SIA Calculator

sia calculator test mobile image

Comprehensive Overview of SIA Calculator

The Surgically Induced Astigmatism (SIA) Calculator is a specialized tool designed to help ophthalmic surgeons assess the impact of surgical procedures—such as cataract surgery—on corneal astigmatism. By inputting essential data regarding the surgical procedure and pre- and post-operative keratometry, this calculator provides a precise measurement of surgically induced astigmatism (SIA), which helps surgeons plan for optimal refractive outcomes.

Patient Information

Eye: OD (Right Eye) or OS (Left Eye)

Incision Details

Location of Incision: Clock-hour or degrees (e.g., 180°)

Type of Incision: Clear Corneal (CC), Near Clear (NC), or Scleral

Incision Size (mm): (e.g., 2.2 mm, 2.75 mm)

Pre-operative Keratometry

K1 (Steep Axis): Value (D), Axis (°)

K2 (Flat Axis): Value (D), Axis (°)

Post-operative Keratometry

K1 (Steep Axis): Value (D), Axis (°)

K2 (Flat Axis): Value (D), Axis (°)

Results

Once the data is entered, the tool calculates the following:

  • SIA Magnitude (D): The total degree of astigmatic change caused by the surgical procedure.
  • SIA Axis (°): The direction of the astigmatic shift post-surgery.
  • Graphical Display (Optional): A vector diagram showing the relationship between the pre-op and post-op astigmatism changes, providing a visual representation of how the surgery has influenced the corneal shape.

This SIA Calculator assists in predicting refractive outcomes, aiding in better planning for future surgeries and ensuring optimal post-operative vision. By calculating the vector magnitude and axis of the induced astigmatism, surgeons can make informed decisions on how to manage residual astigmatism and correct any unexpected refractive errors.