3 Eye Diseases Related to the Cones and Rods — Retinal Impairments
Retina, Normal and Abnormal, Retinitis Pigmentosa (Credit, Rizzo)
Color-Blindness, Retinitis Pigmentosa, Age-Related Macular Degeneration
These 3 retinal eye diseases are different and important.
1. Color-Blindness is Related to Deficiencies of Certain Chemicals in the Cones.
The biochemical deficiencies cause color blindness of red, blue or green, or combinations of these colors. Color blindness is a non-correctable, inherited disease. Color-blindness is related to a genetic defect carried on the X chromosome. There are 2 X chromosomes in females, and only 1 X in males of the total of 46 chromosomes that humans have in each cell of their body. Colorblindness is more common in males than females. Since males have only 1 X chromosome if there is a defect on that X it will show up. Females with 2 X chromosomes, could have an error in 1 X compensated for by a good gene for normal vision on the other X chromosome. A colorblind female would have both X chromosomes with a defective gene for colorblindness.
2. Retinitis pigmentosa is a Disease Characterized by Rod and Cone Degeneration as shown in the microscopic photo above. There is progressive loss of vision with total blindness as rods and cones degenerate. Compare the right and left sides of the photo to see the normal integrity of the retina and the diseased retina.
3. In Age-Related Macular Degeneration (AMD), the Macula (Fovea), which contains the highest concentration of cones and has the greatest visual acuity, shows cell degeneration and progressive loss of central vision over a period of several years.
All the Written Material within Site is Copyrighted 2010 and Owned by Dr. Donald Reinhardt, and this original material is protected legally by this copyright notice and by the Digital Millennium Act. None of this original material may be copied or reproduced without the expressed written consent of the author.
The author is a Freelance Science writer, and is available for specific assignments for those who are interested – by contacting adminstrator@sciencesuperchool.com. Other questions related to this teaching site should be directed to teacher@sciencesuperschool.com.
These 3 retinal eye diseases are different and important.
1. Color-Blindness is Related to Deficiencies of Certain Chemicals in the Cones.
The biochemical deficiencies cause color blindness of red, blue or green, or combinations of these colors. Color blindness is a non-correctable, inherited disease. Color-blindness is related to a genetic defect carried on the X chromosome. There are 2 X chromosomes in females, and only 1 X in males of the total of 46 chromosomes that humans have in each cell of their body. Colorblindness is more common in males than females. Since males have only 1 X chromosome if there is a defect on that X it will show up. Females with 2 X chromosomes, could have an error in 1 X compensated for by a good gene for normal vision on the other X chromosome. A colorblind female would have both X chromosomes with a defective gene for colorblindness.
2. Retinitis pigmentosa is a Disease Characterized by Rod and Cone Degeneration as shown in the microscopic photo above. There is progressive loss of vision with total blindness as rods and cones degenerate. Compare the right and left sides of the photo to see the normal integrity of the retina and the diseased retina.
3. In Age-Related Macular Degeneration (AMD), the Macula (Fovea), which contains the highest concentration of cones and has the greatest visual acuity, shows cell degeneration and progressive loss of central vision over a period of several years.
All the Written Material within Site is Copyrighted 2010 and Owned by Dr. Donald Reinhardt, and this original material is protected legally by this copyright notice and by the Digital Millennium Act. None of this original material may be copied or reproduced without the expressed written consent of the author.
The author is a Freelance Science writer, and is available for specific assignments for those who are interested – by contacting adminstrator@sciencesuperchool.com. Other questions related to this teaching site should be directed to teacher@sciencesuperschool.com.
