Anatomy
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more anatomy
Astigmatism
Refractive Conditions
100
Latin term for both eyes
What is Oculus Uterque or O.U.?
100
a resilient, transparent structure in the eye that focuses light by changing its front surface curvature. the diameter of the lens is 9-10 mm and thickness is 4-5 mm
What is crystalline lens?
100
the eye muscle that moves the eye downward and inward
What is inferior rectus?
100
present when images fall on the retina at two different points, 90 degress apart. This condition can be corrected with glasses or contact lenses.
What is a regular astigmatism?
100
the eyes inability to focus for near due to a lack of accommodation. Natural occurrence of aging. Two causes for the onset: layers of cells of the crystalline lens become rigid and the lens cant reshape easily or the suspensory ligaments weaken no longer able to help the lens reshape.
What is presbyopia? This is first noticed between the ages of 40-50 and can be correctedwith reading glasses and or multifocals.
200
bony cavity or socket that houses the eye. Function to protect the eye and provide structure for the attachment of the ocular muscles.
What is the orbit?
200
controls the focusing power (accommadation) of the eye by changing the shape of the crystalline lens.
What is ciliary muscle?
200
the drainage system that the aqueous humor is replaced or drained.
What is canal of Schlemm?
200
present when images fall on two different points on the retina, however the images are NOT 90 degrees apart.
What is irregular astigmatism?
200
present when two different images are formed on the retina. this may be treated with corrected with glasses.
What is double vision or diplopia?
300
folds of skin that serve as protective coverings for the globe and the cornea. Also regulate incoming light.
What are eyelids?
300
a watery substance that fills the anterior chamber and posterior chambers. Function is to maintain the shape of these chambers and regulating the intraocularpressure. it also supplies the crystalline lens and cornea with nutrients. This substance is constantly being replaced and drains through the canal of schlemm.
What is aqueous humor?
300
as the ciliary muscles contract, they release tension on the ___________ which allow the crystalline lens to become more sharply curved. Providing accommodation.
What is suspensory ligaments?
300
when the cornea is more curved in the veritcal meridian than the horizontal meridian the patient is said to have the most common astigmatism. Doctor would prescribe a cylinder lens having the axis placed at or near 180 degrees.
What is "with the rule" astigmatism?
300
caused by a muscle imbalance that prohibits binocular vision. this may be corrected with glasses
What is crossed eye or strabismus?
400
a thin transparent mucous membrane that lines the posterior surface of the lids
What is the conjunctiva?
400
a shutter-like muscle that forms the colored part of the eye and also controls the amount of the light entering the eye. this is the opening in the iris and it dilates in dim light and constricts in bright light. Involuntary reactions. avg size is 3-5 mm.
What is iris and pupil?
400
where the blind spot is located
What is optic disk?
400
when the cornea is more curved in the horizontal meridian than in the vertical meridian, the patient is said to have this and the doctor would prescibe a cylinder lens having the axis placed at oe near 90 degrees.
What is "against the rule" astigmatism?
400
an involuntary, rapid movement or rotation of the eye. often associated with photophobia.
What is nystagmus?
500
the margin at which the cornea and sclera meet
What is the conjunctiva?
500
this is located in the retina. and within this is the _____? this contains only visual receptor cells and therefore, is the location of the most acute vision.
What is macula and fovea?
500
enable the eye to see at night
What are rods?
500
when the cornea is 45 degees the patient is said to have this type of astigmatism. The doctor would prescribe a cylinder lens having an axis placed at or near 135 degrees. this astigmatism seems to disturbs a patients vision more then the other two types.
What is an oblique astigmatism?
500
a condition in which there is a relative difference in size and/ or shape of the ocular images. An iseikonic lens is used to correct this
What is aniseikonia?
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