Comparison of self-refraction using a simple device, USee, with manifest refraction in adults

Abstract

BackgroundThe USee device is a new self-refraction tool that allows users to determine their own refractive error. We evaluated the ease of use of USee in adults, and compared the refractive error correction achieved with USee to clinical manifest refraction.MethodsSixty adults with uncorrected visual acuity <20/30 and spherical equivalent between –6.00 and +6.00 diopters completed manifest refraction and self-refraction.ResultsSubjects had a mean (±SD) age of 53.1 (±18.6) years, and 27 (45.0%) were male. Mean (±SD) spherical equivalent measured by manifest refraction and self-refraction were –0.90 D (±2.53) and –1.22 diopters (±2.42), respectively (p = 0.001). The proportion of subjects correctable to ≥20/30 in the better eye was higher for manifest refraction (96.7%) than self-refraction (83.3%, p = 0.005). Failure to achieve visual acuity ≥20/30 with self-refraction in right eyes was associated with increasing age (per year, OR: 1.05; 95% CI: 1.00–1.10) and higher cylindrical power (per diopter, OR: 7.26; 95% CI: 1.88–28.1). Subjectively, 95% of participants thought USee was easy to use, 85% thought self-refraction correction was better than being uncorrected, 57% thought vision with self-refraction correction was similar to their current corrective lenses, and 53% rated their vision as “very good” or “excellent” with self-refraction.ConclusionSelf-refraction provides acceptable refractive error correction in the majority of adults. Programs targeting resource-poor settings could potentially use USee to provide easy on-site refractive error correction.

Towards Automating Retinoscopy for Refractive Error Diagnosis

“…Interestingly, 43.2% of our predictions were within ±0.5D, and 74.0% were within ±1D of the prescription given by an experienced optometrist using subjective refraction. These results are at par with the self-subjective refraction methods, like Eye Netra [32] (38.0% predictions within 0.5D) and USee [4] (77.5% predictions within 1D). Though these results are promising, the mean absolute error of manual retinoscopy (0.18 ± 0.27D) and autorefractor (0.33 ± 0.33D) highlight a scope for improvement (refer to Table 3).…”

“…A scale embedded on the sides of the tube depicts the spherical refractive error. USee [4] is another self-refraction tool. It comprises of a glass frame with an adjustable progressive lens system for each eye placed in front of a 3mm rectangular slit.…”

“…To summarize, commercial vision screeners (like Plusoptix, SPOT, QuickSee, Eye Netra, and SVOne AR) though clinically evaluated, are expensive and require a minimum skill level to obtain reliable measurements. On the other hand, low-cost solutions [4,24,25,61] have limited evaluation with respect to refractive error range and/or age group. Most importantly, none of the proposed solutions rely on the retinoscopy principle, which requires minimal patient cooperation, and is considered the best starting point for subjective refraction [34].…”

Innovative Diagnostic Tools for Ophthalmology in Low-Income Countries

“…Moreover, a study in urban Chinese children similarly found good visual acuity with self-refraction, but greater spherical and cylindrical refractive errors were associated with less accurate results as the range for the devices are limited to −6 to +6 D. Additionally, the adjustable glasses could not correct astigmatism [18]. Adjustable glasses are easy to use as is evident in a study that looked at users of USee which found positive results in 95% of the users [19].…”

Eligibility for the use of ready-made spectacles among children in a school-based programme in Ghana

“…Thus, they enable the provision of spectacles for children with a difference in prescription in their two eyes which is less than or equal to 1.00 dioptre [19]. It has also been found that they can be dispensed for spherical equivalent of up to ±6.00 dioptres as reported in one of the studies which used a variant of it [20].…”