Changes in Corneal Dendritic Cell and Sub-basal Nerve in Long-Term Contact Lens Wearers With Dry Eye

Abstract

Objectives: To evaluate the changes of corneal sub-basal nerve (SBN) and dendritic cell (DC) in contact lens (CL) wearers with mild dry eye and their potential relationship. Methods: Twenty mild dry eye volunteers who had never worn CLs were recruited for long-term CL wearing. Each subject underwent ocular surface evaluations at baseline and at 1, 4, 12, and 24 weeks, including Ocular Surface Disease Index (OSDI) questionnaire, tear film break-up time (TBUT), and Schirmer I test. In vivo confocal microscopy was used to examine the density, area, number of dendrites, total dendritic length of DC, and SBN densities in central and peripheral corneas. Only right eyes were included. Results: The DCs were activated and peaked at week 4 after wearing CLs. The peripheral DC density increased beginning the first week, whereas the central ones increased by week 4. After 4 weeks, both began to decrease, but still higher than baseline at week 24. The central and peripheral SBN densities decreased. However, the peripheral SBN tended to increase beginning at week 12. In early period, SBN was negatively correlated with DC parameters. After 4 weeks, the correlation changed to be positive. The OSDI increased, whereas the Schirmer I test and TBUT showed no significant change. Conclusions: After wearing CLs, corneal DC were activated and increased, indicating ocular surface inflammation and decreased after week 4. In the early period, increases in DC may lead to decreases in SBN. Upon decrease of DC, the SBN may regenerate.

Characteristics of Corneal Subbasal Nerves in Different Age Groups: An in vivo Confocal Microscopic Analysis

“… 4 Other etiologies of NK can be attributed to a direct corneal nerve injury (such as a trauma or burn), a severe corneal infection, keratorefractive surgery, and major corneal surgery including transplantation. 3 Moreover, chronic-repetitive corneal inflammation arising from contact lens use, recurrent corneal erosion, and dry eye 5 , 6 also impair the corneal subbasal nerves and eventually result in NK.…”

BCLA CLEAR - Effect of contact lens materials and designs on the anatomy and physiology of the eye

“…In contrast, another report found that CEDC density was not significantly higher than baseline until 4 weeks wear of hydrogel lenses and had not returned to baseline by 6 months [347]. Only two studies have quantified the distribution of CEDC away from the corneal centre.…”

“…in vivo confocal microscopy investigations have shown elevated CEDC density in the central cornea in soft contact lens wearers [192,193,[344][345][346][347], suggesting these cells migrate into the centre in response to an inflammatory stimulus, perhaps due to the presence of the contact lens, as has been shown in animal models of lens wear [348,349]. A summary of studies which have to date examined the effects of contact lens wear on corneal dendritic cell density presented in Table 2 illustrates much variability in cell numbers reported by different investigators who may have used differing methodologies and criteria.…”

“…Only two studies have quantified the distribution of CEDC away from the corneal centre. One report showed an increased density of CEDC in the peripheral cornea after 1 week of reusable hydrogel lenses, which had not returned to baseline at 6 months [347]. Another report showed CEDC density in the mid-peripheral cornea to be increased in lens wearers [190].…”

On the Keratoconjunctivitis Sicca

“…Therefore, the occurrence of KCS is obviously related to the length of wearing contact lenses. Wearing contact lenses can impair the growth and development of sensory nerves in the corners and conjunctiva, resulting in decreased perception of the corners and conjunctiva, reduced blinking, and tear film metabolic dysfunction, which ultimately leads to the occurrence of KCS (18,19).…”