Background: The purpose is to investigate the relationship between full-thickness macular hole(MH) and retinal break(RB) and/or lattice degeneration.Methods: Patients diagnosed as full-thickness MH and referred to Dr....Background: The purpose is to investigate the relationship between full-thickness macular hole(MH) and retinal break(RB) and/or lattice degeneration.Methods: Patients diagnosed as full-thickness MH and referred to Dr. Lin Lu from January 2009 to December 2013 were evaluated. All patients underwent general ophthalmologic examinations, fundus examination and optical coherence tomography(OCT). The RB and/or lattice degeneration were recorded.Results: Totally 183 eyes of 167 patients were included. The sex ratio of men to women was 1:2.88. A total of 17 eyes were pseudophakic and 166 eyes were phakic. RB and/or lattice degeneration were found in 62 eyes(33.88%). The prevalence of RB and/or lattice degeneration was similar between men and women(P=0.344>0.05). There was no statistical difference between the pseudophakic eyes and phakic eyes(P=0.138>0.05). All of the RB and/or lattice degeneration were located near or anterior to the equator. The inferior quadrants and the vertical meridian were af ected more often than the superior quadrants and the horizontal meridian.Conclusions: We identified a high incidence of RB/lattice degeneration in cases of full-thickness MH. Carefully examination of the peripheral retina and prophylactic treatment of RB and/or lattice degeneration are critical.展开更多
AIM: To investigate the efficacy of non-buckled vitrectomy with classical endotamponade agents in the treatment of primary retinal detachment (RD) complicated by inferior breaks and proliferative vitreoretinophathy (P...AIM: To investigate the efficacy of non-buckled vitrectomy with classical endotamponade agents in the treatment of primary retinal detachment (RD) complicated by inferior breaks and proliferative vitreoretinophathy (PVR). METHODS: A retrospective, consecutive and case series study of 40 patients with inferior break RD and PVR >= C1 was conducted. All patients underwent a standard 3-port 20-gauge pars plana vitrectomy (PPV) with gas or silicone oil tamponade without supplementary scleral buckling. The vitreous and all proliferative membrane were completely removed, and retinectomy was performed when necessary. The mean follow-up was 12.5 months. The primary and final anatomic success rate, visual acuity and complications were recorded and analyzed. RESULTS: Primary anatomic success rate was achieved in 35 of 40 eyes (87.5%) and the final anatomic success rate was 100%. The most common cause of redetachment was recurrent PVR. The best-corrected visual acuity (BCVA) at final follow-up was improved in 34 eyes (85%), remained stable in 1 eye (2.5%), and worsened in 5 eyes (12.5%). The mean visual acuity at final follow-up was improved significantly (P=0.000). CONCLUSION: This retrospective study provides evidence that vitrectomy without scleral buckling seemed to be an effective treatment for inferior break RD with PVR. With complete removal of vitreous and proliferative membranes and timing of retinectomy, the inferior breaks which complicated with PVR could be dosed successfully without additional sclera! buckling.展开更多
AIM:To compare success rates and complications of Densiron 68 and 1000cSt silicone oil (SO) in the management of rhegmatogenous retinal detachment (RRD) with inferior breaks (IBs). METHODS:Totally 61 eyes of 61 consec...AIM:To compare success rates and complications of Densiron 68 and 1000cSt silicone oil (SO) in the management of rhegmatogenous retinal detachment (RRD) with inferior breaks (IBs). METHODS:Totally 61 eyes of 61 consecutive patients with RRD with IBs were assigned to pars plana vitrectomy (PPV) with Densiron (n =31) or PPV with SO (n=30) in order of presentation. SO and Densiron removal was performed 3 months after initial surgery. Follow up visits were terminated 6 months after SO removal. ·RESULTS:With a single operation, the Densiron group showed 84% and SO 74% reattachment. With further surgery, both groups showed 90% reattachment. Complications such as cataract, raised intraocular pressure (IOP), inflammatory reaction, macular epiretinal membranes, and emulsification of SO were seen in both groups. CONCLUSION:Densiron and SO are found to have similar success rates and complications.展开更多
AIM:To assess the efficacy and safety of parafoveal retinal massage combined with autologous whole blood cover in the treatment of refractory macular holes(MHs)and present the surgical procedure.METHODS:Patients with ...AIM:To assess the efficacy and safety of parafoveal retinal massage combined with autologous whole blood cover in the treatment of refractory macular holes(MHs)and present the surgical procedure.METHODS:Patients with giant(minimum diameter>800 pm),recurrent or persistent MHs who underwent PPV combined with parafoveal retinal massage and autologous whole blood cover using C3F8 as tamponade agent from February 2018 to May 2019 were enrolled in this retrospective study.After surgery,all patients were informed to maintain a prone position for at least 7d.Preoperative and postoperative best-corrected visual acuities(BCVAs)were compared and MH closure rate was measured as the main outcome.RESULTS:A total of 13 MH patients consisted of 6 giant MHs,4 persistent holes and 3 recurrent holes(5 men and 8 women;average age was 56.40±11.72y)were enrolled in this study.MH closure was achieved in 11 eyes by this modified surgical technique while 2 eyes failed.Revitrectomy with autologous neurosensory retinal patch transplantations was applied for those 2 patients and then both holes were closed.No intraoperative complications were observed.BCVA improved from 1.73 IogMAR to 0.74 IogMAR at 6mo postoperation.There was significant difference in BCVA before versus after the surgery(P<0.05).There were no adverse events occurred during the follow-up period.CONCLUSION:With easier surgical procedure,parafoveal retinal massage combined with autologous whole blood cover is an effective addition to the surgical options for the management of refractory MHs.展开更多
The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable...The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable in this context.This study examines the variation of rock fracture length,fracture tortuosity,hole size,and rock breaking efficiency for a different number of holes and laser power,based on the constant total energy of laser irradiation.As indicated by the results,increasing the laser power increases the laser intensity,which helps increase the hole diameter and depth.Moreover,for the same laser power,increasing the number of irradiated holes reduces the laser energy absorbed by each hole,which is not conducive to increasing the hole depth.As the number of holes increases,the mass loss of the rock also increases,while both specific energy(SE)and modified specific energy(MSE)decrease.When the number of holes remains the same,the mass of the shale removed by low power is less than that removed by high power,while SE and MSE have an inverse relation with power.Therefore,high laser power and multiple-hole irradiation are more conducive to rock breaking.Besides,the fracture length and fracture tortuosity of the rock irradiated by the low laser power will increase first and then decrease with the increase in the number of holes,and reach the peak value when the irradiation takes place through three holes.When a high-power laser irradiates the rock,the fracture length and tortuosity will increase with the increase in the number of irradiation holes.This is because a rock irradiated by low power dissipates more energy,with the result that the energy absorbed by the sample with four irradiation holes is not enough to break the rock quickly.This study is expected to provide some guidance to break rock for drilling deep reservoirs and hard rock formations using laser irradiation.展开更多
AIM: To evaluate anatomical and visual outcomes of episcleral macular buckling (EMB) for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole.METHODS: Five cases of EMB for init...AIM: To evaluate anatomical and visual outcomes of episcleral macular buckling (EMB) for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole.METHODS: Five cases of EMB for initial failure of retinal reattachment after internal limiting membrane (ILM) peeling and silicone oil tamponade caused by myopic macular hole were retrospectively reviewed. A silicone sponge sutured directly across the macular region was performed on the silicone oil filled eyes. Silicone oil was removed no sooner than 1 month post- EMB. The duration of follow -up time after removal of silicone oil was more than 3 months.RESULTS: Retinas of five eyes were all reattached at the last follow-up. The postoperative vision ranged from counting fingers to 0.08.CONCLUSION: Anatomical results improved after EBM for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole, which was not evident for visual outcome.展开更多
AIM:To evaluate the therapeutic effect of amniotic membrane(AM)for covering high myopic macular hole associated with retinal detachment following failed primary surgery.METHODS:Seventeen eyes of 17 patients whose axia...AIM:To evaluate the therapeutic effect of amniotic membrane(AM)for covering high myopic macular hole associated with retinal detachment following failed primary surgery.METHODS:Seventeen eyes of 17 patients whose axial length was more than 29 mm suffered from macular hole(MH)or MH associated with retinal detachment(RD),and had previously surgery of pars plana vitrectomy(PPV)with internal limiting membrane(ILM)peeling and silicone oil(SO)tamponade.Half a year after the surgery,optical coherence tomography(OCT)showed that MH did not heal in all 17 eyes and RD was still maintained in 13 eyes of these 17 eyes.We performed SO removal combined with AM covering on macular area and C3 F8 tamponade,and phacoemulsification combined with intraocular lens implantation simultaneously cataract eyes.We followed up these patients for one year.RESULTS:In all 17 eyes,SO was removed successfully,MHs were healed and RDs were reattached.One eye(5.89%,1/17)had AM shifted half a month after surgery and underwent a second surgery to adjust the position of the AM and supplement C3 F8.After surgery,the visual acuity(VA)improved in 15 eyes(88.24%,15/17),no change in two eyes(11.76%,2/17).No serious complications occurred in all eyes.CONCLUSION:AM covering is helpful to rescue the previous failure surgery of high myopic MH.展开更多
AIM: To evaluate the causes and associations of missed retinal breaks(MRBs) and posterior vitreous detachment(PVD) in patients with rhegmatogenous retinal detachment(RRD).METHODS: Case sheets of patients under...AIM: To evaluate the causes and associations of missed retinal breaks(MRBs) and posterior vitreous detachment(PVD) in patients with rhegmatogenous retinal detachment(RRD).METHODS: Case sheets of patients undergoing vitreo retinal surgery for RRD at a tertiary eye care centre were evaluated retrospectively. Out of the 378 records screened, 253 were included for analysis of MRBs and191 patients were included for analysis of PVD,depending on the inclusion criteria. Features of RRD and retinal breaks noted on examination were compared to the status of MRBs and PVD detected during surgery for possible associations.RESULTS: Overall, 27% patients had MRBs. Retinal holes were commonly missed in patients with lattice degeneration while missed retinal tears were associated with presence of complete PVD. Patients operated for cataract surgery were significantly associated with MRBs(P =0.033) with the odds of missing a retinal break being1.91 as compared to patients with natural lens. Advanced proliferative vitreo retinopathy(PVR) and retinal bullae were the most common reasons for missing a retinal break during examination. PVD was present in 52% of the cases and was wrongly assessed in 16%. Retinal bullae,pseudophakia/aphakia, myopia, and horse shoe retinal tears were strongly associated with presence of PVD.Traumatic RRDs were rarely associated with PVD. CONCLUSION: Pseudophakic patients, and patients with retinal bullae or advanced PVR should be carefully screened for MRBs. Though Weiss ring is a good indicator of PVD, it may still be over diagnosed in some cases. PVD is associated with retinal bullae and pseudophakia, and inversely with traumatic RRD.展开更多
AIM: To observe the clinical effect of pars plana vitrectomy(PPV) and silicone oil filling surgery combined with intraoperative posterior scleral staphyloma(PS) marginal retinal photocoagulation in the treatment of hi...AIM: To observe the clinical effect of pars plana vitrectomy(PPV) and silicone oil filling surgery combined with intraoperative posterior scleral staphyloma(PS) marginal retinal photocoagulation in the treatment of high myopic macular hole retinal detachment(MHRD) with PS.METHODS: This was a retrospective clinical study. From May 2017 to March 2020, 62 MHRD patients with PS(62 eyes) were enrolled in the study. Patients were divided into 23 G PPV combined with PS marginal retina intraoperative photocoagulation group(combined group) and conventional surgery group(conventional group), with 31 eyes in each. Triamcinolone acetonide and indocyanine green were used to remove the epiretinal membrane and the posterior macular inner limiting membrane(ILM). In the combined group, 2 to 3 rows of retinal photocoagulation were performed on the edge of the PS. The patients were followed up for an average of 8.34±3.21 mo. The first retinal reattachment rate, macular hole closure rate, Duration of silicone oil tamponade, best corrected visual acuity(BCVA) and average number of operations were observed and compared between the two groups.RESULTS: The first retinal reattachment rates of the eyes in the combined group and the conventional group were 96.7%(29/31) and 67.7%(21/31), respectively(χ~2=6.613, P=0.010). The macular hole closure rates in the combined group and the conventional group were 74.2%(23/31) and 67.7%(21/31), respectively(χ~2=0.128, P=0.721). The Duration of silicone oil tamponade of the patients in the combined group was lower than that of the routine group(t=-41.962, P≤0.001). Postoperative log MAR BCVA values of patients in the combined group and the conventional group were 1.27±0.12 and 1.26±0.11, compared with the log MAR BCVA before surgery, each group was improved(t=19.947, t=-19.517, P≤0.001, P≤0.001). There was no significant difference in the log MAR BCVA between the eyes of the two groups(t=-0.394, P=0.695). The average numbers of operations on the eyes in the conventional group and the combined group were 2.39±0.62 and 2.06±0.25 times, the combined group had fewer operations on average(t=-2.705, P=0.009). CONCLUSION: Intraoperative PPV treatment of MHRD with PS combined with PS marginal endolaser photocoagulation can effectively increase the rate of retinal reattachment after the first operation, reduce the number of repeated operations, and reduce the postoperative duration of silicone oil tamponade.展开更多
The characteristics of the flow field associated with a multi-hole combined external rotary bit have been studied by means of numerical simulation in the framework of an RNG k-εturbulence model,and compared with the ...The characteristics of the flow field associated with a multi-hole combined external rotary bit have been studied by means of numerical simulation in the framework of an RNG k-εturbulence model,and compared with the results of dedicated rock breaking drilling experiments.The numerical results show that the nozzle velocity and dynamic pressure of the nozzle decrease with an increase in the jet distance,and the axial velocity of the nozzle decays regularly with an increase in the dimensionless jet distance.Moreover,the axial velocity related to the nozzle with inclination angle 20°and 30°can produce a higher hole depth,while the radial velocity of the nozzle with 60°inclination can enlarge the hole diameter.The outcomes of the CFD simulations are consistent with the actual dynamic rock breaking and pore forming process,which lends credence to the present results and indicates that they could be used as a reference for the future optimization of systems based on the multi-hole combined external rotary bit technology.展开更多
Purpose:To evaluate the anatomical and visual outcomes of pars plana vitrectomy (PPV) with internal limiting membrane (ILM).peeling and use of retinal tamponade for retinal detachments resulting from macular hole (MHR...Purpose:To evaluate the anatomical and visual outcomes of pars plana vitrectomy (PPV) with internal limiting membrane (ILM).peeling and use of retinal tamponade for retinal detachments resulting from macular hole (MHRD) in highly myopic eyes. Methods:.Twenty-nine highly myopic patients.(29 eyes) underwent PPV with ILM peeling and retinal tamponade for MHRD were enrolled. Demographics and best-corrected visual acuity.(BCVA).were measured preoperatively and at final follow-up. Anatomical success and macular hole closure were analyzed. Results:.Patients' mean age of patients was 58.7±10.6 years, mean follow-up was 11.7±7.4 months. Twenty three eyes (23/26,88.5%)undergoing primary PPV combined with ILM peeling had successful initial retinal reattachment, including 19 eyes (19/19, 100%) with silicone oil tamponade and in 4 eyes (4/7,57.1%).with sulfur hexafluoride.(C3F8).tamponade. Overall anatomical success was achieved in 27 eyes (27/29, 93.1%)..The macular hole closure was observed in 17 eyes (17/26, 65.4%) with final anatomical success. Compared to preoperative BCVA,.the mean postoperative BCVA in the eyes with anatomical success was significantly improved (P = 0.007, Wilcoxon signed rank test). Conclusion:.As a primary or secondary procedure,.PPV combined with ILM peeling and usage of retinal tamponade serves as an effective method for MHRD in highly myopic eyes.展开更多
Purpose: To evaluate the efficacy of vitrectomy with peripapillary photocoagulation and silicone oil tamponade for the proliferative retinal detachment associated with macular hole in children with morning glory syndr...Purpose: To evaluate the efficacy of vitrectomy with peripapillary photocoagulation and silicone oil tamponade for the proliferative retinal detachment associated with macular hole in children with morning glory syndrome. Methods: Eight children with morning glory syndrome (mean age 8.0±2.8 years; range 5~13 years) were included; all patients had unilateral eye disease and were initially misdiagnosed as having bilateral squint or amblyopia, with best corrected visual acuity <6/60. Five patients could not cooperate with the fundus examination and one patient had lens opacities.B-ultrasound confirmed that all eight patients had retinal detachment and optic disc dysplasia.All patients underwent standard 3-port pars plana vitrectomy surgery . (20G for three cases and 23G for five cases).At surgery,all patients were confirmed to have morning glory syndrome,macular hole, and proliferative retinal detachment;.two cases had a funnel shaped bulge. All the retinal detachments involved the macular area, and macular hole was detected in the abnormal expansion excavation of the optic disk. The epiretinal membrane and subretinal membrane were completely removed during surgery. Combined photocoagulation in the abnormal expansion excavation of the optic disk, and silicone oil tamponade were also performed. Results:All eyes achieved anatomical resolution of retinal detachment.After follow-ups ranging from eight months to four years,the visual function for all patients was improved by postoperative refractive correction associated with vision training. Best corrected visual acuity was 6/600 to 6/30 at the final follow-up, no retinal detachment recurred, and no silicone oil fluid entered the subretinal space. The silicone oil was successfully removed postoperatively after a mean of 1.5 years. Conclusion:Vitrectomy with peripapillary photocoagulation and silicone oil tamponade is effective in treating the proliferative retinal detachment associated with macular hole in children with morning glory syndrome. (Eye Science 2013;28:7-10)展开更多
AIM:To study the vitreo-retinal interface and macular changes on optical coherence tomography(OCT) in the fellow eyes of patients with macular hole.·METHODS:Patients with idiopathic macular hole in one or both ey...AIM:To study the vitreo-retinal interface and macular changes on optical coherence tomography(OCT) in the fellow eyes of patients with macular hole.·METHODS:Patients with idiopathic macular hole in one or both eyes presented to our institute between January 2003 and December 2009 were evaluated retrospectively.Demographic details,best-corrected visual acuity and vitreo-retinal interface,and macular changes of the fellow eye on OCT were studied.·RESULTS:Seventy patients underwent OCT of both eyes during the study period.The average age group was 61.96 years and 35(50%) were females.Among the fellow eyes,normal foveal contour was noted in 36(51.4%) eyes and 34(48.6%) eyes were observed to have vitreo-retinal interface changes.Of them,13(18.6%) eyes had some stage of full thickness macular hole and 21(30.0%) eyes had interface changes.There was no statistical correlation between involved eye lesions(P =0.64) or visual acuity(P =0.55) as predictors of development of either fellow eye lesions or poor visual acuity.·CONCLUSION:There is a significant chance of having vitreo-retinal interface findings in the fellow eyes of patients presenting with macular hole.OCT should be considered in both eyes of patients with macular hole to detect early changes in the fellow eyes,which may require an early intervention.展开更多
基金supported by National Nature Science Foundation of China (NO.81170863)
文摘Background: The purpose is to investigate the relationship between full-thickness macular hole(MH) and retinal break(RB) and/or lattice degeneration.Methods: Patients diagnosed as full-thickness MH and referred to Dr. Lin Lu from January 2009 to December 2013 were evaluated. All patients underwent general ophthalmologic examinations, fundus examination and optical coherence tomography(OCT). The RB and/or lattice degeneration were recorded.Results: Totally 183 eyes of 167 patients were included. The sex ratio of men to women was 1:2.88. A total of 17 eyes were pseudophakic and 166 eyes were phakic. RB and/or lattice degeneration were found in 62 eyes(33.88%). The prevalence of RB and/or lattice degeneration was similar between men and women(P=0.344>0.05). There was no statistical difference between the pseudophakic eyes and phakic eyes(P=0.138>0.05). All of the RB and/or lattice degeneration were located near or anterior to the equator. The inferior quadrants and the vertical meridian were af ected more often than the superior quadrants and the horizontal meridian.Conclusions: We identified a high incidence of RB/lattice degeneration in cases of full-thickness MH. Carefully examination of the peripheral retina and prophylactic treatment of RB and/or lattice degeneration are critical.
基金supported by the Health Bureau of Zhejiang Province, China (No.20100580)
文摘AIM: To investigate the efficacy of non-buckled vitrectomy with classical endotamponade agents in the treatment of primary retinal detachment (RD) complicated by inferior breaks and proliferative vitreoretinophathy (PVR). METHODS: A retrospective, consecutive and case series study of 40 patients with inferior break RD and PVR >= C1 was conducted. All patients underwent a standard 3-port 20-gauge pars plana vitrectomy (PPV) with gas or silicone oil tamponade without supplementary scleral buckling. The vitreous and all proliferative membrane were completely removed, and retinectomy was performed when necessary. The mean follow-up was 12.5 months. The primary and final anatomic success rate, visual acuity and complications were recorded and analyzed. RESULTS: Primary anatomic success rate was achieved in 35 of 40 eyes (87.5%) and the final anatomic success rate was 100%. The most common cause of redetachment was recurrent PVR. The best-corrected visual acuity (BCVA) at final follow-up was improved in 34 eyes (85%), remained stable in 1 eye (2.5%), and worsened in 5 eyes (12.5%). The mean visual acuity at final follow-up was improved significantly (P=0.000). CONCLUSION: This retrospective study provides evidence that vitrectomy without scleral buckling seemed to be an effective treatment for inferior break RD with PVR. With complete removal of vitreous and proliferative membranes and timing of retinectomy, the inferior breaks which complicated with PVR could be dosed successfully without additional sclera! buckling.
文摘AIM:To compare success rates and complications of Densiron 68 and 1000cSt silicone oil (SO) in the management of rhegmatogenous retinal detachment (RRD) with inferior breaks (IBs). METHODS:Totally 61 eyes of 61 consecutive patients with RRD with IBs were assigned to pars plana vitrectomy (PPV) with Densiron (n =31) or PPV with SO (n=30) in order of presentation. SO and Densiron removal was performed 3 months after initial surgery. Follow up visits were terminated 6 months after SO removal. ·RESULTS:With a single operation, the Densiron group showed 84% and SO 74% reattachment. With further surgery, both groups showed 90% reattachment. Complications such as cataract, raised intraocular pressure (IOP), inflammatory reaction, macular epiretinal membranes, and emulsification of SO were seen in both groups. CONCLUSION:Densiron and SO are found to have similar success rates and complications.
文摘AIM:To assess the efficacy and safety of parafoveal retinal massage combined with autologous whole blood cover in the treatment of refractory macular holes(MHs)and present the surgical procedure.METHODS:Patients with giant(minimum diameter>800 pm),recurrent or persistent MHs who underwent PPV combined with parafoveal retinal massage and autologous whole blood cover using C3F8 as tamponade agent from February 2018 to May 2019 were enrolled in this retrospective study.After surgery,all patients were informed to maintain a prone position for at least 7d.Preoperative and postoperative best-corrected visual acuities(BCVAs)were compared and MH closure rate was measured as the main outcome.RESULTS:A total of 13 MH patients consisted of 6 giant MHs,4 persistent holes and 3 recurrent holes(5 men and 8 women;average age was 56.40±11.72y)were enrolled in this study.MH closure was achieved in 11 eyes by this modified surgical technique while 2 eyes failed.Revitrectomy with autologous neurosensory retinal patch transplantations was applied for those 2 patients and then both holes were closed.No intraoperative complications were observed.BCVA improved from 1.73 IogMAR to 0.74 IogMAR at 6mo postoperation.There was significant difference in BCVA before versus after the surgery(P<0.05).There were no adverse events occurred during the follow-up period.CONCLUSION:With easier surgical procedure,parafoveal retinal massage combined with autologous whole blood cover is an effective addition to the surgical options for the management of refractory MHs.
基金supported by the National Natural Science Foundation of China(No.52174004 and No.51804318)the National Key Research and Development Program of China(No.2018YFC0808401)
文摘The use of mechanical drilling in accessing energy resources stored in deep and hard rock formations is becoming increasingly challenging.Thus,laser irradiation has emerged as a novel drilling method with considerable in this context.This study examines the variation of rock fracture length,fracture tortuosity,hole size,and rock breaking efficiency for a different number of holes and laser power,based on the constant total energy of laser irradiation.As indicated by the results,increasing the laser power increases the laser intensity,which helps increase the hole diameter and depth.Moreover,for the same laser power,increasing the number of irradiated holes reduces the laser energy absorbed by each hole,which is not conducive to increasing the hole depth.As the number of holes increases,the mass loss of the rock also increases,while both specific energy(SE)and modified specific energy(MSE)decrease.When the number of holes remains the same,the mass of the shale removed by low power is less than that removed by high power,while SE and MSE have an inverse relation with power.Therefore,high laser power and multiple-hole irradiation are more conducive to rock breaking.Besides,the fracture length and fracture tortuosity of the rock irradiated by the low laser power will increase first and then decrease with the increase in the number of holes,and reach the peak value when the irradiation takes place through three holes.When a high-power laser irradiates the rock,the fracture length and tortuosity will increase with the increase in the number of irradiation holes.This is because a rock irradiated by low power dissipates more energy,with the result that the energy absorbed by the sample with four irradiation holes is not enough to break the rock quickly.This study is expected to provide some guidance to break rock for drilling deep reservoirs and hard rock formations using laser irradiation.
文摘AIM: To evaluate anatomical and visual outcomes of episcleral macular buckling (EMB) for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole.METHODS: Five cases of EMB for initial failure of retinal reattachment after internal limiting membrane (ILM) peeling and silicone oil tamponade caused by myopic macular hole were retrospectively reviewed. A silicone sponge sutured directly across the macular region was performed on the silicone oil filled eyes. Silicone oil was removed no sooner than 1 month post- EMB. The duration of follow -up time after removal of silicone oil was more than 3 months.RESULTS: Retinas of five eyes were all reattached at the last follow-up. The postoperative vision ranged from counting fingers to 0.08.CONCLUSION: Anatomical results improved after EBM for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole, which was not evident for visual outcome.
基金Medical Research Project of Sichuan Province(No.S20018)。
文摘AIM:To evaluate the therapeutic effect of amniotic membrane(AM)for covering high myopic macular hole associated with retinal detachment following failed primary surgery.METHODS:Seventeen eyes of 17 patients whose axial length was more than 29 mm suffered from macular hole(MH)or MH associated with retinal detachment(RD),and had previously surgery of pars plana vitrectomy(PPV)with internal limiting membrane(ILM)peeling and silicone oil(SO)tamponade.Half a year after the surgery,optical coherence tomography(OCT)showed that MH did not heal in all 17 eyes and RD was still maintained in 13 eyes of these 17 eyes.We performed SO removal combined with AM covering on macular area and C3 F8 tamponade,and phacoemulsification combined with intraocular lens implantation simultaneously cataract eyes.We followed up these patients for one year.RESULTS:In all 17 eyes,SO was removed successfully,MHs were healed and RDs were reattached.One eye(5.89%,1/17)had AM shifted half a month after surgery and underwent a second surgery to adjust the position of the AM and supplement C3 F8.After surgery,the visual acuity(VA)improved in 15 eyes(88.24%,15/17),no change in two eyes(11.76%,2/17).No serious complications occurred in all eyes.CONCLUSION:AM covering is helpful to rescue the previous failure surgery of high myopic MH.
文摘AIM: To evaluate the causes and associations of missed retinal breaks(MRBs) and posterior vitreous detachment(PVD) in patients with rhegmatogenous retinal detachment(RRD).METHODS: Case sheets of patients undergoing vitreo retinal surgery for RRD at a tertiary eye care centre were evaluated retrospectively. Out of the 378 records screened, 253 were included for analysis of MRBs and191 patients were included for analysis of PVD,depending on the inclusion criteria. Features of RRD and retinal breaks noted on examination were compared to the status of MRBs and PVD detected during surgery for possible associations.RESULTS: Overall, 27% patients had MRBs. Retinal holes were commonly missed in patients with lattice degeneration while missed retinal tears were associated with presence of complete PVD. Patients operated for cataract surgery were significantly associated with MRBs(P =0.033) with the odds of missing a retinal break being1.91 as compared to patients with natural lens. Advanced proliferative vitreo retinopathy(PVR) and retinal bullae were the most common reasons for missing a retinal break during examination. PVD was present in 52% of the cases and was wrongly assessed in 16%. Retinal bullae,pseudophakia/aphakia, myopia, and horse shoe retinal tears were strongly associated with presence of PVD.Traumatic RRDs were rarely associated with PVD. CONCLUSION: Pseudophakic patients, and patients with retinal bullae or advanced PVR should be carefully screened for MRBs. Though Weiss ring is a good indicator of PVD, it may still be over diagnosed in some cases. PVD is associated with retinal bullae and pseudophakia, and inversely with traumatic RRD.
基金Supported by the Project of Integrated Traditional Chinese and Western Medicine by Tianjin Municipal Health Commission(No.2021067)。
文摘AIM: To observe the clinical effect of pars plana vitrectomy(PPV) and silicone oil filling surgery combined with intraoperative posterior scleral staphyloma(PS) marginal retinal photocoagulation in the treatment of high myopic macular hole retinal detachment(MHRD) with PS.METHODS: This was a retrospective clinical study. From May 2017 to March 2020, 62 MHRD patients with PS(62 eyes) were enrolled in the study. Patients were divided into 23 G PPV combined with PS marginal retina intraoperative photocoagulation group(combined group) and conventional surgery group(conventional group), with 31 eyes in each. Triamcinolone acetonide and indocyanine green were used to remove the epiretinal membrane and the posterior macular inner limiting membrane(ILM). In the combined group, 2 to 3 rows of retinal photocoagulation were performed on the edge of the PS. The patients were followed up for an average of 8.34±3.21 mo. The first retinal reattachment rate, macular hole closure rate, Duration of silicone oil tamponade, best corrected visual acuity(BCVA) and average number of operations were observed and compared between the two groups.RESULTS: The first retinal reattachment rates of the eyes in the combined group and the conventional group were 96.7%(29/31) and 67.7%(21/31), respectively(χ~2=6.613, P=0.010). The macular hole closure rates in the combined group and the conventional group were 74.2%(23/31) and 67.7%(21/31), respectively(χ~2=0.128, P=0.721). The Duration of silicone oil tamponade of the patients in the combined group was lower than that of the routine group(t=-41.962, P≤0.001). Postoperative log MAR BCVA values of patients in the combined group and the conventional group were 1.27±0.12 and 1.26±0.11, compared with the log MAR BCVA before surgery, each group was improved(t=19.947, t=-19.517, P≤0.001, P≤0.001). There was no significant difference in the log MAR BCVA between the eyes of the two groups(t=-0.394, P=0.695). The average numbers of operations on the eyes in the conventional group and the combined group were 2.39±0.62 and 2.06±0.25 times, the combined group had fewer operations on average(t=-2.705, P=0.009). CONCLUSION: Intraoperative PPV treatment of MHRD with PS combined with PS marginal endolaser photocoagulation can effectively increase the rate of retinal reattachment after the first operation, reduce the number of repeated operations, and reduce the postoperative duration of silicone oil tamponade.
基金the Science and Technology Innovation and Entrepreneurship Fund of China Coal Technology Engineering Group(2019-TD-QN038,2019-TDQN017)Enterprise Independent Innovation Guidance Project(2018ZDXM05,2019YBXM30).
文摘The characteristics of the flow field associated with a multi-hole combined external rotary bit have been studied by means of numerical simulation in the framework of an RNG k-εturbulence model,and compared with the results of dedicated rock breaking drilling experiments.The numerical results show that the nozzle velocity and dynamic pressure of the nozzle decrease with an increase in the jet distance,and the axial velocity of the nozzle decays regularly with an increase in the dimensionless jet distance.Moreover,the axial velocity related to the nozzle with inclination angle 20°and 30°can produce a higher hole depth,while the radial velocity of the nozzle with 60°inclination can enlarge the hole diameter.The outcomes of the CFD simulations are consistent with the actual dynamic rock breaking and pore forming process,which lends credence to the present results and indicates that they could be used as a reference for the future optimization of systems based on the multi-hole combined external rotary bit technology.
文摘Purpose:To evaluate the anatomical and visual outcomes of pars plana vitrectomy (PPV) with internal limiting membrane (ILM).peeling and use of retinal tamponade for retinal detachments resulting from macular hole (MHRD) in highly myopic eyes. Methods:.Twenty-nine highly myopic patients.(29 eyes) underwent PPV with ILM peeling and retinal tamponade for MHRD were enrolled. Demographics and best-corrected visual acuity.(BCVA).were measured preoperatively and at final follow-up. Anatomical success and macular hole closure were analyzed. Results:.Patients' mean age of patients was 58.7±10.6 years, mean follow-up was 11.7±7.4 months. Twenty three eyes (23/26,88.5%)undergoing primary PPV combined with ILM peeling had successful initial retinal reattachment, including 19 eyes (19/19, 100%) with silicone oil tamponade and in 4 eyes (4/7,57.1%).with sulfur hexafluoride.(C3F8).tamponade. Overall anatomical success was achieved in 27 eyes (27/29, 93.1%)..The macular hole closure was observed in 17 eyes (17/26, 65.4%) with final anatomical success. Compared to preoperative BCVA,.the mean postoperative BCVA in the eyes with anatomical success was significantly improved (P = 0.007, Wilcoxon signed rank test). Conclusion:.As a primary or secondary procedure,.PPV combined with ILM peeling and usage of retinal tamponade serves as an effective method for MHRD in highly myopic eyes.
文摘Purpose: To evaluate the efficacy of vitrectomy with peripapillary photocoagulation and silicone oil tamponade for the proliferative retinal detachment associated with macular hole in children with morning glory syndrome. Methods: Eight children with morning glory syndrome (mean age 8.0±2.8 years; range 5~13 years) were included; all patients had unilateral eye disease and were initially misdiagnosed as having bilateral squint or amblyopia, with best corrected visual acuity <6/60. Five patients could not cooperate with the fundus examination and one patient had lens opacities.B-ultrasound confirmed that all eight patients had retinal detachment and optic disc dysplasia.All patients underwent standard 3-port pars plana vitrectomy surgery . (20G for three cases and 23G for five cases).At surgery,all patients were confirmed to have morning glory syndrome,macular hole, and proliferative retinal detachment;.two cases had a funnel shaped bulge. All the retinal detachments involved the macular area, and macular hole was detected in the abnormal expansion excavation of the optic disk. The epiretinal membrane and subretinal membrane were completely removed during surgery. Combined photocoagulation in the abnormal expansion excavation of the optic disk, and silicone oil tamponade were also performed. Results:All eyes achieved anatomical resolution of retinal detachment.After follow-ups ranging from eight months to four years,the visual function for all patients was improved by postoperative refractive correction associated with vision training. Best corrected visual acuity was 6/600 to 6/30 at the final follow-up, no retinal detachment recurred, and no silicone oil fluid entered the subretinal space. The silicone oil was successfully removed postoperatively after a mean of 1.5 years. Conclusion:Vitrectomy with peripapillary photocoagulation and silicone oil tamponade is effective in treating the proliferative retinal detachment associated with macular hole in children with morning glory syndrome. (Eye Science 2013;28:7-10)
文摘AIM:To study the vitreo-retinal interface and macular changes on optical coherence tomography(OCT) in the fellow eyes of patients with macular hole.·METHODS:Patients with idiopathic macular hole in one or both eyes presented to our institute between January 2003 and December 2009 were evaluated retrospectively.Demographic details,best-corrected visual acuity and vitreo-retinal interface,and macular changes of the fellow eye on OCT were studied.·RESULTS:Seventy patients underwent OCT of both eyes during the study period.The average age group was 61.96 years and 35(50%) were females.Among the fellow eyes,normal foveal contour was noted in 36(51.4%) eyes and 34(48.6%) eyes were observed to have vitreo-retinal interface changes.Of them,13(18.6%) eyes had some stage of full thickness macular hole and 21(30.0%) eyes had interface changes.There was no statistical correlation between involved eye lesions(P =0.64) or visual acuity(P =0.55) as predictors of development of either fellow eye lesions or poor visual acuity.·CONCLUSION:There is a significant chance of having vitreo-retinal interface findings in the fellow eyes of patients presenting with macular hole.OCT should be considered in both eyes of patients with macular hole to detect early changes in the fellow eyes,which may require an early intervention.