Morphometric characteristics of optic disc in patients with myopia and primary open-angle glaucoma.

BACKGROUND/AIM: Primary open-angle glaucoma is a multifactorial and progressive neuropathy, characterised by the acquired loss of ganglion cells of the retina and their axons. One of the risk factors for primary open-angle glaucoma is myopia over 5 diopters (D). The aim of our work was to investigate two groups of patients with primary open-angle glaucoma and myopia by using confocal scanning laser ophthalmoscopy, and to find out if the size of refractive error influences optic disk morfometric characteristics.

METHODS

One hundred eyes of one hundred patients with primary open-angle glaucoma and myopia were involved in our study. All the patients were classified into two groups, the first one with myopia < 5 D, and the second one with myopia > or = 5 D. The Heidelberg retina tomograph is a technique we used in our study. We analized morfometric parameters of patients optic discs, with the aim to find a correlation between the parameters in each group separeatly, and also to find differences between the same parameters from both groups.

RESULTS

There were significant differences in disc area, cup area, rim area and mean RNFL thickness between the two groups. The size of damage of neuroretinal rim in the group with high myopia was 27%, and in the group with lower myopia 14%. The most frequently damaged segment of neuroretinal rim in the patients with high myopia was nasal segment and in the patients with low myopia infero-temporal one. The least frequently damaged segment of neuroretinal rim in both groups was temporal one.

CONCLUSION

Optic discs of glaucomatous patients with high myopia have bigger diameter, also bigger and more irregularly distributed damaged zone of neuroretinal rim, and also thinner retinal nerve fiber layer compared to glaucomatous patients with lower myopia.