The author presents four cases of transient visual loss (TVL) in young females (age range at presentation 14-22 years) with crowded optic discs. Patient demographics, investigations, medical and social histories are provided for all patients. A review of evidence for blood flow autoregulatory dysfunction in crowded optic discs in combination with reduced ocular perfusion is also presented. Patients 1-3 experienced bilateral and simultaneous TVL. Patient 4 had asymmetrical cup-to-disc ratios and a more crowded optic disc in the left eye and experienced monocular TVL in the left eye only. The author concludes that crowded optic discs with dysfunctional autoregulation in combination with low normal BPs could be considered in younger female patients as a differential diagnosis for both binocular and monocular transient visual loss. The development of future technologies is required to allow improved quantitative assessment of optic nerve head blood flow to provide further evidence for this hypothesis.