Possibilities of increasing contact lens tolerance in keratoconus (a clinical case study)

Abstract

Optical correction of keratoconus (KC) is intended to simultaneously solve two tasks: elimination of myopic defocus and irregular astigmatism. In terms of the latter, hard contact lenses (HCL) should be considered as the first-choice method for optical correction of KC. HCL are currently the most effective means of optical correction of refractive errors induced by KC. Despite this, it should be noted that adherence of patients to this method of correction does not always correspond to results. Most often, limitations of HCL use in KC are associated with the so-called intolerance of correction. The term «correction intolerance» should be considered as a general complex of potential subjective symptoms and clinical manifestations that limit the possibility of using a particular method of optical correction. In this clinical observation, subjective discomfort when wearing lenses was practically eliminated by changing the design of the lens and switching from corneal to scleral HCL. The second problem was caused by clinical manifestations of corneal hypoxia (growth of newly formed vessels in the limbal region of the cornea) and attempts to solve it were associated with improved tear production and increased oxygen permeability of the material HCL are made of. The observed stabilization of the growth of newly formed vessels should be considered as a positive (although in need of dynamic evaluation) result of these therapeutic measures.