CS Final
What are the abnormalities in anatomic structures that look like strabismus
-Craniofacial -pseudostrabismus (hypertelorism-80 mm between the two bony orbits) - appear exotropic -Large wide nasal brisge or epicanthal folds - appear isotropic
This is the most common strabismic deviation, usually presents during early life -usually stable and consistent -most are unilateral -may be due to RE -frequently larger at near -common cause of amblyopia
-Esotropia
How does an anesthetic work on the eye?
-blocks sensation on the ocular surface -by blocking the sodium influx, can not send signal that something is touching the eye
Ret reveals 3D of hyperopia, pt can only relax 2D on the subjective. what is the manifest and what is the latent?
-manifest: 2D -Latent: 1D
What are the causes of amblyopia?
-nerve pathway does not develop from one or both eyes -brain ignores the image from the weaker eye
Adverse effects of anesthetic
-punctate keratitis -corneal edema -conjunctival hyperemia -stinging/lacrimation -delayed corneal healing -unstable tear film -decreased reflex tearing -reduced blinking, increased evaporation -toxicity of endothelium and epithelium -microbial contamination- if it touches someone's eye
What dose of atropine are most common in the drops and ointment
1% drop 0.5% ointment
What are the 3 ways to residual accommodation
1. Pascal's Method 2. Duane's 3. Yasuna's*
Which dose of phenylephrine will we use
2.5
What is the lethal dose of atropine?
20 drops of 1% for children 160 drops of 1% adults
If the pt is adequately cyclopleged what will the minimum residual accommodation =
2D or less
OTC and rx medicaitons account of ____% of acute angle-closure galucoma
33%
How does pH effect anesthetic drops?
Acidic pH makes it less effective 9this can happen when a pt has an infection
This is an acquired unilateral or bilateral decrease of VA for which no obvious structural or pathologic causes can be detected by physical examination of they eye
Amblyopia
If there was a young esotropic patient what would be the drug of choice?
Atropine -1% TID for 3 days before appt or 1% ointment (less side effects) BID for 3 days before
What is aniseikonia?
Binocular condition of unequal image sizes cannot be fused
what is the relationship between cycloplegics and glaucoma
Cycloplegics rise IOP especially in glaucoma pts
In strabismus, is eso or exo more prevalent?
Esotropia
What is the direction of adolescents to adult strabismus?
Exotropia
the amount of hyperopia that can be overcome by accommodation
Facultative
This strabismus is the most complex, least understood, and usually includes: -abnormal accommodative convergence -weak fusional ability - excessive or insufficient tonic innervation to the EOMs -Inadequate or excessive central coordination from the brain
Innervational Strabismus
This is the amount of hyperopia that cannot be readily relaxed in routine refractive exam
Latent -must cycloplegia patient to find it
the patient cannot help but compensate for by accommodation (increased tonicity of the ciliary muscle)
Latent hyperopia
If they can only see the R on the R+L which eye are they suppressing?
Left
this is the hyperopia that can be seen with a subjective refraction
Manifest
this is the amount of hyperopia that can be measured by relaxation of accommodation with plus lenses
Manifest -amount found in traditional dry refraction
green cap
Miotics (constricts pupil)
pt has a square pupil, should you dilate?
NO it will fall
In the worth 4 dot if they see 3 green dots they are suppressing
OD
In the worth 4 dot, if they see 2 red dots they are suppressing
OS
What are the drugs that inhibit the cholinergic division of the autonomic nervous system
Parasympatholytics - tropicamide and atropine -inhibits accommodation, iris sphincter -ex/ tropicamide and atropine
this is a disorder in which the two eyes do not line up in the same direction, they do not look at the same object at the same time
Strabismus
These are dilators that stimulate the adrenergic division of the autonomic system and increases pupil size. pupils are still able to react to a bright light
Sympathomimetics -Phenylephrine -Hydroxyamphetamine
t/f cyclopentolate is better than homatropine at cycloplegia
T
Why do people faint with dilation ?
The vagus nerve is over-stimulated can happen also with: -CL insertion -Applanation tonometry -Gonioscopy -Punctal Plug insertion/removal -foreign body removal
t/f anesthetics decrease blink rate and tearing and roughen the corneal epithelium to increase drug penetration
True
What is a peripheral iridotomy?
a laser procedure opens a narrow or closed angle between the cornea and iris; this closed angle interferes with the drainage of fluid. The doctor will make a small hole in the iris, allowing fluid to flow more freely in the eye.
If esotropia occurs late it may be due to
a lateral rectus palsy
cycloplegia is
blurred vision at near due to paralysis of ciliary muscle *loss of accommodation* lens cannot be adjusted to focus
Examples of ester anesthetics
cocaine, procaine, proparacaine, tetracaine, benzocaine -what we will use
this is the amount of hyperopia that cannot be
compensated for by accommodation
mydriasis is
dilated pupil -by dilator contraction or sphincter relaxation
More temporal hirshberg represents
esotropia
Uncorrected hyperopia can be associated with
esotropia
What is the direction of strabismus in early childhood
esotropia-due to high tonic convergence
more nasal hirshberg represents
exotropia
this accommodation can (at will) be compensated for by accommodation
facultative
What is the only time you would give 2 drops of tropicamide
for cycloplegic refraction only
In the worth 4 dot if they see 4 dots pt is
fusing, all okay
How does tropicamide work?
inhibits the PARAsympathetic pathway to inhibit constriction -parasympatholyitc
Why would you not want to put a mydriatic in an infants eye
it stops their digestion
when all or part of their hyperopia is compensated for by the tonicity of the ciliary muscle, this is
latent hyperopia
Examples of the amides
lidocaine and bupivacaine
Where should you place an eye drop?
lower cul-de-sac pf conjunctiva -DO NOT place drop on the cornea
total hyperopia =
manifest + latent
red cap
mydriatics and cycloplegics
Which refractive error is the atropine drops for
myopia -need a VERY low concentration because atropine is SO strong and can cause the biggest effects
In Duane's method the difference between the near blur point and the far blur point is the
residual acc
The Yasuna method the dioptric difference (absolute value) is equal to the
residual accomm
How does phenylephrine work?
stimulates the sympathetic pathway to increase dilation
In the worth 4 dot they see 5 dots what is with the patient?
they have double vision
clear/white cap
topical anesthetic
What is ansiometropia?
unequal refractive error