Faculty of Life Sciences, University of Manchester, Manchester, UK.
Ophthalmic Physiol Opt. 2012 Nov;32(6):485-91. doi: 10.1111/j.1475-1313.2012.00935.x. Epub 2012 Sep 7.
To explore theoretically the ocular components that might be responsible for the transient refractive changes observed in the eyes of diabetic patients, particularly during intensive glycaemic control.
Paraxial ray tracing with a model eye having a lens with a single equivalent refractive index was used to determine the sensitivity of refraction to change in the values of each biometric component. The changes required to produce a refractive change of 0.50 D were compared with the reliability of current instrumentation to measure each parameter.
If transient shifts of 0.50 D or more were caused by changes in surface curvatures or separations, the latter would easily be detectable by available measurement techniques. The fact that such parameter changes have not been reliably detected in clinical studies supports the concept that changes in refractive index cause the refractive changes. The most probable site of such index changes is the lens, a change of about 0.003 in equivalent index being required to produce a 0.50 change in refractive error.
This analysis supports the concept that transient changes in refraction in diabetics are due to changes in the lens. It is likely that changes in the gradients of refractive index lens within the lens, and in their associated contribution to the overall power of the lens, play the key role, rather than changes in surface powers.
从理论上探讨可能导致糖尿病患者眼球发生短暂屈光变化的眼部结构，尤其是在强化血糖控制期间。
采用模型眼的傍轴光线追踪技术，该模型眼的晶状体具有单一等效折射率，用于确定折射对每个生物计量学参数值变化的敏感程度。比较产生 0.50 D 折射变化所需的变化与当前测量每个参数的仪器的可靠性。
如果表面曲率或分离的变化导致 0.50 D 或更大的瞬时位移，则当前的测量技术可轻松检测到后者。事实上，临床研究尚未可靠地检测到这些参数变化，这支持了折射指数变化导致折射变化的概念。折射率变化最可能发生在晶状体，晶状体等效指数的约 0.003 变化即可导致 0.50 的屈光误差变化。
该分析支持了糖尿病患者的短暂屈光变化是由于晶状体变化引起的概念。很可能是晶状体内部的折射率梯度变化及其对晶状体整体屈光力的相关影响起着关键作用，而不是表面屈光力的变化。
