Ординатура / Офтальмология / Английские материалы / Oxford American Handbook of Ophthalmology_Tsai, Denniston, Murray_2011

626 CHAPTER 18 Pediatric ophthalmology

Table 18.25 Causes of congenital and presenile cataracts

CONGENITAL CATARACT: MANAGEMENT 627

Congenital cataract: management

Timing of surgery

Remove visually significant cataracts as early as possible. Significant unilateral congenital cataracts require urgent removal with optical correction in the first 4–6 weeks of life; significant bilateral congenital cataracts should be removed in the first 8 weeks of life. If cataracts are bilateral, remove both consecutively within a few days of each other.

Procedure

Debate continues over the procedure of choice and when to use implantable lenses. In younger children (<2 years), it is most common to perform a mechanical lensectomy–vitrectomy. In older children, an anterior continuous curvilinear capsulorhexis may be performed with a view to implanting a lens.

Posterior capsular opacification is universal under the age of 6 years, so perform a posterior capsulorhexis and shallow anterior vitrectomy (anterior or pars plana approach). Suture (absorbable) to close the incisions.

There is considerable debate over the estimation of IOL power in children undergoing cataract surgery.

Postoperative care

Excellent postoperative care requires highly motivated parents, coordinated orthoptists and ophthalmologists, and regularly updated refractions.

While contact lenses have many theoretical advantages (particularly in aphakia), their use may be problematic, particularly in younger children. Increased implantation of IOLs results in smaller refractive errors that can be easily corrected by spectacles Older children (≥3 years) benefit from bifocal lenses with an add of +3.00 for near.

In unilateral cases, patching of the unaffected eye is essential. Aggressive patching improves the visual outcome in the operated eye but increases the amblyopic risk to the normal eye. Close monitoring is a priority whichever regimen is used. Parental education preand post-surgery is essential.

Postoperative complications

These include anterior uveitis, posterior capsular opacification, lens reproliferation (e.g., Soemmerring ring), secondary pupillary membranes, glaucoma (especially if aphakic), retinal detachment (often years later), contact lens problems, and unpredictable final refraction.

628 CHAPTER 18 Pediatric ophthalmology

Uveitis in children

Although uveitis is much less common in children than in adults, it is still a significant cause of ocular morbidity. This is most marked in the context of the silent anterior uveitis of juvenile idiopathic arthritis, which accounts for up to 80% of all childhood uveitis. However, it is important to recognize that most other types of uveitis may also affect children.

Juvenile idiopathic arthritis (JIA)

JIA is defined as idiopathic arthritis of >6 weeks duration with onset before 16 years of age. It may be subclassified into systemic, oligoarthritis (≤4 joints), RF-negative polyarthritis (>4 joints), RF-positive polyarthritis, psoriatic, enthesitis-related, and other/overlap syndromes.

The term juvenile idiopathic arthritis replaces juvenile chronic arthritis (JCA) and juvenile rheumatoid arthritis (JRA). Of those with JIA, 20% will develop anterior uveitis, of which 70% will be bilateral and 25% will be severe sight-threatening disease. JIA is more common in females.

Clinical features

Ophthalmic

•Asymptomatic, rarely floaters, dVA from cataract.

•White eye, small KPs, AC cells/flare, posterior synechiae, vitritis, CME (rare); complications include band keratopathy, cataract, inflammatory glaucoma, or phthisis bulbi.

•Arthritis: oligoarthritis, polyarthritis, psoriatic type, or enthesitis related.

•Systemic: fever, rash, lymphadenopathy, hepatosplenomegaly, serositis.

Screening

Patients diagnosed with JIA should be seen as soon as possible by an ophthalmologist. If ophthalmic examination is normal, regular follow-up is indicated according to risk.

Treatment

The treatment goal is to control the uveitis with topical steroids and mydriatic; if systemic therapy is required, this should be done with the help

Table 18.26 Summary of recommendations for evaluation of JIA by ophthalmologists

UVEITIS IN CHILDREN 629

of a pediatrician or rheumatologist. NSAIDs and steroid-sparing agents such as methotrexate are commonly used to minimize side effects.

In long-standing uveitis chronic breakdown of the blood–aqueous barrier leads to persistent flare; AC cells are thus a better guide to disease activity.

Other causes of uveitis in children

The clinical features, investigation, and treatment of these conditions (Table 18.27) are discussed under Uveitis (pp. 313–372).

Treatment

While there are many similarities to adult disease, the following should be noted:

•Children are still growing: systemic steroids reduce growth rate and final height; topical steroids may have systemic side effects and also increase IOP and lead to cataract formation.

•Children are smaller: all treatments should be appropriately titrated to body size and weight.

•Children have longer to live: they are at higher risk of delayed complications (e.g., post-immunosuppression malignancies).

Table 18.27 Uveitis in children

630 CHAPTER 18 Pediatric ophthalmology

Glaucoma in children

The childhood glaucomas are a significant cause of blindness in children but may be missed, being both rare and insidious. Unfortunately, the terms congenital, infantile, and juvenile are often used incorrectly and interchangeably, thereby rendering the nomenclature confusing. Classifying childhood glaucoma by etiology may therefore be more useful.

Causes

Primary (primary congenital glaucoma, trabeculodysgenesis)

In this rare syndrome (1/10,000 live births), angle dysgenesis causes reduced aqueous outflow. It is usually sporadic, but 10% of cases are familial. Genes identified include GLC3A (Ch2p), GLC3B (Ch1p), and GLC3C (Ch14q), all of which result in autosomal recessive disease.

Secondary

Anterior segment dysgenesis, (p. 635)

Developmental abnormalities of the anterior segment result in a spectrum of anterior segment anomalies, including Axenfield–Rieger syndrome, and Peter’s anomaly, and associated abnormalities of the drainage angle. Glaucoma occurs in about 50% of cases.

Aniridia

In aniridia (also called iridotrabeculodysgenesis), the iris tissue is abnormal or absent and is associated with glaucoma in up to 75% of patients.

Lens or surgery related

Surgery for congenital cataracts is associated with glaucoma in up to 40%, being highest for early total lensectomy.

Posterior segment developmental abnormalities

Persistent fetal vasculature syndrome and retinopathy of prematurity may cause glaucoma by a secondary angle-closure mechanism.

Tumor related

Tumors may cause iIOP by reduced aqueous outflow (mechanical, clogging of trabecular meshwork by cellular debris, or secondary hemorrhage). Tumors may be anterior (e.g., juvenile xanthogranuloma), posterior (e.g., retinoblastoma), or systemic (e.g., leukemia).

Phakomatoses

Sturge–Weber syndrome is associated with ipsilateral glaucoma in up to 50% of patients, being highest when the nevus flammeus involves both upper and lower lid. Neurofibromatosis also carries an increased risk, particularly in the presence of an ipsilateral neurofibroma.

Connective tissue disease

Marfan syndrome, homocystinuria, and Weill–Marchesani syndrome are associated with glaucoma. This may arise from abnormal trabecular meshwork or lens block.

632 CHAPTER 18 Pediatric ophthalmology

Retinopathy of prematurity

Retinopathy of prematurity (ROP) was first reported in 1942. By the 1950s it was the leading cause of childhood blindness. At this point, tight oxygen control was introduced, with a dramatic fall in ROP but a significant rise in neonatal death and neurological disability. Supplemental oxygen therapy is now considered a compromise between these conflicting results.

Risk factors

•Low gestational age (≤31 weeks).

•Low birth weight (<1500 g).

•High or variable oxygen tension.

Classification (see Fig. 18.1)

Stages

•Stage 1: demarcation line: flat white line separating vascular from avascular zones.

•Stage 2: ridge: line becomes elevated, thickened, and may become pinkish.

•Stage 3: extraretinal fibrovascular proliferation: vascular tissue grows from the posterior margin onto the retina or into the vitreous.

•Stage 4: subtotal retinal detachment: extrafoveal (4A) or foveal (4B).

•Stage 5: total retinal detachment.

•Plus disease: these signs of vascular incompetence include arterial tortuosity and venous dilation (sometimes present: iris vessel dilation, pupil rigidity, and vitreous haze).

Location

•Zone 1: circle centered on the disc, with radius twice the disc–foveal distance.

•Zone 2: ring centered on the disc, extending from zone 1 to ora nasally and equator temporally.

•Zone 3: remaining temporal crescent.

Extent

• Measured in clock-hours.

Threshold disease

Originally an estimate of when progression and regression were equally likely, this is now used as the level at which treatment is indicated. Threshold disease is defined as stage 3 + disease in zones 1 or 2 and of 5 continuous or 8 noncontinuous clock-hours. Threshold ROP as a criterion to treat ROP has been replaced by type 1 vs. type 2 ROP.

Type 1 vs. type 2 ROP

The Early Treatment of ROP (ETROP) Study supported retinal ablative therapy for eyes with type 1 ROP, defined as zone 1, any stage ROP with plus disease; zone 1, stage 3 ROP without plus disease; or zone 2, stage 2 or 3 ROP with plus disease.

Normal vascularization occurring:

zone 2 complete, zone 3 partial

ROP:

ridge with extraretinal fibrovascular proliferation (stage 3 disease) in zone 2

Figure 18.1 ROP zones and classification.

Screening

Screening should be performed on those infants ≤31 weeks of age or <1500 g. This should start 42–49 days postnatally and continue at least every 2 weeks until 1) progression of retinal vascularization into zone 3 without zone 2 ROP, or 2) full vascularization has occurred.

Indirect ophthalmoscopy with a 28D lens permits a wide field of view. Dilate in advance (cyclopentolate 0.5% + phenylephrine 2.5%) and consider a lid speculum and scleral indentation as needed.

Treatment

Treatment is recommended for threshold disease and worse; however, recent evidence suggests that high-risk prethreshold disease may also benefit. Cryotherapy has been used for over 30 years but has largely been replaced by laser photocoagulation, which is more portable, better tolerated, and more effective for posterior disease. Photocoagulation should be nearly confluent (half burn-width separation), should extend from the ora up to the ridge, and should surround the full 360º.

Vitreoretinal surgery aims to repair or prevent progression of ROPassociated retinal detachment (stages 4A, 4B, and 5). Unfortunately, results are generally disappointing.

634 CHAPTER 18 Pediatric ophthalmology

Other retinal disorders

ROP-like syndromes

Familial exudative vitreoretinopathy (FEVR)

This rare condition usually shows autosomal dominant inheritance (Ch11q). Clinical features include abrupt cessation of peripheral retinal vessels at the equator (more marked temporally) and vitreous bands in the periphery.

Complications include fibrovascular proliferation, macular ectopia, retinal detachment (similar to ROP), and subretinal exudation (similar to Coats’ disease).

Incontinentia pigmenti (Bloch–Sulzberger syndrome)

This rare condition shows X-linked dominant inheritance being lethal in utero for male embryos. Clinical features include abnormal peripheral vasculature, gliosis, tractional retinal detachment, and systemic features such as abnormal teeth, cutaneous pigment whorls, and CNS anomalies.

Retinal dysplasia

A number of conditions are associated with more extensive retinal abnormalities, probably arising from abnormal development involving the inner wall of the optic cup. Clinical features include extensive retinal folds, retinal detachments, retinal hemorrhages, vitreous hemorrhages, retrolental gray mass, and phthisis bulbi.

Associated syndromes include Patau’s syndrome (p. 638), Edward syndrome (p. 638), Norrie disease (retinal dysplasia, deafness, dIQ), and Walker–Warburg syndrome (retinal dysplasia, muscular dystrophy, Dandy–Walker malformation).

Other retinochoroidal disorders

Many stationary and progressive disorders of photoreceptors, RPE, choroid and retinal vasculature present in childhood. They are discussed elsewhere in this book: retinitis pigmentosa (p. 456), congenital stationary night blindness (p. 458), macular dystrophies (p. 459), choroidal dystrophies (p. 462), hereditary vitreoretinal degenerations (p. 389), albinism (p. 464), and Coats’ disease (p. 452).

DEVELOPMENTAL ABNORMALITIES 635

Developmental abnormalities

Anterior segment

Anterior segment dysgenesis results in a variety of abnormalities of variable severity (Box 18.1). The Axenfeld–Rieger spectrum tends to have autosomal dominant inheritance whereas Peters’ anomaly is usually sporadic. All are associated with glaucoma.

Rieger’s anomaly may be associated with systemic abnormalities (teeth small and fewer than normal, maxillary hypoplasia), when it is known as Rieger syndrome. More recently, all disorders falling into this spectrum have been grouped as Axenfeld–Rieger syndrome.

Box 18.1 Anterior segment dysgenesis

Optic fissure

A coloboma is a defect resulting from failure of closure of an embryological fissure. Within the eye, defects may occur anywhere from the optic disc to iris, and vary dramatically in size and severity. Colobomas may be blinding and may be associated with more extensive disease.

Vitreous

Abnormalities within the vitreous cavity include remnants of the hyaloid vascular system (Table 18.28), and abnormalities of the vitreous structure, (e.g., type II collagen abnormalities resulting in Stickler syndrome).

Table 18.28 Hyaloid remnants