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Zachary Rishardson, Anastasios J Kanellopoulos, George Asimellis; The change of scotopic and photopic pupil shape and size, and its reference to the cornea apex in cataract surgery. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4842.
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© ARVO (1962-2015); The Authors (2016-present)
To implement digital analysis of pupil imaging (shape and size) in relation to cornea apex position and compare preoperative and postoperative data to measure the possible pupil shape and centration changes following cataract surgery.
35 consecutive cataract patients (70 eyes) were digitally imaged pre- and post-operatively by Placido Topography (Vario Topolyzer, WaveLight, Erlagen, Germany) providing pupil imaging and cornea apex identification. Digital analysis implemented on the images investigated the Cartesian coordinates (nasal - temporal being the horizontal, and superior-inferior the vertical axis) of the corneal apex (approximating the intersection of line of sight with the cornea) to the pupil geometric center (approximating the visual axis). The Cartesian changes of the differences were associated with postoperative pupil centroid shift.
The photopic pupil measurements indicated a pre-operative temporal location of 0.24 ± 0.15 (0.03 to 0.44) mm and a superior of 0.01±0.14 (-0.22 to +0.18) mm. Postoperatively, the pupil center appeared shifted temporally by 0.15 ± 0.12 (0.27 to -0.01) mm and superiorly by +0.06 ± 0.21 (-0.33 to 0.22) mm. The scotopic pupil measurements were preoperatively temporally by 0.28 ± 0.15 (0.41 to 0.03) mm, and inferiorly by 0.02 ± 0.20 (-0.24 to 0.29) mm. Postoperatively the pupil center was temporally by 0.20 ± 0.10 (0.04 to 0.28) mm and superiorly by 0.04 ± 0.19 (-0.26 to +0.27) mm.
Cataract extraction surgery appears to affect pupil centration. Specifically a more nasal (+0.10 mm) and more superior (0.05 mm) shift was recorded. These data may have clinical reference in targeted intraoperative IOL centration.
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