Evaluating a new logMAR chart designed to improve visual acuity assessment in population-based surveys.
OBJECTIVE
This study aimed to evaluate a new chart designed to improve the collection of visual acuity data in population-based surveys. The Reduced logMAR E chart (RLME) employs three letters per line, 'tumbling E' optotypes, and conforms to accepted contemporary design principles.


METHODS
The performance of the chart was assessed within a population-based glaucoma survey in Thailand. Performance indices were test-retest variability (TRV) and agreement with acuity data measured using the ETDRS logMAR chart which acted as the 'gold standard'.


RESULTS
The 95% confidence limits for TRV of RLME acuity data were +/-0.15 logMAR. This figure is consistent with published data on the TRV of acuities measured using five-letter-per-line logMAR charts. The mean difference between RLME and ETDRS acuity data was 0.00 logMAR (95% confidence intervals of +/-0.05 logMAR) indicating that RLME acuities agreed well with those of the ETDRS chart. The chart and its method of use was readily accepted by the local ancillary staff who required only minimal training before acuity measurement could be delegated to them.


CONCLUSIONS
The study demonstrated that the RLME chart is capable of accurate and repeatable acuity measurements. Certain aspects of the design of the RLME chart may be particularly pertinent to the measurement of vision in population-based surveys.
Bourne
R R A
RR
Department of Epidemiology and International Eye Health Institute of Ophthalmology University College London UK. rupert_bourne@hotmail.com
Rosser
D A
DA
Sukudom
P
P
Dineen
B
B
Laidlaw
D A H
DA
Johnson
G J
GJ
Murdoch
I E
IE
D000368:Aged; D004867:Equipment Design; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D014786:Vision Disorders / Q000175:diagnosis*; D015351:Vision Screening / Q000295:instrumentation*; D014792:Visual Acuity