Congenital ectopia lentis and secondary buphthalmos likely occurring as an autosomal recessive trait

Ectopia lentis associated with primary congenital glaucoma

PURPOSE

To describe 3 cases of ectopia lentis (EL) associated with primary congenital glaucoma (PCG) and differentiate between primary and secondary EL regarding pathogenesis.

METHODS

We reviewed the clinical charts of 3 children previously diagnosed with congenital glaucoma who developed secondary EL. The following points were noted: medical and surgical history, refraction, keratometry, corneal diameter, axial length (AL), intraocular pressure, and cup/disc ratio.

RESULTS

The 3 patients were respectively aged 12, 3, and 4 months. A trabeculectomy was performed in both eyes at 1-week interval in all cases. The EL was noted during follow-up controls. Lensectomy/vitrectomy was performed in 2 patients, in case of high astigmatism (>5.00 D) and/or the lens border visible in the pupillary area. Postoperative refraction was hyperopic.

CONCLUSIONS

Ectopia lentis secondary to PCG should be differentiated from primary EL regarding pathogenesis. Anterior segment distension appears to be the principal mechanism in these cases. Postoperative hyperopia is observed despite the increased AL secondary to PCG. These biometric results are due to global distension of the globe, which also flattens the cornea with consequently lower refractive effect.

A homozygous mutation in ADAMTSL4 causes autosomal-recessive isolated ectopia lentis

Ectopia lentis is a genetically heterogeneous condition that is characterized by the subluxation of the lens resulting from the disruption of the zonular fibers. Patients with ectopia lentis commonly present with a marked loss in visual acuity in addition to a number of possibly accompanying ocular complications including cataract, myopia, and retinal detachment. We here describe an isolated form of ectopia lentis in a large inbred family that shows autosomal-recessive inheritance. We map the ectopia lentis locus in this family to the pericentromeric region on chromosome 1 (1p13.2-q21.1). The linkage region contains well more than 60 genes. Mutation screening of four candidate genes revealed a homozygous nonsense mutation in exon 11 of ADAMTSL4 (p.Y595X; c.1785T-->G) in all affected individuals that is absent in 380 control chromosomes. The mutation would result in a truncated protein of half the original length, if the mRNA escapes nonsense-mediated decay. We conclude that mutations in ADAMTSL4 are responsible for autosomal-recessive simple ectopia lentis and that ADAMTS-like4 plays a role in the development and/or integrity of the zonular fibers.

Anterior axial lens subluxation, progressive myopia, and angle-closure glaucoma: recognition and treatment of atypical presentation of ectopia lentis

PURPOSE

To describe the clinical features of an atypical presentation of ectopia lentis consisting of primary anterior axial lens subluxation in childhood, associated progressive myopia, and complicating angle-closure glaucoma; to facilitate early diagnosis of this triad; and to report the results of lensectomy for treatment.

METHODS

A retrospective case review of eight patients. Clinical course, visual acuity, gonioscopy, axial length, refraction, fundus examination, associated systemic features, and results of treatment are provided.

RESULTS

This subgroup of patients with ectopia lentis is at risk for progressive, synechial, angle-closure glaucoma. Identification of a clinical triad consisting of rapidly increasing myopia, normal axial length, and progressive axial subluxation leads to earlier diagnosis. Prophylactic lensectomy provides a safe and sight-saving treatment that arrests and, at times, reverses the progression of angle-closure glaucoma.

CONCLUSIONS

Ectopia lentis with anterior axial subluxation and progressive myopia can be a sight-threatening condition when significant forward mobilization of the lens results in synechial angle-closure glaucoma. Recognition of this clinical entity can expedite diagnosis and prevent irreversible loss of vision secondary to glaucoma. Because the primary mechanism of angle closure is angle crowding, peripheral iridotomy does little to control the rise in intraocular pressure. Prophylactic lensectomy has proven to be the most reliable treatment in our experience.

Bilateral megalocornea with unilateral lens subluxation

Megalocornea refers to an enlarged cornea that measures 13 mm or more in horizontal diameter in the absence of raised intraocular pressure. We describe a five-month-old boy with bilateral megalocornea with unilateral lens subluxation. No other ophthalmological abnormality was present. In all previously reported cases with megalocornea and ectopia lentis, the lens was cataractous and the dislocation was in the inferior and posterior direction. In contrast, our case had a clear lens which was displaced superonasally.