#13. Peripheral vision. Visual field. Methods for examination. Changes in visual field – scotomata, anopsias concentric narrowing.

Question 1

What is PERIPHERAL VISION?

Answer 1

• The SIDE Vision
• Vision ELICITED VIA Stimuli FALLING on RETINAL AREAS
• DISTANT FROM the MACULA

Question 2

What is VISUAL FIELD?

Answer 2

• FULL EXTENT of the Area VISIBLE to eye
• That is FIXATING STRAIGHT AHEAD

Question 3

What is the NORMAL VISUAL FIELD?

Answer 3

• UPWARDS= 60°
• INWARDS= 60°
• DOWNWARDS= 70°
• OUTWARDS= MORE than&raquo_space; 90°

Question 4

What is the MAIN METHOD of Examination of the Visual Field?

Answer 4

PERIMETRY = Method to DESCRIBE Various Techniques that evaluate CENTRAL & PERIPHERAL Visual Fields, USING TARGETS of VARIOUS Sizes / Colours

Question 5

What are the 2 TYPES of EXAMINATION of the VISUAL FIELD?

Answer 5

1) KINETIC Perimetry

2) STATIC Perimetry

Question 6

What is KINETIC Perimetry?

Answer 6

• When TARGET is MOVED ACROSS the FUELD
• TO MAP OUT the 2D Extent of the Field
• It’s a Presentation of MOVING STIMULUS of KNOWN LUMINANCE
• FROM the Periphery, TOWARDS –> CENTRE, until it’s perceived

Question 7

What is STATIC Perimetry?

Answer 7

0 It’s a Presentation of NON-MOVING STIMULUS of VARYING LUMINANCE

• That is REMAINED IN SAME POSITION
• TO obtain a VERTICAL BOUNDARY of the Visual Field

Question 8

What are the USES of PERIMETRY?

Answer 8

• Glaucoma
• Retina Diseases
• Follow-up of LASER EYE Treatment of DIABETIC RETINOPATHY
• Neurological Disorders = Brain Tumours, Multiple Sclerosis, Head Trauma, Cerebral Aneurysms

Question 9

What is SCOTOMA?

Answer 9

• ABSOLUTE or RELATIVE Area
• OF DEPRESSED Visual Function, SURROUNDED by NORMAL Vision

E.g. Glaucoma / Optic Neuritis

Question 10

What are the 4 TYPES of SCOTOMA?

Answer 10

1) ABSOLUTE Scotoma
- ALL Vision is LOST
- NO LIGHT Perception

2) RELATIVE Scotoma = VARIABLE amount of Vision REMAINS

3) POSITIVE Scotoma = Px APPRECIATES DARK AREA in their Field of Vision

4) NEGATIVE Scotoma = DEFECT DETECTED when Visual Field is BEING RECORDED

Question 11

What TYPE of SCOTOMA Occurs in a MIGRAINE?

Answer 11

Scintillating Scotoma

Question 12

What is the CAUSE of SCINTILLATING Scotoma?

Answer 12

• DUE to TRANSIENT VASOASPASM
• OF the POSTERIOR CEREBRAL Artery (Supplies the VISUAL CORTEX)

Question 13

What is ANOPSIA?

Answer 13

AKA Blindness!

• ABSENCE of VISION
• DUE to STRUCTURAL DEFECT of Eyes
• DUE to LACK of the EYES COMPLETELY

Question 14

What are the CAUSES of ANOPSIA?

Answer 14

• MECHANICAL Trauma
• INFLAMMATION in
  a. Multiple Sclerosis
  b. Lupus Erythematosus
• DIABETIC Retinopathy
• AGE-RELATED MACULAR Degeneration
• CATARACTs

Question 15

What is the TREATMENT for ANOPSIA?

Answer 15

REFRACTIVE Surgery = TO RESTORE Corneal Function

OPTICAL Aid / Correction
- Contact Lenses
- Glasses

Question 15

What is the TREATMENT for ANOPSIA?

Answer 15

REFRACTIVE Surgery = TO RESTORE Corneal Function

OPTICAL Aid / Correction
- Contact Lenses
- Glasses