RT Journal A1 Kupfer C T1 USe of quality-of-life instruments in randomized clinical trials-reply JF Archives of Ophthalmology JO Archives of Ophthalmology YR 1997 FD April 1 VO 115 IS 4 SP 565 OP 565 DO 10.1001/archopht.1997.01100150566032 UL http://dx.doi.org/10.1001/archopht.1997.01100150566032 AB In reply  Dr Sommer correctly notes the 2 quality-of-life domains that must be addressed in such an instrument. The National Eye Institute-Visual Functioning Questionnaire (NEI-VFQ) does address both of the quality-of-life domains identified by Dr Sommer. With respect to customizing the instrument for a particular condition, this is not only expensive but fortunately unnecessary. In developing the NEI-VFQ, 25 focus groups were held in 5 sites around the country with patient impairment due to age-related cataract, glaucoma, diabetic retinopathy, age-related macular degeneration, and cytomegalovirus retinitis. Despite differences in the disease entity, the effect of these different causes of visual impairment on daily visual functioning and the quality of life was quite similar. Therefore, the NEI-VFQ was considered to be relevant to most visually impaired adults regardless of the underlying cause of the chronic visual problem. If it were necessary to customize the instrument, as for example to assess various forms