Aims To evaluate the technique of eye drop instillation in patients with glaucoma and assess factors associated with a good technique. Methods A cross-sectional observational study of 85 participants using self-administered topical medication for glaucoma or ocular hypertension. Patients were asked to demonstrate how they normally instil eye drops using a 5-ml bottle of sterile artificial tear solution. The procedure was recorded and assessed by two masked graders. Whether the patient had been previously shown how to instil drops, the number of eye medications used, and self-perceived difficulty of using drops were also recorded. Univariable logistic regression was performed to relate each variable to drop technique and variables with P<0.2 were included in a multivariable logistic regression analysis. Results 54.1% (46/85) of patients had a poor drop technique, 11.8% (10/85) missed the eye, 15.3% (13/85) touched the tip of the bottle to the bulbar conjunctiva or cornea, and 27.1% (23/85) touched the eyelid or lashes with the bottle tip. 81.2% (69/85) could not recall being shown how to instil eye drops. In the multivariable model, previous instruction regarding drop instillation technique was significantly associated with good technique (adjusted OR=8.17, 95% CI 2.02–33.05, P=0.003) and increasing age was associated with poor technique (adjusted OR=0.95, 95% CI 0.91–0.99, P=0.017). Conclusions Education relating to eye drop instillation technique is significantly associated with a patient's ability to instil drops correctly. The assessment of a patient’s ability to instil eye drops correctly should be a routine part of the glaucoma examination.

Glaucoma is a leading cause of irreversible loss of vision.¹ Although blindness is the most feared consequence of glaucoma, there is growing evidence that even relatively mild disease may have a significant impact on quality of life (QoL). The impact of glaucoma on vision-related QoL has previously been investigated using questionnaire-based self-reported assessments such as the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25).^2-4 Cross-sectional studies using the NEI VFQ-25 have demonstrated an association between glaucomatous visual field loss and QoL, but the reported relationships have been generally weak.^5-7 A possible reason for this is that patients with slowly progressive glaucomatous damage may adapt to reduce the impact of visual loss on activities of daily living. In fact, a study by Medeiros et al⁸ demonstrated that patients with faster decline in binocular visual field (BVF) sensitivity had worse deterioration in NEI VFQ-25 scores during follow-up.

To evaluate the diagnostic ability of macular ganglion cell and inner plexiform layer measurements in glaucoma, obtained using swept source (SS) and spectral domain (SD) optical coherence tomography (OCT) and to compare to circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements. The study included 106 glaucomatous eyes of 80 subjects and 41 eyes of 22 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Macular ganglion cell and inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC) and cpRNFL thickness were assessed using SS-OCT and SD-OCT, and area under the receiver operating characteristic curves (AUCs) were calculated to determine ability to differentiate glaucomatous and healthy eyes and between early glaucomatous and healthy eyes. Mean (± standard deviation) mGCIPL and mGCC thickness were thinner in both healthy and glaucomatous eyes using SS-OCT compared to using SD-OCT. Fixed and proportional biases were detected between SS-OCT and SD-OCT measures. Diagnostic accuracy (AUCs) for differentiating between healthy and glaucomatous eyes for average and sectoral mGCIPL was similar in SS-OCT (0.65 to 0.81) and SD-OCT (0.63 to 0.83). AUCs for average cpRNFL acquired using SS-OCT and SD-OCT tended to be higher (0.83 and 0.85, respectively) than for average mGCC (0.82 and 0.78, respectively), and mGCIPL (0.73 and 0.75, respectively) but these differences did not consistently reach statistical significance. Minimum SD-OCT mGCIPL and mGCC thickness (unavailable in SS-OCT) had the highest AUC (0.86) among macular measurements. Assessment of mGCIPL thickness using SS-OCT or SD-OCT is useful for detecting glaucomatous damage, but measurements are not interchangeable for patient management decisions. Diagnostic accuracies of mGCIPL and mGCC from both SS-OCT and SD-OCT were similar to that of cpRNFL for glaucoma detection.