Evaluating the effect of pupil dilation on spectral-domain optical coherence tomography measurements and their quality score

Background: Spectral-domain optical coherence tomography (SD-OCT) provides fast scan speed and high scan resolution improving its diagnostic accuracy. The purpose of this study was to evaluate if SD-OCT measurements and their quality score are influenced by pupil dilation. Methods: Retinal nerve fiber layer thickness (RNFL), ganglion cell complex (GCC) and optic nerve head (ONH) were measured in one eye of 57 glaucoma patients and 36 healthy subjects using spectral domain optical coherence tomography (SD-OCT) before and after pupil dilation. Comparisons were made between measurements and their quality score pre- and post dilation (Signal Strength Index, SSI). Overall RNFL, average GCC and ONH rim volume were considered in the analysis. Results: No statistically significant differences were found between pre- and post-dilation measurements in both groups (glaucoma: RNFL 80 ± 15 μm vs 80 ± 16 μm, p = 0.87; GCC 81.35 ± 13.4 μm vs 81.10 ± 13.14 μm, p = 0.92; ONH 0.05 ± 0.11 mm3 vs 0.04 ± 0.07 mm3, p = 0.74; controls RNFL 99 ± 12 μm vs 98 ± 14 μm, p = 0.70; GCC 92.12 ± 6.7 μm vs 91.54 ± 7.05 μm, p = 0.72; ONH 0.11 ± 0.1 mm3 vs 0.04 ± 0.07 mm3, p = 0.36) nor between pre- and post-dilation quality score (glaucoma SSI RNFL 54.3 ± 10.3 vs 51.7 ± 18.1, p = 0.12; SSI GCC 58 ± 9.5 vs 57 ± 8.09, p = 0.55; SSI ONH 48.5 ± 7.6 vs 46.6 ± 7.2, p = 0.16; controls SSI RNFL 57 ± 10.3 vs 54 ± 9.31, p = 0.2; SSI GCC 60.9 ± 8.1 vs 58.8 ± 7.3, p = 0.3; SSI ONH 51.5 ± 8.9 vs 50.4 ± 8.3, p = 0.59). Conclusion: Pupil dilation doesn't affect SD-OCT measurements and their quality score.