Accuracy of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL in edematous corneas

Purpose: To investigate in vitro the accuracy of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL in edematous corneas. Methods: Experimental study included 20 freshly enucleated porcine eyes. Epithelium was debrided, and eyes were divided in four groups. Groups were immersed in 35%, 40%, 50%, and 60% glycerin solutions for 3 hours. Subsequently, globes were mounted in a special holder, and their intraocular pressure was hydrostatically adjusted. Intraocular pressure was measured by means of dynamic contour tonometry, Goldmann applanation tonometry, and Tono-Pen XL while adjusting true intraocular pressure to 17, 33, and 50 mm Hg. Ultrasound pachymetry was performed. Results: Mean corneal thickness was 914.5 ± 33.3 μm (730–1015 μm). In true intraocular pressure of 33 mm Hg, Goldmann applanation tonometry and dynamic contour tonometry significantly underestimated true intraocular pressure (mean Goldmann applanation tonometry: 14.7 ± 4.8 mm Hg, p