Atropine eye drops are used in eye examinations and to treat certain eye infections. Read on for the effects, uses, side effects, and contraindications of these drops.
Atropine is an alkaloid that is extracted from the Atropa belladonna plant, and other plants that belong to the Solanaceae family. It is a secondary metabolite of these plants, and is an important anticholinergic drug used to treat many conditions. This means that this drug increases conduction through the atrioventricular node of the heart, and decreases the actions of the vagus nerve. In short, atropine tends to lower the parasympathetic action on the muscles and glands by reducing secretions in the body. This action is brought about because atropine is a competitive antagonist of acetylcholine receptors. Given below are details regarding the uses, effects, and side effects of these drops.
Effects and Uses
As atropine belongs to the group of anti-muscarinics, it blocks the receptors in the muscles of the eye when used in the form of eye drops. These are the receptors that are involved in controlling the size of the pupil and the shape of the lens of the eye. By blocking these receptors, atropine causes dilatation of the pupil, which is known as mydriasis. This then prevents ciliary muscle function, and so prevents the eye from performing the function of accommodation, that is, adjusting vision to near and distant objects. This paralysis of the ciliary muscles is known as cycloplegia. Thus, atropine eye drops are given to dilate the pupil and relax the lens. This is done so that eye examinations can be carried out without hindrance due to dilation and constriction of the iris of the eye. This is also often used to aid eye examinations in small children. The other use of atropine in the form of eye drops is also to relax muscles that are inflamed, and so, over contract in the eye, as is seen in uveitis, which is inflammation of the middle layer of the eye. Atropine in eye drops also help to relieve pain that is associated with iridocyclitis. It also helps in treating ciliary block (malignant) glaucoma.
Side Effects and Precautions
Although atropine causes a decrease in the amount of secretions in the body, it can lead to an increase in the pressure in the eye. Hence, this topical medication is contraindicated in patients that are suffering from, or have a predisposition to narrow angle glaucoma. There are certain precautions that one needs to take when he or she has been administered atropine eye drops. The eye loses out on the accommodation reflex. Furthermore, although the maximum effect of these eye drops is seen within an hour, the duration of action can go on for up to two weeks. Thus, a person may have blurry vision for up to two weeks. Due to this reason, the person should not drive a vehicle, operate any machinery, or perform any such activity that can be impaired due to blurry vision. Also, ensure that when instilling the eye drops, you do not touch the tip of the dropper, as contamination of this tip can lead to an eye infection.
There are many side effects of these eye drops, like blurred vision, slight irritation of the eye, an irregular heartbeat and even hallucinations. Sometimes, people also become photophobic and develop a sensitivity to light till the action of the drug lasts.
Although this drug is enlisted as an essential drug by WHO, and is considered to be relatively safe, in rare cases, a person may have an allergic reaction to these drops. There may be symptoms like swelling of the eyelid and severe discomfort. If this happens, the person should immediately report to the doctor so that the condition can be treated.