Having trouble seeing full screen?
On macOS, use Chrome in true full screen:
- Enter full screen in Google Chrome.
- In the top menu, click View → uncheck “Always Show Toolbar in Full Screen”.
- This prevents the toolbar from cutting off the bottom of the simulator.
If you still can’t see the whole view, reduce browser zoom (⌘- or Ctrl-).
Some panels may be off-screen. Try full screen or zoom out (⌘- / Ctrl-).
Slit Lamp Simulator
Eye
Switch between the right and left eye. Remember, the patient's right eye is on your left, and vice versa.
From Latin:
- OD – “oculus dexter” → right eye
- OS – “oculus sinister” → left eye
- OU – “oculi uterque” → both eyes
From Latin:
- OD – “oculus dexter” → right eye
- OS – “oculus sinister” → left eye
- OU – “oculi uterque” → both eyes
Fixation
Fixation refers to the specific direction the patient is instructed to look. For example, “Up,” “Down,” or “Look at my ear”. Any change in gaze direction shifts the location of the aerial image. This means that the same examiner hand movements will sample different retinal areas, which is why setting and maintaining a consistent fixation point is essential.
Slit Beam
These settings can be adjusted manually on a real-life slit-lamp with various dials.
Lens presets
This option sets the lens type. Because each lens has its own magnification and optical geometry, it affects both the field of view and the perceived speed at which the retina moves when the lens or slit lamp position is adjusted.
Inferior Retina
Superior Retina
Nasal Retina
Temporal Retina
Anatomical Retina (Upright, Non-Reversed) + Current FOV
Z-Focus
Sharp
Joystick
Keyboard controls
- OD (Right Eye): WASD = Handheld lens (left hand). Arrow keys = Slit-lamp joystick (right hand).
- OS (Left Eye): WASD = Slit-lamp joystick (left hand). Arrow keys = Handheld lens (right hand).
- Tip: The field you see depends on the relative position of lens and slit lamp - move them together in the same direction and the image stays nearly still.
How to practise
- Select OD or OS, then choose a lens type.
- Use WASD and the arrow keys together to simulate coordinated lens and joystick movements.
- Scroll vertically on the main view to adjust Z-focus (drag down = pull back on joystick = sharper focus).
- Observe that when the lens and joystick are moved in the same direction by similar amounts, the retinal field changes very little.
- Use the upright retina window to orient yourself and understand the anatomical region you’re sampling.
- Change the patient’s fixation and repeat the same hand movements to appreciate how the sampled retinal area shifts.
Retina image
If you upload your own retina image, please use a right-eye photo; selecting OS will mirror it automatically.
Pathology Quiz
COMING SOON. Enable quiz mode to examine retinal pathology cases.
Try again
Challenge me
Activating this mode hides the retina labels, anatomical retina window and the Z-focus indicator, requiring you to navigate using only the inverted aerial image. This helps build deeper spatial understanding. You can combine it with Pathology Quiz Mode to further increase difficulty (coming soon).