Alain Saad, Damien Gatinel. Accessed Aug. 15, 2019. Critical variable. This calculation takes into account both your corneal map and specific corneal thickness. After inserting the refraction intended to treat, you will see the Tissue Consumption (TC) for the different Optical Zones (OZ). U.S. Food and Drug Administration. In such cases where the cornea is too thin, LASIK can do more harm than good. The cornea is marked to aid in postoperative flap alignment. The surgeon adds the expected flap thickness (FT) to the planned ablation depth (AD), and then divides the sum by the eyes central corneal thickness (CCT). The diagnostic criteria are a central corneal thickness (CCT) less than 500 mm, in addition to topographic asymmetry. But we know that the whole eye is a very complex, dynamic, and fluid biomechanical system, Dr. Waring said. One significant criticism of the Risk Score System is that any individual less than 22 years old is automatically classified as at least 'Moderate Risk', despite the low incidence of ectasia in this age group. The Optical Zone will depend on the pupil size and the type of laser. The reason that this procedure has become so popular is that it is a long-term solution that actually corrects corneal aberrations, rather than just compensating for them. WebFemtosecond lasers tend to create more precise and uniform flap thickness, and settings of 100-120 m are typically used. J Cataract Refract Surg 2005; 31:20352038. Corneal thickness, degree of myopia and RSB are related and RSB thickness is the most significant predictor of ectasia among them. LASIK evolved from a variety of techniques in refractive surgery. This is a particularly important requirement for a few reasons. The higher your prescription is, the more We wont be making flaps in the future. It does also appear to play a role in eyes with abnormal topography, Dr. Santhiago said. J Cataract Refract Surg 2009; 35:16041608. 2019; doi:10.1016/S0140-6736(18)33209-4. Corneal Stability following Hyperopic LASIK with The best LASIK surgeons in Los Angeles are selective when it comes to their patients. Steroid and antibiotic drops are used for 4 to 10 days after surgery. Refer a Patient (720) 524-1001. WebObjective. The microkeratome (or femtosecond laser) is used to create a hinged corneal flap. As compared to specific residual stromal bed or CCT values, PTA likely provides a more individualized measure of biomechanical alteration because it considers the relationship between thickness, tissue altered through ablation and flap creation, and ultimate residual stromal bed thickness.. Calculation Evaluates Post-LASIK Ectasia Risk Before surgery the excimer laser, suction ring, microkeratome and blade (or femtosecond laser settings), are checked by the technician and the surgeon. DipCompSci(Cantab); Tariq A. Lewis, MSci, ARCS, OMT; Marine Gobbe, MSTOptom, PhD; Johnny Moore, FRCOphth, PhD, MD; Tara Moore, BSc, PhD Long-term Visual and Refractive Outcomes After Post-LASIK ectasia is considered in patients who developed increasing myopia, with or without increasing astigmatism, loss of uncorrected visual acuity, often loss of best-corrected visual acuity, Am J Ophthalmol. In Using a programmed laser, your eye surgeon reshapes parts of your cornea. They really go hand in hand.