Tumbling E Chart 2.7.2

This application emphasizes the principle that prevention is preferable to treatment. Designed for children over the age of six, parents with young children, and healthcare professionals, it features optically accurate tumbling E chart optotypes to facilitate precise measurement of distant visual acuity. This can aid in early detection of nearsightedness or myopia, enabling timely preventative interventions and professional consultation to prevent the progression from pseudomyopia to true myopia, or to halt worsening of existing nearsightedness.

Predefined Testing Distances include:

• 6, 5, 4, 3, and 2 meters
• 20, 15, 12, 10, and 6 feet

At a distance of exactly 6 meters from the subject, the optotypes on the 6/6 line (Decimal 1.0 or LogMAR 0.0) are designed to subtend five minutes of arc. Accordingly, these optotypes should measure approximately 8.73 mm in height if properly scaled. The largest optotypes on the topmost line (corresponding to 6/60 Snellen fraction, Decimal 0.1, or LogMAR 1.0) should then measure approximately 87.3 mm in height. Similarly, at exactly 20 feet (approximately 6.096 meters), the topmost optotypes should be about 88.7 mm tall.

Possible testing scenarios include:

1. Doctor and patient assessment
2. Self-diagnosis using a mirror
3. Self-diagnosis with Bluetooth keyboard
4. Self-diagnosis within arm’s reach

Recognized notations within the app encompass:

• Decimal (e.g., 0.50)
• Fraction (e.g., 20/40)
• LogMAR (e.g., 0.30)
• Other fractions such as 5/10 and 6/12
• MAR (e.g., 2)
• VAS or VAR (e.g., 85)

The application offers two testing modes:

1. Autoplay
2. Manual

In autoplay mode, the app calculates the test score automatically. For LogMAR notation, the score equals the LogMAR value of the best line read plus 0.02 times the number of missed optotypes—up to a maximum of three misses. For VAS notation, the score inverses the LogMAR scale using VAS=100–50×logMAR for more intuitive interpretation since higher scores indicate better visual acuity. For other notations such as fractional formats, the score reflects the value of the best line read minus any missed optotypes, with a maximum of two misses allowed.

The feature “Play Interval Until Next Optotype” defaults to none but can be adjusted in seconds—2, 4, 6, 8, or 10. If the patient cannot recognize an optotype within this interval, it is registered as a miss.

Enabling “Record Scores” in settings allows users to monitor visual acuity trends over time across multiple testers. Here, visual acuity scores are displayed with color coding: scores of 100 in blue serve as the reference standard; scores above 100 in green suggest no myopia; scores below 100 in red may indicate myopia.

The process for assessing myopia typically involves initial checks of distant visual acuity through a standardized chart—any decline in visual accuracy can be indicative of myopic development.

Disclaimer: While this application can serve as a convenient tool for measuring visual acuity analogously to print tumbling E charts, it does not replace comprehensive examinations conducted by qualified eye care professionals. Regular visits to an optometrist or ophthalmologist are recommended for thorough assessment and early management of any detected vision issues.