Accommodation Flashcards
What is the definition of accommodation?
Changing of the refractive power of the lens in order to focus at different distances, with the amount needed relative to the distance of the target.
What might premature presbyopia be a sign of?
Poor general health
Glaucoma
What is accommodative insufficiency?
Unable to accommodate to the level needed, i.e. amplitude/near point abnormal for age
What are the possible aetiologies of accommodative insuffiency?
Uncorrected refractive error
Poor general health
Viral infection
Increase in close work
Rx drugs
How can accommodative insufficiency be managed?
Managing GH issues
Correct hyperopic refractive error
Orthoptic exercises if also convergence insufficiency
Miotics (less accomm needed if smaller pupil)
What is accommodative fatigue?
Accommodation tires after long periods of close work, but is usually ok
What are the possible aetiologies of accommodative fatigue?
Poor GH
Stress/tiredness
Excessive close work
Uncorrected RE
Hysterical reaction
How can accommodative fatigue be managed?
Rest
Treat GH
Correct refractive error
Orthoptic exercises if fusion/convergence poor
Temporary plus lenses
What is accommodative inertia?
Bilateral failure or delay in accommodation as fixation distance changes
What is the symptom of accommodative inertia?
Intermittent blurred vision- noticed when changing fixation distance
What can accommodative inertia be caused by?
Poor GH
Fatigue
Adies pupil
How should accommodative inertia be managed?
Correct refractive error
Improve GH
Improve fusion range and convergence - exercises (pen to nose, jump convergence, stereograms)
What is accommodative paralysis?
Complete inability to accommodate
What are the symptoms of accommodative paralysis?
Blurred near VA if not myopic
Photophobia due to lack of pupil constriction
Photopsia
Micropsia (objects appear smaller and further away)
Diplopia at near if no convergence
What are the possible aetiologies of accommodative paralysis?
Cycloplegics
Eye/head trauma
3rd nerve palsy
Space occupying lesion
General disease
How should accommodative paralysis be managed?
Treat the cause
Correct refractive error
Give reading add or prism at near if EXOT
Miotics
What is accommodative spasm?
Ciliary muscles unable to relax/cramped, causes continual accommodation and pseudo myopia
What are the symptoms of accommodative spasm?
Pseudomyopia
Headaches
Pain
Macropsia (objects seem larger and closer than they are)
Difficulty judging distance
What are the signs of accommodative spasm?
Divergence weakness or ESOP/T at distance
Miotic pupils
What are the possible aetiologies of accommodative spasm?
Uncorrected hyperopia
Control of distance EXOT with accommodation
Fatigue
Functional/emotional (no obvious clinical reason)
Cyclic ONIII spasm
Head trauma (often brainstem)
How should accommodative paralysis be treated?
Atropine 1%
Treat GH
Botox if convergence spasm associated
Stop close work
Temporary plus lenses
Refer to psychiatric services
What is a normal AC/A ratio?
3-5^:1D
What happens to AC/A ratio at presbyopia?
Slightly increases
What is the most accurate way of measuring AC/A ratio?
Gradient method
