To observe the progression of keratoconus over 3 years using Orbscan II, and to estimate risk correlations with rapid progressive changes.METHODS
Fifty-six eyes of 35 patients (mean age: 25.9±5.7 years, range: 18 to 35 years) with keratoconus were reviewed whose sex, age, visual acuity, refractive error, atopy, eye rubbing habits, family history of keratoconus, hard contact lens wear, intraocular pressure, keratometric reading, corneal shape, corneal thickness index, and corneal asphericity had been determined. The keratometric change over 3 years was evaluated using Orbscan II, with 6-month intervals between each examination. All patients selected had less than moderate keratoconus on initial examination.RESULTS
The rate of keratometric change was 0.78±0.99 diopters (D)/half-year. In 30 eyes, the apparent progression was evident with a rate of keratometric change of 1.37±1.08 D/half-year, whereas the rate of change was 0.15±0.15 D/half-year in eyes exhibiting no apparent progression (P=.001). Logistic regression analysis showed that eye rubbing (odds ratio [OR] = 3.810; 95% confidence interval [CI] = 1.194–12.158) and inferior steepening compared to superior steepening (OR = 5.465; 95% CI = 1.667–17.857) were associated with progression after diagnosis (P<.05).CONCLUSIONS
Careful attention must be paid to the presence of eye rubbing and corneal shape with inferior steepening at the time of diagnosis, as these factors may help in predicting the rapid progressive change in keratoconus.