Vision and the world of Colours Flashcards
Define Near point
The nearest point at which objects can be seen distinctly
Near point of an eye with healthy vision
25 cm
Define far point
The farthest point at which objecgt can be seen distinctly
Far point of an healthy eye is at infinity
Power of accommodation of eye
The ablity of the eye to form an image on the retina by adjusting the focal length of the lens in the eye, by varying the curvature of the lense, irrespective of the position of the object
Which lense is used for long-sightedness
also known as hypermetropia
convex lense
Which lense is used for shory-sightedness
AKA Myopia
Concave lense
For eye donation ; the cornea of the doner shoule be harvested in how many hours
6
What is prsistance of vision
When an person views an object, it’s image remains in the retina for 0.0625s(1/16s).
Which colour has the highest wavelength
Higher waverlength means less scattering
Red
As a result they travel greater distance
Tyndal effect
When rays of light pass through a colloidal fluid or suspension, the tiny particles get illuminted due to scattering. Due to this the path of light is made visible.
Intensity of scatering depends on the size of the particles
Composite light
Any colour that is composed of more than one colour
The phenomenon of splitting up of a composite light is known as
Dispersion of light
What is Presbyopia
Defect in the eye
For elderly people the distance of to the nearpoint is greater than 25cm. This is due to the diminishing ablity of the ciliary muscles. For such people the power of accommodation will be less
mostly seen in elderly people
