Abstract
Purpose CAPTCHA (completely automated public turing test to tell computers and humans apart) was designed as a spam prevention test. In patients with visual impairment, completion of this task has been assumed to be difficult; but to date, no study has proven this to be true. As visual function is not well measured by Snellen visual acuity (VA) alone, we theorized that CAPTCHA performance may provide additional information on macular disease-related visual dysfunction. Methods This was designed as a pilot study. Active disease was defined as the presence of either intraretinal fluid (IRF) or subretinal fluid (SRF) on spectral-domain optical coherence tomography. CAPTCHA performance was tested using 10 prompts. In addition, near and distance VA, contrast sensitivity, and reading speed were measured. Visual acuity matched pseudophakic patients were used as controls. Primary outcome measures were average edit distance and percent of correct responses. Results 70 patients were recruited: 33 with active macular disease and 37 control subjects. Contrast sensitivity was found to be significantly different in both the IRF (p < 0.01) and SRF groups (p < 0.01). No significant difference was found comparing the odds ratio of average edit distance of active disease (IRF, SRF) vs. control (OR 1.09 (0.62, 1.90), 1.10 (0.58, 2.05), p=0.77, 0.77) or percent correct responses of active disease vs. control (OR 0.98 (0.96, 1.01), 1.09 (0.58, 2.05), p=0.22, 0.51) in CAPTCHA testing. The goodness of fit using logistic regression analysis for the dependent variables of either IRF or SRF did not improve accounting for average edit distance (p=0.49, p=0.27) or percent correct (p=0.89, p=0.61). Conclusions Distance VA and contrast sensitivity are positively correlated with the presence of IRF and SRF in active macular disease. CAPTCHA performance did not appear to be a significant predictor of either IRF or SRF in our pilot study.
Highlights
Computer automated public turing test to tell computers and humans apart (CAPTCHA) has gained popularity in recent years as an electronic visual challenge-response test of human authenticity (Figure 1). e test involves a user correctly entering all alphanumeric symbols displayed in a text prompt
Hazel et al found that low-contrast visual acuity, contrast sensitivity, and binocular reading speed had the strongest correlation with visual quality of life in 28 patients with active macular disease from either presumed ocular histoplasmosis syndrome (POHS) or exudative macular degeneration [11]
Our study hypothesized that patients with macular disease, defined as active diabetic macular edema (DME) or exudative age-related macular degeneration (AMD), would perform poorly on a series of CAPTCHA prompts compared to visually matched pseudophakic controls
Summary
Computer automated public turing test to tell computers and humans apart (CAPTCHA) has gained popularity in recent years as an electronic visual challenge-response test of human authenticity (Figure 1). e test involves a user correctly entering all alphanumeric symbols displayed in a text prompt. CAPTCHA testing is useful in thwarting potential hackers and spamming, passing it can prove challenging to those with visual impairment [1, 2]. Responders with diseases affecting central vision, in particular the macula, may have even more difficulty completing these tasks. To this end, quantifying patients’ level of performance on CAPTCHA testing may provide a noninvasive, sensitive, and easy way to perform method of potentially monitoring active macular disease. CAPTCHA performance may provide an advantage over other visual acuity metrics methods in assessing central visual acuity. Snellen testing often fails to address aspects of important visual impairment to patients for daily functioning and quality of life. Elliott et al reported on a series of thirty-three patients
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