Purpose: To estimate the time taken for topometric indices to stabilize in keratoconic corneas following cessation of habitual RGP contact lens wear.
Methods: A total of 29 eyes of 20 patients, diagnosed with mild to severe keratoconus were included in this prospective observational study. All patients were experienced RGP contact lens wearers (either conventional RGP or Rose K2 lens) with each patient having used these lenses for at least a year. Corneal topography was performed immediately following discontinuation of habitual contact lens wear at baseline and each of four consecutive visits, 1-week apart.
Results: An overall reduction in the keratometry and thickness values were noted on tomography immediately following cessation of contact lens wear and these indices increased significantly in the 1st week (P < 0.001). Consecutive visits following the first visit did not show any significant change in the topometric parameters (P > 0.05). Subgroup analysis revealed a similar trend in eyes with "severe" keratoconus and in eyes fitted with the "three-point touch" philosophy. However, eyes with "mild-moderate" keratoconus and those fitted with "apical clearance" fitting philosophy showed marginal differences even within the 1-week period of lens cessation.
Conclusion: Maximum changes in keratometry and pachymetry values following discontinuation of RGP lens wear stabilize within the 1st week of cessation of rigid lens wear in a keratoconic cornea. These changes were more pronounced in patients with severe keratoconus and those with an apical bearing fit. This information would be useful for practitioners to assess the progression of keratoconus in RGP lens users before collagen cross-linking.
Keywords: Apical clearance; contact lens; keratoconus; three-point touch; topography.