Effect of topical prostaglandins on the biomechanics and shape of the cornea

Purpose To investigate the effect of topical prostaglandin (PG) eyedrops on the biomechanics and shape of the cornea. Methods Consecutive patients with primary open-angle glaucoma who had been treated with the same anti-glaucoma PG (114 eyes, 57 patients) or beta-blocker (36 eyes, 18 patients) eyedrops in 1 eye alone for more than 3 months at Inouye Eye Hospital or Miyata Eye Hospital. The biomechanical properties of the cornea were measured using a Corvis ST device (Oculus, Wetzlar, Germany). Corneal tomography was measured with a Casia 1 or 2 (Tomey Corp., Nagoya, Japan). The biomechanical parameters and tomographic features of the cornea were compared between PG-treated eyes, beta-blocker-treated eyes, and contralateral eyes using a mixed-effect model adjusted for intraocular pressure and corneal thickness and a linear model adjusted for age, sex, intraocular pressure, and corneal thickness. Results The PG-treated eyes had a significantly smaller applanation 1 time, the highest concavity radius, and a larger deformation amplitude than the contralateral eyes. Also, the PG-treated eyes had a significantly smaller applanation 1 time and applanation 2 velocity but a larger peak distance than the beta-blocker-treated eyes. There were no significant differences in any of the Casia parameters between the PG-treated eyes and the contralateral eyes. Conclusion The results of this study suggest that topical PG makes biochemical changes to the cornea but does not alter its shape.