Comparison of Changes in Ocular Surface Status after Wearing Orthokeratologic and Rigid Gas Permeable Lens

PURPOSE: To evaluate the differences in dry eye and meibomian gland dysfunction (MGD) by comparing ocular surface status before and after wearing an orthokeratologic (OK) lens and rigid gas permeable (RGP) lens made of the same material. METHODS: The ocular surface and meibomian gland statuses of 12 eyes of 12 OK lens wearers (OK lens group) and 16 eyes of 16 RGP wearers (RGP lens group) were evaluated before and 1 and 3 months after lens wearing. Ocular surface disease index (OSDI), tear film break-up time (TBUT), Schirmer's test I, and ocular surface staining score were evaluated for ocular surface parameters. Meibomian gland function was evaluated by assessing lid margin abnormality, meibomian gland expressibility, and meibum quality. RESULTS: TBUT and ocular surface staining score after 1 and 3 months of wearing an OK lens were significantly aggravated (p= 0.004, p < 0.001). The MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were aggravated after 1 and 3 months of wearing an OK lens (p < 0.001, p < 0.001, p < 0.001, p= 0.002). After 1 and 3 months of wearing an RGP lens, OSDI, TBUT, and ocular surface staining score were aggravated (all p < 0.001). The MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were aggravated after 1 and 3 months of wearing an RGP lens (all p < 0.001). MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were significantly more aggravated in the RGP lens group than in the OK lens group after 3 months (p < 0.001, p < 0.001, p= 0.001, p < 0.001). CONCLUSIONS: Use of OK and RGP lenses affects ocular surface status. Especially, meibomian gland parameters and OSDI showed greater changes in RGP lens wearers than OK lens wearers.

Comparison of Changes in Ocular Surface Status after Wearing Orthokeratologic and Rigid Gas Permeable Lens

PURPOSE: To evaluate the differences in dry eye and meibomian gland dysfunction (MGD) by comparing ocular surface status before and after wearing an orthokeratologic (OK) lens and rigid gas permeable (RGP) lens made of the same material. METHODS: The ocular surface and meibomian gland statuses of 12 eyes of 12 OK lens wearers (OK lens group) and 16 eyes of 16 RGP wearers (RGP lens group) were evaluated before and 1 and 3 months after lens wearing. Ocular surface disease index (OSDI), tear film break-up time (TBUT), Schirmer's test I, and ocular surface staining score were evaluated for ocular surface parameters. Meibomian gland function was evaluated by assessing lid margin abnormality, meibomian gland expressibility, and meibum quality. RESULTS: TBUT and ocular surface staining score after 1 and 3 months of wearing an OK lens were significantly aggravated (p= 0.004, p < 0.001). The MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were aggravated after 1 and 3 months of wearing an OK lens (p < 0.001, p < 0.001, p < 0.001, p= 0.002). After 1 and 3 months of wearing an RGP lens, OSDI, TBUT, and ocular surface staining score were aggravated (all p < 0.001). The MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were aggravated after 1 and 3 months of wearing an RGP lens (all p < 0.001). MGD grade, lid margin abnormality, meibomian gland expressibility, and meibum quality were significantly more aggravated in the RGP lens group than in the OK lens group after 3 months (p < 0.001, p < 0.001, p= 0.001, p < 0.001). CONCLUSIONS: Use of OK and RGP lenses affects ocular surface status. Especially, meibomian gland parameters and OSDI showed greater changes in RGP lens wearers than OK lens wearers.

The Effect of RGP Lens and Reverse Geometry Lens on Apoptosis in Rabbit Cornea

PURPOSE: To investigate the cytotoxic effect of rigid gas permeable(RGP) and reverse geometry lens(RGL) on rabbit corneal cells. METHODS: In 36 white rabbits, right eyes were worn with either RGP or RGL. Left eyes were served as control. The rabbits were sacrificed at 1, 3, 7, 14 days after fitting and 7, 14 days after removal. Morphological changes of the basal epithelial cells and stromal keratocytes were observed using the light and transmission electron microscopy. The samples were examined after TUNEL staining in 3 high power fields (x400). RESULTS: In control eyes, 2.26% of central corneal epithelial cells showed apoptosis. After RGP wearing, the epithelial apoptosis decreased by 0.32% compared to control eyes(2.17%) at 14 days(p<0.001), and returned to 1.55% at 14 days after lens removal(2.04% in control, p=0.161). After RGL wearing, the degree of apoptosis was also lower than control(3.22%) by 0.30% at 14 days(p=0.003). However, it increased to 0.75% at 14 days after lens removal(1.67% in control, p=0.077). A few TUNEL positive fibroblasts were found in superficial stroma in both RGP and RGL group, but not in control eyes. CONCLUSIONS: Both RGP and RGL wearing may decrease the degree of apoptosis in corneal epithelium and lead the apoptosis in corneal stroma. The degree of apoptosis was recovered after lens removal, suggesting the process might to be reversible. The fitting with RGL induced apoptosis of keratocyte more than the fitting with RGP did. It suggests that the RGL wearing may be less physiologic than RGP wearing.