Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.
Faculty of Medicine and Health Sciences, Antwerp University, Wilrijk, Belgium.
Ophthalmic Physiol Opt. 2022 Mar;42(2):358-366. doi: 10.1111/opo.12931. Epub 2021 Dec 11.
To expand the SyntEyes keratoconus (KTC) model to assess the Visual Image Quality (VIQ) of sphero-cylindrical spectacle and rigid contact lens corrections as keratoconus progresses.
The previously published SyntEyes KTC eye model to determine best sphero-cylindrical spectacle and rigid contact lens correction in keratoconic eyes was expanded to include the natural progression of keratoconus, thus allowing the assessment of corrected VIQ with disease progression.
As keratoconus progresses, the pattern of visual Strehl ratio (VSX) in correction space for spectacles alters from a typical hourglass into a shell pattern. The former would guide the subjective refraction towards the optimal correction while the latter is relatively insensitive to large dioptric steps. In 15 out of the 20 SyntEyes, the shell pattern eventually produces two foci on different sides of the correction space separated by a clinically significant dioptric difference with a similar, albeit lower VIQ. Wearing the best possible spectacle corrections provided an average gain of up to 3.5 lines of logMAR visual acuity compared to the uncorrected cases, which increased to 5.5 lines for the best rigid contact lens correction. Continuing to wear a spectacle correction as the disease progresses often leads to a VIQ that is almost as bad as the uncorrected case. Continuing to wear a rigid contact lens correction as the disease progresses maintains a relatively high level of VIQ, albeit in the low range for typically well-corrected normal eyes.
The results reflect the clinical experience that subjective refraction is difficult in highly-aberrated keratoconic eyes, the benefit of spectacle correction is short lived and that rigid contact lenses provide better and more stable VIQ with disease progression. Other aspects, such as the presence and behaviour of the second focus in some cases, remain to be confirmed clinically.
扩展 SyntEyes 圆锥角膜 (KTC) 模型，以评估圆锥角膜进展过程中球柱镜矫正视力和硬性透气性角膜接触镜矫正视力的视觉图像质量 (VIQ)。
先前发表的用于确定圆锥角膜眼中最佳球柱镜矫正视力和硬性透气性角膜接触镜矫正视力的 SyntEyes KTC 眼模型被扩展到包括圆锥角膜的自然进展，从而允许在疾病进展的情况下评估矫正后的 VIQ。
随着圆锥角膜的进展，矫正空间中的视觉斯特雷尔比 (VSX) 模式从典型的沙漏形变为壳形。前者将指导主观验光向最佳矫正方向发展，而后者对大屈光度步长相对不敏感。在 20 个 SyntEyes 中的 15 个中，壳形模式最终会在矫正空间的两侧产生两个焦点，它们之间的临床显著屈光度差异很大，而 VIQ 则相似，尽管较低。佩戴最佳的眼镜矫正可以比未矫正的情况下平均提高高达 3.5 行 logMAR 视力，而最佳硬性透气性角膜接触镜矫正则提高到 5.5 行。随着疾病的进展继续佩戴眼镜矫正通常会导致 VIQ 几乎与未矫正的情况一样差。随着疾病的进展继续佩戴硬性透气性角膜接触镜矫正可以保持相对较高的 VIQ，尽管在典型矫正良好的正常眼中处于低水平。
结果反映了临床经验，即高度像差的圆锥角膜眼中主观验光困难，眼镜矫正的效果短暂，而硬性透气性角膜接触镜在疾病进展时提供更好和更稳定的 VIQ。其他方面，如在某些情况下第二个焦点的存在和行为，仍有待临床证实。
