Influence of Cataract Surgery on Optical Coherence Tomography and Neurophysiology Measurements in Patients With Retinitis Pigmentosa

Abstract

To evaluate the effect of uncomplicated cataract phacoemulsification on the measurements of visual evoked potentials (VEP), pattern electroretinogram (PERG), and macular and retinal nerve fiber layer (RNFL) using 2 spectral-domain optical coherence tomography (OCT) instruments, the Cirrus OCT (Carl Zeiss Meditech) and Spectralis OCT (Heidelberg Engineering), in patients with retinitis pigmentosa (RP), and to assess the reliability of the OCT measurements before and after cataract surgery. Observational cross-sectional study. Thirty-five eyes of 35 patients with RP (20 men and 15 women, 45-66 years) who underwent cataract phacoemulsification were studied. At 1 month before and 1 month after surgery, visual acuity, VEP, PERG, and 3 repetitions of scans using the RNFL and macular analysis protocols of the Cirrus and Spectralis OCT instruments were performed. The differences in measurements between the 2 visits were analyzed. Repeatability of OCT measurements was evaluated by calculating the coefficients of variation. VEP amplitude, RNFL thicknesses provided by Cirrus and Spectralis, and macular measurements provided by Cirrus OCT differed between the 2 visits. VEP latency, PERG measurements, and macular thicknesses provided by the Spectralis OCT before surgery did not differ significantly from those after surgery. The OCT repeatability was better after surgery, with lower coefficients of variation for scans performed after surgical removal of the cataract. The nuclear, cortical, and posterior subcapsular types of cataracts did not show different repeatability. The presence of cataracts affects VEP amplitude, RNFL, and macular measurements performed with OCT in eyes with RP. Image repeatability significantly improves after cataract phacoemulsification.