Specular Microscopy Over a Hydrogel Contact Lens

To the Editor.  —In vivo measurements of human corneal endothelial cell density can be made with the specular microscope. These measurements provide clinically useful information in evaluating the effects of corneal disease processes, intraocular lens implantation, cataract surgery, and contact lens wear on the morphology of the endothelium.The technique used presently to measure corneal endothelium requires applanation of the microscope objective. While specular microscopy is desirable for evaluation of a wide assortment of corneal diseases, direct applanation of the objective may be contraindicated in patients with irregular corneal epithelium and/or epithelial dystrophy, or in patients wearing therapeutic or continuous-wear hydrogel lenses that need not or should not be removed.We have found that it is possible to do specular microscopy directly over a hydrogel contact lens and obtain good-quality photographs of the endothelium. The photographs are equivalent to those obtained using direct applanation. Use of the contact lens between