#48. Accommodation - types, paralysis and spasm of accomodation. Presbyopia.

Question 1

What is ACCOMMODATION?

Answer 1

• Dynamic Process of INCREASING the REFRACTIVE POWER of the eye.
• Ability of the eye to have a CLEAR IMAGE at DIFFERENT distances
• It DEPENDS SOLELY on the LENS to CHANGE its REFRACTIVE POWER

Question 2

What are the 4 TYPES of ACCOMMODATION?

Answer 2

1) TONIC Accommodation
- DUE to TONUS of CILIARY MUSCLE
- ACTIVE when STIMULUS ABSENT

2) PROXIMAL Accommodation
- INDUCED by AWARENESS of NEARNESS of a Target

• INDEPENDENT of actual DIOPTRIC Stimulus

3) REFLEX Accommodation
- AUTOMATIC Adjustment RESPONSE to BLUR
- MAINTAIN a CLEAR / SHARP Retinal Image

4) CONVERGENCE Accommodation
- AMOUNT of Accommodation STIMULATED / RELAXED

Question 3

What is the PARALYSIS of ACCOMMODATION?

Answer 3

• COMPLETE ABSENCE of Accommodation

Question 4

What are the CAUSES of PARALYSIS of ACCOMMODATION?

Answer 4

• ATROPINE
• INTERNAL OPHTHALMOPLEGIA = DUE to Neuritis with Diphtheria, Syphilis, Diabetes, Alcohol
• Complete 3rd Cranial Nerve Paralysis = DUE to Intracranial OR Orbital Causes
• SYSTEMIC Medications = Anti-hypertensives OR Antidepressants

Question 5

What are the CLINICAL FEATURES of PARALYSIS of ACCOMMODATION?

Answer 5

• Blurred Vision at NEAR
• Photophobia
• Diplopia
• Micropsia (Objects appear SMALLER than what they are)
• ENLARGED Pupils

Question 6

What is the TREATMENT for PARALYSIS of ACCOMMODATION?

Answer 6

** FIND the Cause!

• DARK Glasses = TO REDUCE Glare
• CONVEX Glasses = For NEAR Vision

Question 7

What is SPASM of ACCOMMODATION?

Answer 7

EXERTION of ABNORMALLY EXCESSIVE accommodation

Question 8

What are the CAUSES of SPASM of ACCOMMODATION?

Answer 8

• Drug-Induced = Using STRONG MIOTICS
• NEAR Work is performed with POOR Illumination
• BAD Reading Position
• State of NEUROSIS
• Mental Stress / Anxiety

Question 9

What are the CLINICAL FEATURES of SPASM of ACCOMMODATION?

Answer 9

• DEFECTIVE Vision = DUE to INDUCED Myopia
• Muscular IMBALANCE
• TRIGEMINAL Neuralgia
• DENTAL Lesion
• GENERAL Intoxication

Question 10

What is the TREATMENT for SPASM of ACCOMMODATION?

Answer 10

• RELAX the Ciliary Muscle = By ATROPINE for 4 weeks OR more
• PROHIBIT near work UNTIL PROMPT recovery
• ELIMINATE Causative Factors

Question 11

What is PRESBYOPIA?

Answer 11

• Condition of PHYSIOLOGICAL INSUFFICIENCY of Accommodation
• Leading to PROGRESSIVE FAIL in NEAR vision
• EMMETROPIC Eye’s Far Point is at AFFINITY but NEAR POINT is GENERALLY from 25cm

Question 12

What is the CAUSE of PRESBYOPIA?

Answer 12

• DECREASED Elasticity of LENS CAPSULE
• PROGRESIVE INCREASE in Size / Hardness of Lens Substance
• Age-Related DECLINE in CILIARY MUSCLE Power

Question 13

What are the SYMPTOMS of PRESBYOPIA?

Answer 13

• DIFFICULTIES in NEAR Vision
• COMPLAINTS of DIFFICULY reading SMALL Prints
• ASTHENOPIC Symptoms = DUE to FATIGUE of CILIARY MUSCLE after reading / doing near work

Question 14

What is the TREATMENT for PRESBYOPIA?

Answer 14

OPTICAL TREATMENT
- Prescribe appropriate CONVEX Glasses for near work

+ 1 DS = 40 - 45 y/o
+ 1.5 DS = 45 - 50 y/o
+ 2DS = 50 - 55 y/o
+ 2.5DS = 55 - 60 y/o

SURGICAL TREATMENT
- CORNEAL Procedures = Laser Based Procedure

• INTRAOCULAR Refractive Procedure
• SCLERA Procedures