Assessment of the Spot vision screener performance in detecting amblyopia and strabismus in Nepal: a prospective diagnostic accuracy study.

BACKGROUND

Photoscreening can quickly detect amblyopia and strabismus, but there is little data on the performances of screening devices in low-income countries. The goal of this study was to assess the diagnostic accuracy of the Spot vision screener in Nepal.

METHODS

This prospective study enrolled a random sample of children 3-8 years of age seen in a pediatric ophthalmology clinic in Nepal. A trained ophthalmic assistant screened each child with using the Spot. A fellowship-trained pediatric ophthalmologist masked to screening results examined the children and to determine whether amblyopia or strabismus was present. This examination was the reference standard for diagnostic accuracy.

RESULTS

Of 219 consecutive children seen in the clinic, 109 were randomly selected for enrollment, of whom 91 were enrolled (mean age, 6.4 ± 1.4 years; 63.2% male). Twenty (22%) were diagnosed with amblyopia; 7 (7.7%), with strabismus. Of the 91, 31 (34.1%) failed the Spot screening according to standardized examination failure criteria. For detecting amblyopia, failure on the Spot for any reason had a sensitivity of 90.0% (95% CI, 68.3%-98.8%) and specificity of 81.7% (70.7%-89.9%). For detecting strabismus, failure on the Spot for any reason had a sensitivity of 71.4% (29.0%-96.3%), and specificity of 69.0% (58.0%-78.7%). For amblyopia or strabismus, sensitivity was 83.3% (62.9%-95.3%), and specificity was 83.6% (72.5%-91.5%). Positive predictive value in the clinic population was 64.5% (45.4%-80.8%) and negative predictive value was 93.3% (83.8%-98.2%).results

CONCLUSIONS

In this cohort, the Spot vision screener had relatively high sensitivity and moderate specificity for detecting amblyopia and strabismus, demonstrating its ability to correctly identify the majority of cases in a low-resource setting, although over-referral may result from its relatively low specificity and inaccurate autorefraction values.