Abstract
Purpose:
To investigate the agreement of intraocular pressure (IOP) measurement using Dynamic Contour Tonometry (DCT) and Goldmann Applanation Tonometry (GAT) in eyes after vitrectomy with intraocular tamponade of gas, eyes after vitrectomy with no tamponade, and controls.
Methods:
In this prospective comparative study IOP was measured with GAT and DCT in 74 control eyes with no history of glaucoma or intraocular surgery, 20 gas-filled eyes one to three days after vitrectomy and 24 water-filled eyes with a history of vitrectomy. DCT measurements were accepted with a quality score of 3 or better. GAT and DCT measurements lower than 6mmHg were excluded.
Results:
The mean difference between GAT and DCT (GAT-DCT) in control eyes was -0.17 ± 3.4, in eyes after vitrectomy with no tamponade -0.36 ± 4.9, and in gas-filled eyes 4.08 ± 5.9 (p<0.001). IOP obtained by both instruments correlated significantly in the control group (r=0.30, p= 0.0099), and in the group with gas-filled eyes (r=0.78 , p<0.0001). There was no significant correlation in the water-filled eyes (r=0.24, p=0.25). No significant correlation was found between the differences of GAT and DCT (GAT-DCT) to the mean IOP of GAT and DCT in control eyes (r=-0.01, p=0.92) and water-filled eyes (r=-0.21, p=0.33). A significant correlation was found in the gas-filled eyes (r=0.87, p<0.0001).
Conclusions:
IOP as determined by DCT underestimates IOP in gas-filled eyes compared to GAT. GAT values were on average 4mmHg higher compared to DCT. The extent of IOP underestimation using DCT increases in higher IOP values. IOP evaluation after vitrectomy with gas endotamponade remains a difficult challenge.
Keywords: 762 vitreoretinal surgery •
568 intraocular pressure •
764 vitreous substitutes