Rebound Tonometry over Soft Contact Lenses

Area of Science:

• Ophthalmology
• Optometry
• Biomedical Engineering

Background:

• Goldmann applanation tonometry (GAT) is the established gold standard for intraocular pressure (IOP) measurement.
• Accurate IOP measurement is critical for diagnosing and managing glaucoma and ocular hypertension.

Purpose of the Study:

• To evaluate the accuracy of rebound tonometry for measuring IOP while patients wear hydrogel and silicone hydrogel contact lenses (CLs).
• To assess the influence of different CL powers on IOP measurements using rebound tonometry.

Main Methods:

• 117 eyes of 61 habitual contact lens wearers (without prior ocular conditions) were included.
• Intraocular pressure was measured using a rebound tonometer (iCare) with and without hydrogel/silicone hydrogel CLs of varying powers (-9.50 to +10.00 D).
• Paired t-test and correlation analysis were used to compare measurements and assess reliability.

Main Results:

• A significant positive correlation (r = 0.59) was observed between IOP measurements with and without CLs.
• The mean IOP measured with CLs (20.74±5.19 mmHg) was slightly higher (1.95 mmHg difference, P <0.01) than without CLs (18.79±4.36 mmHg).
• Increased central corneal thickness (CCT) positively correlated with increased rebound tonometry measurement error (r = 0.43).

Conclusions:

• Rebound tonometry demonstrates good reliability for IOP measurement over various contact lenses.
• This method is feasible and accurate for clinical use in contact lens wearers.
• Further research may explore the impact of CL material and thickness on IOP measurement accuracy.