Moschos Marilita M, Nitoda Eirini, Georgoudis Panagiotis, Balidis Miltos, Karageorgiadis Eleftherios, Kozeis Nikos
Department of Ophthalmology, Medical School, National & Kapodistrian University of Athens, Greece.
Queen Victoria Hospital NHS Trust, East Grinstead, United Kingdom.
Open Ophthalmol J. 2017 Jul 31;11:241-251. doi: 10.2174/1874364101711010241. eCollection 2017.
Keratoconus is a chronic, bilateral, usuallly asymmetrical, non-inflammatory, ectatic disorder, being characterized by progressive steepening, thinning and apical scarring of the cornea. Initially, the patient is asymptomatic, but the visual acuity gradually decreases, resulting in significant vision loss due to the development of irregular astigmatism, myopia, corneal thinning and scarring. The classic treatment of visual rehabilitation in keratoconus is based on spectacles and contact lenses (CLs).
To summarize the types of CLs used in the treatment of keratoconus. This is literature review of several important published articles focusing on the visual rehabilitation in keratoconus with CLs.
Gas permeable (GP) CLs have been found to achieve better best corrected visual acuity than spectacles, eliminating 3rd-order coma root-mean-square (RMS) error, 3rd-order RMS, and higher-order RMS. However, they have implicated in reduction of corneal basal epithelial cell and anterior stromal keratocyte densities. Soft CLs seem to provide greater comfort and lower cost, but the low oxygen permeability (if the lens is not a silicone hydrogel), and the inability to mask moderate to severe irregular astigmatism are the main disadvantages of them. On the other hand, scleral CLs ensure stable platforms, which eliminate high-order aberrations and provide good centration and visual acuity. Their main disadvantages include the difficulties in application and removal of these lenses along with corneal flattening and swelling.
The modern hybrid CLs are indicated in cases of poor centration, poor stability or intolerance with GP lenses. Finally, piggyback CL systems effectively ameliorate visual acuity, but they have been related to corneal neovascularization and giant papillary conjunctivitis.
CLs seem to rehabilitate visual performance, diminishing the power of the cylinder and the high-order aberrations. The final choice of CLs is based on their special features, the subsequent corneal changes and the patient's needs.
圆锥角膜是一种慢性、双侧性、通常不对称的非炎症性扩张性疾病，其特征为角膜进行性变陡、变薄及顶端瘢痕形成。最初，患者无症状，但由于不规则散光、近视、角膜变薄和瘢痕形成，视力逐渐下降，导致严重视力丧失。圆锥角膜视觉康复的经典治疗方法基于眼镜和隐形眼镜（CLs）。
总结用于治疗圆锥角膜的隐形眼镜类型。这是一篇对几篇重要已发表文章的文献综述，重点关注使用隐形眼镜进行圆锥角膜视觉康复。
已发现透气性（GP）隐形眼镜比眼镜能获得更好的最佳矫正视力，可消除三阶彗差均方根（RMS）误差、三阶RMS及高阶RMS。然而，它们与角膜基底上皮细胞和前基质角膜细胞密度降低有关。软性隐形眼镜似乎能提供更大的舒适度和更低的成本，但低透氧性（如果镜片不是硅水凝胶）以及无法矫正中度至重度不规则散光，是其主要缺点。另一方面，巩膜隐形眼镜可确保稳定的平台，消除高阶像差并提供良好的定心和视力。其主要缺点包括佩戴和摘取这些镜片困难，以及角膜变平和肿胀。
现代混合型隐形眼镜适用于定心差、稳定性差或对GP镜片不耐受的情况。最后，叠戴式隐形眼镜系统能有效改善视力，但与角膜新生血管形成和巨大乳头性结膜炎有关。
隐形眼镜似乎能恢复视觉性能，降低柱镜度数和高阶像差。隐形眼镜的最终选择基于其特殊特性、随后角膜的变化以及患者的需求。
