Interactive Case Reports

Corneal cross-linking for keratoglobus using individualized fluence

Case Report Details

First Author: F.Hafezi SWITZERLAND

Co Author(s):    E. Torres-Netto   S. Kling   R. Abrishamchi   H. Abdshahzadeh   F. Gilardoni   N. Hafezi     

Abstract Details

Purpose:

Currently, corneal ectasias presenting with a stromal thickness of less than 400 µm have limited options to stabilize progression of the disease. CXL techniques such as stromal swelling with hypo-osmolaric riboflavin or application of a contact lens allow for treatment of corneas with a minimal thickness of 300 µm with variable outcomes and reduced efficacy. We recently published a new algorithm that individually adapts total irradiation (fluence) to the individual patient’s stromal thickness. Here, we present a case of progressive keratoglobus in an ultra-thin cornea of 211 µm stromal thickness that was successfully arrested with CXL using individualized fluence.

Setting:

The study was conducted at the ELZA Institute AG, Dietikon/Zurich, Switzerland.

Report of Case:

A 36-year-old male presented in November 2016. Keratoglobus had been diagnosed when he was 16 years old. He had no history of allergic disease or eye rubbing but showed a marfanoid habitus, hypermobile joints and scoliosis. Ophthalmological examination of the left eye showed an apical scar, substantial stromal thinning over the entire cornea, Vogt striae in the paracentral deep stroma and a CDVA of 20/400. Ectasia was established using anterior segment OCT and Scheimpflug imaging. Minimal corneal thickness was 244µm and maximal keratometry (Kmax) readings reached 81.9D. The patient also reported a continuous deterioration: in 2010, placido-based topography showed Kmax readings of 65.8D and in 2011, CDVA of the left eye was 20/50. CXL was performed in December 2016. After local anesthesia, a speculum was inserted, and the epithelium was removed over 10 mm using a hockey knife. 0.1% hypo-osmolaric riboflavin without dextrane or HPMC was instilled every 2 minutes for 20 minutes. Stromal thickness was measured every 5 minutes using ultrasound pachymetry and was 244 µm prior to and 211 µm after the manual abrasio. Immediately prior to irradiation, minimal stromal thickness was 231 µm. The cornea was irradiated with UV-A light using 3 mW/cm2 and our published algorithm at an irradiation diameter of 10 mm. Full re-epithelialization occurred at day 8 after CXL. The remainder of the post-operative period was uneventful. Twelve months after CXL, CDVA with glasses was 20/200, Kmax was 80.6D, and pachymetry at the thinnest point was 243 µm. The cornea showed no signs of endothelial decompensation at the slit lamp, while endothelial specular microscopy was not possible technically. At the last visit at 32 months after CXL, the patient presented with stable refraction and similar Kmax readings. Following adaptation of scleral lenses, visual acuity was 20/20 with contact lenses.

Conclusion/Take Home Message:

CXL using individualized fluence allows for the treatment of keratoglobus with a minimal stromal thickness of 211 µm. To our knowledge, this is the first time that CXL was applied in keratoglobus and corneal cross-linking using individualized fluence might represent a novel therapeutic approach for the management of keratoglobus.

Financial Disclosure:

None