Purpose: To study the effect of microkeratome suction on ocular structures dur ing LASIK. Design: Observational, prospective case series. Participants: Twenty -one eyes of 11 patients with myopia or astigmatic myopia ...Purpose: To study the effect of microkeratome suction on ocular structures dur ing LASIK. Design: Observational, prospective case series. Participants: Twenty -one eyes of 11 patients with myopia or astigmatic myopia (8 females, 3 males) were included. The mean patient age was 36.3 years (median, 37 years; range, 24 -48 years), and the mean spherical equivalent was-5.03 diopters(D) (median,-4 .63 D; range,-2.38 to -8.38 D). Methods: We performed preoperative and intraop erative A-scan ultrasonography during applicat ion of suction using the Hansatome microkeratome (Bausch &Lomb Surgical,Munich, Germany) to create corneal flaps during LASIK. We also performed preoperative a nd postoperative B-scan ultrasonography of the posterior ocular segment with sp ecial attention to the presence and size of posterior vitreous detachment (PVD). Main Outcome Measures: We measured changes in the axial length, anterior chambe r depth, lens thickness, and vitreous distance (distance from the posterior lens capsule to the posterior pole) during application of the microkeratome suction ring and recorded new occurrences of or increases in the size of the PVD after s urgery. Results: The lens thickness decreased (mean change,-0.20 mm; P=0.001; 9 5%confidence interval [CI],-0.11 to-0.30) in 18 eyes during application of th e suction ring. The vitreous distance increased (mean change, 0.20 mm; P=0.004; 95%CI, 0.08-0.32) in 16 eyes. No statistically significant changes were found in the anterior chamber depth (P=0.75) or axial length (P=0.51). After surgery, 3 of 14 eyes (21.4%) experienced PVD that did not have echographic signs of PVD before surgery. Of 7 eyes with preoperative PVD, the PVD enlarged in 1 eye (14. 3%). Conclusions: During application of microkeratome suction, the lens thickne ss decreases, whereas the vitreous distance increases, suggesting anterior tract ion on the posterior segment. The relationship between the observed PVD and LASI K merits further investigation.展开更多
To assess safety, efficacy, predictability, stability, and change in aberratio ns after wavefront-guided LASIK for myopia and myopic astigmatism. Prospective, nonrandomized, self-controlled trial. Wavefront-guided LAS...To assess safety, efficacy, predictability, stability, and change in aberratio ns after wavefront-guided LASIK for myopia and myopic astigmatism. Prospective, nonrandomized, self-controlled trial. Wavefront-guided LASIK was performed in 97 eyes in a 1-year trial. Treated eyes had a mean subjective manifest spheric al equivalent (SE) of -5.22±2.07 diopters (D), with a range of -0.25 to -9.0 0 D of myopia and 0 to -3.25 D of astigmatism. After a microkeratome cut, a wav efront-based excimer ablation (Zyoptix 3.1) was performed. The full treatment t o achieve emmetropia of an early nomogram provided by the system manufacturer wa s used in all procedures. Safety, efficacy, predictability, and stability were e valuated at 1, 3, and 12 months postoperatively. Wavefront changes of higher ord er aberrations (HOAs) at 1 year were determined for pupil sizes of 3.5 and 6 mm. At 1 year postoperatively, uncorrected visual acuity (VA) was 20/20 or better i n 83%of the eyes, and 20/40 or better in 98%. The mean subjective manifest SE at 1 year was -0.25±0.43 D; it was within 0.50 D in 77%and within 1.0 D in 95 %. No eye lost < 2 lines of best spectacle corrected VA (BSCVA) at 1 year post operatively; 40 eyes gained 1 line of BSCVA, and 5 eyes gained 2 lines. The tota l HOA root meansquare (RMS) increased on average by a factor of 1.23±0.57 with a 3.5-mm pupil; for the 6 mm pupil, the increase factor was 1.52±0.36. No chan ge or reduction in the total HOA RMS was observed in 45.5%of the eyes for a 3.5 -mm pupil and in 20.6%for a 6-mm pupil. There was a significant increase of p rimary spherical aberration (Z 4,0) by a factor of 4.11±10.17 for 3.5-mm pupil s and 4.31±6.76 for 6-mm pupils. Wavefront-guided LASIK using Zyoptix 3.1 is an effective and safe procedure for the treatment of myopia and myopic astigmati sm. Although in close to half of the eyes HOAs could be reduced, there was still undercorrection and induction of HOAs with the algorithm employed.展开更多
Background: Vitreoretinal complications are rare in laser in situ keratomileusis (LASIK). Increase in intraocular pressure caused by intraoperative suction with subsequent deforming of the ocular globe and excimer las...Background: Vitreoretinal complications are rare in laser in situ keratomileusis (LASIK). Increase in intraocular pressure caused by intraoperative suction with subsequent deforming of the ocular globe and excimer laser shock during the ablation have been discussed as possible causes. The purpose of this study was to determine the effect of LASIK on the vitreous body. Patients and methods: In a prospective study we performed ocular ultrasonography (B scan) immediately before and 1 week after LASIK procedure in 103 myopic or myopic astigmatic eyes (53 patients, mean age 36.3 years, 32 women, 21 men). In particular, the prevalence, localization, and extent of posterior vitreous detachment (PVD) were determined. Results: The mean spherical equivalent was- 4.85 D (range- 1.25 to- 8.38) and the mean anteroposterior ocular globe length was 25.13 mm (range 23.31- 27.65). Ninety-five eyes (92.2% ) had no PVD preoperatively. Nine eyes out of this group (seven patients, 9.5% ) developed incomplete PVD as assessed 1 week postoperatively. Eight eyes (7.8% ) had a partial PVD preoperatively and in only one eye was an extension of vitreous detachment observed after the surgery. None of the preoperatively measured parameters could predict the occurrence of PVD by LASIK. Conclusions: LASIK may in rare cases lead to new occurrence of PVD or extension of a previously existing partial PVD.展开更多
文摘Purpose: To study the effect of microkeratome suction on ocular structures dur ing LASIK. Design: Observational, prospective case series. Participants: Twenty -one eyes of 11 patients with myopia or astigmatic myopia (8 females, 3 males) were included. The mean patient age was 36.3 years (median, 37 years; range, 24 -48 years), and the mean spherical equivalent was-5.03 diopters(D) (median,-4 .63 D; range,-2.38 to -8.38 D). Methods: We performed preoperative and intraop erative A-scan ultrasonography during applicat ion of suction using the Hansatome microkeratome (Bausch &Lomb Surgical,Munich, Germany) to create corneal flaps during LASIK. We also performed preoperative a nd postoperative B-scan ultrasonography of the posterior ocular segment with sp ecial attention to the presence and size of posterior vitreous detachment (PVD). Main Outcome Measures: We measured changes in the axial length, anterior chambe r depth, lens thickness, and vitreous distance (distance from the posterior lens capsule to the posterior pole) during application of the microkeratome suction ring and recorded new occurrences of or increases in the size of the PVD after s urgery. Results: The lens thickness decreased (mean change,-0.20 mm; P=0.001; 9 5%confidence interval [CI],-0.11 to-0.30) in 18 eyes during application of th e suction ring. The vitreous distance increased (mean change, 0.20 mm; P=0.004; 95%CI, 0.08-0.32) in 16 eyes. No statistically significant changes were found in the anterior chamber depth (P=0.75) or axial length (P=0.51). After surgery, 3 of 14 eyes (21.4%) experienced PVD that did not have echographic signs of PVD before surgery. Of 7 eyes with preoperative PVD, the PVD enlarged in 1 eye (14. 3%). Conclusions: During application of microkeratome suction, the lens thickne ss decreases, whereas the vitreous distance increases, suggesting anterior tract ion on the posterior segment. The relationship between the observed PVD and LASI K merits further investigation.
文摘To assess safety, efficacy, predictability, stability, and change in aberratio ns after wavefront-guided LASIK for myopia and myopic astigmatism. Prospective, nonrandomized, self-controlled trial. Wavefront-guided LASIK was performed in 97 eyes in a 1-year trial. Treated eyes had a mean subjective manifest spheric al equivalent (SE) of -5.22±2.07 diopters (D), with a range of -0.25 to -9.0 0 D of myopia and 0 to -3.25 D of astigmatism. After a microkeratome cut, a wav efront-based excimer ablation (Zyoptix 3.1) was performed. The full treatment t o achieve emmetropia of an early nomogram provided by the system manufacturer wa s used in all procedures. Safety, efficacy, predictability, and stability were e valuated at 1, 3, and 12 months postoperatively. Wavefront changes of higher ord er aberrations (HOAs) at 1 year were determined for pupil sizes of 3.5 and 6 mm. At 1 year postoperatively, uncorrected visual acuity (VA) was 20/20 or better i n 83%of the eyes, and 20/40 or better in 98%. The mean subjective manifest SE at 1 year was -0.25±0.43 D; it was within 0.50 D in 77%and within 1.0 D in 95 %. No eye lost < 2 lines of best spectacle corrected VA (BSCVA) at 1 year post operatively; 40 eyes gained 1 line of BSCVA, and 5 eyes gained 2 lines. The tota l HOA root meansquare (RMS) increased on average by a factor of 1.23±0.57 with a 3.5-mm pupil; for the 6 mm pupil, the increase factor was 1.52±0.36. No chan ge or reduction in the total HOA RMS was observed in 45.5%of the eyes for a 3.5 -mm pupil and in 20.6%for a 6-mm pupil. There was a significant increase of p rimary spherical aberration (Z 4,0) by a factor of 4.11±10.17 for 3.5-mm pupil s and 4.31±6.76 for 6-mm pupils. Wavefront-guided LASIK using Zyoptix 3.1 is an effective and safe procedure for the treatment of myopia and myopic astigmati sm. Although in close to half of the eyes HOAs could be reduced, there was still undercorrection and induction of HOAs with the algorithm employed.
文摘Background: Vitreoretinal complications are rare in laser in situ keratomileusis (LASIK). Increase in intraocular pressure caused by intraoperative suction with subsequent deforming of the ocular globe and excimer laser shock during the ablation have been discussed as possible causes. The purpose of this study was to determine the effect of LASIK on the vitreous body. Patients and methods: In a prospective study we performed ocular ultrasonography (B scan) immediately before and 1 week after LASIK procedure in 103 myopic or myopic astigmatic eyes (53 patients, mean age 36.3 years, 32 women, 21 men). In particular, the prevalence, localization, and extent of posterior vitreous detachment (PVD) were determined. Results: The mean spherical equivalent was- 4.85 D (range- 1.25 to- 8.38) and the mean anteroposterior ocular globe length was 25.13 mm (range 23.31- 27.65). Ninety-five eyes (92.2% ) had no PVD preoperatively. Nine eyes out of this group (seven patients, 9.5% ) developed incomplete PVD as assessed 1 week postoperatively. Eight eyes (7.8% ) had a partial PVD preoperatively and in only one eye was an extension of vitreous detachment observed after the surgery. None of the preoperatively measured parameters could predict the occurrence of PVD by LASIK. Conclusions: LASIK may in rare cases lead to new occurrence of PVD or extension of a previously existing partial PVD.
