Recovery from induced corneal edema and endothelial morphology after long-term PMMA contact lens wear.

Abstract

PURPOSE:

To study the effect of long-term polymethyl methacrylate (PMMA) contact lens wear (CLW) on corneal endothelial morphology and corneal hydration control (CHC).

METHODS:

Sixteen long-term PMMA CL wearers (mean duration of wear 20.8 +/- 8.39 SD years; mean age 40.37 years +/- 10.47 SD) served as subjects and 14 age-matched, non-lens wearing subjects (mean age 41.29 years +/- 10.15 SD) served as controls. Corneal function was assessed by measuring the corneal thickness recovery rate (PRPH) after induced edema from a hypoxic stress load. Endothelial morphology was assessed by taking specular microscopy photographs, digitizing the images, and calculating the cell density, size, and coefficient of variation of cell size (CV).

RESULTS:

Morphologic analysis showed a significant decrease in mean endothelial cell density (2147 vs. 2865, p < 0.01), an increase in mean cell size (582 vs. 381, p = 0.001), and an increase in polymegethism (CV, 0.32 vs. 0.26, p < 0.01) for PMMA lens wearers compared to agematched controls. Corneal function as measured by PRPH was not significantly different for PMMA lens wearers compared to controls when taken as a whole. However, a subgroup of PMMA lens wearers (seven eyes, four subjects) did show a substantial reduction in PRPH. These subjects also showed a strong relation between reduced PRPH, morphology, and years of lens wear (r2 = 0.99).

CONCLUSIONS:

Longterm PMMA CLW leads to increased polymegethism in most, if not all, cases and results in a substantial decrease in corneal function in some cases.

• Authors: T T McMahon, K A Polse, N McNamara, M A Viana
• Journal: Optometry and vision science : official publication of the American Academy of Optometry (Optom Vis Sci) Vol. 73 Issue 3 Pg. 184-8 (Mar 1996) ISSN: 1040-5488 [Print] United States
• PMID: 8725020 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Methylmethacrylates

Topics

• Adult
• Body Water (metabolism)
• Cell Count
• Contact Lenses, Extended-Wear
• Corneal Edema (etiology, metabolism, pathology)
• Endothelium, Corneal (metabolism, pathology)
• Humans
• Hypoxia (complications)
• Methylmethacrylates
• Middle Aged