Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Department of Ophthalmology, University Hospital, LMU Munich, Munich, Germany.
Transl Vis Sci Technol. 2020 Jun 25;9(7):30. doi: 10.1167/tvst.9.7.30. eCollection 2020 Jun.
To evaluate the feasibility of corneal stromal filler injection to create bifocality to correct presbyopia by flattening the central posterior corneal surface and thus increase refractive power.
Femtosecond laser-assisted corneal stromal pockets of varying diameters close to the posterior corneal curvature were cut into rabbit eyes . Subsequently, hyaluronic acid was injected to flatten the central posterior curvature. Refractive parameters were determined using perioperatively acquired three-dimensional optical coherence tomography (OCT) scans. Using micrometer-resolution OCT, corneal endothelial cell morphology and density were evaluated.
Following filler injection into the corneal stromal pockets, a fair volume-dependent increase of central refractive power up to 4 diopters (dpt) was observed. Unremarkable refractive changes of the peripheral posterior (3 mm, 0.20 ± 0.11 dpt; 2 mm, 0.11 ± 0.10 dpt) and the anterior corneal curvature (3 mm, 0.20 ± 0.34 dpt; 2 mm, 0.33 ± 0.31 dpt) occurred. Only negligible changes in astigmatism were observed. Different sizes of optical zones could be established. Furthermore, no alterations of corneal endothelial morphology or endothelial cell density (2831 ± 356 cells/mm vs. 2734 ± 292 cells/mm; = 0.552) due to the adjacent laser treatment were observed.
The investigations proved the principle of injecting a filler material into femtosecond laser-created corneal stromal pockets close to the posterior corneal curvature as an efficacious, individually adjustable, and novel approach to correct presbyopia without ablating corneal tissue.
Due to the aging population worldwide, presbyopia is an increasing problem; thus, our study may encourage further exploration to extend the treatment spectrum of clinically used femtosecond laser systems to correct presbyopia.
评估通过使中央后角膜变平来增加屈光力，从而注射角膜基质填充物以产生双焦点来矫正老视的可行性。
在兔眼中制作接近后角膜曲率的不同直径的飞秒激光辅助角膜基质口袋，然后注入透明质酸以使中央后曲率变平。通过术中获得的三维光学相干断层扫描（OCT）扫描确定屈光参数。使用具有微米分辨率的 OCT 评估角膜内皮细胞形态和密度。
在向角膜基质口袋中填充填充物后，观察到中央屈光力随体积的适度增加，最高可达 4 屈光度（dpt）。周边后（3 毫米，0.20 ± 0.11 dpt；2 毫米，0.11 ± 0.10 dpt）和前角膜曲率（3 毫米，0.20 ± 0.34 dpt；2 毫米，0.33 ± 0.31 dpt）的屈光变化不明显。仅观察到散光的轻微变化。可以建立不同大小的光区。此外，由于相邻的激光治疗，未观察到角膜内皮形态或内皮细胞密度的变化（2831 ± 356 个细胞/平方毫米与 2734 ± 292 个细胞/平方毫米； = 0.552）。
这些研究证明了将填充材料注入飞秒激光在接近后角膜曲率处创建的角膜基质口袋中的原理，这是一种有效，可单独调节的新颖方法，可以在不消融角膜组织的情况下矫正老视。
张烁
