Abstract
Purpose: :
To evaluate outcomes of Intacs surgery using the mechanical spreader versus the Intralase laser for channel creation in keratoconus and post-LASIK ectasia eyes.
Methods: :
Retrospective review identified 20 eyes that underwent Intacs surgery with the mechanical spreader and 24 eyes in which the Intralase femtosecond laser was used. Pre- and postoperative (approximately 1 and 6 months) uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), mean refractive spherical equivalent (MRSE), refractive cylinder and topography (EyeSys) were compared between the two groups.
Results: :
For mechanical eyes, mean UCVA was 20/304 preoperatively and improved to 20/166 and 20/138 at 1 (59.8 days) and at 6 months (262.7 days) respectively. For Intralase eyes, mean UCVA improved from 20/285 to 20/79 at 1 month (43.5 days) and was 20/87 at 6 months (120.3 days). At 6 months, the mechanical group showed an improvement of 2.29 lines of vision versus 3.05 lines for the Intralase group.Mean BCVA for mechanical eyes was 20/37 preoperatively and remained relatively unchanged at the 6 month visit (20/38). In Intralase eyes, mean BCVA was 20/34 preoperatively and improved to 20/27 at 6 months postoperatively.For mechanical eyes, mean preoperative MRSE was -6.26D (SD 3.81; range -1.125D to -14.75D) and for Intralase eyes was -4.73D (SD 4.2; range 0 to -16D). Mean MRSE improved by 1.88D (less myopia) (ranging from 14.75D reduction to 6.88D increase in myopia) in the mechanical group and by 1.34D (less myopia) (ranging from 12.5D reduction to 4.63D increase in myopia) in the Intralase group.Mean preoperative refractive cylinder was 5.25D (SD 3.50; range 1.57 to 13.39) and 4.28D (SD 3.02, range 0.16 to 11.91) for mechanical and Intralase eyes respectively. The mean change in cylinder in mechanical eyes was a decrease of 0.8D and a reduction of 0.58D in the Intralase eyes at the 6 month postoperative visit.Mean preoperative average topographic corneal power (EyeSys) was 48.87D (SD 6.59; range 41.44 to 66.60) in the mechanical group and 47.69D (SD 5.43; range 41.85 to 62.35) in the Intralase group. At 6 months postoperatively, the mean change in average corneal power was 2.33D flatter for mechanical eyes and 1.81D flatter for Intralase eyes.
Conclusions: :
Both mechanical and Intralase groups show improvements following surgery. The improvement in UCVA and BCVA appears to favor the Intralase treated groups, whereas refractive and topographic changes suggest an advantage using the mechanical spreader.
Keywords: keratoconus • cornea: clinical science • refractive surgery: other technologies