Gupta Vinay, Bari Aafreen, Anjum Shahnaz, Yadav Ankit, Saxena Rohit, Sinha Rajesh
Dr. R. P. Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
Ophthalmic Physiol Opt. 2025 May;45(3):769-778. doi: 10.1111/opo.13456. Epub 2025 Feb 10.
This study aimed to quantify the internal, corneal and total higher order aberrations (HOAs) in the healthy human eye using ray tracing technology in bright and dim light conditions. The study also aimed to evaluate the retinal image quality and contrast modulation at different spatial frequencies, objectively using image-quality metrics derived from wavefront aberrations.
A cross-sectional prospective observational study was conducted on 521 emmetropic young adults. HOAs including coma, trefoil, spherical aberration and secondary astigmatism were measured separately for the cornea, internal and total eye using a ray-tracing wavefront aberrometer at mesopic and photopic pupil sizes. The Strehl ratio, derived from the point spread function (PSF), was used to evaluate the retinal image quality of the eye. Contrast modulation at spatial frequencies of 5, 10 and 15 cycles per degree was assessed through the modulation transfer function (MTF).
Mean age of participants was 25.4 ± 4.8 years (54.5% male). The total HOAs of internal, corneal and total eye were 0.186 ± 0.075, 0.191 ± 0.112 and 0.222 ± 0.075 μ, respectively for a 5-mm pupil (dim light condition), and 0.069 ± 0.031, 0.061 ± 0.094 and 0.076 ± 0.031 μ, respectively, for a 3-mm pupil (bright light condition). The Strehl ratio was 0.16 ± 0.124 (5 mm pupil) and 0.601 ± 0.19 (3 mm pupil). A normative database was created and correlations drawn for the HOAs, PSF and MTF (using image quality metrics) for the cornea, internal and total eye at mesopic and photopic pupil sizes.
These findings provide normal population (young healthy adults) reference ranges for HOAs, retinal image quality and contrast modulation at higher spatial frequencies using ray tracing technology. The presence of these natural wavefront aberrations enhances the visual performance and may not need to be corrected. The separate assessment of aberrations and derived image quality metrics for the cornea, internal and total eye can serve as a benchmark for diagnosing and monitoring ocular conditions and allows targeted treatment planning.
本研究旨在利用光线追踪技术，在明视和暗视条件下，对健康人眼的内部、角膜和总的高阶像差（HOAs）进行量化。该研究还旨在使用从波前像差导出的图像质量指标，客观地评估不同空间频率下的视网膜图像质量和对比度调制。
对521名正视的年轻成年人进行了一项横断面前瞻性观察研究。使用光线追踪波前像差仪，在中视和明视瞳孔大小下，分别测量角膜、眼内部和全眼的HOAs，包括彗差、三叶草像差、球差和继发性散光。由点扩散函数（PSF）得出的斯特列尔比，用于评估眼睛的视网膜图像质量。通过调制传递函数（MTF）评估每度5、10和15周期空间频率下的对比度调制。
参与者的平均年龄为25.4±4.8岁（男性占54.5%）。对于5毫米瞳孔（暗视条件），眼内部、角膜和全眼的总HOAs分别为0.186±0.075、0.191±0.112和0.222±0.075微米；对于3毫米瞳孔（明视条件），分别为0.069±0.031、0.061±0.094和0.076±0.031微米。斯特列尔比在5毫米瞳孔时为0.16±0.124，在3毫米瞳孔时为0.601±0.19。建立了一个标准数据库，并得出了中视和明视瞳孔大小下，角膜、眼内部和全眼的HOAs、PSF和MTF（使用图像质量指标）之间的相关性。
这些研究结果为使用光线追踪技术的HOAs、视网膜图像质量以及更高空间频率下的对比度调制，提供了正常人群（年轻健康成年人）的参考范围。这些自然波前像差的存在提高了视觉性能且可能无需矫正。对角膜、眼内部和全眼的像差及导出的图像质量指标进行单独评估，可作为诊断和监测眼部疾病的基准，并有助于制定有针对性的治疗方案。
