Short-Term Effects of Overnight Orthokeratology on Corneal Sub-basal Nerve Plexus Morphology and Corneal Sensitivity

Abstract

Objective: To assess the effects of a short period of orthokeratology (OK) on corneal subbasal nerve plexus (SBNP) morphology and corneal sensitivity. Methods: Measurements were made in 56 right eyes of 56 subjects with low-to-moderate myopia who wore 2 OK lens designs (Group CRT: HDS 100 Paragon CRT, n¼35; Group SF: Seefree; n¼21) for a period of 1 month and in 15 right eyes of noncontact lens wearers as controls. The variables determined in each participant were corneal sensitivity using a Cochet-Bonnet esthesiometer and 12 SBNP variables determined on laser scanning confocal microscopy images using 3 different software packages. Correlation between SBNP architecture and corneal sensitivity was also examined. Results: Few changes were observed over the 1-month period in the variables examined in the OK treatment and control groups. However, significant reductions were detected over time in the number of nerves in the central cornea in the groups CRT (P¼0.029) and SF (P¼0.043) and in central corneal sensitivity in CRT (P¼0.047) along with significant increases in central and midperipheral corneal Langerhans cell counts in SF (P¼0.001 and 0.048, respectively). Conclusions: This study provides useful data to better understand the anatomical changes induced by OK in corneal SBNP. The different response observed to the 2 OK lens designs requires further investigation.

Long-Term Impacts of Orthokeratology Treatment on Sub-Basal Nerve Plexus and Corneal Sensitivity Responses and Their Reversibility

“…Using this technology, it has being possible to assess these changes in the corneas of healthy individuals 10 , soft contact lens wearers 7,8 , subjects undergoing corneal surgery 12,13 , patients with a systemic diseass 14,15 and those undergoing overnight orthokeratology (OK) treatment 9,16,17 .…”

“…SBNP nerve redistribution has been linked to increased levels of pro-inflammatory molecules 22 . Consequently, and bearing in mind that inflammation due to the use of contact lenses induces the migration of Langerhans cells (LC) to the cornea 23,24 , we recently performed a study 17 in which it was observed that the use of OK lenses over a short period increases LC density in the cornea. However, little is still known about the course of these changes in the longer term and their possible recovery after interrupting OK lens wear.…”

“…The reversibility of these responses after discontinuing treatment was also assessed. Based on the recent finding of different short term responses to different OK lenses 17 , two different OK lens designs were fitted in our participants. SBNP thickness changes were also examined.…”

The corneal nerve density in the sub‐basal plexus decreases with increasing myopia: a pilot study

“…It is well known that lasik refractive surgery in myopia alters the nerve plexus by reducing its density over a period of time . New information also suggests orthokeratology can cause changes to the density of the nerve bed . Some groups have documented that density decreases with age .…”

“…3 New information also suggests orthokeratology can cause changes to the density of the nerve bed. 4 Some groups have documented that density decreases with age. [5][6][7][8] To our knowledge, no research groups thus far have examined changes in nerve density specifically for patients of different refractive errors.…”