Fig. 3. Allen chart (A) and Osterberg chart (B) used to assess vision in verbal children who do not know the alphabet. (From Kniestedt C, Stamper RL. Assessing visual function in clinical practice. Ophthalmol Clin North Am 2003;16:166; with permission).

processes that are particular to, or more common in, the pediatric age group.

Conjunctivitis

Ophthalmia neonatorum (neonatal conjunctivitis)

Ophthalmia neonatorum is defined as conjunctivitis within the first month of life. There are three main types of neonatal conjunctivitis: chemical, bacterial, and viral. Although these entities may present with similar symptoms, the timing of the development of symptoms can often be a useful diagnostic clue. Chemical conjunctivitis secondary to perinatal ocular prophylaxis generally presents within the first 24 to 48 hours of life [6]. Erythromycin ointment is the agent most commonly used today and only rarely causes chemical conjunctivitis. Silver nitrate was used in the past and has been more frequently associated with chemical conjunctivitis. Infants with chemical conjunctivitis typically present with bilaterally inflamed lids and

watery discharge. Gram stain reveals white cells without bacteria. Treatment initially is supportive and involves the discontinuation of any ophthalmic medications and observation, with an expected resolution of symptoms within 48 hours. If no improvement is seen, a culture should be obtained and topical antibiotic therapy initiated, with care to avoid whatever agent was used for initial prophylactic therapy.

The epidemiology of neonatal infections is related to the transmission of organisms at the time of delivery; therefore, pathogens found in the genital tract and enteric system should be suspected. Chlamydia trachomatis is more commonly acquired from the birth canal than are Neisseria gonorrhoeae and herpes viruses (herpes simplex virus [HSV]) [7]. In addition, gram-negative enteric organisms and several staphylococcus and streptococcus species may also be acquired periand postnatally. Gonorrheal infections typically occur 2 to 5 days after birth but can be delayed if neonatal prophylactic therapy provides partial suppression. Chlamydial infections present slightly later, often between 5 and 14 days of life [6].

Physical examination findings can be helpful with diagnosis, but there is tremendous overlap of symptoms from di erent pathogens. Accurate diagnosis on the basis of physical examination alone is challenging and often requires supplementary laboratory data. Gonorrheal infections are classically characterized by a hyperacute mucopurulent discharge with lid edema, bulbar conjunctivitis, and chemosis. Chlamydial infections can also present with copious discharge but more commonly are characterized by palpebral conjunctival injection and inflammation with less associated lid edema and thick discharge [6,8]. A statim Gram stain and culture, including chocolate agar, should be obtained to aid in the diagnosis but should not delay the initiation of therapy when a high clinical suspicion for disease is present. In addition to Gram stain and culture, Giemsa stain, direct fluorescent antibody, ELISA, and polymerase chain reaction can be used to diagnose chlamydial infections, and laboratory investigation should be guided based on method availability [9]. Intracellular gram-negative diplococci are consistent with gonorrheal infection and constitute an ocular emergency because this organism can penetrate through and ulcerate the cornea, rapidly causing blindness [8]. An ophthalmology consult should be obtained immediately without delay in therapy. Current recommendations for treatment are a single dose of intravenous or intramuscular ceftriaxone with admission and hourly saline eye lavage. The infant should simultaneously be covered for chlamydial disease until cultures are negative using oral erythromycin therapy to treat ophthalmic disease and prevent the late onset of chlamydial pneumonitis [7,8].

Staphylococcus aureus, Streptococcus epidermis, Haemophilus influenzae,

Escherichia coli, and Pseudomonas are other causes of neonatal conjunctivitis and typically present from 5 to 7 days of life. Clinical findings are often indistinguishable from that of other pathogens. Diagnosis is by Gram stain and culture, and polymyxin/bacitracin/neomycin topical ointment is generally accepted as standard treatment. Diagnosis of typeable Haemophilus

influenzae conjunctivitis is an exception and should be treated with systemic antibiotics, with consideration given to a full septic evaluation before parenteral antibiotic administration.

Neonatal conjunctivitis caused by HSV, typically, although not exclusively, HSV-2, may also be acquired through the birth canal, and ocular manifestations may be the only presenting symptoms of neonatal herpetic infections [6]. Clinical suspicion should be elevated with a maternal history of infection, vesicular blepharitis, or the presence of ocular dendritic ulcers with fluorescein staining. Diagnosis is made by immunofluorescence, smear, or culture. Treatment involves both topical and systemic parenteral acyclovir and the avoidance of steroids. Full septic evaluation should be performed in the neonate with HSV infection [10].

Childhood conjunctivitis

Acute conjunctivitis is the most common eye disorder in young children and is the most frequent ophthalmologic complaint seen in the pediatric emergency department [11]. To date, there are no evidence-based guidelines for the diagnosis and empirical treatment of conjunctivitis [12]. Bacterial infections are predominant and are chiefly caused by one of three pathogensd non-typeable Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus [7,11]. The clinical course of bacterial conjunctivitis generally has an abrupt uniocular onset, with spread to the opposite eye within 48 hours [13]. Tearing and irritation are the initial symptoms, followed by mucopurulent discharge, typically with a history of crusting or gluing of the eyelashes. Di use erythema of the bulbar and palpebral conjunctivae is generally present, whereas preauricular lymphadenopathy is not [14].

Laboratory studies to determine the causative organism are usually reserved for severe cases and those unresponsive to initial treatment. Empiric treatment is commonplace, particularly when a history of sticky eyelids is obtained in conjunction with a physical finding of purulent discharge [12]. Treatment typically involves erythromycin ointment, bacitra- cin-polymyxin B ointment, or topical fluoroquinolones [7]. Several clinical associations can also help guide diagnosis and subsequent treatment. Conjunctivitis-otitis syndrome is common, occurring about 25% of the time, and is most often associated with non-typeable Haemophilus influenzae infections [11,15]. In this scenario, monotherapy with systemic antibiotics is indicated, and a topical agent is not needed [16,17]. Several studies suggest that if Haemophilus influenzae is recovered from a culture, or if the patient has a history of recurrent otitis media, systemic treatment should be initiated even in the absence of acute otitis media in the hope of preventing its development [17].

Another common cause of pediatric conjunctivitis is viral illness. The overall frequency of pediatric viral illness is extremely high, but the presence of conjunctivitis in systemic pediatric viral disease varies. The most common

type of viral conjunctivitis in children is adenoviral conjunctivitis, which can present as an isolated condition or as part of a viral syndrome [7]. Adenovirus can cause a nonspecific acute conjunctivitis characterized by red profusely watery eyes, or more severely, epidemic keratoconjunctivitis if corneal involvement is present. Pharyngoconjunctival fever caused by adenovirus is common in children and presents with the triad of pharyngitis, fever, and conjunctivitis, as the name implies. The typical course lasts 2 weeks and often begins with unilateral involvement, becoming bilateral within several days, with preauricular lymphadenopathy [18]. Although the typical course of pharyngoconjunctival fever is self-limited with an excellent prognosis, the same adenovirus types can also cause the rarer but more serious disseminated adenoviral disease which results in multisystem organ failure and death [18,19]. Upper respiratory tract infections caused by rhinovirus, enterovirus, and influenza virus are accompanied by a self-limited conjunctivitis less than 50% of the time, and less than one third of respiratory syncytial virus infections are accompanied by conjunctivitis. Conjunctivitis is also commonly associated with measles, although this pathogen is now rare in the United States [19].

The diagnosis of adenoviral conjunctivitis remains primarily clinical. Conjunctival hemorrhage can occur with adenoviral infection, as can punctate corneal epithelial defects; therefore, the slit lamp examination is an important part of the diagnostic evaluation, although it is often di cult to perform on a young patient. An ideal laboratory study does not yet exist. Viral cultures are epidemiologically useful, but delayed results have little use in the emergency department setting. Enzyme immunoassay and polymerase chain reaction tests are rapid, but the sensitivity varies considerably. Treatment options are also limited and are largely supportive because there is no proven e ective treatment for adenoviral conjunctivitis [20,21]; however, topical antibiotics are often prescribed to prevent bacterial superinfection. Corticosteroids should be avoided in treating most cases of pediatric adenoviral conjunctivitis and should only be administered under the care of an ophthalmologist. In fact, the prescription of ophthalmic steroids in general in the emergency department should be limited, because steroids can be devastating in the presence of herpetic infections, which must always be considered and e ectively ruled out.

Herpetic ocular infections outside of the neonatal period are typically from HSV-1 [6]. Herpetic keratitis with its classic dendritic pattern with fluorescein staining may be present, is most often unilateral, and is sometimes associated with vesicles in the distribution of the ophthalmic branch of the trigeminal nerve, involving the forehead, periorbital area, and tip of the nose [22]. More commonly, the clinical presentation of HSV conjunctivitis is nonspecific, although always painful, and very similar to other etiologies of conjunctivitis previously discussed. Treatment of HSV ocular infection, most often with a topical antiviral agent, should involve an ophthalmologist.