The LASIK industry & the FDA have conspired since LASIK's inception to purposely withhold information vital to the public in making a truly informed LASIK decision. With, The hope is to show you what the industry and FDA would not and did not even think of doing until LASIK casualties started speaking out, and yet, they still did NOTHING.
Spot size and quality of scanning laser correction of higher-order wavefront aberrations PDF Print E-mail
Monday, 18 September 2006 13:43

Cataract Refract Surg. 2002 Mar;28(3):407-16.


Huang D, Arif M.


Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.


PURPOSE: To investigate the effect of laser spot size on the outcome of aberration correction with scanning laser corneal ablation.


SETTING: Cleveland Clinic Foundation, Cleveland, Ohio, USA.


METHODS: Corrections of wavefront aberrations of Zernike modes from the second to eighth order were simulated. Gaussian and top-hat beams of 0.6 to 2.0 mm full-width-half-maximum diameters were modeled. The fractional correction and secondary aberration (distortion) were evaluated.


RESULTS: Using a distortion/correction ratio of less than 0.5 as a cutoff for adequate performance, a 2.0 mm or smaller beam was adequate for spherocylindrical correction (Zernike second order), a 1.0 mm or smaller beam was adequate for correction of up to fourth-order Zernike modes, and a 0.6 mm or smaller beam was adequate for correction of up to sixth-order Zernike modes.


CONCLUSIONS: Since ocular aberrations above the Zernike fourth order are relatively insignificant in normal eyes, current scanning lasers with a beam diameter of 1.0 mm or less are theoretically capable of eliminating most higher-order aberrations.