Ординатура / Офтальмология / Учебные материалы / Clinical Diagnosis and Management of ocular trauma

Management of a Malpositioned

IOL

Disturbing visual symptoms such as diplopia, metamorphopsia, and hazy images are associated with a dislocated intraocular lens (IOL) (Fig. 52.1). If not properly managed, a malpositioned IOL may also induce sight-threatening ocular complications, including persistent cystoid macular edema, intraocular hemorrhage, retinal breaks, and retinal detachment. Contemporaneous with advances in phakonit microsurgical techniques for treating cataracts, a number of highly effective surgical methods have been developed for managing a dislocated IOL.

Chandelier Illumination

Visualization is done using a Chandelier illumination in which xenon light is attached to the infusion cannula. This gives excellent illumination and one can perform

Fig. 52.2: IOL lying over the macula. Notice the wide field view of the retina. This is because of the wide field contact lens being used and the Chandelier illumination which is seen in the upper left hand corner

Fig. 52.3: View using the super macula lens. This gives better steropsis

Fig. 52.4: Diamond tipped forceps lifting a looped IOL lying on the retina after a vitrectomy

Fig. 52.5: Forceps holding the IOL and the vitrectomy probe cutting the vitreous adhesions. This is bimanual vitrectomy which is possible due to the Chandelier illumination

Fig. 52.6: Handshake technique. Using two forceps one can hold the IOL comfortably and bring it anteriorly

Fig. 52.7: IOL brought out anteriorly through the limbal route. Notice in the upper right and left corners infusion cannulas fixed. One is for infusion and the other for the Chandelier illumination. One can also have the same infusion cannula with the Chandelier illumination

holding the IOL with a diamond tipped forceps (Fig. 52.4). When one is using the Chandelier illumination system one hand can hold the IOL with the forceps and the other hand can hold a vitrectomy probe to cut the adhesions of the vitreous thus doing a bimanual vitrectomy (Fig. 52.5). One can also use two forceps to hold the lens thus performing a hand shake technique (Fig. 52.6). The lens is then brought out anteriorly and removed through the limbal route

(Fig. 52.7).

Reinverter System

When we use the wide field indirect contact vitrectomy lenses we have to use a reinverter as the image is seen inverted. The reinverter again makes the image erect so that the surgeon does not have difficulty in operating. The one we use is the one from Zeiss microscopes which has a foot switch connection. In

Wide Field Indirect Contact

Vitrectomy Lenses

These are essential for performing proper bimanual vitrectomy. When one is doing vitrectomy for dropped IOL we use the Mini Quad Volk lens or the Oculus lens. These lenses give the view of the retian upto the ora serrata. When one wants to pick up the IOL with the diamond tipped forceps then we use the Supermacula Volk lens. This lens gives very high magnification. Another advantage of this lens is the better steropsis so that you know exactly where the IOL haptic is in relation to the retina. These lenses come with a handle so that the assistant can hold the lens comfortably.

Bimanual Vitrectomy

The advantage of the bimanual vitrectomy set-up is that the hand which normally holds the endoilluminator

References

1.Agarwal A, Agarwal S, Agarwal A. Phakonit: Lens removal through a 0.9 mm incision. In: Agarwal A Phacoemulsification, Laser Cataract Surgery and Foldable IOL’s First edition. Jaypee Brothers 1998.

2.Agarwal A, Agarwal A, Agarwal S. No Anesthesia Cataract surgery. In: Agarwal A Phacoemulsification, Laser Cataract Surgery and Foldable IOL’s Second edition. Jaypee Brothers 2000.

3.Chang S. Perfluorocarbon liquids in Vitreo-retinal surgery. International Ophthalmology Clinics-New approaches to vitreo-retinal surgery: Vol32, No.2, Spring 92: 153-63.

4.Chan CK, An improved technique for management of dislocated posterior chamber implants. Ophthalmol 1992; 99:51-57.

5.Chan CK, Agarwal A, Agarwal S, Agarwal A. Management of dislocated intraocular implants. In: Ophthalmology Clinics of North America, Posterior Segment Complications of Cataract Surgery, December 2001; editors: P.N. Nagpal, I. H. Fine; W. B. Saunders, Philadelphia 681-93.

Introduction

Ocular trauma classification groups has classified mechanical injuries to the eye into 2 categories.

1.Open globe: Full thickness defect in corneoscleral coat of the eye and

2.Closed globe : Ocular injuries without full thickness defect of the globe

Classification

Mechanical Eye injury can be classified as follows

(Table 53.1).

DIFFERENT TERMS USED IN OCULAR TRAUMA

•Closed globe: Eye wall does not have a full thickness wound.

•Open globe: Eye wall has a full thickness wound.

•Laceration: Full thickness wound caused by a sharp object.

•Penetrating injury: Single full thickness wound caused by a sharp object.

•Intraocular foreign body (IOFB): Retained foreign body causes a single entrance wound.

•Perforating injury: Two full thickness woundsentry and exit wound.

•Contusion: Closed globe injury resulting from a blunt object.

PROGNOSTIC FACTORS

Despite of advances in ocular imaging, instrumentation, materials, and surgical procedures, the management of open globe injuries continue to pose difficult management dilemmas. Prognosis depends on various factors such as initial visual acuity, presence or absence of relative afferent pupillary defect, type and zone of injury, time elapsed between the injury and surgery, cataract formation or dislocation of lens and also presence or absence of retinal detachment or endophthalmitis.

Closed Globe Injuries

ANTERIOR SEGMENT TRAUMA CORNEAL INJURIES

This is one of the most common ophthalmic emergencies.

The most common presentations are:

1.Corneal Foreign Bodies

2.Lamellar Corneal Lacerations

3.Vossius Ring

4.Traumatic Hyphema

5.Traumatic Cataract

Corneal Foreign Bodies

Clinical features

•Foreign Body Sensation

•Conjunctival Congestion

•Watering of Eyes

•Photophobia

Ocular examination may reveal edematous lids. Slit

Lamp examination shows foreign body embedded in the corneal epithelium.

Management: After informing the patient about the procedure, instill topical anaesthetic drops into the eye. Also explain to the patient about infection and sensation of foreign body in the affected eye.

Lamellar Corneal Lacerations

History: The patient usually presents with history of injury or unconsciousness, convulsions, bleeding from nose, ears, etc.

Evaluation: The patient is subjected to a complete general and ophthalmic examination, including Slit Lamp Examination, which is a must. Determination of visual, acuity and Siedel’s Test should be performed in all cases of occult injury.

Siedel's Test: This test is performed to rule out occult perforation of Descemet's Membrane. In positive cases, there is a high risk of endophthalmitis and hypotony.

Traumatic hyphema

Traumatic hyphema generally occurs in young active people, predominantly males, and also children, accounting for nearly 50% of all eye injuries.

The mechanism could either be due to direct impact, compressive wave force, reflected compressive wave or rebound compressive wave. It is usually caused by a high velocity projectile or an object which strikes the exposed portion of the eyeball, the total extent of the damage depending upon the nature, size, anatomical location and force of impact.

The most common causative factors are balls, rocks, toys, human fists and gun pellets, etc. The usual effect of a blunt compressive force onto an eyeball results in the sudden decrease in the antero posterior dimensions of the eyeball, thus causing a compensatory increase in the anterior equatorial circumference of the globe. This leads to the posterior displacement of the iris-lens diaphragm, with scleral expansion in the equatorial zone. This, in turn leads to shearing and disruption of the circulus arteriosus iridis major, arterial branches of the ciliary body, and / or recurrent choroidal arteries and veins, crossing between the ciliary body and episcleral venous plexus, resulting in hyphema. In cases where no layering of blood is visible in the anterior chamber, but few red blood corpuscles are

COMMOTIO RETINAE (BERLIN'S EDEMA)

Commotio Retinae was first described by Berlin in 1873. It is seen as a greyish white Opacification of the outer retina. It always typically occurs opposite to the site of impact and may occur anywhere in the posterior segment. Visual acuity is usually affected if macular edema is involved. Histological examination shows that there is edema in the outer retinal layers along with some photoreceptor loss. Fluorescein Angiography shows no breakdown in the Blood Retinal Barrier. Later in the course, RPE mottling shows areas of hyper and hypofluorescence. The prognosis is usually good with the lesions resolving completely or with varying degrees of RPE mottling.

CHOROIDAL RUPTURE (FIG. 53.1)

Indirect choroidal ruptures result from compressive injury to the posterior pole of the eye.11 With the horizontal expansion of the globe, the elastic retina and tough sclera resist tearing, but the Bruch's membrane is prone to rupture. Classically, the ruptures at the site of trauma may also be seen, which tend to be anterior and parallel to the ora. Choroidal ruptures are typically singular, concentric to the disc and temporal. Initially they may be obscured by overlying hemorrhage and become visible later. The visual acuity is affected if it passes through the fovea. FFA may be of use to detect small ruptures and the location in relation to the foveal centre. The ruptures

Fig. 53.1: Choroidal rupture

TRAUMATIC MACULAR HOLE (FIG. 53.2)

Trauma accounts for 9% of Full Thickness Macular Holes. They may occur due to posterior contusion necrosis, following subfoveal hemorrhage or due to acute vitreo retinal traction. The size varies from 300μ - 500μ with a sharp irregular margin and a cuff of neuro sensory detachment. It rarely leads to a retinal detachment. OCT is the best method to demonstrate a macular hole. Surgical anatomic closure is achieved in 93% cases following vitrectomy with membrane peeling and fluid gas exchange. They show good visual recovery perhaps due to the younger age of the patients and early diagnosis.

Fig. 53.2: Traumatic macular hole

PUTSCHER'S RETINOPATHY

Severe headtrauma or chestcompression inthe absence of direct trauma to the globe results in Putscher's Retinopathy. Its frequency is unknown. It is characterised by multiple patches of superficial retinal whitening and retinal hemorrhage surrounding a hyperaemic Optic Nerve Head. It is seen in subjects with head injury, chest compression injury, acute pancreatitis, childbirth, connective tissue disorders and retrobulbar anaesthesia. Though the pathogenesis is not well understood, the entire picture above has in common, the ability to activate massive amounts of complement. The resultant leukoemboli may be a source of retinal arteriolar embolization.AsimilarpictureisseenintheFatEmbolism Syndrome in patients with fractured medullated bones.

Fig. 53.4: Optic nerve avulsion

TRAUMATIC OPTIC NEUROPATHY

Damage to one or both nerves may occur with blunt trauma to the head. Prognosis for recovery of vision is poor. Treatment with high dose corticosteroids has been advocated along with surgical decompression in selected cases.

Corneoscleral Laceration with Lens and Vitreous Involvement

Large corneal lacerations or small penetrating injuries caused by projectiles can cause significant lens damage. The decision about lens removal depends on critical pre and intra-operative assessment. If lens capsule is ruptured and surgical visualization is adequate, it is preferable to complete all operative interventions at one session. In cases with posterior capsular rupture with vitreous involvement, lensectomy with pars plana vitrectomy are advisable. Primary IOL insertion should not be performed if there is vitreous in AC or surgical visualization is poor. Wound should be watertight and free of vitreous incarceration at the conclusion of surgery.

Corneoscleral Laceration with Tissue Loss

Small punctured wounds may simply be sutured tightly. For large tissue loss, tissue replacement techniques such as full thickness and lamellar patch graft are more appropriate for restoration of structural integrity without astigmatism inducing distortion. Primary penetrating keratoplasty with anterior segment reconstruction are the definitive treatment for complex injuries with extensive tissue loss.

Irreparable Scleral Rupture

Badly ruptured eyes with extensive tissue loss and no visual function should be enucleated in the interest of the other eye.

Postoperative Management

Appropriate medical therapy comprising of systemic and topical antimicrobials to control infection and corticosteroids to minimize inflammation and scarring, should be instituted. Anti-glaucoma therapy for IOP control and lubricants or bandage contact lens for ocular surface stabilization may be required.

Posterior Scleral Laceration

Scleral lacerations without corneal involvement may be difficult to diagnose due to relatively formed eyeball and anterior chamber. Signs of posterior rupture include bullous sub-conjunctival hemorrhage, poor vision, shallow or very deep anterior chamber, low IOP, rarely high IOP due to choroidal hemorrhage, hyphema and distorted pupil. Their management requires a 360°. Conjunctival peritomy, followed by

Conclusion

The management of open globe injuries continues to pose difficult management dilemmas. The standard practice worldwide in these cases should be to undertake a primary surgical repair to restore the structural integrity of the globe at the earliest opportunity regardless of the extent of the injury and the presenting visual acuity. Despite microsurgical improvements in management in this devastating