Physiology Of Optics Flashcards

1
Q

Describe cornea

A

Transparent
Non vascularized
Provide protective coating

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2
Q

Effect of the obstruction of aqueous humor

A

Increase intraocular pressure

Glaucoma - leads to damage of retina and optic nerve, cause blindness

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3
Q

3 functions of aqueous humor

A

Maintain eye pressure

Maintain cornea shape

Nourish lens and cornea

Immunological function

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4
Q

Function of lens

A

Focuses light ON the RETINA

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5
Q

Pupil and muscle of iris in bright light

A

Circular muscle of iris contract

Pupil constrict

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6
Q

Pupil and muscle of iris in dim light

A

Circular muscle of iris relax

Radial muscle of iris contract

Pupil dilates

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7
Q

Dilation of pupil

A

Sympathetic stimulation : mydriasis

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8
Q

Pupil constriction

A

Parasympathetic stimulation : miosis

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9
Q

Functions of vitreous humor

A

Mainatain posterior pressure to lens

Clear debris by phagocyte

Help clean the retina

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10
Q

Describe emmetropia

A

Normal eye : light rays from object are parallel and focus on the retina without effort

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11
Q

Describe the lens in distance vision (3m)

A

Ciliary muscle relax

Zonular ligament contract / stretch

Lens is thin

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12
Q

Describe lens in near vision (3m)

A

Ciliary muscles contract

Zonular ligaments relax

Lens is thicker

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13
Q

Describe visual axis

A

Midpoint of visual field to fovea

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14
Q

Describe optic axis

A

Longest A-P diameter of the eye, middle of cornea to posterior pole

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15
Q

Describe presbyopia and how it is corrected

A

Loss of accomodation of lens because decrease in elasticity as aging

Corrected by convex lens

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16
Q

Describe agtimatism and how it can be corrected

A

Non uniform curbpvature of the cornea

Corrected by cylindrical lens

17
Q

Describe error of refraction : HYPEROPIA and how it can be corrected

A

Light rays focused on the POSTERIOR to the retina
Eye ball too short
Farsightedness

Corrected by convex lens

18
Q

Describe error of refraction : MYOPIA and how it is corrected

A

Light rays focused ANTERIOR to retina
Eye ball too long
Nearsightedness

Corrected by concave lens

19
Q

Describe visual acuity

A

Sharpness of the eye ; degree to which details and contours of objects are perceived

20
Q

Visual acquity influenced by

A

Optical factors

Retinal factors

Stimulus factors

21
Q

How visual acquity is determined

A

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