Ординатура / Офтальмология / Английские материалы / Pediatric Opthalmology_Mukherjee_2005

E.The diagnosis is confirmed by measuring intraocular tension, corneal diameter, gonioscopy and evaluation of optic nerve head.

Differential diagnosis of primary buphthalmos consists of all cases with

A.Watering of the eye.

B.Photophobia and blepharospasm

C.Cloudy cornea

D.Prominent eyeball in a neonate.

A.Watering should not be mistaken as congenital nasolacrimal duct obstruction, ophthalmia neonatorum or corneal abrasion.

1.The congenital nasolacrimal duct obstruction generally manifests after three weeks of birth, has mucoid or mucopurulent discharge may have positive regurgitation test. The cornea is bright, anterior chamber depth is normal and pupil of normal size and reaction.

2.Ophthalmia neonatorum develops within first three to four days. It is invariably bilateral, the lids are moderately edematous, discharge is purulent. Regurgitation test is negative, cornea AC and pupil are within normal range.

3.Corneal abrasion are mostly due to birth trauma. The discharge is watery. The abrasion stains with fluorescein, otherwise cornea, AC and pupil are normal.

B.Photophobia and blepharospasm are generally due to corneal abrasion, neonatal keratitis and anterior uveitis. Interstitial keratitis comes into differential diagnosis only if a child with lacrimation and photophobia present after three years of age. The cornea in interstitial keratitis has uniform haze due to deep vascularisation.

C.Cloudy cornea :

Cloudy cornea may be due to

1.Endothelial dystrophy

2.Mucopoly saccharoidosis

3.Mucolipidosis

D.Prominent eyeball. causes of prominent eyeball in neonate may be :

1.True proptosis due to a retro bulbar mass and craniocynostosis and congenital myopia.

E.Other causes of secondary and associated glaucoma in children should be excluded.

Clinically and by specialised investigation like :

1.Ultrasonography

2.X-ray skull and orbit

3.CT

4.M.R.I.

The conditions that require special attention are retinoblastoma, retinopathy of prematurity, persistent primary hyper plastic vitreous41,42.

Management of primary buphthalmos. The definitive treatment of primary congenital glaucoma is surgery. Medical treatment is employed for temporary reduction of

intraocular pressure till the facility of surgery becomes available, sometime medical treatment may have to be re-introduced after surgery to control residual glaucoma.

Treatment of primary buphthalmos is divided into :

A.Specific

1.Surgery

2.Laser

3.Medical

B.Ancillary treatment consists of management of

1.Associated errors of refraction.

2.Prevention and management of amblyopia.

3.Low vision aid.

4.Rehabilitation.

1. Surgery consists of various microsurgical procedures.34, 35, 37, 40, 41, 42 They are : (a) (i) Goniotomy through operation gonioscope.

(ii) Direct goniotomy in cloudy cornea. (iii) Gonio puncture.

(b) (i) External trabeculotomy (ii) Trabeculectomy

(iii) Trabeculotomy combined with trabeculectomy. (c) Draining devices

(d) (i) Laser

(ii) Cryo

(iii) Ultrasound

(a) (i) Goniotomy. Goniotomy is the preferred surgical procedure for all buphthalmic eyes where surgery is indicated. This is a highly skilled microsurgical procedure done through a suitable operating gonioscope under general anaesthesia. It can be done between one month to two years with excellent result. The success rate falls with increasing age. It is less effective after three years. In this procedure a fine specially designed goniotome is introduced in the anterior chamber via a peripheral corneal stab incision under operating gonioscope and operating microscope. The superficial layers of one-fourth circumference of trabecular meshwork are cut just below the Schwalbe’s line. Some eyes may require repeat surgery.

Prior to surgery, intraocular pressure is lowered to a safe limit by oral acetazolamide 15 mg/kg in divided doses. The pupil is constricted by local pilocarpine. It is a very safe procedure in competent hands, some surgeons prefer to do bilateral surgery. It is claimed that only complication during goniotomy is anaesthesia induced. This type of goniotomy is not possible in cloudy cornea.

(ii) Direct goniotomy. This is a less accurate method of opening the trabecular meshwork. This is done in presence of cloudy cornea. The goniotomy knife is passed almost

blindly across the anterior chamber to reach the trabecular meshwork on the opposite side. The superficial meshwork is cut as in classical goniotomy. This method is less effective and produces more complications.

(b) (i) External trabeculotomy is a procedure where the conjunctiva is incised and reflected to expose the sclera near the limbus. A vertical scletotomy is done to reach the canal of Schlemm. The canal is divided, the two cut ends are identified. A specially designed trabeculotome is passed in the canal. Once whole length of the trabeculotome has gone inside, the trabeculotome is swept in the anterior chamber ripping open a passage in the trabecular meshwork. The procedure is less effective than goniotomy. It is not suitable for advanced case where due to altered surgical anatomy of the limbus, it is difficult to identify the canal of Schlemm.

(ii) Trabeculectomy. Trabeculectomy is more successful in moderately advanced cases does not require special device like goniotome, operating gonioscope or trabeculotome.

The difficulty arises due to changed anatomy of the surgical limbus. A sclerotomy wound may be inadvertently placed too posteriorly, resulting in injury to the ciliary body, loss of vitreous, the lens may be injured during the procedure. The advantage of the method is that it can be done in presence of hazy cornea.

Thermal sclerotomy, iris inclusion surgery, corneo scleral trephine, cyclodialysis which were done in past have been given up in favour of trabeculectomy. trabeculectomy with use of anti metabolities is said to give better results.43

C. Artificial drainage device44 or aqueous drainage device (A.D.D.)44. These are miniature artificial drainage devices that45 are transplanted under the Tenon’s capsule to bypass the trabecular meshwork and canal of Schlemm. They are generally used in advanced glaucoma or where previous surgeries have failed. There are three types of glaucoma devices, the first two are of historical importance and are no more in use the devices are :

(a) Seton, (b) Shunts, (c) Valves.

(a) Seton. This is a solid rod. One end of which is introduced in the AC and the other end is anchored under the subconjunctival tissue. The aqueous drains by the side of rod by capillary action. The drainage is uncontrolled.

(b) Shunt. This is a tubular structure one end of which rests in the anterior chamber. The fluid passes through the lumen passively. This is also uncontrolled.

(c) The valves. These are tubular structures similar to shunts, have one-way flow from anterior chamber to sub-Tenon’s space. The flow is regulated, once the tension falls below a critical level the flow stops.

These devices are seldom used as primary procedure. They are used only in eyes where other surgical procedures have failed.

These devices are associated with high risk of intraoperative and post operative complications.

Common complications of these devices are :

—Perforation of thin sclera.

—Injury to the ciliary body

—Vitreous loss

—Endothelial damage during insertion

—Intra operative hyphaema

—Expulsive haemorrhages

—Persistent shallow AC

—Corneal decompensation

—Tube touching the iris

—Moderate to severe uveitis

—Closure of the lumen

—Extrusion of the device

Laser in buphthalmos. Q switched Nd-YAG has been used to produce laser goniotomy, otherwise laser is mostly used as cyclo destructive procedure. Either transscleral or through pupil46. Transscleral Diode or Nd-YAG is used to ablate ciliary body as cyclo destructive procedure. Argon or Nd YAG is also used to open the clogged end of aqueous drainage device. Laser is also used to make extra iridotomies if need arises.

(a). Medical treatment. Medical treatment have limited role in management of primary buphthalmos. Miotics, the drug used widely in adult wide angle glaucoma is only used to constrict the pupil before glaucoma surgery or iridotomy. It is claimed that pilocarpine may cause paradoxical rise of tension due to collapse of trabecular meshwork because of high attachment of uvea in posterior meshwork42. Beta blockers, alpha agonist should be used in consultation with paediatrician. Acetazolamide and IV Mannitol is seldom required.

(b). Ancilliary treatment. This is divided into two main parts :

1.Correction of existing error of refraction.

2.Utilising salvageable vision by low vision aids.

1. The buphthalmic eyes are generally myopic with astigmatism. There may be a change in refractive power following surgery, mostly astigmatism. In uniocular cases amblyopia sets in early and if not managed becomes permanent, vision with best corrected glasses is rarely normal due to corneal opacity, irregular astigmatism, optic nerve changes, residual glaucoma and amblyopia.

Complication in buphthalmic eyes :

A.First and foremost complication is missed diagnosis. Either the glaucoma is mistaken as simple epiphora or conjunctivitis or these conditions are mixed up as glaucoma and the child exposed to unnecessary investigation. The later is a better option. In all cases of buphthalmos occult retinoblastoma should be suspected and excluded. The child must be examined with an indirect ophthalmoscope and if needed an ultrasound may be ordered.

B.Amblyopia squint and nystagmus are common both in treated as well as untreated eyes.

C.Persistent lacrimation and photophobia may be seen even when tension has been brought under control.

D.Large equatorial staphylomas are seen in untreated or poorly managed cases. The thin sclera is prone for rupture that may lead to bleeding, warranting removal of eye.

E.Subluxation and dislocation of clear or cataracts lens are occasionally seen.

F.The buphthalmic eyes generally have high axial myopia hence they are prone for retinal detachment.

Associated and secondary congenital glaucomas32. A heterogeneous group of congenital anomalies of eye with or without systemic manifestation produce glaucoma in children.

They are :

A.Associated causes of congenital glaucoma. In contrast to primary congenital glaucoma where the pathology lies in the trabecular meshwork with normal cornea and iris. The associate glaucoma’s may or may not have abnormality in the trabecular meshwork.

B.The other group consists of few primary conditions that cause secondary glaucoma. These are :

1. Congenital uveitis

2. Congenital keratitis

3. Intrauterine trauma

4. Neoplasm

A.The associated causes of congenital glaucoma is long. Some of the causes are :

1.Iridocorneal dysgenesis (see page 337)

2.Mesodermal dysgenesis (see page 338)

3.Congenital anomalies of uvea :

(a) Aniridia

(b) Congenital ectropion of uvea

4.Congenital anomalies of globe (a) Microphthalmos

(b) Nanophthalmos

5.Congenital anomalies of posterior segment

(a) Persistent primary hyperplastic vitreous (b) Retrolental fibroplasia

6. Phacomatosis

(a) Struge Weber syndrome (b) Neurofibromatosis

7. Miscellaneous

(a) Lowe’s syndrome (b) Nevus of ota

(c) Mucopolysaccharidosis

Most of the common conditions have been discussed in various chapters except congenital ectropion of uvea, glaucoma in Lowe’s syndrome and nevus of ota.

Congenital ectropion of uvea47. This is non progrgessive, unilateral condition. The pupil is circular, react well to light and accommodation. In normal eyes there is no pigment in the stroma, in this condition iris pigments are present in anterior stroma. Glaucoma is caused due to maldevelopment of angle of anterior chamber. Glaucoma develops in childhood or during puberty. The condition may be associated with neurofibromatosis.

Glaucoma in Lowe’s syndrome. Lowe’s syndrome is a systemic disorder that involves not only eyes but multiple organs. The ocular manifestation are bilateral congenital cataract, glaucoma, iris atrophy, miosis, microphthalmos. Glaucoma is bilateral in one third of cases. Female carriers have cortical lenticular opacity. Management of glaucoma is difficult, goniotomy may help. Cataract and glaucoma are independent of each other. The systemic involvement consists of mental retardation, renal ricket, aminoaciduria and hypotony48.

Nevus of ota. In this condition, there is deposition of melanocytes in the skin, and conjunctiva. This is generally an isolated congenital anomaly or may be associated with nevus of skin on the distribution of second and third division of the trigeminal. Besides melanosis bulbae a small percent of cases develop glaucoma on the side of malanosis. The pigments obscure scleral spur and ciliary band, the trabeculum may be fragmented.46

Glaucoma in older children. Glaucoma in children fall in following broad groups :

A.True congenital glaucoma, diagnosed between birth and first three months.

B.Infentile glaucoma1 is between three months to three years.

C.Juvenile glaucoma1 seen over three years of age.

Juvenile glaucomas form a large group of conditions of diverse cause that results in rise of intraocular tension. These are either :

1.Late manifestation of congenital glaucoma

2.Early onset of adult chronic simple glaucoma.

3.Secondary glaucoma

(a) Wide angle (b) Narrow angle

Common causes of junevile glaucoma are :

1.Associated congenital glaucoma29,30, may be hereditary or non-hereditary.

2.Trauma

3.Uveitis

4.Steroid induced

5.Post surgical status

6.Phacogenic

7.Tumour related

8. Other less common glaucomas seen in children are : (i) Neovascular glaucoma

(ii) Glaucomatocyclitis crisis (iii) Epidemic dropsy

From the above list of causes it is obvious that except juvenile open angle glaucoma, all other glaucomas are secondary to local or systemic causes. Most of them are wide angle. Presenting signs, symptoms and management of these glaucomas are identical to adult glaucoma.

Traumatic glaucoma in children49

All kinds of trauma mechanical, physical, chemical, radiation can result in raised intraocular tension in all ages. As trauma is more common in male children, incidence of traumatic glaucoma is more common in boys. Most of the eyes have a initial fall of intraocular pressure following injury, this is most marked following penetrating injury due to obvious reason that the wound acts as a large channel for aqueous to drain. In contusion the hypotension is due to reduced ciliary secretion, which builds up later to reach normal level and may remain so, in some cases there is a delayed rise that may take months or year to manifest. Immediate rise of tension is seen due to large hyphaema, swollen lens, cortical material filling the anterior chamber. In chemical burns the immediate rise of tension is due to shrinkage of outer coat of the eye and release of prostaglandin50.

Post traumatic glaucoma may sometimes be traced to earlier surgical intervention like aphakia, pseudophakia, penetrating keratoplasty, vitrectomy, retinal surgery, laser capsulotomy and laser photo-coagulation.

Post traumatic glaucoma can be divided in following groups : (a) Open globe injury

(i) Accidental (ii) Surgical

(b) Closed globe injury Contusion and concussion

(c) Chemical injuries

Glaucoma in non surgical penetrating injury. Immediately after penetration of the globe, the eye goes soft due to the open wound draining constantly at a very high rate. If the wound does not close, the eyes goes into a state of perpetual hypotony, phthisis and blindness. If the wound is repaired surgically or heals by natural process, the intraocular pressure builds up. If there is not much of tissue disruption, the intraocular tension remains within normal range, only on rare occasions the tension may rise after months or years.

The tissue disruption following penetrating injury and subsequent repair may lead to secondary angle closure, formation of peripheral anterior synechia, pseudo-angle- formation, fibrosis of trabecular meshwork and obliteration of canal of Schlemm.

There may be pupillary block due to swollen lens, after cataract, occlusio pupillae, seclusio pupillae, iris bombe, cyclitic membrane. The vitreous may finds its way in anterior

chamber or block of angle. Angle closure may worsen pupillary block and vice versa. Associated infection, inflammation may also worsen the condition. An associated retained intraocular foreign body may contribute to rise of tension separately or with uveitis.

Management of glaucoma in penetrating injury. Best management of glaucoma in penetrating injury is to minimise tissue disruption rectify, tissue disruption that is already present, minimise uveitis by use of local and systemic steroids, antibiotics and cycloplegics.

There are two methods of repairing the penetration wound :

1.Repairing of the corneal, scleral and corenoscleral wound with removal of incarcerated uvea, lens and vitreous. A non incarcerated lens may too have to be removed by lensectomy along with anterior vitrectomy. Any retained intraocular foreign body is also removed while doing extensive vitrectomy. The next important step is to reform the anterior chamber, this prevents closure of trabecular meshwork.

2.Primary repair of cornea, scleral wound and excision of incarcerated uvea. This is followed by well planned extensive surgery that include lensectomy, various grades of vitrectomies, removal of foreign body, scleral buckling and reformation of anterior chamber with or without intraocular implant after the primary wound has healed well.

Once the glaucoma sets-in, inspite of best surgical management of penetrating injury, the eye may be put on medical therapy of glaucoma by way of local beta blockers, alpha agonist, carbonic anhydrase inhibitors or systemic carbonic anhydrous inhibitors for short period. Uveitis is treated by steroids and cycloplegic. Miotics and latanoprost are contra indicated. If medical treatment fails or the child does not comply with the prescribed regime, best alternative is to undertake any of standard anti-glaucoma surgeries. Laser may be used to do an iridotomy or iridoplasty. Laser trabeculoplasty generally fails. In some cases an aqueous drainage device may be the last alternative.

Glaucoma following ocular surgery. Both types of surgical wounds i.e. open globe and close globe wounds may lead to secondary glaucoma. Common intraocular surgeries that are associated with glaucoma are :

—Needling, aspiration, lensectomy in congenital and traumatic cataracts.

—Pupillary block in aphakia and pseudoaphakia

—Repair of penetrating injury

—Vitrectomy

—Penetrating keratoplasty

Closed globe surgeries that cause post operative rise of tension are : Scleral bucking

NdYAG posterior capsulotomy

Glaucoma following lens surgery. From the conditions mentioned above it is clear that surgery on lens is a common cause of post operative glaucoma. It can be seen in all ages but more common in children, even a surgery of short duration and minimal handling like needling, aspiration is fraught with rise of tension51 that may be seen between 6% and 24%

eyes. It is also seen in pseudophakia.52, 53 Glaucoma is more common in anterior chamber IOL and iris supported IOL.

Exact cause of glaucoma is not known. Most of the times it is secondary, wide angle glaucoma. The causes are multifactorial. They can be due to one of the following or in combination of more than one factor.

1.Distortion of angle of anterior chamber.

2.Formation of peripheral anterior synecha.

3.Effect of visco-elastic.

4.Pupillary block—Vitreous in the pupillary area, cortical material in pupil.

5.Angle closure

6.Uveitis glaucoma haemorrhage syndrome

7.Pigment dispersal syndrome.

There is initial fall of tension following incision that remains low for first twenty four to forty eight hours and then builds up to normal range and is maintained with in physiological limits. Occasionally there is acute rise of tension following lens surgery, this is due to relatively small eye53 that is prone for angle closure, closure of angle by visco elastic, and obstruction of pupil and angle by cortical material. The vitreous generally does not fill the anterior chamber in congenital cataract but may be liquefied following injury and associated uveitis of long duration. Pupillary block due to vitreous can be prevented if a good vitrectomy is done along with PC IOL in children. A liberal peripheral iridectomy minimises the pupillary block.

An irritable child with chronic redness of the eye, lacrimation, photophobia, should warn against possibility of immediate post lensectomy and IOL related glaucoma. That requires confirmation by measurement of intraocular tension and examination of anterior chamber. In some children there is a delayed rise of tension after years following needling or pseudophakia. This type of glaucoma behaves like a wide angle glaucoma.

Management consists of :

1.Prophylaxis. This includes removal of as much of cortical matter from AC and pupillary area, removal of all viscoelastic from AC, reformation of AC by BSS or air, anterior vitrectomy, peripheral iridectomy. Judicious use cycloplegic and steroid to ward off post operative uveitis.

2.Medical treatment. Local beta blockers, alpha agonist. Miotics and latanoprosts are contra indicated. Systemic carbonic anhydrase inhibitors for a short period gives prompt relief to the child.

3.Conventional filtering surgery. Conventional filtering surgery has not been very effective but use mitomycin C and 5 fluorouracil as adjustment have better prognosis.

4.Laser trabeculoplasty has no role in paediatric aphakia/pseudophakic glaucoma. However laser is used to do post-operative iridotomy and iridoplasty to by pass pupillary block.

5.In intractable glaucoma aqueous drainage device may be the last method.

Uveitis glaucoma hyphaema (UGH). This condition was very common in era of anterior chamber IOL. The AC IOL caused, repeated trauma to the iris that resulted in acute non granulomatous uveitis after months of surgery. It presented as haemorrhagic uveitis with rise of tension. Many factors like 10L itself, ischamia of iris, pressure necrosis of iris, chaffing of iris trigger onset of uveitis. P.C. 10L can also cause UGH if the edge of the lens presses against the ciliary body.

Management consists of active and prolonged treatment of uveitis, hyphaema does not require specific treatment. Glaucoma is initially treated by medical methods, if it fails surgery may have to be restored to.

Glaucoma following vitrectomy. Fortunately few children require vitrectomy. The conditions that need vitrectomy in children are mostly traumatic with or without intraocular lens implant, lost PC IOL and vitreous haemorrhage. It is thought that post vitrectomy glaucoma is seen in about one fifth of the cases. Post vitrectomy rise of intraocular tension is more common when long acting gases are used as temponade. Early rise is caused by expansion of the gases. Silicone oil also causes rise of intraocular tension. Neovascularisation following vitrectomy is another cause of post vitrectomy glaucoma. Management is similar to any open globe post traumatic glaucoma.

Glaucoma following penetrating keratoplasty56. Post penetrating keratoplasty glaucoma is more frequent than diagnosed. Glaucoma following P.K. is a major cause of graft failure. It is more common if PK is associated with lens extraction. Intra capsular lens extraction with penetrating keratoplasty is more formidable combination in producing glaucoma than extra capsular lens extraction. Incidence of glaucoma increases with each repeat surgery. Tight sutures, collapse of trabecular meshwork, small trephine size, donor larger than recipient are probable causes of glaucoma.

Malignant glaucoma (ciliary block glaucoma, aqueous misdirection glaucoma57,58. Malignant glaucoma is a rare but most difficult of secondary glaucoma that has both pupillary block and angle closure. Classically this form of glaucoma results in uniform shallowing of both central and peripheral anterior chamber, small pupil, very high intraocular tension that becomes worse with miotics but may be relieved by cycloplegic. Though spontaneous cases without any provocation have been reported. Commonest situation where it is seen is following intraocular surgery. Paradoxically antiglaucoma filtering surgery heads the list of surgical procedures that cause malignant glaucoma. They are :

1.Glaucoma surgeries. Filtering and fistulous procedures, iridectomy, both types of iridotomies i.e. surgical or laser.

2.Lens surgeries. Needling, aspiration, extra-capsular cataract extraction, intracapsular lens extraction with any type of IOL or without IOL.

3.Repair of penetrating corneal or corneoscleral injuries.

The condition is most commonly seen in incisional procedures following narrow angle glaucoma. Malignant glaucoma is not related to any specific type of glaucoma surgery. Pre operative intraocular tension also does not influence its clinical presentation.

Malignant glaucoma is more common is phakic eyes than in aphakic eyes. Rarely it can be bilateral. There are two mechanisms that work in combination, they are :