ABSTRACT
PURPOSE: To evaluate the influence of pupil dilation on retinal nerve fibre layer (RNFL) measurements with spectral domain optical coherence tomography (OCT). PATIENTS AND METHODS: In total, 29 healthy individuals and 26 glaucoma patients underwent RNFL measurements with the Cirrus HD-OCT Model 4000 (Carl Zeiss Meditec Inc.) before and 30-40 min after pupil dilation with one drop of tropicamide 1%. Average thickness, quadrant thickness, and clock-hour thickness measurements were compared with the paired Student's t-test. We also compared the quality scores of the images obtained pre- and post-pupil dilation. RESULTS: Mean ages in the glaucoma and control groups were 58.3+/-13.4 and 41.6+/-16.4 years respectively (P<0.001). Mean deviation values were -6.96+6.31 dB in the glaucoma group and -1.26+0.79 dB in the control group (P<0.001). Mean RNFL measurements obtained in the glaucoma group were significantly lower than those obtained in the control group (P<0.001). There were no statistically significant differences between mean quality scores obtained before and after dilation neither in the glaucoma group (7.73+/-0.92 vs 7.54+/-1.10, P=0.232) nor in the control group (8.14+/-0.88 vs 8.00+/-0.71, P=0.380). There was no statistically significant difference between mean RNFL measurements obtained pre- and post-pupil dilation neither among normal individuals (P>0.05), nor among glaucoma patients (P>0.05). CONCLUSION: The results of this study indicate that RNFL measurements obtained with spectral domain OCT are not influenced by pupil size.