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Visual decrement with deposit accumulation of HEMA contact lenses
K W Gellatly1, N A Brennan, N Efron
1Department of Optometry, University of Melbourne, Parkville, Australia.
Insights
Deposit accumulation on hydroxyethyl methacrylate (HEMA) contact lenses significantly reduces vision. Unacceptable vision loss and deposits typically occur after 12 months or 4,000 hours of daily wear.
Area of Science:
- Ophthalmology
- Materials Science
Background:
- Hydroxyethyl methacrylate (HEMA) contact lenses are widely used.
- Deposit accumulation on contact lenses can lead to vision impairment.
Purpose of the Study:
- To assess the relationship between deposit accumulation and vision decrement in HEMA contact lens wearers.
- To determine the timeline for unacceptable vision loss and deposit formation.
Main Methods:
- Assessed vision decrement (high and low contrast visual acuity) in 51 patients.
- Classified deposit accumulation using the Rudko scale.
- Correlated vision acuity, deposit levels, and lens age.
Main Results:
- Both high and low contrast visual acuity decreased with increased lens deposition.
- Lens deposition and vision decrement worsened with increasing lens age.
- Unacceptable vision decrement and deposit formation generally occurred after 12 months or 4,000 hours of daily wear.
Conclusions:
- Clinicians can use these findings to link vision loss to deposit formation in HEMA lens wearers.
- The study provides a guideline for expected lens performance over time.
Abstract:
The vision decrement associated with deposit accumulation on hydroxyethyl methacrylate (HEMA) contact lenses was assessed in 51 patients presenting consecutively to a large clinic. Both high contrast visual acuity (HCA) and low contrast visual acuity (LCA) (logMAR) decreased with increased deposition (Rudko classification). Apart from being consistently lower than HCA, LCA offered no additional useful information. Both HCA and LCA worsened with lens age, whilst lens deposition increased with lens age (p less than 0.001). No associations between any of the above measures and patient symptoms were revealed. In general, unacceptable vision decrement and deposit formation occurred after 12 months or 4,000 h of daily lens wear. Clinicians can use the data presented in this paper to reconcile vision loss with deposit formation in patients wearing HEMA lenses.
