Clinical Blindness – A person visually impaired or having a complete loss of vision; corrective eyewear such as eyeglasses or contact lenses cannot reverse the effect.
“The term "blindness" means central visual acuity of 20/200 or less in the better eye with the use of a correcting lens. An eye which is accompanied by a limitation in the fields of vision such that the widest diameter of the visual field subtends an angle no greater than 20 degrees shall be considered for purposes in this paragraph as having a central visual acuity of 20/200 or less.” (nfb.org)
Visual acuity is the clearness (acuity) of vision. This is especially so with clearly seeing the details of an image.
Partial blindness or legally blind means a person has low vision or very limited vision. There is a multitude of problems that cause blindness; these range from a birth defect to an eye injury occurring, or developing an eye condition resulting in blindness.
Night blindness – condition that makes it difficult to see at night or in other low light conditions.
Color blindness – the inability to accurately detect one color from another; reds, blues, and greens. This affects boys more commonly than girls due to a gene affecting the X chromosome.
Common blindness causes in the US:
Glaucoma – This is a disease affecting the pressure of fluid within the eyeball. The increase of intraocular pressure significantly raises the risk of a person developing glaucoma.
Diabetes - If the blood sugar levels of the disease are not controlled then may result in blindness.
Macular Degeneration – Condition which usually afflicts the elderly. Macular Degeneration – damage to the retina causes a loss of vision in the central portion of the visual.
Amblyopia– Medical term which is also known as “lazy eye” – the eye otherwise seems healthy; however, has a loss of vision with no apparent reason.
Abnormalities or injuries – This could be blindness in one eye due to an injury to the eye.
Cataracts – A milky white film impairing vision. This can cause blindness, requiring the crystalline lens to be replaced to reverse the effects of cataracts.
Poisoning – An example of chemical poisoning is methanol combined with ethanol.
Willful Acts – Barbaric but purposeful harm to the eye can cause blindness.
Treatments can vary depending on the extent or type of sight condition a person has. For a condition that is hereditary, such as LCA (Leber Congenital Amaurosis), gene therapy may be helpful. Damage to the retina’s light receptors from LCA usually begins early on in childhood.
Resources Available to the Blind
Cell Phone – Technology advances now offer turn text, even on photographs, into speech.
T-Mobile – Uses Google’s software download called Android with touch screen technology specifically targeted to accommodate the blind community.
Synthetic Speech and Camera – A high speed resolution camera is connected to a computer and works in conjunction with a speech synthesizer to detect text and read aloud to the blind.
Read to the Blind – Companies will read magazines, newspapers, and information from other medias to those visually impaired