Benjamin Esterman (1906-1994) and the binocular visual field scoring grid that became a world standard for assessing driver eligibility

Esterman Visual Field Testing Using a Virtual Reality Headset in Glaucoma

Purpose

To test the use of a virtual reality visual field headset (VRVF) for implementation of the Esterman visual field (EVF) test as compared with standard automated perimetry (SAP) among people with glaucoma.

Design

Experimental design.

Subjects

Patients with mild to severe glaucoma ranging from 10 to 90 years who presented for follow-up at a glaucoma clinic in Miami, Florida were eligible.

Methods

Participants performed the EVF test on both SAP and VRVF. Five glaucoma-trained ophthalmologists were then asked to rate all anonymized SAP and RVF tests as a "pass" or "failure" based on Florida state law.

Main Outcome Measures

Point-by-point concordance between original VRVF EVF test results and SAP EVF test results was calculated using the Kappa statistic. Concordance between SAP and VRVF was secondarily assessed with a conditional logistic regression based on the pass-failure determinations by the glaucoma-trained ophthalmologists. Interrater agreement on test pass-failure determinations was also calculated. Finally, test results on SAP versus VRVF were compared based on Esterman efficiency score (EES), the number of correct points divided by the number of total points, and duration of testing.

Results

Twenty-two subjects were included in the study with ages ranging from 14 to 78 years old. Concordance between VRVF and SAP test using point-by-point analysis was poor (κ = 0.332, [95% confidence intervals {CI}: 0.157, 0.506]) and somewhat increased using pass-failure determinations from ophthalmologists (κ = 0.657, [95% CI: 0.549, 0.751]). Ophthalmologists were more likely to agree amongst themselves on pass-failure determinations for VRVF tests (κ = 0.890, [95% CI: 0.726, 0.964]) than for SAP (κ = 0.590, [95% CI: 0.372, 0.818]); however, VRVF demonstrated significantly lower EES than SAP (median EES difference: 4.5 points, P = 0.021).

Conclusions

This pilot study is the first to assess the implementation of the EVF test using a virtual reality headset. Based on the weak overall agreement between VRVF and SAP, the current VRVF EVF test is not an acceptable determinant of driver's licensing. However, ophthalmologists were more likely to agree amongst themselves on VRVF test reports than on SAP reports. With further testing and improvement, virtual reality may eventually become a portable and convenient method for administering the EVF test.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Reliability of Binocular Esterman Visual Field Test in Patients with Glaucoma and Other Ocular Conditions

The binocular Esterman visual field test (EVFT) of 120 points was the first method to quantify the defects in the binocular visual field. It is used in many parts of the world as a standard test to determine whether an individual has the visual capabilities to drive safely. In Japan, it is required for the grading and issuance of visual disability certificates. The purpose of this study was to determine the reliability of the EVFT results. We studied 104 patients who had undergone the binocular EVFT at Mie University Hospital. Their mean age was 68.0 ± 11.4 years, and the best-corrected visual acuity of the better eye was 0.18 ± 0.38 logMAR units. The EVFT was performed twice on the same day, and the results of the first and second tests were compared. The mean Esterman scores for the first and second test were 89.3 ± 30.5 and 89.1 ± 30.2, respectively, and the test times were 338.9 ± 86.8 and 336.7 ± 76.4 s, respectively. The differences were not significant (p = 0.69 and p = 0.33). In the Bland-Altman analyses (second-first test) of the Esterman scores, the mean difference was 0.38 without significant fixed errors (p = 0.20) or proportional errors (p = 0.27). The limits of agreement within the 1.96 standard deviation were -8.96 to +9.45 points. The agreement rate for the most peripheral 24 test points was significantly lower than the agreement rate for the other 96 test points (p < 0.01). The agreement rate of the upper visual field was significantly lower than that of the lower field (p < 0.01). The overall reliability rate of the EVFT is acceptable, but the peripheral and upper test points have relatively low reliability rates. These findings are important for interpretations of the EVFT results.

Vision rehabilitation in glaucoma patients

PURPOSE OF REVIEW

Vision rehabilitation services are important but underutilized resources for patients with glaucoma. Glaucoma and its impact on vision can affect patients' abilities to read and drive, two activities of daily living that are associated with quality of life and functional independence. In this review, we provide an overview of low vision, discuss barriers to vision rehabilitation, and outline various strategies and interventions to optimize visual function and quality of life in patients with glaucoma.

RECENT FINDINGS

Studies have shown that glaucoma negatively impacts reading, driving and overall quality of life. Decreased visual acuity, visual field loss and reduced contrast sensitivity play a role. Low vision services and interventions can help patients maximize visual function and improve their quality of life. Barriers to receiving these services exist at multiple levels and an increased awareness and integration into routine ophthalmic care are needed to deliver comprehensive care.

SUMMARY

Glaucoma is one of the leading causes of low vision. Ophthalmologists who treat glaucoma often tend to focus on objective measures to monitor progression and disease severity, but the functional impact of glaucoma should also be addressed. Low vision services can benefit patients, particularly for reading and driving, and should be considered as an essential component of patient care.

Comparison of visual requirements and regulations for obtaining a driving license in different European countries and some open questions on their adequacy

We reviewed the current state of knowledge regarding visual function and its suitability as part of medical examinations for driving licenses. We focused only on Group 1 drivers. According to previous studies, visual acuity, which is the most common test, is weakly associated with a higher risk of road accidents, with a greater role of visual field. The inclusion of the visual field test in medical examinations is therefore important, but the actual limit value is still unclear and further research in specific situations is needed. Color vision impairment was not found a threat to traffic safety. Contrast sensitivity decreases with age and is affected by abnormal eye conditions. Resulting glare can lead to an increased risk of traffic accidents during night driving in the elderly and others with conditions that impair contrast sensitivity. However, the universal cut-off limits have not been established either. The current European Union (EU) regulations therefore reflect minimum common denominator across the member states which may not entirely translate to optimal driving safety. Due to these open questions, standardized testing in simulators or on polygons that simulate real life conditions would be needed to better determine safe limits of visual function in different conditions. As there is a need to have better standardization across Europe regarding the requirements and rules regarding driving licenses in European countries, we first analyzed existing rules and compared them with each other, also in terms of deviations from the EU directive itself. We reviewed the literature in this field and prepared proposals for a more optimal regulation of the rules in the future. Particular attention is paid to the new method of examining the visual field that was created to respect the European directive. The paper can serve as a basis of information for research teams to design further protocols, as it gathers research findings to date on the importance and impact of various visual functions on driving safety, as well as a starting point for a debate on revising existing rules for obtaining and maintaining licenses, as it compares the current regulations in European countries and differences between them.