PHYSIOLOGY OF VISION Flashcards
Light is a form of electromagnetic
radiation composed of particle called…….
Photons
that travel in wavelike fashion.
Protection is provided by :
1……….
2……….
1-Eyelashes
2- Secretion of tears from the Lacrimal glands
Functions of sclera :
1……
2……
A. Provide the attachment for the ocular muscles
B. Provide mechanical support
The functions of cornea :
A- Allows the light to pass to the inside of the eye (that is why it is transparent).
B- It refracts \ bends \ twist \ change the angle of the light rays.
Uvea is …..
Choroid
Ciliary Muscles : provide the attachment to the lens through ………
suspensory ligaments or
zonules
This choroid layer get modified anteriorly and give rise to……..
ciliary body
The pathway of light into the eye:
1- The light passes into the cornea
2- Anterior chamber: a space between the cornea and the iris
3- Pupil
4 Posterior chamber: a thin space between the iris and the lens
5- lens
6- Vitreous chamber or cavity
7- focal point in the retina
…………………… is a transparent fluid which provide nutrition to the
avascular cornea”
Aquas humor
Ability of the eye to change the focal length of the
lens by changing the curvature of the eye lens
Accomodation
In the Accommodation the Ability of the eye to change the focal length of the
lens by changing the curvature or concavity of the eye lens
curvature
Accommodation is the Ability of the eye to change the ………..
focal length of the lens
Which structures response to change the shape
of the lens during accommodation ?
the ciliary muscle and suspensory ligaments
The lens assumes a more spherical shape
This occurs during accommodation on a…………object being viewed
Closer
Focusing on near objects
needs less/more bending of the
light rays
More
Lens flatter during accommodation on a……. distant object being viewed
more
The Accommodation occurs in both …….. and …..
Lens and Irus
Parasympathetic causes pupillary ……….. by contracting the ..…….muscle of the eye
constriction
circular
Sympathetic causes pupillary ……… by contracting the ……muscle of the eye.
dilatation
radial
Refraction (conversion) means :
changing the angle of the light.
The……. and…….. are refractive structures of the eye They offer…….. surfaces to focus diverging light rays
cornea
lens
convex
What is the constant refractive structures ?
cornea
What is the modifiable refractive structures ?
the shape of the lens
Convex structures of the eye produce…….. of these diverging rays
convergence
The refractive power of a lens is measured in……..
diopters
The human eye has
………..refractive power of diopters at rest
60
The nearest point to the eye at which an object can be brought into clear focus by accommodation is called the
…………..
near point of vision
The near response is compost of 3 parts
accommodation, the visual axes converge and the pupils
The near point recedes throughout life with
advancing age results in loss of accommodation
Condition is known as…….
Presbyopia
Emmetropia
Normal eye
