Nuclear lens opacities and visual acuity.

I am writing to you concerning the article entitled "Use of Photographic Techniques to Grade Nuclear Cataracts" by Sheila K. West, Grank Rosenthal, Henry S. Newland, and Hugh R. Taylor that appeared in the January 1988 issue of Investigative Ophthalmology and Visual Science. The study, performed by Dr. West and her coworkers, reports on the grading of nuclear lens opacities by clinical means, as well as with the use of a photo slit lamp, and a camera built on the "Scheimpflug" principle. In the section, Materials and Methods, as well as in Table 1, titled "Nuclear Opacity Grading Definitions," descriptions of varying degrees of opacification are described as being "consistent with" a visual acuity in specific ranges. However, no data are provided to indicate what were the actual visual acuities in the 24 subjects who were studied. The authors should be aware that cameras employing the Scheimpflug principle are now being marketed to ophthalmologists, some of whom are in turn using these instruments to document and justify cataract surgery in some of their patients. However, it is recognized that the appearance of lens opacities, particularly those associated with nuclear sclerosis, may be at variance with best corrected visual acuity. Most ophthalmologists have had patients whose nuclear opacities compare to "standard photograph 4" which appears in Figure 2 of the article by Dr. West and her colleagues, and who retain excellent visual acuity. Conversely, some patients with minimal nuclear changes, such as those illustrated in "standard photograph 1", may show significant degradation of visual acuity. Unless the authors of this report have data which support their assumption that nuclear opacities are consistent with given levels of visual acuity, they should clearly disavow this aspect of their study. Otherwise, they are likely to find themselves quoted by colleagues they never knew they had and wish they didn't. George W. Weinstein, MD Department of Ophthalmology West Virginia University Morgantown, West Virginia