Is anormal condition associated with age in which
accommadation tall short of the demand for the
usual reading range .
Causes of decline of accommadition:
1) inelastic lens (rigid)
2) Weakness of the ciliary muscle.
Absence of the crystalline lens from pupillary
3) An intra –ocular surgury.
An eye with an intra ocular lens
3. Accommodation :-
Is ability of the eye to increase its refractivity by a
change in crystalline lens .
The acco is concentration with veiwing of object
closer than optical infinity (reading manily).
Contracture of ciliary muscle & relaxation of the
Suspensory ligment the lens become more convex
increase in thickness and decrease in diameter.
4. Amplitude of accommodation :
Is total plus power which could added to eye
optical system (up 14D-0.5D) variation of
accommodation through our life (with advancing
Far point :(relax acco)(punctum)(remotum)
Near point:(fully excreted)(proximum).
1. Axial hypermetropia(short axial length)
4. Dislocation of the crystalline lens posteriorly.
The hypermetropia eye is aweak eye (lacks
plus power corected with plus lenses ).
1. Small eye
2. Small (constricted)pupil
3. Shallow anterior champer.
there synrkientic action:
Difficality of during near task
Tendency to develop diplopia
Tendency to develop squint