About the optic disc size

Aim. To compare the dependence of retinal nerve fibre layer thickness on the optic disc size in confocal scanning laser ophthalmoscopy and optical coherence tomography. Methods. 201 outpatient’s cards with verified diagnosis of glaucoma or with suspicion of glaucoma were retrospectively analyzed. The mean age of the patients was 64 (56; 72) years [Me, (Q1; Q3)]. A group of patients who underwent confocal scanning laser ophthalmoscopy (181 eyes), and a group who underwent optical coherence tomography (183 eyes), were separated. Besides, all the groups were twice divided into 3 subgroups each, by means of cluster analysis and on the basis of size classification: large, medium and small. Results. According to the data of confocal scanning laser ophthalmoscopy, the bigger is the optic disc, the thinner is retinal nerve fibre layer (Rs=-0.22; р=0.001). In optical coherence tomography, different correlation was observed, the bigger is the optic disc, the thicker is the retinal nerve fibre layer (Rs=0.15; р=0.03). Conclusion. The size of the optic disc was related to the retinal nerve fibre layer thickness in both examination modes: there was an inverse relation found in confocal scanning laser ophthalmoscopy - the bigger the optic disc, the thinner is the retinal nerve fibre layer), and there was a direct dependence found in optical coherence tomography (the bigger is the optic disc, the thicker is retinal nerve fibre layer), thus it is important to consider the size of the optic disc while estimating the retinal nerve fibre layer thickness.

glaucoma, confocal scanning laser ophthalmoscopy, optical coherence tomography, retinal nerve, fibre layer, optic disc