Comparison of Hybrid Contact Lenses and Rigid Gas-Permeable Contact Lenses in Moderate and Advanced Keratoconus

Objectives:We aimed to compare the clinical results and topographic data of the new generation hybrid contact lens (HCL) and rigid gaspermeable contact lens (RGPCL) in patients with moderate and advanced keratoconus.Materials and Methods:In this prospective study, HCL users comprised group 1 and RGPCL users comprised group 2. Snellen uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and lens-corrected visual acuity (LCVA); manifest spherical-cylindrical values; corneal topography measurements (flat keratometry [K1], vertical keratometry [K2], mean K, maximum K [Kmax], central corneal thickness [CCT], and thinnest corneal thickness [TCT]); and cone location were recorded.Results:The study included 83 eyes of 51 patients in group 1 and 61 eyes of 40 patients in group 2. The groups were similar in age and gender (p>0.05). Mean LCVA (logMAR) was significantly lower than BCVA in both groups (p0.05). There was also no significant difference between the two groups in terms of keratoconus stages, mean Kmax, CCT, TCT, or cone location (p>0.05), while mean UCVA (logMAR) and mean K were higher in group 2 (p<0.05). In both groups, the visual gain with lenses was higher in eyes with central cones, and there was significantly greater visual increase in group 2 (p=0.039).Conclusion:In moderate and advanced keratoconus, HCLs improved vision as much as RGPCLs and both lenses were more effective for central cones. Nevertheless, longer term of follow-up and larger numbers of patients are needed for long term follow-up results of HCL

The Long-Term Effects of Silicone Hydrogel Contact Lenses on the Ocular Surface and Tear Function Tests

Objectives: To evaluate the effects of three different silicone hydrogel contact lenses, i.e. Balafilcon A (Pure Vision, Bausch & Lomb), Senofilcon A (Acuvue Oasys, Johnson & Johnson), and Confilcon A (Biofinity, CooperVision), on ocular surface after one, three, and sıx months of wear. Materials and Methods: Silicone hydrogel contact lenses (SHCL) were fitted to 58 patients (Balafilcon A to 40 eyes: Group 1, Senofilcon A to 42 eyes: Group 2, and Confilcon A to 34 eyes: Group 3) who have not used any contact lenses before. All groups were graded according to the Cornea and Contact Lens Research Unit’s grading score, and were performed ocular surface disease index scoring (OSDI), tear break-up time (BUT), and Schirmer 1 test. Results: The mean age was 22.45±5.96, 20.76±3.70, 21.00±3.84 years in Groups 1,2, and 3, respectively (p>0.05). While the increase in papillary hypertrophy as well as palpebral and bulbar hyperemia at 1st month in Group 1 and at 6th month at Group 2 were significant, there were no change in Group 3 with the use of SHCL (p<0.05). The mean OSDI, BUT did not show any difference in and between the groups (p>0.05). In Group 3, the Schirmer test was lower than in Groups 1 and 2, which was statistically significant (p=0.048, p=0.003). Conclusion: Factors like lens material, modulus, the presence of an internal wetting agent, and water content play an important role in the effects of SHCL on the ocular surface. In this study, it is demonstrated that SHCL does not cause clinically significant dry eye. (Turk J Ophthalmol 2014; 44: 201-6