University Eye Hospital Freiburg, Germany.
Invest Ophthalmol Vis Sci. 2011 Jun 28;52(7):4551-9. doi: 10.1167/iovs.10-6882.
In vivo imaging of the retina is becoming an increasingly important research method. General anesthesia rapidly compromises the corneal surface, which increases scattering. In addition, wavefront aberrations limit the maximum imaging resolution. Three common methods of stabilizing the air-cornea interface and reducing scattering are the use of a contact lens, a microscopy slide coverslip, or mineral oil. These methods have not yet been analyzed regarding their impact on scattering and wavefront aberrations.
Nineteen eyes of 19 rats were analyzed with a custom-made Hartmann-Shack (HS) wavefront sensor. The amount of scattering was determined by analysis of the HS spot width, and the wavefront was reconstructed for the naked eye and each scattering-reducing method. Their effect on optical quality was determined by calculating the modulation transfer function (MTF).
The three methods applied significantly reduced scattering but were differentially effective, with the coverslip performing the best and the mineral oil the worst. The root mean square (RMS) of the wavefront aberration, as well as the intereye variability of the RMS, was significantly smaller with the contact lens than with the coverslip. The MTF was best for the contact lens and worst for the coverslip, which was also illustrated by image simulations.
The coverslip, contact lens, and mineral oil, when applied to the cornea, all reduced scattering. The best-performing method, the coverslip, increased wavefront aberrations. Overall, the contact lens had the best influence on image quality, and it appears to be the method of choice for high-resolution retinal imaging in rats.
视网膜的活体成像正成为一种越来越重要的研究方法。全身麻醉会迅速损害角膜表面，从而增加散射。此外，波前像差限制了最大成像分辨率。稳定气-角膜界面和减少散射的三种常用方法是使用接触镜、显微镜盖玻片或矿物油。这些方法尚未分析其对散射和波前像差的影响。
使用定制的哈特曼-夏克（HS）波前传感器分析了 19 只大鼠的 19 只眼睛。通过分析 HS 光斑宽度来确定散射量，并用裸眼和每种降低散射的方法重建波前。通过计算调制传递函数（MTF）来确定它们对光质量的影响。
三种方法均显著降低了散射，但效果不同，盖玻片效果最好，矿物油效果最差。接触镜的均方根（RMS）波前像差以及 RMS 的眼间可变性均明显小于盖玻片。接触镜的 MTF 最好，盖玻片最差，图像模拟也说明了这一点。
应用于角膜的盖玻片、接触镜和矿物油均降低了散射。表现最佳的方法——盖玻片增加了波前像差。总的来说，接触镜对图像质量的影响最好，似乎是大鼠高分辨率视网膜成像的首选方法。
