Effectiveness of Base in Prism for Presbyopes with Convergence Insufficiency.

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Effectiveness of Base in Prism for Presbyopes with Convergence Insufficiency. Optom Vis Sci. 2009 Jan 19; Authors: Teitelbaum B, Pang Y, Krall J PURPOSE.: Although the treatment of symptomatic convergence insufficiency (CI) with base-in (BI) prism in adults has a strong theoretical foundation, there have been very few studies addressing its efficacy. The purpose of this study was to investigate whether the application of BI prism, using a novel progressive addition lens design which incorporates BI prism in the near portion only, could help alleviate the symptoms in presbyopes with CI. METHODS.: A total of 29 symptomatic CI subjects aged 45 to 68 years were examined. All subjects took the CI Symptom Survey V-15 (CISS) and scored >/=16 points. Each subject was assigned two pairs of progressive addition glasses made by the same manufacturer in a randomized sequence, one with BI prism and one with the same lens prescription but no prism (placebo). Subjects wore each pair of glasses for 3 weeks and completed the CISS at the end of the 3rd week. Symptom level measured with CISS was the major outcome measure. RESULTS.: The mean (standard deviation) CISS score was 30.21 (9.30) at baseline and decreased to 13.38 (9.44) with the BI-prism glasses, vs. 23.62 (10.76) with the placebo glasses. There were significant differences between the baseline survey score and the score with the BI-prism glasses (p < 0.0001) and between the score with placebo glasses and the one with BI-prism glasses (p = 0.001). CONCLUSIONS.: The progressive addition glasses with BI-prism were found to be effective in alleviating symptoms of presbyopes with symptomatic CI. PMID: 19156012 [PubMed - as supplied by publisher]

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