If your eyes will be dilated for an exam or procedure, bring sunglasses with you. They will help with the glare and light sensitivity when you leave your appointment. The effects of dilating eye drops last a few to several hours. Your eye doctor cannot tell you how blurry your vision will be and for how long.
That depends on the type of dilating eye drop used and how your eyes react. It may not be safe to drive yourself after having your eyes dilated. You should make arrangements to have someone drive you after your appointment. If you have any questions before or after a dilated eye exam or procedure, be sure to speak with your eye doctor.
Elderly people are especially sensitive to the effects of tropicamide. This may increase the chance of side effects during treatment. There are no adequate studies in women for determining infant risk when using this medication during breastfeeding.
Weigh the potential benefits against the potential risks before taking this medication while breastfeeding. Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur.
In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below.
The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive. Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines. Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur.
Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco. The presence of other medical problems may affect the use of this medicine.
For the purposes of this article, only the mydriatic effect of the drug will be discussed. Cycloplegia will be reviewed later in the year. Provided it is in the course of their professional practice and in an emergency, registered optometrists may sell or supply POMs, which are not for parenteral administration, and that contain the following substances with regard to mydriasis:.
All POMs and P medicines to which the Medicines Act exemptions apply may be sold to a registered optometrist by way of wholesale dealing. Also, a registered optometrist may obtain the following medicinal products by way of wholesale dealing:.
POM medicines for administration as opposed to sale or supply — this relates to topical anaesthetic which will be discussed in a future article.
A formulary of drugs available to optometrists may be downloaded from the College of Optometrists website. Administration of a drug to the eye aims to produce an adequate amount of drug at the site of action and to maintain it there for as long as necessary while minimising systemic side effects.
The amount of drug administered is determined by its absorption from the site of administration, its redistribution and the elimination of the active form, either by excretion or metabolism. In optometric drug use, the most important of these is absorption.
To cross effectively, a drug must be both lipid and water-soluble. Most drugs used in optometry are either weak bases or weak acids; therefore they can exist in both an ionised and a non-ionised form. The degree of ionisation is determined by the pH of the medium in which the drug is located and the acid-base dissociation usually described as the pKA of the drug. The pH, but not the pKa, may be changed, within limits, to influence ionisation. Ionisation is important because the non-ionised form tends to be lipid soluble, whereas the ionised form is likely to be water-soluble.
For effective crossing of the cornea both forms of the drug are needed. The nervous system consists of the central nervous system and peripheral nervous system. The peripheral nervous system can be further categorised to compromise of the autonomic nervous system ANS and somatic nervous system SoNS. See Figure 1 for a schematic overview of the structures involved in each. Mydriatics produce their effects directly or indirectly on the ANS.
A typical pathway comprises two neurones with a junction, the ganglion, between them. Transmission across the ganglion and across the junction between the nerve and the cell it innervates the neuroeffector junction is by chemical means. The chemical involved is called a neurotransmitter. The ANS consists of two branches, the parasympathetic nervous system and the sympathetic nervous system.
The parasympathetic system is characterised by long pre-ganglionic and short post-ganglionic nerves, whereas the sympathetic system is characterised by short pre-ganglionic and long post-ganglionic nerves. With regard to use of mydriatics, the most significant difference is the nature of the neurotransmitter at the neuroeffector junction.
At parasympathetic junctions this is acetylcholine and at the sympathetic it is noradrenaline. These neurotransmitters produce their effects by binding to and interacting with receptors located at the membrane of the innervated cell Figure 2. Figure 2: Neurotransmitters in the nervous system. Drugs with similar structures which are also able to bind show affinity and interact to produce the same response efficacy are termed agonists.
Those with affinity but no efficacy are termed antagonists. These will occupy the receptor and prevent access of the normal neurotransmitter, thus they will reduce or abolish the normal response to nerve stimulation. The parasympathetic nerves supply the iris sphincter, the ciliary muscle and the lacrimal gland. Stimulation causes contraction of the iris and ciliary muscle resulting in miosis closure of the pupil and spasm of accommodation along with increased activity in the lacrimal gland.
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