesthesia with monitored |
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anesthesia care for surgical repair of selected open globe |
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were most commonly caused by explosion trauma.16 |
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injuries. Ophthalmic Surg Lasers Imaging 2005;36:122-28. |
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OGIs may also occur in survivors of terror attacks |
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4. |
Ram J, Sharma A. Traumatic implanation of cilia into the |
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victims that involve the use of explosive materials. |
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capsular bag. Afro Asian J Ophthalmol 1992;Vol |
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These explosives are commonly of a high explosive |
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XI(2):194-95. |
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type (HE) and may be fashioned into improvised |
5. |
Gupta A, Srinivasan R, Kaliaperumal S, Setia S. Microbial |
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explosive devices (IED) that incorporate additional |
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cultures in open globe injuries in southern India. Clin |
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materials to maximize trauma and injuries. Serial IED |
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Experiment Ophthalmol. 2007;35:432-38. |
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explosions have occurred in commuter trains in several |
6. |
Hamill MB. Corneal and Scleral trauma. Ophthamol Clin |
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cities including London, Madrid and Mumbai. In a |
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N Am 2002;15:185-94. |
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7. |
Gupta A, Srinivasan R, Gulnar D, Sankar K, Mahalakshmi |
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report 16 of 28 patients (57.1%) had ocular injuries |
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T. Risk factors for post-traumatic endophthalmitis in |
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whereas 12 (42.8%) were found to be normal. Injuries |
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patients with positive intraocular cultures Eur J |
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were seen in 22 eyes, 10 unilateral and six bilateral. |
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Ophthalmol 2007;17(4):642-47. |
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The common injuries were periorbital hemorrhages |
8. |
Narang S, Gupta V, Simalandhi P, Gupta A, Raj S, Dogra |
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(09 eyes, 40%); first or second degree burns to the |
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MR. Paediatric open globe injuries. Visual outcome and |
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upper or lower lids (seen in 07 eyes, 31.8 %) and |
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risk factors for endophthalmitis. Indian J Ophthalmol |
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corneal injuries (seen in 08 eyes, 36.3%). Open globe |
9. |
2004;52:29-34. |
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injuries were seen in two eyes of two patients (09%). |
Narang S, Gupta V, Gupta A, Dogra MR, Pandav SS, Das |
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S. Role of prophylactic intravitreal antibiotics in open |
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One patient (4.5%) had a traumatic optic neuropathy.17 |
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globe injuries. Indian J Ophthalmol 2003;51:39-44. |
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Ophthalmologists should be aware of this pattern |
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10. |
Miller JJ, Scott IU, FlynnHW Jr, et al. Endophthalmitis |
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of ocular injuries. Protocols should include the |
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caused by Bacillus species. Am J Ophthalmol |
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screening of patients in a short time, diagnostic tests |
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2008;145:883-88. |
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including B-scan, visual evoked potential (VEP), etc |
11. |
Marak GE. Recent advances in sympathetic ophthalmia. |
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and performing early surgery at the time of injury. |
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Surv Ophthalmol 1979;24:141-56. |
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Most of the severe eye injuries are missed and are not |
12. |
Jain S, Azar DT, Pineda RP. Management of astigmatism |
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treated at an initial assessment. |
13. |
after corneal trauma. Int Ophthalmol Clin 1986;47-55. |
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Martin R, de Juan V. Reverse geometry contact lens fitting |
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Prevention of Eye Injuries |
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in corneal scar caused by perforating corneal injuries. |
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Cont Lens Anterior Eye 2007;30:67-70. |
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14. |
Grünauer-Kloevekorn C, Habermann A, Wilhelm F, |
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Occupational open globe injuries are usually severe |
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Duncker GI, Hammer T. Contact lens fitting as a possibility |
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and are associated with a poor visual outcome. |
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for visual rehabilitation in patients after open globe |
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Mandatory use of protective eyewear and alcohol-free |
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injuries Klin Monatsbl Augenheilkd 2004;221:652-7. |
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environment at the work place is likely to reduce the |
15. |
Sharma A, Basti S, Gupta S. Secondary IOL implantation |
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incidence of severe occupational open globe injuries. |
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in children. J Cataract Refract Surg 1997;23:675-680. |
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Educating parents and children about the potential |
16. |
Thach AB, Johnson AJ, Carroll RB, Severe eye injuries |
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for eye injuries at home and during hazardous activities |
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in the war in Iraq, 2003-2005 |
Ophthalmology |
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2008;115:377-82. |
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should be an important public health goal.18 In |
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17. |
Mehta S, Agarwal V, Jiandani P. Ocular injuries in |
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addition, promoting the use of appropriate protective |
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survivors of improvised explosive devices (IED) in |
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eyewear by children during activities with a high risk |
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commuter Trains BMC-Emerg Med 2007;27;7:16. |
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of ocular trauma will help prevent future eye injuries. |
18. |
Brophy M, Sinclair SA, Hostetler SG, Xiang H. Pediatric |
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Although the path is long and arduous but with |
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eye injury-related hospitalizations in the United States. |
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the current advancements in microsurgical techniques |
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Pediatrics 2006;117:1263-71. |
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C H A P T E R
10Chemical Injuries of the Eye
Quresh B Maskati (India)
Introduction
Among the ocular hazards that modern day humans face, the incidence of chemical injuries has been forever on the rise. Causes range from industrial and agricultural accidents, domestic accidents, assaults and chemical warfare. Uncommon causes are self inflicted injuries and improper use of drugs.1,2
The eye is exposed to a wide variety of chemicals of diverse nature, either by accident or design. The injuries so caused vary considerably, from the most trivial causing transient irritation to the most severe, causingcompletelossofintegrityofthevisualapparatus.
The protective mechanisms of the eye are generally of not much help in these types of injuries. The bony orbit protects against large size objects, but offers no barrier to liquids and gases. The eyelids may suffer extensive damage themselves in cases of chemical injury. Liquids mix with tears and spread rapidly, extending the area of contact. Reflex lid closure and blepharospasm may trap solid particles, especially lime, beneath the lids, leading to prolonged contact.1,2
Pathogenesis
The commonest types of chemicals are acids and alkalis. Most chemical injuries have a striking similarity in their pathogenesis, following the pattern of acid or alkali burns.
severe disruption of stromal mucopolysaccharides. Thus they are able to progressively penetrate deeper into the stroma. Alkali injuries are hence considered to have a poorer prognosis as compared to acid injuries.3
Classification
Several classifications have been in vogue in the past.
a.Hughes’ classification: Mild, moderate and severe. This depended on the visibility of anterior chamber details and the blanching of the surrounding conjunctiva. However, it did not assess the area of surface involvement.
b.Thoft’s classification: 4 grades of severity from grade1 to grade 4 based on area of perilimbal conjunctival necrosis and amount of corneal epithelial loss.4
However, in those days, the concept of limbal stem cells and their role in regeneration of the conjunctival and corneal epithelium was not well understood. Modern classifications such as that proposed by Dr. Harminder Dua of Nottingham, UK (Table 10.1) fill in that lacuna and hence give the reviewer a better idea of the prognosis of such cases.7
Management
GENERAL PRINCIPLES
ACIDS
They cause their damage within the first few hours. They produce a coagulation of the surface proteins into insoluble acid albuminates, which form a barrier to further penetration. Therefore the damage is restricted and the lesions are sharply demarcated and nonprogressive.
ALKALIS
These cause a saponification of cellular barriers, denaturation of mucoids, swelling of collagen and
First Aid
This consists of immediate and thorough removal of the chemical to the extent possible. Ideally the antidote of the chemical can be used. Practically this is usually not feasible—the easiest way is a liberal washing of the eye with Ringers lactate or Normal saline or even tap water, if nothing else is available, for 30 to 60 minutes.
Examination
A thorough examination of the involved structures is then carried out with a good illumination (slit lamp,
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Chemical Injuries of the Eye |
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51 |
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TABLE 10.1: Dua classification of chemical burns |
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Grade |
Prognosis |
Clinical findings |
Conj.involvement |
Analogue scale |
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I |
Very good |
0 clock hours of limbal involvement |
0% |
0/0% |
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II |
Good |
< 3 clock hours of limbal involvement |
<30% |
0.1-3/1-29.9% |
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III |
Good |
>3-6 hours of limbal involvement |
>30-50% |
3.1-6/31-50% |
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IV |
Good to guarded |
>6-9 hours of limbal involvement |
>50-75% |
6.1-9/51-75% |
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V |
Guarded to poor |
>9-<12 hours of limbal involvement |
>75-<100% |
9.1-11.9/75.1-99.9% |
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VI |
Very Poor |
Total limbus (12 hours) Involved |
Total conj (100%) |
12/100% |
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The analogue scale records accurately the limbal involvement in clock hours of affected limbus/percentage of conj. |
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Involvement. While calculating percentage of conj. Involvement, only involvement of bulbar conjunctiva, up to and including |
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the conjunctival fornices is considered. |
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if possible) and the extent of damage assessed. Any particles, especially in cases of lime are picked up with a forceps or a cotton bud. The fornices must be searched well, with double eversion of the lids, which will reveal trapped lime particles. If the patient is a child this may require examination under general anesthesia as soon as the general condition of the patient permits. The author has discovered lime particles deep in the fornix even months after the injury, which have been missed by others because the child was not examined under general anesthesia with double eversion. Special attention is paid to examination of the adnexa, as their involvement will considerably worsen prognosis. Also, the lesions are graded according to Dua’s or any other classification.
Medication
Topical anesthetics should be sparingly used, as they tend to retard epithelial healing. Systemic analgesics can be administered. A cycloplegic like atropine should be instilled to reduce the pain and discomfort of Cyclitis. Topical antibiotics should be used to prevent infection. Acetazolamide should be started in cases with moderate to severe burns to prevent secondary glaucoma. This is a wise precaution, as intraocular pressure cannot be taken in the early stages of chemical injuries.
Surgical Maneuvers
Early paracentesis has been recommended, especially in cases of alkali burns, though its advantages have not been proved. Mechanical removal of contaminated, necrotic tissue will promote faster healing. According to a study done at L.V. Prasad Eye Institute, use of amniotic membrane grafts in the early stages significantly reduced overall morbidity of chemical burns lesions.6 Sweeping of a glass rod around the fornices is done daily, especially in the areas where symblepharon is threatening to develop. A conformer or moulded scleral contact lens can also be inserted to prevent symblepharon.
Role of Vitamin C
Topical ascorbic acid has been advocated to promote corneal regeneration as it has been found that the aqueous in most cases of chemical injuries, especially alkali are markedly scorbutic (very low to unrecordable levels of vitamin C). Ascorbic acid is very necessary for fibroblasts to lay down healthy collagen.4 This reparative process starts soon after the injury occurs. This is a cheap and freely available drug. It is sold as ampoules of 500 mg in 5 cc or as 1000 mg in 10 cc. This is the exact concentration that is required of topical vitamin C, i.e. 10%. It does not need any further dilution. All you have to do is break an ampoule of vitamin C injection, pour into a sterile glass bottle, put an eyedropper on the mouth of the bottle and dispense. In case ampoules of vitamin C are not available, tablets of Vitamin C, 500 mg can be dissolved in distilled water (5 cc) and dispensed. The drops should be used frequently – every few minutes for the first 2 hours and then hourly for the first 48 hours. They can be continued 4-6 times a day for the first couple of weeks. Studies have shown this significantly reduces the risks of perforations and cornel melts.
Autohemotherapy
Many researchers have tried the use of blood and blood products in the treatment of chemical injuries and some of the earliest results of this technique were reported by Dubrovina (1951). In fact it is even mentioned in the early Duke-Elder (2) volumes on ophthalmology, now sadly no longer looked at by most postgraduates! In this technique, 0.5 to 1.5 ml of the patient’s own venous blood drawn from the ante-cubital vein is injected under the conjunctiva in the perilimbal region and in the fornices. This is repeated every other day or as required. The aim of this therapy is manifold. Blood acts as a buffer, ensures more intimate contact with the diffusing chemical, than that achieved by surface irrigation. It thus causes a dilution of the chemical, besides ensuring separation of the tissues
52 |
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Clinical Diagnosis and Management of Ocular Trauma |
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and acting as a barrier against deeper penetration. This |
burns, there are several options. If there is an |
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is of great advantage, especially in severe alkali burns. |
unaffected area, a small piece of limbal tissue can be |
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Also, its fibrinolytic action tends to inhibit the formation |
cultured in vitro and the cultured stem cells can be |
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of symblepharon and it acts as a cushion in between |
transplanted to one or both eyes. The other option |
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the superficial and deeper tissues. Platelets fill the gaps |
is use of stem cells donated by living related donors. |
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on the denuded surface. They also adhere to collagen |
If these are not possible, one can use cadaveric stem |
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by changing their shape from the usual oval to an |
cells from eye bank eyes. In all these cases however, |
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amoeboid shape. Antiproteases in the blood inhibit |
it is mandatory to give prolonged systemic |
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collagenases, preventing the breakdown of newly |
immunosuppressive therapy for a period of at least |
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formed collagen. |
6 months. Several authors are in favor of much longer |
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dosage regimens, over years. Stem cell transplant is |
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Newer Drugs |
usually always done in association with amniotic |
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There is increasing research on the use of citrates, |
membrane transplantation. |
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progesterone, epidermal growth factors and some |
Amniotic Membrane Transplant |
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other medications to promote healing. It may be a |
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few years before they attain mainstream status for use |
As said earlier, in partial stem cell deficiency, it may |
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in all cases. |
be sufficient to repeatedly scrape the diseased |
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epithelium and place a large piece of amniotic |
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RECENT ADVANCES IN THERAPY |
membrane tissue (AMT) over the cornea. Amniotic |
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Stem Cells |
membrane is the innermost lining of the foetus and |
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is obtained from healthy donors who are HIV free, |
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It is now well established that stem cells for the cornea |
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delivered by cesarean section. Ideally, the membrane |
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as well as conjunctival epithelium are located in the |
is preserved in liquid nitrogen after mounting on |
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limbal palisades of Vogt. In chemical injuries one or |
specially treated nitrocellulose paper for 6 months. The |
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more clock hours of the limbus may be affected, |
mother is then retested for HIV to eliminate the window |
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causing destruction of these cells. These stem cells, in |
period effect. If negative, the AMT can be used in the |
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normal circumstances, divide into daughter cells, which |
manner described above. AMT has several properties, |
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undergo transformation into ‘transient amplifying cells’ |
which make it an ideal tissue – it down regulates |
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then into ‘terminally differentiated cells’ as they move |
inflammatory processes and up regulates healing |
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into the cornea, finally forming healthy corneal |
processes. It also provides an ideal substrate for |
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epithelial cells. If the stem cells are destroyed, healthy |
epithelial cells to grow over it and populate the areas |
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corneal epithelium will not fill the surface defects. This |
of epithelial defects. AMT has 2 sides – a smooth side, |
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causes persistent epithelial defects. These invite |
which is the epithelial side and a sticky side, which is |
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vascularization and ‘conjunctivalization’ or growth of |
the stromal side. It has increasingly wider applications |
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cells of conjunctival phenotype on the corneal surface. |
in anterior segment surgeries, such as in pterygium |
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Penetrating keratoplasties in cases with stem cell |
repair, which are outside the scope of this chapter. It |
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deficiency are doomed to failure for cast off corneal |
is occasionally used in acute chemical burns |
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epithelium cannot be replaced from the depleted stem |
management for its antiinflammatory properties. The |
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cell reservoir. Diagnosis of stem cell deficiency can be |
greater the inflammation, the faster the AMT gets |
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made by direct observation of loss of the limbal |
absorbed, but not before down regulating the existing |
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palisades and limbal ischemia and by indirect evidence |
inflammation. However, it is more commonly used in |
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such as persistent epithelial defects, conjunctivalization |
‘cold’ cases, in partial stem cell deficiency and in total |
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and vascularization of the cornea in cases of chemical |
stem cell loss (in combination with stem cell transplants). |
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burns. |
It handles fairly easily and can be sutured using either |
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If there is a partial stem cell deficiency, it can be |
8/0 polyglycolic acid sutures or 10/0 nylon. It can be |
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treated by scraping of the conjunctivalised area of the |
sutured directly on the cornea. It can also be used |
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cornea and amniotic membrane grafting. This gives |
for symblephara release and fornix reconstruction. |
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a chance for the distal, unaffected stem cells to grow |
Here, after release of the symblephara, the AMT is |
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down and populate the areas of stem cell loss. This |
pushed deep into the fornices. Sutures passed through |
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process may have to be repeated several times.7 |
the AMT are brought out through the eyelid and |
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If however, there is a total or near total stem cell |
sutured over small cut pieces of rubber tubing on the |
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deficiency, the stem cells need to be transplanted to |
outside. Results are amazing – patients with moving |
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the affected eye. The donor stem cells can be taken |
body vision can regain 6/6 vision with a combination |
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from the other eye in unilateral burns (ideal). In bilateral |
of stem cells and AMT! |
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Chemical Injuries of the Eye |
53 |
Keratoprosthesis
In cases where there is total stem cell loss and bilateral blindness with disfigured anterior segments and gross tear deficiency, the above 2 treatments will not help. These are the cases where Keratoprosthesis surgery (KP) has a role. This surgery is reserved for those who have good perception of light with accurate projection in the better eye and a B-scan showing attached retina. There are several types of KPs available in the world. The commonly used ones are the Dohlmann’s, the Pintucci and the OOKP (osteo-odonto-KP). The largest number of KPs implanted is the Singh-Worst KPs. The author has till date (2008) done 75 Pintucci KPs with a 11-year follow-up. 65% of operated patients regained useful vision i.e. they were able to carry out activities of daily living independently. This is the largest series of KPs in Asia outside Amritsar.
Fig. 10.3: Post-alkali burns pseduopterygium
Fig. 10.1: Acid burns with pseudopterygium
Fig. 10.4: Chemical burn treated with subconjunctival venous blood
Conclusion
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Chemical injuries are increasing in the modern world. |
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Acids and alkalis are the main chemicals implicated. |
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Emergency treatment if reported early may make all |
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the difference between saving the eye and irreversible |
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blindness. Early use of cheaply and freely available |
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treatments such as topical vitamin C and auto- |
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hemotherapy can reduce morbidity in these cases |
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Modern methods of managing post-burns corneal |
Fig. 10.2: Acid burns |
problems such as AMT, stem cell transplant and finally |
54 |
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Clinical Diagnosis and Management of Ocular Trauma |
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Keratoprosthesis have considerably improved overall |
4. Sfalangakos L, Tranos, Mitsonis J, Kouroubetsis J. The |
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prognosis in these unfortunate patients. |
management of chemical burns of the cornea. The cornea |
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in health and disease. Abstracts of VI Congress of |
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References |
European Society of Ophthalmology 1980;245. |
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5. Thoft RA, Friend J Kenyon KR. Ocular Surface response |
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to trauma. International Ophthalmology Clinics. Summer |
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1. Duke Elder, Sir Stewart. Diseases of the Outer Eye. Henry |
1979;19(2). |
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6. Sridhar MS, Sridhar MS, Bansal AK, Sangwan VS, Rao |
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Kimpton Publishers 1965;8(2):604-31,995-1002. |
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GN. Amniotic Membrane Transplantation in Acute |
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2. Duke Elder, Sir Stewart. Non-Mechanical Injuries. Henry |
Chemical and Thermal Injury. American Journal of |
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Kimpton Publishers; 1972;Vol. XIV, Part 2:011-1088. |
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Ophthalmology July 2000;130:134-36. |
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3. Henriquez AS. Scanning Electron Microscope in |
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7. Dua HS, King AJ, Joseph A. A New classification of |
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Experimental Alkali Burnt Corneas. Abstracts of VI Congress |
Ocular Surface Burns. Br J Ophthalmol 2001;85: |
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of European society of Ophthalmology 1980;240. |
1379-83. |
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C H A P T E R
11Injuries of the Eye due to
Physical Agents
(Thermal, Ultrasonic and Electrical Injuries)
Rupesh V Agrawal (India)
Introduction
The injuries to the eye due to physical agents can result from thermal, ultrasonic or electrical agents in addition to radiation injuries of the eye. In the present chapter, we will highlight:
I.Thermal injuries to the eye. II. Ultrasonic injuries to the eye. III. Electrical injuries to the eye.
Non-mechanical Eye Injuries
•Radiational injuries
•Thermal injuries
•Ultrasonioc injuries
•Electrical injuries
Thermal Injuries
The injuries of the eye and the adnexa can be caused by both extremes of temperature and are hence associated with thermal burns and freezing or exposure to cold.
HYPERTHERMAL INJURIES
Flame Burns
It can occur secondary to explosion of stove/Gas heater, industrial cases – from high temperatures and inflammable fluids, gases, Ovens, Furnaces, petrol stores, burning building wherein people are trapped, accidents in travel, in automobiles, trains, ships, airplanes, in war-the flame thrower, the napalm bomb, explosive fire in the confiance of tank on land, burning plane in the air, explosion of gun-turret of a ship, tragedy of swimming through boiling or burning oil floating on the sea.
however the tarsal plates remain intact, cornea shrivelled, ocular tissues damaged in varying degrees, in worst cases whole eye and the orbital contents incinerated, areas of black eschar may appear which as they fall off leave raw islands, extensive loss of tissue on forehead, cheeks, eyelids leads to black and shapeless mask, infection can occur and can spread inwards causing orbital cellulitis and infective dacryoadenitis. Healing is slow and can leads to inexorable contraction distorting the face.
Contact Burns
It can occur secondary to contact of the eye and the adnexa with lighted ends of cigars or cigarettes, shreds of tobacco from pipes, head of lighted match or a firework, glowing coal or hot cinders from a fire, industry-flying pieces of glowing metal, slag, solder, lead or glass or with solid bodies such as slag, molten metal with high melting point such as iron, molten glass, very hot bodies above 1000°C.
Clinical lesions: In the conjuntiva, hyperemia, violent chemosis, greyish white coagulated plaque. In the cornea – superficial or deeper burns, superficial burnswillbegreyoryellowishcloudingoftheepithelium which develops into erosion whereas in deeper burns cornea become grey and opaque like ground glass or white like procelain, a line of demarcation eventually forms and the slough is cast off, leaving an ulcer which if deep becomes infected and may perforate. Healing is by formation of fibrous tissue, resultant leucoma is permanent.The other complications of contact burns can be bullous keratitis, ectasia, corneal staphyloma, pseudopterygium, symblepharon and on the other handdeeplypenetratinglesioninvolvesthesclerawhich may be perforated resulting in prolapse of uvea and vitreous, purulent uveitis, panophthalmitis.
Clinical lesions: Eyes themselves are rarely involved in a flame burn unless the heat is intense and prolonged, lashes and brows may be scorched, skin of the lids deeply burned, lids may be destroyed,
Scalds
It occurs secondary to burns by hot fluids affecting the lids, can lead to conjunctival swelling and chemosis and symblepharon in chronic cases.