Scleral contact lens thickness profiles: The relationship between average and centre lens thickness

Stephen J. Vincent; David Alonso-Caneiro; Henry Kricancic; Michael J. Collins

doi:10.1016/j.clae.2018.03.002

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Scleral contact lens thickness profiles: The relationship between average and centre lens thickness

Journal article

Peer reviewed

Scleral contact lens thickness profiles: The relationship between average and centre lens thickness

Stephen J. Vincent, David Alonso-Caneiro, Henry Kricancic and Michael J. Collins

Contact Lens & Anterior Eye, Vol.42(1), pp.55-62

2019

DOI: https://doi.org/10.1016/j.clae.2018.03.002

PMID: 29555408

Abstract

scleral contact lens

scleral lens thickness

OCT imaging

oxygen transmissibility

Purpose: To develop a methodology to reliably determine the thickness profile of scleral contact lenses and examine the relationship between the centre and average lens thickness for a range of lens designs and back vertex powers. Methods: High-resolution images of 37 scleral trial lenses (Epicon LC, Rose K2 XL and ICD 16.5) were captured using an optical coherence tomographer, and their thickness profiles were generated after correcting for known measurement artefacts. Centre lens thickness values were compared with manual lens gauge measurements, and repeatability was assessed by comparing average thickness values derived from orthogonal meridians of each lens. Results: The imaging technique displayed a high level of agreement with a manual lens gauge for centre thickness measurements; mean difference 5 +/- 9 mu m (95% LoA -14 to + 23 mu m), and a very high level of repeatability; mean difference between orthogonal meridians 1 +/- 3 mu m (95% LoA -6 to +8 mu m). Lens thick-ness profiles varied between lens designs, with distance from the lens centre, and with back vertex power. Increasing back vertex powers resulted in a significant over or underestimation (up to 33% for high minus powers) of the average lens thickness based on the centre lens thickness. Conclusions: The thickness of scleral contact lenses varies with distance from the lens centre and the back vertex power. The average lens thickness value derived from the entire lens provides a more appropriate representation of the true lens thickness and should be used in the calculation of scleral lens oxygen transmissibility.

Details

Title: Scleral contact lens thickness profiles: The relationship between average and centre lens thickness
Authors: Stephen J. Vincent (Corresponding Author) - Queensland University of Technology
David Alonso-Caneiro (Author) - Queensland University of Technology
Henry Kricancic (Author) - Queensland University of Technology
Michael J. Collins (Author) - Queensland University of Technology
Publication details: Contact Lens & Anterior Eye, Vol.42(1), pp.55-62
Publisher: Elsevier BV
DOI: 10.1016/j.clae.2018.03.002
ISSN: 1476-5411
PMID: 29555408
Organisation Unit: School of Science, Technology and Engineering
Language: English
Record Identifier: 99973594102621
Output Type: Journal article