Relaxing incisions. Corneal topography

Area of Science:

• Ophthalmology
• Corneal Surgery
• Refractive Error Correction

Background:

• Corneal astigmatism is a common refractive error.
• Corneal relaxing incisions are used to reduce astigmatism.
• Understanding the topographic changes induced by these incisions is crucial for surgical planning.

Purpose of the Study:

• To investigate the corneal topography changes after circumferential corneal relaxing incisions.
• To quantify the astigmatic shift induced by varying numbers and placements of incisions.

Main Methods:

• Utilized the corneascope to analyze corneal topography.
• Studied eye bank corneas with circumferential corneal relaxing incisions.
• Measured flattening and steepening in perpendicular meridians.

Main Results:

• A consistent ratio of 2 diopters flattening to 1 diopter steepening was observed.
• Single unilateral incisions induced astigmatic changes from 0.58 D to 5.93 D.
• Symmetrical incisions induced greater astigmatic changes, ranging from 0.78 D to 13.97 D.
• Larger astigmatic shifts were associated with central corneal flattening.

Conclusions:

• Circumferential corneal relaxing incisions induce predictable topographic changes.
• The magnitude of astigmatic correction is dependent on incision length and symmetry.
• These findings aid in refining surgical techniques for astigmatism correction.