I read with interest the article by Wu et al1 concerning the measurement of visual function and the quality of life in patients with cytomegalovirus retinitis. In this article, the authors reported the results of a questionnaire designed to assess visual symptoms in affected patients, including perception of blurred vision, floaters, blind spots, seeing to the side, and bumping into things.
The authors noted that the question asking about blind spots or blurry spots was misinterpreted by patients as referring to floaters.
I believe that this observation deserves attention, as it is of clinical and theoretical interest. It reflects the fact that affected subjects usually do not perceive their visual field defects.2 Often, the presence of the scotoma is only recognized indirectly owing to the invisibility of the objects located within the field defect.
Scotomas are ignored as a result of a filling-in phenomenon, which consists in visual
Safran AB. Unperceived Visual Field Defects. Arch Ophthalmol. 1997;115(5):686-687. doi:10.1001/archopht.1997.01100150688033