Relationship between Clinical History Method and Orbscan II for Measuring Corneal Power after LASIK.

Ku, Hee Chan; Cho, So Hyun; Kim, Hyo Jin; Kim, Jin Hyung; Joo, Choun Ki

Original Article

Journal of the Korean Ophthalmological Society 2005;46(4):581-588.
Published online April 30, 2005.

Relationship between Clinical History Method and Orbscan II for Measuring Corneal Power after LASIK.

Hee Chan Ku, So Hyun Cho, Hyo Jin Kim, Jin Hyung Kim, Choun Ki Joo

Department of Ophthalmology and Laboratory of Ophthalmology and Visual Science, The Catholic University of Korea, College of Medicine, Seoul, Korea. ckjoo@catholic.ac.kr

라식 수술 후 각막곡률계산법과 각막지형도에 의한 각막곡률의 상관성

구희찬,조소현,김효진,김진형,주천기

Department of Ophthalmology and Laboratory of Ophthalmology and Visual Science, The Catholic University of Korea, College of Medicine, Seoul, Korea.

Correspondence: Choun-Ki Joo, M.D., PhD.

Abstract

PURPOSE
To evaluate the relation between clinical history method and Orbscan II for corneal power measurement after laser in situ keratomileusis (LASIK). METHODS: A total of 77 consecutive eyes of 43 patients who were treated with LASIK for myopia were followed up for at least 6 months. Corneal power by clinical history methods (CK) was compared with 3.0 mm zones of simulated keratometry (Sim-K), with 0.5, 1.0, 1.5, 2.0 and 3.0 mm zones of axial power maps (AP) and with 2.0, 3.0, 3.5, 4.0 and 5.0 mm zones of total optical power maps (TOP). RESULTS: Sim-K and all AP-map zones using Orbscan II were significantly higher (P<.001) than the CK value, while all TOP-map zones were significantly lower (P<.001) than the CK value. Among them, 3.0 and 4.0 mm TOP-map zones showed the highest correlation with the corneal power by CK (r2=0.889, P<.001; r2=0.889, P<.001). The correlation was higher with 3.0 mm TOP-map zone (r2=0.800, P<.001) than with 4.0 mm TOP-map zone (r2=0.793, P<.001) in high myopia patients. CONCLUSIONS: Although 3.0 and 4.0 mm TOP-map zones of Orbscan II were correlated highly with the CK value, these correlations were relatively low in high myopia patients and 3.0 mm TOP-map zone was better correlated than 4.0 mm TOP-map zone in these patients.

Key Words: Clinical history method;Corneal power measurement;Orbscan II