STRABISMUS

Most children with strabismus do not have an intraocular tumor. However, about 30% of patients with retinoblastoma present initially with either esotropia or exotropia, due to the tumor location in the macular area which disrupts the child’s fixation. It is important that a retinal examination using the indirect ophthalmoscope be performed on every child with strabismus to exclude an underlying tumor.

VISUAL IMPAIRMENT

An older child with an intraocular tumor may complain of visual impairment or may be found to have decreased vision on visual testing in school. This usually occurs from destruction of the central retina by the tumor or by the presence of vitreous hemorrhage, hyphema, or secondary cataract formation.

Diagnostic approaches

Although some atypical tumors can defy clinical diagnosis, most ophthalmic tumors in children can be accurately diagnosed by a competent ophthalmologist or ocular oncologist.

Eyelid and conjunctiva

Most eyelid and conjunctival tumors are recognized by their typical clinical features, and special diagnostic studies are of little additional help. Smaller suspicious tumors in these tissues can be removed by excisional biopsy and the diagnosis established histopathologically. Larger tumors where the resulting defect cannot be repaired primarily, are best diagnosed by incisional biopsy and definitive treatment is withheld until a definite diagnosis has been established.

Orbital tumors

Unlike tumors of the eyelid and conjunctiva, orbital tumors cannot be directly visualized. Therefore, they often attain a relatively large size before becoming clinically evident. They generally present with proptosis or displacement of the eye. Pain, diplopia, and conjunctiva edema may also be early clinical features of an orbital tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) have revolutionized the diagnosis and treatment of orbital tumors.8 It is important to understand that CT in children could be associated with future cancer risk.9

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Intraocular tumors

Lesions of the iris can often be recognized with external ocular examination or slit-lamp biomicroscopy. Tumors of the retina and choroid can be visualized with ophthalmoscopy, which often reveals typical features depending on the type of tumor. Many small tumors are difficult to visualize and may only be detected by an experienced ophthalmologist using binocular indirect ophthalmoscopy. Ancillary studies such as fundus photography, autofluorescence, fluorescein angiography, indocyanine green angiography, ocular ultrasonography, and occasionally CT or MRI are of supplemental value in establishing the diagnosis. Optical coherence tomography (OCT) is a newer fundus scanning method using a rapid, noncontact technique with color-coded images in about 5 minutes. Children comfortably tolerate this technique.10 OCT can provide in vivo, highresolution information on the retina to the 10 µm level. Fine-needle aspiration biopsy (FNAB) has recently been employed in selected intraocular tumors of children.11 Such procedures in children often require general anesthesia.