Critical analysis of visual function evaluating techniques in newborn babies.

The most widely-used techniques for testing visual function in babies are reviewed. Advantages and limitations of optokinetic nystagmus testing, visual evoked responses and preferential looking techniques are considered. The theoretical basis and the clinical applicability of those techniques are outlined. Other simple methods are considered as well, which allow practicing ophthalmologists to assess the presence or absence of vision in babies. The importance of early diagnosis for prevention and treatment of visual deficits in babies is stressed.