Strabismus pdf

With normal vision, both eyes aim at the same spot. Our brain combines the two images from our eyes into a single, three-dimensional 3-D image. This is how we can tell how near or far something is from us called depth perception. When one eye is out of alignment, two different pictures are sent to the brain. In a young child, the brain learns to ignore the image of the misaligned eye.

Instead, it sees only the image from the straight or better-seeing eye. As a result, depth perception may be affected. Adults who develop strabismus after childhood often have double vision. This is because their brains have already learned to receive images from both eyes.

Their brains cannot ignore the image from the turned eye, so they see two images. You may also notice that your child closes one eye or tilts their head when looking at an object. Also, your child may squint with one eye when in bright sunlight. If you think your child might have strabismus, visit a pediatric ophthalmologist for a complete eye exam. When children are less than a year old, their eyes may look crossed when they really are not. Although the eyes appear misaligned, the light reflection is in the same place in both eyes.

A photograph showing an off-center reflection of light in left eye—a sign of strabismus. Babies and very young children with an inward turning eye esotropia may need surgery or glasses. Strabismus surgery on the eye muscles helps align eyes properly and allows good vision to develop. Children over 2 years old with esotropia, may be prescribed special eyeglasses to help focus and straighten the eyes. Occasionally prisms are used to help with focus as well.

A prism is a clear, wedge-shaped lens that bends refracts light rays. A prism can be attached to eyeglasses or made as part of the lens. Patching or blurring might be recommended to help strengthen a misaligned eye that is weaker than the other. The child is prevented from using their stronger eye by wearing an eye patch or using blurring eye drops. This forces them to use the weaker eye, helping to strengthen it over time.

Strabismus surgery is usually done in an outpatient surgery center. Your child will be given a general anesthesia to be fully asleep. The ophthalmologist makes a small cut in the tissue covering the eye to reach the eye muscles. In other cases, the eyes may alternate turning. Proper eye alignment is important to avoid seeing double, for good depth perception, and to prevent the development of poor vision in the turned eye.

When the eyes are misaligned, the brain receives two different images. At first, this may create double vision and confusion. But over time the brain will learn to ignore the image from the turned eye. Untreated, eye turning can lead to permanently reduced vision in one eye. This condition is called amblyopia or lazy eye.

Some babies' eyes may appear to be misaligned, but they are actually both aiming at the same object. This is a condition called pseudostrabismus or false strabismus. The appearance of crossed eyes may be due to extra skin that covers the inner corner of the eyes or a wide bridge of the nose. Usually, the appearance of crossed eyes will go away as the baby's face begins to grow. Strabismus usually develops in infants and young children, most often by age 3.

But older children and adults can also develop the condition. People often believe that a child with strabismus will outgrow the condition. However, this is not true. In fact, strabismus may get worse without treatment.

A doctor of optometry should examine any child older than 4 months whose eyes do not appear to be straight all the time. Strabismus can be caused by problems with the eye muscles, the nerves that transmit information to the muscles, or the control center in the brain that directs eye movements.

It can also develop due to other general health conditions or eye injuries. Many types of strabismus can develop in children or adults, but the two most common forms are below. Accommodative esotropia often occurs because of uncorrected farsightedness hyperopia. The eye's focusing system is linked to the system that controls where the eyes point. People who are farsighted are focusing extra hard to keep images clear.

The fixating eye is covered, and movement of the uncovered eye is noted both for distance and near. Uncover test: Uncover test detects heterophoria. After covering an eye for 2 to 3 seconds, the same eye movement is observed on uncovering. This test is done for both distance and near.

Alternate cover test: This is a dissociation test that reveals the total deviation when fusion is interrupted and should be performed only after the cover-uncover test. Patients with poor fusional control may decompensate to a manifest deviation when this test is done. The speed and smoothness of recovery are noted following a fast cover-uncover test done alternatively to both eyes.

Prism cover test: This test combines the alternative cover test with prism for both near and distant fixation. Maddox wing: This test dissociates the eyes for near fixation 33cm and measures heterophoria. When seeing through this instrument, the right eye sees only the arrows white vertical and red horizontal , while the left eye sees only rows of numbers horizontal and vertical.

The white arrow position denotes horizontal deviation, and a red arrow denotes the vertical deviation. By aligning the red arrow parallel to the horizontal row of a number, cyclophoria can be measured. Maddox rod: Maddox rod converts a white light spot into a perpendicular red streak by a series of fused cylindrical red glass rods. The amount of dissociation is calculated by the superimposition of the two images using the prisms. Ductions: Ductions are monocular eye movements elicited in all six cardinal positions by occluding the other eye.

Ductions are assessed if either or both eyes ocular motility limitations are noticed. Underaction is graded from -1 to -4 with increasing degrees of underaction, and 0 indicates full movement. It should be nearer than 10 cm. Near point of accommodation: Near point of accommodation NPA is the nearest point at which the eyes can maintain clear focus when tested with RAF rule. At 20 years of age, it is 8 cm and recedes to 46 cm by 50 years. Fusional amplitudes: Fusional amplitudes measure the efficacy of vergence movements and are tested with prism bars or synoptophore.

Postoperative diplopia test: This test is mandatory for all patients above seven years of age before strabismus surgery. Prisms larger than the planned correction for the deviation is placed in front of the deviating eye. If suppression is seen, then the risk of diplopia following surgery is less. Intermittent or constant diplopia is an indication to do diagnostic botulinum toxin tests before the surgery. Smaller chart: indicates the eye with the paretic muscle, and the greatest restriction is in the direction of the paretic muscle.

Larger chart: indicates the eye with an overacting muscle, and the greatest expansion is in the main direction of action of the yoke muscle. Following are the various methods of treating strabismus: Observation: Strabismus secondary to myasthenia gravis, diabetic mononeuropathy, and post-traumatic restrictive strabismus mostly improve with time and with the treatment of the primary cause. Recession, retro equatorial myopexy or posterior fixation Faden procedure , marginal myectomy, and myectomy disinsertion are some of the weakening procedures.

Strengthening Procedures: These procedures enhance the pull of the muscle. Resection, advancement, Double-breasting or tenoplication, and cinching are the strengthening procedures. Vector Adjustment Procedures. These are transpositioning procedures that alter the direction of muscle action. Differential Diagnosis Differential diagnoses can be classified on the basis of the type of defect.

Following are some important differentials to be considered: Congenital esotropia Early-onset accommodative esotropia. Prognosis Prognosis of strabismus is excellent if detected and managed early in life. Indications for ophthalmologist referral Altered pupillary reflex or leukocoria. Complications Complications of strabismus include the following: Amblyopia. Deterrence and Patient Education Parents should be made aware of the prognosis, advantages, and complications of the management of strabismus and its impact on the social, physical, and psychological growth of the child.

Enhancing Healthcare Team Outcomes The treatment of strabismus in children involves a multidisciplinary approach and might take place in a variety of locations. Review Questions Access free multiple choice questions on this topic. Comment on this article. Figure Strabismus surgery—medial rectus muscle being disinserted following pre-placement of polyglactin sutures. Figure Strabismus. Image courtesy S Bhimji MD. References 1. Resolution in partially accomodative esotropia during occlusion treatment for amblyopia.

Eye Lond. Roberts J, Rowland M. Refraction status and motility defects of persons years. Vital Health Stat Prevalence of amblyopia and strabismus in African American and Hispanic children ages 6 to 72 months the multi-ethnic pediatric eye disease study.

Mohney BG. Common forms of childhood esotropia. Common forms of childhood strabismus in an incidence cohort. Am J Ophthalmol. Incidence and types of childhood exotropia: a population-based study.

Cooper J. Intermittent exotropia of the divergence excess type. J Am Optom Assoc. The racial distribution of strabismus. A statistical study. Hawaii Med J.

Female predominance in intermittent exotropia. Monocular eye closure in sunlight. J Pediatr Ophthalmol Strabismus. Horwood A. Neonatal ocular misalignments reflect vergence development but rarely become esotropia. Br J Ophthalmol. Accommodative esotropia: the state of the art. Int Ophthalmol. Lavrich JB. Intermittent exotropia: continued controversies and current management. Curr Opin Ophthalmol. Optical treatment of strabismic and combined strabismic-anisometropic amblyopia.

Atropine vs patching for treatment of moderate amblyopia: follow-up at 15 years of age of a randomized clinical trial. JAMA Ophthalmol.

Ophthalmol Ther. Gray LS. The prescribing of prisms in clinical practice. Graefes Arch Clin Exp Ophthalmol.

Miotics vs glasses in esodeviation. Unnecessary surgery in fully refractive accommodative esotropia. Outcome study of stereopsis in relation to duration of misalignment in congenital esotropia. Maximum angle of horizontal strabismus consistent with true stereopsis.

The outcomes of horizontal strabismus surgery and influencing factors of the surgical success. J Med Assoc Thai. In: StatPearls [Internet]. In this Page. Related information.

Similar articles in PubMed. Review Ptosis Correction [StatPearls. Review Botulinum toxin for the treatment of strabismus. Cochrane Database Syst Rev. Epub Mar 2. Management of strabismus in nanophthalmic patients: a long-term follow-up report. Effect of refractive surgery on binocular vision and ocular alignment in patients with manifest or intermittent strabismus.

Epub Aug 2. Review The role of drug treatment in children with strabismus and amblyopia. Paediatr Drugs.