fundic photography / retinal imaging with a smartphone
Taking photographs of the fundus is now accessible to all veterinary surgeons with advances in smartphone technology.
The following text describes the technique to mimic close direct ophthalmoscopy.
The ideal camera app allows for continued illumination (torch mode), touch focus and exposure
For iPhones download the 'camera+' app from itunes
Android users can use 'DSLR Camera' app*
(*some of the settings and functionality described below will not be available)
The ideal smartphone has an LED light close to the camera lens to mimic close direct ophthalmoscopy
Set up the app options in the menu:
- Maximum image resolution for image capture
- 'Volume snap' switched on - this allows you to take an image by pressing the + volume button on the side of the phone
- Geotagging switched on
- 'Live exposure' switched on this will display your ISO and shutter speed
- Autosave and iCloud sync allow for automated backup of the photos
- Remove your phone case. You will need to get very close to the eye
- Keep your phone warm, otherwise the lens will steam up when close to the eye
- Tear two pieces of adhesive medicine bottle label or six or more pieces of micropore tape and place over the LED flash
- You need to have the LED light switched on torch mode within the flash settings. The LED is very bright, hence the sticky label filter to diffuse and dim the light.
- Focus and exposure can be split by separating two fingers on the centre of the screen. This is very useful for hyper-reflective fundi
- You can manually reduce the exposure compensation (+/-EV) settings at the bottom of the screen
- The app has the ability to manually change the focus, shutter speed, ISO and white balance if you think that the auto function is not sufficient
- In 'full manual mode' you can set the focus to infinity which stops the camera 'hunting' for the correct focus point