Effects of long-term topical prostaglandin therapy on central corneal thickness.

PURPOSE Recent studies have shown that prostaglandin analogues can decrease the central corneal thickness (CCT), however, most of those studies followed the patient's CCT for only approximately 2 years. The purpose of this present study was to perform a long-term follow-up investigation of CCT in patients who underwent only topical prostaglandin monotherapy over 4 years, and then analyze the CCT changes and the correlation between intraocular pressure (IOP) changes and CCT changes. METHODS This retrospective study involved 52 eyes of 52 glaucoma patients who consulted with glaucoma specialists at the Glaucoma Clinic of Kyoto Prefectural University of Medicine, Kyoto, Japan and underwent latanoprost eye drop monotherapy for more than 4 years in at least 1 eye between 2005 and 2011. In all patients, CCT was evaluated by the Pentacam(®) Scheimpflug system at pretreatment, midpoint, and final follow-up. The Student's t-test was used to analyze the CCT changes. RESULTS The mean CCT significantly decreased from 537 ± 34 μm at pretreatment to 526 ± 32 μm at the final follow-up (P<0.0001). Interestingly, no significant difference was found between the mean CCT at midpoint and that at final follow-up (P=0.17), yet the mean CCT significantly decreased to 529 ± 32 μm in the first 2 years (P=0.0015). No correlation was found between IOP and CCT reduction. CONCLUSIONS The findings of this study show that latanoprost eye drops significantly reduce CCT during the initial stage of use, however, CCT reduction does not clinically affect IOP values.