Quantitative assessment of corneal astigmatic surgery: expanding the polar values concept

Area of Science:

• Ophthalmology
• Corneal Surgery
• Optics

Background:

• Astigmatic corneal surgery aims to correct refractive errors by altering corneal curvature.
• Quantifying surgical outcomes is crucial for evaluating effectiveness and patient results.

Purpose of the Study:

• To introduce and define the astigmatic polar value (AKP) for quantifying astigmatic corneal surgery outcomes.
• To provide surgeons with a tool to immediately assess surgical correction levels.

Main Methods:

• Defining the with-the-power (WTP) and against-the-power (ATP) components of postoperative cylinder.
• Calculating the astigmatic polar value (AKP) using the formula: AKP = M x (sin2[(b + 90)-a] - cos2[(b + 90)-a]).

Main Results:

• The astigmatic polar value directly indicates whether astigmatic corneal surgery resulted in undercorrection, overcorrection, or perfect correction.
• The WTP and ATP components represent the dioptric values projected onto the preoperatively steeper and flatter meridians, respectively.

Conclusions:

• The astigmatic polar value offers a straightforward method for evaluating the success of astigmatic corneal surgery.
• This quantitative measure aids in surgical planning and outcome assessment.