Legal blindness in America
What is legal blindness?
Legal blindness is a term used to describe a level of visual impairment that is recognized by law to determine eligibility for certain benefits and services.
The specific criteria for legal blindness may vary from one jurisdiction to another, but generally, it refers to a visual acuity and/or visual field that is severely impaired.
In most countries, legal blindness is defined as having visual acuity of 20/200 or worse in the better eye, even with the use of corrective lenses. Visual acuity refers to the clarity or sharpness of vision, and 20/200 means that a person can see at 20 feet what a person with normal vision can see at 200 feet. Legal blindness can also be defined based on the visual field, which refers to the total area that can be seen without moving the eyes from side to side or up and down. If the visual field is restricted to 20 degrees or less in the better eye, it may also qualify as legal blindness.
Legal blindness in America:
Approximately 12 million adults aged 40 and above in the United States are estimated to have irreversible vision loss, with over 1 million individuals classified as blind. Due to factors like the rising prevalence of diabetes and other chronic diseases, as well as the ageing population, it is projected that the number of blind individuals will reach 8.96 million by 2050. Additionally, the Center for Disease Control and Prevention (CDC) reports that nearly 3% of children under 18 years old are blind or visually impaired.
The World Health Organization (WHO) distinguishes between two levels of visual impairment: Low Vision and Blindness, as outlined in the WHO ICD-10 table. Low vision encompasses categories 1 and 2, while blindness encompasses categories 3, 4, and 5.
Vision disability ranks among the top 10 disabilities for adults aged 18 and older and is one of the most prevalent disabling conditions among children, according to the CDC. Legal blindness, as defined by the Social Security Act (SSA), is referred to as statutory or legal blindness.
In 2006, the SSA updated the definition of legal blindness, which took effect in 2007. The new definition still considers the best corrected visual acuity (VA) of 20/200 or lower in the better-seeing eye, as well as a visual field (VF) limitation where the widest diameter of the visual field subtends an angle no greater than 20 degrees. However, the rules regarding how to measure VA and VF were modified.
Regarding visual acuity testing, the criteria have changed to accommodate the newer test charts that include lines measuring visual acuity between 20/100 and 20/200. Under the updated criteria, if a person’s visual acuity is assessed using one of these charts and they cannot read any letters on the 20/100 line, they will qualify as legally blind with a visual acuity of 20/200 or lower.
For example, if a person’s best-corrected visual acuity for distance in the better eye measures 20/160 using an ETDRS chart, they would now be classified as legally blind. It’s important to note that regardless of the test chart used, a person will not be considered legally blind if they can read at least one letter on the 20/100 line. Pinhole acuities or automated refraction acuities are not used to determine legal blindness by the Social Security Administration.
For visual field testing, the extent of visual field loss can be measured using either automated static threshold perimetry (such as Humphrey Field Analyzer 30-2 and 24-2 and Octopus 32) or manual kinetic perimetry (using Goldmann III-4e stimulus). Visual field screening tests like confrontation tests, tangent screen tests, or automated static screening tests are not used by the Social Security Administration to determine legal blindness.
Eligibility of various services in legal blindness
Patients who meet the legal blindness definition should receive a Certificate of Legal Blindness from their optometrist. They should also be informed about the various opportunities and benefits available to them. A Certificate of Legal Blindness is used by agencies to determine eligibility for vocational training, rehabilitation, schooling, Social Security disability benefits, IRS tax exemption, state agency services, housing, utilities, telephone services, as well as services like audible books and handicap plates or placards.
Reference : May/June 2023 edition of AOA Focus