gms | German Medical Science

To examine optic nerve head (ONH) characteristics with particular attention to asymmetry in optic disc parameters among healthy adults in a cross-sectional study using confocal laser scanning tomography and thereby to acquire new reference data.

Optic disc topography of both eyes was assessed with a confocal scanning laser ophthalmoscope (HRT I) among adults aged 35-70 years with no history of glaucoma, ocular hypertension or other ocular pathology. The examination included assessment of visual acuity, slitlamp examination, Goldmann tonometry and computerised perimetry. Eyes with ocular hypertension, glaucoma, papilla leporina or papilledema were excluded. Micro- and macropapillae were included. Means for both eyes and cumulative distribution curves for asymmetry of ONH measurements were calculated.

The study included 3866 eyes of 1933 Patients (684 females and 1249 males) with a mean age of 51.1 (SD 9.9) years and a mean refractive error measuring 0.12 (2.1) dioptres. Mean disc area was 1.84 (0.38) mm². Mean cup area measured 0.41 (0.30) mm². The standardised linear regression coefficient for cup- and disc area was r=0.68. Mean cup to disc area ratio was 0.208 (0.13). Rim area extended to 1.43 (0.28) mm² with a mean retinal nerve fiber layer thickness measuring 0.260 (0.07) mm. Mean disc area asymmetry between left and right eyes was 0.19 (0.16) mm² (without sign). Mean cup area asymmetry measured 0.14 (0.13) mm² whereas mean rim area asymmetry extended to 0.18 (0.16) mm². Forms and frequency of optic disc asymmetry were analyzed with regards to refraction, age and other parameters.

The presented results differ from published data on ONH topographies using various techniques. The presented data may describe a larger basis for comparison of ONH characteristics between healthy and glaucomatous eyes.