Is Palpation Sufficient for Estimation of IOP Immediately Following Cataract Surgery?

The aim of this study was to evaluate the accuracy of standard palpation techniques and Barraquer tonometry relative to Tono-Pen for measurement of postoperative intraocular pressure (IOP) immediately following routine micro-incision cataract surgery (MICS). We conducted a prospective comparative analysis of postoperative IOP immediately after MICS in a single academic outpatient surgery center. A random block of 166 eyes that underwent MICS at our institution was selected for inclusion. Exclusion criteria consisted of any complications including posterior capsule rupture. IOP was measured immediately postoperatively, first with palpation or a Barraquer tonometer, then with a Tono-Pen handheld applanation tonometer. Measurements obtained by each method were compared. The mean difference between IOP measurements obtained by palpation and Tono-Pen was 10 mmHg, 95% confidence interval (CI; 8, 12); whereas the mean difference between IOP measurements obtained by Barraquer tonometer and Tono-Pen was 2 mmHg, 95% CI (1, 3). IOP measurements acquired via palpation differed from their corresponding Tono-Pen measurements by > 5 mmHg in 48.0% of cases compared to only 5.9% of measurements acquired using a Barraquer tonometer. Spearman correlation coefficient for measurements obtained by standard palpation and Tono-Pen was r = 0.397 (p < 0.01) compared to r = 0.774 (p < 0.01) for those obtained by Barraquer tonometer and Tono-Pen. In conclusion, palpation is not an accurate method for estimating IOP immediately after cataract surgery compared to Tono-Pen. Appropriate measurement and adjustment of IOP at the end of cataract surgery may decrease complications such as cystoid macular edema. In settings where a Tono-Pen is not readily available, Barraquer tonometry may serve as a reasonable and cost-effective alternative.