Article: Visual symptoms and retinal straylight after laser peripheral iridotomy: the Zhongshan angle-closure prevention trial

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TitleVisual symptoms and retinal straylight after laser peripheral iridotomy: the Zhongshan angle-closure prevention trial
AuthorsCongdon, N3
Yan, X3
Friedman, DS4
Foster, PJ5
van den Berg, TJTP1
Peng, M4
Gangwani, R2
He, M3
Issue Date2012
PublisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/ophtha
CitationOphthalmology, 2012, v. 119 n. 7, p. 1375-1382 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.ophtha.2012.01.015
AbstractOBJECTIVE: To assess the impact of laser peripheral iridotomy (LPI) on forward-scatter of light and subjective visual symptoms and to identify LPI parameters influencing these phenomena. DESIGN: Cohort study derived from a randomized trial, using an external control group. PARTICIPANTS: Chinese subjects initially aged 50 or older and 70 years or younger with bilateral narrow angles undergoing LPI in 1 eye selected at random, and age- and gender-matched controls. METHODS: Eighteen months after laser, LPI-treated subjects underwent digital iris photography and photogrammetry to characterize the size and location of the LPI, Lens Opacity Classification System III cataract grading, and measurement of retinal straylight (C-Quant; OCULUS, Wetzlar, Germany) in the treated and untreated eyes and completed a visual symptoms questionnaire. Controls answered the questionnaire and underwent straylight measurement and (in a random one-sixth sample) cataract grading. MAIN OUTCOME MEASURES: Retinal straylight levels and subjective visual symptoms. RESULTS: Among 230 LPI-treated subjects (121 [58.8%] with LPI totally covered by the lid, 43 [19.8%] with LPI partly covered by the lid, 53 [24.4%] with LPI uncovered by the lid), 217 (94.3%) completed all testing, as did 250 (93.3%) of 268 controls. Age, gender, and prevalence of visual symptoms did not differ between treated subjects and controls, although nuclear (P<0.01) and cortical (P = 0.03) cataract were less common among controls. Neither presenting visual acuity nor straylight score differed between the treated and untreated eyes among all treated persons, nor among those (n = 96) with LPI partially or totally uncovered. Prevalence of subjective glare did not differ significantly between participants with totally covered LPI (6.61%; 95% confidence interval [CI], 3.39%-12.5%), partially covered LPI (11.6%; 95% CI, 5.07%-24.5%), or totally uncovered LPI (9.43%; 95% CI, 4.10%-10.3%). In regression models, only worse cortical cataract grade (P = 0.01) was associated significantly with straylight score, and no predictors were associated with subjective glare. None of the LPI size or location parameters were associated with straylight or subjective symptoms. CONCLUSIONS: These results suggests that LPI is safe regarding measures of straylight and visual symptoms. This randomized design provides strong evidence that treatment programs for narrow angles would be unlikely to result in important medium-term visual disability.
ISSN0161-6420
2011 Impact Factor: 5.454
2011 SCImago Journal Rankings: 0.392
DOIhttp://dx.doi.org/10.1016/j.ophtha.2012.01.015
DC Field
Value
dc.contributor.authorCongdon, N
dc.contributor.authorYan, X
dc.contributor.authorFriedman, DS
dc.contributor.authorFoster, PJ
dc.contributor.authorvan den Berg, TJTP
dc.contributor.authorPeng, M
dc.contributor.authorGangwani, R
dc.contributor.authorHe, M
dc.date.accessioned2012-10-18T09:00:35Z
dc.date.available2012-10-18T09:00:35Z
dc.date.issued2012
dc.description.abstractOBJECTIVE: To assess the impact of laser peripheral iridotomy (LPI) on forward-scatter of light and subjective visual symptoms and to identify LPI parameters influencing these phenomena. DESIGN: Cohort study derived from a randomized trial, using an external control group. PARTICIPANTS: Chinese subjects initially aged 50 or older and 70 years or younger with bilateral narrow angles undergoing LPI in 1 eye selected at random, and age- and gender-matched controls. METHODS: Eighteen months after laser, LPI-treated subjects underwent digital iris photography and photogrammetry to characterize the size and location of the LPI, Lens Opacity Classification System III cataract grading, and measurement of retinal straylight (C-Quant; OCULUS, Wetzlar, Germany) in the treated and untreated eyes and completed a visual symptoms questionnaire. Controls answered the questionnaire and underwent straylight measurement and (in a random one-sixth sample) cataract grading. MAIN OUTCOME MEASURES: Retinal straylight levels and subjective visual symptoms. RESULTS: Among 230 LPI-treated subjects (121 [58.8%] with LPI totally covered by the lid, 43 [19.8%] with LPI partly covered by the lid, 53 [24.4%] with LPI uncovered by the lid), 217 (94.3%) completed all testing, as did 250 (93.3%) of 268 controls. Age, gender, and prevalence of visual symptoms did not differ between treated subjects and controls, although nuclear (P<0.01) and cortical (P = 0.03) cataract were less common among controls. Neither presenting visual acuity nor straylight score differed between the treated and untreated eyes among all treated persons, nor among those (n = 96) with LPI partially or totally uncovered. Prevalence of subjective glare did not differ significantly between participants with totally covered LPI (6.61%; 95% confidence interval [CI], 3.39%-12.5%), partially covered LPI (11.6%; 95% CI, 5.07%-24.5%), or totally uncovered LPI (9.43%; 95% CI, 4.10%-10.3%). In regression models, only worse cortical cataract grade (P = 0.01) was associated significantly with straylight score, and no predictors were associated with subjective glare. None of the LPI size or location parameters were associated with straylight or subjective symptoms. CONCLUSIONS: These results suggests that LPI is safe regarding measures of straylight and visual symptoms. This randomized design provides strong evidence that treatment programs for narrow angles would be unlikely to result in important medium-term visual disability.
dc.description.natureLink_to_subscribed_fulltext
dc.identifier.citationOphthalmology, 2012, v. 119 n. 7, p. 1375-1382 [How to Cite?]
DOI: http://dx.doi.org/10.1016/j.ophtha.2012.01.015
dc.identifier.citeulike10472646
dc.identifier.doihttp://dx.doi.org/10.1016/j.ophtha.2012.01.015
dc.identifier.epage1382
dc.identifier.hkuros212130
dc.identifier.issn0161-6420
2011 Impact Factor: 5.454
2011 SCImago Journal Rankings: 0.392
dc.identifier.issue7
dc.identifier.pmid22424576
dc.identifier.scopuseid_2-s2.0-84863328137
dc.identifier.spage1375
dc.identifier.urihttp://hdl.handle.net/10722/169511
dc.identifier.volume119
dc.languageeng
dc.publisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/ophtha
dc.publisher.placeUnited States
dc.relation.ispartofOphthalmology
dc.subject.meshGlaucoma, Angle-Closure - prevention and control
dc.subject.meshIridectomy
dc.subject.meshLaser Therapy
dc.subject.meshRetina - radiation effects
dc.subject.meshRetinal Diseases - etiology
dc.titleVisual symptoms and retinal straylight after laser peripheral iridotomy: the Zhongshan angle-closure prevention trial
dc.typeArticle
Author Affiliations
  1. Netherlands Institute for Neuroscience NIN - KNAW
  2. The University of Hong Kong
  3. Zhongshan Ophthalmic Center
  4. The Wilmer Eye Institute at Johns Hopkins
  5. UCL Institute of Ophthalmology