• Optotype: Select from a range of standard optotypes.
• Alphabet: The available options are dependent on the OPTOTYPE selected above. SnellenU and SloanU use a wider selection of letters, but letters may not be of equal readability. BS4724.3 and ETDRS are standard alphabets using fewer letters, but with more equal readability. Letters can be shuffled to prevent learning and increase repeatability - see below

• Notation: Sets the notation type on the VA label on each chart line. Regardless of notation or optotype, WolfChart uses the standard logMAR array of subtenses (0.501, 0.631, 0.794, 1, 1.259, 1.585, 2, 2.512, 3.162, 3.981, 5.012, 6.31, 7.943, 10, 12.59, 15.85, 20) with each 3 lines doubling the subtense. Notation and Numerator express these subtenses as your preferred VA value.You're an optometrist; one or more of these will be familiar to you. logMAR is explained here https://en.wikipedia.org/wiki/LogMAR_chart.
• Numerator: Sets the numerator of the fraction notation types only; if Notation is set to logMar,DecimalV or VAS, this setting makes no difference.
  "Standard" is either 6 or 20 depending whether Notation is set to Metres or Feet above. VA labels will display as either 6/ or 20/ regardless of the value in Distance.
  "Actual" is the value entered in Distance (see below) rounded to the nearest 0.1m or 0.5ft. The VA labels will show this rounded numerator, with a ! instead of a /, and a proportionally adjusted denominator. Please note that it is not advisable to use Standard if the Distance varies a large amount from 6000mm, say outside 5500-6500mm. The numerator should be the tested distance or near to it.

The two CALIBRATION values are the only values that influence the size of the letters. The RECORDING values above only change the VA labels on the letter chart lines, and have no bearing on the letters themselves.

• Distance: Enter the distance from the patient's eye to the letter chart in mm. Eg 6m is 6000mm. Even if you work in feet (see Notation above), you must enter the Distance in mm. If using a mirror to double the test distance, measure BOTH from the patient's eye to the mirror AND from the mirror to the display and ADD the two distances (and don't forget to check the Mirrored/Direct setting - see below). If you are using Notation value of "Feet", Numerator will be converted to the nearest foot, or to 20 depending on the value in Numerator.
• Length of the line below: Calibrates the chart. WolfChart does not need to know anything about the screen you are using; it just needs the length of this green line as it is displayed. Measure the length of the green line as accurately as possible. On a touch screen this is tricky, but you'll work it out. You will need to re-check this value if you change display hardware, graphics adapter settings, or if you turn your display from landscape to portrait or vice versa. Take particular care here if you are using extended display from a computer as pixel density may be different between the computer screen and the external display.

• Sort: Unless the display is very large, the letter chart will display in pages - see SHORTCUTS below. Here you can select whether to display the page of the smallest or largest lines first. If French, you have a Monoyer option.
• Mirrored/Direct: Select "Direct" if WolfChart is to be viewed directly, otherwise select "Mirrored" and the letters and lines will be reversed, but the labels not. If changing this setting, don't forget to set the Distance (see above) accordingly.
• Lines/page: Should be self explanatory.
• Scroll style: Scroll the letter chart up and down page-by-page or by the largest line on each page.
• Shuffle style: Shuffle only the visible letters of each line (small), or all possible letters of the optotype (big). Shuffle is a toggle - it's either on or off - but each shuffle is new and is indicated by the shuffle button lit green. If you want to shuffle continuously, just hit shuffle twice. Big shuffle works best if your display is small and many lines are shorter than 5 characters, otherwise it's just personal preference.
• Optotype colour: Defaults to solid black. Enter any valid rgba string or use the preset buttons for common values.
• Background colour: Defaults to solid white. Enter any valid rgba string or use the preset button/s. If a Vanishing optotype is selected, this field is disabled.
• Duochrome: Choose a duochrome combination. All pairs are luminance-matched.

Use these fields to specify keyboard shortcuts for operating WolfChart. All these shortcuts have a corresponding sidebar button.
Certain keys are reserved and you will be alerted not to use them if you try.

• Page Up/Dn/Left/Right: Page Up, Down, Left and Right are already mapped to the arrows on your keyboard, and the arrow buttons on screen. If your controller doesn't have arrow keys, add custom shortcuts here, eg u,n,g and k respectively
  
• Shuffle:: Toggles shuffle of the letters. See OPTIONS above.
• Duochrome:: Toggles your chosen duochrome background on V charts.
• Cycle Mask:: Cycles through masking modes. If using this shortcut or the button, the first mask is up the top, and the navigation buttons then move the mask around.