This 24 year-old man was referred by his optician because of this left optic disc appearance. The right optic disc was normal. His visual acuity was normal in both eyes.

a. What is the diagnosis?
 

Optic disc coloboma with involvement of the inferior choroid and retina.

It is caused by the failure of complete closure of the proximal end of the embryonic fissure. It is characterized by a white excavation in the disc which is decentered inferiorly. The inferior rim is usually thin or absent whereas the superior rim is relatively normal.


 

b. How does this condition differ from morning glory disc?
 

Optic disc coloboma	Morning glory disc
White excavation within the disc	Optic disc is located within the excavation
Central empty space	Fibrous tuft within the disc
No significant peripapillary pigmentation	Prominent peripapillary pigmentary changes
Retinal vasculature is usually normal	Abnormal retinal vasculature
May be unilateral or bilateral	Typically unilateral

c. What systemic conditions may be associated with this appearance?
 
Although often isolated, the following conditions have been associated with optic disc coloboma:
• basal encephalocele
• Aicardi's syndrome
• CHARGE association (Coloboma, Heart defects, Atresia choanae, Retarded growth and development, Genital hypoplasia, Ear anomaly and deafness)
• Goltz's focal dermal hypoplasia
• Meckel's syndrome
• Warburg's syndrome
• chromosome abnormalities such as trisomy 13 or 4p-


d. What complication may decrease the vision of this patient?
 

Central serous retinopathy is increased in patient with optic disc coloboma.