Applanation tonometry in silicone hydrogel contact lens wearers

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Engineering

Background:

• Previous research confirmed accurate intraocular pressure (IOP) measurement through conventional soft (hydrogel) therapeutic contact lenses.
• IOP measurement via soft contact lenses can be influenced by lens water content and center thickness.
• Silicone hydrogel contact lenses, favored for high oxygen permeability, are increasingly used therapeutically.

Purpose of the Study:

• To evaluate the accuracy of intraocular pressure (IOP) measurement in subjects wearing silicone hydrogel contact lenses.
• To determine if silicone hydrogel contact lenses affect the reliability of IOP readings.

Main Methods:

• A cohort study design was employed.
• Intraocular pressure (IOP) was measured using Goldmann applanation tonometry.
• Measurements were taken both without a contact lens and with a silicone hydrogel contact lens in situ.

Main Results:

• The study included 20 eyes from 10 healthy volunteers.
• The mean difference in IOP measurements between wearing and not wearing a contact lens was -0.5 mmHg (±0.89 mmHg).
• A high correlation coefficient (0.89) was observed, with no statistically significant difference (p=0.19) between the two measurement conditions.

Conclusions:

• Accurate intraocular pressure (IOP) measurement using Goldmann applanation tonometry is achievable through silicone hydrogel contact lenses.
• Silicone hydrogel contact lenses do not significantly impede reliable IOP assessment.
• This finding supports the use of silicone hydrogel therapeutic contact lenses without compromising IOP monitoring.