If you’re looking for an objective way to evaluate both the severity of dry eye and the efficacy of artificial tears, a new study may help to point you in the right direction. Researchers evaluated corneal surface regularity and the effect of artificial tears on this regularity in dry eye. They studied 64 eyes of 33 normal subjects and 42 eyes of 22 patients who had aqueous tear deficiency. Corneal topography was used to evaluate corneal surface regularity and potential visual acuity (PVA) in dry eye patients before and after artificial tears were instilled. Normal subjects were evaluated with corneal topography. Then the topographic maps were classified and studied. Compared with normal subjects, dry-eye patients had significantly elevated surface regularity index (SRI) and surface asymmetry index (SAI), and significantly reduced PVA. Dry eyes also showed more astigmatism. In dry eyes, SRI and SAI were positively correlated with corneal fluorescein staining scores. The mean PVA was about the same as the mean actual corrected visual acuity. After artificial tears were instilled, SRI, SAI and mean astigmatism all decreased in dry eyes, and the PVA improved. The scientists believe that dry-eye patients have irregular corneal surfaces that contribute to their visual difficulties. SRI and SAI can be used as objective indices for dry eye, as well as for evaluating its degree and how helpful artificial tears are in treating it. The artificial tears, they say, also have the secondary benefit of smoothing the corneal surface and reducing the astigmatism.