Comparison of rebound and applanation tonometry in the management of patients treated for glaucoma or ocular hypertension.
OBJECTIVE
To compare intraocular pressure (IOP) values obtained with the iCare rebound tonometer (RBT) with values obtained with the Goldmann applanation tonometer (GAT) in patients with glaucoma and ocular hypertension, and to evaluate the impact of possible differences on management decisions.


METHODS
The IOP was measured with the iCare RBT and GAT in 45 consecutive patients in a nurse-led glaucoma unit. The outcome measures were the IOP difference between the methods and the 95% limits of agreement (LoA) for IOP measurements. In all subjects where the IOP readings differed by >3 mmHg between the RBT and GAT, two ophthalmologists were independently asked to recommend treatment and/or follow-up intervals, based on the patients' clinical data and the IOP values.


RESULTS
The RBT overestimated the IOP compared with GAT in 67% of the cases (30/45). In 78% (35/45) the IOP difference was within +/-3 mmHg. When an extreme value of 15 mmHg difference was excluded, the 95% LoA was +/-4.31 mmHg. In five of the 10 patients with an IOP difference of > +/- 3 mmHg the difference would have led to change in therapy; in three more patients the follow-up interval would have been changed. In the remaining two patients the difference in IOP would not have led to any change in management.


CONCLUSIONS
The mean difference between RBT and GAT was small (1.5 +/- 3 mmHg) compared with the published repeatability of GAT values. Yet, the difference was found to have clinical implications in 18% (8/45) of the patients.
Department of Ophthalmology, Skellefteå County Hospital, Skellefteå, Sweden.
Jeannette B
JB
Rehnman
Lene
L
Martin
D000368:Aged; D000369:Aged, 80 and over; D004867:Equipment Design; D005260:Female; D005901:Glaucoma / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009798:Ocular Hypertension / Q000503:physiopathology* / Q000628:therapy; D018709:Statistics, Nonparametric; D014065:Tonometry, Ocular / Q000379:methods*