The performance of iPad-based noise-field perimeter versus Humphrey Field Analyser in detecting glaucomatous visual field loss

Abstract

Background To conduct a preliminary evaluation of the feasibility of visual field fast (VFF), a free iPad-based noise-field perimeter, in detecting glaucomatous scotomas versus the clinical-standard Humphrey visual field (HVF) test. VFF confronts subjects with a screen of flickering stimulus, allowing the immediate perception of scotomas. Methods This was a cross-sectional observational study of 66 glaucoma patients (66 eyes) and 30 healthy controls (30 eyes). All patients had no other visual field disorders. VFF was compared against HVF in terms of whole field and quadrants for the following: (1) correspondence in scotoma detection. (2) Agreement and correlation of the scotoma size (percentage of abnormal visual field area). (3) Test duration. Other domains tested included: (1) correlation of VFF scotoma area with the severity of visual field loss on HVF (mean deviation, MD; visual field index, VFI). (2) Repeatability of VFF. (3) Patient descriptors of scotomas. Results Using HVF pattern deviation plot as a reference, VFF detected 52/57 (91.2%) of glaucoma subjects with 1 false-positive (control) (kappa = 0.86). 146/184 (79.3%) of abnormal quadrants (visual field defect present) were localized and 23/157 (14.6%) healthy quadrants were falsely identified as abnormal (kappa = 0.61). VFF underestimated scotoma area as compared to HVF (21.0% versus 44.0%, p < 0.01) but correlated positively ( r = 0.268, p = 0.044) with HVF area and negatively with VFI ( r = −0.340, p = 0.01) and MD ( r = −0.398, p < 0.01). Using HVF total deviation plot as reference, VFF’s glaucoma detection rate remained unchanged (kappa = 0.86) with similar quadrant detection (kappa = 0.68). However, a greater underestimation of scotoma area was observed (21.0% versus 85.4%, p < 0.01). VFF’s quantitative repeatability was excellent for whole field (intraclass correlation coefficient, ICC: 0.96; p < 0.0001) and quadrants (ICC: 0.82–0.96; all p < 0.001). Qualitatively, 35/37 (94.6%) of subjects reported reduced luminance and flicker in scotomas, with similar morphologies on retests. VFF is faster than HVF SITA-Standard in glaucoma (3.60 ± 1.85 min versus 6.92 ± 1.12 min, p < 0.01) and control (1.12 ± 0.486 min versus 5.16 ± 0.727 min, p < 0.01). Conclusion This early model of VFF accurately detected scotomas with high repeatability. However, its accuracy in localizing and quantifying the scotoma can be improved. Considering its portability and cost-effectiveness, VFF demonstrated potential as a general screening tool for moderate-to-severe glaucoma.

Home-Based Perimetry for Glaucoma: Where Are We Now?

“…Their publication dates ranged between 2005 and 2021. The majority were cross-sectional clinical-based studies and were conducted in USA, 29,37,40,41 India, 27,30 UK, 26,31 Australia, 33,36 Singapore, 24 Greece, 34 Nepal, 35 Denmark, 38 and Philippines. 39 Two home-based longitudinal studies were conducted in UK 25 and Australia 28 , while one was a multicenter clinical-based study conducted in UK and India.…”

“…39 Two home-based longitudinal studies were conducted in UK 25 and Australia 28 , while one was a multicenter clinical-based study conducted in UK and India. 32 Participants were recruited from clinics and had detailed ophthalmological examinations, except in 5 studies 24,32,34,40,41 where examinations were not reported. Three studies 25,28,32 included patients with glaucoma or ocular hypertension, 11 studies 24,26,27,[29][30][31]33,[36][37][38]41 included glaucoma patients and healthy controls, 3 studies 35,39,40 also included patients with other diagnosis, and 1 study 34 did not specify participant diagnosis.…”

“…Based on our QUA-DAS-2 guidance, studies were considered to have a "high" risk of bias with regard to patient selection as they were either selected in a predetermined, nonrandomized manner; or recruited from a selected population 24,26,29,30,[33][34][35]37,38 or excluded patients with unreliable test results 24,30,37,38,41 or unable to finish tests. 39 With respect to conduction and interpretation of index test and reference standard, only 2 studies were considered to have a "low" risk of bias 24,35 ; 2 studies were rated as "high" risk of bias for index test as the used threshold was not prespecified and 2 studies had "low" risk of bias for reference standard 26,38 ; 7 studies were rated as "unclear" for both domains. 29,30,33,34,37,39,41 Flow and timing domain was assigned with "low" risk of bias in most studies 24,26,[33][34][35][37][38][39]41 except in 1 study where it was assigned with "high" risk of bias because <80% of participants were included in the analysis 30 and in 1 study where it was rated as "unclear."…”

“…39 With respect to conduction and interpretation of index test and reference standard, only 2 studies were considered to have a "low" risk of bias 24,35 ; 2 studies were rated as "high" risk of bias for index test as the used threshold was not prespecified and 2 studies had "low" risk of bias for reference standard 26,38 ; 7 studies were rated as "unclear" for both domains. 29,30,33,34,37,39,41 Flow and timing domain was assigned with "low" risk of bias in most studies 24,26,[33][34][35][37][38][39]41 except in 1 study where it was assigned with "high" risk of bias because <80% of participants were included in the analysis 30 and in 1 study where it was rated as "unclear." 29…”

“…Diagnostic accuracy for glaucoma was assessed in 11 studies 24,26,29,30,[33][34][35][37][38][39]41 (Table 3), whereas accuracy for detection of glaucoma progression was assessed in 3 studies. 25,28,32 Diagnostic accuracy data distinguishing mild/ moderate diseased patients from healthy controls and avoiding unit-of-analysis issues (eg, on a per-patient rather than per-VF point basis) were available only for 4 studies, presented graphically in Figure 2.…”