The parameter stability of a high dk rigid lens material

Woods, C. and Efron, N. 1999, The parameter stability of a high dk rigid lens material, Contact lens and anterior eye, vol. 22, no. 1, pp. 14-18, doi: 10.1016/S1367-0484(99)80026-5.

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Title The parameter stability of a high dk rigid lens material
Author(s) Woods, C.ORCID iD for Woods, C.
Efron, N.
Journal name Contact lens and anterior eye
Volume number 22
Issue number 1
Start page 14
End page 18
Total pages 5
Publisher Elsevier BV
Place of publication Amsterdam, Netherlands
Publication date 1999
ISSN 1367-0484
Keyword(s) parameter stability
rigid gas permeable contact lenses
daily wear
extended wear
Summary The use of rigid materials with high oxygen permeability (Dk) is on the increase, their major benefit being the reduction of hypoxia. However, there is a reluctance to use these materials possibly due to increased surface scratching, reduced wettability, increased deposition, reduced life expectancy and parameter instability. Considering parameter stability, various studies have demonstrated contradictory results or used high Dk materials based on the silicone acrylate polymer. This study was designed to investigate whether the parameters of a high Dk rigid fluorocarbon contact lens material changed during daily wear and extended wear schedules. Thirty five subjects, divided into group groups, Group I wore the lens on a daily wear basis, whereas those in Group II wore the lens on a monthly extended wear basis. The parameters and integrity of the lenses were monitored in both groups every 3 months. For lens integrity a statistically significant increase in surface scratching was demonstrated for the lenses worn by the subjects of both groups over the time of the study (Group I, F=7.990, P <0.0001 [ANCOVA]; Group II, F=6.241, P=0.003 [ANCOVA]). The only parameter to show a statistically significant variation over the study period was that of centre thickness for the lenses worn by the subjects in Group I (F=3.976, P=0.0063 [ANCOVA]), with a mean reduction in centre thickness of 0.022 mm at the 12 month visit.

No change was noted for either group or between groups for the other parameters measured. This study demonstrates that the parameters of rigid contact lenses manufactured from high Dk fluorocarbons are stable with only a non-clinically significant reduction in centre thickness for the contact lenses worn by the subjects in Group I.
Language eng
DOI 10.1016/S1367-0484(99)80026-5
Field of Research 119999 Medical and Health Sciences not elsewhere classified
Socio Economic Objective 970111 Expanding Knowledge in the Medical and Health Sciences
HERDC Research category C1.1 Refereed article in a scholarly journal
Copyright notice ©1999, British Contact Lens Association
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Document type: Journal Article
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School of Medicine
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