Ординатура / Офтальмология / Английские материалы / Pediatric Ophthalmology for Primary Care 3rd edition_Wright, Farzavandi_2008

Figure 22 3.

Lamellar cataract with the opacity (identified in red) occurring in the cortex just peripheral to the lens nucleus.

recessive, and autosomal dominant. There is no specific treatment, and man agement is directed to delaying renal failure.

Posterior Cataracts

Posterior Lenticonus

Posterior lenticonus is a congenital thinning and posterior bowing of the posterior capsule (Figure 22 5). Early in infancy, the cortex is relatively clear. Over time, however, the area of cortex surrounding the abnormal posterior capsule opacifies and the cataract progresses. The visual prognosis for posterior lenticonus is relatively good because the visual axis is fairly clear during the early visual developmental period and the opacity pro gresses later.

Persistent Hyperplastic Primary Vitreous

Persistent hyperplastic primary vitreous (PHPV) represents abnormal regression of the primitive hyaloid vascular system. This produces a fibro vascular tissue that emanates from the optic disc as a stalk and then courses to the back of the lens where it forms a retrolental membrane (Figure 22 6A). This membrane may extend to the ciliary processes.

Figure 22 4.

Anterior polar cataract. A, Drawing of a pyramidal anterior polar cataract with anterior conical opacity consisting of fibrous tissue. B, Companion photograph showing white conical area of fibrosis coming off the anterior capsule, through the pupil, and protruding into the anterior chamber. Over time, progressive cortical changes occurred and this patient required cataract surgery. At the time of surgery, the fibrotic conical opacity was difficult to fragment and required removal with intraocular forceps.

Figure 22 5.

Posterior lenticonus is a posterior bowing of the posterior capsule with capsular thinning. This capsular ectasia produces a progressive posterior capsular opacity. A, Diagram of posterior lenticonus with the posterior ectasia. B, Slitlamp photograph of posterior lenticonus. The circular opacity represents the area of thinning and posterior bowing

of the posterior capsule.

A

Figure 22 6.

Persistent hyperplastic primary vitreous (PHPV). A, Diagram of PHPV showing a fibrovascular stalk, which emanates from the optic nerve and extends to the posterior capsule of the lens to form a retrolental fibrovascular membrane. In severe forms of PHPV, the fibrovascular membrane contracts with time, pulling the ciliary body centrally, shallowing the anterior chamber, thus causing angle closure glaucoma. B, Clinical photograph of severe PHPV with the fibrovascular membrane pulling the ciliary processes centrally. The dark black tissue with the scalloped border is the ciliary body being pulled to the center of the pupil by the fibrovascular membrane. The pink appearance of the membrane is secondary to vascularization of the membrane.

Over time, the fibrovascular membrane can contract, pulling the ciliary pro cesses centrally (Figure 22 6B). Surgery is indicated to improve vision and prevent amblyopia, but also to save the eye. If left untreated, severe forms of PHPV can lead to shallowing of the anterior chamber, angle closure glau coma, and eventual loss of the eye in late childhood. Overall, the surgical prognosis with PHPV is relatively good as long as the retina is normal.

Posterior Subcapsular Cataracts

Posterior subcapsular cataracts involve the posterior lens cortex and are associated with Down syndrome, chronic steroid use, and blunt trauma. They also may be idiopathic.

Oil Drop Cataract

Oil drop cataract is the term typically given to a faint opacity in the cen tral aspect of the posterior cortex that is seen on retro illumination and is associated with galactosemia. Treatment of galactosemia is through dietary restriction. Treatment can result in reversal of the cataract if the galacto semia is diagnosed early and the dietary restriction is instituted prior to lenticular cortical scarring.

Christmas Tree Cataracts

Christmas tree cataracts consist of multiple small flecks of various colors that reflect light and give the appearance of a lighted Christmas tree. These cataracts can be associated with myotonic dystrophy, pseudohypoparathy roidism, and hypoparathyroidism.

Etiology of Infantile Cataracts

The etiologies of unilateral versus bilateral congenital cataracts are listed in Table 22 2, and systemic diseases associated with cataracts are listed in Table 22 3. The most common identifiable cause for bilateral cataracts is genetic with autosomal dominant inheritance; however, recessive and X linked patterns have also been described.

Unilateral Cataracts

Unilateral infantile cataracts are rarely caused by a systemic disease, except in some cases of intrauterine infections such as rubella. Approximately 20% to 30% of rubella cataracts are unilateral. Thus, the presence of a unilateral cataract does not totally rule out the possibility of an associated systemic

Table 22-2. Etiology of Congenital Cataracts

Unilateral Cataracts

1.Idiopathic (40%)

2.Posterior lenticonus (20%)

3.Persistent hyperplastic primary vitreous (PHPV) (10%)

4.Anterior polar (10%)

5.Other (9%)

a.Anterior segment dysgenesis

b.Posterior pole tumors (rare)

6.Traumatic (10%)—consider child abuse

7.Intrauterine infection (rubella) (1%)

Note: Asymmetric bilateral lens opacities may be misinterpreted as a unilateral cataract.

Bilateral Cataracts

1.Idiopathic (50%)

2.Hereditary cataracts (40%) without systemic disease

a.Autosomal dominant (most common)

b.Autosomal recessive

c.X-linked

3.Systemic diseases (5%)

a.Hallermann-Streiff syndrome (midfacial hypoplasia, dwarfism)

b.Lowe syndrome (oculocerebrorenal syndrome)

c.Smith-Lemli-Optiz syndrome

d.Galactosemia

e Hypoglycemia

f.Trisomy

1)Down syndrome (21)

2)Edward syndrome (28)

3)Patau syndrome (13)

g.Alport syndrome

h.Myotonic dystrophy

i.Fabry disease (ceramide trihexosidase deficiency)

j.Hypoparathyroidism

k.Marfan syndrome

l.Pseudohypoparathyroidism

m.Conradi syndrome

n.Diabetes mellitus

o.Peroxisomal biogenesis disorder

p.Wilson disease

4.Intrauterine infection (3%)

a.Rubella

b.Cytomegalovirus

c.Varicella

d.Syphilis

e.Toxoplasmosis

f.Herpes simplex

5.Ocular abnormalities (2%)

a.Aniridia

b.Anterior segment dysgenesis

294 Pediatric Ophthalmology for Primary Care

Table 22-3. Systemic Syndromes and Diseases Associated

With Cataracts

A. Cataracts Associated With Skeletal Disease

Table 22-4. Systemic Evaluation of Pediatric Cataracts

I.HISTORY

A.Family history is critical.

B.Age of onset of cataract.

C.Developmental milestones.

D.Trauma (battered-child syndrome?). II. PEDIATRIC PHYSICAL EXAMINATION

Also consult geneticist or dysmorphologist. III. OCULAR PHYSICAL EXAMINATION

Diagnose specific morphological features of the cataract (ie, PHPV, posterior lenticonus, anterior polar cataract).

IV. REQUIRED LABORATORY TESTS

A.Unilateral cataracts

1.TORCH titer and VDRL

B.Bilateral cataracts

1.ROUTINE

a.TORCH titer and VDRL

b.Urine for reducing substance (after milk feeding)

2.OPTIONAL

a.Red cell galactokinase (developmental cataracts)

b.Serum for amino acids (developmental delay and glaucoma)

c.Calcium and phosphorus (cataracts and metabolic disorders

Approximately 5% to 10% of bilateral cataracts are associated with a sys temic disorder. The workup for bilateral congenital or infantile cataracts should include a careful pediatric examination, a urine test for reducing substance (sugar) after a milk feeding, and TORCH titer (Table 22 4).

Laboratory workup is not necessary if the cataracts can be positively defined as hereditary without other systemic abnormalities.

Cataracts and Infantile Glaucoma

The differential diagnosis of congenital cataracts with glaucoma includes Lowe syndrome, congenital rubella syndrome, anterior segment dysgenesis syndromes, and aniridia with cataract.

Lowe Syndrome (oculocerebrorenal syndrome)

This is an X linked disorder that presents with bilateral congenital cataracts and often with bilateral congenital glaucoma. Infants show severe develop mental delay, hypotonia, and renal failure with aminoaciduria. The progno sis is poor because there is progressive neurologic and renal deterioration with death occurring in late childhood. A dilated slitlamp examination of

the patient’s mother shows multiple punctate white snowflake opacities of the lens (check the lens periphery).

Congenital Rubella Syndrome

Systemic findings of congenital rubella syndrome include congenital heart defects, hearing loss, and mental retardation. Ocular findings include cata racts (15%), salt and pepper retinopathy (25%), strabismus (20%), microph thalmos (15%), optic atrophy (10%), corneal haze (10%), glaucoma (10%), and phthisis bulbi (2%). The retinopathy is stable and usually does not affect vision. Rubella cataracts are caused by invasion of the lens by the rubella virus and are bilateral in 80% of all cases. These cataracts may present with a hazy cornea caused by congenital glaucoma or keratitis. Treatment of the cataract involves removing all of the lens cortex because the patient’s ten dency to postoperative inflammation is increased if residual cortex is left after surgery.

Treatment of Pediatric Cataracts

The strategy for treating congenital cataracts is to provide a clear retinal image as soon as possible to avoid irreversible amblyopia. The most common cause for poor vision after pediatric cataract surgery is amblyopia, which can be unilateral or bilateral. Because of this, a unilateral or bilateral congenital cataract that is visually significant must be visually rehabilitated as soon as possible, even during the first week of life. Treatment is urgent—bilateral congenital cataracts that obscure the visual axis will often result in sensory nystagmus and a bilateral poor visual outcome if not treated by 2 months of age. Most authorities agree that best treatment is very early surgery during the first week of life (Wright et al).

Surgical Technique

Pediatric cataracts and cataracts in young adults (younger than 30 years) can be removed by microinstrumentation using suction and suction cutting modalities. Complications of cataract surgery are unusual, but late com plications include retinal detachment (rare), immediate or late glaucoma (5%), retinal hemorrhages, secondary cortex growth (Elschnig pearls), and endophthalmitis.