Retinal layer thickness is decreased in glaucomatous eyes

"With this in mind, our research team conducted a study focusing on the role of the macula in glaucoma, analysing the configuration of the retinal layers to isolate any pathologic thinning in glaucomatous eyes and to identify the topographic distribution of any such thinning," he said. The results of the study were presented at the most recent annual congress of the European Association for Vision and Eye Research (EVER), which was held in Nice, France.

For the purposes of this study, the team were specifically interested in the retinal nerve fibre layer (RNFL), the retinal ganglion cell plus inner plexiform layer (RGIPL) and the retina as a whole. The central 5° area of the macula was then also divided into 65 segments for further evaluation.

"The maculae of healthy subjects (n = 112; age range: 20–76 years) were scanned with the Cirrus (Carl Zeiss Meditec, Jena, Germany) high definition optical coherence tomography (HD-OCT) instrument, and the 512 x 128 three-dimensional scans were then subjected to quantitative analysis using Matlab R2009b software (The Mathworks Inc., Cambridge, UK), which was developed by our research team," Dr Holzer added. Matlab R2009b locates and 'locks on' to the fovea to increase the accuracy of the positioning of the HD-OCT, as focusing is difficult for glaucoma patients; once the eye is in the correct position, the software automatically detects retinal layers without any manual correction required, which is unique.

He continued, "Using the thickness data we gathered from these scans of healthy eyes, we built colour-coded thickness maps and a normative database (taking into account the effects of age), against which we compared thickness data gathered from subjects with glaucoma of varying stages (n = 25; age range: 42–79 years)." Patients with pre-existing retinal neuropathy were excluded from the study.