Accommodative insufficiency
Accommodative insufficiency involves the inability of the eye to focus properly on an object, where the amplitude of accommodation is lesser compared to physiological limits for the person's age.
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AI is generally considered separate from presbyopia, though both represent difficulty engaging the near vision system.
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AI is generally considered separate from presbyopia , but mechanically both conditions represent a difficulty engaging the near vision system (accommodation) to see near objects clearly.
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AI is commonly present in people with convergence insufficiency.
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AI is commonly present in people with convergence insufficiency .
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AI is categorised into ill-sustained accommodation, paralysis of accommodation, and unequal accommodation.
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Accommodative insufficiency is further categorised into : Ill-sustained accommodation
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Ill-sustained accommodation has normal range initially but accommodative power decreases after excessive near work.
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range of accommodation will be normal, but after excessive near work accommodative power will decrease.
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Paralysis of accommodation may occur due to ciliary muscle paralysis, oculomotor nerve paralysis, or parasympatholytic drugs like atropine.
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It may occur due to ciliary muscle paralysis or oculomotor nerve paralysis.
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Systemic causes of ciliary muscle weakness include diabetes, pregnancy, stress, and malnutrition.
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Systemic causes of ciliary muscle weakness include diabetes , pregnancy , stress, malnutrition etc.
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Local causes include open angle glaucoma and iridocyclitis.
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Open angle glaucoma , Iridocyclitis etc. are known local causes.
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Near vision will be blurred.
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Near vision will be blurred
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Asthenopic symptoms like headache and eye strain may occur while reading.
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asthenopic symptoms like head ache and eye strain may occur while reading.
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Reduction of amplitude of accommodation by 2 dioptre or more is an important sign.
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Reduction of amplitude of accommodation by 2 dioptre or more is one of the important sign.
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Diagnosis involves identifying reduction of amplitude of accommodation by 2 dioptre or more.
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Reduction of amplitude of accommodation by 2 dioptre or more is one of the important sign.
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Unequal accommodation is diagnosed when amplitude of accommodation between the eyes differs by 0.5 dioptre or more.
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If there is amplitude of accommodation between the eyes differ 0.5 dioptre or more, it is considered as unequal.
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Underlying systemic or local causes should be treated.
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Underlying systemic or local causes should be treated.
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Weak convex lenses may be prescribed for near vision until accommodation improves to normal level.
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Weak convex lenses may be prescribed for near vision until accommodation improves to normal level.
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Accommodation exercises may be advised to improve accommodative power.
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Accommodation exercises may be advised to improve accommodative power.
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Organic diseases, head trauma, or functional amblyopia may be responsible for unequal accommodation.
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Organic diseases, head trauma or functional amblyopia may be responsible for unequal accommodation.
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Paralysis of accommodation may indicate ciliary muscle paralysis or oculomotor nerve paralysis.
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It may occur due to ciliary muscle paralysis or oculomotor nerve paralysis.
| Accommodative insufficiency | |
|---|---|
| Differential diagnosis | Convergence insufficiency. |
Accommodative insufficiency (AI) involves the inability of the eye to focus properly on an object. Accommodation is the adjustment of the curvature of the lens to focus on objects near and far.
In this condition, amplitude of accommodation of a person is lesser compared to physiological limits for his age.[1] AI is generally considered separate from presbyopia, but mechanically both conditions represent a difficulty engaging the near vision system (accommodation) to see near objects clearly. Presbyopia is physiological insufficiency of accommodation due to age related changes in lens (decreased elasticity and increased hardness) and ciliary muscle power.[1]
AI is commonly present in people with convergence insufficiency.[2]
Accommodative insufficiency is further categorised into :
Ill-sustained accommodation
Ill-sustained accommodation is a type of accommodative insufficiency in which, range of accommodation will be normal, but after excessive near work accommodative power will decrease.[3]
Paralysis of accommodation
In paralysis of accommodation, amplitude of accommodation is either markedly reduced or completely absent (cycloplegia).[4] It may occur due to ciliary muscle paralysis or oculomotor nerve paralysis.[1] Parasypatholytic drugs like atropine will also cause paralysis of accommodation.[3]
Unequal accommodation
If there is amplitude of accommodation between the eyes differ 0.5 dioptre or more, it is considered as unequal.[4] Organic diseases, head trauma or functional amblyopia may be responsible for unequal accommodation.[4]
Near vision will be blurred, and asthenopic symptoms like head ache and eye strain may occur while reading.[1] Reduction of amplitude of accommodation by 2 dioptre or more is one of the important sign.[4]
Premature sclerosis of lens or ciliary muscle weaknesses due to systemic or local cases may cause accommodative insufficiency.[1] Systemic causes of ciliary muscle weakness include diabetes, pregnancy, stress, malnutrition etc.[1] Open angle glaucoma, Iridocyclitis etc. are known local causes.[1]
Underlying systemic or local causes should be treated. Weak convex lenses may be prescribed for near vision until accommodation improves to normal level.[1] Accommodation exercises may be advised to improve accommodative power.
- 1 2 3 4 5 6 7 8 Khurana, AK (September 2008). "Asthenopia, anomalies of accommodation and convergence". Theory and practice of optics and refraction (2nd ed.). Elsevier. pp. 100–107. ISBN 978-81-312-1132-8.
- ↑ Synopsis of Clinical Ophthalmology (3 ed.). Elsevier. 2013. pp. 321–333.
- 1 2 Duke, Elder's (1969). "Anomalies of accommodation". The practice of refraction (8th ed.). London: Churchill. ISBN 0-7000-1410-1.
- 1 2 3 4 William J., Benjamin (2006). "Accommodation, the Pupil, and Presbyopia". Borish's clinical refraction (2nd ed.). St. Louis Mo.: Butterworth Heinemann/Elsevier. p. 112. ISBN 978-0-7506-7524-6.