Toric contact lens designs in hyper-oxygen materials

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Materials Science

Background:

• Significant astigmatism necessitates toric soft contact lenses, particularly for continuous wear.
• Toric lens designs often increase thickness, potentially compromising oxygen transmissibility and causing mechanical trauma.
• Optimizing toric lens orientation and fit is crucial for developing thinner, safer designs.

Purpose of the Study:

• To investigate the mechanisms of toric soft lens orientation and fit.
• To understand the influence of lid dynamics on toric lens reorientation.
• To inform the development of improved, thinner toric lens designs.

Main Methods:

• Analysis of video recordings of toric soft lenses during reorientation.
• High-speed video recording to capture dynamic lid-lens interactions.
• Assessment of gravity's effect on prism-ballasted soft lenses.

Main Results:

• Gravity has minimal effect on prism-ballasted lenses within 30 degrees of the base-down position.
• Lid position correlates with toric lens orientation.
• Lid-induced rotation occurs during blinks, with the lower lid's influence potentially overriding the upper lid's.
• Lower lid influence depends on its position, tightness, and lateral movement.

Conclusions:

• Understanding lid-lens mechanics is key to optimizing toric soft lens design.
• Further development can lead to thinner toric lenses with enhanced oxygen transmissibility and reduced mechanical trauma.
• Knowledge gained can guide the creation of advanced toric silicone hydrogel lenses.