Management Of Binocularity When Keratoconus Affects Unitaleral Vision

Keratoconus is a condition in which the cornea thins and gradually bulges outward into a cone shape. This causes blurred and distorted vision. In the early stages, vision problems may be corrected with glasses or soft contact lenses. However, in advanced stages, patients often require specialized hard contact lenses to maintain proper focus. When keratoconus developes asymmetrically between the eyes, significant differences in visual acuity (VA) can impair binocular vision. The purpose of this study is to fit Scelar lenses (SL) when keratoconus affects unilateral vision aiming to enhance vision at the earliest possible stage and preserve binocularity.

Centro Oftalmológico Integral – MIRANZA COI Bilbao. Rodríguez Arias 6º, Bilbao (Basque Country), Spain.

A 22-year-old male patient with bilateral keratoconus. He presented with spontaneous VA of -0.5 logMAR in the right eye (OD) and 0.0 logMAR in the left eye (OS). In OD, we found a manifest refraction of +0.50 (-4.50) x 130º, VA -0.20 logMAR. Scleral lenses were chosen for treatment. Scleral lenses are made from rigid gas-permeable materials. They are large-diameter contact lenses that rest on the sclera, cover the entire cornea and provide a more stable fit. They are lenses that are custom-fit to each patient’s eye shape and size, which helps to ensure maximum comfort and provide excellent optics. A OneFit Med was fitted, with a central sagittal depth of 240 microns between the lens and the cornea, achieving a final VA of -0.05 logMAR.

To reach the final fitting, we had to use two lenses. The final lens provided full-day comfort, maintaining a VA above -0.10 logMAR. It allows the patient experiences a VA 0.0 logMAR and a stereopsis with the Timus test of 791‘’. After three months of continuous use, the patient’s VA and comfort levels remained comparable to the left eye (VA 0.0 logMAR). No ocular surface alterations were observed, and topographic stability in the treatment area was maintained. The patient experiences great improvement in binocularity, and the values of stereopsis with the Timus test is 148’’.

As demonstrated in this case report, scleral lenses can effectively maximize visual acuity without the need for surgery. The vision achieved with these lenses is significantly improved due to reduced optical aberrations. After three months of use, the patient experienced an improvement in their binocular funtion, achiveing normal stereopsis values.