Siamak Ansari-Shahrezaei1, Erdem Ergun, Michael Stur. 1. Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria. siamak.ansari-shahrezaei@meduniwien.ac.at
Abstract
BACKGROUND: To investigate the effect of refraction-corrected digital measurement software on photodynamic therapy (PDT) treatment spot size. METHODS: Experimental study using a calibrated Gullstrand-type model eye. The axial length of the model eye was set to different values, ranging from 20 to 31 mm, and the PDT treatment spot sizes obtained from refraction-corrected digital measurement software and manual measurement with a fixed-magnification factor, as well as four different indirect contact laser lenses, were calculated and compared for a treatment spot with a diameter of 4 mm. RESULTS: The maximum deviation from the treating laser spot was +39.6% under myopic and +17.4% under hyperopic conditions when the refraction-corrected digital measurement software was used. The maximum deviation was +14.2% under myopic and +13.3% under hyperopic conditions when the manual measurement with the fixed-magnification factor was used. CONCLUSIONS: The use of refraction-corrected digital measurement software produces a larger deviation from treating laser spot than the use of manual measurement with a fixed-magnification factor. Therefore, refraction-corrected digital measurement software might not be suitable for calculating the recommended PDT treatment spot size in eyes with high refractive errors.
BACKGROUND: To investigate the effect of refraction-corrected digital measurement software on photodynamic therapy (PDT) treatment spot size. METHODS: Experimental study using a calibrated Gullstrand-type model eye. The axial length of the model eye was set to different values, ranging from 20 to 31 mm, and the PDT treatment spot sizes obtained from refraction-corrected digital measurement software and manual measurement with a fixed-magnification factor, as well as four different indirect contact laser lenses, were calculated and compared for a treatment spot with a diameter of 4 mm. RESULTS: The maximum deviation from the treating laser spot was +39.6% under myopic and +17.4% under hyperopic conditions when the refraction-corrected digital measurement software was used. The maximum deviation was +14.2% under myopic and +13.3% under hyperopic conditions when the manual measurement with the fixed-magnification factor was used. CONCLUSIONS: The use of refraction-corrected digital measurement software produces a larger deviation from treating laser spot than the use of manual measurement with a fixed-magnification factor. Therefore, refraction-corrected digital measurement software might not be suitable for calculating the recommended PDT treatment spot size in eyes with high refractive errors.
Authors: Kevin J Blinder; Mark S Blumenkranz; Neil M Bressler; Susan B Bressler; Guy Donato; Hilel Lewis; Jennifer I Lim; Ugo Menchini; Joan W Miller; Jordi M Mones; Michael J Potter; Constantin Pournaras; Al Reaves; Philip Rosenfeld; Andrew P Schachat; Ursula Schmidt-Erfurth; Michel Sickenberg; Lawrence J Singerman; Jason S Slakter; H Andrew Strong; Gianni Virgili; George A Williams Journal: Ophthalmology Date: 2003-04 Impact factor: 12.079
Authors: Joachim Wachtlin; Tim Behme; Heinrich Heimann; Ulrich Kellner; Michael H Foerster Journal: Graefes Arch Clin Exp Ophthalmol Date: 2003-05-07 Impact factor: 3.117
Authors: E Smretschnig; S Hagen; C Glittenberg; R Ristl; I Krebs; S Binder; S Ansari-Shahrezaei Journal: Eye (Lond) Date: 2016-03-11 Impact factor: 3.775