PURPOSE. Purpose: To assess the effects of long-term contact lens wear on corneal thickness and observe differences based on rigid versus soft lens material.
METHOD. Methods: This analysis included Scanning Slit Topography ( Orbscan data) on 124 consecutive patients, 248 eyes, who were seen for refractive surgery evaluations for one surgeon. Minimum pachymetry, history of contact lens wear with type of material was gathered on all subjects. All soft contact lenses wearers had removed their contact lenses for at least 2 weeks prior to exam, and rigid lens wearers removed their contact for at least three weeks prior to exam. Association between corneal thickness and type of contact lens was tested using a linear mixed model that adjusted for correlation between right and left eyes in the same patient. Least squares means were computed for each contact lens type and compared using Scheffe’s method to adjust for multiple comparisons and for imbalances in allocation of individual eyes with different inherent corneal thicknesses to type of contact lens.
RESULTS. Results: There were 62 patients (124 eyes) who had not worn contact lenses with least squares mean pachymetry of 546.4 microns +- 3.5 standard error (SE). 39 patients (78 eyes) had worn soft contact lenses with least squares mean pachymetry of 543.2 microns +- 3.8 SE. 23 patients (46 eyes) had worn rigid contact lenses with least squares mean pachymetry of 509.4 microns +-6.9 SE. Mean pachymetry differed significantly between eyes wearing rigid lens versus no lens (p<0.0001), and between eyes wearing rigid lens versus soft lens (p=0.0002). There was no significant difference between eyes wearing no lens vs. soft lens (p=0.65).
CONCLUSIONS. Conclusion: Long term rigid contact lens wear appears to decrease the corneal thickness in this group of healthy eyes compared to no contact lens wear. Long term soft contact lens wear did not appear to change corneal thickness compared to no contact lens wear.