CONGENITAL GLAUCOMA&

CONGENITAL CATARACT

DR REGINA LALRAMHLUNI II YR RSO

UPGRADED DEPARTMENT OF OPHTHALMOLGYMYH & MGMMC, INDORE

CONGENI TAL GLAUCOMA

INTRODUCTION

Occurs due to developmental defect in the trabecular meshwork & anterior chamber angle.

Noted by hippocrates

Recognsied by Von Muralt in 1869

Epidemiology

1 in 10,000 births

b/l 65-80%

M:F = 3:2

25% diagnosed as newborn, 60% by 6 months, 80% by 1 year

Genetics

Most are sporadic

10% familial

Maybe autosomal dominant, autosomal recessive or multifactorial inheritance

three major loci (GLC3A, GLC3B, GLC3C) identified on chromosome 2, 1, 14 respectively

TERMINOLOGY

Relating to age of onset:

1. Pediatric glaucoma: is a broad term referring to any form of glaucoma that may occur from birth to 18 years of age.

2. Congenital glaucoma: the glaucoma exists at birth and usually before birth..

3. Infantile glaucoma: occurs from birth until 3 years of life

4. Juvenile glaucoma: occurs after the age of 3 to teenage years

5. developmental glaucoma: if there is associated anomalies, either ocular or systemic

Relating to structural maldevelopment

1. Goniodysgenesis: maldevelopment of irido-corneal angle.

2. Trabeculodysgenesis: maldevelopment of trabecular meshwork.

3. Iridodysgenesis: maldevelopment of iris

4. Corneodysgenesis: maldevelopment of cornea

Figure1: The normal chamber angle: on the left is a histological cross-section; on the right is a drawing of the same

Figure 2: An underdeveloped chamber angle

PATHOGENESIS

- Despite general agreement that abnormal development of the anterior chamber angle obstructs aqueous outflow (isolated trabeculodysgenesis), the exact nature of this abnormality has yet to be understood .

- Barkan initially postulated an impervious membrane over the trabecular meshwork k/as barkans membrane but it was disproved histopathologically.

Maumenee demonstrated developmental arrest of the iris and ciliary muscle(longitudinal and circular fibers) in the seventh month of gestation causes the insertion of the iris and ciliary body in an anterior location,over-lapping the trabecular meshwork.

Anderson provided histopathological support for the high insertion of the iris into TM

The trabecular meshwork has also been noted to have thickened trabecular beams and uveal cords,with narrowed trabecular spaces lead to impaired trabecular outflow.

Shaffers-weiss classification

Hoskins classification

Causes of visual loss

- Corneal scarring / irregular astigmatism- Cataracts- Optic nerve damage- Anisometropic amblyopia - Strabismic amblyopia - Retinal pigmentary changes,detachment (possible

complication after filtration ,seton,or cycloablative surgery)

Clinical features

Symptoms:-

A clinical triad of photophobia , epiphora , and blepharospasm is commonly associated with the presentation of primary congenital glaucoma

Others- cloudy cornea, enlarged cornea or eye, irritability, red eye, poor vison, pain.

-Tear in the descemet’s membrane (Habb’s striae result from new basement membrane laid down by the endo. cells) ,which are single or multiple, oriented horizontally or concentric to the limbus associated with corneal edema in the early phases& have a significantly lower endothelial count.

- In severe cases Acute hydrops may occur.

signs

-Corneal enlargement is a very specific sign of PCG (Till 1st 3 yrs)

sclera also expands slowly(till ten yrs) under the influence of increased intraocular pressure and thinning brings about increased visibility of the underlying uveal tissue in neonates and causes the blue sclera

- In advanced cases ,the zonules may become stretched and rarely the lens may subluxate .

- Enlargement of the eye occurs under the influence of elevated intraocular pressure with major enlargement occurring at the corneo-scleral junction .

- As the axial length of the globe increases ,myopia and astigmatism occur.

- Cupping of the optic nerve proceeds more rapid and more likely to be reversible if IOP is normalized . The younger the child, the faster this reversibility

- symmetrical cupping has been attributed to stretching of the optic canal and backward bowing of lamina cribrosa .

- In eyes of young glaucoma patients there is often generalized enlargement of the optic cup with preservation of an intact neuroretinal rim.

- Hyphema,RD and Pthisis bulbi are often the final outcome of untreated or refractory glaucoma.

Management of Congenital Glaucoma

Initial Evaluation

Office examination – Following can be performed in children more than 5 year of age-

• Slit lamp examination• Applanation tonometery• Gonioscopy • Optic nerve evaluation• Retinoscopy• Kinetic Goldman visual field testing(with the assistance

of patient and encouraging perimeterist)

Examination under anaesthesia

• General anaesthesia is usually required for thorough examination of children under the age of 5 years.

• Its sequential components consist of : -IOP measurement -Cornea assessment -Gonioscopy -Ophthalmoscopy -Additionally axial length

measurement, UBM or cycloplegic Retinoscopy

IOP and tonometery

• Most reliable IOP are obtained under intramuscular ketamine.

• Perkins tonometer and Tonopen are reliably used to measure IOP in children

• Infant and young children appear to have IOP lower than those expected in adults

• Mean IOP of 9.59 mm of Hg is found in the newborn which rises to 13.95 by 7 or 8 year of age

• Infant with primary congenital glaucoma may present with IOP exceeding 30 –40 mm of Hg if unanesthetised, but may be much lower under the influence of inhalational anesthesia

Corneal diameter measurement

•An effective measurement of the corneal diameter can be obtained using calipers to measure the horizontal diameter from the first appearance of the white scleral fiber at the limbus on one side to the same point on the other side, from the 9 o’clock to 3 o’clock position

•Measuring the horizontal corneal diameter is a fundamental part of childhood glaucoma assessment

•A horizontal corneal diameter of 12 mm in the first year of life associated with corneal oedema is pathognomic of glaucoma

Gonioscopy

Ideally a smooth domed Koeppe 14-16 mm lens with a Barkan light and hand- held binocular microscope is utilized for the purpose

A Goldmann goniolens is also used for viewing the angle through the operating microscope

If marked corneal clouding exists the view may be improved by using topical anhydrous glycerin or70% alcohol or 10% cocaine on a cotton tipped applicator

If necessary, edematous epithelium may also be removed using a surgical blade

Gonioscopic anatomy of normal infant eye

- Iris inserts posterior to the scleral spur

- Flat iris insertion due to poor development of the angle recess till 6 to 12 months

- Ciliary body band is distinct in most cases

- TM appears thicker and more translucent than in adults

Gonioscopy of the eyes in infant with primary congenital glaucoma reveals –

- Anterior insertion of the iris directly into the trabecular meshwork

- Stippled trabecular meshwork surface

- trabecular meshwork appear thicker than normal

- Peripheral iris shows thinning of the anterior stroma

- Angle is usually devoid of vessels although root of vessels from the major arterial circle is seen above the iris surface and has been referred to as Loch Ness Monster phenomenon

- The peripheral iris inserting into the trabecular meshwork may appear translucent and is referred to as the Lister’s morning mist

Ophthalmoscopy

Optic nerve cupping occurs rapidly in infant with elevated intraocular pressure and unlike in adult eyes, is also rapidly reversible with normalization of intraocular pressure

Persistent IOP elevation, however, causes glaucomatous optic atrophy due to loss of ganglion cells

C/D ratio greater than 0.3 are rare in healthy infant and should cause suspicion of glaucoma

Structural defect

• Isolated trabeculodysgenesis are highly responsive to both goniotomy and trabeculotomy ab externo

• In iridotrabeculodysgenesis success rate for goniotomy and trabeculotomy decreases, multiple surgeries needed. Trabeculotomy is initial better procedure of choice

• In iridocorneotrabeculodysgenesis prognosis for surgical treatment is poor. Ab externo combined trabeculotomy and trabeculectomy may be useful as initial procedure

Medical therapyB - blockerTimolol : is the most widely used beta blocker in children

It has been reported that plasma timolol level; after treatment with 0.25%timolol in children far exceeds adult plasma level, treated with 0.5%timolol

Reduction in heart rate, exacerbation of asthma and apnea has been reported in 4-13%of children treated

Avoided in neonates and the premature due to risk of sleep apnea

When indicated, timolol gel forming solution preferred due to lesser systemic absorption

Carbonic anhydrase inhibitors

- Temporary measure to reduce IOP and corneal edema prior to surgery

- Doses 5-10 mg/kg/day in divided dose- Serious side effects include growth suppression, metabolic acidosis,

drug idiosyncrasy, bone marrow suppression. Thus prolonged therapy is avoided

- Currently topical dorzolamide is preferred and administered 2-3 times daily

- Combination therapy of timolol and dorzolamide may be used in older children with no contraindication

Alpha receptor agonistsNot recommended in children under 18 yearsCross immature blood brain barrier and causes adverse

CNS effect -slight drowsiness, respiratory depression, failure of recovery from anaesthesia and death of premature infant

Prostaglandin analogues- effective but may cause ocular hypotension

Cholinergic drug (Pilocarpine)No role in congenital glaucomaMay be useful in children with glaucoma in aphakia and

pseudophakia with open iridocorneal angle

Surgical treatment

Goniotomy

Procedure of choice in eyes with congenital glaucoma with corneal edema and minimum ocular and corneal enlargement

Initially practiced by Barkan

Aims to remove the obstructing tissue in the angle causing resistance to aqueous flow

Prerequisites – General anaesthesia, operating microscope, contact lens (e.g.. Barkan lens), tapered goniotomy blade

Procedure:-Preoperative pilocarpine instillation help to open the angle

Inner portion of the nasal trabecular meshwork over 90-120 degree is incised

Mild hyphaema on withdrawal of knife indicate correctly placed incision

Mechanism of action-Relieves the compressive traction of anterior uvea on the

meshwork-Eliminate any resistance imposed by incompletely

developed inner meshwork

AdvantagesLess traumaticSafe Rapid Can be repeatedSpare the conjunctiva for possible later surgery

Disadvantages

- Procedure not possible if media hazy

- Require special instrument

- Need experienced surgeon

- Possibility of corneal endothelial, angle and lens trauma

- Moorefield experience showed 20% relapse rate over a 30 year period with no peak age of relapse,life long follow up necessary

- Best prognosis for infant presenting between 2-8 months of age

- Worst prognosis with elevated pressure and cloudy cornea at birth

Trabeculotomy

Procedure of choice; when cornea is opaqueAb externo procedureIdentify schlemm canal by external approachAs favorable as initial goniotomy procedure

ProcedureLimbal or fornix based conjunctival flap is made

scleral flap is fashioned and schlemm’s canal is located by slowly deepening a 2mm radial incision placed at the corneoscleral junction

Junction of the blue white sclera mark the location of scleral spur; schlemm’s canal is a mm anterior to the scleral spur

Trabeculotome is gently threaded into the canal and swept into anterior chamber, rupturing the internal wall of schelmm canal and trabecular meshwork

It directly exposes it to aqueous humour

Procedure repeated to the other side of canalScleral flap is tightly closedAccurate localization of the schlemm canal is the most important stepMild to moderate hyphaema confirm accurate identification of the

schlemm canal Appearance of aqueous is also evidence of entry into the schlemm

canal

AdvantagesCan be performed in opaque corneaHigher success rate when combined with trabeculectomy

Disadvantages Difficult visualization of angle structure; sometimes leading to serious

complicationPotential complications include DM stripping, iris prolapse, iridodialysis,

cyclodialysis with persistent hypotony, false passages, lens subluxation, flat anterior chamber

Also damages conjunctiva decreasing success of further filtering surgery

Trabeculectomy

indications:- visual potential, unscarred conjunctiva, faithful follow up- unlikely to respond to angle surgery- very low target pressure required- secondary glaucoma

Combined trabeculotomy+ trabeculectomy

indications:- Failure to cannulate Schlemm's canal- Failed previous angle surgery (<=2 gonio or

trabeculectomy)- Primary procedure

Procedure:- Trabeculotomy creates a direct continuity between AC &

Schlemm's canal & trabeculectomy helps aqueous humor bypass Schlemm's canal to be drained out of AC to maintain normal IOP

- Superior in controlling IOP

MANAGEMENT OF REFRACTORY PEDIATRIC GLAUCOMAS

- filtration surgery with anti-fibrotic drugs- glaucoma drainage implants- cyclodestructive procedure

Role of anti-metabolites:

success rate

Mitomycin C commonly used

Applied to area of bleb beneath conjunctiva

Thorough wash before entering AC

Drainage shunts

Indications:

- Failed trabeculectomy- High risk of complication with filtration surgery( Sturge weber

syndrome)- Scarring ( after multiple conjunctival surgeries)

non restrictive flow restrictive-molteno implant - Ahmed valve-Baerveldt implant - Krupin valve

Cyclodestructive procedures:

- cyclophotocoagulation( transscleral Nd:YAG , transscleral diode, endoscopic diode)

- cyclocryotherapy

Success rate : 30%1800 treated first to decrease risk of hypotony

Long term follow up and prognosis

Degree of relief from photophobia, tearing and blepharospasm usually reflect the effectiveness of surgery

Patient should be followed up between 3 and 6 months of surgery

Should be examined periodically and for indefinite time

CONGENITALCATARACT

DEFINITION

CONGENITAL CATARACT:- Disturbance in the normal growth of the lens before birth

DEVELOPMENTAL CATARACT:- Occur from infancy to adolescence Infantile-present at 1 year Juvenile- developed later

Important facts

• 33% - idiopathic - may be unilateral or bilateral• 33% - inherited - usually bilateral• 33% - associated with systemic disease - usually bilateral• Other ocular anomalies present in 50%

ETIOLOGY

1. Heredity: usually dominant. about 1/3

2. Maternal factors: -malnutrition-infections-drugs ingestions-radiation

3. Foetal or infantile factors-deficient oxygenation-metabolic disorders-ass. with other congenital anomalies(lowes syndrome

myotonic dystrophica, congenital ichtyosis)-birth trauma-malnutrition

4. idiopathic

CLINICAL TYPES

- involves central part of anterior capsule and adjoining superficial most cortex

- due to delayed development of anterior chamber- due to corneal perforation

ANTERIOR POLAR CATARACT

1. thickened white plaqued

2. Anterior pyramidal cataract: capsular opacity is cone shaped with its apex towards cornea

3. Reduplicated cataract(double cataract): along with central point of anterior capsule, lens fibre lying immediately beneath is opaque and subsquently separted from capsule, laying transparent fibre in between

POSTERIOR POLAR CATARACT

Maybe associated with- persistent hyaloid artery remnants( Mittendorf dot)

- posterior lenticonus

- persistent hyperplastic primary vitreous

NUCLEAR CATARACT

1. cataracta centralis pulverulenta

-invlolves embryonic nucleus-small rounded opacity lying in the centre of lens-has a powdery appearance

2. total nuclear cataract

- involves embryonic and fetal nucleus and somtimes infantile- chalky white central opacity

LAMELLAR OR ZONULAR CATARACT

-Occurs in the zone of foetal nucleus

- The main mass of the lens internal and external to the zone of cataract is clear, except for small linear opacities like spokes of wheel (riders)

SUTURAL AND AXIAL CATARACTS

- Series of punctate opacities scaterred around the anterior and posterior Y sutures present in the foetal nucleus

1. Floriform cataract- arranged like petals of flowers

2. Coralliforem cataract - arranged in the form of coral

3. Spear shaped cataract- in the form of scattered heaps of shining crystalline needles

4. anterior axial embryonic cataract- as fine dots near the anterior Y suture

BLUE DOT CORTICAL CATARACT

- cataracta punctata caerulea

- as rounded bluish dots situated in the peripheral part of adolescenct nucleus and deeper layer of cortex.

CORONARY CATARACT

- involves either adolescent nucleus or deeper layer of cortex

- regular radial distribution in the periphery of lens encircling the central axis.

MEMBRANOUS CATARACT

- total or partial absorption of cataract leaving behind thin membranous cataract

CONGENITAL CAPSULAR CATARACT

1. Anterior capsular cataract- nonaxial, stationary and visually significant

2. posterior capsualr cataract- rare and can be ass with persistent hyaloid artery remnants.

DIAGNOSIS

-Leukocoria-Strabismus-Nystagmus-Photophobia

O THER CAUSES O F LEUKO CO RIA-Retinoblastoma-Toxocariasis-Coats disease-ROP-PHPV-Retinal detachment-Coloboma-Retinal dysplasia-Norrie's disease

EXAMINATION PROTOCOL IN PAEDIATRIC CATARACTS

HISTORY:1. Duration2. F/H of congenital cataract3. Visual status4. Behavioural Pattern and School Performance

BIRTH HISTORY:

1. H/O of maternal infection in 1st trimester2. Gestational age and birth weight3. Birth Trauma 4. Supplemental oxygen therapy in perinatal period5. Developmental Milestones

OCULAR EXAMINATION:

1. Visual acuity and fixation pattern2. Refraction3. Cover-uncover test (Hirschberg's)4. Note nystagmus if any5. Slit lamp examination

-associated congenital anomalies of iris,lens-type of cataract-iridodonesis/phacodonesis

6. Tension applanation if possible7. Fundus examination if possible8. BScan USG if there is no fundus view

LABORATORY INVESTIGATION

- intrauterine infection viz toxoplasmosis, rubella, cytomegalovirus and herpes virus by TORCH test

- galactosemia by urine test, for reducing substance, red blood cell transferase and galactokinase levels

- Lowe's syndrome by urine chromatography for amino acids

- Hyperglycemia by blood sugar

- Hypocalcemia by serum calcium and phosphate levels and x-ray skull.

IMPORTANT POINTS REGARDING MORPHOLOGY

Visually significant: nuclear, lamellar, posterior, total, membranous

Progressive: posterior lenticonus, PHPV, lamellar,subcapsular

Most common: lamellar

Best visual prognosis: anterior, sutural, posterior lenticonus

DECISION FOR SURGERY IS DEPENDENT IN THESE FACTORS

Morphology and location of cataract

Size and density of the opacity

Laterality

Visual behavior of the infant

Presence of associated ocular abnormalities

MORPHOLOGY AND LOCATION OF CATARACT

-The more central and the more posterior the location of the opacity, the more visualy significant the cataract will be

- Nuclear cataracts degrade vision more than lamellar cataracts

SIZE AND DENSITY OF CATARACT

- More than 3mm dense central opacity is significant and need surgery

- In incomplete bilateral cataracts, density is more important than the size of opacity

- If major retinal vessels can not be seen through the cataract surgery is indicated

- Semi-transparent opacity should be treated conservatively

LATERALITY

- If a child with unilateral or bilateral cataract develops strabismus, surgery must be done as soon as possible.

- In partial unilateral cataract, pupillary dilatation combines with amblopic therapy is an alternative for surgery.

- If a child with bilateral cataract develops nystagmus, surgery is indicated, although visual prognosis is generally poor.

VISUAL BEHAVIOR

- Ability to fixate the light or follow motions

- Visual attention

- Pupillary reflex: RAPD is poor prognostic sign

- Ability to pick up small objects

TIMING OF SURGERY

- Dense cataract, surgery must be done before age of 6 weeks in unilateral cases

- Dense cataract, surgery must be done before age of 10 week in bilateral cases

- Interval between surgery of the two eyes should be minimised

- Surgerybefore 4 weeks of life will increase risk of glaucoma and pupillary membrane

- Some authors advocate surgery on both eyes simultaenously in selected cases

MANAGEMENT

-Mangement of both anterior and posterior capsules had markedly improved visual results.

-CCC technique provides additional safety and facilities in-the-bag fixation

-Posterior capsulotomy with anterior vitrectomy or posterior CCC is helpful in decreasing the incidence of PCO in the central visual axis

SURGICAL TECHNIQUE

Wound Construction:- a self-sealing corneal tunnel incision with a relatively long internal

entry preferable.

- this technique helps to decrease iris prolapse.

- most children rub their eyes postoperatively; therefore it is prudent to use a suture in SICS.

Increased intravitreal pressure: - high intravitreal pressure may be produced as a result of scleral

collapse due to the the typical low scleral rigidity in children.

- intravitreal pressure is more significantly elevated in eyes with large incision than small incision

Anterior capsulotomy:- to achieve a smooth continuous capsular tear is to perform a skilled

manual CCC

- one alternative to the manual CCC is the creation of a vitrector mediated anterior capsulotomy.

Removal of lens substance: - Hydrodissection helps to ensure max removal of lens cortex and cells

from the equatorial region.

- It is highly recommended in paediatric cataract to aspirate the lens matter with the use of two port irrigation and aspiration to remove cortex completely.

Posterior capsule management:- Since the intact post. capsule opacifies rapidly in children, post capsulorrhexis is preferred by most surgeons.

- post. capsule is thinner and inelastic than ant. capsule capsulorrhexis smaller than ant. CCC is done.

Anterior vitrectomy:- to reduce PCO post CCC with ant. vitrectomy is preferred.

- However, one should recognise the possibility of an increased risk of RD or CME

IOL implantation: - IOL should be placed in the bag rather than the ciliary

sulcus to prevent pupillary capture and IOL decentration.

- Foldable IOL are now being used for paediatric eyes because of reduced incidence of PCO and ability to be inserted through a small incision.

GUIDELINES FOR CHOICE OF IOL POWER

Childre n le s s tha n 2 y e a rs o ld : do biometry and undercorrect by 20% 0r

use axial length measurements only if axial length 17mm - 25D

18mm - 24D 19mm - 23D 20mm - 21D 21mm - 19D

Childre n be twe e n 2 a nd 8 y e a rs o lddo biometry and undercorrect by 10%

COMPLICATIONS

The propensity for post operative non specific inflammation is the reason that the risk of postoperative complication is higher in children

- post. capsule opacification- uveitis- pupillary capture- glaucoma

CORRECTION OF APHAKIA

IOL Implantation:- it is perfectly safe and acceptable in to perform primary implantation in child

older than 1 year- in children younger than 1year IOL Implantation is controversial- a foldable IOL is the most biocompatible IOL as of today

Contact lens: - If IOl is not implanted, contact lenses are given as early as possible to prevent

stimulus derprivation amblopia- overcorrection of +2 to +3D is mandatory.- Silicon lenses or soft hydrogels are well tolerated

Spectacles:- in bilateral cataract, spectacles are better tolerated- a secondary strabismus may be manipulated by prismatic effect of spectacles.- bifocal should be prescribed when the child starts school.

POST SURGICAL TREATMENT

-Evaluation of fixation behaviour-Refraction in each visit-Periodically IOP measurement under GA-In unilateral cataract, occlusion of the fellow eye 50 to 70%

of working hours

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