TY - GEN
T1 - Model of a contact lens and tear layer at static equilibrium
AU - Athukorallage, Bhagya
AU - Iyer, Ram
PY - 2013
Y1 - 2013
N2 - In this paper, we study the static stability of a spherical cap lens and a tear layer. The contact angle of the tear meniscus with the cornea and contact lens may have a range of values due to capillary effect hysteresis. As the lens is in static equilibrium all the forces and moments sum to zero. Capillary effect hysteresis is found to be a beneficial effect aiding the stability of the lens. The forces acting on the lens are its weight, force due to hydrostatic and atmospheric pressures and surface tension on the periphery of the lens due to the tear meniscus. The fixed parameters in the model are weight of the lens, coefficient of surface tension, magnitude of gravitational acceleration, density of the tear liquid and physical parameters of the lens such as the diameter and base curve radius. The adjustable parameters in the model are contact angles of the tear meniscus with the cornea and contact lens respectively and the position of the lens on the cornea. Numerical experiments suggest that there exists a range of values for the adjustable parameters that lead to physically reasonable solutions, for lens position; extent of overlap of the lower lid on the lens; pressure due to the lid on the lens; and the thickness of tear layer between the lens and the cornea.
AB - In this paper, we study the static stability of a spherical cap lens and a tear layer. The contact angle of the tear meniscus with the cornea and contact lens may have a range of values due to capillary effect hysteresis. As the lens is in static equilibrium all the forces and moments sum to zero. Capillary effect hysteresis is found to be a beneficial effect aiding the stability of the lens. The forces acting on the lens are its weight, force due to hydrostatic and atmospheric pressures and surface tension on the periphery of the lens due to the tear meniscus. The fixed parameters in the model are weight of the lens, coefficient of surface tension, magnitude of gravitational acceleration, density of the tear liquid and physical parameters of the lens such as the diameter and base curve radius. The adjustable parameters in the model are contact angles of the tear meniscus with the cornea and contact lens respectively and the position of the lens on the cornea. Numerical experiments suggest that there exists a range of values for the adjustable parameters that lead to physically reasonable solutions, for lens position; extent of overlap of the lower lid on the lens; pressure due to the lid on the lens; and the thickness of tear layer between the lens and the cornea.
UR - http://www.scopus.com/inward/record.url?scp=84883532000&partnerID=8YFLogxK
U2 - 10.1109/acc.2013.6580389
DO - 10.1109/acc.2013.6580389
M3 - Conference contribution
AN - SCOPUS:84883532000
SN - 9781479901777
T3 - Proceedings of the American Control Conference
SP - 3605
EP - 3612
BT - 2013 American Control Conference, ACC 2013
PB - Institute of Electrical and Electronics Engineers Inc.
Y2 - 17 June 2013 through 19 June 2013
ER -