1. What are visual disorders? Visual disorders are abnormalities of the eye, the optic nerve, the optic tracts,
or the brain that may cause a loss of visual acuity or visual fields. A loss of visual
acuity limits your ability to distinguish detail, read, or do fine work. A loss of
visual fields limits your ability to perceive visual stimuli in the peripheral extent
2. How do we define statutory blindness? Statutory blindness is blindness as defined in sections 216(i)(1) and 1614(a)(2)
of the Social Security Act (the Act). The Act defines blindness as visual acuity
of 20/200 or less in the better eye with the use of a correcting lens. We use your
best-corrected visual acuity for distance in the better eye when we determine if this
definition is met. The Act also provides that an eye that has a visual field limitation
such that the widest diameter of the visual field subtends an angle no greater than
20 degrees is considered as having visual acuity of 20/200 or less. You have statutory
blindness only if your visual disorder meets the criteria of 2.02 or 2.03A. You do
not have statutory blindness if your visual disorder medically equals the criteria
of 2.02 or 2.03A, or if it meets or medically equals 2.03B, 2.03C, or 2.04. If your
visual disorder medically equals the criteria of 2.02 or 2.03A, or if it meets or
medically equals 2.03B, 2.03C, or 2.04, we will find that you have a disability if
your visual disorder also meets the duration requirement.
3. What evidence do we need to establish statutory blindness under title XVI? For title XVI, the only evidence we need to establish statutory blindness is evidence
showing that your visual acuity in your better eye or your visual field in your better
eye meets the criteria in 2.00A2, provided that those measurements are consistent
with the other evidence in your case record. We do not need to document the cause
of your blindness. Also, there is no duration requirement for statutory blindness
under title XVI (see §§416.981 and 416.983).
4. What evidence do we need to evaluate visual disorders, including those that result
in statutory blindness under title II?
a. To evaluate your visual disorder, we usually need a report of an eye examination
that includes measurements of the best-corrected visual acuity or the extent of the
visual fields, as appropriate. If there is a loss of visual acuity or visual fields,
the cause of the loss must be documented. A standard eye examination will usually
reveal the cause of any visual acuity loss. An eye examination can also reveal the
cause of some types of visual field deficits. If the eye examination does not reveal
the cause of the visual loss, we will request the information that was used to establish
the presence of the visual disorder.
b. A cortical visual disorder is a disturbance of the posterior visual pathways or
occipital lobes of the brain in which the visual system does not interpret what the
eyes are seeing. It may result from such causes as traumatic brain injury, stroke,
cardiac arrest, near drowning, a central nervous system infection such as meningitis
or encephalitis, a tumor, or surgery. It can be temporary or permanent, and the amount
of visual loss can vary. It is possible to have a cortical visual disorder and not
have any abnormalities observed in a standard eye examination. Therefore, a diagnosis
of a cortical visual disorder must be confirmed by documentation of the cause of the
brain lesion. If neuroimaging or visual evoked response (VER) testing was performed,
we will request a copy of the report or other medical evidence that describes the
findings in the report.
c. If your visual disorder does not satisfy the criteria in 2.02, 2.03, or 2.04, we
will also request a description of how your visual disorder impacts your ability to
5. How do we measure best-corrected visual acuity?
a. Testing for visual acuity. When we need to measure your best-corrected visual acuity, we will use visual acuity
testing that was carried out using Snellen methodology or any other testing methodology
that is comparable to Snellen methodology.
b. Determining best-corrected visual acuity.
(i) Best-corrected visual acuity is the optimal visual acuity attainable with the
use of a corrective lens. In some instances, this assessment may be performed using
a specialized lens; for example, a contact lens. We will use the visual acuity measurements
obtained with a specialized lens only if you have demonstrated the ability to use
the specialized lens on a sustained basis. However, we will not use visual acuity
measurements obtained with telescopic lenses because they significantly reduce the
visual field. If you have an absent response to VER testing in an eye, we can determine
that your best-corrected visual acuity is 20/200 or less in that eye. However, if
you have a positive response to VER testing in an eye, we will not use that result
to determine your best-corrected visual acuity in that eye. Additionally, we will
not use the results of pinhole testing or automated refraction acuity to determine
your best-corrected visual acuity.
(ii) We will use the best-corrected visual acuity for distance in your better eye
when we determine whether your loss of visual acuity satisfies the criteria in 2.02.
The best-corrected visual acuity for distance is usually measured by determining
what you can see from 20 feet. If your visual acuity is measured for a distance other
than 20 feet, we will convert it to a 20-foot measurement. For example, if your visual
acuity is measured at 10 feet and is reported as 10/40, we will convert this to 20/80.
6. How do we measure visual fields?
a. Testing for visual fields.
(i) We generally need visual field testing when you have a visual disorder that could
result in visual field loss, such as glaucoma, retinitis pigmentosa, or optic neuropathy,
or when you display behaviors that suggest a visual field loss.
(ii) When we need to measure the extent of your visual field loss, we will use visual
field measurements obtained with an automated static threshold perimetry test performed
on a perimeter, like the Humphrey Field Analyzer, that satisfies all of the following
A. The perimeter must use optical projection to generate the test stimuli.
B. The perimeter must have an internal normative database for automatically comparing
your performance with that of the general population.
C. The perimeter must have a statistical analysis package that is able to calculate
visual field indices, particularly mean deviation.
D. The perimeter must demonstrate the ability to correctly detect visual field loss
and correctly identify normal visual fields.
E. The perimeter must demonstrate good test-retest reliability.
F. The perimeter must have undergone clinical validation studies by three or more independent
laboratories with results published in peer-reviewed ophthalmic journals.
(iii) The test must use a white size III Goldmann stimulus and a 31.5 apostilb (10
cd/m2) white background. The stimuli locations must be no more than 6 degrees apart
horizontally or vertically. Measurements must be reported on standard charts and
include a description of the size and intensity of the test stimulus.
(iv) To determine statutory blindness based on visual field loss (2.03A), we need
a test that measures the central 24 to 30 degrees of the visual field; that is, the
area measuring 24 to 30 degrees from the point of fixation. Acceptable tests include
the Humphrey 30-2 or 24-2 tests.
(v) The criterion in 2.03B is based on the use of a test performed on a Humphrey Field
Analyzer that measures the central 30 degrees of the visual field. We can also use
comparable results from other acceptable perimeters, for example, a mean defect of
22 on an acceptable Octopus test, to determine that the criterion in 2.03B is met.
We cannot use tests that do not measure the central 30 degrees of the visual field,
such as the Humphrey 24-2 test, to determine if your impairment meets or medically
(vi) We measure the extent of visual field loss by determining the portion of the
visual field in which you can see a white III4e stimulus. The “III” refers to the
standard Goldmann test stimulus size III, and the “4e” refers to the standard Goldmann
intensity filters used to determine the intensity of the stimulus.
(vii) In automated static threshold perimetry, the intensity of the stimulus varies.
The intensity of the stimulus is expressed in decibels (dB). We need to determine
the dB level that corresponds to a 4e intensity for the particular perimeter being
used. We will then use the dB printout to determine which points would be seen at
a 4e intensity level. For example, in Humphrey Field Analyzers, a 10 dB stimulus
is equivalent to a 4e stimulus. A dB level that is higher than 10 represents a dimmer
stimulus, while a dB level that is lower than 10 represents a brighter stimulus. Therefore,
for tests performed on Humphrey Field Analyzers, any point seen at 10 dB or higher
is a point that would be seen with a 4e stimulus.
(viii) We can also use visual field measurements obtained using kinetic perimetry,
such as the Humphrey “SSA Test Kinetic” or Goldmann perimetry, instead of automated
static threshold perimetry. The kinetic test must use a white III4e stimulus projected
on a white 31.5 apostilb (10 cd/m2) background. In automated kinetic tests, such
as the Humphrey “SSA Test Kinetic,” testing along a meridian stops when you see the
stimulus. Because of this, automated kinetic testing does not detect limitations
in the central visual field. If your visual disorder has progressed to the point
at which it is likely to result in a significant limitation in the central visual
field, such as a scotoma (see 2.00A8c), we will not use automated kinetic perimetry
to evaluate your visual field loss. Instead, we will assess your visual field loss
using automated static threshold perimetry or manual kinetic perimetry.
(ix) We will not use the results of visual field screening tests, such as confrontation
tests, tangent screen tests, or automated static screening tests, to determine that
your impairment meets or medically equals a listing or to evaluate your residual functional
capacity. However, we can consider normal results from visual field screening tests
to determine whether your visual disorder is severe when these test results are consistent
with the other evidence in your case record. (See §§404.1520(c), 404.1521, 416.920(c),
and 416.921.) We will not consider normal test results to be consistent with the
other evidence if either of the following applies:
A. The clinical findings indicate that your visual disorder has progressed to the point
that it is likely to cause visual field loss, or
B. You have a history of an operative procedure for retinal detachment.
b. Use of corrective lenses. You must not wear eyeglasses during the visual field examination because they limit
your field of vision. Contact lenses or perimetric lenses may be used to correct
visual acuity during the visual field examination in order to obtain the most accurate
visual field measurements. For this single purpose, you do not need to demonstrate
that you have the ability to use the contact or perimetric lenses on a sustained basis.
7. How do we calculate visual efficiency?
a. Visual acuity efficiency. We use the percentage shown in Table 1 that corresponds to the best-corrected visual
acuity for distance in your better eye.
b. Visual field efficiency. We use kinetic perimetry to calculate visual field efficiency by adding the number
of degrees seen along the eight principal meridians in your better eye and dividing
by 500. (See Table 2.)
c. Visual efficiency. We calculate the percent of visual efficiency by multiplying the visual acuity efficiency
by the visual field efficiency and converting the decimal to a percentage. For example,
if your visual acuity efficiency is 75 percent and your visual field efficiency is
64 percent, we will multiply 0.75 x 0.64 to determine that your visual efficiency
is 0.48, or 48 percent.
8. How do we evaluate specific visual problems?
a. Statutory blindness. Most test charts that use Snellen methodology do not have lines that measure visual
acuity between 20/100 and 20/200. Newer test charts, such as the Bailey-Lovie or
the Early Treatment Diabetic Retinopathy Study (ETDRS), do have lines that measure
visual acuity between 20/100 and 20/200. If your visual acuity is measured with one
of these newer charts, and you cannot read any of the letters on the 20/100 line,
we will determine that you have statutory blindness based on a visual acuity of 20/200
or less. For example, if your best-corrected visual acuity for distance in the better
eye was determined to be 20/160 using an ETDRS chart, we will find that you have statutory
blindness. Regardless of the type of test chart used, you do not have statutory blindness
if you can read at least one letter on the 20/100 line. For example, if your best-corrected
visual acuity for distance in the better eye was determined to be 20/125+1 using an
ETDRS chart, we will find that you do not have statutory blindness as you are able
to read one letter on the 20/100 line.
b. Blepharospasm. This movement disorder is characterized by repetitive, bilateral, involuntary closure
of the eyelids. If you have this disorder, you may have measurable visual acuities
and visual fields that do not satisfy the criteria of 2.02 or 2.03. Blepharospasm
generally responds to therapy. However, if therapy is not effective, we will consider
how the involuntary closure of your eyelids affects your ability to maintain visual
functioning over time.
c. Scotoma. A scotoma is a non-seeing area in the visual field surrounded by a seeing area. When
we measure the visual field, we subtract the length of any scotoma, other than the
normal blind spot, from the overall length of any diameter on which it falls.