The impact of orthokeratology and soft lens wear on corneal immune cells and nerves in an adult population
UNSW Sydney, New South Wales, Australia
Understanding the immune response of the cornea during contact lens wear is important to minimise corneal inflammation and infection. Corneal immune response can be studied by examining corneal epithelial dendritic cells (CEDC). Compared to non-wearers, CEDC density is increased in soft contact lens wearers (SCL), suggesting an increased immune tone. Orthokeratology (OK) is increasingly used in myopia control but its impact on corneal immunology is unknown. This study compared immune tone of corneas during OK, SCL and no lens wear by investigating CEDC density and morphology. The relationship of CEDC with corneal nerve density was also examined. A retrospective analysis was conducted of in vivo confocal microscope (HRT-Rostock) images of 18 OK, 18 SCL (7 silicone hydrogel, 11 hydrogel) and 18 non-wearers with mean age of 27.6±8.0 years; 65% were female. CEDC density was counted manually and the highest-grade morphology was recorded by a masked observer at the central and mid-peripheral cornea (2.5mm temporal) using three novel scales based on CEDC cell body size, dendrite length and dendrite shape. Differences in corneal immune tone were evident in OK and SCL wear. The density and size of CEDC was reduced in OK but increased in SCL wear compared to non-wearers, suggesting possible suppression of the corneal immune tone in OK lens wear and requires further investigation. This study will not only provide fundamental information on the ocular immune response but will provide insights into methods of improving the safety of contact lens related myopia control treatment. Comparing the immune response of cornea in this young population to previously studies indicate that younger population have different response which may indicate that age effects ocular immune response during inflammation.