MANUAL DISTANCE VISION DRUM

A Manual Distance Vision Drum is a tool used by eye care professionals to assess a patient's distance vision, commonly during vision acuity tests. The drum typically displays various optotypes (letters, numbers, or symbols) at different sizes, which are rotated manually to test a person's ability to see at varying distances.

Key Features of a Manual Distance Vision Drum:

1. Optotypes: The drum features printed rows of letters (often Snellen charts), numbers, or other visual symbols used to measure visual acuity. The sizes of the optotypes decrease as you go down each column to test a range of visual capabilities.
2. Rotation Mechanism: The drum is manually rotated to display different sections of the chart without needing to change the chart manually, making the examination process smoother.
3. Distance Measurement: Typically used to test vision at a standard distance (e.g., 20 feet or 6 meters), hence the term "distance vision."
4. Adjustability: Some versions of the drum are adjustable for different angles and heights, allowing flexible usage in various clinical settings.
5. Durability: Made from durable materials like metal or heavy-duty plastic to withstand frequent use in clinical environments. 

Common Uses:

• Visual acuity testing for diagnosing myopia, hyperopia, and other refractive errors.
• Eye exams for driver’s license renewals, school screenings, or occupational testing.