Original Article
Comparison of the anterior corneal asphericity after small incision lenticule extraction and femtosecond laser in situ keratomileusis
Xiaolian Su, Yan Wang, Wenjing Wu, Zhiqing Wu, Yanan Wu, Changjiang Yu
Published 2016-09-11
Cite as Chin J Ophthalmol, 2016, 52(9): 681-685. DOI: 10.3760/cma.j.issn.0412-4081.2016.09.009
Abstract
ObjectiveTo evaluate and compare the anterior corneal asphericity after small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK).
MethodsIn this case-control study, 45 subjects who underwent SMILE operation comprised the study group, and 33 subjects with FS-LASIK operation comprised the control group. The asphericity coefficient Q-value of the right eyes in both groups was measured at diameters of 6, 7, 8 and 9 mm, respectively, before surgery and at 1 day, 1 week, 1 month and 6 months following surgery. The correlation between the variation of Q-value and the central cutting depth was analyzed.
ResultsThe Q-value of anterior corneal surface was 0.85 ± 0.31, 0.80±0.28, 0.69±0.25 and 0.51±0.23 after SMILE, and 1.13±0.56, 1.01±0.47, 0.80±0.39 and 0.51±0.31 after FS-LASIK at 1 week. In both groups, the Q-value was significantly different before and after surgery(P< 0.05); there were interaction effects between the operation method and time; the difference between the two groups at 6-mm and 7-mm diameters was statistically significant(P<0.05). The variation of the Q-value before and after operation(ΔQ)showed significant difference(P6mm=0.004, P7mm=0.014)between the two groups at 6-mm and 7-mm diameters. The cap diameter of the SMILE group was smaller than that of the FS-LASIK group, but the cutting depth was larger. There was no correlation between ΔQ and the cap/disc diameter. It showed a linear relationship(P<0.05)between ΔQ and the central cutting depth at all examined diameters in the two groups, and the relation degree in the FS-LASIK group was superior to the SMILE group.
ConclusionsBoth SMILE and FS-LASIK operations can change the negative Q-value of the anterior corneal surface to the positive. The impact of SMILE on the asphericity is smaller than that of FS-LASIK. (Chin J Ophthalmol, 2016, 52: 681-685)
Key words:
Refractive surgical procedures; Corneal surgery, laser; Keratomileusis, laser in situ; Laser, femtosecond; Lasers, excimer; Corneal stroma; Visual acuity
Contributor Information
Xiaolian Su
Tianjin Eye Hospital, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Institute, Clinical College of Ophthalmology, Tianjin Medical University, Tianjin 300020, China
Yan Wang
Wenjing Wu
Zhiqing Wu
Yanan Wu
Changjiang Yu