Visual impairment and blindness can be diagnosed using tests of visual acuity and visual field. Visual acuity tests like the Snellen chart measure how far away a patient can read letters of decreasing size, while visual field tests check for peripheral vision loss. Diagnosis determines the level of vision impairment from mild to severe and blindness. Treatment depends on the underlying cause, and may include refraction and glasses, medication, cataract surgery, or therapies to support coping.

1. Diagnosis And
Treatment of
Blindness
SRUTHI LAKSHMANAN
RA1841002010134

2. Visual Impairment and Blindness
*Visual field:-
Range of vision (peripheral vision of eyes)
* Visual acuity:-
Resolving power of eye or ability to see
2 separate objects.
BLINDNESS:-
Extremely poor acuity(<3/60), full field of vision
Poor acuity(between 3/60 & 6/60), severe reduction in visual
field
Average acuity(6/60 or better), extremely reduced visual field

3. Diagnosis
TEST FORVISUAL ACUITY
SNELLEN’S CHART
• Contains: progressive shortening of random letters and
numbers.
• Distance: placed 6 meters away from the patient
• Procedure: patient is asked to read the letters with each
eye separately and both together
• Observation: ability to read letters determines acuity
• Interpretation: Score obtained has 2 numbers
eg): 6 how far away a pt. was successfully able to read letters
60 how far away a person with healthy vision reads

4. Interpretation
• Distance- vision impairment:-
Partial sight impairment:-
 Mild- acuity worse than 6/12
Moderate- acuity worse than 6/18
Severe- acuity worse than 6/60
Severe sight impairment:-
BLINDNESS-acuity worse than 3/60
• Near- vision impairment:-
Acuity worse than N6 or M0.8 at 40cm with existing correction.

5. Other tests
Visual field test:
• Procedure: A device is
strapped over the patient’s
eyes. Lights are flashed on
and off in the patient’s
peripheral vision and the
pt. is asked to press the
light button every time
they see light.

6. TREATMENT
Depends on cause of blindness:-
 due to nutritional deficiency: Dietary changes (Vitamin
A for night blindness)
Due to refractive error: doing refraction and providing
appropriate spectacles
Inflammatory and infectious causes: medication in form
of drops or pills
Due to cataract: cataract surgery restores sight and
intraocular lens implantation after removal of opaque
natural lens
Therapies: Support groups and Sensory processing