The influence of central corneal thickness on response to topical prostaglandin analogue therapy

• Published in: Canadian journal of ophthalmology 2012-02, Vol.47 (1), p.51-54
• Main Authors: Birt, Catherine M., MA, MD, FRCSC, Buys, Yvonne M., MD, FRCSC, Kiss, Alex, PhD, Trope, Graham E., MD, PhD, FRCSC
• Format: Article
• Language: English
• Subjects: Administration, Topical; Amides - administration & dosage; Antihypertensive Agents - administration & dosage; Bimatoprost; Cloprostenol - administration & dosage; Cloprostenol - analogs & derivatives; Cornea - drug effects; Cornea - pathology; Female; Glaucoma, Open-Angle - drug therapy; Glaucoma, Open-Angle - ethnology; Humans; Internal Medicine; Intraocular Pressure - drug effects; Male; Middle Aged; Ocular Hypertension - drug therapy; Ocular Hypertension - ethnology; Ophthalmology; Prospective Studies; Prostaglandins F, Synthetic - administration & dosage; Tonometry, Ocular; Travoprost; Treatment Outcome
• ISSN: 0008-4182; 1715-3360
• DOI: 10.1016/j.jcjo.2011.12.012

Abstract Objective Central corneal thickness (CCT) affects intraocular pressure (IOP) readings; however, CCT influence on topical medication efficacy is unknown. We evaluated the IOP-lowering effect of topical prostaglandin analogues (PGAs) in relation to CCT. Design Post hoc analysis of a randomized prospective trial. Method Subjects randomized to a PGA were followed for 24 weeks and were analyzed for relationship between CCT and IOP lowering. Participants Patients with either newly diagnosed ocular hypertension or open-angle glaucoma. Results 75 subjects were enrolled. The mean age was 62.7 ± 10.5 years; 48 were Caucasian. The mean CCT was 562.4 ± 41.4 μ. At repeated measures, ANCOVA analysis showed a significant effect of both baseline IOP ( p < 0.0001) and CCT ( p = 0.003) on IOP. At week 12, a regression analysis of the effect of CCT on baseline IOP showed that for every 10 μ increase in CCT there was 0.3 mm Hg less IOP decrease from baseline. Conclusions We found a statistically significantly association between a lower mean IOP and a thinner cornea when baseline IOP is controlled for. The magnitude of the relationship is small but may be clinically significant in patients with either very thin or very thick corneas.