Assessment of Ocular Positioning and Movement It is often useful to start with assessment of the extraocular muscle movements This procedure is discussed in Chapter 28 Eye: Strabismus By using a toy or another interesting hand-held object, the clinician can entice the child to look in the direction in which the object is placed Both eyes should move equally in all directions The examiner should test upward and downward gaze as well as eye movements to the left and right The examiner can use the direct ophthalmoscope as a tool to accomplish several tasks without touching the child The ophthalmoscope light may be useful as a fixation target in testing eye movements, to assess whether the eyes are aligned (Hirschberg light reflex test, see Chapter 28 Eye: Strabismus ), to test for a red reflex (see Chapter 114 Ocular Trauma ), and as a simple hand-held magnifier While viewing through the ophthalmoscope, the focusing wheel can be dialed in the direction of the black or green numbers to allow the eyeball to come into focus regardless of the distance between the examiner and the patient Visual Acuity Testing Visual acuity testing is usually performed at a standardized distance Most standard wall charts are calibrated to be read at 20 ft, however there are eye charts calibrated to be read at 10 ft A patient can be placed 10 ft from an eye chart calibrated to be read at 20 ft and the results interpreted with an adjustment for this distance For example, the line marked 20/60 on the chart (a line that a person with normal sight can see at 60 ft but a person with that visual acuity would need to stand at 20 ft to see) becomes a 10/30 line when tested at a distance of 10 ft In some centers or with some vision charts, the metric system is used with 20 ft being equivalent to m As examples, vision of 20/20 is written as 6/6, 20/30 as 6/9, and 20/200 as 6/60 Visual acuity should be tested and recorded in each eye separately (i.e., with other eye occluded) and then with both eyes open FIGURE 123.1 A: HOTV visual acuity chart B: Picture visual acuity chart Chart selection is important when trying to obtain an accurate visual acuity Letter charts should be used only for patients who can clearly recognize the alphabet If there is any question by parental report, a number or picture chart should be used In general, the HOTV or picture visual acuity charts should be used for children to years ( Fig 123.1 ), and the Snellen number or letter chart for children years and older Vision assessment in infants and children less than years of age involves evaluating whether each eye can fix and follow objects A useful option for children who are not “in the mood” to verbalize their responses or are very shy is the use of matching acuity chart systems The two most common are the Sheridan Gardiner (Keeler Instruments, Inc., Broomall, PA) and HOTV (Precision Vision, La Salle, IL) In both situations, the child is holding a card that has all of the letters that are on the posted or hand-held chart 10 or 20 ft away The child need not know letters but can identify them as shapes For example, the H can be called a little ladder and the O a circle Instead of verbally responding, the child points to the matching shape (letter) on the card he/she or his/her parent is holding When using any visual acuity chart, it is not necessary to start with the largest symbol and have the patient read every symbol on every line thereafter Doing so risks losing the child’s attention Rather, one can start with the 20/20 line and then go to larger lines if the child is having trouble The child needs to recognize only a few letters on each line Minor errors such as the substitution of the letter F for the letter P, or the letter C for the letter O, may be tolerated It is almost an instinct for young children to use their better eye and suppress the vision in their lesser eye The examiner should ensure that it is not possible to peek with the nontested covered eye Therefore, children should not be allowed to cover their eye with their own hand (small cracks between the fingers can actually allow vision out of the “covered” eye) Children may also look around commercially available occluders for the same reasons Perhaps the best way to obstruct the vision in the eye not being tested is to use a broad piece of tape, ensuring the tape also covers the depression at the bridge of the nose ( Fig 123.2 ) To help ensure the patient is not “cheating,” the examiner should look back directly at the child while standing by the chart indicating the letters or pictures If the child has glasses they should be worn during visual acuity testing Any child who can read a chart but shows reduced visual acuity should be tested using a pinhole If vision improves with a pinhole then the patient only needs glasses and there is no organic abnormality causing the blurred vision After external examination and visual acuity are completed, the examiner can then proceed with other procedures as indicated, such as upper lid eversion and dilating the pupil These techniques, along with the proper methods of examining the retina and optic nerve using the direct ophthalmoscope, are discussed in Chapter 114 Ocular Trauma FIGURE 123.2 A broad piece of tape can be used to obstruct the vision of the eye not being tested If the tape is not adherent to the bridge of the nose, the child can peek out by turning the face to the side (right frame) Examining the Swollen Eye When the eyelids or periorbital tissue is edematous or the patient refuses to voluntarily open the eyelids, proper examination can be difficult The techniques described in Chapter 114 Ocular Trauma for opening the traumatized eye may be useful Warm compress can be used to gently loosen crust or discharge if present When there is mild to moderate swelling, the examiner can place his/her thumbs on the supraorbital and infraorbital ridges and gently apply pressure against the underlying bone while pulling fingers (and thus the eyelids) away from each other A Desmarres retractor can be helpful to control the upper eyelid and can also be applied simultaneously to the lower eyelids ( Fig 123.3A ) Commercially available speculums, when used in association with a topical anesthetic, are another painless and efficient way of opening the eyelids ( Fig 123.3B ) Importantly, when refusal to open an eye is secondary to pain (as with a corneal abrasion) instillation of topical anesthetic prior to examination will often lead to spontaneous eye opening In infants, the eyelids may be separated using cotton swabs The swabs should be placed at the midbody of the upper and lower eyelids As they are separated, pressure should be applied down against the eyelid and the swab should be rotated inward toward the eyelashes This will keep the eyelids in place so they not spontaneously evert and further obstruct the examiner’s view The cotton swab technique should not be used in patients being evaluated for eye trauma because pressure on the eyeball from this technique could cause further injury (see Chapter 114 Ocular Trauma ) Instillation of Eye Drops It may be necessary to instill certain eye drops to complete the eye examination (e.g., topical anesthetics, dilating drops) Instillation of eye drops can sometimes be difficult because of swollen eyelids or patient noncompliance Ophthalmic solutions are designed for a one-drop dose Drops are most efficiently delivered by pulling down the lower eyelid and placing the drop in the inferior fornix In patients who are extremely resistant, forced eyelid opening is needed to expose just a small strip of palpebral conjunctiva The eyeball itself does not need to be visualized An alternative technique involves placing the eye drop in the sulcus between the medial canthus and the side of the bridge of the nose while the patient is in the supine position Every child must eventually open his or her eyes and when this happens the eye drop will naturally flow onto the conjunctiva Topical anesthetics may be necessary to complete some parts of the examination, especially in the patient with significant pain Topical anesthetics should never be prescribed for outpatient use These are strictly diagnostic agents Prolonged use of topical anesthetics may result in corneal ulceration