? AIM: To investigate the association of ganglion cell complex thickness (GCCt), global loss volume percentage (GLV%), and focal loss volume percentage (FLV%) with structural and functional findings among patients with chronic central serous chorioretinopathy (CCSC) and recurrent central serous chorioretinopathy (RCSC) by optical coherence tomography (OCT). ? METHODS: Among 29 patients with monocular affected central serous chorioretinopathy (CSC), 15 had CCSC, and 14 had RCSC. The GCCt, FLV%, GLV%, and subfoveal choroidal thickness (SFCT) and sublesional choroidal thickness (SLCT) values were determined using OCT, and the association of these characteristics with neural structure parameters, choroidal morphology, features and functional alterations were estimated for the CCSC and RCSC patients. ? RESULTS: In CCSC, the affected eyes had significantly lower GCCt values than the fellow eyes in the macular regions (all P<0.05), with the highest GCCt observed in the inferior area. A significant association was found between the GCCt in different regions and the change in best corrected visual acuity (BCVA; r=-0.696;-0.695;-0.694, P<0.05) in CCSC patients. A statistically significant moderate negative correlation indicated that long-term CCSC was associated with greater differences in the GCCt in different regions between affected and fellow eyes (r=-0.562; r=-0.556; r=0.525, P<0.05). Additionally, observation of thickened SFCT was associated with a worse FLV% (r=0.599; r=0.546, P<0.05) in both groups. Similarly, thickened SLCT was associated with FLV% in RCSC patients (r=0.544, P<0.05). ? CONCLUSION: The distribution and GCCt are associated with the duration and visual outcomes of CCSC, whereas there is no correlation among RCSC patients. FLV% may be instrumental in differentiating the various outer choroidal vessels (pachyvessels) in long-term CSC. These results suggest that neural structure parameters may aid in estimating and predicting the recovery of altered morphology and function in CCSC and RCSC patients.

AIM To describe the clinical characteristics of eyes using multimodal imaging features with acute macular neuroretinopathy (AMN) lesions following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. METHODS Retrospective case series study. From December 18, 2022 to February 14, 2023, previously healthy cases within 1-week infection with SARS-CoV-2 and examined at Tianjin Eye Hospital to confirm the diagnosis of AMN were included in the study. Totally 5 males and 9 females [mean age: 29.93±10.32 (16-49)y] were presented for reduced vision, with or without blurred vision. All patients underwent best corrected visual acuity (BCVA), intraocular pressure, slit lamp microscopy, indirect fundoscopy. Simultaneously, multimodal imagings fundus photography (45° or 200° field of view) was performed in 7 cases (14 eyes). Near infrared (NIR) fundus photography was performed in 9 cases (18 eyes), optical coherence tomography (OCT) in 5 cases (10 eyes), optical coherence tomography angiography (OCTA) in 9 cases (18 eyes), and fundus fluorescence angiography (FFA) in 3 cases (6 eyes). Visual field was performed in 1 case (2 eyes). RESULTS Multimodal imaging findings data from 14 patients with AMN were reviewed. All eyes demonstrated different extent hyperreflective lesions at the level of the inner nuclear layer and/or outer plexus layer on OCT or OCTA. Fundus photography (45° or 200° field of view) showed irregular hypo-reflective lesion around the fovea in 7 cases (14 eyes). OCTA demonstrated that the superficial retinal capillary plexus (SCP) vascular density, deep capillary plexus (DCP) vascular density and choriocapillaris (CC) vascular density was reduced in 9 case (18 eyes). Among the follow-up cases (2 cases), vascular density increased in 1 case with elevated BCVA; another case has vascular density decrease in one eye and basically unchanged in other eye. En face images of the ellipsoidal zone and interdigitation zone injury showed a low wedge-shaped reflection contour appearance. NIR image mainly show the absence of the outer retinal interdigitation zone in AMN. No abnormal fluorescence was observed in FFA. Corresponding partial defect of the visual field were visualized via perimeter in one case. CONCLUSION The morbidity of SARS-CoV-2 infection with AMN is increased. Ophthalmologists should be aware of the possible, albeit rare, AMN after SARS-CoV-2 infection and focus on multimodal imaging features. OCT, OCTA, and infrared fundus phase are proved to be valuable tools for detection of AMN in patients with SARS-CoV-2.

Background Form deprivation myopia is a type of ametropia, with identifiable causes in humans, that has been induced in many animals. The age of onset of myopia induced by monocular form deprivation coincides with the period of visual development in guinea pigs. However, visual acuity of form-deprived eyes in guinea pigs is not understood yet. In this study, we investigated whether monocular form deprivation would affect visual acuity in infant guinea pigs by evaluating the development of myopia and amblyopia after monocular form deprivation, and whether form deprivation myopia and amblyopia occurred simultaneously or successively. Methods Twenty pigmented guinea pigs (2 weeks old) were randomly assigned to two groups: monocularly form-deprived (n=10), in which facemasks modified from latex balloons covered the right eye, and normal controls (n=10). Refraction, axial length, and visual acuity were measured at 4 intervals (after 0, 1, 4, and 8 weeks of form deprivation), using cycloplegic streak retinoscopy, A-scan ultrasonography (with an oscillation frequency of 10 MHz), and sweep visual evoked potentials (sweep VEPs), respectively. Sweep VEPs were performed with correction of the induced myopic refractive error. Results Longer deprivation periods resulted in significant refractive errors in form-deprived eyes compared with those in contralateral and normal control eyes; the axial lengths of form-deprived eyes increased significantly after 4 and 8 weeks of form deprivation. These results revealed that myopia was established at 4 weeks. The acuity of form-deprived eyes was unchanged compared to that at the pretreatment time point, while that of contralateral eyes and eyes in normal control guinea pigs improved; there were significant differences between the deprived eyes and the other two open eyes from 1 to 8 weeks of form deprivation, showing that amblyopia was possibly established during 1 week of form deprivation. Conclusions This study demonstrated the feasibility of using sweep VEPs to estimate the visual acuity of guinea pigs. Further, our results revealed that amblyopia likely occurred earlier than myopia; amblyopia and myopia coexisted after a long duration of monocular form deprivation in guinea pigs. Understanding this relationship may help provide insights into failures of treatment of amblyopia associated with myopic anisometropia.

To measure the retinal microvascular density in patients with anisometropic amblyopia using optical coherence tomographic angiography (OCTA) and to evaluate the effects of successful amblyopia treatment on microvasculature in retina. 59 children (5–12 years old) including 22 newly diagnosed unilateral anisometropic amblyopia, 16 recovered unilateral anisometropic amblyopia, and 21 control children were imaged with OCTA using 6 × 6-mm macular scan pattern. Vessel densities of the superficial capillary plexus (SCP), the deep capillary plexus (DCP), and the overall macular thickness were acquired and compared among the three groups. After adjustment for axial length, the amblyopia group showed lower macular vessel density in the SCP ( P = 0.005) and in the DCP ( P = 0.004) compared with that of the control group. However, for the recovered amblyopia group, no difference of vessel density was found when compared with the control group in both the SCP ( P = 0.548) and the DCP ( P = 0.124). No difference of the mean macular thickness was found among three groups ( P ≥ 0.15). Children with anisometropic amblyopia have reduced macular vessel density in OCTA, while no difference of macular vessel density was found between the recovered amblyopic and control eyes. Macular thickness showed no difference in anisometropic amblyopia and remained unchanged after amblyopic treatment.

Purpose. To report the application of 14-MHz ultrasonography with tissue harmonic imaging (14 MHz + THI) to determine the integrity of the posterior capsule (PC) in traumatic cataract (TC). Methods. Patients with TC who were scheduled to undergo cataract extraction and whose PC could not be observed by slit lamp examination were included in the study. The status of the PC was determined by 14 MHz + THI before cataract extraction and confirmed during surgery. The results regarding PC integrity obtained from 14 MHz + THI and intraoperative direct observation were compared. Result. The study enrolled 52 eyes of 52 patients (49 men and 3 women), with a mean age of 42.15 years ± 11.23 (SD). The nature of the trauma was blunt (3 eyes) or sharp (49 eyes). The 14 MHz + THI method showed 21 PCs to be intact and 31 to have ruptured before cataract surgery. During surgery, 23 PCs were observed to be intact, while 29 PCs were ruptured. 27 PCs were ruptured and 19 were intact, as determined by the two methods. The 14 MHz + THI observations were consistent with the intraoperative observations of the PC (kappa = 0.764), with no significant difference between the two methods (P=0.687). The sensitivity, specificity, and accuracy of 14 MHz + THI for observation of the PC were 93.10%, 82.60%, and 88.46%, respectively. Conclusion. The 14 MHz + THI method can accurately reveal the integrity of the PC in TC. It has important clinical value in the selection of cataract surgery methods and the prediction of complications during TC surgery.

目的 探讨年龄相关性白内障超声乳化联合人工晶体(Phaco+IOL)植入术医嘱化临床路径(CP)的运行现状.方法 分析天津市眼科医院白内障专业2014-2016年引入医嘱化CPIS并施行Phaco+IOL植入术的单纯年龄相关性白内障患者14 163例(14 163只患眼)的CP技术指标和变异监测指标.结果 3年平均入径率为98.80％,完成率为99.60％,变异率为15.00％;变异原因方面,患者因素占93.50％,医院因素占6.50％;变异构成方面,负性变异占93.66％,正性变异占5.71％,退径占0.63％.2014-2016年入径率分别为98.64％、98.42％、99.32％,完成率分别为99.38％、99.69％、99.73％,差异均有统计学意义(P＜0.01);变异率分别为15.84％、14.22％、14.95％,差异无统计学意义(P＞0.05);其中负性变异分别为92.49％、93.97％、94.72％,差异有统计学意义(P＜0.01),而患者因素比重最大,分别为97.38％、97.39％、97.52％,差异无统计学意义(P＞0.05).结论 医嘱化CPIS有效控制了年龄相关性白内障Phaco+IOL植入术CP的各项指标,保证其顺利实施.负性变异在总变异中的比例过高,提示CPIS仍需进一步改进.

目的 探讨浸润式B超引导下A超分段声速与浸润式A超分段声速在白内障患者眼轴长度生物测量中结果的一致性.方法 随机抽取天津市眼科医院2014年4月1日-5月1日收治的白内障患者60例(60只眼)为研究对象,所有患者均分别进行浸润式B超引导下A超分段声速生物测量及浸润式A超分段声速生物测量,比较两种测量方式的眼轴长度.结果 浸润式A超分段声速生物测量患眼眼轴长度平均为(24.20±2.06) mm,浸润式B超引导下A超分段声速生物测量患眼眼轴长度平均为(24.19±2.06) mm,差异无统计学意义(t=-0.675,P＞0.05).结论 浸润式B超引导下A超分段声速生物测量与浸润式A超分段声速生物测量有着相同的安全性和准确性,而前者为实时二维图像,具有更好的可重复性,可以更好地显示待测眼内各组织的形态及位置关系,确保白内障患眼眼轴长度的准确测量.

AIM:To compare the results of axial length (AL) biometry in cataract eyes by three methods: immersion B-ultrasound (IB) biometry, immersion A-ultrasound (IA) biometry and optical low coherence reflectometry.METHODS:In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient.RESULTS:Eighty eyes of 80 patients (39 men and 41 women) for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance (P=0.97); the mean difference in AL measurements was -0.031 mm (P=0.26; 95%CI, -0.09 to 0.02); linear regression showed an excellent correlation (r=0.98, P<0.0001). Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance (IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07); linear regression showed an excellent correlation (IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96); Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement (LoA), -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm].CONCLUSION:Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

Objective To evaluate the accuracy of the biometry using immersion B scan and partial coherence interferometry (Lenstar LS900) for the axial length (AL) of silicone oil-filled eyes respectively.Methods Thirty-five silicone oil-filled eyes (38 patients) were included in the study.All of these eyes underwent silicone oil removal,cataract extraction and intraocular lenses implantation.The AL of all the silicone oil-filled eyes was measured with A/B-scan ultrasound and Lenstar LS900 before operation and with Lenstar LS900 after operation.The measured distance was compared respectively.The method of immersion B-scan guided with respective sonic velocity.AL was the sum of corneal thickness,anterior chamber depth,lens thickness,the apparent length of oil bubble (velocity values 996 m/s),the depth of the water layer beneath the oil bubble.Results Thirty-one eyes were measured with Lenstar LS900 before silicone oil removal,and the mean AL was (24.12± 1.70) mm,7 eyes failed to get the results before the operation;36 eyes were measured with Lenstar LS900 after silicone oil removal,and the mean AL was (24.45±1.89) mm.All eyes were measured with B-scan before silicone oil removal,and the mean AL was (24.87±2.52) mm.The difference (31 eyes) of AL measurement before silicone oil removal by two methods was (-0.00±0.09) mm;the difference (31 eyes) between pre-and post-surgical AL measurement with Lenstar LS900 was (0.02±0.07) mm;the difference (36 eyes) between pre-surgical AL measured with B-scan and post-surgical AL measured with Lenstar LS900 was (-0.02±0.11) mm.All the differences were not statistically significant (t=-0.205,1.752,-1.280;P＞ 0.05).The consistency of the results measured by two methods was well in Bland-Ahamn analysis.Conclusions Measurement results of AL between immersion B-scan guided with respective sonic velocity and Lenstar LS900 are high repeatability on silicone oil-filled eyes.The AL of silicone oil-filled eyes can be measured reliably by immersion B-scan guided with respective sonic velocity.

Objective To compare the applied signification of optical and ultrasonic biometry in observing the axial length of eyes with vitreous hemorrhage and retinal detachment. Methods This is a prospective clinical study. We randomly selected 57 cases (57 eyes) with vitreous hemorrhage and (or) retinal detachment from May 1, 2016 to May 31. Patients had not been performed eye surgery, also denied the history of ocular trauma and excluded other eye diseases. 25 eyes with vitreous hemorrhage, 24 eyes with retinal detachment, 8 eyes complicated with vitreous and retinal detachment hemorrhage. At 24 hours before surgery, we measured axial length using the Lenstar LS 900, immersion B-ultrasound (IB) and immersion A-ultrasound (IA). The differences between three methods were assessed with paired sample t-test. Results IB and IA data was collected from all 57 eyes, there was no statistical significance between measurements of IB and IA (P > 0.05). In the eyes with serious refractive medium opacity (36 eyes), the results showed no statistical significance difference between measurements of IB and IA (P > 0.05). The measurements of three groups can be obtained from the rest eyes (21 eyes): significant statistical difference of the measurements between IB and Lenstar was detected[(24.057±1.441)mm vs(23.470±1.775)mm],(t=3.099, P < 0.05) same results between IA and Lenstar was obtained [(23.962±1.443) mm vs (23.470±1.775) mm], difference was statistically significant (t=2.643, P < 0.05). But the measurements showed no statistical significance difference between the measurements of IB and IA (P > 0.05). Conclusions In the eyes with vitreous hemorrhage and (or) retinal detachment, the measurements of axial length could not be achieved or existed deviations on account of refractive medium opacity when using optical biometry. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

目的 探讨干眼患者泪膜功能及睑板腺功能随年龄和性别的变化趋势.方法 本研究采用回顾性系列病例研究.选取154例(308眼)来我院就诊的干眼患者为研究对象,其中男76例(152眼),女78例(156眼),通过Oculus角膜地形图眼表综合分析仪,测量每位患者双眼的首次泪膜破裂时间、平均泪膜破裂时间、首次泪膜破裂区域等数据,研究其随年龄及性别变化的规律;同时观察睑板腺形态,统计腺管根数及睑板腺缺失面积,通过睑板腺缺失面积评分系统研究其随年龄及性别变化的规律.结果 干眼患者睑板腺缺失面积评分与年龄存在正相关关系(r =0.715,P＜0.05),其中男性r=0.821,P＜0.05,女性r=0.663,P＜0.05;腺管缺失根数百分比与年龄存在正相关关系(r=0.620,P＜0.05),其中男性r=0.629,P＜0.05,女性r=0.631,P＜0.05.睑板腺缺失面积评分在50～59岁组,男性为(9.47±1.00)分,明显高于女性的(7.53±2.21)分,差异具有统计学意义(P＜0.05);在≥60岁组,男性为(10.69 ±1.20)分,明显高于女性的(9.87±1.70)分,差异具有统计学意义(P＜0.05).泪膜破裂时间与年龄存在负相关关系,其中首次泪膜破裂时间为r=-0.49,P＜0.01,平均泪膜破裂时间为r=-0.54,P＜0.01;除＜30岁组以外,其他各年龄组中平均泪膜破裂时间均大于首次泪膜破裂时间,且差异均具有统计学意义(均为P ＜0.05).泪膜的首次破裂区域集中在角膜鼻下方,占所有分区中的31％.结论 干眼患者在睑板腺的缺失面积及腺管缺失根数方面具有随年龄增长而逐渐加重的趋势,在泪膜破裂时间方面具有随年龄增长而逐渐下降的趋势,各年龄组干眼患者泪膜首次破裂区域集中在角膜鼻下方位置,这对干眼患者的诊断及治疗有一定指导价值.

As an influencing factor of visual quality, straylight is a functional measure of the effect of light scatter across the retina.The phenomenon depends on the refractive index and the turbidity of the ocular media.This light scattering reduces the contrast of the image projected on the retina, and thus decreases the quality of vision.The review focuses on the concept and classification of straylight, and the relationship between straylight and visual quality.

Background Small incision lenticule extraction (SMILE) was a new procedure which is miniinvasion and flapless,but few attentions were paid to the visual quality after SMILE.To understand the changes of intraocular straylight after SMILE is of important significance for the assession of the visual quality after the procedure.Objective This study was to compare the characteristic of straylight between SMILE and femtosecond laser assisted laser in situ keratomileusis (FS-LAISK) after surgery.Methods A retrospective study was designed.Written informed consent was obtained from each patient prior to accepting the surgery.One hundred and twenty-seven eyes of 68 patients with myopia and myopic astigmatism were included in Tianjin Eye Hospital from January 2011 to July 2013.SMILE was performed on 64 eyes of 35 patients and FS-LASIK was carried out in 63 eyes of 33 patients at the same period.Stray light was detected with C-Quant stray light meter before and 1 week,1 month and 6 months after surgery.The changes of stray light values following the surgery were compared between the two groups,and the correlations between postoperative stray light values with operative parameters were analyzed.Results The mean stray light values were (1.03 ±0.19)D and (0.95±0.16)D at 1 week and 1 month after surgery,which were higher than (0.88 ±0.18)D at preoperation in the FS-LASIK group (P =0.000,0.012).The stray light values were (0.98±0.16),(0.95±0.14) and (0.94±0.16)D at 1 week,1 month or 6 months after surgery,and no statistically significant differences were found in comparison with (0.91 ±0.15)D in preoperation in the SMILE group (all at P＞0.05).No significant intergroup difference was seen in the stray light values (Fgroup =0.077,P=0.781).The stray light differences of various time points after surgery and before surgery were increased in the FS-LASIK group compared with SMILE group (Fgroup =14.798,P＜0.001),with the significant difference in postoperative 1 week between the two groups (P＜0.01).The negative correlations were found between stray light values at 1 week,1 month and 6 months after SMILE with the lenticule thickness/central corneal thickness (CCT) (R2=0.123,0.145,0.098,all at P＜0.05) or between stray light change.Conclusions Intraocular stray light appears less change in operative eyes after SMILE.However,intraocular stray light increases in the eyes received FS-LASIK,especially at early stage after operation.The stray light shifts return to normal with the lapse of postoperative time.

PURPOSETo investigate the characteristics of forward light scatter changes after small incision lenticule extraction (SMILE) and to compare these changes with those after femtosecond laser-assisted LASIK (femto-LASIK) and epipolis LASIK (epi-LASIK).METHODSA total of 303 eyes (SMILE group = 118 eyes, femto-LASIK group = 90 eyes, epi-LASIK group = 95) of 157 patients were included in this study. Forward straylight was measured preoperatively and 1 month, 6 months, and 1 year postoperatively using a C-Quant straylight meter (Oculus Optikgeräte, Wetzlar, Germany).RESULTSA significant increase in straylight was found in the femto-LASIK group only at 1 month after the procedure (P = .002), whereas significant increases were found in the epi-LASIK group at 1 month, 6 months, and 1 year after the procedure (P < .001). There were no significant increases in the straylight values after SMILE (P = .310) compared with the preoperative values, although the straylight values were slightly increased at 1 month. Significant differences in the postoperative-preoperative straylight value (Δlog[s]) changes were found between the SMILE, femto-LASIK, and epi-LASIK groups over the follow-up period (P < .001 for all). The correlations between the ablation depth/central corneal thickness ratios and the straylight values were statistically significant in the femto-LASIK and epi-LASIK groups, whereas no significant correlation between the lenticule thickness/central corneal thickness ratios and the stray-light values was found in the SMILE group.CONCLUSIONSForward straylight was slightly increased in the early stage after the femto-LASIK procedure and was significantly increased throughout the follow-up period after epi-LASIK surgery. The SMILE procedure appeared to have a smaller effect on forward light scatter within the 1-year follow-up period.

Objective To investigate the characteristics and relevant factors of intraocular stray light before and after small incision lenticular extraction (SMILE).Methods In a prospective case study,67 myopic and myopic astigmatism patients (67 eyes) underwent SMILE surgery in Tianjin Eye Hospital.Stray light measurements were taken before SMILE surgery and 1 week,1 month,3 months and 6 months after surgery using an Oculus C-Quant stray light meter.Pearson correlation was used to identify correlations in stray light values for such factors as age,spherical equivalent refractive error,central corneal thickness (CCT),mean keratometric value,and corneal curvature radius as well as for surgical factors such as cap diameter,hinge width,ablation depth,ablation ratio,residual bed thickness,RBT/CCT and energy.Results The stray light values preoperatively,and 1 week,1 month,3 months and 6 months after SMILE surgery were 0.93±0.16,0.97±0.14,0.94±0.17,0.94±0.17,and 0.90±0.17,respectively.The mean stray light value was slightly higher 1 week after surgery but no significant differences were found.There were no significant differences when the various time points were compared (F=2.253,P＞0.05).While the changes in stray light values after surgery were not correlated with surgical parameters,there was a slight positive correlation with hinge width at 3 months after surgery (r=0.356,P＜0.01).Conclusion There are no significant differences in stray light between pre-and post-SMILE surgery.It may be possible that a change in stray light could cause a decrease in visual quality.

PURPOSE:To investigate characteristics of straylight before and after thin-flap LASIK performed with femtosecond laser versus with mechanical microkeratome and assess changes at 1 day, 1 week, 1 month, 6 months, and 1 year postoperatively.METHODS:One hundred twenty-eight consecutive eyes from 66 patients were included in this prospective study. Sixty-one eyes of 31 patients had thin-flap LASIK with femtosecond laser. In addition, 67 eyes from 35 patients underwent thin-flap LASIK with mechanical microkeratome were included for comparison. Following flap creation, all eyes were ablated using the VIXS S4 excimer laser system (Visx USA, Inc., Santa Clara, CA). Straylight values were measured using the C-Quant straylight meter (Oculus Optikgeräte GmbH, Wetzlar, Germany) preoperatively and 1 day, 1 week, 1 month, 6 months and 1 year postoperatively.RESULTS:Preoperatively, the mean straylight values were 0.93 ± 0.11. After femtosecond laser-assisted thin-flap LASIK, the values were 1.00 ± 0.11, 0.98 ± 0.10, and 0.99 ± 0.12 at 1 day, 1 week, and 1 month, respectively, and significantly increased (F = 7.62, P > .0001) compared to preoperative values. However, these values decreased and returned to preoperative levels at 6 months and 1 year postoperatively (0.92 ± 0.09 and 0.89 ± 0.13, respectively; P > .05). The postoperative-preoperative increases in straylight were reduced in the femtosecond laser group compared to the mechanical microkeratome group (0.05 ± 0.13 vs 0.10 ± 0.13 at 1 month postoperatively; P < .05). This difference was statistically significant at 1 month postoperatively (P = .04). A negative significant correlation was also found between preoperative straylight values and postoperative-preoperative increases.CONCLUSIONS:Straylight increased significantly in the early stages after femtosecond laser-assisted thin-flap LASIK. However, these values improved over time and gradually returned to preoperative levels, which may be related to the progression of corneal healing.

Background As a newly developed refractive surgery,femtosecond laser in situ keratomileusis (LASIK) receives more and more attention.Changes in ocular stray light after femtosecond LASIK is an important problem that impacts visual quality.Some relevant research has been performed before,but the outcomes are conflicting.Objective This primary study was to investigate the change of stray light values before and after femtosecond LASIK and analyze the relevant factors underlying the change.Methods Clinical data from 109 eyes of 55 myopic patients who underwent femtosecond LASIK in Tianjin Eye Hospital from December,2010 through February,2011 were included in this study.Stray light values were measured and recorded by C-Quant stray light meter preoperatively,and 1 day,1 week,1 month and 6 months postoperatively.The stray light data were compared by repeated measures ANOVA,and the correlations among the stray light values with preoperative factors,such as age,equivalent sphere,pupil diameter and central corneal thickness(CCT),as well as with postoperative factors,such as residual bed thickness(RBT),RBT/CCT,ablation depth,ablation ratio,flap thickness,flap diameter flap base width and exiting energy,were analyzed statistically.Written informed consent was obtained from each individual at initial of this study.Results The stray light values were 0.90±0.19,1.10±0.19,1.02±0.18,0.96±0.16 and 0.94±0.15 pre-operation,and 1 day,1 week,1 month and 6 months after femtosecond LASIK.The stray light values increased significantly 1 day,1 week,and 1 month after surgery,showing significant differences among the various time points (F=17.699,P=0.000).The mean stray light value was higher in 1 week than that in 6 months after operation (t=2.412,P=0.017).No significant differences were found in the stray light values between 6 months and 1 month or pre-operation (t =0.779,P =0.437 ; t =-1.877,P =0.062).No significant correlations were seen between preoperative and postoperative stray light values with age,preoperative refractive diopter,pupil diameter or CCT (P＞0.05).The changes in stray light values 1 week,1 month and 6 months after surgery were negatively correlated with ablation depth(r=-0.226,-0.228,-0.241 ;P＜0.05) and ablation ratio(r =-0.149,-0.219,-0.255 ;P＜0.05).Conclusions Stray light values increase within 1 month and return to normal 6 months after femtosecond LASIK.Stray light values may be related to multiple setting laser parameters and factors during femtosecond LASIK.

Objective To investigate the distribution of corneal thickness in myopic patients and the correlation of corneal thickness,refractive power and corneal curvature in myopia.Methods In a cross-sectional study,a total of 264 people (458 eyes) with myopia or myopic astigmatism were examined.One hundred twenty-two males and 142 females participated in the study.Corneal thickness was measured with a Pentacam system.Measurements were taken at the corneal apex,center point,thinnest point and the average value of all corneal thicknesses measured along 2 mm,4 mm,6 mm and 8 mm diameter rings with the apex location at its center.The average values for corneal thickness and curvature were recorded in an increasingly clockwise direction for the right eyes,and in a counterclockwise direction for the left eyes with the binocular temporal side set to 0°.The subjects were divided into three groups according to refractive error: the low myopia group (refractive error ＜-3.00 D),the moderate myopia group (refractive error ＞-3.00 D and ＜-6.00 D) and the high myopia group (refractive error ＞-6.00 D).ANOVA was used to analyze the differences for the three groups.The different points for corneal thickness between two groups were compared using an independent samples t test.Pearson correlation analysis was used to study the correlation of corneal thickness at different points and the relationship between corneal thickness and other factors.Results The mean values of corneal thickness at the corneal apex、center point and thinnest point were 529.58±22.38 μm,529.75±22.51 μm,and 527.78±22.7 μm.The greatest mean corneal thickness measured along the different diameter rings with the apex location at its center was always at 90 degrees and the mean values were 544.14±22.07 μm,583.15±24.72 μm,646.27±27.34 μm,and 716.52±27.70 μm.The lowest mean corneal thickness measured along the different diameter rings was at 315 degrees,315 degrees,337.5 degrees,and 342 degrees,and the values were 532.48±23.51 μm,549.24±26.97 μm,590.02±27.06 μm,and 657.37±32.03 μm.The mean values of corneal thickness at the corneal apex,center point and thinnest point were found to have a positive correlation between the left and tight eyes (r=0.768,0.548,0.671,P＜0.05).No significant correlation was found between corneal thickness and refractive error or tangential curvature (P＞O.05).Conclusion For the different diameter rings of corneal thickness in myopia,the peripheral corneal thickness values were lowest in the temporal and inferotemporal areas and greatest in the superior area.There was no relationship between corneal thickness and refractive error and corneal curvature.

Objective To evaluate the recovery of central corneal sensitivity and peripheral corneal sensitivity in the early period time after LASIK with femtosecond flaps.Methods In this study,40 cases which underwent LASIK with femtosecond flaps were included.Central,superior,inferior,nasal and temporal comeal sensitivity was measured using a Cochet-Bonnet esthesiometer (Luneau Ophthalmologie) before and 1 week,1 month and 3 months after LASIK with femtosecond flaps.The results were analyzed with Kruskal Wallis H test and Mann-Whitney test by SPSS13.0 software.Results Central,superior,inferior,nasal and temporal comeal sensitivity decreased significantly in the early period time after LASIK with femtosecond flap (P ＜0.05).At every time points of postoperative,superior corneal sensitivity and central,inferior,nasal and temporal corneal sensitivity had significant difference (P ＜0.05).Three months postoperative,central corneal sensitivity was significant lower than the superior,inferior,nasal,temporal.There were no correlations between central corneal sensitivity and central corneal ablation depth,central corneal depth,preoperative spherical equivalent (r =0.005;-0.105; 0,03,P =0.97; 0.38; 0.80). Conclusions Corneal sensitivity is significant decreased in the early period time after LASIK with femtosecond flaps.Comeal sensitivity at the location of the hinge of corneal flaps is decreased lower than other places and the recovery of central corneal sensitivity is slower than other places.There are no correlations between central corneal sensitivity and central corneal ablation depth,central corneal depth,preoperative spherical equivalent.

Objective To investigate the clinical outcomes of VisuMax femtosecond laser flap measured by OCT,to assess the accuracy,repeatability,and regularity of VisuMax femtosecond laser flap.To investigate the change of flap thickness and the factors influencing flap thickness.Methods Sixty-eight eyes of 38 patients who underwent femtosecond LASIK were enrolled in this study and divided into 2 groups depending on the intended flap thicknesses (100μm and 105μm),OCT was used to assess flap thicknesses 1 week,1 month and 6 months postoperatively.The thicknesses of flap and residual bed in the seven measuring points were 1mm,2mm,3mm away from center of cornea on the horizontal and the center of cornea itself.The results were analyzed with t-tset,ANOVA or Pearson correlations test. Results At 1 week,1 month and 6 months after surgery,the thickness of flaps in 100μm and 105μm group was (107.92±5.56)μm,(108.79±4.78)μm,(106.69±5.74)μm and (109.36±6.26)μm,(112.21±4.37)μm,(108.53±7.27)μm respectively.The results of accuracy in 100μm and 105μm groups were (F =4.995,P=0.000; F =1.918,P =0.051; F =1.806,P =0.114) and (F =1.739,P =0.213; F =1.931,P =0.049; F =1.810,P =0.083).Standard deviation of flap thickness in the two groups was 5.56μm,4.78μm,5.74μm and 6.26μm,4.37μm,7.27μm.The results of uniformity in 100μm and 105μm group were (F =5.410,P =0.000; F =8.914,P =0.000; F =3.084,P =0.052) and (F =2.000,P =0.143; F =3.431,P =0.048; F =1.786,P =0.211).The results of comparison of flap thickness in different zones in 100μm and 105μm group were (F =0.919,P =0.409; F =0.701,P =0.504; F =0.547,P =0.584) and (F =1.990,P =0.142; F =4.079,P =0.020; F =1.770,P =0.175) 1 week,1 month and 6 months postoperatively.There was a correlation between uncorrected visual acuity,Q value of back surface of cornea and the thickness of corneal flap measured 6 months after surgery. Conclusions With the time go by,patients have stable visual acuity,Visual femtosecond laser flap thickness has good accuracy,repeatability,the architecture of flaps are uniform and regular.