الفهرس | Only 14 pages are availabe for public view |
Abstract Spasm of accommodation of the eye is one of accommodative dysfunction. It is a condition resulting from over stimulation of parasympathetic nervous system. Sustained accommodative effort and long near work causes accommodative spasm and Asthenopia. In spasm of accommodation the Tone of ciliary muscle is increased and a constant accommodative effort is expended by the parasympathetic nervous system. Pseudomyopia produced. Symptoms Blurred vision depending on patient’s refractive status. Macropsia. Asthenopia during close work. Pain (brows/headache). Poor concentration . Miosis. Convergence anomalies (excess or insufficiency). Investigation Cycloplegic refraction used to determine true refraction Aetiology Spasm can be further categorised into: (a) Functional spasm (b) Organic spasm Functional spasm A response to over fatigue and ”eye strain”. Precipitated by 3 factors: 1-Bad visual hygiene e.g., poor lighting, glare unaccustomed work. 2-Optical or ocular motor difficulties e.g., anisometropia, early presbyopia, convergence anomalies. 3-psychological factors Treatment of functional spasm Eliminate exciting cause. Consider occupation, general health, mental state. Correct refractive error and/or ocular motor anomaly. Organic spasm Irritation of parasympathetic system. Aetiology *Ciliary spasm - drug induced e.g., physostigmine, pilocarpine, morphine, digitalis. - lesions of brain stem . *Inflammation e.g., anterior uveitis. *Trigeminal neuralgia *Others e.g., diphtheria, tooth extraction. Treatment of organic spasm manage the cause. Anomalies of accommodation are very common. Management of these anomalies is an integral part of optometric practice. Evaluation of a case of spasm of accommodation needs good history and examination of both neurological and visual system. Management of case of spasm of accommodation needs both treatment of underlying cause as in head trauma and error of refraction. The role of cycloplegics, patient education and vision therapy is very essential. |