Optonet Vision Unit Documentation

Please note that this User Guide is being currently updated; new sections will be added shortly.

  1. QuickStart Guide (in 5 steps)
    1. Step 1. Choosing Hardware
    2. Step 2. Installation and Calibration
    3. Step 3. Menus
    4. Step 4. Control of Menus and Charts
    5. Step 5. Customise Sequences of Charts
    6. How to check if my charts are well calibrated?
  2. Home-based Vision Training (Orthoptics)
    1. Patient Selection
    2. Calendar
    3. Daily Exercise Program
    4. Parameters
    5. Comments
    6. Login Credentials for the patient
    7. Attaching documents
    8. Save Therapy
    9. Access as Patient
    10. Remote monitoring of patient progress
    11. Management of Patient’s Access
  3. Virtual Eye Clinic
  4. Visual Acuity
    1. logMAR VA
    2. Logarithmic Notation
    3. VA Rating (VAR) or VA Score (VAS)
    4. VA Tools Menu
      1. Selecting Rows and VA Values.
      2. Visual Acuity Range
      3. Bi-Chrome Function
      4. Isolated Optotypes (Rows, Columns and Letters)
      5. Contrast
      6. Randomizing the order of optotypes
      7. Vanishing Optotypes
      8. Intermediate Steps
      9. Tablet as a remote controller for VA
    5. VA Optotypes
      1. Sloan letters
      2. British Letters
      3. Numbers
      4. Landolt Optotype "C"
      5. E of Snellen
    6. References Visual Acuity
    7. Paediatric Visual Acuity
      1. Test of “Broken Glasses”
      2. Symmetrical Optotype
      3. References Paediatric Visual Acuity
    8. Automated Visual Acuity Testing
      1. ETDRS, Bailey-Lovie, Snellen E, Numbers and Landolt C
      2. Symmetrical Letter Chart
      3. Broken Glasses Chart
      4. References Automated VA Testing
      5. VA Testing Protocol > 8 years old (printable document)
      6. VA Testing Protocol ≤ 8 years old (printable document)
  5. Setup
    1. Colour Calibration

4.4.7.Vanishing Optotypes #

The vision unit incorporates a novel feature that allows converting conventional optotypes into vanishing optotypes by clicking on an tools menu icon or typing “V” on the keyboard.

 

 

The Vanishing optotypes are formed by a central black trace (which gets smaller for smaller optotypes), surrounded by a white border on each side of half thickness. The letters thus created are displayed in front of a gray background, so that the average luminance of the letter is identical to the luminance of the background. In this way, when a letter is blurred it disappears on the gray background; hence the name “vanishing” optotypes.

Using vanishing optotypes allows more sensitive detection of foveal vision loss than conventional optotypes.  This is because conventional optotypes, made with black strokes on a white background, may still be distinguished, even when they are blurred or fuzzy.

Recent studies4 have shown that measuring acuity with these new optotypes provides earlier detection of age-related macular degeneration (AMD). They are also significantly more sensitive in the follow-up of visual impairment in AMD.

« Randomizing the order of optotypesIntermediate Steps »
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