16 + 17 - intro to strab, case Hx and ref status

what is strabismus?

condition in which binocular fixation does not occur under normal viewing conditions

why diagnose and treat strabismus?

1. good functional vision

2. psychosocial aspects

3. protection of fellow eye

what are the psychosocial aspects of strabismus?

higher psychosocial and physical distress

more self-conscious about appearance

how did surgical correction affect psychosocial aspects of strabismus?

improvement in self-esteem, self-confidence and perceived intelligence

how did adult strabismus affect the ratings of official US army photographs?

estropia photos ranked significantly lower than orthophoric pictures

how does adult strabismus affect employment?

women with normal ocular alignment received better hiring preference scores than strabismic women

no difference between strabismic and non-strab men

how does childhood strabismus affect mental health and quality of life?

1. scored lower on health-related quality of life scales

2. more mental health problems

what are important case Hx questions to ask strabismic patients?

1. birth Hx

2. family Hx

3. onset

4. frequency

5. progression of deviation

6. previous Tx

7. symptoms → diplopia, headache, blurred vision, asthenopia, reduced depth perception

what birth Hx questions should you ask?

1. complications with birth

2. premature or full term

3. birthweight

4. APGAR

what should you ask about a preverbal child's case Hx?

1. mobility

2. head turn

3. eye rubbing

4. changes in visual behavior

why is correcting RE important in strabismics and amblyopes?

1. etiological factor in strab and amblyopia

2. easily done in primary care

what refractive error is a risk factor for exotropia?

1. astigmatism

2. anisometropia

what refractive error is a risk factor for esotropia?

uncorrected hyperopia

why is scoping on axis so important?

astigmatism increases with increasing eccentricity

sphere decreases with increasing eccentricity

how to scope strabismic patients?

1. put prism over fixating eye (align eyes)

2. perform retinoscopy outside phoropter

3. occlude as needed → be weary of acuity and fixation ability

what are the parameters of Mohindra retinoscopy?

monocular

dark room

50cm

patient fixates on light

how much do you subtract in Mohindra retinoscopy?

1.25 from sph

how do you use dynamic retinoscopy to assess refractive error?

use modified MEM to assess refractive error

what are the parameters of modified MEM?

50cm

have child look at you and neutralize reflex using loose lenses or lens bar

how much do you subtract in modified MEM?

YOU DON'T

what are cycloplegic agents MOA?

block acetylcholine → inhibit parasympathetic nerve impulses

what are the side effects of anti-cholinergics?

1. mad as a hatter

2. blind as a bat

3. red as a beet

4. dry as a bone

5. hot as a hare

what cycloplegic agents can we use?

tropicamide (4-6 hours)

cyclopentolate (up to 24 hrs)

atropine (7 days or longer)

how much cyclopentolate should you use? percentage for per age?

2 gtts

1% for children ≥ 1 year

0.5% for children < 1 year

when to cycloplege?

1. strabismus and amblyopia → standard of care

2. hyperopes → latent, high esophoria, lag of accommodation

3. VA problems/symptoms inconsistent with ManRx

4. 1st time pt

5. uncooperative

is it okay to use tropicamide as a replacement to cyclopentolate to cycloplege?

yes → if only have available

what is the difference in amblyopic subjective refraction?

may have a larger just noticeable difference than typical 0.25 D