Tonometry in all patients is the best way to prevent blindness

It is more cost-effective to perform routine tonometry in all initial ophthalmic patients than in none at all or in just high-risk glaucoma patients, according to a paper published in the March 2008 issue of Eye.

Using the A. Markov cost-effectiveness simulation model, A. Peeters and colleagues at Maastricht University Hospital, the Netherlands, analyzed and compared three case-finding strategies, measuring cost, proportion of patients becoming blind and years of blindness. The aim of the study was to determine the most cost-effective route for an ophthalmologist to detect and treat ocular hypertension (OH) and primary open-angle glaucoma (POAG) early in order to prevent blindness.

In the study, all patients underwent ophthalmoscopy, but tonometry was routinely performed to: (1) all initial patients, (2) high-risk patients only, or (3) no one. The population characteristics were based on data of 1000 initial patients, and transition probabilities were taken from the literature. The time-horizon of the model was 20 years, using an annual discount rate of 4%.

The researchers found that the costliest strategy - performing tonometry on all initial patients - led to least blindness. The incremental cost-effectiveness ratio, which shows extra costs per year of vision saved in comparison to the cheapest strategy (performing tonometry on no one), was found to be lower for performing tonometry on all initial patients than for performing it solely on high-risk patients. According to the study, it amounts to €1707, not including extra costs due to blindness (such as those associated with the use of disability facilities). When such costs exceed €1707 per patient per year, which is most likely, the first strategy (of performing tonometry on all initial patients) becomes cost saving.

From these results, the study concluded that the most cost-effective method of preventing blindness due to glaucoma is to routinely perform tonometry for all initial ophthalmic patients.