Comparison of Axial Length and Postoperative Refraction between Applanation Ultrasonography and Low-coherence Reflectometry. |
Yoon Pyo Lee, Young Joo Shin, Kayoung Yi |
Department of Ophthalmology, Kangnam Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Korea. kayoungyi@yahoo.co.kr |
접촉식 초음파와 저간섭성 반사계 간의 안축장 및 백내장수술 후 굴절력의 비교 |
이윤표⋅신영주⋅이가영 |
한림대학교 의과대학 강남성심병원 안과학교실 |
Correspondence:
Kayoung Yi, Email: kayoungyi@yahoo.co.kr |
Received: 14 February 2018 • Revised: 9 May 2018 • Accepted: 26 June 2018 |
Abstract |
PURPOSE To compare axial length applanation ultrasonography (A-scan) (CineScan B-Scan; Quantel Medical, Bozeman, MT, USA) and low-coherence reflectometry (Lenstar LS900®; Haag-Streit, Bern, Switzerland), the accuracy of the predictive postoperative refraction of both instruments, and the intraocular lens (IOL) calculators. METHODS: A total of 250 eyes of 191 patients who received cataract surgery were included in the study. The axial length was measured by the A-scan and Lenstar LS900®. The SRK-2, SRK/T, and Olsen formulas were used to calculate the IOL power, and the difference between the predictive and actual postoperative refractions after 6 weeks and the probability that they were within 0.25 diopters (D) and 0.5 D were compared. RESULTS: The mean axial lengths measured by the A-scan and Lenstar LS900® were 23.42 ± 0.94 mm and 23.55 ± 0.95 mm, respectively, which showed a statistically significant difference (paired t-test, p = 0.000). When comparing the difference between the predictive and actual postoperative refractions, the results of the A-scan using the SRK-2 and SRK/T formulas were significant toward the hyperopia, and the results of the Lenstar LS900® using the SRK-2, SRK/T, and Olsen formulas were significant toward the myopia (paired t-test, p = 0.001 and p < 0.001, respectively). When comparing the mean absolute difference between the two refractions and the probability that they were within 0.25 D and 0.5 D, the Lenstar LS900® using the Olsen formula significantly showed the highest accuracy (McNemar test, p = 0.045 and p = 0.002; p = 0.010 and p = 0.002, respectively). CONCLUSIONS: The A-scan using the SRK-2 and SRK/T formulas showed that the actual postoperative refraction was more hyperopic than the predicted refraction, whereas the Lenstar LS900® resulted in more myopic findings. The accuracy of predictive postoperative refraction was highest with the Lenstar LS900® using the Olsen formula. |
Key Words:
Applanation ultrasonography;Axial length;Cataract surgery;Low-coherence reflectometry;Postoperative refraction |
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