Content area
Full Text
The term leukokoria, popularized by A.B. Reese, is characterized by a white pupillary reflex produced by the reflection of light emanating from a light- colored or white intraocular mass or structure (Figure 1). It is the most common presenting sign of retinoblastoma, the most frequently occurring, lifethreatening intraocular malignancy of childhood. Unfortunately, many other pathologic entities may be clinically confused with retinoblastoma. Howard and Ellsworth1 published the results of a study of 500 consecutive patients, all of whom had leukokoria, who were referred for possible retinoblastoma. In 265 (53%) of these patients, other diagnoses were made.
The differential diagnosis of leukokoria in an infant or young child includes a spectrum of benign problems involving the structures of the eye. Recognition of defects of embryogenesis, vascular abnormalities, inflammation, infection, trauma, and tumors must be made in order to differentiate these conditions from retinoblastoma. Most have profound visual consequences and, therefore, require proper recognition and treatment (Table 1). Frequently, only a careful history and examination with a pen light or direct ophthalmoscope will be needed to arrive at the correct diagnosis. In other situations, ancillary diagnostic tests as well as the use of slit-lamp biomicroscopy and indirect ophthalmoscopy by experienced ophthalmologists will be required. This article reviews the various disease entities that may produce the clinical sign of leukokoria.
HIGH MYOPIA
In eyes with very high myopia, greater than 9 diopters either unilaterally or bilaterally, there may be marked thinning of the retina and choroid, or a large myopic crescent may be present around the temporal margin of the optic disc. These features, combined with the optical properties of the eye, may produce a white reflex when using a direct ophthalmoscope. Careful examination with the direct ophthalmoscope focused on the retina and optic disc, the use of indirect ophthalmoscopy, and measurement of the refractive error by retinoscopy will reveal the correct diagnosis.
CATARACTS
Careful examination of the pupillary space with a pen light, the plus lens of a direct ophthalmoscope, or by slit-lamp biomicroscopy will differentiate lens opacification from other causes of leukokoria (Figures 2A and B). Different morphologic types of cataracts occur, however, and posterior opacifications with a clear nucleus and anterior lens capsule may be difficult to differentiate from other causes of leukokoria, such as...