Saving space: Comparing mini - logMAR with standard logMAR visual acuity.
Purpose
Assessing visual acuity (VA) is the cornerstone of an ophthalmic workup and needs VA charts in a four or six meters space. The objective of this study was to compare the performance of distant VA (DVA) on one meter mini-logMAR (MLM) with a standard six meter logMAR (SLM) chart.


Methods
We developed a MLM chart to be used at 1 m with +1.0 D spectacles, by reducing the SLM chart designed for 6 meters, to 1/6th its size, using AutoCAD version 2014. On an initial cohort, we obtained DVA on the two charts by optometrist trainees, masked to the outcomes on the different tests. We performed regression and checked agreement between the two measurements. Subsequently, on a new cohort, we validated the performance of the MLM.


Results
Of the 56 initial subjects, mean DVA with SLM was 0.44 ± 0.13 and with MLM was 0.45 ± 0.13; mean difference of -0.01 ± 0.02, 95%CI: 0.007 to 0.018; P < 0.0001 on paired t-test. There was a significant correlation: r = 0.99; r2 = 0.98, P < 0.0001. On an average, DVA with MLM was less than a letter worse than with SLM. The regression formula obtained: SLM DVA = -0.1312 + 1.0014 x (MLM DVA). The validation study revealed no significant difference (P = 0.29) between the predicted standard DVA calculated by the regression formula and the actual standard.


Conclusion
We suggest that we can deduce distance logMAR VA from a mini-logMAR chart as devised and used by us. This will take less space, be portable and allow congenial interaction with patients.
['Kauser|Farnaz|F|', 'Amitava|Abadan K|AK|', 'Saxena|Juhi|J|', 'Raza|S Aisha|SA|', 'Masood|Anam|A|', 'Alam|Md Shahid|MS|']
D015331:Cohort Studies D005123:Eye D006801:Humans D015203:Reproducibility of Results D014787:Vision Tests D014792:Visual Acuity
standard logMAR mini-logMAR regression Agreement distant visual acuity