Seeing the Halo

Researchers evaluate a novel optical phenomenon that could expand the clinical value of slit-lamp examination in keratoconus

April 27, 2026
3 min

The Ophthalmologist

Objective:

To investigate the Halo Sign as a potential diagnostic indicator in advanced keratoconus.

Approach:

Key Findings:

The Halo Sign appears as an annular light projection on the iris in advanced keratoconus.
Halo-positive eyes exhibited poorer visual and structural parameters compared to halo-negative eyes.
The morphology of the halo varied significantly, indicating different levels of corneal distortion.

Interpretation:

The Halo Sign may serve as a marker of advanced structural deformation in keratoconus, reflecting optical irregularities rather than early disease indicators.

Limitations:

The study was limited to a small sample size of 22 eyes.
Findings are preliminary and require further validation in larger cohorts.

Conclusion:

The Halo Sign could enhance clinical evaluation of keratoconus, particularly in settings lacking advanced imaging technology, but should not replace comprehensive diagnostic approaches.