Purpose Eff ectiveness of clinical glaucoma treatment may be dependent on the
patient’s adherence (A) with eye drop treatment. ! e relation between non-adherence
(NA) and intraocular pressure (IOP) is not yet well understood, due to methodological
weaknesses in the studies performed so far. ! e goal of this study was to investigate the
association between NA with eye drop treatment, IOP and degree of visual fi eld (VF)
defects in a large sample of glaucoma patients.
Methods A multi-center cross-sectional survey was performed in 973 patients in 60
ophthalmologic centers in Belgium. NA was assessed by a written self-report question
asking patients how many times he/she had forgotten to administer eye drops during
the past 2 weeks. Answer options ranged from never, seldom, once a week to daily. ! e
patients indicating they had skipped 1 or more administrations were classifi ed as NA.
Current IOP (mmHg) and VF defects were measured with a Goldmann applanation
tonometer and perimeter, respectively, at the same time as the NA assessment.
Results 603 out of 937 (64%) questionnaires were available for analysis. 39.5% of the
patients reported to be NA. NA patients showed a signifi cant higher current IOP of
the left eye than A patients (16.12 +/- 3.15 vs 15.58 +/- 2.83; p=0.030). No signifi cant
diff erence in IOP of the right eye was found between NA and A patients (16.13 +/-
3.53 vs 16.02 +/- 7.61; p=0.843). ! e degree of visual fi eld defects was not signifi cantly
related to NA.
Conclusion Because of the diff erence in IOP of the left eye between A and NA patients,
NA should be carefully monitored as part of glaucoma management. Yet, prospective
studies are needed to confi rm the relationship between NA and poor outcomes.