Clinical Ophthalmology (Jul 2017)

Comparison of corneal power obtained from VERION image-guided surgery system and four other devices

  • Lin HY,
  • Chen HY,
  • Fam HB,
  • Chuang YJ,
  • Yeoh R,
  • Lin PJ

Journal volume & issue
Vol. Volume 11
pp. 1291 – 1299

Abstract

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Hung-Yuan Lin,1,* Hsin-Yang Chen,1,2,* Han Bor Fam,3 Ya-Jung Chuang,1 Ronald Yeoh,4 Pi-Jung Lin5 1Universal Eye Center, Zhongli Branch, Zhongli County, TaoYuan City, Taiwan, Republic of China; 2Ophthalmology Department, Ningbo First Hospital, Ningbo, Zhejiang Province, People’s Republic of China; 3Ophthalmology Department, Tan Tock Seng Hospital, Jalan Tan Tock Seng, 4Ophthalmology Department, Eye and Retina Surgeons, Camden Medical Centre, Singapore; 5Universal Eye Center, Xinnan Branch, Taipei City, Taiwan, Republic of China *These authors contributed equally to this work Purpose: To assess the corneal keratometric values obtained using the VERION image-guided surgery system and other devices.Methods: This study evaluated the right eyes of 115 cataract patients before intraocular lens (IOL) implantation through consecutive tests using 5 devices: VERION Reference Unit , Placido-based corneal topography (OPD-Scan III), monochromatic light-emitting diodes (LenStar LS900 and AL-Scan), and rotary prism technology (auto kerato-refractometer KR-8800). Analyzed parameters were corneal steep and flat keratometric values (Ks and Kf) and corneal astigmatism and axis. These parameters were evaluated using the one-sample two-tailed t-test and the 95% limits of agreement (95% LOAs) between the devices.Results: The mean corneal cylinder value measurements were -0.97±0.63 D, -0.88± 0.60 D, -0.90±0.69 D, -0.90±0.67 D, and -0.83±0.60 D with VERION, LenStar, AL-Scan (2.4 mm), OPD III, and KR-8800, respectively. Only KR-8800 showed a significant difference from VERION in the corneal cylinder value (P<0.05). The mean differences in the Kf and Ks of VERION compared to those of OPD III were 0.18±0.45 D and 0.17±0.38 D (P<0.05), respectively. The 95% LOAs of Bland–Altman analysis for the corneal astigmatism axis of the VERION with LenStar, AL-Scan (2.4 mm), OPD III, and KR-8800 were -26.25° to 58.71°, -20.61° to 47.44°, -25.03° to 58.98°, and -27.85° to 65.17°, respectively.Conclusion: None of the VERION parameters were significantly different from those of AL-Scan and LenStar. AL-Scan (2.4 mm zone) was especially similar to VERION. Wide LOAs are potential contributors to axis error in patients with toric IOL implants. Keywords: phacoemulsification, toric IOL, corneal astigmatism, surgical induced astigmatism, image-guided surgery system

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