Ocular surface anatomy and physiology underlying scleral lens application

Abstract

AbstractContact lenses (CL) are in the public interest mainly for cosmetic reasons. Because of supposed simplicity of fitting, adaption, care and safety, soft CL are the predominant type world‐wide. Only few rigid gas permeable (RGB) CL are applied even though it may appear that they have less side effects. Another type of CL rests on the sclera and is hence termed scleral lenses. In contrast to the aforementioned CL, that cover only the cornea (RGB) or extend just beyond, scleral lenses have a wide diameter and cover also a large part of the bulbar conjunctiva. This leads to different impact on the anatomy, physiology and pathology of the ocular surface. Below their apex is a deep tear pond that allows to cover even major deformations of the cornea as occur in keratokonus, recurrent surface defects or scars without touching them. New sophisticated diagnostic techniques e.g. for measuring ocular surface topography as well as advanced designs and materials of standard or custom made lenses have significantly improved the fitting and the wearing comfort of scleral lenses. Therefore, scleral lenses have emerged in recent years as a new and EVER more exciting medical tool for the dedicated ocular surface specialist.