Random Questions Flashcards
A 23-year old female is seen at your office with concerns of eye fatigue, diplopia and headaches after 30 minutes of computer use. Her subjective refraction is +0.25 D OU. Her near point of convergence is 15 centimeters. What is the most likely diagnosis based solely upon this information?
Convergence insufficiency
- receded NPC
- diplopia generally absent in latent hyperopia
Convergence Insufficiency
- AC/A?
- accommodation?
- PRA/NRA?
- vergences?
- exophoria greater at near than distance
- low AC/A ratio
- receded NPC
- normal accommodation
- low NRA
- low BO vergence ranges
NPC break and recovery?
5 cm // 7 cm
Tip: red/green glasses will make the system more fragile
Pseudoconvergence insufficiency
- receded NPC
- accommodative insufficiency, not convergence problem
How to differentiate pseudo CI vs real CI?
Use +2.00 lens in front of patient.
True CI will have difficulty, pseudo will not because the lens makes up for the insufficient accommodation.
Sheard’s Criterion
2/3(phoria) - 1/3(compensating vergence)
Training for… convergence insufficiency?
- VT
- if no improvement, prescribe BI prism based on Sheard’s
Training for… convergence excess?
- plus lens at near
- VT or prism as needed
Training for… divergence insufficiency?
- BO prism at distance
- then VT
- refer if neurological
Training for… divergence excess?
- VT
- prism or minus lenses
Training for… Basic Exo?
- BI prism, VT
Training for… Basic Eso?
- BO prism, VT
Training for… vertical imbalance?
- prism
Insufficiencies have (high/low) AC/As
LOW!
Excesses have (high/low) AC/As
HIGH!
What can you do for antisuppresion therapy?
- increase illumination
- movement
- blur nonsuppressed eye
- increase contrast for suppressed eye
What is Hering’s Law?
Hering’s law of equal innervation is used to explain the conjugacy of saccadic eye movement in stereoptic animals. Yoked movement.
Eccentric Fixation
Monocular phenomenon where a non-foveal area is used to fixate.
Bruckner Test
Use ophthalmoscope at 80-100cm to assess red reflex.
Bruckner Test - Inferior Crescent
MYOPIA!
Bruckner Test - Fixating eye reflex
Darker!
CN 1
Olfactory
- smell
CN 2
Optic nerve
- vision
CN 3
Oculomotor nerve
- innervation to SR, IR, IO, MR, iris sphincter, ciliary muscle, levator
CN 4
Trochlear nerve
- innervate SO
CN 5
Trigeminal nerve (V1 - opthalmic, V2 - maxillary, V3 - mandibular)
- corneal and facial sensation (sensory)
- motor to muscle mastication
CN 6
Abducens nerve
- innervates lateral rectus
CN 7
Facial nerve
- facial motor function, taste to anterior 2/3 tongue, lacrimation + salivation (parasympathetic innervation)
CN 8
Vestibular
- hearing and equilibrium
CN 9
Glossopharyngeal
- taste posterior 1/3 of tongue
- sensory from carotid sinus
- motor innervation pharynx
CN 10
Vagus nerve
- decrease heart rate
- carries sensory info from esophagus, respiratory tract and abdominal viscera
CN 11
Spinal accessory nerve
- motor innervation to trapezius, sternocleidomastoid and muscles swallowing
CN 12
Hypoglossal
- motor to tongue
Bilateral INO
Associated with multiple sclerosis
Internuclear ophthalmoplegia (INO)
When gaze is made contralateral to the affected eye, limited adduction occurs. Contralateral eye will move laterally but have nystagmus.
“The disorder is caused by injury or dysfunction in the medial longitudinal fasciculus (MLF), a heavily myelinated tract that allows conjugate eye movement by connecting the paramedian pontine reticular formation (PPRF)-abducens nucleus complex of the contralateral side to the oculomotor nucleus of the ipsilateral side.”
Congenital nystagmus characteristics
- binocular
- conjugate
- associated
- no oscillopsia
- damped by convergence
- superimposed latent nystagmus
- abolished in sleep
- nystagmus direction same in all positions
Conditions associated with congenital nystagmus
- ocular albinism
- aniridia
- congenital optic nerve disease
- achromatopsia
When a patient has a right head turn, diplopia is worse on (right/left) gaze?
Right gaze!
Because with a right head turn, patient is looking left.
A patient with a 4 prism diopter right hyperphoria has 5/3 right supravergence and 4/2 right infravergence. What is the correctinve prism needed?
0.5 base down over right eye.
Formula:
Base-down to break MINUS base-up to break / 2
(+) BD, (-) BU
Compensating vergence for hyperphoria?
Infravergence.
Assessed with base-up prism.
Oculogyric crisis
Oculogyric crisis refers to spasms of extraocular muscles leading to tonic eye deviation (usually upward), with each spasm lasting from seconds to several hours; the entire episode may last up to several weeks or months.
