Rigid lens dynamics: Lid effects
Carney, Leo G., Mainstone, Julia C., Carkeet, Andrew, Quinn, Thomas G., & Hill, Richard M. (1997) Rigid lens dynamics: Lid effects. The CLAO journal : official publication of the Contact Lens Association of Ophthalmologists, 23(1), pp. 69-77.
PURPOSE: Lid architecture, lid tension, blink action, and blink rate may all influence rigid lens centration and stability. The aims of this study were to assess the nature of the relationship between lid geometry and lens position and to examine the influence of lens-lid interactions on the association between lens position and lens center of gravity and mass. METHODS: Eight subjects (four with high riding lenses and four with low riding lenses) participated in the study. Each subject was fit with 12 lenses-six designs in each of two materials. Lens center of gravity was calculated and lens mass was measured in every case. For each lens, the following four lens dynamics variables were assessed over a five blink cycle for both the vertical and horizontal meridians: 1) initial lens position; 2) settled lens position; 3) amount of lens movement; and 4) rate of lens movement. Lower lid position and palpebral aperture height were measured for each subject. RESULTS: Graphical analysis showed that a low upper lid position and small palpebral aperture promoted superior lens decentration, while a high upper lid position and wide palpebral aperature predisposed an individual to inferior lens decentration. Significant lid-lens overlap was a common finding with high riding lenses in both the initial and settled lens positions. The results also suggested that while a rigid lens tended to become more stable as the lens center of gravity shifted further behind the corneal apex, this gravitational effect was reduced for lenses that interacted with the upper lid. CONCLUSIONS: Lid geometry can influence rigid lens centration and stability by modifying the effects of lens design and lens mass. We recommend that consideration be given to the nature of potential lens-lid interactions prior to lens fitting.
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|Item Type:||Journal Article|
|Keywords:||Contact Lenses, /adverse effects, Gravitation, Blinking/, physiology, Eyelids/, physiology, Foreign, Body Migration/, physiopathology, Cornea/anatomy & histology, Eyelids/anatomy & histology, Foreign, Body Migration/etiology, Humans, Mathematics, Regression Analysis, Research Support, Non, U, S, Gov't|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health|
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 1997 Contact Lens Association of Ophthalmologists|
|Copyright Statement:||Reproduced in accordance with the copyright policy of the publisher.|
|Deposited On:||31 Jan 2006|
|Last Modified:||09 Jun 2010 22:29|
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