Final Flashcards
Are most children born more myopic of hyperopic?
hyperopic
What causes a hyperopic shift in vision?
gradient index goes away (decreases spherical aberrations)
What is axial hyperopia due to?
short axial length
What is refractive hyperopia due to?
low power cornea
What is the type of hyperopia that cannot be overcome by accommodation?
absolute
What is the type of hyperopia that is within the range of accommodation?
facultative
What is the type of hyperopia that is concealed by a spasm of accommodation?
latent
What is the type of hyperopia that is revealed by routine refraction (dry)?
manifest
What is the type of hyperopia that is revealed by cycloplegic refraction?
wet
At what age does hyperopia increases for a second time?
about 55 years old
What symptoms worsen with near work for hyperopes?
- headache (frontal or occipital)
- asthenopia
- fatigue, sleepy
What are the unique aspects about hyperopic refractions?
- unstable retinoscopy
- monocular subjective usually takes least amount of plus correction
- binocular sphere check should take more plus than monocular
What are the common binocularity/cover test results for hyperopes +1.00 to +3.00 when uncorrected?
- often eso, distance and near
- high phoria with symptoms
- constant tropia with suppression with no symptoms
What are the common near test results for hyperopes +1.00 to +3.00 when uncorrected?
- BCC: variable, often high add
- NRA/PRA: NRA over +2.75
- dynamic: variable, high positive lag
What percentage of patients are over +3.00?
less than 3%
What are the common signs and symptoms of a over +3.00 hyperope?
- headache
- asthenopia
- strabismus more likely
- amblyopia more likely
- other developmental delays because motor development difficult
Where should you start for your retinoscopy for a hyperope?
make sure “E” is blurry before
If your patient is hyperopic and ortho or exo uncorrected, what should be watched for after correction is given?
high exophoria/exotropia
What are the drops given to children for a cycloplegic refraction? 1. Adults? 2
- cyclopentolate
2. two drops of 1% tropicamide
What is usually not rechecked while doing a cycloplegic refraction?
cyl
What is expected for a cycloplegic refraction of a hyperope? 1. What is this due to? 2
- +0.50 or more plus
2. latent hyperopia or loss of tonic accommodation
What is expected for a cycloplegic refraction of a myope? 1. What is this due to? 2
- +0.25 to +0.50
2. loss of tonic accommodation
What is expected for a cycloplegic refraction of a emmetrope? 1. What is this due to? 2
- +0.25 to +0.50
2. loss of tonic accommodation
If phoria is not a problem for the patient what should be prescribed to a hyperope relative to the manifest Rx?
+0.25 or +0.50 less than
If phoria is a problem for the patient what should be prescribed to a hyperope relative to the manifest Rx?
full Rx
What are common outcomes or steps to take when prescribing for a hyperope?
- full Rx may not be accepted unless takes steps over several glasses to get to full
- may only be useful at near
What is the most significant effect of a hyperopic Rx for a patient?
comfort
Why are a smaller eye size for glasses preferred for a hyperopic Rx?
- less weight
2. better cosmetic appearance
What is an average corneal curvature?
42.50
What percentage of Americans are myopic? 1. When does it usually present in children? 2. What gender is more likely to be myopic? 3
- 33%
- 8 to 11 years
- girls
What type of activities reduce the odds of developing myopia?
outdoor activities
What are the key features of myopia?
- distance blur, near clear
- longer axial length or higher corneal power
- high AC/A
- high accommodative lag
- accommodation may reduce due to misuse
- near phoria less exo when corrected
If you refract at a longer distance than you fit for glasses is the Rx over or under minused?
over (-)
At what Rx is the vertex distance essential and has a large impact on the glasses?
+- over 5D
What is the best way to measure the vertex distance?
with a distometer
What are the signs and symptoms of an over minused patient?
- headaches
- asthenopia
- esophoria
- blur on BI vergences at distance
- NRA over +2.75
When is the only time you would give less minus than their manifest Rx?
symptoms of over-minused
Is it easier for a child or an adult to reduce minus Rx because they are over-minused?
child
Why should progressive myopes never be under minused?
progress myopia faster
What is the reason for pseudomyopia?
ciliary muscle spasm so accommodation making an emmetrope or hyperope appear myopic
What is having different amounts of refractive error between the two eyes called? 1. When is it clinically significant? 2
- anisometropia
2. 1.00D sphere difference
What is having two different types of refractive error (ie myopia and hyperopia) between the two eyes called?
antimetropia
What might the signs and symptoms be for a patient with OD: -0.50 DS and OS: -3.00 DS?
- few complaints
- possible exo at near
- no stereo until corrected
What might the signs and symptoms be for a patient with OD: -0.50 DS and OS: +3.00 DS?
- few complaints, maybe some fog
- possible complaints at near
- amblyopia likely (OS suppressed)
What is it called when the patient cannot see well in one meridian?
meridional amblyopia
What percentage of the population has anisometropia? 1. At what age does it increase? 2
- 2 to 6%
2. 5 years
What can induce anisometropia? 1. What is the best way to correct this? 2
- refractive/cataract surgery
2. contact lens
What is a difference in image size due to correction called? 1. What are the symptoms of this? 2
- aniseikonia
2. nausea, dizziness, distortions
What are the possible causes of asthenopia of headaches in anisometropia patients?
- accommodation
- induced lateral and vertical prism
- aniseikonia
What are some key features that present in an anisometropia patient?
- amblyopia and/or suppression
- reduced stereo
- induced phoria, lateral or vertical
- asthenopia or headache
Are axial anisometropia patients better corrected with glasses or contacts?
glasses
What is important to tell the patient about using their glasses when they are anisometropes?
turn head, not eyes (helps avoid induced prism)
What does the use of contact lenses eliminate in anisometropia?
- aniseikonia
2. induced vertical or lateral prism of glasses
What are reasonable alternatives if an anisometropia patient is complaining of induced vertical prism with their bifocal?
- 2 Rx’s, one for distance and one for near
- CL and readers
- monovision CL’s
- slab off
What are ways to reduce induced vertical and lateral prism in a patient that still wants or needs to wear glasses?
- use small eye size
- fit Rx very close to eyes
- avoid progressive bifocals
What produces aniseikonia?
- correcting refractive anisometropia with glasses
- correcting axial anisometropia with CLs
- retinal stretching
What are the sources of total ocular astigmatism?
- corneal toricity (with the rule)
- lenticular toricity (against the rule)
- variations in refractive index of ocular media
- irregular foveal shape
What are the types of astigmatism?
- compound hyperopic
- compound myopic
- simple hyperopic
- simple myopic
- mixed
What does regular astigmatism refer to? 1. Irregular? 2
- meridians 90deg apart
2. meridians not 90deg apart
What does with-the-rule astigmatism refer to? 1. Against-the-rule? 2. Oblique? 3
- 180deg (vertical meridian steeper)
- 90deg (horizontal meridian steeper)
- 35/135deg
What percentage of the population has astigmatism? 1. Which type appears to be hereditary? 2
- 15-20% of population
2. high oblique astigmatism
What are the key symptoms of astigmatism?
- meridional blur
- monocular diplopia
- asthenopia
- headaches
What causes the headaches seen with astigmatism?
- fluctuations in accommodation
2. squinting of lids
What is the order from easiest astigmatism to see with to hardest?
- axis 180
- axis 90
- oblique axis
When is squinting to help eliminate astigmatism most useful?
axis 180
If visual acuity does not improve to 20/20+ after astigmatism corrected what should be considered?
- irregular astigmatism
2. meridional amblyopia
What should always be the first choice regarding children and their astigmatism?
full correction
What should be done to demonstrate the astigmatism that you will be giving a patient?
trial frame with patient walking around
What is a major benefit of contact lens correction for astigmatism?
full corrections without adaptation problems
When making a cut in cylinder power, what must also be adjusted?
sphere
If an astigmatic patient needs a movement in axis of the cyl, where should it move towards?
90 or 180 meridians