Polarimetric Interferometry: New Technique for Assessment of Corneal Stromal Lamellae Orientation

Tuesday, April 21, 2015: 8:01 AM
Room 3 (San Diego Convention Center)
Alfonso Iovieno, MD, PhD
Eugenio Lipari, PhD
Yoav Nahum, MD
Massimo Busin, MD
Luigi Fontana, MD, PhD

To analyze corneal stromal lamellae orientation in normal subjects and in patients with various corneal conditions using a novel polarimetric interferometry device (Lumaxis, Phronema srl)

Observational study. 32 patients (62 eyes) healthy control subjects and 16 patients (25 eyes) with corneal affections/post-keratoplasty were included in the study. All patients were imaged using the Lumaxis interferometer and slit lamp photography. Corneal haze was graded semi-quantitatively on a scale from 0 to 4. Keratometry, central corneal pachymetry and corneal densitometry were also obtained with Scheimpflug corneal tomography (Pentacam, Oculus).

The Lumaxis interferometer produces an orthogonal cross-like image of stromal lamellae by illuminating the cornea in phase-light polarization angle. The cross-like image was observed in all healthy control subjects and in 13/16 patients (22/25 eyes) with total corneal neovascularization/scarring, central leukoma and failed DALK, respectively. Identification of the cross-like image was influenced by corneal haze grade and densitometry (p<0.05), but not by pachymetry or keratometry (p>0.05). There was no correspondence between the orientation of the corneal meridians and the position of the two arms of the cross-like image.

Corneal stromal lamellae orientation can be efficiently assessed and displayed as a cross-like image by the Lumaxis interferometer. Observation of the orientation pattern is consistent with previous X-rays and second harmonic generations studies on corneal stromal fibers orientation. Stromal lamellae orientation imaging could have potential implications in corneal diagnostics and surgery.