Purpose : To determine the nerve fiber layer and macular thickness by optical coherence tomography (OCT) in emmetropic, high-myopic and high-hyperopic eyes

Methods : One hundred five eyes of 55 randomly selected healthy subjects between 20 and 30 years old were included in this study. The eyes were categorized in three groups (high-myopic, emmetropic and high-hyperopic) according to their cycloplegic refraction and axial length ( AL ). The retinal nerve fiber layer (RNFL) and macular thickness was measured using three circumferential peripapillary scans and six radial scans of the macula by optical coherence tomography (OCT model 2010, Zeiss). Average RNFL thickness in the peripapillary region and macular thickness was measured and compared in these three groups.

Results : Mean age of participants was 24.3±2.6 years. Average RNFL thickness was 107.9±8.3 µ, 131.1±3.2 µ and 145.8±2.8 µ in high-myopic, emmetropic and high-hyperopic groups, respectively. There was a high correlation between RNFL thickness and AL (r= -0.91, p<0.001). Average inner macular thickness was 221.6±13.2 µ, 246±10.5 µ and 255.9±15.0 µ and average outer macular thickness was 207.6±9.7 µ, 230.1±7.4 µ and 239.7±13.0 µ in high-myopic, emmetropic and high-hyperopic groups, respectively. The difference of RNFL thickness was statistically significant between these three groups.

Conclusion : High-hyperopic eyes had significantly thicker average RNFL thickness than emmetropic and high-myopic eyes; while emmetropic eyes had thicker average RNFL thickness than high-myopic eyes. There is a strong negative correlation between AL and average NFL thickness.