Irregular astigmatism, left eye

This code signifies a refractive error in the left eye where the cornea or lens has an uneven curvature, causing light to focus at multiple points on the retina. Unlike regular astigmatism, the principal meridians are not 90 degrees apart, leading to more complex visual distortion.

Apply this code when documentation specifies irregular astigmatism affecting the patient's left eye. This diagnosis is often made following corneal topography or other advanced diagnostic imaging that reveals an asymmetrical corneal surface.

• Ensure laterality is clearly documented as "left eye" to support this specific code.
• Distinguish from regular astigmatism (H52.20x, H52.22x, H52.23x) where the principal meridians are perpendicular.
• Consider co-occurring conditions like keratoconus (H18.6x) or corneal scars (H17.x) which can cause irregular astigmatism.