Spasm of accommodation

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A spasm of accommodation (also known as a ciliary spasm, an accommodation, or accommodative spasm) is a condition in which the ciliary muscle of the eye remains in a constant state of contraction. Normal accommodation allows the eye to "accommodate" for near-vision. However, in a state of perpetual contraction, the ciliary muscle cannot relax when viewing distant objects. This causes vision to blur when attempting to view objects from a distance. This may cause pseudomyopia or latent hyperopia.

Contents

Although antimuscarinic drops (homoatropine 5%) can be applied topically to relax the muscle, this leaves the individual without any accommodation and, depending on refractive error, unable to see well at near distances. Also, excessive pupil dilation may occur as an unwanted side effect. This dilation may pose a problem since a larger pupil is less efficient at focusing light (see pupil, aperture, and optical aberration for more.)

Patients who have accommodative spasm may benefit from being given glasses or contacts that account for the problem or by using vision therapy techniques to regain control of the accommodative system.

Possible clinical findings include:

Treatments

Cycloplegic Eye Drops (Dilation)

Spasm of accommodation is frequently resistant to treatment. However, some patients do find relief through the use of daily eye dilation with cycloplegic drops. One side effect of cycloplegic drops is that they often have BAK as a preservative ingredient, which, with daily use, can erode the tear shield:

At each administration of an eye drop containing benzalkonium chloride, its detergent effect disrupts the lipid layer of the tear film. This cannot be regenerated and can no longer protect the aqueous layer of the tear film, which evaporates easily. In these circumstances, the cornea is exposed and eye dryness occurs. In addition, benzalkonium chloride has a cellular toxicity on caliciform cells, entailing a reduction in the amount of mucin, an additional reason for disrupting the tear film. [1]

In fact, none of the cycloplegic drops used to treat Spasm of Accommodation in the United States are available without BAK. This unfortunately makes treatment much more difficult as the side effect of dry eyes and corneal damage can occur. France, Australia, Canada, and the United Kingdom do have limited availability of BAK-free eye drops available in unidose, and they must be imported to the United States with a physician's letter to the FDA [2] enclosed with the imported prescription.

Due to the high potential of tear shield damage with long-term use and the associated dry eye condition caused by cycloplegic eye drops with BAK (preservative), many physicians do not recommend cycloplegic eye drops. In difficult cases, "cycloplegic agents are highly favored to break spasm quickly and may be more economical compared to other conventional therapies" [3]

Cyclopentolate, Atropine, Tropicamide, and Homatropine are the typical cycloplegic eye drops used once daily to treat spasm of accommodation by relaxing the ciliary muscle. One side effect is blurred vision since these induce dilation.

Vision Training

Vision therapy administered by a trained optometrist has shown a success rate of over 70%. [4]

Surgery

Multifocal intraocular lens implantation is a new possible treatment involving clear lens extraction and multifocal intraocular lens implantation [5] but it may not be appropriate for patients who have had resistant spasm of accommodation for a long period of time.

Research

Experimental Nitroglycerin and Nitric Oxide

Animal studies [6] [7] have found nitroglycerin, a vasodilator used to treat angina, relaxes the ciliary muscle and may hold hope for those suffering from spasm of accommodation. Nitroglycerin is currently being investigated as a treatment for glaucoma, and has shown to decrease intraocular pressure and relax the ciliary muscle. According to Investigative Ophthalmology & Visual Science Journal. "In a nonhuman primate study, topical administration of nitroglycerin at a dose of 0.1% significantly decreased IOP in normotensive animals after 90 minutes". [7] Further, according to Wiederholt, Sturm, and Lepple-Wienhues, [8] "The data indicate (indicates[ sic ]) that an increase of intracellular cGMP by application of cGMP and organic nitrate or non-nitrate vasodilators induces relaxation of the bovine trabecular meshwork and ciliary muscle".

Experimental Perilla frutescens

Since spasm of accommodation is a result of contraction of the ciliary muscle, the goal would be to relax the ciliary muscle. New studies conducted on rats using perilla frutescens aqueous extract have shown to relax the ciliary muscle. Since there are no known drugs to treat this eye condition, perilla frutescens in an aqueous extract form may result in the relaxation of the ciliary muscle in humans as well. Perilla frutescens is currently used in traditional medicine in Korea, Japan, and China and a clinical study "showed that PFA (perilla frutescens extract) attenuates eye fatigue by improving visual accommodation" [9]

Prognosis

For routine cases of spasm of accommodation, the American Optometric Association says the prognosis is fair and on average, the number of visits a patient needs will be 1-2 for evaluation and 10 follow up visits. [10] Additionally, the AOA recommends the following management plan for spasm of accommodation: "Begin with plus lenses and VT; if VT fails, use cycloplegic agent temporarily; educate patient".[ quote citation needed ]

For more chronic and acute cases that do not respond to vision training and cycloplegic drops, the eye muscles should weaken with advancing age providing intermittent or permanent relief from this condition. [11]

See also

Related Research Articles

Glaucoma Eye disease in which high intraocular pressure damages the optic nerve

Glaucoma is a group of eye diseases that result in damage to the optic nerve and cause vision loss. The most common type is open-angle glaucoma, in which the drainage angle for fluid within the eye remains open, with less common types including closed-angle glaucoma and normal-tension glaucoma. Open-angle glaucoma develops slowly over time and there is no pain. Peripheral vision may begin to decrease, followed by central vision, resulting in blindness if not treated. Closed-angle glaucoma can present gradually or suddenly. The sudden presentation may involve severe eye pain, blurred vision, mid-dilated pupil, redness of the eye, and nausea. Vision loss from glaucoma, once it has occurred, is permanent. Eyes affected by glaucoma are referred to as being glaucomatous.

Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation. Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on nearby objects. This results in similar problems as those caused by presbyopia, in which the lens has lost elasticity and can also no longer focus on close-by objects. Cycloplegia with accompanying mydriasis is usually due to topical application of muscarinic antagonists such as atropine and cyclopentolate.

Presbyopia Medical condition associated with aging of the eye

Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Also known as age-related farsightedness, it affects many adults over the age of 40. A common sign of presbyopia is difficulty reading small print which results in having to hold reading material farther away. Other symptoms associated can be headaches and eyestrain. Different people will have different degrees of problems. Other types of refractive errors may exist at the same time as presbyopia. This condition is similar to hypermetropia or far-sightedness which starts in childhood and exhibits similar symptoms of blur in the vision for close objects.

Cyclopentolate Pair of enantiomers

Cyclopentolate is a muscarinic antagonist. It is commonly used as an eye drop during pediatric eye examinations to dilate the eye (mydriatic) and prevent the eye from focusing/accommodating (cycloplegic). Cyclopentolate or atropine can also be administered to reverse muscarinic and central nervous system effects of indirect cholinomimetic (anti-AChase) administration.

Eye surgery Surgery performed on the eye or its adnexa

Eye surgery, also known as ocular surgery, is surgery performed on the eye or its adnexa, by an ophthalmologist. The eye is a very fragile organ, and requires extreme care before, during, and after a surgical procedure to minimise or prevent further damage. An expert eye surgeon is responsible for selecting the appropriate surgical procedure for the patient, and for taking the necessary safety precautions. Mentions of eye surgery can be found in several ancient texts dating back as early as 1800 BC, with cataract treatment starting in the fifth century BC. Today it continues to be a widely practiced type of surgery, with various techniques having been developed for treating eye problems.

Pilocarpine Medication used to treat glaucoma and dry mouth

Pilocarpine is a medication used to reduce pressure inside the eye and treat dry mouth. As eye drops it is used to manage angle closure glaucoma until surgery can be performed, ocular hypertension, primary open angle glaucoma, and to bring about constriction of the pupil following its dilation. However, due to its side effects it is no longer typically used in the long term management. Onset of effects with the drops is typically within an hour and lasts for up to a day. By mouth it is used for dry mouth as a result of Sjögren syndrome or radiation therapy.

Intraocular lens Lens implanted in the eye to treat cataracts or myopia

Intraocular lens (IOL) is a lens implanted in the eye as part of a treatment for cataracts or myopia. If the natural lens is left in the eye, the IOL is known as phakic, otherwise it is a pseudophakic, or false lens. Such a lens is typically implanted during cataract surgery, after the eye's cloudy natural lens (cataract) has been removed. The pseudophakic IOL provides the same light-focusing function as the natural crystalline lens. The phakic type of IOL is placed over the existing natural lens and is used in refractive surgery to change the eye's optical power as a treatment for myopia (nearsightedness). This is an alternative to LASIK.

Ciliary body Part of the eye

The ciliary body is a part of the eye that includes the ciliary muscle, which controls the shape of the lens, and the ciliary epithelium, which produces the aqueous humor. The aqueous humor is produced in the non-pigmented portion of the ciliary body. The ciliary body is part of the uvea, the layer of tissue that delivers oxygen and nutrients to the eye tissues. The ciliary body joins the ora serrata of the choroid to the root of the iris.

Eye examination A series of tests assessing vision and pertaining to the eyes

An eye examination is a series of tests performed to assess vision and ability to focus on and discern objects. It also includes other tests and examinations pertaining to the eyes. Eye examinations are primarily performed by an optometrist, ophthalmologist, or an orthoptist. Health care professionals often recommend that all people should have periodic and thorough eye examinations as part of routine primary care, especially since many eye diseases are asymptomatic.

Cataract surgery Surgery for the eye

Cataract surgery, also called lens replacement surgery, is the removal of the natural lens of the eye that has developed an opacification, which is referred to as a cataract, and its replacement with an intraocular lens. Metabolic changes of the crystalline lens fibers over time lead to the development of the cataract, causing impairment or loss of vision. Some infants are born with congenital cataracts, and certain environmental factors may also lead to cataract formation. Early symptoms may include strong glare from lights and small light sources at night, and reduced acuity at low light levels.

Accommodation (eye) Focusing ability of eye

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies. In this, distances vary for individuals from the far point—the maximum distance from the eye for which a clear image of an object can be seen, to the near point—the minimum distance for a clear image. Accommodation usually acts like a reflex, including part of the accommodation-vergence reflex, but it can also be consciously controlled. Mammals, birds and reptiles vary their eyes' optical power by changing the form of the elastic lens using the ciliary body. Fish and amphibians vary the power by changing the distance between a rigid lens and the retina with muscles.

Ciliary muscle Eye muscle which is used for focussing

The ciliary muscle is an intrinsic muscle of the eye formed as a ring of smooth muscle in the eye's middle layer, uvea. It controls accommodation for viewing objects at varying distances and regulates the flow of aqueous humor into Schlemm's canal. It also changes the shape of the lens within the eye but not the size of the pupil which is carried out by the sphincter pupillae muscle and dilator pupillae.

Ciliary ganglion Bundle of nerve parasympathetic ganglion

The ciliary ganglion is a bundle of nerve parasympathetic ganglion located just behind the eye in the posterior orbit. It is 1–2 mm in diameter and in humans contains approximately 2,500 neurons. The ganglion contains postganglionic parasympathetic neurons. These neurons supply the pupillary sphincter muscle, which constricts the pupil, and the ciliary muscle which contracts to make the lens more convex. Both of these muscles are involuntary since they are controlled by the parasympathetic division of the autonomic nervous system.

Tropicamide Chemical compound

Tropicamide, sold under the brand name Mydriacyl among others, is a medication used to dilate the pupil and help with examination of the eye. Specifically it is used to help examine the back of the eye. It is applied as eye drops. Effects occur within 40 minutes and last for up to a day.

Polycoria is a pathological condition of the eye characterized by more than one pupillary opening in the iris. It may be congenital or result from a disease affecting the iris. It results in decreased function of iris and pupil, affecting the physical eye and visualization.

Pseudomyopia occurs when a spasm of the ciliary muscle prevents the eye from focusing in the distance, sometimes intermittently; this is different from myopia which is caused by the eye's shape or other basic anatomy. Pseudomyopia may be either organic, through stimulation of the parasympathetic nervous system, or functional in origin, through eye strain or fatigue of ocular systems. It is common in young adults who have active accommodation, and classically occurs after a change in visual requirements, such as students preparing for an exam, or a change in occupation.

Blurred vision Medical condition

Blurred vision is an ocular symptom where vision becomes less precise and there is added difficulty to resolve fine details.

Multifocal and accommodating intraocular lenses are artificial intraocular lenses (IOLs) that are designed to provide focus of both distance and near objects, in contrast to monofocal intraocular lenses which only have one focal point and correct distance vision. The issue of restoring accommodation following cataract surgery or through refractive lens exchange is becoming an increasingly important topic in ophthalmology.

Phacolytic glaucoma Medical condition

Phacolytic glaucoma (PG) is a form of glaucoma which is caused due to a leaking mature or immature cataract. Inflammatory glaucoma which occurs in phacolysis is a condition which is a result of the leakage of protein within the lens into the capsule of a mature or hyper mature cataract and involves a simple procedure to be cured that is referred to as cataract extraction.

Accommodative excess Medical condition

In ophthalmology, accommodative excess occurs when an individual uses more than normal accommodation for performing certain near work. Accommodative excess has traditionally been defined as accommodation that is persistently higher than expected for the patient's age. Modern definitions simply regard it as an inability to relax accommodation readily. Excessive accommodation is seen in association with excessive convergence also.

References

  1. ↑ Coroi, Mihaela Cristina; Bungau, Simona; Tit, Mirela (2015). "Preservatives from the Eye Drops and the Ocular Surface". Romanian Journal of Ophthalmology. 59 (1): 2–5. PMC   5729814 . PMID   27373107.
  2. ↑ Commissioner, Office of the. "FDA Basics - Is it legal for me to personally import drugs?". www.fda.gov. Retrieved 2019-01-24.
  3. ↑ "CLINICAL FINDINGS AND MANAGEMENT OF; ACCOMMODATIVE SPASM". www.aaopt.org. Retrieved 2019-01-26.
  4. ↑ "The Effectiveness of Vision Therapy in Improving Visual Function". Vision Help. 2014-10-30. Wold (78) reported on 100 children who had undergone accommodative vision therapy procedures. These clinically selected cases showed an 80% rate of improvement in accommodative amplitude and 76% in accommodative facility using a pre- and post-treatment ordinal criterion referenced scaling method. These results are similar to those reported by Hoffman and Cohen (168) a in which 70 patients were successfully treated for accommodative insufficiency and infacility based on clinical findings. Retrieved 2019-01-26.
  5. ↑ Gedar Totuk, Ozgun Melike; Aykan, Umit (2018). "A new treatment option for the resistant spasm of accommodation: clear lens extraction and multifocal intraocular lens implantation". International Journal of Ophthalmology. 11 (1): 172–174. doi:10.18240/ijo.2018.01.28. PMC   5767676 . PMID   29376009.
  6. ↑ Gabelt, B’Ann T.; Kaufman, Paul L.; Rasmussen, Carol A. (September 2011). "Effect of nitric oxide compounds on monkey ciliary muscle in vitro". Experimental Eye Research. 93 (3): 321–327. doi:10.1016/j.exer.2010.12.003. PMC   3299082 . PMID   21147103.
  7. 1 2 Cavet, Megan E.; Vittitow, Jason L.; Impagnatiello, Francesco; Ongini, Ennio; Bastia, Elena (14 August 2014). "Nitric Oxide (NO): An Emerging Target for the Treatment of Glaucoma". Investigative Ophthalmology & Visual Science. 55 (8): 5005–5015. doi: 10.1167/iovs.14-14515 . PMID   25125670.
  8. ↑ Zhao, Xiujun; Pearson, Keri E.; Stephan, Dietrich A.; Russell, Paul (1 May 2003). "Effects of Prostaglandin Analogues on Human Ciliary Muscle and Trabecular Meshwork Cells". Investigative Ophthalmology & Visual Science. 44 (5): 1945–1952. doi: 10.1167/iovs.02-0920 . PMID   12714628.
  9. ↑ Kim, Jaeyong; Kang, Huwon; Choi, Hakjoon; Jo, Ara; Oh, Dooi-Ri; Kim, Yujin; Im, Sojeong; Lee, Seul-Gi; Jeong, Kyeong-In; Ryu, Geun-Chang; Choi, Chulyung (19 July 2018). "Aqueous Extract of Perilla frutescens var. acuta Relaxes the Ciliary Smooth Muscle by Increasing NO/cGMP Content In Vitro and In Vivo". Molecules. 23 (7): 1777. doi: 10.3390/molecules23071777 . PMC   6100439 . PMID   30029520.
  10. ↑ "Care of the Patient with Accommodative and Vergence Dysfunction" (PDF). American Optometric Association. 2001. Archived from the original (PDF) on December 13, 2016. Retrieved January 25, 2019.
  11. ↑ Landolt, Edmond (1926). The refraction and accommodation of the eye and their anomalies. J.B. Lippincott Co. p. 450. OCLC   651960997.
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