To the Editor The Commentary by Smith1 offered interpretations of the recent article by Gliem et al.2 Some comments on the corresponding Viewpoint might also be of additional interest. A mixture of retinaldehyde-adducts (bisretinoids) accumulates as retinal pigment epithelium lipofuscin and are the source of fundus autofluorescence. Smith1 wrote that the “role of lipofuscin may be protective” and cited the work of Molday3 and Palczewski.4 However, publications by these investigators describe bisretinoids as “toxic.”5 How does Smith reconcile that lipofuscin may be protective but bisretinoids, the source of fundus autofluorescence, are toxic?