Accommodative Anomalies Flashcards
what is accommodative insuffiency
Near point of accomm consistently below that expected for age and refractive error.
Usually bilateral
Symptoms/findings:
Blurred vision at near
Reduced NPA (unioc & binoc) for age
Increased accomm lag (dynamic ret)
Micropsia (rare illusion in severe cases)
Effort might produce: eso deviation
what is accommodative fatiuge
Accomm is initially sufficient but reduces with continued exertion
Bilateral
Symptoms/findings:
Blurred vision at near
Occur with prolonged near work & can be relieved by rest
Reduced NPA on repeated testing (unioc & binoc)
Increasing lag of accomm (dynamic ret)
Micropsia (rare)
what is accommodative inertia
Difficulty in altering accomm - delay in either exerting or relaxing accomm
Bilateral
Symptoms/findings:
Blurred vision when changing focus/distance
Possibly normal NPA and normal lag accomm
Poor accomm facility
Worse in poor illumination
what is accommodative paralysis
Inability to exert any accomm
Unilateral or bilateral
Symptoms:
Increasing blurred vision as fixation moves from infinity towards patient
micropsia
Photophobia (if pupil dilated)
Diplopia (if convergence paralysis too)
Signs: Dilated pupil (depending on aetiology)
Unable to measure NPA and lag/lead accomm
what are the causes of accommodative paralysis
whiplash , trauma , side effects of meds caution 3rd nerve plasies, midbrain disorder , conditions affecting the nervous system
causes of accommodative inertia
newly corrected refractive error
disease accomodation
ocular health
general health
whiplash
trauma
early presbyopia
what are the causes of accommodative fatigue
newly corrected refractive error
ocular health
general health
how to drugs/ medication affect accomodation
These may cause reduction in accommodation:
Anticholinergics
e.g. Scopolamine patch used for motion sickness, nausea & vomiting
Firth and Walker (2006) reduced accomm – used to reduce drooling in children with disabilities
Neuroleptics & antipsychotics
e.g. Phenothiazines
Used in schizophrenia
Reduce accomm by 40-100% (Thaler, 1979)
Bladder spasmolytic drugs
e.g. Propiverine – reduces accomm in children if high dose (Arfwidsson, 2007)
what types of drugs/ medication cause a reduction in medication
These may cause reduction in accommodation:
Antihistamines
Allergy meds, long term use
Antidysrhythmic drugs
e.g. Cibenzoline
Restore normal heart rhythm and conduction
Severely decreased accomm (Frucht et al 1984)
Tricyclic antidepressants
e.g. Lorazepam (Jung et al 2012) – although Speeg-Schatz et al (2001) found it affects convergence but not accomm
Important to ask about meds and be aware this could reduce accomm
how are accommodative anomalies managed
Correct refractive error
Treat any underlying cause
Orthoptic accommodative exercises
Near point accomm – accomm push up, reverse dot card
Jump exercises
Accomm facility (Sterner et al 2001)
Emphasise CLEAR rather than SINGLE vision
Simple conv exercises more effective at improving accomm than accomm exercises (Horwood & Toor 2014; Horwood et al 2014)
Plus correction for near work (if no response to Tx)
Wahlberg et al 2010 suggests +1DS instead of +2DS
?counselling/ referral to clinical psychologist
Functional
Dynamic retinoscopy
how to manage accommodative parlaysis
Not able to exercise
Treat cause (if possible)
Correct any refractive error
Prescribe reading addition (+ lens)
Painted CL if pupil dilated
Counselling/ referral to clinical psychologist
Base in prism (if convergence paralysis too)
Miotics (e.g. Pilocarpine) rarely given
Reduce accomm effort needed for clear image
how to manage accommodative spasm
Excessive accomm
Nearly always accompanied by conv spasm
Symptoms:
Blurred vision
Diplopia
Macropsia
Signs:
Miosis
Variable ET - assoc with excessive conv
Spasm on lateral gaze gives appearance of LR palsy
Pseudo myopia
Accomm lead (dynamic ret)
how to treat accomodative spasm
Observe patient throughout testing
Observe consistency of miosis, convergence spasm
Test abduction (may need to use doll’s head)
Cycloplegic refraction
NB Acute myopia can be an adverse reaction to some drugs (e.g. Topiramate – epilepsy/migraines). There is no miosis and no convergence spasm
what are the causes of accommodative spasm
Functional
Uncorrected hypermetropia
Lack of relaxation after close work (mild)
Manipulation of accomm to control ocular alignment
Closed head trauma
Rostral midbrain lesion
Increased intracranial pressure (single report Kawasaki & Borruat 2005)
what drugs can cause accommodative spasm
Drugs
Parasympathomimetics e.g. pilocarpine – used to treat glaucoma
Anticholinesterase agents
Pula et al (2013)
Lit review of systemic meds which result in neuro-ophthal side effects (includes accomm) and provides some info on why these occur
what is the management of accommodative spasm
Correct refractive error
Re-assure and visual rest – do nothing! Will resolve if no underlying neurological disease
If it is a child – tell the parent to stop asking about it
Cycloplegics with reading correction
…miotics…saline (placebo)
When combined with convergence spasm BT to medial recti
Consider counselling / clinical psychologist – if needed to remove the stress factor
what is accomodation also considered in
Premature presbyopia
Computer Vision Syndrome (CVS)
Special needs children:
Cerebral palsy
Downs syndrome
what is premature presbyopia
Typically, onset of symptoms between 40-50 years age
May purely reflect extremes of normal or be due to nutritional, environmental, or disease-related causes
Sunlight (ultraviolet radiation) – premature degradation of crystalline lens (Priyambada, 2019)
Tobacco users (Fasih et al, 2014)
Diabetes, AIDS
Plus/reading glasses
what is computer vision syndrome
Term used for complaints of computer users which include: eyestrain, eye fatigue, burning sensations, dry eyes, irritation, redness, blurred vision, delay in focusing, diplopia
what do blue light filterr use
Excessive exposure to intense light, incl blue light, from screens may result in CVS
Blue light filter gls available to relieve symptoms
No sig effect on tear production and dry eyes but patients did report a sig improvement in comfort (Cheng et al 2014)
Improvement in symptoms but not sig (Dabrowiecki et al 2019)
‘The best scientific evidence currently available does not support the use of blue-blocking spectacle lenses’ (College of optometrists 2018)
how to manage computer vision syndrome
Treat any apparent accomm or conv anomaly
Ensure refractive correction for dist of monitor (‘middle distance’)
Blinking
Take rest breaks
Rosenfield (2011) review
how is accomodation linked to cerebral palsy
42% children have poor accommodation (Leat, 1996)
Greater accommodative lag in those with more severe motor impairments (McClelland et al, 2006)
Near pupil response found to be a ‘useful indicator’ of accommodative response with 83% sensitivity and 72% specificity (Saunders et al, 2008)
i.e. 17% defect missed
28% normal but thought to be defective
how is accomodation linked to downs syndrome
Accommodation reduced
80% children with Down’s had reduced accommodation c/w controls (Woodhouse et al, 1993)
Less accurate (Anderson et al, 2011)
Under accommodation more likely where hypermetropia present and strabismus present (Stewart et al, 2007)
Bifocals suggested
Improved accuracy in accommodation (Stewart et al, 2005)
Literacy skills improve faster (Nandakumar et al, 2011)
