Purpose: To categorize and describe the type of optic disc involvement and blood vessel patterns seen in patients with fundus coloboma.
Methods: This is a prospective study involving 67 eyes of 40 patients with choroidal coloboma. The evaluation included documentation of fundus details using fundus drawings or photographs, or both.
Results: Six types of disc involvement were identified: (1) normal disc outside fundus coloboma (27.8%); (2) disc outside the fundus coloboma and abnormal (10.4%); (3) disc outside the fundus coloboma and independently colobomatous (8.9%); (4) disc within the fundus coloboma and normal (5.0%); (5) disc within the fundus coloboma and colobomatous (44.3%); and (6) disc shape not identified but blood vessels seen emanating from the superior border of the large fundus coloboma (2.9%). Visual acuity was better in types I, II, and III compared with IV, V, and VI. Microphthalmos was more common with the more severe anomalies. High myopia was more common in the less severe anomalies.
Conclusion: Optic disc involvement in fundus coloboma is widely variable. Of fundus colobomas, 67.2% are associated with either a frankly colobomatous or an altered disc. Of the discs located outside fundus colobomas, 41% are also abnormal. Visual acuity was better in types I, II, and III.