Maeda N, Klyce S D, Smolek M K, Hamano H, Mitsunaga S, Watanabe K
Department of Ophthalmology, Osaka University Medical School, Suita, Japan.
Jpn J Ophthalmol. 1997 Jul-Aug;41(4):235-9. doi: 10.1016/s0021-5155(97)00048-8.
The greater utilization of soft contact lenses calls for the development of new and objective methods of evaluating the optical performance of the different lens types, in situ. We used videokeratography to examine the surface topography of soft contact lenses that had been worn for more than 1 year on 27 eyes of 23 patients, and compared the resulting color-coded maps and topographic indices as well as contact lens-corrected visual acuities, with those obtained with new replacement lenses on the same eyes. Visual inspection of the color-coded maps revealed differences in the surface characteristics of the used and new lenses. Comparison of quantitative indices including the SAI (Surface Asymmetry Index), IAI (Irregular Astigmatism Index), SRI (Surface Regularity Index), and SDP (Standard Deviation of Powers) showed that asymmetry, surface irregularity, potential visual acuity (derived from the SRI), and corneal power distribution were significantly poorer with the used lenses than with the new (P = 0.0001). The videokeratoscope is useful for evaluating the soft contact lens surface in situ, as an indicator of optical quality; it also permits the objective evaluation of lens cleaning techniques.
软性隐形眼镜使用的增加，需要开发新的、客观的方法来原位评估不同类型镜片的光学性能。我们使用角膜地形图仪对23例患者的27只眼睛上佩戴超过1年的软性隐形眼镜的表面形貌进行了检查，并将由此得到的彩色编码图、地形学指标以及隐形眼镜矫正视力，与同一只眼睛上佩戴新的更换镜片时所获得的结果进行了比较。对彩色编码图的目视检查揭示了使用过的镜片和新镜片在表面特征上的差异。包括SAI（表面不对称指数）、IAI（不规则散光指数）、SRI（表面规则性指数）和SDP（屈光度标准差）在内的定量指标比较显示，使用过的镜片在不对称性、表面不规则性、潜在视力（由SRI得出）和角膜屈光力分布方面明显比新镜片差（P = 0.0001）。角膜地形图仪可用于原位评估软性隐形眼镜表面，作为光学质量的指标；它还允许对镜片清洁技术进行客观评估。
