Effectiveness of the Humphrey Vision Analyzer low vision slide on the partially sighted.

Subjective refractions were performed on a variety of low vision patients using the Humphrey Vision Analyzer (HVA) which incorporates a low vision slide. Twenty-one eyes were examined and results were compared with standardized trial frame refraction findings. The results indicate that the HVA is an effective alternative procedure for some low vision patients, although several factors, including design of the slide, patient alignment, and target illumination, need to be carefully considered if this technique is to replace the conventional low vision trial frame examination.