Accommodative Anomalies Flashcards
What are some examples of accommodative anomalies and are they defective or excessive?
Defective:
- Accommodative Insufficiency
- Accommodative Fatigue
- Accommodative Paralysis
- Accommodative Inertia (failure to alter)
Excessive:
- Accommodative Spasm
What is the definition of Accommodative Insufficiency?
Near point of accomm consistently below that expected for age and refractive error.
Usually bilateral
What are the Symptoms/Findings of Accommodative Insufficiency in relation to:
- Near vision?
- Uniocular and binocular - NPA?
- Dynamic ret?
- Deviation?
- Micropsia?
- Near Vision
Blurred - Uniocular & Binocular NPA
Reduced for Age - Dynamic RET
Increased Accommodative Lag - Deviation
Effort might produce Eso - Micropsia
Rare illusion in severe cases
What is Accommodative Fatigue?
Accomm is initially sufficient but reduces with continued exertion
Bilateral
What are the Symptoms/Findings of Accommodative Fatigue in relation to:
- Near vision?
- Uniocular and binocular - NPA?
- Dynamic ret?
- Micropsia?
- When does it occur?
- Near Vision
Blurred - Uniocular & Binocular NPA
Reduced on repeated testing (unioc and binoc) - Dynamic RET
Increasing lag of accommodation - Micropsia
Rare - When does it occur?
With prolonged near work, can be relieved by rest
What is Accommodative Inertia?
Difficulty in altering accomm - delay in either exerting or relaxing accomm
Bilateral
What are the Symptoms/Findings of Accommodative Inertia in relation to:
- Blur
- Uniocular and binocular - NPA?
- Dynamic RET
- Accommodative Facility
- Blur
When changing focus/distance - Uniocular and binocular - NPA?
Possibly normal - Dynamic RET
Possibly normal accommodative lag - Accommodative Facility
Reduced
Worse in poor illumination
What is Accommodative Paralysis?
- Inability to exert any accomm
- Blurred vision for all distances closer than infinity*
- Unilateral or bilateral
What are the Symptoms/Findings of Accommodative Paralysis in relation to:
- Blur
- Uniocular and binocular - NPA?
- Dynamic RET
- Micropsia
- Pupils
- Photophobia
- Diplopia
- Blur
Increasing blur as fixation moves from infinity towards patient - Uniocular and binocular - NPA?
Unable to measure - Dynamic RET
Unable to measure - Micropsia
Present - Pupils
Possibly dilated (depending on aetiology) - Photophobia
If pupil dilated - Diplopia
If convergence paralysis present too
What is Macropsia?
- Objects appear larger than natural size.
- When there is an excess of accommodation, reduced effort or no effort is required to focus on a near object.
- The brain interprets the near object producing the retinal image as being further away.
- The near object is judged to be a larger than normal object in the distance.
What is Micropsia?
- Objects appear smaller than natural size.
- In a defect of accommodation, excessive accommodation is required to focus on a near object.
- The brain interprets the retinal image as produced by an object close to the eye.
- The object is judged to be smaller than its natural size
What drugs/medication can cause accommodative deficiency?
- Anticholinergics
- Neuroleptics & antipsychotics
- Bladder spasmolytic drugs
- Antihistamines (long term use)
- Antidysrhythmic drugs
- Tricyclic antidepressants
Important to ask about meds and be aware this could reduce accommodation
What are Anticholinergics?
e.g. Scopolamine patch used for: motion sickness, nausea, vomiting
Or used to reduced drooling in children with disabilities
Firth and Walker (2006) found reduced accomm in this cohort
What are Neuroleptics & Antipsychotics?
e.g. Phenothiazines
Used in schizophrenia
Reduce accomm by 40-100% (Thaler, 1979)
What are Bladder Spasmolytic Drugs?
e.g. Propiverine
Reduces accomm in children if high dose (Arfwidsson, 2007)
What are Antidysrhythmic Drugs?
e.g. Cibenzoline
Restore normal heart rhythm
Severely decreased accomm (Frucht et al, 1984)
What are Tricyclic Antidepressants?
e.g. Lorazepam
(Jung et al, 2012) - found reduced accommodation
(Speeg-Schatz et al, 2001) - found it affects convergence but not accomm
How do we manage:
Accomm Insufficiency,
Accomm Fatigue,
Accomm Inertia?
1) Correct refractive error
2) Treat any underlying cause
3) Orthoptic accommodative exercises
What did Horwood & Toor (2014) find out about accommodation and accommodation exercises?
Simple conv exercises are more effective at improving accomm than accomm exercises!
What other management can we use in Accommodative Deficiency?
Plus correction for near work (if no response to Tx aka treatment)
Wahlberg et al (2010) suggests +1DS instead of +2DS
Bifocal wear in Downs Syndrome
?Counselling/ referral to clinical psychologist
?Functional –> Dynamic Retinoscopy and +/- lenses
What management is there for accommodative paralysis?
- Treat cause
- Correct Rx
- Not able to exercise
- Prescribe reading addition (+ lens)
- Painted contact lens 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)
What is an example of Accommodative Excess?
Accommodative Spasm
What is Accommodative Spasm?
A condition where the ciliary muscle is contracted and cannot be relaxed, therefore accommodation is continuously exerted.
What are the Symptoms/Findings relating to Accommodative Spasm relating to:
- Blur
- Diplopia
- Pupils
- OM
- Dynamic RET
- Macropsia
- VA
- Blur
Yes - Diplopia
Variable ET, associated with excessive convergence - Pupils
Miosis - OM
Spasm on lateral gaze gives appearance of LR palsy - Dynamic RET
Accommodative lead - Macropsia
Possible - VA
Reduced due to pseudo-myopia
What is pseudo-myopia?
Spasm of the ciliary muscle prevents relaxation of accommodation so distance is blurred
What are the causes of Accommodative Spasm?
- Functional (underlying emotional response)
- Late onset myopia / sudden myopic increase
- Uncorrected hypermetropia
- Lack of relaxation after close work (mild)
- Manipulation of accomm to control ocular alignment (XT)
- Closed head trauma
- Rostral midbrain lesion
- MS
- Increased intracranial pressure (single report Kawasaki & Borruat 2005)
- Drugs
What are some drugs that can causse accommodative spasm and what did Pula et al (2013) find?
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
How do we investigate Accommodative 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
How do we manage 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
- Consider counselling / clinical psychologist – if needed to remove the stress factor
- Cycloplegics with reading correction
- BT to medial recti
- If functional then miotics/saline placebo
What else must we consider when we suspect Accommodative Spasm?
- Premature presbyopia
- Computer Vision Syndrome (CVS)
- Special needs children:
Cerebral palsy & Downs syndrome
What is the typical age of onset of presbyopia?
40 - 50 years of age
How do we treat Presbyopia?
+ve lenses
When might premature presbyopia occur?
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)
- Type 1 Diabetes (Sırakaya et al, 2020)
- HIV and AIDS (Mathebula & Makunyane, 2017)
What is Computer Vision Syndrome (CVS)?
Term used for complaints of computer users which include:
- Eyestrain
- Eye Fatigue
- Burning Sensations
- Dry Eyes
- Irritation
- Redness
- Blurred Vision
- Delay in Focusing
- Diplopia
Why does computer vision syndrome occur?
Excessive exposure to intense light, incl blue light, from screens may result in CVS
What did Cheng et al. (2014) find out about blue light filter glasses?
No sig effect on tear production and dry eyes but patients did report a sig improvement in comfort
(Cheng et al 2014)
What did Dabrowiecki et al. (2019) find out about blue light filter glasses?
Improvement in symptoms but not sig
(Dabrowiecki et al 2019)
What did The College of Optometrists (2018) say about blue light filter glasses?
‘The best scientific evidence currently available does not support the use of blue-blocking spectacle lenses’
What’s the management of CVS?
Rosenfield (2011)
- Treat any apparent accomm or conv anomaly
- Ensure refractive correction for distance of monitor (‘middle distance’)
- Blinking
- Take rest breaks
What is Accommodation like in 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)
What is Accommodation like in Down’s 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)
What is suggested in Down’s Syndrome with CI?
Bifocals suggested
- Improved accuracy in accommodation (Stewart et al, 2005)
- Literacy skills improve faster (Nandakumar et al, 2011)
How would we test accommodative abilities in Down’s Syndrome cases?
Use dynamic RET if unable to perform accomm tests (also useful in younger patients and functional cases)
