Dr Raymond Stein of the Bochner Eye Institute wrote the following clinical update. We hope you find it of interest.
Many reports have demonstrated the superiority of Femtosecond laser created flaps over a microkeratome blade: increased flap thickness accuracy,1,2,3 greater consistency of flap thickness,4,5 the elimination of buttonhole flaps,1,6 decreased epithelial injury,4, 7, greater flap adhesion strength, 8 ,faster visual recovery and better uncorrected visual acuity,8,9 improved contrast sensitivity,10 better refractive astigmatic neutrality,5 decreased higher order aberrations,11 and decreased corneal insensitivity and tear function compromises.12,13
The laser flap has a uniform or planar thickness. A blade creates a meniscus flap which results in a thinner flap in the centre and thicker in the periphery. This can lead to one of the most dreaded LASIK complications of a button-hole. This can result in loss of best-corrected vision from irregular astigmatism or scar tissue. When we acquired a Femtosecond laser 4 years ago we thought initially we would offer both the Femtosecond and blade technologies. After doing our first cases we quickly sold our microkeratome. All prospective laser patients should be aware that the Femtosecond laser provides the most technologically advanced and safest procedure.
Why would some laser centres today offer inferior technology? The answer is very clear – cost. The purchase of a Femtosecond laser costs around $500,000, there is an annual maintenance fee of around $70,000, and a disposable cost (suction ring) of approximately $200 per eye. A microkeratome can be purchased for $25,000 or less, there are no annual maintenance fees, and the cost of a blade is around $50 for both eyes. So you can see from a cost point of view there are significant savings to a laser centre to offer inferior technology with a microkeratome.
Femtosecond technology continues to advance. At the Bochner Eye Institute we acquired the first IFS laser in Canada, which has a speed of 150 KHz. This is 2.5 times faster than the previous laser technology. This results in the suction ring being on the eye for less time resulting in a more comfortable experience for the patient. In addition the new technology can create a flap edge greater than 100 degrees. This leads to a more stable flap position like a man-hole cover, and a lower incidence of epithelial ingrowth.
At the Bochner Eye Institute we continue to treat a significant number of eye-care professionals from across Canada and the United States. We feel this is because eye doctors understand leading edge technology and trust our surgical techniques and abilities.
1.Binder PS. Flap dimensions created with the Intralase FS Laser. J Cataract Refract Surg. 2004;30:26-32.
2. Javaloy J, Vidal MT, Abdelrahman AM, Artola A, Alio JL. Confocal microscopy comparison of Intralase femtosecond laser and Moria M2 microkeratome in LASIK. J Cataract Refract Surg. 2007; 23:178-187.
3. Patel SV, Maguire LJ, McLaren W, Hodge DO, Bourne WM. Femtosecond laser versus mechanical microkeratome for LASIK: a randomized controlled study. Am J Ophthalmol. 2007;114:1482-1490.
4. Kezirian GM, Stonecipher KG. Comparison of the Intralase femtosecond laser and mechanical keratomes for laser in situ keratomileusis. J Cataract Refract Surg. 2004;30:804-811.
5. Talamo JH, Meltzer J, Gardner J. Reproducibility of flap thickness with Intralase FS and Moria LSK-1 and M2 microkeratomes. J Cataract Refract Surg. 2006;22:556-561.
6. Binder PS. One thousand consecutive IntraLase laser in situ keratomileusis flaps. J Cataract Refract Surg. 2006;32:962-969.
7. Duffey RJ. Thin flap laser in situ keratomileusis: flap dimensions with the Moria LSK-One manual microkeratome using the 100-micron head. J Cataract Refract Surg. 2005;31:1159-1162.
8. Knorz MC, Vossmerbaeumer U. Comparison of flap adhesion strength using the Amadeus microkeratome and the IntraLase IFS femtosecond laser in rabbits. J Refract Surg. 2008;24:875-878.
9. Durrie DS, Kezirian GM. Femtosecond laser versus mechanical keratome flaps in wavefront-guided laser in situ keratomileusis: a prospective contralateral eye study. J Cataract Refract Surg. 2005;31:120-126.
10. Tanna M, Schallhorn SC, Hettinger KA. Femtosecond laser versus mechanical microkeratome: a retrospective comparison of visual outcomes at 3 months. J Refract Surg. 2009;25:S668-S671.
11.Montes-Mico R, Rodriguez-Galietero A, Alio JL. Femtosecond laser versus mechanical keratome LASIK for myopia. Ophthalmology. 2007;114:62-68.
12. Tran DB, Sarayba MA, Bor Z, Garufis G, et al. Randomized prospective clinical study comparing induced aberrations with IntraLase and Hansatome flap creation in fellow eyes. J Cataract Refract Surg. 2005;31:97-105.
13. Lim T, Yang S, Kim MJ, Tchah H. Comparison of the IntraLase femtosecond laser and mechanical microkeratome for laser in situ keratomileusis. Am J Ophthalmol. 2006;141:833-839.
14. Barequet IS, Hirsh A, Levinger S. Effect of thin femtosecond LASIK flaps on corneal sensitivity and tear function. J Refract Surg. 2008;24:897-902.