Later he became an assistant to Jannik Petersen Bjerrum (1851-1920), with whom he performed important studies in campimetry.
In 1910 he earned his medical doctorate, and in 1931 became a professor of ophthalmology at the university.
He also performed investigations involving the primary visual centres of the midbrain.
His name is lent to the eponymous "Rønne nasal step", defined as a nasal visual field defect that is considered a pathognomonic sign of glaucoma.
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