Background The recent studies have shown that visual performance might be affected by the ocular aberration after the corneal refractive surgery, and try to minimize it. This study was to investigate the effects of ph...Background The recent studies have shown that visual performance might be affected by the ocular aberration after the corneal refractive surgery, and try to minimize it. This study was to investigate the effects of photorefractive keratectomy （PRK） and laser in situ keratomileusis （LASIK） on the higher order of wavefront aberration and analysis of their characteristics. Method This prospective study involved 32 eyes with similar refractive powers （-5.0 D to -6.0 D preoperatively）. LASIK and PRK were performed with the same parameters of 6 mm diameter optical zone and 7 mm diameter transition zone ablation. Wavefront aberrations were tested using a ray tracing technique preoperatively and 3 months postoperatively. Three measurements were obtained for each condition; the root mean squared wavefront error （RMS）, values for overall wavefront aberrations and each order of the Zernike aberrations were analyzed using the Matlab software. The 2-tailed t test was used for statistical analysis. Results Overall higher order aberrations were increased from （0.55±0.26） pm preoperatively to （0.93±0.37） pm for PRK and （0.79±0.38） pm for LASlK postoperatively. This was a 1.69 fold increase in the PRK group （t=3.95, P〈0.001） and a 1.43 fold increase in the LASIK group （t=2.60, P〈0.05）. At 3 months, the mean RMS value for higher-order （3rd to 6th） were significantly increased compared with the corresponding preoperative values （P〈0.05）. The fourth order aberrations, spherical like aberration, were dominant by a 2.64 fold in PRK and a 2.31 fold in LASIK. Different influences of the PRK group and LASIK group were shown in the various zernike components. The statistically significant differences were seen in C4^0. C4^4. C5^3,C5^3. C5^5 and C6^2 of the PRK group and C3^-3, C4^0, C5^-5, C5^5, C6^-2 of the LASIK group, which represents a 7.42, 3.58, 9.21,2.72 and 5.3 ford increases in PRK group, and 6.40, 10.80, 11.06, 3.47 and 6.09 fold increases in LASIK group, respectively. C3^3 in展开更多
Background Laser in situ keratomileusis （LASIK） has become an efficient and commonly performed procedure to reduce refractive errors. In order to further increase the postoperative visual quality, the wavefront-guid...Background Laser in situ keratomileusis （LASIK） has become an efficient and commonly performed procedure to reduce refractive errors. In order to further increase the postoperative visual quality, the wavefront-guided refractive surgery has been a research hotspot in customized surgery. This study was conducted to compare the visual acuity, higher-order aberration, and contrast sensitivity of wavefront-guided LASIK with iris-registration and conventional LASIK. Methods Two hundred and eleven myopic eyes of 109 patients were enrolled in this prospective study and randomly divided into two groups： the wavefront-guided LASIK （wg LASIK） group （94 eyes） and conventional LASIK group （117 eyes）. A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square （RMS） of higher order aberrations with 6.0 mm pupil size, and Optec 6500 visual function instrument was used to measure contrast sensitivity （CS） under 5 spatial frequencies before and after surgery in both groups.Results The uncorrected visual acuity （UCVA） and the mean spherical equivalent （SE） in wg LASIK group were significantly better than those in conventional LASIK （UCVA, z=2.339, P=0.019; SE, t=2.838, P=0.005） at 3 months after surgery. Moreover, the increase in Z3^-3, Z3^1, Z3^3, Z4^0, Z5^-1, Z5^1 Z5^-5 and Z6^-6 in wg LASIK group was statistically smaller than that in conventional LASIK group （P〈0.05）. In wg LASIK group, eyes with a higher amount of the preoperative RMS of the higher order aberrations （RMSh≥0.30μm） showed a statistically lower increase （13.5%） than those in conventional LASIK group at 3 months after surgery （33.3%） （P=0.004）. And the values of 4th order spherical aberration （4thSA） and the root mean square of 6th order aberration （RMS6） in wg LASIK group were significantly lower than those in conventional group in eyes which had higher preoperative astigmatism （≥1.0D） （4thSA, P=0.03; RMS6, P=0.02）. Wg LASIK group showed bett展开更多
基金Tianjin Scientific Nature Found (No. 033606011).
文摘Background The recent studies have shown that visual performance might be affected by the ocular aberration after the corneal refractive surgery, and try to minimize it. This study was to investigate the effects of photorefractive keratectomy （PRK） and laser in situ keratomileusis （LASIK） on the higher order of wavefront aberration and analysis of their characteristics. Method This prospective study involved 32 eyes with similar refractive powers （-5.0 D to -6.0 D preoperatively）. LASIK and PRK were performed with the same parameters of 6 mm diameter optical zone and 7 mm diameter transition zone ablation. Wavefront aberrations were tested using a ray tracing technique preoperatively and 3 months postoperatively. Three measurements were obtained for each condition; the root mean squared wavefront error （RMS）, values for overall wavefront aberrations and each order of the Zernike aberrations were analyzed using the Matlab software. The 2-tailed t test was used for statistical analysis. Results Overall higher order aberrations were increased from （0.55±0.26） pm preoperatively to （0.93±0.37） pm for PRK and （0.79±0.38） pm for LASlK postoperatively. This was a 1.69 fold increase in the PRK group （t=3.95, P〈0.001） and a 1.43 fold increase in the LASIK group （t=2.60, P〈0.05）. At 3 months, the mean RMS value for higher-order （3rd to 6th） were significantly increased compared with the corresponding preoperative values （P〈0.05）. The fourth order aberrations, spherical like aberration, were dominant by a 2.64 fold in PRK and a 2.31 fold in LASIK. Different influences of the PRK group and LASIK group were shown in the various zernike components. The statistically significant differences were seen in C4^0. C4^4. C5^3,C5^3. C5^5 and C6^2 of the PRK group and C3^-3, C4^0, C5^-5, C5^5, C6^-2 of the LASIK group, which represents a 7.42, 3.58, 9.21,2.72 and 5.3 ford increases in PRK group, and 6.40, 10.80, 11.06, 3.47 and 6.09 fold increases in LASIK group, respectively. C3^3 in
文摘Background Laser in situ keratomileusis （LASIK） has become an efficient and commonly performed procedure to reduce refractive errors. In order to further increase the postoperative visual quality, the wavefront-guided refractive surgery has been a research hotspot in customized surgery. This study was conducted to compare the visual acuity, higher-order aberration, and contrast sensitivity of wavefront-guided LASIK with iris-registration and conventional LASIK. Methods Two hundred and eleven myopic eyes of 109 patients were enrolled in this prospective study and randomly divided into two groups： the wavefront-guided LASIK （wg LASIK） group （94 eyes） and conventional LASIK group （117 eyes）. A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square （RMS） of higher order aberrations with 6.0 mm pupil size, and Optec 6500 visual function instrument was used to measure contrast sensitivity （CS） under 5 spatial frequencies before and after surgery in both groups.Results The uncorrected visual acuity （UCVA） and the mean spherical equivalent （SE） in wg LASIK group were significantly better than those in conventional LASIK （UCVA, z=2.339, P=0.019; SE, t=2.838, P=0.005） at 3 months after surgery. Moreover, the increase in Z3^-3, Z3^1, Z3^3, Z4^0, Z5^-1, Z5^1 Z5^-5 and Z6^-6 in wg LASIK group was statistically smaller than that in conventional LASIK group （P〈0.05）. In wg LASIK group, eyes with a higher amount of the preoperative RMS of the higher order aberrations （RMSh≥0.30μm） showed a statistically lower increase （13.5%） than those in conventional LASIK group at 3 months after surgery （33.3%） （P=0.004）. And the values of 4th order spherical aberration （4thSA） and the root mean square of 6th order aberration （RMS6） in wg LASIK group were significantly lower than those in conventional group in eyes which had higher preoperative astigmatism （≥1.0D） （4thSA, P=0.03; RMS6, P=0.02）. Wg LASIK group showed bett
