POSTS
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
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 image of the structures of the eye. Ophthal- mologists use information gathered from A-Scans before cataract surgery. There are five peaks that make up an A-Scan image. 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
Corneal topography is a topographical map of the cornea. Corneal topography 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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