Basic Pediatric Eye Exam
Additional Notes: Length 09:46
Posted September 11, 2020
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Basic Pediatric Eye Exam
This is Salma Dawoud and David Ramirez from the University of Iowa. In this video, we will provide an overview of basic pediatric ophthalmic examination techniques for medical students, interns and early ophthalmology residents.
We will discuss the general approach to examining children, stereopsis, the Worth four dot test, extraocular motility, confrontation visual fields, visual acuity, intraocular pressure, pupils, and the anterior segment and funduscopic exams. We will not discuss cover testing or retinoscopy; for these maneuvers, please see the EyeRounds tutorials at the following links.
Examination of a child involves a unique set of challenges. However, with patience, creativity, and flexibility, the exam can be performed successfully. Making the exam feel like a game is often very effective. This may involve using visually interesting toys and lights, asking silly questions, or examining a favorite stuffed toy. Remember, parents can also assist you during the exam.
The first step in the pediatric eye exam is measuring stereopsis, or depth perception. This is always performed first because it depends on intact fusion. Stereopsis testing should always be performed prior to cover testing as cover testing disrupts fusion and thus can affect stereopsis.
Test stereo in young children using stereo glasses. A traditional test is the Titmus fly test. The child should see the wings of the fly elevated above the page. When asked to pinch the wings, their fingers should remain above the page as shown here. Finer depth discrimination can be assessed with further testing, shown here using circles and animals.
If a child is uncooperative or refuses to wear glasses, the Lang test, which tests stereopsis without stereo glasses, may be a good alternative.
Worth four dot test
In pediatrics, the Worth four dot test is mainly used to assess for suppression. A full review of the applications of this test is beyond the scope of this video. To start, have the child wear red-green glasses, with the red lens over the right eye. Display the four dots of the Worth four dot test: 1 red dot, 2 green dots and 1 white dot. Perform the test at near and at distance. Starting with near using a Worth four dot flashlight, ask the child how many dots they see and what color they are. If they are shy, ask them to touch all the dots they see. Record their response and repeat for distance testing.
If there is no suppression present, they will see four dots: one red, two green, and one that alternates between red and green. They may also see two red and three green dots as the white dot will appear red or green depending on which eye is being used.
If the child is suppressing the left eye, they will only see the dots through a red filter. That is, they will only see two red dots, because the red lens filters out green dots.
If the child is suppressing the right eye, they will only see the dots through the green filter. That is, they will only see three green dots, because the green lens filters out red dots.
A shortcut to remembering these patterns is that the color of the dots the patient sees corresponds to the non-suppressed eye.
If the child sees four dots at near but suppresses at distance this may indicate that peripheral fusion is present.
Check motility by having the child look in the 6 cardinal directions of gaze. Toys and flashing lights can be helpful for tracking. Keep the head still if possible and make sure to check the extremes of gaze.
Confrontation Visual Fields
Confrontation visual fields can be tested in a similar manner. Cover one eye and hold an interesting object in one hand outside of the visual field. While having the child fixate on your nose, slowly move the object towards fixation and observe for a saccade. This indicates the field is intact. Test all four quadrants.
Next, we will assess visual acuity. Normal visual responses vary depending on the age of the child. At all ages, assessing for symmetry of vision or preference for one eye is critical.
In babies up to three months old, blinking or wincing to light is an appropriate response. Older infants should fixate on and follow a visual target with each eye independently.
For children under two years of age or in nonverbal children, vision is measured by describing whether it is central, steady, and maintained, or CSM. Centrality and steadiness are measured monocularly, while maintenance is measured binocularly.
To check for CSM vision in a child with misalignment, start by occluding one eye with an adhesive patch or a parent's hand. For children with nystagmus, do not patch; rather, use a frosted or fogged lens. If they have an abnormal head position, allow them to assume their preferred position. Notice if the child cries or objects to having one eye covered. An unequal objection to occlusion may reveal an eye preference.
Move an interesting object around fixation and determine whether the child fixates and tracks. If they do, this is said to be central. If not, it is said to be uncentral. Next, observe for nystagmoid or jerking movements. If absent, the eye is said to be steady. If not, it is unsteady. Finally, while having the child fixate, uncover the other eye and observe the movement. If the eye continues to follow the object, it is said to be maintained. If fixation changes to the uncovered eye, it is said to be unmaintained.
To check for CSM vision in patients with straight eyes or small misalignments, test for centrality and steadiness using the methods previously described. To check for maintenance, the vertical induced tropia test must be used. To perform this test, a 14-prism diopter prism is held in front of one eye, base-down, to induce a vertical deviation. Observe whether the child moves the eye to pick up the deviated image through this prism. Repeat for the opposite eye. A child with equal preference will have symmetrical responses between the eyes, or will rapidly alternate fixation while the prism is held up over either eye, as shown here. If one eye is favored, the child will prefer to hold gaze with that eye, regardless of the prism. Here is an example of the induced tropia test for a patient with a right eye preference. Notice how the left eye does not move when the prism is introduced.
Around two to three years old, children may be able to read a pictorial eye chart. Some common examples include LEA symbols and HOTV. Matching cards held in front of the child can help pre-verbal or shy children communicate what they see. You may use single optotypes but these MUST have crowding bars, particularly when testing amblyopic eyes.
Once children are familiar with letters of the alphabet – usually around age 5 – the traditional Snellen eye chart can be used.
Near vision should be tested with a near card using age-appropriate symbols or letters.
For shy or highly energetic children, encouragement and redirection are often necessary for accurate assessment of visual acuity.
Next, we will assess intraocular pressure with an iCare, which does not require numbing drops. Ask the child to look straight ahead. Rest the support pad on the patient's forehead and center the probe perpendicularly to the central cornea. Press the button to collect a measurement as the probe bounces off the cornea. If the reading is abnormal, it may be necessary to confirm with another tonometer, such as the Tonopen.
Next is the pupil exam. In many ways, this is identical to the adult pupil exam. However, there are important considerations for the pediatric population. Make note of the red reflex, ensuring it is present and equal in both eyes. Evaluate the pupils in light and dark environments while the child fixates on a distance target. Remember that children have profound pupillary constriction in response to accommodation for near targets. Perform the swinging flashlight test to assess for an afferent pupillary defect. Further discussion of this is detailed in a separate video. Beware of hippus, which is a normal, less than 1 mm, rhythmic fluctuation in pupillary size in young people.
Anterior Segment Exam
In young children or infants, the direct ophthalmoscope, the hand-held slit lamp or a 20-diopter lens may be a good option to examine the anterior segment. In older and more cooperative children, the slit lamp can be used.
Examine the fundus using indirect ophthalmoscopy. Once again, toys and videos are essential to distract the child and evoke gaze in a particular direction. Brief glances may be all that can be seen. If a child becomes frustrated, take a break or attempt the exam when the child has calmed down.
In children with concerns for pathology meriting a detailed exam not possible in clinic, an exam under anesthesia may be necessary.
This concludes the basic pediatric eye exam video.