Prelim And Mid term Exam Flashcards
A type ametropia where the cornea and crytalline lens have incorrect power
REFRACTIVE AMETROPIA
A TYPE OF AMETROPIA WHERE LIGHT PASSES THROUGH THE DIFFERENT MEDIA OF THE EYE FORMING A FOCAL POINT BEHIND IN THE RETINA
HYPEROPIA
A TYPE OF ASTIGMATISM WHERE BOTH FOCAL POINTS BEHIND THE RETINA
Compound hyperopic astigmatism
A TYPE OF ASTIGMATISM WHERE ONE FOCAL POINT IS ON THE RETINA and the other is in front of the retina
SIMPLE MYOPIC ASTIGMATISM
It is a process where the powers Of the eyes refracting components adjust to compensate the child growth
EMMETROPIZATION
ANOTHER TERM OF PRESBYOPIA
Short arm syndrome
AT WHAT AGE DOES PRESBYOPIA USUALLY OCCUR
40 Years old
A VISION TEST that determines your best visual acuity with corrective lenses lenght
COMBINED AXIAL AMETROPIA
Give atleast 2 optometric managements for presbyopia patients.
READING EYEGLASSES, REFRACTION, VISION TESTING, CONTACTS AND SURGERY
AT WHAT AGE DOES A CHILD HAVE 20/20
3 yrs old
At what age does the child’s accommodation develop with good visual acuity
3 yrs old
A REFRACTIVE ERROR WHERE THE INCIDENT RAYS OF LIGHT DO NOT COME TO A FOCUS ON THE RETINA
AMETROPIA
At birth the eyes are not _________
with each other but act as _______ _______sense organs
Associated
Two independent
In new born first sign of the development of _______ appears when the eyes________
Fixation reflex
Follow the light
At the age of ________ the eyes follow large object
2 months
The foveas are not fully formed until the _______ of life
3rd month
At _____ months they hold object
3 months
At the age of _____ fixates at an Object for one or two minutes
6 months
At birth vision is no greater than 5/200 (Subnormal Va) the eye is Normally _______because the ______are not fully developed
HYPEROPHIC
CILIARY MUSCLE
At the age of 20/70
1 yr old
At the age of 20/20
3 yrs old
Becomes fully developed from one to one and half years of life
Fusional mechanism
Accomodations Develops with sharpening of visual acuity at the age of
3 yrs old
At 3 months of age the eyes start to follow large objects
2months-False
At the age of 6months the child fixates at an object for one and two minutes
True
Emmetropia is a refractive status where light coming from infinity passes through the different media of the eye forming a circle of least confusion in front of retina
False
Ametropia is a refractive status where light coming from infinity passes through the different media of the eye forming a circle of least confusion on the retina
False
Full term baby born has a high incidence of myopia
False
HYPEROPIA is a rare birth
False
Static refraction is used to determine the power of the eye through the different media of the eye forming at least 2 focal points called presbyopia
False
Lasik means
Laser assisted in situ keratomileusis
LASEk MEANS
Laser subepithelial keratomileusis
PRK
Photorefractive keratectomy
ISCR
Intrastroma corneal ring
Icr
Intra corneal ring
Phakic IOL’S
Phakic intraocular lenses
Rk
Radial keratotomy
-For high degree of myopia (up to 20D)
-THE EPITHELIUM IS REMOVED AND THEN A POCKET IS FASHIONED UNDER THE EDGE OF THE REMAINING EPITHELIUM & INTO THIS IS INSERTED THE CRYOLATHED DONOR HOMOGRAFT.
-preserved material can also be used
EPI-KERA-TO-PHAKIA
-short sightedness
-myopia is a greek word “close the eyes”
-parellel rays of the light coming from infinity are focused in front of retina
ACCOMMODATION IS AT REST
MYOPIA
Mechanism of production
Axial
Curvatural
Index
Myopia due to excessive accommodation
OPTICS OF MYOPIA
-Far point in finite
-emmetropic eye is infinity
-higher myopic the shorter the distance
-if far point is 1METER there is 1 DIOPTER OF MYOPIA
Accommodation need not develop normally resulting in
Convergence insufficiency EXOPHORIA
TYPES OF CLASSIFICATION
Clinical classification
Degree of myopia
Age of onset
DEGREE OF MYOPIA
Low myopia (<3 d)
Medium myopia (3-6d)
High myopia (>6 d)
AGE OF ONSET
-Congenital myopia
-young onset myopia (20 yrs old)
-early adult onset myopia(20-40yrs old)
Late adult onset myopia (>40 yrs old)
CLINICAL CLASSIFICATION
Congenital myopia
Simple myopia
Nocturnal myopia
Degenerative myopia
Pseudo myopia
Induced myopia
-Premature babies
-marfan syndrome
-increase axial length
-increase overall globe size
-since birth diagnosed 2-3 yrs
-if unilateral as anisometropia it may develop amblyopia, strabimus.
-usually 8d-10d remain constant
-bilateral difficulty in distant vision hold things
Congenital myopia
Associated condition
-Convergent squint
-cataract
-aniridia
-megalocornea
Associated condition management
Early correction is desirable
Early full correction desirable
Poor prognosis
-Physiological error not associated with any disease of the eye
Etiology:
- normal biological variation in development of eye
-inheritance
Simple myopia
Associated factors of simple myopia
-Role of diet
Clinical picture
-rarely present at birth
-rather born hypermetropic,become myopic
-begin 7-10 years stabilizing around mid teens
-usually around 5D never exceeds 8D
Symptoms of simple myopia
-poor vision for distance
-convergence weakness,exophoria,suppression
-excessive accommodation inducing ciliary spasm and artificially increasing the amount of myopia
-psychological outlook
Sign of simple myopia
-large prominent
-deep anterior chamber
-usually doesn’t exceed 6-8D
-normal fundus rarely crescent
Rapidly progressive associated with changes in the eye
Pathological degenerative myopia
Growth of the eye ball outside the normal biological variations of development
Rapid axial
Etiology of pathological degenerative myopia
Rapid axial growth
Rapid of hereditary
Role of growth process
Genetic factors- general growth process
More growth retina
Stretching sclera
Increase axial length
Degenerative of choroid
Degenerative of retina
Degenerative of vitreous
Symptoms of degenerative myopia
-Defective vision
-muscae volintates/ floating black opacities
Another term of floating black opacities
MUSCAE VOLITANTES
Eye large prominent eyes stimulating
EXOPHTHALMOS
_____ show opacities at the posterior pole due to aberration of ________ ________ may also occur
LENS
OVERSTRETCHING ANTERIOR DISLOCATION
Vitreous degeneration,vitreous liquefaction, vitreous detachment present as
Weiss reflex
Sclera thinning resulting in formation of
STAPHYLOMA
Visual field defects show contraction and in some ring present
SCOTOMAS
Myopic crescent situated nasally and supertraction of the retina temporally
Inverse crescent
Myopic crescent
-retinal detachment
-posterior staphyloma
-retinal holes
-tesselated fundus
-macula foster musch flesk
3 crescent
Myopic crescent
Supertraction of the retina
Choroid crescent
Optical treatment
-Appropriate concave lenses
-minimum acceptance providing maximum vision
Defect should never be overcorrected and advised for constant use to avoid squinting and develop a normal accommodation convergence reflex
LOW DEGREES OF MYOPIA (UP TO -6D)
IN YOUNG SUBJECTS
RECEIVING SPECTACLE FOR THE FIRST TIME HAVE CILIARY MUSCLE THAT ARE UNACCUSTOMED TO ACCOMODATE EFFIENCTLY SO THAT LENS OF SLIGHTLY POWER 1 OR 2 D MAY BE PRESCRIBED FOR READING ESPECIALLY IF ENGAGED IN TO ANY GREATER EXTENT. ABOVE THE 40YRS WHEN ACCOMMODATION FAILS PHYSIOLOGICALLY A WEAKER GLASS FOR NEAR WORK IS ESSENTIAL
Low degrees of myopia up to -6d
In adults
-involves direct laser ablation of corneal stroma after removal of corneal epithelium mechanically or using a laser beam
- FOR MYOPIC A LARGE AMOUNT OF ABLATION IS DONE IN CENTRAL CORNEA THAN IN THE PERIPHERY
-give good results for 2D TO 6D OF MYOPIA
PHOTOREFRACTIVE KERATECTOMY
Lasek indications
Low myopia
Irregular astigmatism
Thin corneal pachymetry
Glaucoma suspect
Method can be used to correct both myopia and hypermetropia
Phakic intraocular lenses
Phakic IOL TYPES:
Pc iol
Angle supported iol
Iris claw lens
It results in a vaulting effect that flattens the central cornea decreasing the myopia
INTRA CORNEAL RING IMPLANTATION
These incision healing flatten the central cornea thereby reducing its refractive power
RADIAL KERATOTOMY
Types of ametropia
Myopia
Hyperopia
Astigmatism
Astigmatism can be detected and measured with
Refraction
Vision testing
Corneal topography
Keratotomy
