Department of Physics, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Opt Lett. 2013 Mar 1;38(5):745-7. doi: 10.1364/OL.38.000745.
Imaging the retina at high resolution requires a dilated pupil, which in turn exposes more corneal irregularities. We diminish the optical errors of the cornea by refractive index matching. Lens-fitted goggles were used for corneal immersion, to reduce its aberrations, while keeping the ocular power. An additional aspheric plate reduced the residual ocular spherical aberration. A comparison of the index-matching-based retinal images with those acquired directly shows resolution improvement for subjects with normal extent of ocular aberrations. A simulation of the point spread function, obtained from an averaged ocular and corneal wavefront error, also reveals substantial improvement when using corneal index matching. The demonstrated improvement using index matching may enable further improvement of current retinal imaging techniques or relaxing requirements for active ocular aberration correction.
高分辨率视网膜成像需要散瞳，这会增加更多的角膜不规则性。我们通过折射率匹配来减少角膜的光学误差。使用配有镜片的护目镜进行角膜浸没，以减少其像差，同时保持眼内屈光力。附加的非球面板减少了残余的眼球差。基于折射率匹配的视网膜图像与直接获得的图像进行比较，结果显示对于眼像差正常范围的受试者，分辨率有所提高。通过对平均眼和角膜波前误差获得的点扩散函数进行模拟，也显示出使用角膜折射率匹配时的显著改善。折射率匹配的改进可能会进一步提高当前的视网膜成像技术，或放宽对主动眼像差校正的要求。
