Abstract
Purpose :
To investigate morphological changes in the bulbar conjunctiva after mini-scleral contact lens (MScCL) wear using in vivo confocal microscopy (IVCM), and to explore the relationship between conjunctival changes at the cellular level and MScCL settling.
Methods :
12 healthy subjects (age range 22-24 years; 5M, 7F) were fitted with KATT MScCL (16.5 mm diameter; Capricornia Contact Lens, Australia) on one eye only. Morphological changes in the superior and temporal regions of the bulbar conjunctiva after 2 hours of MScCL wear were quantified using the IVCM (Heidelberg Retinal Tomographer, Germany). The depth of the tear reservoir (central corneal clearance, CCC) between the cornea and lens was measured using an anterior segment OCT (Tomey CASIA, Japan) after 10 minutes and 2 hours of lens wear. Paired t-tests or Wilcoxon signed rank tests were used to analyse the changes in study variables with MScCL wear.
Results :
The mean change in CCC between 10 minutes and 2 hours of MScCL wear was 136 ± 40 µm (p<0.001). The mean superficial epithelial cell density of the bulbar conjunctiva reduced significantly after 2 hours of lens wear in the superior region by 453 ± 1106 cells/mm2 (p<0.05) and the temporal region by 332 ± 924 cells/mm2 (p=0.05). Reduction in cell density was mirrored by a significant increase in mean cell diameter (p<0.05). No significant difference (superior and temporal, p>0.05) was observed in the density of inflammatory cells (IC) and dendritic cells (DC) before and after lens wear. Only a small number of subjects showed any significant change in density of IC (n=2; mean, 78 ± 10 cells/mm2) and DC (n=3; mean, 124 ± 45 cells/mm2) in the temporal conjunctiva with MScCL wear.
Conclusions :
This is the first study to show morphological changes in the bulbar conjunctiva after MScCL wear. Reduced superficial epithelial cell density may reflect cell compression and spreading as a result of lens pressure. Changes in DC and IC density were noted in only a few subjects. IVCM is a useful tool to study morphological changes in the bulbar conjunctiva associated with MScCL wear. Further research is needed to understand the long-term effect of MScCLs wear on conjunctival morphology.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.