The investigation of retinal nerve fiber layer thickness in eyes with optic nerve head drusen

Purpose: To investigate the effect of optic nerve head drusen (ONHD) on the retinal nerve fiber layer (RNFL) thickness. Patients and methods: Twenty-one nonglaucomatous eyes with various degrees of ONHD and 27 age-matched control eyes were included in the study. Visual fields and RNFL thickness were assessed using Humphrey field analyzer and optical coherence tomography (OCT), respectively. The eyes with various degrees of ONHD and the control eyes were compared with regard to visual field (VF) indices and RNFL thicknesses. Results: VF indices of the eyes with ONHD were significantly different from those of the control eyes (p < 0.05), but no significant difference existed among the eyes with various degrees of ONHD (p > 0.05). The RNFL thicknesses of inferior quadrants of the eyes with ONHD were significantly thinner than those of the control eyes (p < 0.05). A significant thinning of the RNFL in the superior and nasal quadrants was observed in grade II and III discs, while temporal quadrants only in grade III discs presented a similar change (p < 0.05). A comparison between the RNFL thicknesses of various degrees of ONHD did not show a significant statistical difference (p > 0.05) except for the thickness in the temporal RNFL (p < 0.05). Conclusion: We found a significant decrease in the RNFL thickness of ONHD patients compared to that of the control subjects. The measurements of VF indices did not show a significant difference between various degrees of ONHD. In contrast, RNFL thickness was significantly correlated with the amount of ONHD. This suggests that OCT may allow the detection of early changes in RNFL thickness in ONHD patients before observable changes in the visual field are seen.