Ocular effects of hard gas-permeable-lens extended wear.
Thirty-five myopic subjects were fitted with rigid gas-permeable lenses for 6 months of extended wear (EW). These lenses had an average oxygen transmissibility of 37 x 10(-9) (cm x ml x O2)/(s x ml x mm Hg). For six monthly morning visits subjects reported with one eye patched; corneal thickness, corneal curvature, refractive error, endothelial photomicroscopy, and slitlamp examinations were done on both eyes. The average morning corneal swelling was 5.9 +/- 3.3%. Corneal curvature showed 0.24 +/- 0.44 D flattening in the steep meridian and 0.20 D steepening in the flat meridian. Spectacle refraction and corrected visual acuity changes were small in the spherical and cylindrical components. Complications that were important clinically included 10% lens adherence syndrome, 20% superficial limbal keratitis, 6.5% epithelial microcysts, and some increase in endothelial polymegathism. No infections, red eye responses, or infiltrative keratitis were observed during the 6-month follow-up period. These results suggest that hard-lens EW is feasible and that lenses with this Dk/L value will meet oxygen requirements for many patients; however, some patients will require lenses of higher oxygen transmissibility to avoid undesirable complications.
Polse
K A
KA
School of Optometry, University of California, Berkeley.
Rivera
R K
RK
Bonanno
J
J
D002452:Cell Count; D003262:Contact Lenses, Extended-Wear; D003263:Contact Lenses, Hydrophilic; D003315:Cornea / Q000502:physiology*; D004728:Endothelium, Corneal / Q000473:pathology; D005740:Gases; D006801:Humans; D010539:Permeability; D012030:Refractive Errors / Q000503:physiopathology / Q000628:therapy
D005740:Gases