Effect of dry eye on Scheimpflug imaging of the cornea and elevation data.

OBJECTIVE

To evaluate the effect of dry eye on Scheimpflug imaging of the cornea and elevation data.

DESIGN

Prospective observational study.

PARTICIPANTS

Scheimpflug images of 50 patients with dry eye who were being tested for eligibility for corneal refractive surgery were screened. Twelve eyes of 12 patients with abnormal Belin/Ambrosio enhanced ectasia display (BAD) anterior elevation difference were included in the study. The patients had no history of contact lens wear or any other sign of ectasia.

METHODS

Peak central corneal densitometry value, corneal volume, pachymetry at the thinnest point, and BAD anterior elevation difference value at the centre of the 9 mm zone were recorded before and after 4 weeks of dry eye treatment. Measurements were compared with the Wilcoxon signed rank test.

RESULTS

The mean corneal peak densitometry and volume were similar before and after therapy (p = 0.465 and p = 0.441, respectively). The mean anterior elevation difference value at the centre of the 9 mm zone before treatment (6.67 ± 1.72 µm) was significantly higher than the mean post-treatment value (4.00 ± 1.48 µm) (p = 0.002). The mean pachymetry at the thinnest location after treatment (548 ± 11.0) was significantly higher than the pretreatment value (538 ± 8.5) (p = 0.027).

CONCLUSIONS

BAD anterior elevation differences and pachymetric measurements may be affected by ocular surface or tear film abnormalities associated with dry eye disease. Repeated evaluations after treatment may reveal normal results.