Preparation

The preparation for a dilation of the pupil at the ophthalmologist is usually very uncomplicated. For the examination, the patient should bring along a list of currently taken medications to avoid interactions with the eye drops used. Patients with elevated intraocular pressure or known glaucoma should not receive pupil dilating eye drops, as this can trigger a so-called glaucoma attack. Contact lenses must also be removed from the eye immediately before the procedure. These should also only be reinserted some time after the examination.

Procedure

Before dilating the pupil, the doctor will first ask for the most important exclusion criteria (drugs and diseases see above), if these are not already known. The actual procedure is very fast. The eye drops are dripped into one or both eyes. Then the patient can sit in the waiting room for another 15 minutes until the full effect is achieved. Only then can the actual examination, for which the previous pupil dilation is necessary, be performed.

Which eye drops are used?

Eye drops are used, which among other things can cause the pupil sphincter muscle (Musculus Sphincter Pupillae) to be temporarily paralyzed or the muscle that actively dilates the pupil (Musculus Dilatator Pupillae) to be activated. The active ingredient tropicamide is most frequently used for diagnostic purposes, as the effect is relatively quick to take effect and also fades away again. The following other eye drops are also suitable for diagnostic or therapeutic pupil dilation: neosynephrine, cyclopentolate, scopolamine, homatropin or atropine. However, the latter in particular is only used in exceptional cases, as the effect can last for several days.

Risks

The pupil dilation itself is quite low-risk thanks to modern active ingredients. In any case, however, it is important to inform the ophthalmologist about known pre-existing conditions. Especially the already mentioned glaucoma is the most important disease in this case, where pupil dilation must not take place.

After pupil dilation, side effects can also occur. However, in most cases these are completely harmless. These include burning eyes immediately after the drug has been applied to the eye.Side effects can rarely affect the whole body. In exceptional cases, for example, dry mouth or fast heartbeat (tachycardia) may occur.