Philadelphia, Bucks County, Montgomery County, Elkins Park, Phoenixeville, Conshohocken - Dr. James S. Lewis LASIK Specialist
SBK Thin Flap LASIK
Understanding the difference between Laser Vision Correction with a corneal flap (LASIK) and Laser Vision Correction without a corneal flap (Epi-LASIK)
All modern laser vision correction procedures use an excimer laser to reshape your cornea. All excimer lasers, regardless of their manufacturer, output 193 nanometer light for corneal ablation. The unique ability of the excimer laser to reshape corneal tissue is the breakthrough that started modern refractive surgery.
Laser Vision Correction can be divided into two main categories. One is surface corneal ablation and the other is below the corneal flap corneal ablation.
Laser Vision Correction without a corneal flap (surface ablation).
- Bladeless Epi-LASIK exposes the most superficial layer of your corneal stroma to excimer sculpting. Your reshaped cornea maintains maximal strength and structural integrity. The vast majority of your corneal anatomy remains untouched.
- Older surface ablation techniques like PRK (photorefractive keratoplasty), LASEK (laser assisted epithelial keratomileusis), and transepithelial ablation use less elegant methods to expose the superficial corneal stroma. Most of these methods have fallen out of favor.
Laser Vision Correction with a corneal flap (LASIK).
- Flap-based techniques include standard LASIK, custom LASIK, and so-called “All Laser LASIK”. Regardless of the technique, a corneal flap is created and less of your corneal structure is preserved. The Excimer laser is applied beneath the corneal flap.
- Femtosecond lasers like Intralase™ and Zeimer™ are indeed bladeless. However, instead of a scalpel they use a series of multiple microscopic laser explosions to cut a corneal flap. All of these methods, including “All Laser LASIK” are susceptible to flap complications. All flap-based techniques leave you with less corneal resistance to trauma.
The great advantage of LASIK over Epi-LASIK is speed of recovery, convenience, and comfort. Dr. Lewis's Philadelphia LASIK patients can almost always legally drive to their follow-up appointment the next day without glasses. LASIK patients can expect an immediate return of vision and full activities. Also, LASIK patients are extremely easy to enhance since no new corneal flap is needed.
Mechanical Thin Flap LASIK or m-SBK (Sub-Bowman's Keratomileusis) is the only kind of LASIK we perform. The corneal flap is made just beneath the surface which is approximately 100 microns down. Conventional LASIK can result in flap thickness between 130 and 220 microns or almost half the corneal thickness. Obviously, the more superficial the better for corneal strength and structure integrity. Even All Laser LASIK can not achieve flaps less than 115 microns in thickness consequently we feel m-SBK produces the safest, strongest, and most physiological LASIK possible.