A 1-Week-Old Baby With Bilateral Cataracts

Muhammad M. Shamim, BS; Madhuri Chilakapati, MD; Kimberly G. Yen, MD

Disclosures

March 22, 2019

Discussion

Anterior polar cataracts constitute approximately 3% of congenital cataracts.[1] They appear as small opacities on the anterior surface of lens.

There are three subtypes of anterior polar cataracts: polar, subcapsular, and pyramidal. Polar cataracts are round, central cataracts with well-defined borders. They are the most common type of anterior congenital cataracts. Anterior subcapsular cataracts do not have well-defined borders.[4] Pyramidal cataracts, which this patient has, are conical in shape and project from the anterior capsule of the lens into the anterior chamber.[5] Pyramidal cataracts have the highest rate of progressing to being visually significant and have been associated with a greater than 90% risk for amblyopia.[4] Rarely, spontaneous dehiscence of the pyramid into the anterior chamber may occur.[6]

Several genes implicated in anterior polar cataracts have been described in the literature. Among these are mutations in EPH receptor A2 (EPHA2), alpha 8 gap junction protein (GJA8), gamma D crystallin (CRYGD), eyes absent homolog 1 (EYA1), major intrinsic protein of lens fiber (AQP0), heat shock transcription factor 4 (HSF4), beta B1crystallin (CRYBB1), and alpha crystallin (CRYAA) genes. Translocations that have been described include unbalanced 3;18 and balanced reciprocal 2;14. Anterior polar cataracts can also be associated with genetic ocular diseases such as aniridia and Peter's anomaly.[2]

Several theories have been postulated to explain the mechanism of anterior polar cataract formation. One suggests that an intrauterine infection is a trigger, resulting in transformation of the epithelial cells of the lens, whereas another suggests that a persistent vascular tunica adversely affects nutrition to the lens, leading to opacification.[7]

Many congenital anterior polar cataracts tend not to progress with age and typically do not require surgical intervention.[8] However, several studies have shown that approximately one third of patients with anterior polar cataracts develop amblyopia. Jaafar and colleagues[8] reported that 32% of 63 patients with anterior polar cataracts developed amblyopia. In their study of 59 patients, Ceyhan and colleagues[9] reported that 28.8% developed amblyopia. Dixit and colleagues[4] reported that 28.6% of patients with bilateral cataracts and 35.3% of patients with unilateral cataracts developed amblyopia. Wheeler and colleagues[5] demonstrated that patients with the pyramidal subtype of anterior polar cataracts are more likely to develop amblyopia than the other subtypes.

Anisometropia is the main cause of amblyopia in patients with anterior polar cataracts. The reason for development of anisometropia is unclear, but anisometropic astigmatism, myopia, and anisometropia have all been described.

Cataract surgery is infrequently needed for patients with anterior polar cataracts, but the pyramidal subtype conveys an increased risk and should be monitored more closely for potential progression that requires surgery. Patients with anterior polar cataracts should be followed closely for development of refractive errors that can lead to amblyopia.[4]

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