Cycloplegia- A complete understanding
Cycloplegia is a phenomenon that occurs in the eyes when we treat them with cycloplegics. It is the paralysis of ciliary muscles of the eyes. The pupil also dilates in this phenomenon in most cases.
How ciliary muscles work?
In cycloplegia, there occurs the paralysis of ciliary muscles. Well lets understand the working of ciliary muscles and their importance as given below. Why do we not want to have accommodation phenomenon? Is there any significance of cycloplegia?
Consider you are using using your smart phone and watching your favorite show on it. The use of device causes stress on the eye muscles while watching near objects e.g. smart phone in this case. You are sitting on the roof of your place. You hear an airplane sound and you see the sky to see the plane. Do you know what happened to your lenses? Well you just shifted your eyes from watching a near object to focusing a far and undoubtedly a very far object. The lens power changes with respect to your distance from the object. When you focus on your smart phone then your lens changes its shape in such a way that its power increases. The ciliary muscles are attached to your lenses that help your lenses to change their shape to focus near and far objects. These muscles are also called eye focusing muscles.
Accommodation
Remember that when you see near objects these muscles contract to help your lens focus on near objects. When you are seeing a distant objects these muscles relax and the thickness of the lens decreases. The phenomenon of seeing near objects is known as accommodation.
Other causes for the paralysis of accommodation include
- Third nerve paralysis
- Paralytic internal ophthalmoplegia
Importance of cycloplegia
Cycloplegia drops also help in refraction. These drops are given to children below 16 years of age to find their refractive errors correctly.1 percent cyclopentolate is given to the patients. Cycloplegic refraction occurs in patients. The children below 16 years have greater capacity of accommodation. This helps them to cover their refractive error. When cycloplegia occurs in their eyes, the paralysis of their ciliary muscles lead to inability to accommodate.
How much dose should be administered to get cycloplegia?
Cyclopentolate is given as one drop for 3 times for every 15 minutes for each eye. Other drugs have different dosage.
When to perform cycloplegia
- If the patient (remember that the patients must be maximum of 16 years of age) comes with hypermetropia, then it is important to use cycloplegics before performing refraction.
- If the patients come to you with only asthenopic symptoms, then must perform refraction with cycloplegia to find out if the patient has latent refractive error or not.
- Asthenopic symptoms include blurring of vision, headache, eyes pain and fatigue in eyes muscles.
- If the children are non-cooperative, then perform cycloplegia.
Contraindication for cycloplegia
We don’t perform cycloplegic refraction if the patient is allergic to cyclopentolate hydrochloride and if he has increased IOP (intra-ocular pressure). It is also prohibited in the patients of narrow angle glaucoma.
Side effects
Whenever we administer eyedrops into the eye, then get absorb in the systemic circulation and can cause systemic side effects.
Ocular side effects
Blurring of vision
Photophobia
Burning sensation
Systemic side effects
Restlessness
Fever
Urinary retention
Confusion
Constipation
Drugs that cause cycloplegia
- Cyclopentolate
- Atropine
- Homatropine
- Tropicamide
Uses of cycloplegia drugs
They are used to find out actual refractive error in young adults
These drugs also used to relieve pain caused by the regular contraction of ciliary muscles in ocular diseases like Iridocyclitis, corneal ulcers and keratitis. They are also used to prevent synechiae formation after cataract surgeries in eyes.
After cataract cycloplegics are prescribed for at least two weeks. That is why they wear goggles to protect their mydriatics eyes form the light rays.
As an optometrist you can perform eye refraction of children using cycloplegia. It is due to children have greater ability to accommodate than adults. This ability hinders the optometrists to find exact correction of eyes. Thus there is a need to get rid of accommodation to get exact error of myopia or hyperopia while performing Retinoscopy.
Founder of EyesMatterMost- an optometry student who loves talking about eyes. I tend to cover topics related to optometry, ophthalmology, eye health, eyecare, eye cosmetics and everything in between. This website is a medium to educate my readers everything related to eyes.