Pseudomyopia refers to an intermittent and temporary shift in refraction of the eye towards myopia, in which the focusing of light in front of the retina is due to a transient spasm of the ciliary muscle causing an increase in the refractive power of the eye. It may be either organic, through stimulation of the parasympathetic nervous system, or functional in origin, through eye strain or fatigue of ocular systems. It is common in young adults who have active accommodation, and classically occurs after a change in visual requirements, such as students preparing for an exam, or a change in occupation.
Pseudomyopia (false nearsightedness) is also termed spasm of accommodation, accommodative excess, spurious myopia and because of strong eyepain some researchers also use the term painful accommodation and is crucial for understanding prevention of nearsightedness (myopia).
The major symptom is intermittent blurring of distance vision particularly noticeable after prolonged periods of near work, and symptoms of asthenopia. The vision may clear temporarily using concave (minus) lenses. The diagnosis is done by cycloplegic refraction using a strong cycloplegic like atropine or homatropine 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. Functional pseudomyopia is managed though modification of working conditions, an updated refraction, typically involving a reduction of a myopic prescription to some lower myopic prescription, or through appropriate ocular exercises.
Pseudomyopia is easily cured if early recognized and treated, otherwise the relaxation of spasm of accommodation could become much more difficult.
If refraction is not properly done, there is a danger that pseudomyopia could be overlooked and wrongful diagnosis myopia or much higher myopia than actually exists could be established. In these cases prescription of minus glasses could induce more spasm and make the condition worse.
Over-correction can produce asthenopia i.e. eyestrain, pain in and around the eyes, headaches, migraines and even many remote symptoms by interference of the balance in autonomous nervous system which controls accommodation (focusing power of the eye). Pain may radiate to upper neck (occipital) and down the neck to the shoulders.
Chentsova O, Shatalov O (2002). "Comparative analysis of the efficacy of some methods of conservative treatment of accommodation spasms and myopia in children". Vestn Oftalmol 118 (6): 10–2. PMID 12506647.