Pediatric Eye Examination

- Appendix 1

(Points of history taking and examinations)

➡️History Taking:

Thorough history taking is mandatory and should include the following:

    ▪️  Demographic data: including sex and date of birth

    ▪️  The chief complaint

    ▪️   Perinatal history: including maternal drug intake during pregnancy and/or lactation, gestational age at time of delivery, birth weight, history of NICU admission or any other neonatal intervention. This is important in infants and in special cases in older children.

    ▪️  Ocular history: including prior eye problems, diseases, diagnoses, treatment and surgeries

   ▪️  Systemic history: including history of hospitalization, surgeries and general health.

     ▪️  Current medications and allergies.

     ▪️  Family history of any related ocular or systemic conditions

➡️Examination

Documentation of the child’s level of cooperation in the examination can be useful in interpreting the results. The order of the examination may vary depending on the child’s level of cooperation. Testing of sensory function should be performed before using any dissociating examination techniques, such as covering an eye to check visual acuity or alignment. Binocular alignment testing should be done prior to cycloplegia. The examination should include the following elements:

       ▪️  Binocular red reflex (Brückner) test

      ▪️  Binocularity/stereo-acuity testing

      ▪️  Assessment of fixation pattern and/or visual acuity

       ▪️   Binocular alignment and ocular motility

      ▪️  Pupillary examination

      ▪️   External examination

      ▪️  Anterior segment examination

      ▪️   Cycloplegic retinoscopy/refraction

     ▪️  Funduscopic examination

➡️Binocular Red Reflex (Brückner) Test

To perform this test, the room is darkened, and the examiner sets the ophthalmoscope lens power at “0” and directs the ophthalmoscope light toward both eyes of the child simultaneously from approximately 50 to 75 centimeters. The Brückner test should be performed prior to pupillary dilation, because subtle differences in the red reflex are difficult to detect once the pupils are dilated (19). To be considered normal, a symmetric red reflex should be observed from both eyes. Opacities within the red reflex, a markedly diminished reflex, the presence of a white or dull reflex, or asymmetry of the red reflexes are all considered abnormal. The appearance of the red reflex varies based on retinal pigmentation and, thus, varies by race/ethnicity; therefore, the emphasis is on symmetry rather than the color of the reflex. Significant hyperopia will present as an inferiorly placed brighter crescent in the red reflex. Significant myopia presents as a superiorly placed brighter crescent (20).

➡️Binocularity/Stereoacuity Testing

Binocularity, or binocular vision, has several different components, including sensory fusion, stereopsis, fusional vergence (motor fusion), and other coordinated binocular eye movements. Sensorimotor fusion is sensitive to disruption by amblyopia, strabismus, refractive error, and deprivation. Binocular vision may be affected to different degrees depending on the underlying diagnosis, and tests to evaluate each of these components vary accordingly. The Worth 4-Dot Test is used to evaluate sensory fusion, the Randot Stereo Test is used to evaluate stereopsis, and a prism bar or rotary prism is used to evaluate fusional motor vergence (21,22) Assessment of stereoacuity is an important component of binocular alignment testing because high-grade stereoacuity is associated with normal alignment (23). Filter-free stereoacuity tests may be comparable to the Randot test and eliminate the need for polarizing lenses (24). Testing of sensory function should be performed before using any dissociating examination techniques (e.g., covering an eye to check monocular visual acuity or cover testing to assess alignment).

➡️Assessment of Fixation Pattern and Visual Acuity

Fixation:

Visual acuity measurement of the infant or toddler involves a qualitative assessment of fixation and tracking (following) eye movements. Fixation and following are assessed by drawing the child’s attention to the examiner or caregiver’s face or to a hand-held light, silent toy, or other fixation target and then slowly moving the target. Fixation behavior can be recorded for each eye as “fixes and follows” or “central, steady, and maintained through a smooth pursuit,” along with any qualifying findings, such as fixation that is eccentric, not central, not steady, or not maintained. Large differences in vision between the eyes can be detected by observing the vigor with which the child objects to occlusion of one eye relative to the other. Children resist covering an eye when the fellow eye has limited vision (25-27)

Grading schemes can be used to describe fixation preference. For strabismic patients, fixation pattern is graded binocularly by determining the length of time that the nonpreferred eye holds fixation. The eye will not hold fixation, holds momentarily, holds for a few seconds (or to or through a blink), or spontaneously alternates fixation.

For children with small-angle strabismus or no strabismus, the induced tropia test may be done by holding a base-down or base-in prism of 10 to 20 prism diopters over one eye and then over the other eye and noting fixation behavior (27-29) Studies have shown that these tests cannot stand alone as highly accurate screening tests for differentiating amblyopia from normal.(26, 30-32) However, when used in a clinical setting and interpreted in the context of other key findings, tests of fixation preference can be useful diagnostic tools to help determine whether there is amblyopia of sufficient severity to warrant treatment. Qualitative assessment of visual function should be replaced with a recognition visual acuity test based on optotypes (letters, numbers, or symbols) as soon as the child can perform this task reliably.

➡️Visual Acuity

Recognition visual acuity testing, which involves identifying optotypes and consisting of letters, numbers, or symbols, is preferred for assessment of visual acuity to detect amblyopia. The optotypes may be presented on a wall chart, computer screen, or hand-held card. Visual acuity is routinely tested at distance 3 to 6 meters and at near 35 to 40 centimeters. Visual acuity testing conditions should be standardized so that results obtained over a series of visits can be readily compared. High contrast charts with black optotypes on a white background should be used for standard visual acuity testing (33-34). A child’s performance on a visual acuity test will depend on the choice of chart and the examiner’s skills and rapport with the child, and on the child’s level of cooperation. To reduce errors, the environment should be quiet and free of distraction. Younger children may benefit from a pretest on optotypes presented at near, either at the start of testing or in a separate session.

Before monocular testing, the examiner should ensure that the child is able to perform the test reliably. Allowing children to match optotypes on the chart to those found on a hand-held card will enhance performance, especially in young, shy, or children with cognitive impairments. Visual acuity testing of children with special needs can provide quantitative information about visual impairment and reduce concerns of parents about the child’s vision (34). A shorter testing distance or flip chart can also facilitate testing in younger children (35).

Visual acuity testing should be performed monocularly and with best refractive correction in place. Ideally, the fellow eye should be covered with an adhesive patch or tape. If such occlusion is not available or not tolerated by the child, care must be taken to prevent the child from peeking and using the “covered” eye. Sometimes the child will not allow any monocular occlusion, in which case binocular visual acuity should be measured.

Monocular visual acuity testing for patients with nystagmus or latent nystagmus requires special techniques such as blurring the fellow eye with high plus lenses or using a translucent occluder rather than an opaque one. Binocular visual acuity testing can also be performed on these patients to gain additional information about typical visual performance.

An age-appropriate and consistent testing strategy on every examination is essential. The choice and arrangement of optotypes can significantly affect the visual acuity score obtained (36-37). Optotypes should be clear, standardized, and of similar characteristics, and they should not reflect a cultural bias (34).

LEA SYMBOLS® (Good-Lite Co., Elgin, IL, USA), a set of four symbols developed for use with young children, are useful because each optotype blurs similarly as the child is presented with smaller symbols, increasing the reliability of the test (36,39). Because they include only four possible responses, these acuity tests are easier for younger children. Children who cannot name them may match them using a hand-held card. Other charts like HOTV (36,40), Allen Figures, Lighthouse Chart, Kindergarten (Sailboat) Eye Chart can also be used (34,41)

For older cooperative children Landolt C chart or tumbling E chart can be used. The majority of optotypes must be correctly identified to “pass” a line. A similar number of optotypes on each line with equal spacing is preferred. In the setting of amblyopia, testing with single optotypes is likely to overestimate visual acuity(42,44) because of the crowding phenomenon; that is, it is easier to discriminate an isolated optotype than one presented in a line of optotypes. Therefore, a more accurate assessment of monocular visual acuity is obtained in amblyopia with a line of optotypes. In order to preserve the crowding effect of adjacent optotypes, optotypes should not be covered or masked as the examiner points to each successive optotype. If a single optotype must be used to facilitate visual acuity testing for some children, the single optotype should be surrounded (crowded) by bars placed above, below, and on either side of the optotype(45,47)

Forced choice preferential looking testing can provide an assessment of grating resolution visual acuity in some infants and preverbal children, and the patient’s acuity can be compared with normative data; this method overestimates recognition visual acuity in children with amblyopia(48,49)

➡️Binocular Alignment and Ocular Motility Assessment

The corneal light reflection, binocular red reflex (Brückner) test, and cover tests are commonly used to assess binocular alignment. Cover/uncover tests for tropias and alternate cover tests for the total deviation (latent component included) in primary gaze at distance and near should use accommodative targets. The cover test is performed by covering one eye and observing for a refixation movement of the fellow eye; if it occurs, then a tropia is present. Cover tests require sufficient visual acuity and cooperation to fixate on the desired target. Ocular versions and ductions, including into the oblique fields of gaze, should be tested in all infants and children. Eye movements may be tested using oculocephalic rotation (doll’s head maneuver) or assessed by observing spontaneous eye movements in the inattentive or uncooperative child. Binocular alignment testing should be done before cycloplegia, because alignment may change after cycloplegia.

➡️Pupillary Examination

The pupils should be assessed for size, symmetry, and shape; for their direct and consensual responses to light; and for presence of a relative afferent defect. Pupillary evaluation in infants and children may be difficult due to hippus, poorly maintained fixation, and/or rapid changes in accommodative status. Anisocoria greater than 1 millimeter may indicate a pathological process, such as Horner syndrome, Adie tonic pupil, or a pupil-involving third-cranial-nerve palsy. Irregular pupils may indicate the presence of traumatic sphincter damage, iritis, or a congenital abnormality (e.g., coloboma). A relative afferent pupillary defect (RAPD) of 0.3 or more log units (i.e., easily visible) is not typically seen in amblyopia. A subtle RAPD may be seen with dense amblyopia. The presence of a large RAPD should warrant a search for compressive optic neuropathy or other etiologies of visual impairment (e.g., retinal abnormality). (50)

➡️External Examination

The external examination involves assessment of the eyelids, eyelashes, lacrimal system, and orbit. The examination should include an assessment of ptosis, the amount of levator function, presence of eyelid retraction, and relative position of the globe within the orbit (e.g., proptosis or globe retraction, hypoglobus, or hyperglobus). Older children may tolerate measurement of globe position using an exophthalmometer. For uncooperative or younger children, proptosis of the globe may be estimated by comparing the position of the globes when viewing from above the head. The anatomy of the face (including the eyelids, interocular distance, and presence or absence of epicanthal folds), orbital rim, and presence of oculofacial anomalies should be noted. The position of the head and face (including head tilt, turn, or chin-up or chin-down head posture) should be recorded. Children who have prominent epicanthal folds and/or a wide, flat nasal bridge and normal binocular alignment often appear to have an esotropia (pseudoesotropia). Dysmorphic features need further evaluation.

➡️Anterior Segment Examination

The cornea, conjunctiva, anterior chamber, iris, and lens should be evaluated using slit-lamp biomicroscopy, if possible. For infants and young children, anterior segment examination using a direct ophthalmoscope, a magnifying lens such as that used for indirect ophthalmoscopy, or a hand-held slit-lamp biomicroscope may be helpful.

➡️Cycloplegic Refraction

Determination of refractive error is important in the diagnosis and treatment of amblyopia or strabismus. Patients should undergo cycloplegic refraction with retinoscopy, followed by subjective refinement of refraction when possible (51). Cycloplegic autorefraction has also been shown to be an accurate means of assessing the refractive error of children and can be used in conjunction with retinoscopy and subjective refinement (52). Care must be made to ensure that adequate time passes following installation of cycloplegia agents. Adequate cycloplegia is necessary for accurate retinoscopy in children because of their increased accommodative tone compared with adults. One study found that noncycloplegic refraction compared with cycloplegic refraction among school-aged children resulted in a measurement of 0.65 D more myopia on average (53). Uncommon short-term side effects of cycloplegic agents may include hypersensitivity reactions, fever, dry mouth, tachycardia, nausea, vomiting, flushing, somnolence, and, rarely, behavioral changes (i.e., delirium). Punctal occlusion may be useful to reduce these side effects. (54-56) If the reaction is severe, the child should be referred to an emergency care setting and physostigmine may be given. See appendix 2

➡️Funduscopic Examination

The optic disc, macula, retina, vessels, and the choroid should be examined, preferably using an indirect ophthalmoscope and condensing lens after adequate dilation is achieved. It may be impossible to examine the peripheral retina of the awake young child. If necessary, examination of the peripheral retina with an eyelid speculum and scleral depression may require swaddling, sedation, or general anesthesia.

➡️OTHER TESTS

Based on the patient's history and findings, additional tests or evaluations that are not part of the routine comprehensive ophthalmic evaluation may be indicated. Components that may be included if the child cooperates are the sensorimotor evaluation, assessment of accommodation and convergence, color-vision testing, measurement of intraocular pressure (IOP), and imaging. Photography of facial or ocular structural abnormalities may be helpful for documentation and follow-up.

➡️Sensorimotor Evaluation

A sensorimotor examination consists of measuring binocular alignment in more than one field of gaze with sensory testing of binocular function when appropriate, which includes testing of binocular sensory status (stereoacuity or Worth 4-Dot); assessing diplopia-free visual field; measuring ocular torsion (double Maddox rods); and/or assessing whether horizontal, vertical, and torsional components require correction in order to restore binocular alignment (using a prism or a synoptophore).

➡️Assessment of Accommodation and Convergence

Testing the near point of accommodation and convergence and determining accommodative and fusional convergence amplitudes can be helpful in children with reading concerns. In a recent study, convergence insufficiency was reported to be present in 2% to 6% of 5th and 6th grade children and accommodative insufficiency in 10% (57) Noncycloplegic retinoscopy provides a rapid assessment of accommodation and may be helpful in evaluating a child with asthenopia who has high hyperopia or a child at risk for accommodative dysfunction, such as cerebral palsy, Down syndrome, or other types of developmental delay. (58-59) Accurate accommodation when viewing a small target on or near the retinoscope is seen as a neutral retinoscopic reflex or small degree of “with” movement. In dynamic retinoscopy, the examiner evaluates the change in the retinoscopic reflex from a “with” motion toward neutrality when the patient shifts fixation from distance to the near target. (60-61)

➡️Color-Vision Deficiency Testing

Color-vision deficiency testing is usually performed with pseudoisochromatic plates, and children who cannot yet identify numbers can instead identify simple objects (62-63). Eight percent of males and less than 1% of females are color deficient. (64) Color-vision testing is not routinely performed in asymptomatic children but can be useful in symptomatic children or when there is a family history. When identified in a young child, it can be useful for their teachers to be aware that it may be difficult for them to accurately identify certain colors.

➡️Intraocular Pressure Measurement

Intraocular pressure measurement is not necessary for every child because glaucoma is rare in this age group and, when present, usually has additional manifestations (e.g., buphthalmos, epiphora, photosensitivity, and corneal clouding in infants; myopic progression in very young children; and enlarged optic cups). Intraocular pressure should be measured whenever a child has or is at risk for glaucoma. Because IOP measurement can be difficult in some children, a separate examination with the patient sedated or anesthetized may be required. The introduction of more compact instruments such as the Tono-Pen (Reichert, Inc., Depew, NY, USA), Perkins tonometer (Haag-Streit UK Ltd., Harlow, United Kingdom), and iCare rebound tonometer (iCare Finland Oy, Helsinki, Finland) have facilitated testing (65-66). One advantage of the iCare is that topical anesthetic drops are not required; however, overestimation of IOP sometimes occurs (67) Central corneal thickness measurement may be helpful in interpreting IOP because thicker corneas may cause artificially high IOP readings and vice versa. (68-70)

➡️Imaging

Photography or imaging in conjunction with the comprehensive pediatric eye examination may be appropriate to document and follow changes of facial or ocular structural abnormalities. Examples of indications to image include external photography for orbital or adnexal masses, strabismus, ptosis, or facial structure abnormalities; photography and optical coherence tomography to document cataract and other anterior segment anomalies; corneal topography to detect early changes related to keratoconus; ultrasound for vitreous and/or retinal pathology; and autofluorescence for optic nerve head assessment. Optical coherence tomography of the retinal nerve fiber layer/ganglion cell layer and of the retina may be considered in young children for conditions such as unexplained visual loss, risk of ocular toxicity from medication, glaucoma suspect, optic neuropathy, retinal dystrophies, and ROP.

Appendix 2

Recommended cycloplegic agents

Table 1:

Age	Recommended Agent	Dosage	Duration of Cycloplegia + Mydriasis	Side Effect Profile
Preterm to 3 months	Cyclomydril (cyclopentolate 0.2% and phenylephrine 1%)	Two sets of one drop separated by 5 minutes	6 – 48 hours	Minimal
3 months to 1 year	Cyclopentolate 0.5%	Two sets of one drop separated by 5 minutes	6-–48 hours+	Moderate
1 year to 12 years	Cyclopentolate 1%	Two sets of one drop separated by 5 minutes	6–48 hours+	Moderate
	Atropine 1% drops or ointment	One drop twice a day for 3 days	1–2 weeks+	High
12 years and older	Tropicamide 1% (may be used for younger children if cyclopentolate unavailable)	Two sets of one drop separated by 5 minutes	2–6+ hours	Low

 

At present, there is no ideal cycloplegic agent that has rapid onset and recovery, provides sufficient cycloplegia, and has no local or systemic side effects (54).  Cyclopentolate hydrochloride 1% is useful because it produces rapid cycloplegia that approximates the effect of topical ophthalmic atropine 1% solution but with a shorter duration of action (55). Cyclopentolate 1% solution is typically used in term infants over 12 months old. The dose of cyclopentolate should be determined based on the child's weight, iris color, and dilation history. In eyes with heavily pigmented irides, repeating the cycloplegic eyedrops or using adjunctive agents, such as phenylephrine hydrochloride 2.5% (which has no cycloplegic effect) or tropicamide 1.0%, may be helpful to achieve adequate cycloplegia and dilation to facilitate retinoscopy and ophthalmoscopy. (54).   Tropicamide (0.5%) and phenylephrine hydrochloride (2.5%) may also be used in combination to produce adequate dilation and cycloplegia. For children younger than 6 months, an eyedrop combination of cyclopentolate 0.2% and phenylephrine 1% is often used. (56). Some studies showed than low dose or very low dose phenylephrine and cyclopentolate microdrops for retinopathy of prematurity eye examinations may be sufficient (The Little Eye Drop Study): A randomised controlled non-inferiority trial. (71)

In some children, higher concentrations may be necessary, but should be with care of higher incidence of complications.

In rare cases, topical ophthalmic atropine sulphate 1% solution may be necessary to achieve maximal cycloplegia (55). The use of topical anesthetic prior to the cycloplegic reduces the stinging of subsequent eyedrops and promotes penetration of subsequent eyedrops. (57)

Appendix 3

Diagnosis and management points

When the eye examination is normal or indicates only a refractive error, and the child does not have risk factors for the development of eye disease, the ophthalmologist should establish an appropriate interval for re-examination. If re-examination has been determined to be unnecessary, patients should return for a comprehensive eye evaluation if new ocular symptoms, signs, or risk factors for ocular disease develop. Periodic vision screening should be continued. An evaluation every 6 months may be needed to evaluate progression.

When the history reveals risk factors for developing ocular disease or the examination shows potential signs of an abnormal condition, the ophthalmologist should determine an appropriate treatment and management plan for each child based on the findings and the age of the child.

When ocular disease is present, a treatment and management plan should be established, which may involve observation, eyeglasses, topical or systemic medications, occlusion therapy, eye exercises, and/or surgical procedures. The ophthalmologist should communicate the examination findings and the need for further evaluation, testing, treatment, or follow-up to parents/caregivers and the patient and the patient’s primary care physician or other specialists, as appropriate. Further evaluation or referral to other medical specialists may be advised.

Refractive correction is prescribed for children to improve visual acuity, alignment, and binocularity and to reduce asthenopia. Refractive correction plays an important role in the treatment of amblyopia and strabismus. Table 2 provides guidelines for refractive correction in infants and young children. Smaller amounts of refractive error may also warrant correction depending on the clinical situation. (SEE THE GUIDELINES ON MANAGEMENT OF REFRACTIVE ERRORS IN CHILDREN FOR MORE DETAILS)

Factors that help children to wear eyeglasses successfully include a correct prescription, frames that fit well, and positive reinforcement. Children require updates in eyeglasses much more frequently than adults owing to eye growth and associated changes in refraction. Infants and children with cerebral visual impairment or Down syndrome, and children on prescribed seizure medication may have poor accommodation and, therefore, require correction for smaller amounts of hyperopia compared with typically developing infants and toddlers.

For the youngest children, an evaluation every 6 months may be needed to evaluate progression.