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Retinal injury thresholds for 532, 578, and 630 nm lasers in connection to photodynamic therapy for choroidal neovascularization
Author(s) -
Chen Hongxia,
Yang Zaifu,
Zou Xianbiao,
Wang Jiarui,
Zhu Jianguo,
Gu Ying
Publication year - 2014
Publication title -
lasers in surgery and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 112
eISSN - 1096-9101
pISSN - 0196-8092
DOI - 10.1002/lsm.22196
Subject(s) - retinal , choroidal neovascularization , ophthalmology , photodynamic therapy , laser , medicine , retina , nuclear medicine , optics , materials science , chemistry , physics , organic chemistry
Abstract Background and Objectives The purpose of this study was to explore the retinal injury thresholds in rabbits and evaluate the influence of retinal pigmentation on threshold irradiance at laser wavelengths of 532, 578, and 630 nm which might be involved in hypocrellin B (HB) and hematoporphyrin monomethyl ether (HMME) photodynamic therapy (PDT) for choroidal neovascularization (CNV). Materials and Methods The eyes of pigmented and non‐pigmented rabbits were exposed to 532, 578, and 630 nm lasers coupled to a slit lamp biological microscope. The exposure duration was 100 seconds and the retinal spot size was 2 mm throughout the experiment. The minimum visible lesions were detected by funduscopy at 1 and 24 hours post exposure. Bliss probit analysis was performed to determine the ED 50 thresholds, fiducial limits and probit slope. Results In pigmented rabbits, the 24‐hour retinal threshold irradiances at 532, 578, and 630 nm were 1,003, 1,475, and 1,720 mW/cm 2 , respectively. In non‐pigmented rabbits, the 24‐hour threshold irradiances were 1,657, 1,865, and 15,360 mW/cm 2 , respectively. The ED 50 for 24‐hour observation differed very little from the ED 50 for 1‐hour observation. The non‐pigmented rabbits required a ninefold increase in threshold irradiance at 630 nm comparing to the pigmented rabbits. Conclusion This study will contribute to the knowledge base for the limits of laser irradiance in application of HB or HMME PDT for CNV. Lasers Surg. Med. 46:54–60, 2014. © 2013 Wiley Periodicals, Inc.