Underestimated IOP Reading of Goldmann Applanation Tonometry from Dermatochalasis

1. Narong Tungpakorn, MD
2. Manchima Makornwattana, MD

Department of Ophthalmology, Faculty of Medicine Thammasat University, Pathumtani, Thailand

PURPOSE: To evaluate the effect of dermatochalasis on intraocular pressure (IOP) measured by the Goldmann applanation tonometer

DESIGN: Prospective comparative study

METHODS: A total of 60 samples had clinically dermatochalasis and were included in the study. Only one eye of an individual was included in the data analysis for the study. Goldmann applanation measurements with and without tapped eyelid were performed randomly by the same ophthalmologist, with a 5-min interval break. Statistical analysis was performed using paired-t test. Statistical significance was considered at p< 0.05.

RESULTS: Mean age was 69.9±9.9 years (range, 43-98 years). The average first IOP reading without tapped eyelid was 14.20±4.98 mm Hg (range, 1-34 mm Hg), and the average second IOP reading with tapped eyelid was 10.32±4.80 mm Hg (range, 0-22 mm Hg). Paired-t test showed significant differences between the IOP reading with and without tapped eyelids with 95% confidence interval (95%CI) between 2.51-5.25 mm Hg. The mean difference was 3.88±5.30 mm Hg and much significantly lower in the IOP reading with tapped eyelid (p=0.001).

CONCLUSION: Dermatochalasis is a common finding seen in elderly persons and may affect Goldmann tonometry to underestimate the IOP. This could cause misclassification of glaucomatous patients and influence the clinical management as well as the decision-making associated with the glaucomatous treatments.