Amblyopia

Gillespie HA, Moke P, Beck R, Lester LA. Lessons learned in using web-based randomization in the community-based amblyopia treatment study. Controlled Clin Trials 2001 22 2S-80S. 

Much of the toxicological interest in cyanide relating to mammals has focused on its rapid lethal action. However, its most widely distributed toxicologic problems are due to its toxicity from dietary, industrial, and environmental factors (Way 1981, 1984 Gee 1987 Marrs and Ballantyne 1987 Eisler 1991). Chronic exposure to cyanide is correlated with specific human diseases Nigerian nutritional neuropathy, Leber s optical atrophy, retrobulbar neuritis, pernicious anemia, tobacco amblyopia, cretinism, and ataxic tropical neuropathy (Towill etal. 1978 Way 1981 Sprine etal. 1982 Beminger et al. 1989 Ukhun and Dibie 1989). The effects of chronic cyanide intoxication are confounded by various nutritional factors, such as dietary deficiencies of sulfur-containing amino acids, proteins, and water-soluble vitamins (Way 1981). 

The nervous system is the most sensitive target for cyanide toxicity, partly because of its high metabolic demands. High doses of cyanide can result in death via central nervous system effects, which can cause respiratory arrest. In humans, chronic low-level cyanide exposure through cassava consumption (and possibly through tobacco smoke inhalation) has been associated with tropical neuropathy, tobacco amblyopia, and Leber s hereditary optic atrophy. It has been suggested that defects in the metabolic conversion of cyanide to thiocyanate, as well as nutritional deficiencies of protein and vitamin B12 and other vitamins and minerals may play a role in the development of these disorders (Wilson 1965). 

Persons with a metabolic disturbance in the conversion of cyanide to thiocyanate may be at greater risk. A defect in the rhodanese system and vitamin B12 deficiency have been associated with tobacco amblyopia and Leber s hereditary optic atrophy in persons exposed to cyanide in tobacco smoke (Wilson 1983). 

Pettigrew AR, Fell GS. 1972. Simplified colorimetric determination of thiocyanate in biological fluid and its application of investigation of toxic amblyopias. Clin Chem 18 996-1000. 

An illustration of the variable responses to nicotine concerns aphids. In an experiment, 2 per cent of an insect population died or became moribund when exposed to 0.0001 M nicotine solution, 48 per cent were affected when the concentration was 0.0025 M, and 98.5 per cent when the concentration was 0.012 M. The concentrations of nicotine required to affect all the insects alike varied more than 120-fold.21 The pharmacology of nicotine as studied in mammals is notably complex and unpredictable, partly because many sites of action are involved. Its effect on different human individuals is also diverse, but it has not been adequately investigated, particularly in view of the fairly well established fact that amblyopia and Buerger s disease occur in relatively rare cases directly because of its use.22... 

Lund A Toxic amblyopia after inhalation of methyl acetate. J Ind Hyg Toxicol 28 35 (abstr), 1946. 106 408-422, 1944... 

M/sce/Zaneoas. Atrial fibrillation and other cardiac arrhythmias, cystoid macular edema, decreased glucose tolerance, hypotension, orthostasis, toxic amblyopia, transient headache. 

Special senses - Blurred vision photophobia amblyopia swollen, dry, or irritated eyes conjunctivitis iritis reversible loss of color vision hearing disturbances or loss ear pain change in taste (metallic or bitter) diplopia tinnitus. 

Special senses Tinnitus diplopia taste perversion amblyopia deafness visual field defect eye pain conjunctivitis photophobia hyperacusis mydriasis parosmia ear pain taste loss. 

Adverse reactions occurring in at least 3% of patients include somnolence, weight gain, hostility, emotional lability, nausea/vomiting, bronchitis, viral infections, fever, dizziness, ataxia, fatigue, nystagmus, rhinitis, diplopia, amblyopia, tremor, asthenia, headache, peripheral edema, diarrhea, constipation, dry mouth. 

Adverse reactions that occurred in 3% or more of patients include the following abnormal gait, abdominal pain, accidental injury, amblyopia, asthenia, ataxia, confusion, cough increased, depression, diarrhea, difficulty with concentration/attention, difficulty with memory, dizziness, ecchymosis, emotional lability, flu syndrome, hostility, infection, insomnia, myalgia, nausea, nervousness, paresthesia, pain (unspecified), pharyngitis, rash, somnolence, speech disorder, tremor, urinary tract infection, vomiting. 

The most frequent adverse experiences associated with pilocarpine were a consequence of the expected pharmacologic effects. Adverse reactions occurring in at least 3% of patients include the following Sweating, nausea, rhinitis, chills, flushing, urinary frequency, dizziness, asthenia, headache, dyspepsia, lacrimation, diarrhea, edema, abdominal pain, amblyopia, vomiting, pharyngitis, and hypertension. 

Isosorbide Dinitrate Hydralazine (BiDil) [Antianginal, Antihypertensive/Vasodilator, Nitrate] Uses HF in African Amer-icans improve survival functional status, prolong time between hospitalizations Action Relaxes vascular smooth muscle peripheral vasodilator Dose Initially 1 tab tid PO (if not tol ated reduce to 1/2 tab tid), titrate >3-5 d as tolerated Max 2 tabs tid Caution [C, /-] recent MI, syncope, hypovolemia, hypotension, hep impair Contra For children, concomitant use w/ PDE5 inhibitors (sildenafil) Disp Tabs SE HA, dizziness, orthostatic hypotension, sinusitis, GI distress, tach, paresthesia, amblyopia Interactions t Risk of severe hypotension W/ antihypertensives, ASA, CCBs, MAOIs, phenothiazides, sildenafil, tadalafil, vardenafil, EtOH X pressor response Wf i -1- effects W7 NSAIDs EMS Use ASA, antihypertensives and CCBs w/ caution, may t hypotension concurrent Viagra-type drug use can lead to profound hypotension concurrent EtOH use can t effects OD May cause N/V, profound hypotension, skin flushing, HA from ICP, bradycardia, confusion, and circulatory collapse activated charcoal may be effective, epi use is contraindicated... 

Like many volatile halocarbons and other hydrocarbons, inhalation exposure to carbon tetrachloride leads to rapid depression of the central nervous system. Because of its narcotic properties, carbon tetrachloride was used briefly as an anesthetic in humans, but its use was discontinued because it was less efficacious and more toxic than other anesthetics available (Hardin 1954 Stevens and Forster 1953). Depending on exposure levels, common signs of central nervous system effects include headache, giddiness, weakness, lethargy, and stupor (Cohen 1957 Stevens and Forster 1953 Stewart and Witts 1944). Effects on vision (restricted peripheral vision, amblyopia) have been observed in some cases (e.g., Johnstone 1948 Smyth et al. 1936 Wrtschafter 1933), but not in others (e.g., Stewart and Wtts 1944). In several fatal cases, microscopic examination of brain tissue taken at autopsy revealed focal areas of fatty degeneration and necrosis, usually associated with congestion of cerebral blood vessels (Ashe and Sailer 1942 Cohen 1957 Stevens and Forster 1953). 

Wirtschafter ZT. 1933. Toxic amblyopia and accompanying physiological disturbances in carbon tetrachloride intoxication. Am J Public Health 22 1035-1038. 

Adverse effects that are not unequivocally related to inhibition of prostaglandin synthesis include hepatic effects (hepatitis, hepatic necrosis, cholestatic jaundice, increased serum aminotransferases), dermal effects (photosensitivities, Stevens-Johnson syndrome, toxic epidermal necrolysis, onycholysis), central nervous system (CNS) effects (headaches, dizziness, tinnitus, deafness, drowsiness, confusion, nervousness, increased sweating, aseptic meningitis), ocular effects (toxic amblyopia, retinal disturbances), and certain renal effects (acute interstitial nephritis, acute papillary necrosis). 

Contraindications Compensatory hypertension (atrioventricular AV shunt or coarctation of aorta), congenital (Leber s) optic atrophy, inadequate cerebral circulation, moribund patients, tobacco amblyopia... 

Nervousness, amblyopia, pharyngitis, rhinitis, vomiting, urinary frequency Serious Reactions... 

Side effects are similar to those of other stimulants. Additionally, some patients may experience confusion, ataxia, hyperglycemia, gingival ulcers, urinary retention, paresthesias, neck and joint discomfort, amblyopia, pharyngitis, or dyspnea. 

A study in the USA has produced some evidence that in people with amblyopia, those who were exposed to diethylstilbestrol before birth may be more likely to develop myopia (43). 

Arnold RW, Gionet E, Hickel J, et al. Duration and effect of single-dose atropine paralysis of accommodation in penalization treatment of functional amblyopia. Binocul Vis Strabismus Q. 2004 19 81-86. 

Amblyopia, decreased visual acuity and color perception. 

Commonly reported adverse effects are dry mouth, weakness, somnolence, nausea, dizziness, constipation, light-headedness, amblyopia, and blurred vision (1,2). 

Strabismus or amblyopia Contact lens wear Current ocular medications Eye surgery... 

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