Goldmann versus Disposable Applanation Tonometer Tips in Glaucoma Patients and Normal Subjects.

PURPOSE: To assess agreement of intraocular pressure (IOP) measured with Goldmann applanation and disposable Luneau SA applanation prisms in glaucoma patients compared with normal subjects.

METHODS

In a prospective comparative study, one eye per primary open-angle glaucoma (POAG) patient was measured for IOP using Goldmann and disposable Luneau SA (Tonojet) applanation tonometry prisms. Glaucoma patients found with IOP < 21 mmHg were compared to an age-matched group of normal subjects. The main outcomes measured were IOP and the difference in IOP between either prism. Bland-Altman plots were used to study the agreement between measurements. Regression analysis was applied to either group.

RESULTS

One hundred and four POAG patients (eyes) were enrolled into this study. Seventy-one of them were found with IOPs < 21 mmHg, and were compared to 71 normal subjects (eyes). The mean difference between either prism was almost similar, 2.0 ± 2.0 and 2.1 ± 1.7 mmHg in the glaucoma and normal eye groups, respectively. Bias of two SD from the mean ranged from -1.8 to 5.8 mmHg in glaucoma group and -1.2 to 5.4 mmHg with normal subjects (p < 0.0001 in either group). The inaccuracy was non-systematic with glaucoma patients while was systematic with normal subjects.

CONCLUSIONS

The disagreement between disposables and standard Goldmann tips followed different patterns in glaucoma patients when compared with normal subjects. The use of the Goldmann tip is advised with glaucoma patients.