Pseudomyopia refers to an intermittent and temporary shift in refraction

Refraction

Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...

 of the eye towards myopia

Myopia

Myopia , "shortsightedness" ) is a refractive defect of the eye in which collimated light produces image focus in front of the retina under conditions of accommodation. In simpler terms, myopia is a condition of the eye where the light that comes in does not directly focus on the retina but in...

, in which the focusing of light in front of the retina is due to a transient spasm of the ciliary muscle

Ciliary muscle

The ciliary muscle is a ring of striated smooth muscle in the eye's middle layer that controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humour into Schlemm's canal. It changes the shape of the lens within the eye not the size of the pupil which is...

 causing an increase in the refractive power of the eye. It may be either organic, through stimulation of the parasympathetic nervous system

Parasympathetic nervous system

The parasympathetic nervous system is one of the two main divisions of the autonomic nervous system . The ANS is responsible for regulation of internal organs and glands, which occurs unconsciously...

, or functional in origin, through eye strain or fatigue of ocular systems. It is common in young adults who have active accommodation

Accommodation (eye)

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image on an object as its distance changes....

, and classically occurs after a change in visual requirements, such as students preparing for an exam, or a change in occupation.

The major symptom is intermittent blurring of distance vision particularly noticeable after prolonged periods of near work, and symptoms of asthenopia

Asthenopia

Asthenopia or eye strain is an ophthalmological condition that manifests itself through nonspecific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache and occasional double vision...

. The vision may clear temporarily using concave (minus) lenses. The diagnosis is done by cycloplegic refraction

Cycloplegia

Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation.-Anatomy:The iris is the heavily pigmented colored part of the eye. It has a contractile diaphragm in front of the lens with a central opening called the pupil...

 using a strong cycloplegic like atropine

Atropine

Atropine is a naturally occurring tropane alkaloid extracted from deadly nightshade , Jimson weed , mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects...

 or homatropine

Homatropine

Homatropine is an anticholinergic medication that inhibits muscarinic acetylcholine receptors and thus the parasympathetic nervous system...

 eye drops. Accommodative amplitude and facility may be reduced as a result of the ciliary muscle spasm.

Treatment is dependent on the underlying aetiology. Organic causes may include systemic or ocular medications, brain stem injury, or active ocular inflammation such as uveitis

Uveitis

Uveitis specifically refers to inflammation of the middle layer of the eye, termed the "uvea" but in common usage may refer to any inflammatory process involving the interior of the eye....

. Functional pseudomyopia is managed though modification of working conditions, an updated refraction, or through appropriate ocular exercises.