Optimal time following fluorescein instillation to evaluate rigid gas permeable contact lens fit


PURPOSE: To examine the optimum time at which fluorescein patterns of gas permeable lenses (GPs) should be evaluated. METHODS: Aligned, 0.2mm steep and 0.2mm flat GPs were fitted to 17 patients (aged 20.6±1.1 years, 10 male). Fluorescein was applied to their upper temporal bulbar conjunctiva with a moistened fluorescein strip. Digital slit lamp images (CSO, Italy) at 10× magnification of the fluorescein pattern viewed with blue light through a yellow filter were captured every 15s. Fluorescein intensity in central, mid peripheral and edge regions of the superior, inferior, temporal and nasal quadrants of the lens were graded subjectively using a +2 to -2 scale and using ImageJ software on the simultaneously captured images. RESULTS: Subjectively graded and objectively image analysed fluorescein intensity changed with time (p<0.001), lens region (centre, mid-periphery and edge: p<0.05) and there was interaction between lens region with lens fit (p<0.001). For edge band width, there was a significant effect of time (F=118.503, p<0.001) and lens fit (F=5.1249, p=0.012). The expected alignment, flat and steep fitting patterns could be seen from approximately after 30 to 180s subjectively and 15 to 105s in captured images. CONCLUSION: Although the stability of fluorescein intensity can start to decline in as little as 45s post fluorescein instillation, the diagnostic pattern of alignment, steep or flat fit is seen in each meridian by subjective observation from about 30s to 3min indicating this is the most appropriate time window to evaluate GP lenses in clinical practice.

Publication DOI: https://doi.org/10.1016/j.clae.2014.11.203
Divisions: College of Health & Life Sciences > School of Optometry > Optometry
College of Health & Life Sciences > School of Optometry > Optometry & Vision Science Research Group (OVSRG)
College of Health & Life Sciences
College of Health & Life Sciences > School of Optometry > Vision, Hearing and Language
Additional Information: NOTICE: this is the author’s version of a work that was accepted for publication in Contact lens and anterior eye. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Wolffsohn, JS, Tharoo, A & Lakhlani, N, 'Optimal time following fluorescein instillation to evaluate rigid gas permeable contact lens fit' Contact lens and anterior eye, vol 38, no. 2 (2015) DOI: http://dx.doi.org/10.1016/j.clae.2014.11.203
Uncontrolled Keywords: rigid gas permeable,fit evaluation,fluorescein,gas permeable,Ophthalmology,Optometry
Publication ISSN: 1476-5411
Last Modified: 17 Jul 2024 07:04
Date Deposited: 16 Apr 2015 13:55
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
PURE Output Type: Article
Published Date: 2015-04
Published Online Date: 2014-12-24
Authors: Wolffsohn, James S. (ORCID Profile 0000-0003-4673-8927)
Tharoo, Ali
Lakhlani, Nikita



Version: Accepted Version

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