Comparison of Corneal Thickness Measurements with Noncontact Specular Microscope and Ultrasonic Pachymeter. |
Yong Gi Jung, Jong Suk Song, Hyo Myung Kim, Hai Ryun Jung |
1Department of Ophthalmology, College of Medicine, Korea University, Seoul, Korea. hyomkim@ns.kumc.or.kr 2Department of Ophthalmology, Gachon Medical School Gil Medical Center, Incheon, Korea. |
비접촉 경면현미경과 초음파 각막두께측정기를 이용한 각막두께 측정의 비교 |
정용기 ( Yong Gi Jung ) , 송종석 ( Jong Suk Song ) , 김효명 ( Hyo Myung Kim ) , 정해륜 ( Hai Ryun Jung ) |
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Abstract |
PURPOSE To evaluate the corneal thickness values before and after refractive keratoplasty with the Topcon SP-2000 noncontact specular microscope(Topcon American Corp.) and the common standard ultrasonic pachymeter. METHODS: Corneal thickness was measured in 40 eyes of 20 patients, 5 times each before and after keratoplasty, with the Topcon SP-2000P and an ultrasonic pachymeter (DGH 1000, DGH Technology Inc.). The main outcome measures were accuracy and reproducibility as assessed with coefficient of variation (CV) of corneal thickness measurements. RESULTS: The reproducibility of corneal thickness measurements was better with the ultrasonic pachymeter (CV 0.36%) than with the Topcon SP-2000 (CV 1.23%). Mean corneal thickness measured by the Topcon SP-2000P before and after keratoplasty was significantly less than the mean values obtained with the ultrasonic pachymeter (14.4 micro meter; P<.0001, 5.6 micro meter; P<.01; respectively). Compared with theoretical ablated corneal thickness, ablated corneal thickness measured with the Topcon SP-2000P was significantly less (P<.01) than values obtained with the ultrasonic pachymeter (P=0.07) CONCLUSIONS: The noncontact Topcon specular microscope provides measurements of corneal thickness that are significantly less than those of the ultrasonic pachymeter, both before and after keratoplasty. These results indicate that these 2 techniques are not clinically comparable, thereby precluding interchangeable use of their data in planning or assessing keratoplasty. |
Key Words:
Corneal thickness;Keratoplasty;Noncontact specular microscope;Topcon SP-2000 |
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