Effects of cataract on peripapillary retinal nerve fibre layer and ganglion cell‐inner plexiform layer thickness measurement by cirrus optical coherence tomography

Abstract

Aims/Purpose: To assess the effect of cataract on peripapillary retinal nerve fibre layer (pRNFL) thickness and macular ganglion cell‐inner plexiform layer (mGC‐IPL) thickness measured by Cirrus (Carl Zeiss Meditec, Dublin, California, USA) spectral domain–optical coherence tomography (OCT).Methods: Cirrus OCT was used to measure the pRNFL thickness and mGC‐IPL thickness in 44 patients (63 eyes) patients with cataract, including 43 glaucoma eyes. Cataracts were graded according to the Lens Opacities Classification System III. The study aimed to identify factors that could contribute to segmentation errors and variations in the signal strength index (SSI) or average thickness of mGC‐IPL and pRNFL.Results: The prevalence of preoperative segmentation error were higher in pRNFL measurements compared with mGC‐IPL measurements (36.5% vs. 19.0%, p = 0.046). Multivariate analysis showed that segmentation error in RNFL measurements was significantly associated with preoperative SSI. Multivariate analysis indicated that preoperative SSI was highly correlated with changes with average thickness changes of mGC‐IPL and pRNFL.Conclusions: Among eyes with cataract, the occurrence of segmentation errors was more common in measurements of the pRNFL compared to measurements of mGC‐IPL. Following cataract surgery, there was a slight increase in all thickness parameters in both mGC‐IPL and pRNFL measurements, although the differences were not statistically significant (p = 0.102 and p = 0.151, respectively). It is important to identify segmentation errors, particularly in pRNFL measurements of eyes with cataract and low SSI.