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. 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.AI is commonly present in people with convergence insufficiency. Categories
Accommodative insufficiency is further categorised into different categories. 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. Paralysis of accommodation
In paralysis of accommodation, amplitude of accommodation is either markedly reduced or completely absent (cycloplegia). It may occur due to ciliary muscle paralysis or oculomotor nerve paralysis. Parasypatholytic drugs like atropine will also cause paralysis of accommodation. Unequal accommodation
If there is amplitude of accommodation between the eyes differ 0.5 dioptre or more, it is considered as unequal. Organic diseases, head trauma or functional amblyopia may be responsible for unequal accommodation. Causes
Premature sclerosis of lens or ciliary muscle weaknesses due to systemic or local cases may cause accommodative insufficiency. Systemic causes of ciliary muscle weakness include diabetes, pregnancy, stress, malnutrition etc. Open angle glaucoma, Iridocyclitis etc. are known local causes.
Bodies found at the scene of an accidental death often show evidence of other paraphilic activities, such as fetishistic cross-dressing and masochism. In cases involving teenagers at home, families may disturb the scene by "sanitizing" it, removing evidence of paraphilic activity. This can have the consequence of making the death appear to be a deliberate suicide, rather than an accident.The great majority of known erotic asphyxial deaths are male; among all known cases in Ontario and Alberta from 1974 to 1987, only 1 out of 117 cases was female. Some individual cases of women with erotic asphyxia have been reported. The main age of accidental death is mid-20s, but deaths have been reported in adolescents and in men in their 70s.Autoerotic asphyxiation has at times been incorrectly diagnosed as murder and especially so when a partner is present.Lawyers and insurance companies have brought cases to the attention of clinicians because some life insurance claims are payable in the event of accidental death, but not suicide. In fiction
The sensational nature of erotic asphyxiation often makes it the subject of urban legends. It has also been mentioned specifically in a number of works of fiction. In the Marquis de Sades famous novel Justine, or The Misfortunes of the Virtue, Justine is subjected to this by one of her captors. She survives the encounter. In the Guts short story in Chuck Palahniuks novel Haunted, one the characters discusses parents who discover the accidental deaths of their sons to autoerotic asphyxiation.