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Preeji Sudharman Mandathara, Fiona Stapleton, Jim Kokkinakis, Mark D P Willcox; A pilot study of corneal sensitivity and its associations in keratoconus. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2896.
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© ARVO (1962-2015); The Authors (2016-present)
To examine changes in corneal sensitivity and its association with other clinical parameters in keratoconus.
24 keratoconus subjects aged 18-65 years were recruited. Ocular symptoms using validated questionnaires (ocular surface disease index and contact lens dry eye questionnaire 8), corneal topography, tear osmolarity, tear meniscus height measurement, tear volume, ocular surface staining with fluorescein and lissamine green dye, corneal sensitivity threshold using Cochet-Bonnet aesthesiometer and corneal nerve mapping using HRT II confocal microscopy were obtained. Correlations were sought by determining either the Spearman’s or Pearson’s coefficient. Partial correlation was performed to control the effect of confounding factors.
Based on the maximum simulated keratometry (K max) reading, subjects were graded as having mild (N=11; K max ≤52D) or severe (N=13; K max >52D) keratoconus. Only data from the most severe eye of each subject were included in the analyses. Central corneal sensitivity was lower (i.e. increased corneal sensitivity threshold) in the severe keratoconus group compared to the mild keratoconus group (Median, range: 1.09, 0.42-19.66 vs 0.51, 0.39-3.74 g/mm2, p=0.035). In bivariate correlations, decreased corneal sensitivity in keratoconus was associated with severity (ρ = 0.43; p=0.032), lower central nerve fibre density (r=-0.68, p=0.014), contact lens wear (ρ=0.44; p= 0.025), and contact lens tolerance (ρ=0.455; p=0.033), and the age of the patient (r=0.414; p=0.036) and duration of the disease (r=0.467; p=0.016). There was no association between corneal sensitivity and symptom scores and the tear variables of osmolarity, volume or meniscus height. After adjusting for contact lens wear, there was no association between corneal sensitivity and severity or nerve fibre density, but there was a trend (p<0.1) where age and duration of the disease were associated with decreased corneal sensitivity. Contact lens intolerants had a higher corneal sensitivity compared to tolerant people. (Median, range: 0.56, 0.39-2.17 vs 1.51, 0.39-19.66 g/mm2, p=0.026).
Decreased corneal sensitivity was associated with age and duration of disease. Reduced tolerance to contact lenses in keratoconus was associated with increased corneal sensitivity.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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