From the Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
The authors have no financial or proprietary interest in the materials presented herein.
Address correspondence to Hassan A. Aziz, MD, Bascom Palmer Eye Institute, 900 NW 17th Street, Miami, FL 33136. E-mail: email@example.com
Down syndrome is the most common chromosomal aberration associated with developmental delay.1 It is associated with a high incidence of ocular abnormalities, including epicanthus (84%), hyperopia (59%), strabismus (36%), telecanthus (17%), nasolacrimal duct obstruction (22%), myopia (9%), nystagmus (6%), and blepharoconjunctivitis (4%).2
Congenital bilateral macular coloboma is not a consequence of anomalous closure of the fetal fissure.3 Rather, it is thought to result from incomplete differentiation of the arcuate bundles along the horizontal raphe during development and appears as atrophic lesions with well-circumscribed borders,4 which result in a non-progressive decrease in visual acuity.
In this unique case, intraoperative optical coherence tomography (OCT) assisted in the diagnosis of bilateral macular coloboma in a patient with Down syndrome.
A 3-year-old girl was referred to the Bascom Palmer Eye Institute with a macular lesion. The patient was the product of an uncomplicated pregnancy. She was delivered at term with a birth weight of 5 pounds. She had no reported family history of eye disease or maldevelopment. She was suspected to have Down syndrome on prenatal ultrasonography and trisomy 21 was confirmed with chromosomal analysis at birth.
Her ophthalmic examination revealed high myopia (−6.5 diopters) in both eyes. Typical down-slanting palpebral fissures were observed. The cornea was clear with patent lacrimal duct system. The eyes were orthophoric with full range of movement. No nystagmus was noted. Dilated funduscopy revealed bilateral, round, well-circumscribed macular lesions of approximately 2 disc diameters in the right eye and 1.5 disc diameters in the left eye (Fig. 1). An artery coursed over the lesion without interruption in both eyes. Electroretinography performed under sedation showed normal responses in both eyes. Intraoperative spectral-domain OCT (Bioptigen, Research Triangle Park, NC) revealed atrophy of the neurosensory retina and absence of retinal pigment epithelium and choroid (Fig. 2). Based on clinical examination and OCT imaging, the patient was diagnosed as having bilateral macular coloboma.
Figure 1. A-well-circumscribed, round lesion of approximately 2 disc diameters in the right eye and 1.5 disc diameters in the left eye are seen over the macula.
Figure 2. Optical coherence tomography of the right macular lesion showing atrophy of the neurosensory retina and the retinal pigment epithelium (RPE) and choroid are absent.
Differential diagnosis of macular lesions in the pediatric population includes macular coloboma, congenital toxoplasmosis, geographic lesion (eg, cone dystrophy), Leber congenital amaurosis, healed congenital cytomegalovirus maculitis, congenital varicella, North Carolina macular dystrophy, central choroidal dystrophy, and trauma. Macular coloboma and post-inflammatory scars seen in congenital toxoplasmosis are morphologically similar and should be further differentiated.
Ocular toxoplasmosis is routinely ruled-in based solely on positive serological testing. Active lesions are sometimes unable to stimulate a systemic elevation in antibody titers because of small antigen load.5 Thus, OCT imaging can help confirm a diagnosis of toxoplasmosis. Characteristic OCT findings in congenital toxoplasmosis are retinal thinning, retinal pigment epithelium hyperreflectivity, and excavation of varying severity.6,7
In macular coloboma, the typical changes on OCT imaging are crater-like depression with atrophic neurosensory retina, lack of retinal pigment epithelium, choroid in the lesion, and absence of scleral ectasia.8 In our patient, the typical changes both clinically and on OCT confirmed the diagnosis of macular coloboma.
Yamaguchi and Tamai9 and Hayasaka and Hayasaka10 described two patients with bilateral congenital bilateral macular coloboma who had Down syndrome. The documentation of similar findings in three separate patients is suggestive that macular coloboma may be a rare ophthalmic pathology associated with Down syndrome.
The diagnosis of macular coloboma can potentially be made solely on clinical grounds; however, OCT imaging is an objective way of confirming the diagnosis. In this particular case, a complete evaluation of the patient prompted an examination under anesthesia, but the future is directed toward the use of handheld OCT and this will preclude the need to take the children to the operating room. Moreover, the previously reported cases of bilateral macular coloboma in patients with Down syndrome only substantiate the relationship between these two disease entities.
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- Gallagher MJ, Yilmaz T, Cervantes-Castañeda RA, Foster CS. The characteristic features of optical coherence tomography in posterior uveitis. Br J Ophthalmol. 2007;91:1680–1685. doi:10.1136/bjo.2007.124099 [CrossRef]
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- Hayasaka Y, Hayasaka S. Bilateral congenital macular coloboma in a boy with Down syndrome. Eur J Ophthalmol. 2004;14:565–567.