Cycloplegia refers to the paralysis of the ciliary muscle hindering accommodation. Due to the paralysis of the ciliary muscle, the curve of the eye cannot focus on the objects or images nearby. The ciliary muscle is a ring of the smooth muscle in the eye, typically in the middle layer, which controls viewing of objects at different distances. Moreover, the ciliary muscle also regulates the flow of specific aqueous humour into the Schlemm’s canal.
Cycloplegic drugs are used also used in cycloplegic refraction to paralyze the ciliary muscle to help examine the actual refractive issue of the eye. Moreover, cycloplegics are also used to treat uveitis. Essentially, all cycloplegics are also pupil dilating agents and used for dilating pupils, enabling better visualisation of the retina. Cycloplegics are very frequently used during eye examinations.
When the cycloplegic drugs are used to dilate pupils during eye exams, the pupil regains its function upon the cycloplegic drugs being metabolized or taken away. However, in some cases, the cycloplegic drugs can leave the pupil dilated for some days even after the examination is done. The cycloplegic medications used by the doctors generally wear off in some hours after their application; however, the patient is advised to wear strong protective sunglasses for comfort.
Functioning of cycloplegics
Typically, cycloplegics obstruct the functioning of acetylcholine. Acetylcholine is a stimulatory neurotransmitter that is associated with the autonomic nervous system. In the human eye, the acetylcholine is situated in the iris sphincter, and also in the ciliary body. These acetylcholine receptors function to cause a contraction of the iris, along with the ciliary body. With the use of cycloplegics, the doctor can control this activity by causing the ciliary body to become temporarily paralysed.
Overall, cycloplegics are very useful in providing relief from pain because of ocular inflammation. These drugs paralyze the ciliary muscle, thereby, helping the ciliary spasm relax. Moreover, the cycloplegics decrease the area of the posterior iris, which helps to prevent posterior synechiae formation.
Cycloplegics also help to minimise the intensity of cell and flare reaction, which typically occurs in the anterior chamber of the eye. Because of these various advantages of cycloplegics, they have been used by doctors to manage patients with corneal injury and an eye condition, known as uveitis.
Side effects of cycloplegic
Cycloplegics can cause some local and systematic issues after their usage. However, these issues are temporary a generally get better with time. Some of the common side effects of cycloplegic drugs include:
- Increased intraocular pressure
- Blurry vision
- A stinging feeling in the eye
- Dryness in the mouth and skin
- Rashes on the skin
- Abnormal reactions
- Behavioural issues
- Increased sensitivity to glare
- Reduced power to recognize hazards with low contrasts
That said, most cycloplegic agents do not any such issues. They are easy to apply, suppress much accommodation, wear of in-time, and do not have any side effects.
Overall, cycloplegic drugs are very useful in calming the ciliary muscle to enable the eye doctor to diagnose the eye condition properly or to carry out a treatment procedure. However, these drugs can have some side effects, which are temporary and fade away. But the usage of these drugs depends on the preference of the doctor and also on the general health of the condition.