Posters

Congenital cataract surgery and SOX2 gene evaluation in microphthalmic eyes

Poster Details

First Author: D.Borroni LATVIA

Co Author(s):    M. Ferronato   E. Elksnis   E. Sture   I. Orube   Z. Krumina   K. Bajracharya

Abstract Details

Purpose:

In children congenital cataracts rappresent 25% to 30% of avoidable blindness and Microphthalmus has been found in 7% to 17% of these patients. Our purpose is to report the outcomes and complications of congenital cataract sugery with Intraocular-Lens(IOL) implantation in Microphthalmic eyes. The aims of the surgery are to decrease amblyopia, strabisums and give a full visual development to visual system. In Microphthalmic eyes IOL implantation is more challenging due to small anatomy but it gives better visual prognosis than eyes left aphakic. SOX2 has been identified as a major causative gene of Microphthalmus. A screening of SOX2 was performed.

Setting:

Riga Stradins University – Latvija

Methods:

The study involved 20 Microphthalmic eyes from 14 children younger than 3 years of age with congenital cataract. Surgeries consisted in aspiration of the lens and IOL implantation. Eyes with inflammation, ocular trauma, aniridia, chorioretinal coloboma or vitreo-retinal diseases were excluded. 6 patients had bilateral cataract. The outcome measures were Intraocular Pressure (IOP), Best-Corrected Visual Acuity (BCVA), intraoperative and postoperative complications. Genomic DNA was extracted from blood. SOX2 coding region was amplified and PCR product were sequenced with Big Dye Terminator v3.1 (Applied Biosystems, Foster City, CA). Initially identified changes were confirmed by additional independent PCR and sequencing experiments.

Results:

Mean age at the time of surgery was 23.9 ± 1.7 months. Mean ocular axial length was 18.6 ± 0.7 mm. Mean preoperative IOP was 9.3 ± 1.2 mmHg and 10.8 ± 2.7 mmHg on final follow­up. No one intraoperative complications happened. Postoperative complication hapened in one eye (the shortest one with 17.9mm of axial lenght) who developed secondary visual axis opacification. Preoperative and postoperative BCVA was 2.01 ± 0.89 logMAR and 0.31 ± 0.06 logMAR in bilateral cases and 1.81 ± 0.97 logMAR and 0.32 ± 0.13 logMAR in unilateral cases, respectively. SOX2 mutations appear in 3/14 cases (15%).

Conclusions:

In microphthalmic eyes primary IOL implantation in congenital cataract surgery resulted in a significant BCVA improvement with minimal postoperative and no intraoperative complications. Glaucoma and axial opacifications are well knowed long term postoperative complications and children who underwent congenital cataract surgery must be followed-up regularly. Shorter axial lenght is a significat risk factor for post-operative complicatons. SOX2 mutation is found to be one of the major causes of Microphthalmus and further studies of mutations affecting the lens membranes (aquaporins/Mip, Lim-2 or connexins) or the structural proteins of the cytosol will give a better uderstanding of congenital cataracts in developing eyes. FINANCIAL DISCLOUSRE: NONE