2M.D. Associate Professor, Beyoglu Training and Research Hospital, Eye Clinic, Istanbul/TURKEY
3M.D. Professor, Beyoglu Training and Research Hospital, Eye Clinic, Istanbul/TURKEY Purpose: To evaluate the parameters of optic nerve head (ONH) and retinal nerve fiber layer (RNFL) in healthy patients with large optic disc area and to compare these parameters with those of the normal and early glaucoma patients.
Material and Methods: Ninety two eyes with physiological macrodiscs (PM), age-matched 92 eyes with normal eyes and 50 eyes with early glaucoma (EG) findings were enrolled. After a complete ophthalmic evaluation, measurement of optic nerve head parameters and RNFL thickness using OCT was performed in all subjects. Optic disc areas larger than 2.80 mm2 were accepted as macrodiscs. All OCT parameters were compared between normal-sized discs and macrodiscs. Central corneal thickness, intra ocular pressure and axial length measurements were found to be similar between 3 groups.
Results: Mean optic disc area of PM and EG were similar and larger than the control group. Rim area of EG group was thinner than the other groups (p=0.022, p=0.0001). Also, EG group had larger horizontal cup disc ratio, vertical cup disc ratio and cup disc area ratio (p>0.001). Average,superior and inferior RNFL thicknesses were thinner in the EG group (p<0.05).
Conclusion: Macrodisc may have a macrocup and should not be misdiagnosed as glaucoma. The present study showed that macrodiscs are identical to normal-sized discs in terms of rim area and RNFL thickness. We suggest that these 2 OCT parameters can help to differentiate a healthy macrodisc from a glaucomatous optic disc.
Keywords : Optical coherence tomography, glaucoma, large optic disc, macrodisc, optic nerve head analysis