Sir,
The paper by Ajit et al1 that was recently published in Eye described a new methodology of graphically presenting adherence data, using an electronic dosing monitor. The concept of using such a device to provide meaningful, graphical information is potentially favourable to the clinician in identifying patterns of adherence. However, the idea of collecting this information for all patients is probably unrealistic and unlikely to be cost-effective.
Lowering intraocular pressure (IOP) to reduce or halt the progression of visual field loss is the only currently available intervention for patients with glaucoma. Measuring IOP to assess efficacy has been standard practice ever since topical anti-glaucoma therapy was commenced. If a therapeutic regimen is adhered to, a reduction in IOP would be expected on repeat measurement a priori. Theoretically, therapeutic outcome would be both an objective and a practical measure of adherence. However, to date there is no consistent evidence of a relationship between adherence and IOP.2 Failure to identify such a relationship could be explained by the lack of a quantified correlation, or could be attributed to the methodological quality of the studies examining such a correlation being poor. However, it is more likely that the complexities of assessing the level of IOP due to individual differences (types of glaucoma and diurnal variance), together with regression to the mean, lead to ‘noisy data'.
The methodology used by Ajit et al1 stated that 100 patients at their initial interview had their IOP recorded. However, no further discussion of the IOP data was done in the paper. Assuming that Ajit et al had the intention of collecting IOP data to study any relationship between IOP and adherence, it would be interesting if their findings could be published, particularly given the potential value to the glaucoma clinician of learning how IOP measures might correlate with adherence.
The authors declare no conflict of interest.
References
- Ajit RR, Fenerty CH, Henson DB. Patterns and rate of adherence to glaucoma therapy using an electronic dosing aid. Eye. 2010;24:1338–1343. doi: 10.1038/eye.2010.27. [DOI] [PubMed] [Google Scholar]
- Olthoff CM, Schouten JS, van de Borne BW, Webers CA. Noncompliance with ocular hypotensive treatment in patients with glaucoma or ocular hypertension an evidence-based review. Ophthalmology. 2005;112:953–961. doi: 10.1016/j.ophtha.2004.12.035. [DOI] [PubMed] [Google Scholar]