What would an 'ideal' glaucoma examination be like? - A conjoint analysis of patients' and physicians' preferences.

PURPOSE: To structurally determine patients' and physicians' preferences for glaucoma diagnostic methods in order to improve glaucoma patient care and improve patient compliance with follow-up visits. METHODS: Forty-one patients with glaucoma and 32 ophthalmologists were included in this cross-sectional study. Profiles representing glaucoma examinations were created using conjoint analysis (CA). The following factors of a glaucoma examination method were evaluated: (1) examination comfort, (2) examination frequency, (3) follow-up examination necessary in case of suspicious result, (4) cost for the patient, (5) travel time to examination site, (6) sensitivity and (7) specificity of the examination method. RESULTS: Preferences were highest in both groups for examination sensitivity, followed by cost and specificity for the patient group. For the physician group, specificity was second most important, followed by cost. Least important was travel time for the patients and follow-up examinations for the physicians. CONCLUSIONS: Participants would rather pay more and travel longer to get a highly sensitive examination. This form of care is present in university eye hospitals. Consequently, it would be advisable to enhance capacities of these centers. Outpatient practices that offer glaucoma service should be fully equipped and should employ a glaucoma specialist.

Structure-Function Relationship Between Bruch's Membrane Opening-Based Optic Nerve Head Parameters and Visual Field Defects in Glaucoma.

PURPOSE: This study was performed to evaluate the structure-function relationship between Bruch's membrane opening (BMO) parameters of the optic nerve head (ONH) and visual field (VF) sensitivity. METHODS: Forty-six right eyes of 46 patients with open-angle glaucoma (OAG) in the patient group and 12 right eyes in the control group were included. Standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) were assessed. Three BMO-based distances and two areas of the neuroretinal rim were used for correlation: the minimum rim width (MRW), the perpendicular rim width (PRW), the horizontal rim width (HRW), the minimum rim area (MRA) within the neuroretinal tissue defined by the MRW, and the perpendicular rim area (PRA) within the neuroretinal tissue defined by the PRW. These parameters were correlated with global and sectoral VF sensitivities. Spearman's correlation coefficients between BMO parameters and global and sectoral VF sensitivities were obtained. RESULTS: Within the patient group, significant correlations could be observed between global and sectoral VF sensitivities and BMO parameters, with PRW and PRA showing the highest values. In the sectoral analysis the highest correlations were found for the temporal-inferior VF sector (MD-TI): PRW-TI (ρ = 0.72394; P < 0.00001) and PRA-TI (ρ = 0.77205; P < 0.00001). Minimum rim width and MRA performed more weakly than PRW and PRA. CONCLUSIONS: The BMO-based parameters PRW and PRA presented with a very good structure-function relationship in glaucoma patients, statistically at least equal to MRW and MRA. Using new BMO-based parameters might allow early objective assessments of functional glaucomatous impairments.

Evaluation of a vision-related utility instrument: the German vision and quality of life index.

PURPOSE: Multi-attribute utility instruments (MAUIs), which contain a descriptive system, including several health dimensions with associated levels of increasing severity, are used commonly to measure utilities. However, the validity of the descriptive systems rarely is examined using modern psychometric theory. Therefore, we evaluated the psychometric properties of the German version of the Vision and Quality of Life Index (VisQol), a six-item vision-related MAUI. METHODS: The German VisQol was self-administered to 340 patients and 280 controls. All subjects underwent a full ophthalmologic examination, including best-corrected visual acuity (VA) testing. The psychometric properties of the VisQoL were assessed using Rasch analysis. RESULTS: The VisQoL's descriptive system did not function in controls. In patients, after collapsing response categories to resolve disordered thresholds and omitting misfitting persons, the measurement properties (i.e., precision, unidimensionality, and targeting) of the German VisQoL were satisfactory. Most person misfit related to unexpected responses to item 4 ("organizing assistance"). Rasch-generated person estimates were not different between age categories, sex, or underlying ocular condition, but decreased significantly with presence of visual impairment in the better eye (LogMAR ≥ 0.5, 1.20 ± 4.62 compared to 3.46 ± 3.52, P < 0.001). CONCLUSIONS: The German VisQoL's descriptive system displayed adequate fit to the Rasch model after removal of a large proportion of patients with poor fit statistics. However, the wording of item four should be revised to reduce respondent confusion and measurement "noise." The scale's descriptive system does not function in a sample of visually unimpaired persons, most likely due to a lack of variance in the measured trait.

Visual impairment as a function of visual acuity in both eyes and its impact on patient reported preferences.

PURPOSE: To assess the impact of VA loss on patient reported utilities taking both eyes into account compared to taking only the better or the worse eye into account. METHODS: In this cross-sectional study 1085 patients and 254 controls rated preferences with the generic health-related (EQ-5D; n = 868) and vision-specific (Vision and Quality of Life Index (VisQoL); n = 837) multi-attribute utility instruments (MAUIs). Utilities were calculated for three levels of VA in the better and worse eyes, as well as for 6 different vision states based on combinations of the better and worse eye VA. RESULTS: Using the VisQoL, utility scores decreased significantly with deteriorating vision in both the better and worse eyes when analysed separately. When stratified by the 6 vision states, VisQoL utilities decreased as VA declined in the worse eye despite stable VA in the better eye. Differences in VisQoL scores were statistically significant for cases where the better eye had no vision impairment and the worse seeing fellow eye had mild, moderate or severe vision impairment. In contrast, the EQ-5D failed to capture changes in better or worse eye VA, or any of the six vision states. CONCLUSIONS: Calculating utilities based only on better eye VA or using a generic MAUI is likely to underestimate the impact of vision impairment, particularly when the better eye has no or little VA loss and the worse eye is moderately to severely visually impaired. These findings have considerable implications for the assessment of overall visual impairment as well as economic evaluations within eye health.