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Edward Lum, Alan Ng, Luigina Sorbara, Paul J Murphy; Impact of scleral lens wear on ocular sensitivity, nerve fiber density and Langerhans cell density in keratoconus. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1764.
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© ARVO (1962-2015); The Authors (2016-present)
This study investigated changes in corneal innervation during scleral lens wear in a keratoconic population, over a one-month lens wear period. The change in density of Langerhans cells was also investigated as a marker of corneal inflammation.
Seven keratoconic participants (mean age:34yrs, range:20-56yrs, 5M/2F) with no previous rigid gas-permeable lens wear experience were fitted with scleral contact lenses (ICD™ Flexfit, 14.8 mm dia., Paragon HDS100) according to manufacturer’s guidelines (Precision Technology Services). Study parameters were collected in each eye at baseline (BL) and following 1 month (M1) of lens wear. Ocular surface sensitivity was assessed at the central cornea using both the Cochet-Bonnet aesthesiometer (CBA) and Non-Contact Corneal Aesthesiometer (NCCA), and additionally the temporal limbus using the NCCA. Central corneal nerve fiber (NFD) and Langerhans cell (LCD) density were assessed by sampling the sub-basal nerve plexus using the Heidelberg Retinal Tomographer with Rostock Corneal Module, and analysed using automated software (ACCMetrics) or manually counted by a masked investigator. A mixed random effects model was used to assess the effect of ocular location and visit. A p-value <0.05 denoted statistical significance.
Corneal sensation threshold appeared to increase in the central (BL: 0.60±0.48; M1: 0.80±0.53 mBars) but not limbal (BL: 0.40±0.26; M1: 0.46±0.28 mBars) locations using the NCCA. This change did not reach statistical significance (p=0.087). There was no significant change in the central cornea using the CBA (BL: 2.0±1.6; M1: 2.2±1.5 g/mm2, p=0.66). No significant changes were observed in the central NFD (BL: 12.5±3.9; M1: 12.7±4.8 mm/mm2, p=0.076) or LCD (BL: 15±21; M1: 13±16 cells/mm2, p=0.69).
Short-term scleral lens wear in keratoconic eyes does not alter ocular surface sensitivity to non-contact (thermally-cool) or mechanical (touch) stimuli. However, change in central corneal sensitivity to thermally-cool stimulus suggests a trend towards desensitization. Lens wear did not alter nerve morphology or Langerhans cell density, at least after 1 month of wear.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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