Abstract
Purpose: :
To evaluate whether treatment with prostaglandin analogs, because of upregulation of matrix metalloproteinases, affects keratocyte density, considered as indirect measure of extracellular matrix in corneal stroma.
Methods: :
In this observational case series study, 129 eyes from 68 patients were examined: 52 eyes in therapy with prostaglandin analogs at least from 3 years (first group), 37 eyes in therapy with beta-blockers at least from 3 years (second group) and 40 control eyes without therapy (third group). Confocal microscopy was performed using Heidelberg Retina Tomograph II Rostock Corneal Module. Each corneal stroma was subdivided in three layers: the anterior stroma (AS) was up to 33% of stromal depth, the mid stroma (MS) was from 34% to 66% of stromal depth and the posterior stroma (PS) was down to 100% of stromal depth. Keratocyte density was determined by manual counting method, using the software provided with Rostock Corneal Module.
Results: :
Keratocytes density resulted significantly higher in patients with prostaglandin analogs therapy compared to control patients (in AS p=0,001, in MS p= 0,079, in PS p=0,016) and compared to patients with beta-blockers therapy (in AS p=0,0001, in MS p=0,023, in PS p=0,007), while no statistically significant differences were found between control and beta-blockers groups. Considering prostaglandin anologs group, p values seem to suggest that the therapy affects primarily anterior stroma.
Conclusions: :
The present results suggest that chronic topical application of prostaglandin analogs in glaucomatous patients increases keratocyte density as a possible consequence of the decrease of extracellular matrix. Keratocyte density is increased in each layer of corneal stroma, but more significantly in the anterior stroma than in the mid and posterior one, probably for the topic application of the drugs with higher concentration at this level.
Keywords: cornea: stroma and keratocytes • extracellular matrix • drug toxicity/drug effects