Ninos Flashcards
Bruckner test
Semi dark room with direct ophthalmoscope to assess red reflex in both eyes from 1 m away
Medial Rectus
Action:
Insertion : 5.5 mm from limbus
Innervation: Lower CN III
Blood supply: : medial muscular branch of ophthalmic artery
Lateral Rectus
Action:
Insertion : 6.9 mm from limbus
Innervation: Lower CN VI
Blood supply: lateral muscular branch of ophthalmic artery, also partially lacrimal artery
Superior Rectus
Action:
Insertion :7.7 mm from limbus
Innervation: Upper CNIII
Blood supply: lateral muscular branch of ophthalmic artery
Forms an angle of 23 degrees with visual axis or mid plane
Inferior Rectus
Action:
Insertion : 6.5 mm from limbus
Innervation: Lower CN III
Blood supply: medial muscular branch of ophthalmic artery , partially infraorbital artery
Forms an angle of 23 degrees with visual axis of midplane of eye in primary position
Superior Oblique
Action:
Insertion : posterior to equator
Innervation: CN IV
Blood supply: lateral muscular branch
Inferior Oblique
Action:
Insertion : lateral to macula
Innervation: Lower CN III
Blood supply: : medial muscular branch of ophthalmic artery, partially infraorbital artery
Levator
Action:
Insertion : pretarsal obicularis
Innervation: Upper CN III
Blood supply: lateral muscular branch of ophthalmic artery
EOM structure
Nerve fibers to muscle fibers : 1:3 to 1:5
Outer orbital layer and inner global layer
Sherringtons Law
Increased innervation of a given EOM is accompanied by a reciprocal decrease in the innervation of its antagonist
Herings Law
When the eyes move into a gaze direction, there is a simultaneous and equal increase in innervation of the yoke muscles for that direction.
AC/A ratio
Accommodative convergence / accommodation
AC/A
Development
Between 8 and 15 weeks, there are 2-2.5 million retinal ganglion cells
Monofixation Syndrom
Presence of peripheral fusion but absence of bifoveal fusion due to a central scotoma
Often with esotropia
Any amount of gross stereopsis confirms presence of peripheral fusion
Anomalous Retinal Correspondence
Fovea of fixating eye is common with peripheral area of other eye
Paradoxical diplopia of ARC persists after strab surgery
Refractive Amblyopia
- 50 D if anisohyperopia
- 00 D anisoastigmatism
- 00 of anisomyopia
Hyperopia over 4-5 D
Myopia over 5-6 D
Astigmatism of 2-3 D of cylinder
Deprivation Amblyopia
Unilateral 6 weeks
Bilateral 10 weeks
Hirschberg Test
22 prism D of per millimeter of decentration
Krimsky is with prisms
Angle Kappa
Positive angle kappa is exotropia
Negative angle kappa is esotropia
Causes of overelevation in Adduction
Inferior oblique overaction - v pattern , weaken IO
Dissociated vertical deviation
Large angle glaucoma
Rectus muscle pulley heterotopia
Orbital dysmorphism
Duane
Anti elevation syndrome after CL inferior oblique anterior transposition
Contralateral inferior Rectus muscle restriction
Skew deviation
Causes of Overdepression in Adduction
Superior oblique muscle - Lower eye has overaction, weaken SO
Large angle exotropia
Rectus muscle pulley heterotropia
Orbital dysmorphism
Brown syndrome
Contralateral superior Rectus muscle contracture
Skew deviation
Superior Oblique Palsy
Inferior Oblique Palsy
Unilateral
Bilateral with V pattern
Masked
Treat with prism or weaken IO or strengthen SO
IO Palsy: hypotropia when addicting , A pattern , intorsion and head tilt. Negative forced duction. Weaken same SO or other SR.
Vertical Deviations with Horizontal Comitance
Monocular elevation deficiency: hypotropia that is similar in adduction and abduction
1 restriction of IR
- Deficient innervation of elevators
- Combo
Tx with Knapp
Floor fracture, partial CN III Palsy , TED, tumor, fibrosis
Dissociated Vertical Deviation
Either eye slowly drifts upward and outward when not stimulated
Measure with base down prism in front of upward deviant eye when occluded, then switched
SR recession or IR resection
Duane Retraction Syndrome
Anomalous co contraction of LR and MR
- Poor abduction with eso in primary - MR recession
- Poor adduction with exo in primary - LR recession
- Both
Other syndromes
Congenital fibrosis : strabismus fixus is horizontal, vertical retraction is SR
Mobius: 6th and 7th Nerve palsies ; if kind with exotropia and vertical limitation = TUBB3
Brown: deficient elevation in adduction + forced ductions and V pattern
CPEO: progressive ptosis to paralysis.
Convergence Insufficiency
Asthenopia
Reading problems
Blurred near vision
Diplopia