Clinical distinction between nasal optic disc hypoplasia (NOH) and glaucoma with NOH-like temporal visual field defects

PURPOSE To report on the clinically important differences between nasal optic hypoplasia (NOH) and glaucoma with NOH-like temporal visual field defect (VFD). METHOD Five NOH (four bilateral and one unilateral) patients, three unilateral NOH patients with glaucoma, and two glaucoma patients with NOH-like temporal VFD were clinically characterized. Superior segmental optic nerve hypoplasia was also associated with glaucoma in one eye of a bilateral NOH case and the NOH eye of a unilateral NOH patient. Ocular manifestations including refractive errors, size, and appearances of the optic discs, retinal nerve fiber thickness (NFLT) ascertained by optical coherence tomography (OCT), and VFD were examined. RESULTS Ophthalmic examinations revealing NOH showed high myopia at more than -5.0D, a small disc with nasal double-ring appearance, significantly decreased NFLT by OCT, and retinal nerve fiber layer defect in the corresponding nasal sector. Stationary temporal VFD varied from a slight depression of the peripheral isopters to wide sector defects. In contrast, two glaucoma patients with NOH-like temporal VFD showed several different clinical features, including mild myopia less than -5D, a normal size with glaucomatous disc cupping; a slight decrease in nasal NFLT and progression of temporal and other glaucomatous VFD. CONCLUSION Careful evaluation of optic disc appearance and measurement of NFLT using OCT may help to distinguish between NOH and glaucoma with NOH-like temporal VFD.