Auto Assessment

Auto-Play

In Auto-play, the app calculates the score. And you can save scores of each assessment for yourself or other test subjects.

Recording and Reviewing Scores

  • By enabling “Record Scores” in Settings, you can track the progression of your visual acuity over time.

Time limit for recognizing optotypes

  • By default, the "Play Interval Until Next Optotype" setting is None.
    Available intervals (in seconds): 2, 4, 6, 8, and 10.
  • If the test subject fails to recognize the optotype within the time limit, it is counted as a miss.

Score Review Indicators

  • A score of 100 in blue indicates the reference standard.
  • Scores above 100 in green suggest no myopia.
  • Scores below 100 in red may indicate possible myopia.

 

LogMAR, MAR and VAS notation 

  • The assessment ends when a row has at least one optotype missed.
  • The best row read is the row with the smallest optotypes that the test subject can accurately identify.
  • The best row missed is the next row with smaller optotypes, where the test subject misses at least one optotype but reads at least one.

Scoring Formula

- The score is calculated using the formula:

(LogMAR value of the best row missed) + 0.02 × (number of optotypes missed)

Alternatively, the equivalent formula is:

(LogMAR value of the best row read) - 0.02 × (number of optotypes read in the next row)

(Each row contains 5 optotypes.)

Hints:

  • Due to the limited width of smartphones, the Eye Charts app shows 1 or 3 optotypes of top rows with large optotypes at a time, however, the app loops through 5 optotypes of the same row. During auto-play, the test subject should read the middle optotype being displayed.

For VAS notation, the score is an inversion of the LogMAR scale, based on formula VAS=100-50xlogMAR. It is more intuitive since higher values indicate better visual acuity.

For MAR notation, the score is 10^(LogMAR).

Other notations

  1. The assessment ends when more than 50% of optotypes in a row are missed, such as 3 out of 5.
  2. The best row read is the row with the smallest optotypes where the test subject can correctly identify more than 50%, for example, 3 out of 5.
  3. The score is (LogMAR value of the best row read) + 0.02 x (number of optotypes missed)

References: