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