In their recent case-control study, Ristau et al.
1 reported that a positive history of allergy had a protective effect on the development of age-related macular degeneration (AMD). Based on the proinflammatory nature of the AMD, they proposed that the inflammation may have conflicting roles as a protector and a promoter for AMD. Alternatively, they suggested that the susceptibility for allergy and the protection against AMD may share a common cause.
However, the story may be completely different. The apparent protective effect of allergy on AMD actually may be related to the effect of antiallergic drugs rather than the allergy itself. These drugs modulate immune response and are consumed frequently and chronically by allergic patients. It seems prudent that inflammatory cascades causing AMD somehow are blunted by antiallergic medications. If methodologically possible, I suggest that the authors evaluate possible association between different classes of antiallergic drugs with the development of AMD. In addition, since choroidal neovascularization and geographic atrophy have different pathophysiology,
2 any analysis should regard these presentations of late AMD as distinct entities.