Purpose: To compare the central corneal thickness (CCT) values of long-term wearers of different types of contact lenses with those of each other and a normal control group.
Methods: Twenty-three healthy eyes with no history of contact lens wear were used for the control group. Forty-eight eyes were evaluated in four different groups according to the type of contact lens worn; each group comprised 12 eyes. Group 1 (SofLens 38) and group 2 (Contact Day 30) had worn daily-wear frequent-replacement soft contact lenses with a 38% and 55% water content, respectively, and they had worn their lenses for an average of 4.28 +/- 1.70 years and 3.71 +/- 1.11 years, respectively. Group 3 (Wöhlk A90) and group 4 (Conflex-air) had worn daily-wear rigid gas-permeable (RGP) contact lenses with a Dk/t value of 68 and 22, respectively, and they had worn their lenses for an average of 3.00 +/- 0.63 years and 3.25 +/- 1.17 years, respectively. CCT values in micrometers were measured by optical coherence tomography.
Results: When comparing the CCT between the control group and the contact lens groups, the CCT was significantly thinner in the group wearing Conflex-air RGP contact lenses with a low Dk/t value (P = 0.010). In comparing the CCT among the four contact lens groups, the CCT was significantly thinner in the group wearing SofLens 38 contact lenses with a water content of 38% than in the group wearing Contact Day 30 contact lenses with a water content of 55% (P = 0.004). There was also significant thinning in the group wearing Conflex-air RGP contact lenses versus the group wearing Contact Day 30 soft contact lenses (P = 0.0005).
Conclusions: CCT was significantly thinner in patients wearing long-term low-Dk/t RGP contact lenses compared to no contact lens wear and soft contact lenses with a water content of 55%. CCT was also decreased significantly in long-term soft contact lens wear with a water content of 38% compared to 55%.