Comparison of IOP Measurements Between Ocular Response Analyzer and Goldmann Applanation Tonometry Before and After Corrective Refractive Surgery

Townley, J. Richard

Comparison of IOP Measurements Between Ocular Response Analyzer and Goldmann Applanation Tonometry Before and After Corrective Refractive Surgery

Monday, April 28, 2014: 1:51 PM

Room 155 (Boston Convention and Exhibition Center)

J. Richard Townley III, MD, Wilford Hall Ambulatory Surgery Center, San Antonio, TX, USA

Vincent Vu, MD, Wilford Hall Medical Center, Lackland AFB, TX, USA

Jason N. Crosson, MD, SAUSHEC, San Antonio, TX, USA

Matthew Caldwell, MD, Wilford Hall Ambulatory Surgical Center, Lackland AFB, TX, USA

Paul M. Drayna, MD, Wilford Hall Ambulatory Surgery Center, Lackland AFB, TX, USA

Vasudha A. Panday, MD, Wilford Hall Ambulatory Surgery Center, San Antonio, TX, USA

Narrative Responses:

Purpose
Goldmann Applanation Tonometry (GAT), based on the Imbert-Fick law, doesn’t take into account corneal changes due to refractive surgery. This study compares intraocular pressure (IOP) measurements obtained with the Reichert Ocular Response Analyzer (ORA) to GAT on subjects who were evaluated and treated with laser refractive surgery.

Methods
This was a retrospective study analysis of IOP measurements taken with GAT or the ORA before and after refractive surgery. 248 eyes pre-operative evaluations and 66 eyes that had undergone refractive surgery were assessed for differences between the different IOP measuring methods before and one month after refractive surgery. Data was pulled from the ORA’s database and AHLTA (Armed Forces Health Longitudinal Technology Application), an electronic medical record. Statistical analysis was performed with paired t tests.

Results
The mean pre-op GAT, ORA adjusted Goldmann (ORAg), and ORA corneal corrected (ORAcc) were 15.59 ± 2.79, 15.15 ± 3.84, and 15.62 ± 3.99,with no significance difference between measurements. Mean post-op GAT and ORAg was also similar (15.97 ± 3.68 and 16.12 ± 5.57). Pre and post-op GAT (15.64± 3.00 and 15.97 ± 3.68) showed no difference. However, there was a difference detected in post-op GAT and ORAcc (15.97 ± 3.68 and 19.51 ± 6.09) p<0.001 and a difference noted between pre and post-op ORAcc (15.05 ± 3.17 and 19.52 ± 6.09) p< 0.001.

Conclusion
The ORA is an effective tool for assessing post-refractive surgery patient’s IOP. Post-op ORAcc IOP was higher than postop GAT or ORAg. Since the ORAcc is less affected by changes in corneal biomechanics, the ORA offers mores sensitivity in detecting elevated IOP following refractive surgery.