Diagnostic accuracy of an iPad application for detection of visual field defects

BACKGROUND/OBJECTIVES

Tablet-based perimetry could be used to test for glaucomatous visual field defects in settings without easy access to perimeters, although few studies have assessed diagnostic accuracy of tablet-based tests. The goal of this study was to determine the diagnostic accuracy of iPad perimetry using the visualFields Easy application.

SUBJECTS/METHODS

This was a prospective, cross-sectional study of patients undergoing their first Humphrey Field Analyser (HFA) visual field test at a glaucoma clinic in India. Participants underwent 24-2 SITA Standard HFA testing and iPad-based perimetry with the visualFields Easy application. Reference standards for both visual field loss and suspected glaucoma were determined by ophthalmologist review of HFA results and optic disc photographs. Receiver operating characteristic curves were constructed to assess diagnostic accuracy at various test thresholds.

RESULTS

203 eyes from 115 participants were included, with 82 eyes classified as moderate or worse glaucoma. iPad perimetry had an area under the receiver operating characteristic (AUROC) curve of 0.64 (95% CI 0.57 to 0.71) for detection of any visual field defect relative to HFA and an AUROC of 0.68 (0.59 to 0.76) for detection of moderate or worse glaucoma relative to ophthalmologist examination. At a set specificity of 90%, the sensitivity of iPad perimetry for detection of moderate or worse glaucoma was 35% (22-48%).

CONCLUSIONS

iPad perimetry using the visualFields Easy application had inadequate diagnostic accuracy to be used as a screening tool for glaucoma in this South Indian population.

Diagnostic Accuracy of Frequency-Doubling Technology and the Moorfields Motion Displacement Test for Glaucoma

PURPOSE

Portable perimetric testing could be useful for community-based glaucoma screening programs. Frequency-doubling technology (FDT) and the Moorfields motion displacement test (MDT) are portable perimeters that have shown promise as potential screening tools for glaucoma. This study's goal was to determine the diagnostic accuracy of FDT and MDT for visual field defects and glaucoma.

DESIGN

Prospective, cross-sectional, diagnostic accuracy study.

PARTICIPANTS

A consecutive series of patients aged ≥ 50 years who presented to a glaucoma clinic in South India and had never undergone Humphrey field analyzer (HFA) visual field testing in the past.

METHODS

Participants underwent 24-2 Swedish Interactive Thresholding Algorithm (SITA) Standard HFA perimetry, FDT perimetry, MDT perimetry, and iPad perimetry using visualFields Easy in random order. Ophthalmologist grades of HFA and optic nerve head photographs were used as reference standards for glaucoma and field defect presence. Receiver operating characteristic curves were constructed to assess the diagnostic accuracy of various parameters for each test.

MAIN OUTCOME MEASURES

Sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC).

RESULTS

Overall, 292 eyes from 173 participants were included, with 112 eyes classified as moderate or worse glaucoma. For moderate or worse glaucoma detection, the best parameter on FDT was mean deviation (MD) (AUROC, 0.84; 95% confidence interval [CI], 0.79-0.89) and the best parameter on MDT was global probability of true damage (GPTD) (AUROC, 0.87; 95% CI, 0.82-0.91). When specificity was set to 90%, the sensitivity for detection of moderate or worse glaucoma was 55% (95% CI, 39%-68%) for FDT MD and 62% (95% CI 52%-71%) for MDT GPTD.

CONCLUSIONS

Frequency-doubling technology and MDT perimetry had fair diagnostic accuracy for glaucoma detection when administered to naïve test takers in this South Indian population. Although not appropriate for use as a sole glaucoma screening test, these perimetric tests may be useful as ancillary tests.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Comparison of Structural, Functional, Tonometric, and Visual Acuity Testing for Glaucoma: A Prospective Diagnostic Accuracy Study

PURPOSE

To determine the diagnostic accuracy of potential screening tests for moderate to advanced glaucoma.

DESIGN

Prospective diagnostic test accuracy study.

PARTICIPANTS

The study enrolled a consecutive series of patients aged ≥50 years who presented to a glaucoma clinic in South India without ever having received automated visual field testing.

METHODS

All participants underwent 8 index tests: OCT of the peripapillary retinal nerve fiber layer, optic disc photography, Moorfield's Motion Displacement Test (MDT), frequency doubling technique perimetry, noncontact tonometry, pneumatonometry, presenting visual acuity, and best-corrected visual acuity. Participants also underwent stereoscopic photographs and Humphrey visual fields, which were used by 2 ophthalmologists to arrive at the reference standard diagnosis of moderate to advanced glaucoma.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio.

RESULTS

A total of 217 people were enrolled; 321 eyes from 180 participants had all tests performed. Of these, 127 eyes (40%) were classified as having moderate to advanced glaucoma. Among the 8 tests, OCT best optimized sensitivity (84%, 95% confidence interval [CI], 76-90) and specificity (75%, 95% CI, 68-81). Moorfield's Motion Displacement Test was the best perimetric test, with a sensitivity of 91% (95% CI, 85-96) and specificity of 53% (95% CI, 44-61). Pressure and vision tests were not sensitive (e.g., sensitivity of 16%, 95% CI, 9-23 for noncontact tonometry and 23%, 95% CI, 15-31 for best-corrected visual acuity). Moorfield's Motion Displacement Test identified 16 of 127 eyes (13%) with glaucoma that were not captured by OCT, but also had false-positive results in 65 of 194 eyes (34%) without glaucoma that OCT correctly classified as negative.

CONCLUSIONS

OCT had moderate sensitivity and fair specificity for diagnosing moderate to advanced glaucoma and should be prioritized during an initial assessment for glaucoma.

Accuracy of autorefraction in an adult Indian population

Purpose

Autorefractors allow non-specialists to quickly assess refractive error, and thus could be a useful component of large-scale vision screening programs. In order to better characterize the role of autorefraction for public health outreach programs in resource-limited settings, the diagnostic accuracy of two autorefractors was assessed relative to subjective refraction in an adult Indian population.

Methods

An optometrist refracted a series of patients aged ≥50 years at an eye clinic in Bangalore, India using the Nidek ARK-900 autorefractor first, followed by the 3nethra Royal autorefractor, and then subjective refraction. The diagnostic accuracy of each autorefractor for myopia, hyperopia, and astigmatism was assessed using subjective refraction as the reference standard, and measures of agreement between refractions were calculated.

Results

A total of 197 eyes in 104 individuals (mean age 63 ± 8 years, 52% female) were evaluated. Both autorefractors produced spherical equivalent estimates that were on average more hyperopic than subjective refraction, with a measurement bias of +0.16 D (95%CI +0.09 to +0.23D) for Nidek and +0.42 D (95%CI +0.28 to +0.54D) for 3nethra. When comparing pairs of measurements from autorefraction and subjective refraction, the limits of agreement were approximately ±1D for the Nidek autorefractor and ±1.75D for the 3Nethra autorefractor. The sensitivity and specificity of detecting ≥1 diopter of myopia were 94.6% (95%CI 86.8–100%) and 92.5% (95%CI 88.9–97.5%) for the Nidek, and 89.2% (95%CI 66.7–97.4) and 77.5% (95%CI 71.2–99.4%) for the 3Nethra. The accuracy of each autorefractor increased at greater levels of refractive error.

Conclusions

The sensitivity and specificity of the Nidek autorefractor for diagnosing refractive error among adults ≥50 years in an urban Indian clinic was sufficient for screening for visually significant refractive errors, although the relatively wide limits of agreement suggest that subjective refinement of the eyeglasses prescription would still be necessary.