Development of crossed eyes and inappropriate alignment of eyes in the same direction are the classical symptoms of strabismus. In addition to these, the eye disorder can also cause double vision, loss of vision, loss of perception of depth and difficulty in moving both the eyes together [6].

• Weakness

  If this muscle is weak, the eye tends to drift upwards. [pedseye.com]

  The recommendation for strabismic surgery is often oversimplified, such as "the weak eye muscles must be operated upon to realign the eye and correct the problem." [fretzvisiontherapy.com]

  The preoperative evaluation of these patients must be inclusive for restrictions, redirected muscle forces, adherence syndromes, muscle weakness, and visual sensory disturbance. [ncbi.nlm.nih.gov]

  In children, the brain tends to ignore the information sent from the weak eye. [symptoma.com]

  Usually this results from weakness of the muscles in one or both eyes. The weak eye will turn away from the object that it is supposed to be focused on. [bausch.com]

• Fatigue

  The eye muscles have a more complex fibre composition than other striated muscle, and they are among the fastest and most fatigue-resistant muscles in the body. [ncbi.nlm.nih.gov]

  Derivatives strabismic adjective Example sentences I have strabismic amblyopia in my right eye, and when I'm fatigued or stressed, my ‘lazy eye’ manifests; I have to concentrate to keep both eyes looking in the same direction. [web.archive.org]

  Fatigue, stress, or illness can sometimes cause temporary strabismus. [healthcommunities.com]

  These include: Poor depth perception Eye strain and/or pain Headaches Blurry or double vision Eye and/or general fatigue Patients with strabismus may report: difficulty driving, difficulty reading, difficulty with sports activities, feeling clumsier than [seevividly.com]

  Patient Symptoms The symptoms of strabismus are the effects that are noted by the patient and may include: Double vision Decreased depth perception Jittery vision Eye strain Headache Fatigue The brains response to the double vision that results from strabismus [news-medical.net]

• Inflammation

  No patient developed recurrence of inflammation or increased muscle restriction. [ncbi.nlm.nih.gov]

  They may occur suddenly if they result from an injury, inflammation or neurologic condition. Or they may appear to worsen or not improve if they have been present since birth. [childrensnational.org]

• Surgical Procedure

  Surgery to improve ocular alignment appears to herald major improvements in the quality of psychosocial functioning for the majority of adults undergoing such surgical procedures (P < 0.001). [ncbi.nlm.nih.gov]

  Fig. 1: Adult Strabismus, or misaligned eyes, can be surgically corrected. Is eye muscle surgery risky for adults? Every surgical procedure has some risks. [aapos.org]

• Trisomy 21

  Also, WRB is on chromosome 21, and children with trisomy 21 (commonly known as Down syndrome) have a higher incidence of strabismus, an intriguing connection. [sciencedaily.com]

• Jaundice

  Neonatal jaundice. Encephalitis. Meningitis. Cerebral palsy. Craniofacial abnormalities. Learning disabilities ± syndromes - eg, Down's syndrome and Turner syndrome. Fetal alcohol syndrome. [patient.info]

• Ulcer

  The most usual type, called a basal cell carcinoma (or “rodent ulcer”), starts as a small nodule in the skin that gradually enlarges and breaks down to form an ulcer with a hard base and pearly, rolled edges. [britannica.com]

  Corneal Exposure and Ulceration in Patients Treated With BOTOX ® for Blepharospasm Reduced blinking from BOTOX ® injection of the orbicularis muscle can lead to corneal exposure, persistent epithelial defect, and corneal ulceration, especially in patients [botoxmedical.com]

  In terms of therapeutic uses botulinum toxin has been found useful in treating facial muscle spasm, strabismus, nystagmus, corneal ulceration and exposure keratitis to name a few. [doi.org]

• Flushing

  The exposed Tenon's fascia can be trimmed flush with the conjunctival surface. Topical steroids can be used in cases where excision is not possible, and resolution typically occurs within days or weeks. [ncbi.nlm.nih.gov]

• Dermatitis

  Risk factors that predispose to this infection include low socioeconomic status; low level of overall hygiene; and local injury to skin caused by insect bites, scabies, atopic dermatitis, and minor trauma. [emedicine.medscape.com]

• Acne Vulgaris

  Eva Ritvo, James Q Del Rosso, Mark A Stillman and Christopher La Riche, Psychosocial judgements and perceptions of adolescents with acne vulgaris: A blinded, controlled comparison of adult and peer evaluations, BioPsychoSocial Medicine, 5, 1, (11), (2011 [doi.org]

• Strabismus

  Strabismus can be constant or intermittent. The misalignment also might always affect the same eye (unilateral strabismus), or the two eyes may take turns being misaligned (alternating strabismus). [allaboutvision.com]

  KEYWORDS: Conjunctiva/Tenon’s capsule; retractor; strabismus [ncbi.nlm.nih.gov]

  […] physiology Alternative Titles: heterotropia, squint Strabismus, also called squint, misalignment of the eyes. [britannica.com]

  Nonparetic strabismus is generally concomitant.[36] Most types of infant and childhood strabismus are comitant.[37] Paretic strabismus can be either comitant or noncomitant. [en.wikipedia.org]

• Esotropia

  © 2001-2016 Esotropia (inward turning of the eyes) Congenital Esotropia Infantile Esotropia Esotropia with Amblyopia Accommodative Esotropia Partially Accommodative Esotropia Esotropia can be divided into various categories each requiring a different [strabismus.org]

  Esotropia (crossed eyes) needs to be treated early in life to prevent amblyopia. [allaboutvision.com]

  It may be more effective in many subtypes of esotropia where surgery has been less reliable, including partially accommodative esotropia, esotropia associated with cerebral palsy, and thyroid eye disease. [ncbi.nlm.nih.gov]

• Diplopia

  The goal of surgery was elimination of diplopia in primary and reading position. [ncbi.nlm.nih.gov]

  Treatment is directed at restoring and maintaining ocular alignment, eliminating diplopia or visual confusion, enabling binocular vision, and restoring normal appearance. [bestpractice.bmj.com]

• Visual Impairment

  Screening for visual impairment in children ages 1 to 5: recommendation statement. January 2011. [bestpractice.bmj.com]

  At this point, the visual impairment will be termed "amblyopia," which is reduced visual acuity in the turned eye. [familyconnect.org]

  In this dataset, for individuals with strabismus and a coexisting visual impairment, it has been the visual impairment that is recorded in the single field addressing vision. [onlinelibrary.wiley.com]

  The Brain and Cerebral Visual Impairment 57. Perceptual aspects of Cerebral Visual Impairment and their Management Section 5: Selected Topics in Pediatic Ophthalmology 58. Ethics, morality and consent in Pediatric Ophthalmology 59. [elsevier.com]

  ‘Visual impairment caused by refractive error, amblyopia, strabismus, and astigmatism is a common condition among young children, affecting 5 to 10 percent of all preschoolers.’ [oxforddictionaries.com]

• Visual Impairment

  Screening for visual impairment in children ages 1 to 5: recommendation statement. January 2011. [bestpractice.bmj.com]

  At this point, the visual impairment will be termed "amblyopia," which is reduced visual acuity in the turned eye. [familyconnect.org]

  In this dataset, for individuals with strabismus and a coexisting visual impairment, it has been the visual impairment that is recorded in the single field addressing vision. [onlinelibrary.wiley.com]

  The Brain and Cerebral Visual Impairment 57. Perceptual aspects of Cerebral Visual Impairment and their Management Section 5: Selected Topics in Pediatic Ophthalmology 58. Ethics, morality and consent in Pediatric Ophthalmology 59. [elsevier.com]

  ‘Visual impairment caused by refractive error, amblyopia, strabismus, and astigmatism is a common condition among young children, affecting 5 to 10 percent of all preschoolers.’ [oxforddictionaries.com]

• Phenylketonuria

  B., Davidson, W., Lindsay, L. ( 1968 ) Phenylketonuria, mental development, behaviour and termination of low phenylaline diet. Journal of Paediatrics, 72, 646 – 655. Google Scholar | Crossref | Medline Harley, R. [doi.org]

• Stroke

  In older children and adults, crossed eyes can be caused by a variety of underlying medical conditions, like cerebral palsy or stroke. Crossed eyes can usually be corrected with corrective lenses, surgery, or a combination of both. [healthline.com]

  If the condition was caused by other factors, such as trauma or stroke, other symptoms will also be present and these are similar to those experienced following a stroke or damage to the brain, nerves, or eye muscles. [docdoc.com.sg]

  It is frequently a residual of a childhood onset but can occur in adults following a head injury, stroke, or as a part of systemic diseases such as diabetes and high blood pressure. [drguggino.com]

  In adults, strabismus may occur as a complication of an underlying disorder, such as diabetes mellitus, multiple sclerosis, cancer or stroke. Fatigue, stress, or illness can sometimes cause temporary strabismus. [healthcommunities.com]

  If the eyes become misaligned in an adult who did not have strabismus as a child, it could be a sign of a serious condition such as a stroke. A sudden, misalignment of the eyes or double vision are important reasons to see a doctor immediately. [medicinenet.com]

• Headache

  In addition to headaches and eye strain, symptoms may include an inability to read comfortably, fatigue when reading and unstable or "jittery" vision. [allaboutvision.com]

  Debbie had headaches and double vision. "After vision therapy headaches & double vision disappeared... also achieved better hand & eye coordination. This was 18 months ago. We are pleased with the therapy she has received. [kageyamavision.com]

• Confusion

  Treatment is directed at restoring and maintaining ocular alignment, eliminating diplopia or visual confusion, enabling binocular vision, and restoring normal appearance. [bestpractice.bmj.com]

  Visual Confusion. Strabismus in adults may also cause visual confusion, the perception of two different images superimposed onto the same space. [web.archive.org]

  In three of the four cases, strabismus surgery was successfully performed to avoid diplopia/confusion. All three patients revealed normal retinal correspondence. [ncbi.nlm.nih.gov]

  To avoid confusion, the brain usually will learn to ignore the image from the weaker eye. [youtube.com]

  Strabismus and amblyopia In strabismus, each eye sends a different image to the brain, which is confusing. [news-medical.net]

• Cerebellar Ataxia

  […] dysfunction, peripheral neuropathy, and progressive cerebellar ataxia. [frontiersin.org]

  Homepage Rare diseases Search Search for a rare disease Spinocerebellar ataxia type 40 Disease definition Spinocerebellar ataxia type 40 (SCA40) is a very rare subtype of autosomal dominant cerebellar ataxia type 1, characterized by the adult-onset of [orpha.net]

  SCA3 is a hereditary cerebellar ataxia that causes a degeneration of the cerebellum. There is damage created to the nerve cells and fibers that lead to the cerebellum’s damage. [lacaf.org]

  These 2 unusual cases exhibit a gradually progressive cerebellar ataxia syndrome plus features specifically associated with SCA2 (ie, slowed saccades) and SCA10 (ie, seizures). [jamanetwork.com]

  These patients presented with a form of cerebellar ataxia with slow saccadic eye movements4. [scielo.br]

• Tremor

  […] definition Spinocerebellar ataxia type 40 (SCA40) is a very rare subtype of autosomal dominant cerebellar ataxia type 1, characterized by the adult-onset of unsteady gait and dysarthria, followed by wide-based gait, gait ataxia, ocular dysmetria, intention tremor [orpha.net]

  […] parkinsonism, which has been reported in SCA2 cases.1 Hyperkinetic movement disorders have not been associated with SCA2 or SCA10 but may occur in other SCAs (eg, in SCA3, SCA6, SCA7, SCA14, SCA15, and SCA17), particularly as chorea, dystonia, myoclonus, or tremor [jamanetwork.com]

  Other common features included gait, stance, and limb ataxia, dysarthria, intention tremor, resting tremor, impaired smooth pursuit, and gaze-evoked nystagmus. [flybase.org]

  Muscle cramps and tremors can developpe too. Slurred speech, difficulty swallowing, and excessive muscle slackening might occur over time. [lacaf.org]

  Rarely, rigidity, tremors, and involuntary jerking movements (chorea) have been reported in people who have been affected for many years. [ghr.nlm.nih.gov]

At the preliminary level, a detailed physical examination of the eye will be carried out. This will be followed by various eye tests which would provide information about the extent of misalignment of the eyes. These tests include retinal exam, Hirschberg test, visual acuity, corneal light reflex and standard ophthalmic examination. In addition, neurological examination would also be performed to assess the neurological functioning [7].

Strabismus can be treated in several ways which include the following:

• Eye glasses or patch: Children with strabismus are prescribed eye glasses if required. Also, it is necessary to treat amblyopia at first and therefore a patch is recommended which covers the healthy eye and forces the child to see with the weak eye.
• Eye muscle surgery: When other treatment methods fail, eye surgery is usually the last resort. Through this surgery, the muscles of the eye will be made stronger or weaker depending on the condition. However, eye surgery would still require the child to wear glasses. It is also recommended that sooner the surgery is done better will be the outcome [8].
• Eye exercises are recommended for both children and adults with strabismus. This helps the eye muscles to strengthen and keep the eyes straight. 
• Botulinum toxin therapy was approved by the FDA way back in the year 1989 for treatment of strabismus in children over 12 years and adults. Children affected by infantile estropia benefit from this method. In this procedure, the toxin is injected in the stronger muscles in order to temporarily paralyze it [9] [10].

The prognosis of the condition post treatment is usually favorable. However, children and adults would continue to have vision problems. This may cause reading problems in children and adults would face difficulty while driving. Delay in treatment may lead to permanent vision loss in the weak eye. Follow up treatment and constant monitoring is a must as chances of recurrence of strabismus is high.

Strabismus is a common phenomenon both in children and adults. Failure of the eye muscles to work in coordination causes both the eyes to look in two different directions. Certain underlying disease conditions which can also lead to strabismus in children include cerebral palsy, Apert syndrome, retinoblastoma, congenital rubella, Noonan syndrome, Prader-Willi syndrome, traumatic brain injury, incontinentia iigmenti syndrome, trisomy 18 and development of hemangioma near the eye during infancy.

Various diseases associated with strabismus in adults consist of diabetes, botulism, stroke, eye injury, vision loss due to eye injury or disease, Guillain-Barré syndrome and shellfish poisoning. In addition to the above mentioned factors, heredity is also known to be a strong risk factor for development of strabismus [2].

It has been estimated that 4% of individuals in United States develop strabismus. Of the several forms of strabismus, estropia usually develops in the first decade of life [3]. It has also been reported that about 1/3rd of children with strabismus are at an increased risk of developing amblyopia.

Under normal conditions, the normal movement and alignment of human eye is governed by 6 muscles that work as a team. These ocular muscles help the eye to focus on the same object at same time. However, in instances when the muscles do not work appropriately it causes both the eye to look differently at two different objects.

As a result of this phenomenon, the brain receives information about 2 different objects. In children, the brain tends to ignore the information sent from the weak eye. In such situations, if strabismus is not promptly treated, then the brain will forever ignore information from the weak eye and as a result that eye will have poor vision. Such a condition is termed as amblyopia [4] [5].

So far there are no known methods of preventing strabismus. Its associated complications can however be prevented with early initiation of treatment.

When the eyes align inappropriately with each other, they are unable to focus together on the same point at the same time. Strabismus gravely affects the binocular vision and in turn affects the depth perception as well. A prompt treatment regime is required to correct the condition so that maximum vision acuity can be retained. Strabismus can be classified into 4 different types, depending on directional prefixes. These include estropia, exotropia, hypotropia and hypertropia [1].

Definition

Strabismus is an eye disorder characterized by inappropriate alignment of the eyes which does not allow both the eyes to focus at the same object at same time. An estimated 4% US population develops this eye disorder. Early initiation of treatment can help in preventing onset of complications.

Cause

A total of 6 eye muscles work in coordination to provide appropriate alignment to the eyes. When the muscles do not work as a team, then strabismus develops. In addition, certain underlying disease conditions such as diabetes, eye injury, stroke, eye disease, restinoblastoma, Noonan syndrome, Apert syndrome, congenital rubella, trisomy 18, cerebral palsy and Prader-Willi syndrome can also predispose children and adults to develop such a condition.

Symptoms

Crossed eyes and inappropriate eye alignment are the major symptoms experienced. In addition, individuals also experience poor vision, loss of vision, loss of depth perception and inability to move both eyes together.

Diagnosis

Diagnosis of strabismus begins with preliminary physical examination of the eyes. In addition, neurological examination is also carried out to assess the neurological functioning. Following this various eyes tests such as corneal light reflex, retinal exam, cover/uncover test, visual acuity and standard ophthalmic test are also performed.

Treatment

Treatment of strabismus includes prescribing eye glasses and patches to the children. In case, when these do not work then eye surgery is recommended. In addition to these methods, botulinum toxin injection is also employed for treating strabismus.

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2. Aurell E, Norrsell K. A longitudinal study of children with a family history of strabismus: factors determining the incidence of strabismus. Br J Ophthalmol 1990; 74:589.
3. Greenberg AE, Mohney BG, Diehl NN, Burke JP. Incidence and types of childhood esotropia: a population-based study. Ophthalmology 2007; 114:170.
4. Archer SM, Sondhi N, Helveston EM. Strabismus in infancy. Ophthalmology 1989; 96:133.
5. Mohney BG. Common forms of childhood esotropia. Ophthalmology. Apr 2001;108(4):805-9.
6. The eyes. In: Pediatric diagnosis: Interpretation of symptoms and signs in children and adolescents, 6th, Green M (Ed), WB Saunders Company, Philadelphia 1998. p.15.
7. Committee on Practice and Ambulatory Medicine, Section on Ophthalmology. American Association of Certified Orthoptists, American Association for Pediatric Ophthalmology and Strabismus, American Academy of Ophthalmology. Eye examination in infants, children, and young adults by pediatricians. Pediatrics 2003; 111:902.
8. Ho TH, Lin MC, Sheu SJ. Surgical treatment of acquired esotropia in patients with high myopia. J Chin Med Assoc. Aug 2012;75(8):416-9.
9. Birch E, Stager D, Wright K, Beck R. The natural history of infantile esotropia during the first six months of life. Pediatric Eye Disease Investigator Group. J AAPOS 1998; 2:325.
10. Fukai S, Arai N, Hayakawa T, Kimura H. Studies on the botulinum therapy for esotropia improvement of retinal correspondence. Nippon Ganka Gakkai Zasshi. Jun 1993;97(6):757-62.