Purpose: Evaluation of long-term functional and structural outcomes in patients with primary congenital glaucoma (PCG) based on visual acuity (VA), visual field (VF) using standard automated perimetry, and peripapillary retinal nerve fibre layer thickness (pRNFL). Methods: We retrospectively reviewed medical records of all patients diagnosed with PCG in Denmark from 1977 to 2016. Severe vision loss was defined as VA <6/60 and/or VF >20 decibels (dB). Prognostic factors were evaluated in a correlation matrix. Results: The median age of the 94 patients (153 PCG eyes) was 12 years (IQR 9–16). In PCG eyes 62% had VA ≥6/18 but 22% had <6/60. VA in the better seeing eye was ≥6/18 in 90% and <6/60 in 5%. VF was measured in 59 PCG eyes and the median mean defect was 5.1 dB (IQR 2.1–9.6) with 52% better than 6 dB and 9% worse than 20 dB. Generalized pRNFL was reduced below the age-expected 1st percentile in 29% of the 58 PCG eyes where pRNFL was measured. Poor VA, poor VF and reduced pRNFL were all correlated (p = 0.0001). More surgeries (p < 0.0001) and longer diagnostic delay (p = 0.004) were associated with poorer vision and to a lesser degree with poor VF pRNFL. Conclusion: In Denmark, most patients with bilateral PCG retain VA ≥6/18 in the better seeing eye. Poor VA was associated with poor VF. Longer diagnostic delay and more surgeries were associated with a poorer prognosis.