Influence of pupil dilation on retinal nerve fibre layer measurements with spectral domain OCT.

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.

Central corneal thickness in children with congenital cataract and children with surgical aphakia: a case-control study.

AIM: To measure the central corneal thickness (CCT) of children with congenital cataract and surgical aphakia. METHODS: Children with congenital cataract or surgical aphakia were prospectively recruited and divided into four groups: unilateral cataract (group 1, n = 14), bilateral cataract (group 2, n = 17), unilateral aphakia (group 3, n = 32) and bilateral aphakia (group 4, n = 44). An age-, sex-, and race-matched control group of normal individuals was selected. Ultrasonic pachymetry was performed by the same observer. RESULTS: The mean CCT of the control group was not significantly different from the normal (p = 0.747) and cataractous eyes of group 1 (p = 0.252). The mean CCTs of both eyes of group 2 were significantly higher than the control group (p<0.01). The mean CCT of the aphakic eyes in group 3 was significantly higher than the contralateral healthy eyes and control eyes (p<0.001). The mean CCTs of both eyes of group 4 were significantly higher than the control group (p<0.001). The mean CCT was significantly higher in aphakic eyes of groups 3 and 4 than in cataractous eyes of groups 1 and 2 (p<0.001). CONCLUSIONS: Aphakic eyes due to congenital cataract show thicker corneas than normal phakic eyes. Aphakic eyes after congenital cataract extraction show thicker corneas than eyes with congenital cataracts, suggesting that the increase in CCT occurs postoperatively.