Comparison of accuracy of transpalpebral Diaton vs Goldmann tonometry in patients with and without prior ophthalmic surgery (LASEK)

Poster Details

First Author: EmilChynn USA

Co Author(s):    Tatiana Bakaeva              

Abstract Details

Purpose:

To evaluate the accuracy of transpalpebral Diaton vs. Goldmann applantation tonometry (GAT) in non-glaucomatous patients with and without prior ophthalmic surgery (LASEK).

Setting:

: Single refractive subspecialty practice.

Methods:

The study was conducted on two groups of non-glaucomatous patients: (1) individuals without previous eye surgery (N = 60 (117 eyes), Age: 30.5 ± 8.3 (range 18-51), males/females = 20/40) and (2) a different group of patients 3 months after myopic LASEK (N = 38 (72 eyes), Age: 29.7 ± 9.6 (range 18-51), males/females = 14/24). IOP was measured by transpalpebral Diaton tonometry and Goldmann applantation tonometry (GAT) using standard protocols. Central corneal thickness (CCT) was measured using ultrasound pachymetry.

Results:

Mean CCT in the non-surgical group was 554 µm ± 32.5 µm (range 471-637 µm). In the post-LASEK group mean CCT was less: 499 µm ± 51 µm (range 399-610 µm) because of prior central corneal ablation; this difference was significant (p < 0.01). In the non-surgical group mean GAT IOP was 16.9 mm Hg ± 2.6 (range 10-21 mm Hg); mean Diaton IOP was 14.4 mm Hg ± 2.6 (range 9-20 mm Hg); this difference was significant (p < 0.01). There was a positive correlation between GAT and Diaton measurements (r = 0.46), which became stronger with correction for CCT (r = 0.61). In contrast, mean GAT IOP in post-LASEK group was lower than mean Diaton IOP (12.1 mm Hg ± 2.9 vs. 15.4 mm Hg ± 2.8); this difference was also significant (p < 0.01). There was a positive correlation between GAT and Diaton measurements postop (r = 0.41), which became stronger with correction for CCT (r = 0.65). Diaton measurements had no correlation with CCT in both non-surgical patients (r = -0.09) and post-LASEK patients (r = -0.04) whereas GAT was strongly influenced by CCT in both non-surgical and post-LASEK patients (r = 0.37 and 0.46 respectively).

Conclusions:

1. Diaton IOP correlates well with GAT IOP in both non-surgical and post-LASEK patients. 2. Unlike GAT, Diaton measurements of IOP are not dependent on CCT in both non-surgical and post-LASEK patients. 3. Clinicians may consider preferring Diaton over GAT to measure IOP in post-LASEK patients, and in non-surgical patients with low CCT, for greater accuracy. FINANCIAL INTEREST: NONE