Cycloplegic refraction.pptx

Cycloplegic refraction

1. Cycloplegic refraction Madiha nazly Optometrist/ coavs

2. Cycloplegic refraction is performed to ascertain the cause of a refractive error without any adjustment of the focus by the person being tested . For example, when refraction is performed without cycloplegic eye drops, there could a conscious or unconscious influence on the readings by the patient. Sometimes the patient may be subconsciously over-focusing. This may make someone appear more nearsighted or less farsighted than they actually are . Cycloplegic drops paralyze the focusing muscles of the eye and prevent the accommodating reflex by which focus is automatically adjusted. Doing so ensures a more accurate diagnosis and prescription

3. Sometimes when people come in for an eye examination, things are not always what they seem. An example of this that occurs with fluctuating prescriptions. Let's say that a person comes for refraction. The examination goes smoothly and a new prescription for eyeglasses is made. A few days later, the person comes back in claiming that the glasses helped a little but that the eyes are extremely tired and the glasses "did not seem right." Upon hearing the news, you recheck the prescription by performing regular refraction. However, this time around, the patient is able to see 6/6 through a variety of lens powers. In instances like this, you realize that the patient was indeed farsighted but had a large amplitude of accommodation. This means that the patient was able to compensate for the farsightedness by adjusting the accommodation (focus) of the eye

4. While the drops can cause short-term blurriness and light sensitivity, it allows you to measure the entire amount of farsightedness. In this way true refractive error can be measured and prescription adjusted accordingly.

5. Types of cycloplegic agents Atropine eye drops = -1.0 ds Homatropine eye drops = -0.50ds Cyclopentolate = 00.75ds

6. Indications Cycloplegic drops are not needed by everyone searching for a new pair of eyeglasses. They are used for a very specific purpose in those with a large amplitude of accommodation. There are four groups of people that cycloplegic refraction may benefit with.

7. Children​ A cycloplegic refraction is often performed on children. Children have the ability to accommodate a great deal . Also, children tend to focus at a close range and are unable to control their focusing when they are supposed to be looking at a far distance during an examination.

8. Hyperopia . Uncorrected hypermetropia can result in accommodative esotropia , strabismic amblyopia and isometropic amblyopia.   Children with >3.50ds of hypermetropia have a 13 times greater risk of developing strabismus or amblyopia. Esotropia .  New onset of/ previously well-controlled accommodative esotrope is an indication for cycloplegic refraction. This allows us to determine whether the eye turn has an accommodative component. Anisometropia  is a very powerful amblyogenic risk factor. Over +1.00ds difference between two eyes can put a child at risk of developing anisometropic amblopia . It is not surprising to find a much larger difference in refractive error between the two eyes after cyclodilation .  If you don’t prescribe the full anisometropic difference between the two eyes, the amblyopia/reduced acuity may not fully resolve despite occlusion therapy/patching. Treatment of anisometropia should consist of symmetric reduction of hypermetropia of up to 2.00 D.

9. Accommodative Spasm . In older children and young adults, cycloplegic refraction can confirm the diagnosis of accommodative spasm, which is a constant or intermittent, involuntary increase in ciliary contraction. Patients with low hyperopia may present as myopic during examination; this so-called pseudomyopia can be identified by cycloplegic evaluation. Asthenopia with near work . This applies for children and young adults. A study of young adults18-21 years old showed that they possessed +1 to +2 D of latent hypermetropia . Should they complain of headaches with near work and asthenopia , cycloplegic refraction is indicated.

10. Pre-Presbyopia Presbyopia is a condition that affects all of us around the age of 40 to 45. It is when we begin to lose our ability to focus on near objects. This is why people over 40 are often using reading glasses or wearing a bifocal. However, in some people, symptoms may develop much earlier (a condition referred to as pre-presbyopia). They will be unable to focus quickly from near to far distance or be unable to focus properly at night. The best way to isolate the problem is for the doctor to perform cycloplegic refraction

11. LASIK Candidates People who decide to have  l aser vision correction (LASIK ) or other refractive surgery must undergo cycloplegic refraction . This is performed to ensure that their accommodation does not interfere with the results. The surgeon needs to know exactly how much of the person's vision problem to correct with the laser

12. Side Effects Cycloplegic eye drops do tend to sting for a few seconds when first applied to the eye. Depending on the type of drop used, they can cause blurriness and light sensitivity for several hours. Some people may even continue to have blurriness the next day. Protective disposable sunglasses are typically provided to prevent squinting and discomfort as well as to protect the eye from sun damage. Cycloplegic eye drops can also cause an acute angle-closure glaucoma attack in people with very narrow angles. It should be checked to make sure you are not at risk for glaucoma before instilling the eye drops.