2. Accommodation
The ability of crystaline lens to
increase it's convexcity with the
help of constriction of ciliary
muscle and relexation of the
zonules to see the clear image.
3.
4.
5. Near point or punctum proximum
The nearest point at which small object can be
seen clear.
6. Far point or punctum remotum
The farthest point at which small
objects can be seen clear.
Hypermetropic :- far point behind the
eye.
Myopoic :- far point front of the eye.
Emmetropic :- far point at infinity
7. • The distance between
far point and near point.
• a= r - p
Range of
Accommodation
Amplitude of
Accommodation
• The difference between
dioptric power , needed
to focus at near point to
far point.
• A = P - R.
12. Causes of presbyopia
1 ) Age related changes : - Decrease elasticity of lens capsule.
progressive increase in size and hardness in
the lens.
2) pre mature presbyopia:- uncorrected hypermetropia
presenile weakness of ciliary muscle
chronic simple glaucoma
wekning of ciliary muscle power
premature sclerosis.
14. Treatment
• Prescribe near vision addition according to
age or patient's need.
• Single vision reading glasses, bifocal , trifocal
and multifocal.
• Always find out distance refractive error first
and correct it.
16. Causes
• Premature sclerosis of lens.
• Weakness of ciliary muscles ,
• Due to systemic causes :- Malnutrition ,
• Pregnancy , DM , MS
• Due to local cause : - Primary open angle
glaucoma,
• Mild cyclitis
17. Symptoms
• Headache , Fatigue , Near vision
blur
• Over and under convergence
• Intemittent diplopia
18.
19. Treatment
• Treat the causes
• Spectecle correction :-
• For near weakest convex lens prescribe
• For Convergence insufficiency base out prism
prescribe
• For excessive convergence full sph correction
prescribe
• Accommodative exercise :- vision therapy (flippers)
• Take proper food nutrition
20. ILL-SUSTAINED
ACCOMMODATION
It is the condition in which the range of
accommodation is normal but it cannot be
sustained for proper time period.
Eye fatigue produced when do long time near
work .
NPA is recede during close work.
21. Etiology :- Accommodative fatigue
Debiliting illness
Symptom :-
Feeling tired very
soon while doing
near work.
22. Accommodation Inertia
Difficulty in changing focus from
distance to near vision .
It takes some more time to clear the
distance object after looking the near
object.
23. Etiology Treatment
• Prolong close
work and occular
motor imbalance
• Correct
refractive error
• Do
accommodative
25. Causes
• Drug induced myopia : -
atropine,homatropine
• Internal ophthalmoplegia
• 3rd nerve paralysis
• paralysis of accommodation
• head injury
26. Symptoms
• blurring of near vision.
• photophobia
• micropsia
• 3rd nerve palsy
• abnormal receding of near point
27. Treatment
• self recovery of drug induced cycloplegia.
• Dark glasses for photophobia
• convex lens for near vision correction.
28. Excessive Accommodation
• when accommodation efforts more than normal for
near work.
• CAUSES : - young hypermetropes
• young myopes
• astigmatic error
• presbyopes in the begining
• inproper ill fitting spectacles
• FACTOR : - A large number of near work
29. Symptoms
• varying degree of blurred vision
• headaches, fatigue,discomfort in eyes
• near vision difficulty
• macropsia
• miosis
• far point and near point both are brought nearer to
the eyes.
30. Treatment
• optical : - cyclopegic refraction (RE should be corrected)
• General : -
31. Spasm of Accommodation
Abnormal excessive accommodation which is out of the voluntary
control of the individual.
CAUSES : - drug induced spasm of accommodation
spontaneous SOA - uncorrected hypermetropia
astigmatism and myopia
bad illumination , bed reading
iridocyclitis , spasm of near reflex , lesions of brsinstem
toxic reaction of exogenous poisons
32. Symptoms
• blurred vision due to induced
pseudomyopia
• asthenopic symptoms > visual
symptoms
• headache,browache
• near point is close
33. Treatment
• Relaxation of ciliary muscle :- cycloplegia for
long time
• optical : -
• correcting spectacles should be worn
immidiately when eyes are used again