Posters - A COMPARISON OF THE VASCULAR RESPONSE TO EXTENDED WEAR OF CONVENTIONAL LOWER DK AND EXPERIMENTAL HIGH DK HYDROGEL CONTACT LENSES

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Posters

September 2002

A COMPARISON OF THE VASCULAR RESPONSE TO EXTENDED WEAR OF CONVENTIONAL LOWER DK AND EXPERIMENTAL HIGH DK HYDROGEL CONTACT LENSES

Kathy Dumbleton, MCOptom, MSc, Doris Richter, OD, MASc, Trefford Simpson, DipOptom, PhD, Desmond Fonn, DipOptom, MOptom, Centre for Contact Lens Research, UW; Robin Chalmers, OD, CIBA Vision, Atlanta, GA

Purpose:

Clinical decisions regarding the choice of lens material are usually driven by problems noted at initial patient presentation. There is a variation in redness among hydrogel lens wearers. The purpose of this analysis was to determine how patient specific the effect of hypoxia is on hyperemia and neovascularization.

Method:

This analysis investigated the impact of high (lotrafilcon A, HDK=140) and lower (etafilcon A, LDK=28) levels of oxygen on the development or resolution of ocular hyperemia and neovascularization over 6 months of extended wear (LDK n=32, HDK n=59) in a randomized clinical trial. A stratified analysis to determine how change in ocular redness depended on initial presentation was also conducted.

Results:

On a 0-100 point scale, HDK demonstrated an average 3 point increase in bulbar and 2 point increase in limbal hyperemia, and LDK showed an average 9 point increase in bulbar and 10 point increase in limbal hyperemia. The increase was significantly greater in LDK than in HDK (bulbar p=0.022, limbal p=0.001) and was greatest for LDK participants initially presenting with lower levels of hyperemia (n=21). There was a slight resolution of redness in participants initially presenting with higher levels of hyperemia (n=10) after wearing the HDK lenses. Neovascularization increased by 0.5 on a scale of 0-4 in LDK (p=0.00) but remained unchanged in HDK (p=0.713). The increase was most marked for the LDK group with lower levels of neovascularization at baseline.

Conclusions:

Following 6 months of extended wear the lower DK lenses resulted in increased ocular redness and the higher DK lenses resulted in no change or in some cases a decrease in ocular redness. Moderate neovascularization can also develop in 6 months of extended wear of lower DK hydrogels, while high DK lenses show no impact on neovascularization. Supported by CIBA Vision, Atlanta, GA

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A COMPARISON OF THE VASCULAR RESPONSE TO EXTENDED WEAR OF CONVENTIONAL LOWER DK AND EXPERIMENTAL HIGH DK HYDROGEL CONTACT LENSES - 117 KB

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