Keratoconus has been known as a non-inflammatory, progressive ectatic disorder characterised by corneal thinning more prominently in the inferior zone.1 The prevalence of keratoconus is increasing ...

Background: Previous studies revealed that optical coherence tomography (OCT) and visual evoked potential (VEP) were impaired in patients with Parkinson’s disease (PD), but the results were inconsistent; in this meta‐analysis, we tried to answer this issue by including studies that performed these two tests on the same sample size. Methods: PubMed, Scopus, Cochrane, and Google Scholar were comprehensively reviewed to retrieve the published studies investigating changes in OCT and VEP responses in PD patients. We analyzed the pooled weighted difference in means between PD patients and healthy controls using the random‐effects model. Results: Ten studies were included (12 sets of data), enrolling 337 PD patients and 273 healthy controls. The P100 latency in PD patients was significantly higher compared to healthy controls (difference in means = 6.16, 95% CI: 1.16–11.15, p = 0.02, n = 11). Significant thinning of the retinal nerve fiber layer (difference in means = −4.38, 95% CI: −6.29 to −2.47, p ≤ 0.001, n = 11) was observed in the PD eyes compared to the healthy subjects. However, no statistically significant difference was found in the means of P100 amplitude ( p = 0.06) and the average central foveal thickness ( p = 0.08) between PD patients and the control group. There was a significant negative correlation between RNFL weighted mean difference and P100 latency ( r = −0.65, p ≤ 0.001) in all subjects. Conclusions: Our results confirmed that Parkinson’s patients showed significant thinning of RNFL thickness and prolonged P100 latency time.

Purpose: To investigate differences in corneal and ocular aberrations between hyperopic, emmetropic, and myopic eyes. Methods: This cross-sectional study included 84 eyes from 84 healthy participants (age range 18-35 years), who were equally divided into three refractive error groups of hyperopia, emmetropia, and myopia. Following comprehensive optometric examinations, corneal and ocular aberrations were measured using Pentacam and Zywave imaging systems, respectively. Aberrations were measured for a pupil diameter of 5 mm. Root-mean-square (RMS), Zernike coefficients, and compensation factor (CF) between total ocular and corneal aberrations were calculated for statistical analysis. Results: The mean spherical equivalent was +1.96 ± 1.64, –0.17 ± 0.19, and –2.46 ± 1.56 diopters in hyperopic (H), emmetropic (E), and myopic (M) eyes, respectively. The amount of corneal Zernike coefficients Z4–2 in the hyperopic eyes (H: 0.015 ± 0.040) was significantly higher than that of emmetropic eyes (E: –0.018 ± 0.054) and myopic eyes (M: –0.003 ± 0.038) with a P-value of 0.029. The RMS of corneal total coma (H: 0.228 ± 0.097, E: 0.183 ± 0.086, M: 0.164 ± 0.083, P-value: 0.009, respectively) and RMS of ocular fifth-order (H: 0.045 ± 0.018, E: 0.036 ± 0.020, M: 0.032 ± 0.016, P-value: 0.002) showed a significant difference between refractive error groups, with higher value in hyperopic eyes compared to the two other groups. There was no significant difference in CF for RMS and Zernike coefficients among the refractive error groups. Conclusion: Hyperopic eyes showed a higher RMS value for ocular fifth-order and corneal coma aberrations compared to the emmetropic and myopic eyes.