목적: 각막굴절교정수술 후 인공수정체 결정시, Orbscan II 비디오각막경을 이용한 임상증례 3예를 보고하고자 한다. 증례요약: 굴절교정수술 전후의 각막곡률값과 굴절치를 알 수 없었던 3명 3안에서 Orbscan II의 mean, axial, tangential, optical power map에서 3, 4, 5, 6 mm의 각막곡률값을 구하고, SRK/T 공식으로 인공수정체 도수를 구하였다. 5 mm total axial power, 4 mm total optical power를 이용하여 도수를 구해 인공수정체를 삽입하였고, 3명 모두에서 1.5D 이내의 굴절치 차이를 보였다. 술 후 1개월째 굴절치와 목표 굴절치를 비교하였고, 술 후 굴절치를 통해 역계산 각막곡률값을 계산하여 Orbscan II의 각막곡률값과 비교하였다. 3, 4 mm total axial power, 3 mm total optical power와 역계산 각막곡률값이 차이가 적었다. 결론: 각막굴절교정수술 전후의 각막곡률값과 굴절치를 알 수 없는 경우 Orbscan II의 각막곡률값을 이용하여 인공수정체 도수를 계산하면 목표 굴절치에 근접할 것으로 기대할 수 있다.

Purpose: To report three cases of corneal power estimation for intraocular lens power calculation using Orbscan II videokeratography in eyes with previous corneal refractive surgeries. Case summary: In three eyes of three patients with previous corneal refractive surgeries, corneal power values were respectively measured at three, four, five, six mm-diameter zones of total mean, axial, tangential, and optical maps using Orbscan II videokeratography. Then, intraocular lens power values were calculated via the SRK/T formula. After cataract surgeries, back-calculated corneal power (BCK) values were estimated from post-phacoemulsification refraction data, and compared with those measured at three, four, five, six mm-diameter zones of each map in Orbscan II videokeratography. The postoperative refractive values after cataract surgeries were achieved within 1.5D of the target refraction in all eyes by using five mm total axial power and four mm total optical power for intraocular lens power calculation. Orbscan II parameters including three mm, four mm total axial power, and three mm total optical power were the least different from the BCK (0.69±0.49D, 1.08±0.54D, and 1.10±0.44D, respectively). Conclusions: If historical data are not available, Orbscan II videokeratography can be useful for estimating corneal power for intraocular lens power calculations in patients with previous corneal refractive surgeries.

Purpose: To report three cases of corneal power estimation for intraocular lens power calculation using Orbscan II videokeratography in eyes with previous corneal refractive surgeries. Case summary: In three eyes of three patients with previous corneal refractive surgeries, corneal power values were respectively measured at three, four, five, six mm-diameter zones of total mean, axial, tangential, and optical maps using Orbscan II videokeratography. Then, intraocular lens power values were calculated via the SRK/T formula. After cataract surgeries, back-calculated corneal power (BCK) values were estimated from post-phacoemulsification refraction data, and compared with those measured at three, four, five, six mm-diameter zones of each map in Orbscan II videokeratography. The postoperative refractive values after cataract surgeries were achieved within 1.5D of the target refraction in all eyes by using five mm total axial power and four mm total optical power for intraocular lens power calculation. Orbscan II parameters including three mm, four mm total axial power, and three mm total optical power were the least different from the BCK (0.69±0.49D, 1.08±0.54D, and 1.10±0.44D, respectively). Conclusions: If historical data are not available, Orbscan II videokeratography can be useful for estimating corneal power for intraocular lens power calculations in patients with previous corneal refractive surgeries.