1International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
2Ulverscroft Vision Research Group, Institute of Child Health and Great Ormond Street Hospital, London, United Kingdom
3Moorfields Eye Hospital, London, United Kingdom
Commercial Relationships: A. Taylor, None; S. Shah, None; J. Rahi, None; J. Sowden, None; I. Russell- Eggitt, None; N. Ragge, None; C. Gilbert, None.
Purpose:Typical or uveal coloboma specifically refers to a structural birth defect due to failure of optic fissure closure in embryogenesis. Very few population based studies have been conducted on these defects. This study provides a detailed clinical description of typical coloboma in the UK.
Methods:All UK born children (age <16 years), newly diagnosed with typical coloboma by an ophthalmologist between October 2006 and March 2008 were prospectively ascertained by active surveillance through the British Ophthalmological Surveillance Unit.
Results:99 children (51% male) were affected by typical colobomatous defects, 54 bilaterally. In 28 children (28.3%) colobomata were symmetrical, affecting the same anatomical locations in both eyes. Of 153 affected eyes, 66 had both anterior and posterior segment involvement, 66 had isolated posterior segment involvement and 21 had isolated anterior segment involvement. Chorioretinal colobomata were most commonly reported, present in 105 eyes, of which 39 involved the macula. Optic disc colobomata were present in 66 eyes. 37 children had associated anophthalmos (in the other eye) or microphthalmos (in the same or other eye). Bilateral visual impairment was reported in 41% of children. Systemic abnormalities were found in 60% of children and in 13 CHARGE syndrome was diagnosed or suspected . The median age at diagnosis was 2.9 months (IQR 0.7, 6.4). Aetiology was reported as unknown or suspected genetic in 62% and 35% of children respectively.
Conclusions:To our knowledge, this study represents the largest series of typical coloboma, confirmed by ophthalmologists, to date. Almost half of affected eyes had only posterior segment involvement, highlighting the importance of dilated fundal examination for accurate diagnosis of these defects which may not be visually obvious. As associated systemic defects and bilateral visual morbidity were found to be common in these children an early integrated approach to management is advised.
Keywords: clinical (human) or epidemiologic studies: prevalence/incidence choroid iris
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