Information for Patients
The retina is a layer of tissue in the back of your eye that senses light and sends images to your brain. In the center of this nerve tissue is the macula. It provides the sharp, central vision needed for reading, driving and seeing fine detail.
Retinal disorders affect this vital tissue. They can affect your vision, and some can be serious enough to cause blindness. Examples are
- Macular degeneration - a disease that destroys your sharp, central vision
- Diabetic eye disease
- Retinal detachment - a medical emergency, when the retina is pulled away from the back of the eye
- Retinoblastoma - cancer of the retina. It is most common in young children.
- Macular pucker - scar tissue on the macula
- Macular hole - a small break in the macula that usually happens to people over 60
- Floaters - cobwebs or specks in your field of vision
NIH: National Eye Institute
General Equivalence Map Definitions
The ICD-10 and ICD-9 GEMs are used to facilitate linking between the diagnosis codes in ICD-9-CM and the new ICD-10-CM code set. The GEMs are the raw material from which providers, health information vendors and payers can derive specific applied mappings to meet their needs.
- Approximate Flag - The approximate flag is on, indicating that the relationship between the code in the source system and the code in the target system is an approximate equivalent.
- No Map Flag - The no map flag indicates that a code in the source system is not linked to any code in the target system.
- Combination Flag - The combination flag indicates that more than one code in the target system is required to satisfy the full equivalent meaning of a code in the source system.