Standards for analyzing astigmatic outcomes: Part I: astigmatism basics.

Area of Science:

• Ophthalmology
• Optometry
• Vision Science

Background:

• Corneal astigmatism is prevalent, affecting over 60% of individuals with more than 0.50 diopters.
• Measurements of corneal astigmatism vary significantly between devices due to technological differences and imaged corneal regions.
• Ocular surface integrity is paramount for precise corneal astigmatism assessment.

Purpose of the Study:

• To highlight the importance of ocular surface optimization for accurate astigmatism measurements.
• To emphasize the need for multiple measurements and addressing discrepancies.
• To underscore the role of posterior corneal astigmatism and lens tilt in refractive outcomes.

Main Methods:

• Review of current practices and challenges in measuring corneal astigmatism.
• Discussion on the impact of ocular surface condition on measurement accuracy.
• Consideration of posterior corneal astigmatism and lens tilt in surgical planning.

Main Results:

• Optimizing the ocular surface before cataract surgery enhances the accuracy of preoperative astigmatism measurements and subsequent refractive results.
• Obtaining 2-3 measurements is recommended, with repeat measurements after ocular surface optimization to resolve discrepancies.
• Posterior corneal astigmatism and lens tilt are significant factors influencing total astigmatism and refractive outcomes.

Conclusions:

• Accurate corneal astigmatism measurement is vital for successful refractive surgery outcomes.
• Ocular surface optimization and multiple, consistent measurements are key to reliable astigmatism assessment.
• Comprehensive evaluation including posterior cornea and lens tilt is necessary for optimal toric intraocular lens implantation.