Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Road no. 2, Banjara Hills, Hyderabad, 500034, Telangana, India.
Prof. Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L V Prasad Eye Institute, Road no. 2, Banjara Hills, Hyderabad, 500034, Telangana, India.
Sci Rep. 2020 Jan 28;10(1):1321. doi: 10.1038/s41598-020-57993-w.
Higher-order aberrations (HOA's) are exaggerated in eyes with keratoconus but little is known about their impact on the retinal image quality (IQ) of these eyes. This computational study determined changes in IQ [peak IQ, best focus and depth of focus (DOF)] of 12 subjects with manifest keratoconus in both eyes (KCE cohort), 9 subjects with very asymmetric ectasia (VAE cohort) with and without their Rigid Gas Permeable contact lenses (RGP CL's) and 20 age-matched controls, using a HOA-based through-focus analysis performed on the logNS IQ metric over 5 mm pupil diameter following cycloplegia. All IQ parameters were significantly worse in the KCE cohort with their native HOA's, relative to controls and in the ectatic eye of the VAE cohort, relative to the fellow non-ectatic eye (p ≤ 0.008 for all). Reduction in HOA's of these eyes with RGP CL's resulted in a significant improvement in all IQ parameters but they all remained significantly poorer than controls (p ≤ 0.02 for all). The inter-subject variability of best focus and the DOF range were inversely related to peak IQ in these eyes (r = 0.85; p < 0.001). These results provide the optical basis for two clinical observations on keratoconus: (1) optical performance of keratoconic eyes are significantly better with RGP CL's than with spectacles or unaided conditions and (2) the endpoint of subjective refraction is elusive in keratoconic eyes, relative to healthy controls or to the non-ectatic eye in bilaterally asymmetric ectasia.
高阶像差（HOA）在圆锥角膜眼中会被夸大，但对于这些眼睛的视网膜图像质量（IQ）的影响知之甚少。本计算研究确定了 12 名双眼明显圆锥角膜患者（KCE 队列）、9 名角膜不规则散光患者（VAE 队列）及其硬性透气性隐形眼镜（RGP CL）的 IQ [峰值 IQ、最佳焦点和景深（DOF）]的变化，以及 20 名年龄匹配的对照者，使用基于 HOA 的通过焦点分析在环戊酮麻痹后对 logNS IQ 指标进行 5mm 瞳孔直径的分析。与对照组相比，KCE 队列的所有 IQ 参数在其原生 HOA 时均明显更差，与 VAE 队列的非病变眼相比，其病变眼也更差（所有 p 值均≤0.008）。这些眼睛的 HOA 减少与 RGP CL 的使用可导致所有 IQ 参数的显著改善，但与对照组相比，它们仍然明显较差（所有 p 值均≤0.02）。这些眼睛的最佳焦点和景深范围的个体间变异性与峰值 IQ 呈负相关（r=0.85；p<0.001）。这些结果为圆锥角膜的两个临床观察提供了光学依据：（1）与眼镜或未矫正条件相比，RGP CL 可显著改善圆锥角膜眼的光学性能，（2）与健康对照组或双侧不对称性散光的非病变眼相比，圆锥角膜眼的主观折射终点难以捉摸。
