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Preeji Sudharman, Fiona Stapleton, Jim Kokkinakis, Mark Willcox; Factors associated with contact lens intolerance in keratoconus. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3924.
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© ARVO (1962-2015); The Authors (2016-present)
Contact lens intolerance in keratoconus is a significant factor that can lead to corneal transplantation. Identifying the factors associated with contact lens intolerance is important for the development of strategies to improve tolerance and thereby to reduce or delay the need for corneal transplantation. This study evaluated ocular surface factors associated with contact lens intolerance in keratoconus.
Keratoconus subjects aged between 18-65 years, who had tried contact lenses for vision correction, were included in this cross sectional study. The variables assessed include demographic data, corneal topography, ocular symptoms, ocular surface disease index, pain sensitivity, tear variables including osmolarity, tear meniscus height and tear volume, ocular surface staining and corneal sensitivity threshold using Cochet-Bonnet aesthesiometer. Contact lens intolerance was defined as an inability to wear contact lenses for more than 4 hours continuously due to discomfort. The association between contact lens tolerance and other clinical variables was studied using Spearman’s correlation. Statistical significance was set at p<0.05.
Twenty eight keratoconus subjects were included in the study. The mean age was 44 ± 12 years, 75% of them were males, and 22 participants were wearing contact lenses at the time of the study. Contact lens intolerance was reported by 39% of subjects. A significant association was found between contact lens tolerance and reduced corneal sensitivity (rho=0.482, p=0.011). No significant associations were found between contact lens tolerance and dry eye symptoms, OSDI index, tear osmolarity, tear meniscus height, tear volume or corneal staining (Rho and p-values:-0.239,0.240; -0.079, 0.700; -0.048, 0.818; 0.141, 0.484; 0.135, 0.501; 0.012,0.951). Post hoc power calculation revealed the study had 80% power to detect associations with an effect size 0.48 or greater at an alpha error of 5%.
Central corneal sensitivity was the only factor associated with contact lens tolerance in keratoconus. Contact lens designs that have least interaction with the corneal surface such as scleral or mini-scleral designs may be helpful in contact lens intolerant keratoconus subjects.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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