2M.D. Asistant, Abant İzzet Baysal University Faculty of Medicine, Department of Ophthalmology, Bolu/TURKEY
3M.D., Malatya EGM Hayat Hospital, Eye Clinic, Malatya/TURKEY
4M.D. Professor, Abant İzzet Baysal University Faculty of Medicine, Department of Ophthalmology, Bolu/TURKEY Purpose: To determine the retinal nerve fiber layer (RNFL) thickness and posterior pole analysis (PPA) and their repeatibility in healthy subjects using optical coherence tomography (OCT).
Materials and Methods: RNFL thickness and PPA were measured from the right eyes of 50 healthy subjects [25 (50%) male and 25 (50%) female] aged between 20 and 30 years. After the first measurement with default RNFL and PPA mode in random order, subjects withdrew their heads and rested for 10 sec and then the second measurements were taken. For statistical analysis of RNFL measurements, seven segments of the RNFL measurement mode of the instrument were evaluated. For statistical analysis of PPA measurements, the most temporal superior and most temporal inferior cells and central macular four cells of the 8x8 grid of PPA output were used. Statistical analyses of RNFL thickness and PPA differences were determined using the paired samples t-test and the repeatibility of the measurements was analyzed using the intra-class correlation coefficient (ICC).
Results: There was no statistically significant difference between the first and the second measurements of all evaluated segments of RNFL and PPA (p values ranged between 0.06 and 0.91). ICC values for the first and the second RNFL and PPA measurements ranged between 0.90 and 0.99.
Conclusion: RNFL and PPA measurements using OCT have high repeatability in healthy subjects.
Keywords : Optical coherence tomography, posterior pole analysis, repeatability, retinal nerve fiber layer