Corneal topography, also known as photokeratoscopy or videokeratography, is a non-invasive medical imaging technique for mapping the surface curvature of the cornea, the outer structure of the eye. Since the cornea is normally responsible for some 70% of the eye's refractive power, its topography is of critical importance in determining the quality of vision.
The three-dimensional map is therefore a valuable aid to the examining ophthalmologist or optometrist and can assist in the diagnosis and treatment of a number of conditions; in planning refractive surgery such as LASIK and evaluation of its results; or in assessing the fit of contact lenses. A development of keratoscopy, corneal topography extends the measurement range from the four points a few millimeters apart that is offered by keratometry to a grid of thousands of points covering the entire cornea. The procedure is carried out in seconds and is completely painless.
Visual Field Testing
A visual field test measures how much 'side' vision you have. It is a straightforward test, painless, and does not involve eye drops. Essentially lights are flashed on, and you have to press a button whenever you see the light. Your head is kept still and you have to place your chin on a chin rest. The lights are bright or dim at different stages of the test. Some of the flashes are purely to check you are concentrating.
Each eye is tested separately and the entire test takes 15-45 minutes. Your optometrist may ask only for a driving licence visual field test, which takes 5-10 minutes. If you have just asked for a driving test or the clinic doctor advised you have one, you will be informed of the result by the clinic doctor, in writing, in a few weeks.
Normally the test is carried out by a computerised machine, called a Humphrey. Occasionally the manual test has to be used, a Goldman. For each test you have to look at a central point then press a buzzer each time you see the light.
Digital Retinal Imaging & OCT Scans
We use cutting-edge digital imaging technology to assess your eyes. Many eye diseases, if detected at an early stage, can be treated successfully without total loss of vision. Your retinal Images will be stored electronically. This gives the eye doctor a permanent record of the condition and state of your retina.
This is very important in assisting your Optometrist to detect and measure any changes to your retina each time you get your eyes examined, as many eye conditions, such as glaucoma, diabetic retinopathy and macular degeneration are diagnosed by detecting changes over time.
The advantages of digital imaging include:
- Quick, safe, non-invasive and painless
- Provides detailed images of your retina and sub-surface of your eyes
- Provides instant, direct imaging of the form and structure of eye tissue
- Image resolution is extremely high quality
- Uses eye-safe near-infra-red light
- No patient prep required
The Diopsys® NOVA-VEP
Visual Evoked Potential (VEP) Tests
VEP measures the electrical activity in the vision system. When light from an image enters your eye, it is converted into electrical energy at the retina and travels through the optic nerve to the visual cortex of the brain which processes vision. The Diopsys® NOVA-VEP test measures the strength of the signal reaching your visual cortex and how fast it gets there.
Electroretinogram (ERG) Tests
ERG measures the function of your retina – the light-sensitive layer at the back of your eye. When light from an image enters the eye, it is converted into electrical energy by specialized cells in the retina. These cells send electrical impulses through the optic nerve to the brain where the image is processed. The Diopsys® NOVA-ERG test records how well the cells of the retina are conveying electrical impulses within the eye.
Download this brochure and learn more about the Diopsys® NOVA-VEP.