8 Explo Age-Related Changes in Astigmatism and Potential Causes Flashcards
causes deterioration of the retinal image and affects vision quality
Astigmatism
high degrees of astigmatism in childhood typically decreases with ___
Emmetropization
Common astigmatism in young adults
With-the-rule astigmatism
One of the main causes of deterioration of the retinal image in uncorrected and corrected eyes.
Astigmatism
Astigmatism can also lead to _____ in childhood
Amblyopia
Astigmatism is primarily caused by differential magnification in each ____ and _____
Principal meridian of the anterior corneal surface and internal optics
Several studies have reported a high prevalence and signi!cant degrees of astigmatism in?
Infants
Lower levels of WTR astigmatism are often observed in people older than the age of?
4 years
young adults aged 20 to 30 years have shown that ____ astigmatism is common in this age group
with the rule
Axis shifts from a predominance of WTR astigmatism to ___ astigmatism in adults older than 40 years old
Against the rule (ATR)
Refractive astigmatism increase with age after
50 years
Corneal astigmatism was found to be stable until the age of
80 years
Previous studies have suggested that astigmatism in infants may be caused by a
Steep cornea
Some reports have suggested that age-related changes in corneal physiology may influence the _______ and ______ of the cornea
Elasticity , rigidity
the mean radius, axial period, and intermolecular Bragg spacing of collagen !brils were greater in subjects older than _____ years than in younger adults
65
Changes in collagen fibrils may be the result of the
Glycation induced cross linking of collagen molecules
The ______ exerted on the cornea by the eyelids has been considered a potential factor in the development of corneal astigmatism
Pressure
Several studies have suggested that the tightness of the eyelids and the rigidity of the cornea interact to produce ________ and that the diminished eyelid tension caused by age-related ___________ may influence the cornea.
Astigmatism , dermatochalasis
the angle of the eyelid !ssure and the corneal cylinder axis and that the flattest corneal meridian tended to be ______ to the angle of the lower eyelid
Aligned parallel
The typical shift in the axis of astigmatism from WTR in young adults to ATR with increasing age was explained as a _______ with age, leading to a reduction in WTR astigmatism
Reduction in lid tension
The presence of a _______ in the eyelid has been shown to cause signi!cant changes in corneal topography and astigmatism and surgical removal can lead to resolution of the corneal changes.
Chalazion
patients with _______ have a higher degree of corneal astigmatism that seems to decrease after surgery.
Congenital ptosis
patients with blepharo- spasm found a reduction in WTR astigmatism from pretreatment levels 1 month after an injection of ________
Botulinum toxin type A
A gene that is strongly associated with the corneal curvature
PDGFRA gene
