The LASIK Residual Stromal Bed Calculator is a valuable tool used by ophthalmologists and surgeons to determine the thickness of the remaining corneal tissue after LASIK surgery. The RSB is a critical factor in the safety and success of the procedure. To understand its significance, let’s break down the formula:
Formula of LASIK Residual Stromal Bed Calculator
Residual Stromal Bed (RSB) = Initial Central Corneal Thickness (CCT) – (Flap Thickness + Laser Ablation Depth)
Here’s what each component of the formula represents:
Initial Central Corneal Thickness (CCT): This is the central thickness of the cornea before the LASIK procedure. It is typically measured in micrometers (µm). The initial CCT provides a baseline measurement for the calculation of RSB.
Flap Thickness: During LASIK surgery, a thin layer of the cornea’s outer tissue, known as the “flap,” is created. The flap’s thickness can vary depending on the specific LASIK technique and the surgeon’s preferences, but it typically falls within the range of 100 to 160 µm. Please note that we lift and then reposition the flap after the laser ablation, which is important.
Laser Ablation Depth: This component represents the amount of corneal tissue removed by the excimer laser during the LASIK procedure. The patient’s refractive error (i.e., how nearsighted, farsighted, or astigmatic they are) determines the laser ablation depth, which is measured in micrometers (µm). The LASIK surgeon calculates this depth based on pre-operative measurements and calculations.
To ensure the safety and success of the LASIK procedure, experts generally recommend maintaining a minimum residual stromal bed thickness of approximately 250-300 µm.
LASIK RSB Calculator – General Terms
We have provided a table of general terms commonly searched for, which can be helpful for you when using the LASIK Residual Stromal Bed Calculator, for your convenience.
| Term | Definition |
|---|---|
| LASIK | Laser-Assisted In Situ Keratomileusis, a vision correction surgery. |
| Cornea | The transparent front part of the eye that covers the iris and pupil. |
| Excimer Laser | A type of laser used for refractive eye surgeries like LASIK. |
| Refractive Error | A vision problem that occurs when the eye cannot focus light properly. |
| Micrometers (µm) | A unit of measurement equal to one millionth of a meter. |
Example of LASIK Residual Stromal Bed Calculator
Let’s illustrate how the LASIK Residual Stromal Bed Calculator works with a simple example:
Suppose a patient’s Initial Central Corneal Thickness (CCT) is 540 µm, the Flap Thickness is 120 µm, and the Laser Ablation Depth is 90 µm. To calculate the Residual Stromal Bed (RSB):
RSB = 540 µm – (120 µm + 90 µm) = 540 µm – 210 µm = 330 µm
Most Common FAQs
The RSB represents the thickness of the remaining corneal tissue after LASIK surgery. It is a critical factor for the safety and success of the procedure. A sufficient RSB ensures that the cornea retains its structural integrity.
Having an RSB thickness within this range is generally considered safe for LASIK surgery. It provides a buffer of corneal tissue to maintain the eye’s stability and structure.
Ophthalmologists and LASIK surgeons use the calculator to determine the RSB for each patient based on their individual corneal measurements. This helps in customizing the LASIK procedure for the best possible outcomes.