PRELIMS Flashcards
‘Educationally, legally, functionally’
- Often used to indicate visual impairment requiring specialist services or financial
assistance
- Carries the perception that ‘all sight is gone
BLIND
A person one who has impairment of visual function for whom full
remediation is not possible by conventional spectacles, contact lenses or medical
intervention and which causes restriction in that person’s everyday life
Low Vision
Broader spectrum of sight loss
- ‘Partial sight, low vision, subnormal vision’
Visual Impairmen
In 1950s and 1960, it was defined as visual acuity of 20/70 or worse with the best
conventional optical correction
Subnormal Vision
In 1975, defined as reduced central acuity or visual field loss which, even with the best
optical correction provided by regular lenses, still results in visual impairment
Low Vision
one of the major problems to collect data was non-standardization of definition. Around
65 different types of definitions were used worldwide to describe the definition of blindness and
poor vision
1973
low vision was defined as reduced visual acuity by disorder of the eye or visual system. A
level of vision which cannot be improved to within normal limits by medication, surgery, or use
of conventional correction.
1976
WHO proposed a standard classification that would be used worldwide. This was included
in 10th revision of the International Classification of Diseases (ICD-10) but unfortunately this
classification is not accepted worldwide although references to it are now common.
1978
WHO offered a new definition of Low Vision
1992
Refers to conditions encompassing the continuum from partial sight to blindness.
VIDION IMPAIRMENT
defined as visual acuity less than 3/60 in the better eye after best possible correction and
visual field < 10 degree from the point of fixation.
Blindness
is defined as visual acuity 3/60 (20/400) to less than 6/18 (20/70) in the better eye after
best possible correction in the better eye and visual field <20 degree from the point of
fixation.
WHO definition of Low Vision
refers to an individual’s functional visual ability in spite of loss, how an individual develops
creative ways of adapting to various situations. The use of low vision aids increases visual
efficiency. It depends on training, experience, intelligence level, and personality
characteristics of the individual, as well as other disabilities that may interfere with normal
function.
Visual Efficiency
the international standard diagnostic classification for all general epidemiological, many
health managements purposes and clinical use.
- It is used to classify diseases and other health problems recorded on many types of health
and vital records including death certificates and health records.
International Classification of Disease
It gives rise to anatomical changes in the visual organs
- For example, Glaucoma in its early stages can go unnoticed by the patient, without
affecting abilities
Visual Disorder
Functional loss from a visual disorder.
- It affects visual acuity, visual field, color vision, contrast sensitivity
Visual Impairment
It gives rise to vision-related changes in the skill and abilities
- It is measured in terms of the skills - can or cannot perform.
Visual Disability
It has psychosocial and economic consequences of visual loss.
- Skills of the person gets hampered
- Giving rise to barriers in the environment both physical and social.
Visual Handicap
Who are the Low Vision patients?
Patients with congenital eye diseases and diseases occurring early in life
2. Patients with degenerative diseases occurring later in life
Persons with such condition may indicate a diminution of vision, haziness, or foggy
vision.
Lower central acuity or fluctuating vision
Persons describes distortion of vision. Objects appear to bulge,
curve or look funny.
Metamorphopsia
Person either complains of abnormal sensitivity to light or avoid high levels of
illumination recovery, from glare, is slow and adaptation of light is difficult.
Photophobia
Person indicates they cannot detect colors or functional observations show that they
have trouble identifying colors
Color Vision Defects
Persons report they have vision in specified sectors of the visual field and parts of the
object to be viewed are always missing.
Visual Field Defects
Persons indicate decreased vision at night and difficulty in performing specific task at
night. This condition can be confirmed by clinical test or electrodiagnostic testing.
Night Blindness
Persons with this condition sees floaters or spots before their eyes, which momentarily
interferes with vision. Such symptoms may indicate an acute pathology.
Entopic Images
Persons with this condition reports that the world seems to be moving or jumping
around. This condition may be sign of neurological disorders. Therefore patient should
be referred to a neurologist
Oscillopsia
Partially or complete absence of iris
Aniridia
Present at birth or become apparent in the first year of life. It causes
significant visual morbidity because of associated amblyopia, even with
early surgical treatment; most common cause of leukocoria.
Congenital Catarac
Rare life-threatening tumor with complex genetic inheritance; most
common cause of leukocoria.
Retinoblastoma
Often presents with a “watery eye”. Crucial history taking should be
determine whether that ‘epiphora’ was present at birth or developed later.
CONGENITAL GLAUCOMA
Rare causes of poor central vision. High refractive errors should always be
kept in mind in these cases
Nystagmus
If the baby was of low birthweight of less than 1500 g or pre-term (born
earlier than 37 weeks), ROP should be considered.
Retinopathy of Prematurity
The pupillary reflexes are normal, as are the optic discs, but the baby may
be photophobic. The fundus will appear albinotic or blond.
Ocular Albinism
Manifests with normal ophthalmic findings, including the presence of
normal pupillary reflexes. Electroencephalogram (EEG) is abnormal; baby
often has signs of developmental delay and may have midline defects
including cleft lip or palate.
Cerebral blindness
- Involves no ophthalmological or electrophysiological abnormality. The baby
is often premature or small for dates. Although prognosis for vision is
generally good, a small proportion of patients are left with a residual deficit.
Delayed visual development
Often shows no abnormality on fundoscopy in the early stages, however
the optic discs can sometimes appear slightly pale and early thinning of the
arterioles is an important early sign in this condition.
Leber’s congenital amaurosis
Can be subtle and easily missed unless specifically looked for with the direct
ophthalmoscope. Other signs may include the presence of nystagmus,
slugging pupillary reflexes and the characteristic optic disc double ring sign.
Optic disc hypoplasia
Result of complex hereditary and environmental factors
High Myopia
Genetic condition that affects connective tissue of the fibrillin gene that
affects the cardiovascular, musculoskeletal, and ophthalmic systems.
Fibrillin is found in the ciliary zonule and lens capsule. Defect in fibrillin
causes ectopia lentis, axial myopia, glaucoma and retinal complications
- Most common cause of nontraumatic ectopia lentis
Marfan’s Syndrome
Early-onset may report night blindness or restriction of visual fields, which
is often manifested as clumsiness
Retinitis Pigmentosa
Progressive anteroposterior elongation of the scleral envelope associated
with a range of secondary ocular changes, which relates to mechanical
stretching of related tissues.
Pathological Myopia
Inflammation of the optic nerve; most common cause of unilateral painful
visual loss in a young adult.
Optic Neuritis
Lesions or inflammation encompasses the clinical entities of retinitis,
choiroditis, and retinal vasculitis
Posterior Uveitis
Serous retinal detachments commonly seen in the macular region. RPE
detachment which facilitates the leakage of plasma into the subretinal
space.
. Central Serous Retinopathy
Conditions Affecting the Elderly
- Age-related Macular Degeneration
- Diabetic Retinopathy
- Hypertensive Retinopathy
- Cataract
- Glaucoma
- Central Retinal Vein Occlusion
- Central Retinal Artery Occlusion
- Cerebrovascular accidents and visual function
Affects the ability to see the objects or people in direct line of vision
- Color vision may be affected
Central Visual Field Loss
Difficulty with individual travel
- Banging with obstacles on the sides such as furniture
- Need for increased in illumination
- Decreased visual efficiency: visual skills (scanning and tracking), saccades (horizontal and
vertical)
- Light and dark adaptation
Peripheral Visual Field Loss
Affects ability to perceive sharpness of details due to alteration in the refractive media of
the eye
- Patient may suffer double vision
- Problems with poor night vision, poor contrast, and glare
- Difficulty judging distance
Over-all Blur
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