Refractive Keratotomy in Keratoconus Suspects
C. Bradley Bowman, Keith P. Thompson, R. Doyle StultingBackground:
We utilized videokeratography to determine the frequency of keratoconus suspects in a refractive surgery population, and compared the results of refractive keratotomy in these patients to those of patients with normal corneal topography.
Methods:
The records of 67 consecutive patients (120 eyes) undergoing refractive keratotomy were reviewed retrospectively. Quantitative measurements of relative inferior corneal steepening (inferior-superior value, I-S value) were obtained from preoperative videokeratography.
Results:
Three of 120 eyes (3 of 67 patients, 4.5%) were identified as keratoconus suspects based on I-S (inferior-superior) values greater than + 1.74 (range, +1.76 to +2.00), which represented two standard deviations (±0.66) above the mean (+0.42). All three of these eyes achieved postoperative uncorrected visual acuity of 20/30 or better. Of those eyes with normal preoperative topography (I-S value +1.74 or less), 90 of 112 (80%) achieved postoperative uncorrected visual acuity of 20/30 or better, and 105 of 112 (94%) achieved 20/40 or better.
Conclusions:
Although long-term follow up is needed to confirm stability of refractive surgery outcome, it appears that keratoconus suspects can obtain acceptable results with refractive keratotomy. Studies on larger patient populations using videokeratography are needed to better define keratoconus, keratoconus suspects, and normal variants of corneal topography and to determine how eyes with abnormal topography respond to refractive keratotomy. [