FIGURE 29.6 Iris coloboma creating a “keyhole” pupil The iris defect is always inferior or inferior nasal The direct ophthalmoscope can be helpful in identifying iris anomalies The focusing dial should be turned so the iris is in focus (less than in away from the patient) The dial will be turning in the direction of increasingly higher black (or green) numbers to provide increasing magnification at shorter distances from the eye The red reflex test (see Chapter 114 Ocular Trauma ) can also be helpful when the pupil does not appear as a perfect circle Perhaps the most familiar disorder of pupillary shape and/or location is the congenital iris coloboma This “keyhole” pupil ( Fig 29.6 ) represents a failure of proper embryologic development of the iris tissue By itself, iris coloboma is usually asymptomatic and not associated with a functional deficit Associated colobomatous defects of the retina or optic nerve may exist, and these can result in serious visual compromise An eye with coloboma may be smaller (microphthalmia) Occasionally, when dilating drops are instilled initially, the pupil may begin to dilate irregularly and asymmetrically This is of no concern provided the ultimate shape of the dilated pupil is round Otherwise, it is wise to seek ophthalmology consultation in all situations of corectopia or irregular pupillary shape UNEQUAL PUPILLARY REACTIVITY Both pupils should be equally brisk in their constricting reaction to a penlight (or direct ophthalmoscope light) When asymmetry in pupillary reactivity is found, it is always the more sluggish pupil that is abnormal Often, the more sluggish pupil will be a unilaterally dilated pupil If both pupils are symmetric in their baseline positions, an abnormally sluggish pupil may indicate the presence of a serious retinal or optic nerve problem that is impairing the ability of the affected eye to perceive the light source equally Testing visual acuity is essential under these circumstances A Marcus Gunn pupil (also known as afferent pupillary defect [APD]) occurs when there is unequal perception of light between the two eyes, usually due to a unilateral or asymmetric optic neuropathy, which could be due to trauma, tumor (e.g., glioma in neurofibromatosis type 1), genetic optic neuropathies (e.g., Leber hereditary optic neuropathy), demyelinating disease, or inflammation of the optic nerve (papillitis) The reader is referred elsewhere for details of the “swinging flashlight test” used to evaluate for a Marcus Gunn pupil The pupil should not be pharmacologically manipulated in the ED if there is a concern about a pupil abnormality Rather, direct referral to an ophthalmologist is appropriate so the pupils may be observed unaltered Suggested Readings and Key References American Academy of Pediatrics, Section on Ophthalmology, American Association for Pediatric Ophthalmology And Strabismus, et al Red reflex examination in neonates, infants, and children Pediatrics 2008;122:1401– 1404 Biousse V, Newman NJ Neuro-Ophthalmology Illustrated Stuttgart, Germany: Thieme Verlag; 2009 Brodsky MC, Baker RS, Hamed LM Pediatric Neuro-Ophthalmology 3rd ed New York: Springer; 2016 Cahill JA, Ross J Eye on children: acute work-up for pediatric Horner’s syndrome Case presentation and review of the literature J Emerg Med 2015;48:58–62 Chapter Pediatrics In: Bagheri N, Wajda BN, eds Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease 7th ed Philadelphia, PA: Wolters Kluwer; 2017:177–203 Hamed LM Associated neurologic and ophthalmologic findings in congenital oculomotor nerve palsy Ophthalmology 1991;98:708–714 Jeffery AR, Ellis FJ, Repka MX, et al Pediatric Horner syndrome J AAPOS 1998;2:159–167 Miller NR Solitary oculomotor nerve palsy in childhood Am J Ophthalmol 1977;83:106–111 Thompson HS, Pilley SF Unequal pupils A flow chart for sorting out the anisocorias Surv Ophthalmol 1976;21:45–48 Young TA, Levin AV The afferent pupillary defect Pediatr Emerg Care 1997;13:61–65 CHAPTER 30 ■ EYE: VISUAL DISTURBANCES KAREN E DULL INTRODUCTION Sudden loss or deterioration of vision (or diplopia) can be caused by numerous diseases and injuries ( Tables 30.1 to 30.3 ) A systematic approach is necessary to reach a correct diagnosis and to minimize the risk of permanent visual impairment The patient’s age, underlying disease conditions, visual history, and history of possible injury must be determined The extent of the visual impairment, the rapidity of its onset, and the association with other systemic findings are vital pieces of information It is important to remember that visual acuity improves with age in children The normal visual acuity for a toddler is 20/40 and gradually improves to the normal adult acuity of 20/20 by age or years A careful eye examination, including gross and ophthalmoscopic examination, determination of extraocular movement, and visual acuity, together with the history, leads to correct diagnosis and management of the patient Few ocular conditions in the pediatric population are truly emergent ( Table 30.4 ), but many are urgent; most can be treated by the emergency physician or can be referred for appropriate follow-up with an ophthalmologist Many conditions seen by a pediatric ophthalmologist are not discussed here because they rarely are seen in the emergency department (ED) Conditions that are more likely to be seen in the ED are emphasized in this chapter PATHOPHYSIOLOGY Vision may be impaired through interference at any point in the visual pathway Light must reach the eye, pass through the cornea and the anterior chamber, be focused by the lens, pass through the posterior chamber, and reach the retina The retina must react to the visual stimuli, generate electrical impulses, and transmit these impulses along the optic nerve and eventually to the visual cortex for interpretation In addition, for binocular vision, the movement of both eyes must be coordinated and smooth Loss of clarity of the visual media or damage to the conductive tissues anywhere along the visual pathway can lead to decreased vision DIFFERENTIAL DIAGNOSIS Trauma and infections are the two most common causes of acute visual impairment that can interfere with any part of the visual pathway ( Tables 30.1 ... American Academy of Pediatrics, Section on Ophthalmology, American Association for Pediatric Ophthalmology And Strabismus, et al Red reflex examination in neonates, infants, and children Pediatrics 2008;122:1401–... Verlag; 2009 Brodsky MC, Baker RS, Hamed LM Pediatric Neuro-Ophthalmology 3rd ed New York: Springer; 2016 Cahill JA, Ross J Eye on children: acute work-up for pediatric Horner’s syndrome Case presentation... and review of the literature J Emerg Med 2015;48:58–62 Chapter Pediatrics In: Bagheri N, Wajda BN, eds Wills Eye Manual: Office and Emergency Room Diagnosis and Treatment of Eye Disease 7th ed