STUDIES
Ophthalmic Imaging
Slit-Lamp/Anterior Segment Photography
The five types of slit-lamp illumination
| Illumination | Meaning |
| Direct | Illumination is directly on area of interest |
| Indirect | Illumination is on another structure than the structure of interest |
| Diffuse | Illuminates entire area (nonspecific) |
| Retroillumination | Illuminates structure behind structure of interest |
| Tangential | Illuminates area across the surface of a structure |
Fundus Photography
http://en.wikipedia.org /wiki/Fundus_(eye)
The above image is an example of a fundus photograph. When taking a fundus photo the eye must be dilated and the lens clean. The fundus photo of the retina allow the practitioner to identify pathology on the retina such as drusen, neovascularization, and cotton wool spots.
The funds camera can also be used to create external photos of the eye.
External Photography
External photography is a photograph of the external eye. The area of interest must be lighted just right. A picture with a shadow on the area of interest will not be useful. Also, a reflection of the camera flash on the area of interest will not be useful.
Diagnostic/Standardized A-Scan
A-scans use ultrasounds to make a one dimensional image of the structures of the eye. Ophthalmologists use information gathered from A-Scans before cataract surgery.
http://www.sceyes.com/Home /AdvancedTechnology.aspx
The first peak represents the cornea. The second peak represents the front of the lens. The third peak represents the back of the lens. The fourth peak represents the retina. The fifth peak represents the sclera.
Corneal Topography
http://greenfieldgeography.wikispaces.com /IGCSE+and+GCSE+Geography+Skills+(Paper+2)
The image above is a topographical map. The closer the lines are the steeper the slope of the mountain. The same is true for corneal topography.
http://www.siliconehydrogels.org /in_the_practice/oct_07.asp
The above image is a corneal topography. This helps the ophthalmologist know the best location to make an incision. You will notice that this image also has color. The “cooler” the color the the flatter the surface.
Scanning Laser Tests for Glaucoma/Retina
Scanning laser tests, such as the OCT, are used to monitor glaucoma and retina problems. OCTs can return images of macular thickness. They can also return images of the optic nerve which can indicate thinning of the optic disk and the disk to cup ratios which are important in monitoring glaucoma.
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