Flexure can help minimize residual astigmatism in patients with which corneal astigmatism?

Flexure can help minimize residual astigmatism in patients with which corneal astigmatism?

• A. WTR
• B. ATR
• C. Oblique
• D. No astigmatism

Answer: (A)

Flexure describes the small, eyelid‑induced reshaping of the cornea that happens with blinking and lid pressure. This effect tends to flatten the meridian that is steeper when a patient has astigmatism. For with-the-rule astigmatism, the vertical meridian is the steep one. When the eye blinks or the lids interact with the cornea, the vertical meridian gets a bit flatter, which reduces the difference between the two principal meridians. That means the residual astigmatism after correction is minimized more effectively in this pattern. If the corneal astigmatism is against-the-rule or oblique, the same eyelid-induced flattening doesn’t align with the steep meridian in a way that reliably reduces the residual cylinder, so the benefit isn’t as pronounced. And if there’s no astigmatism to begin with, flexure can’t further reduce what isn’t present.

Flexure describes the small, eyelid‑induced reshaping of the cornea that happens with blinking and lid pressure. This effect tends to flatten the meridian that is steeper when a patient has astigmatism. For with-the-rule astigmatism, the vertical meridian is the steep one. When the eye blinks or the lids interact with the cornea, the vertical meridian gets a bit flatter, which reduces the difference between the two principal meridians. That means the residual astigmatism after correction is minimized more effectively in this pattern.

If the corneal astigmatism is against-the-rule or oblique, the same eyelid-induced flattening doesn’t align with the steep meridian in a way that reliably reduces the residual cylinder, so the benefit isn’t as pronounced. And if there’s no astigmatism to begin with, flexure can’t further reduce what isn’t present.