Aim: Primary congenital glaucoma is the most prevalent type of primary paediatric glaucoma. The aim of the study was to estimate functional and morphological parameters in eyes with primary congenital glaucoma, with and without Haab's striae, after classic trabeculectomy in the long-term follow-up. Material and methods: 41 eyes of 27 children aged 7 days to 12 months at primary trabeculectomy with (group I) and without Haab's striae (group II) were reviewed. The best corrected visual acuity, intraocular pressure, central corneal thickness, axial biometry, corneal horizontal diameter, refraction, central endothelial cell density, cup-to-disc ratio, and perimetric mean deviation were analysed. Results: The mean follow-up was 11.4 years. The mean age of operated infants was 5.65 months (group I) and 4.41 months (group II). The mean intraocular pressure before trabeculectomy was significantly higher and endothelial cell density was significantly lower in group I than in group II. The mean myopic refractive error was significantly higher in group I than in group II. There was no difference in best corrected visual acuity, central corneal thickness, axial biometry, corneal horizontal diameter, and perimetric mean deviation between the two groups. Conclusions: The visual function in patients with primary congenital glaucoma after successful trabeculectomy performed in infancy is satisfactory, despite the presence of Haab's striae, impaired corneal structure and decreased endothelial cell density. High intraocular pressure before treatment is an important risk factor for the development of Haab's striae. Classic trabeculectomy is a good first-line surgical procedure in the treatment of primary congenital glaucoma with and without Haab's striae.