Cornea Cases

Title:

A case of intrastromal corneal ring segments implantation in a patient with the PAX6 gene mutation

Case Report Details

First Author: M.Gerasimov RUSSIA

Co Author(s):    B. Malyugin   S. Borzenok   A. Marakhonov   V. Kadyshev   R. Zinchenko        

Abstract Details

Purpose:

To describe a patient's clinical manifestation and clinical course with primary limbal stem cells deficiency following intrastromal corneal ring segments (ICRSs) implantation.

Setting:

The S. Fyodorov Eye Microsurgery Federal State Institution, Moscow Research Center for Medical Genetics, Moscow

Report of case or case series:

A 34-year-old woman was presented in the clinic with visible cornea OS changes, permanent redness, and low vision for both eyes. Her ocular history included ICRSs implantation OS two years ahead and an episode of keratitis on the same eye 1.5 years back. BCVA was for OD = 0.3, OS = 0,1. Spherical equivalent (SE) for OD was -7.25. SE for OS was not countable. IOP by pneumotonometry was 19.1 OD mm Hg and 15.9 mm Hg OS. Slit-lamp examination showed subepithelial haze and irregular corneal epithelium, superficial neovascularization, absence of palisades of Vogt, and corectopia OU. Two 180 degree's ICRSs were located in the stroma OS with a nasal shift. Deep corneal neovascularization and stromal scarring along the upper segment and calcification and stromal scarring along the lower segment were noted in OS. Fluorescein staining demonstrated an absence of epithelial defects for OS, but bilateral late corneal epithelium staining was noted. Mean corneal endothelial cell density (μ±σ, cells/mm2) was 3133±105 OD, 2871±107 OS. Optical coherent tomography findings were as follows. Minimal central corneal thickness was 506 µm OD and 458 µm OS; central corneal epithelium thickness (min-max) was 14-55 µm OD and 8-64 µm OS. Minimal stromal thicknesses behind upper and lower segments were 80 µm and 38 µm, respectively. Iris and foveal hypoplasia were unexpectedly noticed in both eyes. A detailed dialogue uncovered the fact that her younger daughter developed congenital aniridia. Genetic tests confirmed a missense mutation in exon 5 of the PAX6 gene for both. A rare c.19G>C/+ genotype was identified as the most likely cause of congenital aniridia in a family. Topical medications were used for treatment because the patient was not agreed to remove the ICRSs.

Conclusions/Take Home Message:

The role of a missense mutation of the PAX6 gene in ocular surface pathology and other ocular abnormalities needs to be defined. Patients with an unusual presentation of the corneal limbus and abnormal iris anatomy noted during the routine ophthalmic examination should be evaluated more accurately. Intrastromal corneal ring segment implantation is not recommended for patients with primary limbal stem cells deficiency.