by Dan Roberts
This information is for those who might like to know how much company we have out there. The information in this article was derived from a presentation scheduled for the 2002 ARVO convention, and it is the best estimation of numbers in the United States that I have seen so far. For the most recent figures on numbers of people with blindness and visual impairment worldwide, see Blindness and Visual Impairment Rates Have Fallen.
Data for this report was gathered from the major eye disease prevalence studies, to include the Baltimore Eye Survey, the Beaver Dam Eye Study, the Salisbury Eye Evaluation Project, Proyecto Ver, the Melbourne Visual Impairment Project, the Blue Mountains Eye Study, the Rotterdam Study, and the Barbados Eye Study. The researchers were from Wilmer Eye Institute, Johns Hopkins University, and 2ORC Macro International.
RESULTS:
- Number of people who are centrally blind in both eyes = 361,600 (Expected to rise to 501,600 (41%) by 2020, due to the aging of the population.)
- Number of people with geographic atrophy (i.e. dry MD) = 756,200
- Number of people with neovascular (wet) MD = 105,190
- Number of people with large drusen (>125 microns) in one eye = 4,910,000
- Number of people with large drusen (>125 microns) in both eyes = 2,341,800
- Total number of people in the U.S. affected by macular degeneration = 8,474,790
This total is higher than most previous estimates, further dramatizing the importance of research, information-gathering, and support for those who are part of the MD population.
For those who would like a breakdown of all major inherited retinal diseases, here is a report by Stephen P. Daiger, PhD., Professor of Human Genetics Center, School of Public Health and Dept. of Ophthalmology and Visual Science, The University of Texas – Houston. He writes:
One question that comes up occasionally is the numbers of people with various forms of inherited retinal disease (known as the “prevalence”). This is a summary based on published surveys, clinical reports and educated guesses.
The numbers are based on the American population, and surveys in Europe, but they also apply throughout the world, because these conditions affect all groups of people roughly the same.
Please don’t take the numbers (or the categories) very seriously. There is no way to know exact numbers, and most of the estimates are based on small surveys. Also, please note the distinction between the forms of retinal degeneration, which are clearly inherited (such as retinitis pigmentosa and juvenile forms of macular degeneration), and the most common form, age-related macular degeneration, which is influenced by genes, but is not inherited in any simple way. Inherited forms of retinal disease affect approximately 200,000 Americans, whereas age-related macular degeneration affects 5 million to 10 million Americans. The following table applies to inherited forms only.
The table starts with broad categories, and then shows a break down of the categories. The first number shown is the percentage of the total, and the second is the expected number in an American population of about 280 million.
| A. Broad categories | ||
| 1. Retinitis pigmentosa | 40% | 80,000 |
| 2. Usher syndrome | 10% | 20,000 |
| 3. Cone-rod dystrophy | 10% | 20,000 |
| 4. Inherited macular degeneration | 10% | 20,000 |
| 5. Chorioretinal degeneration | 5% | 10,000 |
| 6. Leber congenital amaurosis | 5% | 10,000 |
| 7. Congenital stationary night blindness | 5% | 10,000 |
| 8. Retinoschesis | 3% | 6,000 |
| 9. Choroideremia | 2% | 4,000 |
| 10. Other inherited retinopathies | 10% | 20,000 |
| TOTALS | 100% | 200,000 |
| B. Sub-categories | ||
| 1. Retinitis pigmentosa (40% of total) | ||
| a. autosomal dominant | 10% | 20,000 |
| b. autosomal recessive | 8% | 16,000 |
| c. X-linked | 6% | 12,000 |
| d. single case or unknown | 16% | 32,000 |
| 2. Usher syndrome (10%) — nearly all recessive | 10% | 20,000 |
| 3. Cone-rod (10%) | ||
| a. autosomal dominant | 2% | 4,000 |
| b. autosomal recessive | 2% | 4,000 |
| c. other/unknown | 6% | 12,000 |
| 4. Inherited macular degeneration. (10%) | ||
| a. autosomal dominant | 2% | 4,000 |
| b. autosomal recessive | 1% | 2,000 |
| c. other/unknown | 7% | 14,000 |
| 5. Chorioretinal degeneration (5%) — nearly all recessive | 5% | 10,000 |
| 6. Leber congenital amaurosis (5%) — nearly all recessive | 5% | 10,000 |
| 7. Congenital stationary n.b. (5%) | ||
| a. autosomal dominant | 1% | 2,000 |
| b. autosomal recessive | 1% | 2,000 |
| c. X-linked | 1% | 2,000 |
| d. other/unknown | 2% | 4,000 |
| 8. Retinoschesis (3%) — nearly all X-linked | 3% | 6,000 |
| 9. Choroideremia (2%) — nearly all X-linked | 2% | 4,000 |
| 10. Other inherited retinopathies (10%) — unknown mixture | 10% | 20,000 |
| TOTALS | 100% | 200,000 |
| A. Broad categories | ||
| 1. Retinitis pigmentosa | 40% | 80,000 |
| 2. Usher syndrome | 10% | 20,000 |
| 3. Cone-rod dystrophy | 10% | 20,000 |
| 4. Inherited macular degeneration | 10% | 20,000 |
| 5. Chorioretinal degeneration | 5% | 10,000 |
| 6. Leber congenital amaurosis | 5% | 10,000 |
| 7. Congenital stationary night blindness | 5% | 10,000 |
| 8. Retinoschesis | 3% | 6,000 |
| 9. Choroideremia | 2% | 4,000 |
| 10. Other inherited retinopathies | 10% | 20,000 |
| TOTALS | 100% | 200,000 |
| B. Sub-categories | ||
| 1. Retinitis pigmentosa (40% of total) | ||
| a. autosomal dominant | 10% | 20,000 |
| b. autosomal recessive | 8% | 16,000 |
| c. X-linked | 6% | 12,000 |
| d. single case or unknown | 16% | 32,000 |
| 2. Usher syndrome (10%) — nearly all recessive | 10% | 20,000 |
| 3. Cone-rod dystrophy (10%) | ||
| a. autosomal dominant | 2% | 4,000 |
| b. autosomal recessive | 2% | 4,000 |
| c. other/unknown | 6% | 12,000 |
| 4. Inherited macular degeneration. (10%) | ||
| a. autosomal dominant | 2% | 4,000 |
| b. autosomal recessive | 1% | 2,000 |
| c. other/unknown | 7% | 14,000 |
| 5. Chorioretinal degeneration (5%) — nearly all recessive | 5% | 10,000 |
| 6. Leber congenital amaurosis (5%) — nearly all recessive | 5% | 10,000 |
| 7. Congenital n.b. (5%) | ||
| a. autosomal dominant | 1% | 2,000 |
| b. autosomal recessive | 1% | 2,000 |
| c. X-linked | 1% | 2,000 |
| d. other/unknown | 2% | 4,000 |
| 8. Retinoschesis (3%) — nearly all X-linked | 3% | 6,000 |
| 9. Choroideremia (2%) — nearly all X-linked | 2% | 4,000 |
| 10. Other inherited retinopathies (10%) — unknown mixture | 10% | 20,000 |
| TOTALS | 100% | 200,000 |