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Tropicamide
Tropicamide, sold under the brand name Mydriacyl among others, is a medication used to dilate the pupil and help with examination of the eye. Specifically it is used to help examine the back of the eye. It is applied as eye drops. Effects occur within 40 minutes and last for up to a day. Common side effects include blurry vision, increased intraocular pressure, and sensitivity to light. Another rare but severe side effect is psychosis, particularly in children. It is unclear if use during pregnancy is safe for the fetus. Tropicamide is in the antimuscarinic part of the anticholinergic family of medications. It works by making the muscles within the eye unable to respond to nerve signals. Tropicamide was approved for medical use in the United States in 1960. It is on the World Health Organization's List of Essential Medicines. Medical use Tropicamide is an antimuscarinic drug that produces short acting mydriasis (dilation of the pupil) and cycloplegia when applied as ey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anticholinergic
Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous system by selectively blocking the binding of ACh to its receptor in nerve cells. The nerve fibers of the parasympathetic system are responsible for the involuntary movement of smooth muscles present in the gastrointestinal tract, urinary tract, lungs, sweat glands, and many other parts of the body. In broad terms, anticholinergics are divided into two categories in accordance with their specific targets in the central and peripheral nervous system and at the neuromuscular junction: antimuscarinic agents, and antinicotinic agents (ganglionic blockers, neuromuscular blockers). The term "anticholinergic" is typically used to refer to antimuscarinics which competitively inhibit the binding of ACh to muscarinic acetylcholine receptors; such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mydriatic
Mydriasis is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, trauma, or the use of certain types of drugs. Normally, as part of the pupillary light reflex, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A ''mydriatic'' pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which increases the pupillary aperture is referred to as a mydriasis. More generally, mydriasis also refers to the natural dilation of pupils, for instance in low light conditions or under sympathetic stimulation. Fixed, unilateral mydriasis could be a symptom of raised intracranial pressure. The opposite, constriction of the pupil, is referred to as miosis. Both mydriasis and miosis can be physiological. Anisocor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenylephrine
Phenylephrine is a medication primarily used as a decongestant, to dilate the pupil, to increase blood pressure, and to relieve hemorrhoids. In the United States, it was previously used orally as an over-the-counter decongestant to relieve nasal congestion due to sinusitis, but this use was discontinued in 2007. As of 2022, its use as a nasal decongestant in other applications still persists. Phenylephrine can be taken by mouth, as a nasal spray, given by injection into a vein or muscle, or applied to the skin. Common side effects when taken by mouth or injected include nausea, vomiting, headache, and anxiety. Use on hemorrhoids is generally well tolerated. Severe side effects may include a slow heart rate, intestinal ischemia, chest pain, kidney failure, and tissue death at the site of injection. It is unclear if use during pregnancy or breastfeeding is safe. Phenylephrine is a selective α1-adrenergic receptor agonist which results in the constriction of both arteries and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mydriasis
Mydriasis is the dilation of the pupil, usually having a non-physiological cause, or sometimes a physiological pupillary response. Non-physiological causes of mydriasis include disease, trauma, or the use of certain types of drugs. Normally, as part of the pupillary light reflex, the pupil dilates in the dark and constricts in the light to respectively improve vividity at night and to protect the retina from sunlight damage during the day. A ''mydriatic'' pupil will remain excessively large even in a bright environment. The excitation of the radial fibres of the iris which increases the pupillary aperture is referred to as a mydriasis. More generally, mydriasis also refers to the natural dilation of pupils, for instance in low light conditions or under sympathetic stimulation. Fixed, unilateral mydriasis could be a symptom of raised intracranial pressure. The opposite, constriction of the pupil, is referred to as miosis. Both mydriasis and miosis can be physiological. Aniso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cycloplegia
Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on nearby objects. This results in similar problems as those caused by presbyopia, in which the lens has lost elasticity and can also no longer focus on close-by objects. Cycloplegia with accompanying mydriasis (dilation of pupil) is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate. Belladonna alkaloids are used for testing the error of refraction and examination of eye. Management Cycloplegic drugs are generally muscarinic receptor blockers. These include atropine, cyclopentolate, homatropine, scopolamine and tropicamide. They are indicated for use in cycloplegic refraction (to paralyze the ciliary muscle in order to determine the true refractive error of the eye) and the treatment of uveitis. All cycloplegics are also mydria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pupil
The pupil is a black hole located in the center of the Iris (anatomy), iris of the Human eye, eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black because light rays entering the pupil are either absorbed by the biological tissue, tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil. The term "pupil" was coined by Gerard of Cremona. In humans, the pupil is round, but its shape varies between species; some Cat eyes, cats, reptiles, and foxes have vertical slit pupils, Goats#Anatomy and health, goats have horizontally oriented pupils, and some catfish have annular types. In optical terms, the anatomical pupil is the eye's aperture and the iris is the aperture stop. The image of the pupil as seen from outside the eye is the entrance pupil, which does not exactly correspond to the locatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscarinic Antagonist
A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. The muscarinic receptor is a protein involved in the transmission of signals through certain parts of the nervous system, and muscarinic receptor antagonists work to prevent this transmission from occurring. Notably, muscarinic antagonists reduce the activation of the parasympathetic nervous system. The normal function of the parasympathetic system is often summarised as "rest-and-digest", and includes slowing of the heart, an increased rate of digestion, narrowing of the airways, promotion of urination, and sexual arousal. Muscarinic antagonists counter this parasympathetic "rest-and-digest" response, and also work elsewhere in both the central and peripheral nervous systems. Drugs with muscarinic antagonist activity are widely used in medicine, in the treatment of low heart rate, overactive bladder, respiratory problems such as asthma and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antimuscarinic
A muscarinic receptor antagonist (MRA) is a type of anticholinergic agent that blocks the activity of the muscarinic acetylcholine receptor. The muscarinic receptor is a protein involved in the transmission of signals through certain parts of the nervous system, and muscarinic receptor antagonists work to prevent this transmission from occurring. Notably, muscarinic antagonists reduce the activation of the parasympathetic nervous system. The normal function of the parasympathetic system is often summarised as "rest-and-digest", and includes slowing of the heart, an increased rate of digestion, narrowing of the airways, promotion of urination, and sexual arousal. Muscarinic antagonists counter this parasympathetic "rest-and-digest" response, and also work elsewhere in both the central and peripheral nervous systems. Drugs with muscarinic antagonist activity are widely used in medicine, in the treatment of low heart rate, overactive bladder, respiratory problems such as asthma an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-Hydroxyamphetamine
4-Hydroxyamphetamine (4HA), also known as hydroxyamfetamine, hydroxyamphetamine, oxamphetamine, norpholedrine, ''para''-hydroxyamphetamine, and α-methyltyramine, is a drug that stimulates the sympathetic nervous system. It is used medically in eye drops to dilate the pupil (a process called mydriasis), so that the back of the eye can be examined. It is also a major metabolite of amphetamine and certain substituted amphetamines. Medical use 4-Hydroxyamphetamine is used in eye drops to dilate the pupil (a process called mydriasis) so that the back of the eye can be examined. This is a diagnostic test for Horner's syndrome. Patients with Horner's syndrome exhibit anisocoria brought about by lesions on the nerves that connect to the nasociliary branch of the ophthalmic nerve. Application of 4-hydroxyamphetamine to the eye can indicate whether the lesion is preganglionic or postganglionic based on the pupil's response. If the pupil dilates, the lesion is preganglionic. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilated Fundus Examination
Dilated fundus examination or dilated-pupil fundus examination (DFE) is a diagnostic procedure that employs the use of mydriatic eye drops (such as tropicamide) to dilate or enlarge the pupil in order to obtain a better view of the fundus of the eye. Once the pupil is dilated, examiners use ophthalmoscopy (funduscopy) to view the eye's interior, allowing assessment of the retina, optic nerve head, blood vessels, and other features. They also often use specialized equipment such as a fundus camera. DFE has been found to be a more effective method for evaluation of internal ocular health than non-dilated examination. It is frequently performed by ophthalmologists and optometrists as part of an eye examination An eye examination is a series of tests performed to assess vision and ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Eye examinations are primarily performed by an optometrist, .... References D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synechia (eye)
Ocular synechia is an eye condition where the iris adheres to either the cornea (i.e. ''anterior synechia'') or lens (i.e. ''posterior synechia''). Synechiae can be caused by ocular trauma, iritis or iridocyclitis and may lead to certain types of glaucoma. It is sometimes visible on careful examination but usually more easily through an ophthalmoscope or slit-lamp. Anterior synechia causes closed angle glaucoma, which means that the iris closes the drainage way of aqueous humour which in turn raises the intraocular pressure. Posterior synechia also cause glaucoma, but with a different mechanism. In posterior synechia, the iris adheres to the lens, blocking the flow of aqueous humor from the posterior chamber to the anterior chamber. This blocked drainage raises the intraocular pressure. Management Mydriatic or cycloplegic agents, such as topical homatropine, which is similar in action to atropine, are useful in breaking and preventing the formation of posterior synechia by kee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eye Examination
An eye examination is a series of tests performed to assess vision and ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Eye examinations are primarily performed by an optometrist, ophthalmologist, or an orthoptist. Health care professionals often recommend that all people should have periodic and thorough eye examinations as part of routine primary care, especially since many eye diseases are asymptomatic. Eye examinations may detect potentially treatable blinding eye diseases, ocular manifestations of systemic disease, or signs of tumours or other anomalies of the brain. A full eye examination consists of an external examination, followed by specific tests for visual acuity, pupil function, extraocular muscle motility, visual fields, intraocular pressure and ophthalmoscopy through a dilated pupil. A minimal eye examination consists of tests for visual acuity, pupil function, and extraocular muscle motilit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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