Our Research
The Re-development of the Kay Picture Test
In a comprehensive research study carried out by Liverpool University Directorate of Orthoptics and Vision Science and a number of clinical orthoptic departments across the UK and The Retina Foundation of the Southwest, USA, the Kay Picture Test was shown to be valid and repeatable within the limits of current gold standards with high testability.
Picture Recognition
The chosen pictures were shown to be most easily recognised by a group of 420 children, including 33 non-English speakers and 53 with developmental delay.
Legibility
The visual acuities of 50 subjects were compared using 25 new Pictures, Landolt C and ETDRS in two phases. The six pictures chosen where those to have consistent legibility (see table below).
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Comparison with Current Tests
113 subjects were assessed, and the mean bias indicated similar results for Pictures, ETDRS and Lea symbols. However, the limits of agreement were wider for Lea symbols than Kay Pictures when each was compared to ETDRS. The limits of agreement for ETDRS versus Lea symbols were slightly wider than for ETDRS versus Kay Pictures.
Test Retest Variability
There was low test retest variability on 100 subjects, comparable to published values for other tests. Paired t-test analysis demonstrated no significant difference between test one and test two in either ETDRS (p=0.1) or Kay Pictures (p=0.1). The mean bias for both tests was 0.01 logMAR with similar limits of agreement.
Conclusion
The single crowded optotype design not only produces a reliable VA assessment, but allows the introduction of the crowding phenomenon to a younger age group with picture optotypes that are of equal resolution acuity and recognition for the targeted age group.
- O’Connor AR Kay H, Thomson D, Newsham D. Redesigning the Kay Picture Test for Children. Invest Ophthalmol Vis Sci April 2010 Volume 51, Issue 13. Redesigning the Kay Picture Visual Acuity Test for Children | IOVS | ARVO Journals
- Milling, A., Newsham, D., Tidbury, L., O’Connor, A.R. and Kay, H., 2015. The redevelopment of the Kay picture test of visual acuity. British and Irish Orthoptic Journal, 13, pp.14–21. DOI: http://doi.org/10.22599/bioj.97
- O’Connor AR, Milling A. Normative data for the redesigned Kay Pictures visual acuity test. JAAPOS Volume 24, Issue 4, p242-244 August 2020. DOI: 10.1016/j.jaapos.2020.05.00.
Kay Picture Test Screening Book
£88.00
Kay Picture Test Screening Chart
£37.00
Kay Picture Test Linear Crowded Book
£112.00
Kay Picture Test Single Crowded Book
£112.00
Kay Letter Test
£112.00
