Evaluation of prostaglandin analogue effects on corneal keratocyte density using scanning laser confocal microscopy

Purpose: To determine if treatment with prostaglandin (PG) analogues affects keratocyte density as an indirect measure of extracellular matrix in the corneal stroma. Patients and Methods: In this case control study, 129 eyes from 68 patients were examined: 52 eyes had only PG analogue therapy for at least 3 years, 37 eyes had only [beta]-adrenergic blocker therapy for at least 3 years, and 40 control eyes were without therapy. Scanning laser confocal microscopy was carried out, and each corneal stroma was subdivided into the anterior, midstroma, and posterior stroma. Keratocyte density was determined from the images by manual counting. Results: Keratocyte densities in the entire stroma and in 2 stromal layers were significantly higher in patients with PG analogue therapy compared with control patients (entire stroma, P<0.001; anterior stroma, P=0.001; posterior stroma, P=0.016). Keratocyte density in the PG analogue therapy patients was also greater compared with the [beta]-adrenergic blocker patients (entire stroma, P<0.001; anterior stroma, P