Identifying Areas of the Visual Field Important for Quality of Life in Patients with Glaucoma

Abstract

PurposeThe purpose of this study was to create a vision-related quality of life (VRQoL) prediction system to identify visual field (VF) test points associated with decreased VRQoL in patients with glaucoma.MethodVRQoL score was surveyed in 164 patients with glaucoma using the ‘Sumi questionnaire’. A binocular VF was created from monocular VFs by using the integrated VF (IVF) method. VRQoL score was predicted using the ‘Random Forest’ method, based on visual acuity (VA) of better and worse eyes (better-eye and worse-eye VA) and total deviation (TD) values from the IVF. For comparison, VRQoL scores were regressed (linear regression) against: (i) mean of TD (IVF MD); (ii) better-eye VA; (iii) worse-eye VA; and (iv) IVF MD and better- and worse-eye VAs. The rank of importance of IVF test points was identified using the Random Forest method.ResultsThe root mean of squared prediction error associated with the Random Forest method (0.30 to 1.97) was significantly smaller than those with linear regression models (0.34 to 3.38, p<0.05, ten-fold cross validation test). Worse-eye VA was the most important variable in all VRQoL tasks. In general, important VF test points were concentrated along the horizontal meridian. Particular areas of the IVF were important for different tasks: peripheral superior and inferior areas in the left hemifield for the ‘letters and sentences’ task, peripheral, mid-peripheral and para-central inferior regions for the ‘walking’ task, the peripheral superior region for the ‘going out’ task, and a broad scattered area across the IVF for the ‘dining’ task.ConclusionThe VRQoL prediction model with the Random Forest method enables clinicians to better understand patients’ VRQoL based on standard clinical measurements of VA and VF.

Areas of the visual field important during reading in patients with glaucoma

“…We speculate the fact that the participants in our study had better acuity (worse eye acuity was considered the best predictor of responses to reading questions in the Murata et al study) and tended not to be very advanced in their condition may be causes for this inconsistency. The prominence of the superior left of the VF, apparent in the Murata study, was not observed in our study, while Murata et al [19] found no indication of the inferior-left section of the VF being important. However, we theorise that this may be a result of the fact that reading in Japanese tategaki format goes from top-right to bottom-left rather than from top-left to bottom-right.…”

“…Murata et al [19] observed that the inferior field is the main area of importance for reading, much like the results of this research, but their region is closer to fixation. We speculate the fact that the participants in our study had better acuity (worse eye acuity was considered the best predictor of responses to reading questions in the Murata et al study) and tended not to be very advanced in their condition may be causes for this inconsistency.…”

“…Only one other study has previously considered the relationship between the locations of the binocular VF and reading performance, and the respective results between that study and the present one are interesting to consider [19]. Murata et al [19] observed that the inferior field is the main area of importance for reading, much like the results of this research, but their region is closer to fixation.…”

“…The results of a recent UK study with the aim to explore which parts of the binocular VF may correspond most closely with day-to-day difficulties in patients with visual impairment, including a small number of glaucomatous patients, suggest that the central 5°of the VF are particularly important in reading [18]. A study with a similar experimental design, conducted on glaucomatous patients from Japan, found the inferior left hemifield area of the binocular VF to be linked to patient response to questions about reading [19]. That study also found evidence to suggest that points in the peripheral superior hemifield may impact letters and sentence responses.…”

A view on glaucoma—are we seeing it clearly?

“…25 The locality of an IVF defect might be much more important than a summary measure and there are some imaginative studies that have highlighted this. 26 We have recently attempted to derive clinically meaningful estimates of the prevalence of different types of binocular visual field loss, because this ought to inform how we should assess those with advanced bilateral glaucoma. 27 …”