Evolution of soft contact lens coatings

Area of Science:

• Ophthalmology
• Materials Science

Background:

• Giant papillary conjunctivitis (GPC) is a common complication associated with soft contact lens wear.
• The role of surface deposits in the pathogenesis of GPC requires further investigation.

Purpose of the Study:

• To examine the nature and progression of surface deposits on soft contact lenses using scanning electron microscopy.
• To determine if deposits persist on lenses even after routine cleaning.

Main Methods:

• Scanning electron microscopy was used to analyze 22 soft contact lenses worn for various durations.
• Unworn lenses and lenses worn by both naive and asymptomatic contact lens wearers were examined.
• Lenses were analyzed after different wear times (30 minutes, 8 hours) and after routine cleaning.

Main Results:

• Even after 30 minutes of wear, lenses showed approximately 50% surface coverage with cellular and mucus-like material.
• Eight hours of wear resulted in approximately 90% surface coverage with more complex deposits.
• Routinely worn and cleaned lenses exhibited extensive, complex coatings (>90% surface coverage), with deposits remaining even after professional cleaning.

Conclusions:

• All worn soft contact lenses develop surface coatings that increase in complexity over time.
• These persistent deposits may be a significant factor in the development of giant papillary conjunctivitis.