MOST COMMON DISEASES
These links take you off-site. Here are the codes to where:
AAV = All About Vision
AFB = American Foundation for the Blind
AOA = American Optometric Association
APH = American Printing House for the Blind
CRF = Cornea Research Foundation
FB = Fighting Blindness (Irish)
FFB = Foundation Fighting Blindness
MAYO = Mayo Clinic
MED = Medline Plus (NIH)
NIH = National Institutes of Health
NORD = National Organization for Rare Disorders
RNIB = Royal National Institute of Blind People (British)
SG = Support Group or focused Specialty Group
UofA = The University of Arizona
Achromatopsia NIH FB SG
Albinism NIH VisionAware SG
Amblyopia NIH SG
Aniridia NIH SG
Anophthalmia and Microphthalmia NIH
Aphakia, Congenital NIH UofA
Astigmatism NIH AOA MAYO
Bardet-Biedl Syndrome NIH NORD SG
Best Disease RNIB FB
Blue-Cone Monochromacy FFB Orphanet
Cataracts NIH MAYO
CHARGE Syndrome: see also Coloboma. NIH
Charles Bonnet syndrome RNIB AFB SG
Choroideremia FB SG
Coloboma: see also CHARGE Syndrome NIH
Color Blindness NIH
Corneal Disease NIH CRF
Corneal Dystrophy, Fuchs' MAYO SG SG SG
Cortical Visual Impairment Neurological AFB APH
Dry Eye Syndrome NIH MAYO
Dysplasia: see Hypoplasia
Dystrophy (Cone-Rod) NIH FB
Exudative Vitreoretinopathy (Familial) NIH OrphaNet ASRS SG
Farsightedness: see Hyperopia
Floaters and Spots NIH MAYO
Glaucoma NIH SG
Hemianopia NIH SG
Hyperopia (Farsightedness) NIH
Hypopigmentation (see also Albinism) SG
Hypoplasia (Optic Nerve) NIH SG SG
Keratoconus CRF SG
Keratopathy (Bullous) CRF
Laurence-Moon-Bardet-Biedl Syndrome NIH SG
Leber Congenital Amaurosis FB
Leber’s Hereditary Optic Neuropathy (LHON) NIH FB SG
Low Vision NIH SG
Macular Degeneration (age related) NIH FB SG
Macular Edema, Diabetic NIH MAYO
Macular Pucker NIH
Macular Hole NIH
Malattia Leventinese NIH FFB
Marfan Syndrome NIH SG
Microphthalmia: see Anophthalmia
Myopia (Nearsightedness) NIH AOA
Nystagmus AOA AAV SG
Oguchi Disease NIH FFB
Refsum NIH SG
Retinal Detachment NIH FB SG
Retinitis Pigmentosa NIH FB
Retinoblastoma NIH SG
Retinopathy of Prematurity NIH
Retinopathy (Diabetic) AFB NIH MAYO
Retinoschisis, Juvenile X-linked FB
Retrolental Fibroplasia: see Retinopathy of Prematurity.
Rod-Cone Dystrophy: see Dystrophy
Stargardt Disease (Stargardt Juvenile Macular Dystrophy) NIH FB
Strabismus (see also Amblyopia) NIH Medline SG
Sturge-Weber Syndrome NIH SG
Trachoma NIH MAYO SG
Usher Syndrome NIH FB SG
Uveitis NIH SG
Vitelliform Macular Dystrophy: see Best Disease.
PARTS IS PARTS
The cornea is a transparent dome-shaped tissue that forms the front part of your eye. It functions as a window and allows light to enter your eye. It also begins the process of focusing light rays that allow you to see words and images clearly. The cornea does not contain any blood vessels, but instead contains nerve endings that make it extremely sensitive. That is why a scratch or a loose eyelash is so painful.
Aqueous humor is a clear, watery fluid contained in a chamber behind the cornea that helps bring nutrients to the ocular tissue. It is made behind the lens and flows to the front of the eye, where it is drained by a tissue called the trabecular meshwork. Problems with the flow of this fluid can lead to problems with the pressure inside the eye.
The sclera is a tough white outer coating of fibrous tissue that covers your entire eyeball (all the way around) except for the cornea. The muscles that move the eye are attached to the sclera. The name sclera comes from the Greek word "skleros," which means "hard."
THE IRIS AND PUPIL
The iris is a tissue inside the eye that has a hole in the center called the pupil. The iris contains muscles that allow the pupil to become larger (open up or dilate) and smaller (close up or constrict). The iris regulates the amount of light that enters your eye by adjusting the size of the pupil opening. In bright light, the iris closes (or constricts) and makes the pupil opening smaller to restrict the amount of light that enters your eye.In dim light, the iris opens (or dilates) and makes the pupil opening larger to increase the amount of light that enters your eye. In addition, it is the iris that determines your eye color. People with brown eyes have heavily pigmented irises, while people with blue or lighter-colored eyes have irises with less pigment. Therefore, people with lighter-colored eyes should wear sunglasses outdoors, especially during the summer. According to Prevent Blindness America, extended exposure to ultraviolet (UV) light (such as sunlight) has been linked with cataracts and macular degeneration.
The choroid is a dark brown membrane that is rich with blood vessels, located between the sclera and the retina. It supplies blood and nutrients to the retina and nourishes all of the other structures within the eye.
The vitreous is the jelly-like substance that fills the inside of the back part of the eye. Over time, the vitreous becomes more liquid and can detach from the back part of the eye, which can create "floaters." If you notice new floaters or flashing lights, it is important to see an eye doctor, because a detached vitreous can cause a hole (a condition called a "macular hole") to develop in the retina.
RETINA AND OPTIC NERVE
The retina is the light-sensitive tissue that lines the inside surface of the eye, much like wallpaper. Cells in the retina convert incoming light into electrical impulses. These electrical impulses are carried by the optic nerve (which resembles your television cable) to the brain, which finally interprets them as visual images.
The macula is the small sensitive area in the center of the retina that provides clear central vision. The fovea is located in the center of the macula and provides the sharpest detail vision.
The lens is composed of transparent, flexible tissue and is located directly behind the iris and the pupil. It is the second part of your eye, after the cornea, that helps to focus light and images on your retina. Because the lens is flexible and elastic, it can change its curved shape to focus on objects and people that are either nearby or at a distance. A more rounded lens can focus on near objects, a more elongated (or stretched) lens can focus on objects that are far away.
The ciliary muscles, which are part of the ciliary body, are attached to the lens and contract or release to change the lens shape and curvature. The lens becomes more rounded to focus on near objects. Over time, the lens loses some of its elasticity and therefore loses some of its ability to focus on near objects. This is called "presbyopia" and explains why people need reading glasses as they become older.
The National Library of Medicine is a division of the National Institutes of Health. They have a database of more than 750 of the most common genetic diseases on a page they call Genetics Home Reference. It provides consumer-friendly information about the effects of genetic variations on human health. Use their search box function at the top of their page.
JUST TO REMIND US:
Legal Blindness is a level of visual impairment that has been defined by law to determine eligibility for benefits. It refers to central visual acuity of 20/200 or less in the better eye with the best possible correction, or a visual field of 20 degrees or less.