Effects of corneal scars and their treatment with rigid contact lenses on quality of vision

Objectives: To study the effects of corneal scars and the treatment of these scars with rigid gas-permeable (RGP) contact lenses on quality of vision including straylight. Visual effects were related to scar characteristics such as size and grade. Methods: Straylight and best-corrected visual acuity were measured in 23 patients with corneal scars during and after RGP contact lens wear. Contralateral eyes were used as controls, and age-normal values in case of bilateral scars. Straylight measurements were performed using the compensation comparison method of the Oculus C-Quant instrument. Results: Scarred eye straylight values were 1.53 log(s) without contact lens and 1.60 log(s) with contact lens (P=0.043). Healthy eyes without contact lens had a mean straylight value of 1.13 log(s), corresponding to agenormal values. Contact lens wear increased straylight in healthy eyes to 1.26 log(s) (P<0.001). Visual acuity improved from 0.66 logarithm of minimal angle of resolution (logMAR) to 0.19 logMAR with contact lens wear in eyes with a corneal scar (P<0.001). Conclusions: Corneal scars can have a strong effect on quality of vision by diminishing visual acuity and increasing straylight. The increase in straylight from corneal scars on its own can lead to a serious visual handicap. Contact lens treatment did not improve straylight, but showed a slight worsening. As the recovery of visual acuity with contact lens wear far exceeded straylight increase, contact lenses remain a clinically useful treatment option in most patients with corneal scars.