Patients suffering from amblyopia or lazy eye will usually present with an eye that is wandering inward or outward during visual examination. There is a marked discordance between the two eyes which may appear that both eyes may not work in coordination with each other. Patients will start to note that they have markedly poor visual depth perception of solid objects and things. Amblyopia frequently affects a single eye but in certain cases, this can affect both eyes. The outward signs typically seen in amblyopia requires a meticulous eye examination by a qualified medical professional to detect.

• Disability

  Currently, such legislation is employed to identify accommodations needed for children with bilateral visual impairment and for children with dyslexia and/or related learning disabilities. [ncbi.nlm.nih.gov]

  Livingstone's research on developmental dyslexia also showed that "Visual abnormalities were reported to be found in more than 75% of the reading-disabled children tested." [children-special-needs.org]

  At least 12% of the population has some type of binocular vision disability. Amblyopia and strabismus are the most commonly known types of binocular vision disabilities. [vision3d.com]

  Please enable JS and disable any ad blocker [covd.org]

  Risk factors Factors associated with an increased risk of lazy eye include: Premature birth Small size at birth Family history of lazy eye Developmental disabilities Complications Untreated, lazy eye can cause permanent vision loss. [mayoclinic.org]

• Asymptomatic

  Posterior polymorphous corneal dystrophy is typically considered asymptomatic unless visual opacity develops. [ncbi.nlm.nih.gov]

  Often, these children appear to be asymptomatic because they are too young to express or unaware of a vision problem. Other signs of amblyopia include delay in gross motor coordination, poor depth perception, and poor academic performance. [visiontherapycalgary.com]

  Symptoms and Signs Amblyopia is often asymptomatic and is commonly uncovered only on routine vision screening. Children rarely complain of unilateral vision loss, although they may squint or cover one eye. [merckmanuals.com]

  Initial amblyopia may be asymptomatic. Only a specialist can detect this disorder. There is a special term defining the time when the effectiveness of amblyopia treatment is the highest known as the “sensitive period”. [eximer.ua]

  History Most cases of unilateral amblyopia are asymptomatic, as children do not notice the decreased visual acuity. In the United Kingdom, the majority of unilateral amblyopia is detected by vision screening programmes. [geekymedics.com]

• Fatigue

  These include: Poor depth perception Eye strain and/or pain Headaches Blurry or double vision Eye and/or general fatigue Unlike strabismus, which is easy to spot, you can’t detect amblyopia with simple observation, as there are no outward signs. [thevisiontherapycenter.com]

  Symptoms of amblyopia It is worth visiting a clinic as soon as possible if you notice the following alarming symptoms: Poor movement coordination, impaired spatial orientation; Rapid eye fatigue; Blurred objects; a kind of “shroud” in front of the eyes [eximer.ua]

  Children that are old enough to vocalize may complain of eye fatigue or headaches. The key to restoring proper vision is through early diagnosis and treatment. [kanataoptometry.ca]

  Typical symptoms include: Poor depth perception Difficulty catching and throwing objects Clumsiness Squinting or shutting an eye Head turn or tilt Eye strain Fatigue with near work A clue that your child may have amblyopia is if he or she cries or fusses [seevividly.com]

  Some signs and symptoms of astigmatism may include headache, eye strain, difficulty reading and fatigue. Depending upon the severity, eyeglasses or contact lenses may be required. [northwell.edu]

• Swelling

  A 7-month-old child presented with a 6-day history of right eyelid swelling and redness. She was being treated with chloramphenicol ointment and oral flucloxacillin by the general practitioner. [ncbi.nlm.nih.gov]

  Pain, swelling, or redness around the eye(s) Treatment of retinoblastoma may include: Surgery (removal of the eyeball which may be followed up with an artificial eye implant) Heat treatment (uses extreme heat directed toward cancer cells) Chemotherapy [northwell.edu]

  Trauma can lead to amblyopia through various processes - eg, prolonged lid swelling, presence of a vitreous haemorrhage or traumatic cataract. Prolonged occlusive dressing would have the same effect. [patient.info]

  An ophthalmologist examines the inside of your child’s eye to look for diseases or conditions like cataract inflammation (swelling) or tumors. Treatments Treatments Improved vision is the goal of ophthalmologic treatment. [rileychildrens.org]

• Pain

  She manifested a progressive visual loss after an episode of lumbar pain. [ncbi.nlm.nih.gov]

  These include: Poor depth perception Eye strain and/or pain Headaches Blurry or double vision Eye and/or general fatigue Unlike strabismus, which is easy to spot, you can’t detect amblyopia with simple observation, as there are no outward signs. [thevisiontherapycenter.com]

  The eye may feel dry, gritty and sore, but not painful. Read more on myDr website Glaucoma: what is it? - MyDr.com.au Glaucoma is the name given to a group of eye diseases in which the optic nerve at the back of the eye is slowly destroyed. [healthdirect.gov.au]

  Pain, swelling, or redness around the eye(s) Treatment of retinoblastoma may include: Surgery (removal of the eyeball which may be followed up with an artificial eye implant) Heat treatment (uses extreme heat directed toward cancer cells) Chemotherapy [northwell.edu]

• Nausea

  Other signs and symptoms may include headaches, nausea after reading, holding books close to one's face or writing with one's head very close to the table. [northwell.edu]

  […] sensations or moving backgrounds Moving objects appearing to have a trail behind them Not being able to focus for periods of time Difficulty changing point of focus Headaches or Migraines Poor hand-eye coordination Reduced peripheral vision Dizziness/nausea [mccrodanvision.com]

  I also suffered from severe daily headaches, dizziness, and nausea. After Vision Therapy, I can now do everything with two eyes and rarely get headaches. [visiontherapystories.org]

• Ulcer

  Dacryoadenitis - Epiphora - Dacryocystitis orbit : Exophthalmos - Enophthalmos Eyeball Conjunctiva Conjunctivitis ( Allergic conjunctivitis ) - Pterygium - Pinguecula - Subconjunctival hemorrhage Fibrous tunic sclera : Scleritis cornea : Keratitis - Corneal ulcer [psychology.wikia.com]

  These include: constant strabismus, or turning of one eye genetics, or a family history of amblyopia different levels of vision in each of your eyes damage to one of your eyes from trauma drooping of one of your eyelids vitamin A deficiency corneal ulcer [healthline.com]

  This type of amblyopia could be due to: a corneal ulcer, a scar, or another eye disease a congenital cataract, in which a baby is born with clouding of the lens ptosis, or a droopy eyelid glaucoma eye injury eye surgery Treatment tends to be more effective [medicalnewstoday.com]

• Strabismus

  strabismus usually causes double vision ( diplopia ), since the two eyes are not fixated on the same object. [psychology.wikia.com]

  Strabismus can be confirmed with the alternate cover test or the cover-uncover test (see diagnosis of strabismus ). Ophthalmologists can confirm anisometropia by doing a refraction on each eye. [merckmanuals.com]

  Our office specializes in strabismus and amblyopia. Dr. Cooper has trained over 500 doctors in the area of strabismus. [coopereyecare.com]

  Visit the most comprehensive site on What is Strabismus? on the internet! Also visit another doctor's page on strabismus on this site. [children-special-needs.org]

  There is frequently a family history of amblyopia or strabismus in the family. Amblyopia may be mild or moderate or severe. What Causes Amblyopia? The causes are varied and include: Strabismus (crossed eyed squint). [blackrock-clinic.ie]

• Esotropia

  Pigmentation may be one parameter because Caucasians are at higher risk for esotropia than non-whites. [ncbi.nlm.nih.gov]

  Total Surgery 3 48 F 106 L esotropia 0.475 0.000 0.000 Foveal Central Patching/surgery 4 38 M 114 R esotropia 0.125 −0.150 −0.150 Foveal Central Patching 5 64 F 106 L exotropia 0.200 −0.075 −0.075 Foveal Total Patching/surgery 6 58 F 109 R esotropia 0.250 [doi.org]

  These conditions include strabismus, in which the eyes are crossed inward ( esotropia ) or turned outward ( exotropia ) and anisometropia, in which there is a major difference in refractive error between the two eyes from nearsightedness, farsightedness [medicinenet.com]

  In esotropia, the eye is turned inwards. In exotropia, the eye is turned outwards. In hypertropia, the eye is turned upwards. In children, esotropia is most common and is associated with longsightedness (hyperopia). [vision-and-eye-health.com]

• Diplopia

  Oculomotor nerve disease is a common cause of diplopia. When strabismus is present, absence of diplopia has to induce the research of either uncovering of visual fields or monocular suppression, amblyopia or blindness. [ncbi.nlm.nih.gov]

  […] as lazy eye, usually results in normal vision in the fixating eye, but abnormal vision in the strabismic eye due to the brain receiving poorer quality input from that eye during development. [4] Adult-onset strabismus usually causes double vision ( diplopia [psychology.wikia.com]

• Visual Acuity Decreased

  In both normal eyes of 20 nonamblyopic patients and the fellow (non-amblyopic) eyes of 20 amblyopic patients, visual acuity decreased as the density of the prism-filter lens increased. [ncbi.nlm.nih.gov]

  Studies have shown that the number of patients who retain their level of visual acuity decreases over time to 53% after 3 years. [emedicine.com]

• Photophobia

  Rarely atropine drops can cause side effects such as flushing, tachycardia and photophobia. [geekymedics.com]

  […] ophthalmoplegia - One and a half syndrome Refractive error : Hyperopia / Myopia - Astigmatism - Anisometropia / Aniseikonia - Presbyopia Visual disturbances and blindness Amblyopia - Leber's congenital amaurosis - Subjective ( Asthenopia, Hemeralopia, Photophobia [psychology.wikia.com]

  Glaucoma that occurs in a child is called childhood glaucoma.Signs and symptoms of glaucoma may include excessive tearing, light sensitivity (photophobia), closure of one or both eyes in the light, cloudy enlarged cornea, one eye may be larger than the [northwell.edu]

• Headache

  This may be more noticeable if the child is tired or unwell being clumsy or having poor hand to eye coordination screwing up their eyes or shutting an eye complaining about double vision, or having unexplained headaches. [lookafteryoureyes.org]

  I also suffered from severe daily headaches, dizziness, and nausea. After Vision Therapy, I can now do everything with two eyes and rarely get headaches. [visiontherapystories.org]

  This can cause difficulties in reading and learning, sports, depth perception, and symptoms such as headaches. [mccrodanvision.com]

  Children that are old enough to vocalize may complain of eye fatigue or headaches. The key to restoring proper vision is through early diagnosis and treatment. [kanataoptometry.ca]

  Other signs and symptoms may include headaches, nausea after reading, holding books close to one's face or writing with one's head very close to the table. [northwell.edu]

• Dizziness

  Strabismus as a result of poor muscle strength in the eye is less common.The signs and symptoms of strabismus may include a child squinting their eyes, a child that cannot properly judge distance to pick up objects, a child that closes one eye to see better, dizziness [northwell.edu]

  Swimming sensations or moving backgrounds Moving objects appearing to have a trail behind them Not being able to focus for periods of time Difficulty changing point of focus Headaches or Migraines Poor hand-eye coordination Reduced peripheral vision Dizziness [mccrodanvision.com]

  I also suffered from severe daily headaches, dizziness, and nausea. After Vision Therapy, I can now do everything with two eyes and rarely get headaches. [visiontherapystories.org]

• Vertigo

  Interactions of amblyopia with visual vertigo. Westall and Schor (1984, 1985) wrote about adaptation of the vestibular system in persons with amblyopia. [dizziness-and-balance.com]

  […] to concentrate Short attention span Frequent loss of place Squinting, rubbing, closing or covering an eye Sleepiness during the activity Trouble remembering what was read Words appear to move, jump, swim or float Problems with motion sickness and/or vertigo [mccrodanvision.com]

• Mydriasis

  Quadrantanopia ) - Color blindness ( Achromatopsia, Dichromacy, Monochromacy ) - Nyctalopia ( Oguchi disease ) - Blindness / Low vision Pupil Anisocoria - Argyll Robertson pupil - Marcus Gunn pupil / Marcus Gunn phenomenon - Adie syndrome - Miosis - Mydriasis [psychology.wikia.com]

  In a few children whose eyes were slow to dilate, 2.5% phenylephrine hydrochloride was used to maximize mydriasis. Cycloplegia was considered full when pupils were fixed and 6 mm or larger in diameter. [jamanetwork.com]

Amblyopia or lazy eye are commonly diagnosed clinically during a thorough eye examination. The different tests implored for the diagnosis of amblyopia is dependent on the age group of the patient:
Neonates – By flashing a penlight over the eyes of the newborn, a glaring red eye reflex may be seen connoting that are no impending congenital cataract in the eye that may advertently lead to amblyopia.
Infants – Infants are clinically tested for their inherent ability to gaze and follow moving objects with their eyeballs. This practical test will reveal the presence of strabismus among high risk patients.
Toddlers – The red reflex test is fervently done on toddlers to detect cataract formation. Photo screening and auto refraction is also implored to detect this visual anomaly [7].
Preschoolers – The older children will benefit from tests that makes use of pictures and letters. Both eyes are alternatively patched to check both eyes for visual defects at this age.

By convention, amblyopia is treated in early childhood especially during the period where the brain and eye connections are starting to take form. The treatment options available for amblyopia is dependent on cause and the degree to which the child’s vision is affected. The following treatment options are available for amblyopia or lazy eye:

• Eye patches – Eye patches may be worn over the child’s stronger eye to help visually stimulate the weaker eye and its visual pathways to the brain [8]. 
• Eye drops – Patients suffering from amblyopia are given atropine drops on the normal eye one daily or twice weekly to blur the vision of the normal eye [9]. This will encourage the patient to use the other eye as well.
• Corrective spectacles – This corrective glasses can by prescribed to the patient by the ophthalmologist to allay symptoms of lazy eye especially when it is caused by conditions like nearsightedness, farsightedness, or astigmatism [10].
• Ophthalmic surgery – Amblyopia that are considered severe with eyes that are wondering may sometimes require surgery for the repair of the ocular muscles.

The earlier amblyopia is diagnosed and brought for professional medical intervention the sooner it is corrected. Amblyopia is no longer curable beyond the age of 8 years old when the visual pathways have reached full maturity. Best visual improvements are seen among patients who are treated before the fifth year of life. Treatments initiated when the child has not yet reached 2 years of age are likely to achieve full and complete recovery of the visual impairment.

Clinically, any medical condition that blur’s the visual field or cause the eye to cross can possibly cause lazy eye or amblyopia. The following common causes can lead to Amblyopia:
Strabismus – This is the most common cause of amblyopia or lazy eye. Strabismus is clinically defined as an imbalance in the muscles that can make the eyes lead out or crossed externally [1].
Visual Deprivation – Lazy eye consequently develops in an eye when the other eye is deprived of vision like those found in cataract cases [2]. Clinical conditions associated with visual deprivation include congenital cataract, corneal opacities, and ptosis [3].
Eye Refraction – Amblyopia results when there is a significant difference between the visions both eyes. Common causes include nearsightedness, farsightedness, and astigmatism of the eye surface.

The worldwide statistics for amblyopia is only 2-3% among children. They are found to occur predominantly before the second year of life. This visual anomaly may still be found in children up to the age of 8 years old although infrequent. Children are best treated before the age of 8 years old but in some cases, amblyopia persist until late childhood and adulthood which may now be very difficult to correct. There is no racial and sexual predilection found in amblyopia.

The pathophysiology of primary amblyopia is referred to as a developmental disease of the brain rather than as an organic disease of the eyeball. Although some cases of amblyopia can result from an on-going organic problem that may persists long after the primary organic disease process has been resolved [4]. In cases where there are opacities that block visual images from the affected eye, the neural pathway becomes incompletely stimulated on one side. This disruption in the pathway will lead to the incomplete development of the affected visual cortex in the brain [5]. The stage in neural development that is grossly affected in amblyopia completely develops at the age of two, thus the visual pathways are most susceptible and fragile within the first two years of life [6].

The early detection and treatment of amblyopia or lazy eye among the young children can greatly prevent permanent visual loss, It is imperative that all children should at least undergo one professional eye check-up between the age of 3 and 5 years old. Patients suspected of eye defects who are too young to speak should be brought to an eye specialist for a prompt eye evaluation.

The eye impairment found in Amblyopia is primarily due to the abnormal visual development occurring during the infancy or early childhood periods of growth. When amblyopia is left unchecked, an observable mild to moderate visual impairment is seen even among the younger age groups. Lazy eye develops when the nerve pathways between the brain and the eye is impaired causing the brain to ignore the defective eye and focuses on the functional eye. The consequent neural exclusion of the impaired eye makes it appear wandering externally and deviant from the actual object in focus, thus coined a “lazy eye”.

• Definition: Amblyopia or lazy eye is clinically defined as the inability to see clearly through one eye due to an abnormal development in visual pathway in the brain.
• Cause: Amblyopia is commonly brought about by any form of sight deprivation in one of the eyes. This can also be caused by strabismus and eye refraction. 
• Symptoms: Patients with amblyopia or lazy eye will often times present with a wandering eye which deviates outwardly or inwardly. Eye coordination is markedly discordant in this condition. 
• Diagnosis: The diagnosis of amblyopia is clinched through the early screening of the eyes for children. Red reflex is arbitrarily done especially during infancy. Photo screening and auto refraction can also be done to diagnose the disease.
• Treatment and follow-up: Patients will benefit from eye drops and eye patches to temporarily deprive the stronger eye with normal vision and enhance the poorer eye. Corrective glasses can also be indicated to relieve the disease condition. Ophthalmic surgery may also be indicated to radically correct the visual impairment.

1. Kushner, BJ. Amblyopia. In: Nelson LB, ed. Harley's Pediatric Ophthalmology. 1998:125-39.
2. Angell et al., Robb, RM, Berson, FG (1981). "Visual prognosis in patients with ruptures in Descemet's membrane due to forceps injuries". Arch Ophthalmol 99 (12): 2137–9.
3. Lin LK, Uzcategui N, Chang EL. Effect of surgical correction of congenital ptosis on amblyopia. Ophthal Plast Reconstr Surg. Nov-Dec 2008; 24(6):434-6.
4. McKee, SP., Levi, DM. Movshon, JA. (2003). "The pattern of visual deficits in amblyopia". J Vision 4 (5): 380–405.
5. Lempert P. Retinal area and optic disc rim area in amblyopic, fellow, and normal hyperopic eyes: a hypothesis for decreased acuity in amblyopia. Ophthalmology. Dec 2008; 115(12):2259-61.
6. Jeffrey Cooper & Rachel Cooper. "All About Strabismus". Optometrists Network. Retrieved 9 March 2008.
7. McNamara D. Laser scanner tops comparison of preschool vision screens. Medscape Medical News. April 15, 2013.
8. Holmes, Repka, Kraker & Clarke (2006). "The treatment of amblyopia". Strabismus 15 (1): 37–42.
9. Wright, Kenneth W.; Spiegel, Peter H.; Thompson, Lisa S. (2006). Handbook of Pediatric Strabismus and Amblyopia. New York, New York: Springer. ISBN 978-0-387-27924-4.
10. Taylor K, Powell C, Hatt SR, Stewart C. Interventions for unilateral and bilateral refractive amblyopia.Cochrane Database Syst Rev. Apr 18 2012;4:CD005137.