Contemporary soft contact lenses do not affect mechanical sensitivity of the cornea, whereas conjunctival sensitivity is increased compared with nonwearers. Orthokeratology lens wear, however, reduces corneal sensitivity. The effects of contact lenses on lid margin sensitivity are unclear, and the link between ocular surface sensitivity and discomfort requires further exploration.
Although up to 50% of contact lens wearers experience discomfort with varying severity, impact, and frequency, the relationship between ocular surface sensitivity and ocular surface discomfort experienced during contact lens wear is unclear. The purpose of this review is to examine and summarize the current evidence for the impact of both historical and contemporary contact lens wear on ocular surface sensitivity, the etiology of changes in ocular surface sensitivity, contact lens wear–related factors associated with changes in ocular surface sensitivity, and the relationship between sensitivity and discomfort. Despite minimal effects on mechanical corneal sensitivity with contemporary soft contact lens wear, orthokeratology reduces corneal sensitivity through pressure-related effects. This review addresses the relevance of conjunctival and potentially lid margin sensitivity in tolerance and discomfort with contemporary lens wear and the impact of instrument and stimulus characteristics. Less invasive techniques particularly for lid margin sensitivity measurements are required. Given the potential interactions between a contact lens and the varied types of ocular surface nociceptors, instruments that allow for exploration of cold and chemical sensitivity particularly may better allow the effects of lens wear to be elucidated compared with those that explore high-threshold mechanical sensitivity alone. A better understanding of the relationships between lens wear and ocular surface sensitivity may result in improved management of contact lens discomfort.
1School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia
2Center for Translational Ocular Immunology, Tufts Medical Center, Boston, Massachusetts
Submitted: August 27, 2018
Accepted: July 21, 2019
Funding/Support: None of the authors have reported funding/support.
Conflict of Interest Disclosure: None of the authors have reported a financial conflict of interest in connection with this review article.
Author Contributions: Conceptualization: FS, BG; Investigation: FS, CC; Writing – Original Draft: FS, BG; Writing – Review & Editing: FS, CC, BG.