Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics. University of Minho, Braga, Portugal.
Clinical & Experimental Optometry Research Lab (CEORLab), Center of Physics. University of Minho, Braga, Portugal.
Cont Lens Anterior Eye. 2019 Feb;42(1):28-35. doi: 10.1016/j.clae.2018.11.013. Epub 2018 Nov 28.
To compare three methods to measure central corneal clearance (CCC) during scleral lens wear: subjective (slit lamp), image processed (ImageJ) and with an optic biometer. The optic biometer technique was validated in comparison to an OCT in the first part of the study.
Twenty-two eyes (11 subjects) with healthy corneas were recruited. Three measures of OCT with scleral lens and ten measurements of axial length (AL) with IOLMaster with and without lens were performed. For the second part, 61 eyes (35 subjects) enrolled in a clinical study were selected. Measurements of CCC were done with IOLMaster, SlitLamp and ImageJ.
The measurements of CCC indirectly obtained with IOLMaster had a strong correlation with AS-OCT measurements (r = 0.981), showing a mean difference of 122.18 ± 46.05 μm (higher with IOLMaster). Regarding the second part, measurements of CCC were 238.66 ± 95.94 μm, 250.16 ± 124.31 μm and 263.15 ± 90.60 μm, for the IOLMaster, SlitLamp and ImageJ, respectively. The correlations were higher for ImageJ vs Subjective measure (r = 0.891) than for IOL vs Subjective (r = 0.748) and IOL vs ImageJ (r = 0.745). Analysis of differences and correlations between SlitLamp and ImageJ through time showed a mean difference of -32.28 ± 89.95 μm (r = 0.683) at V1month, 12.53 ± 59.46 μm (r = 0.850) at V6months and 11.57 ± 32.95 μm (r = 0.940) at V12months.
It is possible to measure CCC with IOLMaster, considering AL measured with and without lens and lens thickness. The three methods tested have good correspondence, showing that IOLMaster and ImageJ could be objective techniques to measure CCC. Also, it is possible to improve the agreement of subjective measures when compared to objective measures trough time.
比较三种方法来测量巩膜镜佩戴期间的中央角膜间隙（CCC）：主观（裂隙灯）、图像处理（ImageJ）和光学生物测量仪。在研究的第一部分，将光学生物测量仪技术与 OCT 进行了验证。
招募了 22 只眼睛（11 名受试者），这些眼睛的角膜健康。对带有巩膜镜的 OCT 进行了三次测量，并对带有和不带有镜片的 IOLMaster 进行了 10 次眼轴（AL）测量。在第二部分，从一项临床研究中选择了 61 只眼睛（35 名受试者）。使用 IOLMaster、裂隙灯和 ImageJ 进行 CCC 测量。
间接使用 IOLMaster 测量的 CCC 与 AS-OCT 测量值具有很强的相关性（r=0.981），平均差值为 122.18±46.05μm（IOLMaster 测量值较高）。关于第二部分，IOLMaster、裂隙灯和 ImageJ 分别测量的 CCC 为 238.66±95.94μm、250.16±124.31μm 和 263.15±90.60μm。ImageJ 与主观测量值的相关性高于 IOL vs 主观测量值（r=0.891），高于 IOL vs ImageJ（r=0.748）。通过时间分析裂隙灯和 ImageJ 之间的差异和相关性，在 V1 个月时，差异平均值为-32.28±89.95μm（r=0.683），在 V6 个月时为 12.53±59.46μm（r=0.850），在 V12 个月时为 11.57±32.95μm（r=0.940）。
可以使用 IOLMaster 测量 CCC，同时考虑有和没有镜片以及镜片厚度的 AL 测量值。三种测试方法具有良好的一致性，表明 IOLMaster 和 ImageJ 可以作为测量 CCC 的客观技术。此外，通过时间比较，主观测量值与客观测量值的一致性可以得到改善。
