Tear Film Surface Quality With Rigid and Soft Contact Lenses
The aim of this study was to measure tear film surface quality (TFSQ) using dynamic high-speed videokeratoscopy during short-term (8 hrs) use of rigid and soft contact lenses.A group of 14 subjects wore 3 different types of contact lenses on 3 different nonconsecutive days (order randomized) in 1 eye only. The subjects were screened to exclude those with dry eye. The lenses included a polymethyl methacrylate (PMMA) hard, a rigid gas permeable (RGP; Boston XO), and a soft silicone hydrogel lens. Three 30-second long high-speed videokeratoscopy recordings were taken with contact lenses in situ, in the morning and again after 8 hrs of contact lens wear, both in normal and suppressed blinking conditions. Recordings were also made on a baseline day with no contact lens wear.The presence of a contact lens in the eye had a significant effect on the mean TFSQ in both natural and suppressed blinking conditions (P=0.001 and P=0.01, respectively, repeated-measures analysis of variance). The TFSQ was worse with all the lenses compared with no lens in the eye in the afternoon during both normal and suppressed blinking conditions (all P<0.05). In natural blinking conditions, the mean TFSQ for the PMMA and RGP lenses was significantly worse than the baseline day (no lens) for both morning and afternoon measures (P<0.05).This study shows that both rigid and soft contact lenses adversely affect the TFSQ in both natural and suppressed blinking conditions. No significant differences were found between the lens types and materials.