BACKGROUND To report an unusual case of bilateral optic disc coloboma associated with macular retinoschisis in the left eye. CASE SUMMARY A 37-year-old woman presented with complaints of blurred and distorted vision in her left eye for more than 1 year. Fundus examination demonstrated choroidal atrophy around the optic disc in both eyes, with a cup-to-disc ratio of 0.9. Serous retinal detachment in the macular area of the left eye. Left eye macular blood flow imaging optical coherence tomography (Angio-OCT) showed macular retinal serous cleavage. En-face OCT showed that the canal gully-like structure formed by the defect of the optic disc nerve fiber layer between the optic disc and macula, serous detachment area was connected with the enlarged optic disc coloboma through the canal gully-like structure, and the fluid leaked from the enlarged and thinned optic disc coloboma into the retinal layer of the macular area. Patients with optic disc abnormalities and macular degeneration must be monitored appropriately. During the follow-up period, the use of optic disc stereography and 3D-OCT, en-face, and Angio-OCT imaging can clarify the correlation between macular retinoschisis and optic disc coloboma. CONCLUSION Macular retinoschisis may be owing to the combined force of disc edge loss, enlarged optic disc coloboma, the canal gully-like structure formed by the defect of the nerve fiber layer around the optic disc, and the traction of the posterior vitreous cortex.