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"AIM: To investigate the depressive state among the patients with symptomatic vitreous floaters (SVF), as well as its change after SVF removal via vitrectomy surgery. METHODS: Twenty-eight eyes of 28 patients who underwent 27-gauge pars plana vitrectomy (PPV) for SVF were included. Thirty-nine eyes of 39 age- and gender- matched healthy volunteers without SVF were also recruited as a healthy control. Center for Epidemiologic Studies Depression (CES-D) was used to assess volunteers and patients’ depression (before and 1wk after PPV). RESULTS: The CES-D score was 18.3±8.6 for patients, and was 12.4±6.0 for healthy control (P=0.003). Patients were significantly more likely to be in a depressive state (53.6%, defined as CES-D score ≥16) than the healthy control (20.5%, P=0.005). For patients with SVF, the CES-D score was negatively correlated with their age (rs=-0.42, P=0.025). After PPV, both the CES-D score (11.9±5.4 vs 18.3±8.6, P

We performed a systematic review and meta-analysis to assess the role of prophylactic laser retinopexy in preventing rhegmatogenous retinal detachment (RRD) in acute retinal necrosis (ARN).Pubmed, Embase and Cochrane databases were searched for eligible studies from inception to July 2020. Comprehensive clinical demographics were extracted from each study by two independent investigators. A random effects model was selected to analyze the OR of RRD risk and visual outcome with 95%CI. Subsequent subgroup and sensitivity analysis were conducted to evaluate the source of heterogeneity.A total of eight studies and 247 eyes (111 prophylactic laser retinopexy eyes and 136 eyes receiving antiviral treatment) were included in this analysis. There was moderate statistical heterogeneity across all studies. When compared with routine antiviral treatment alone, RRD risk decreased in patients receiving prophylactic laser retinopexy, however, this was not statistically significant (P = 0.09, OR = 0.42, 95%CI: 0.15-1.15). There was significant improvement in BCVA during the follow-up period in the prophylactic laser retinopexy subgroup (P = 0.01, WMD = - 0.98, 95%CI: - 1.74, - 0.22).Based on current analysis, our results did not support convincing evidence of prophylactic laser in preventing RRD. Future studies featuring high-quality, multicenter trials will be required to correct baseline characteristics.This meta-analysis has been retrospectively registered in Prospero (registration number: CRD42020201008).

Durability of photocatalytic coatings is a major concern in engineering practice. Here, two types of novel visible light-responsive coatings, both consisting of vinyl chloride/vinyl ester/ethylene copolymer (as a binder) and graphitic carbon nitride (g-C3N4) but different in fabrication, are proposed and applied on the mortar surface. The first type is mono-layer coating (MC), where the g-C3N4 suspension containing the binder is directly sprayed on the mortar. The second type is double-layer coating (DC), where the binder layer is applied on mortar surface before spraying the g-C3N4 layer. Results show that the binder addition leads to a good anchorage of the coatings on both MC and DC mortar substrates, along with desirable resistance to peeling and washing, compared to the g-C3N4 coated mortar without the binder. The well-distributed binder in g-C3N4-based coating inevitably decreases the photocatalytic efficiency of the MC mortar due to masking effect of the binder on the coating surface. The DC mortar, on the contrary, takes full advantage of the binder adhesion by inserting a binder layer and therefore holds strong resistance to peeling and washing without compromising its photocatalytic efficiency. The proposed DC technique provides a promising strategy to fabricate highly cost-effective and durable photocatalytic coatings applied on cementitious materials.

Background：Vitrectomy and membrane peeling followed by gas filling technique has become a standard procedure of macular hole surgery, the outcomes are affected by many factors, and which kind of intraocular tamponade is the best choice still has some conflicts. The purpose of this study is to investigate whether air filling can achieve comparable effects to long-acting inert gases when different macular hole sizes are enrolled. Methods：116 patients with idiopathic macular hole were enrolled in this retrospective study, 44 received C3F8 tamponade and 72 received sterile air tamponade. Before and after vitrectomy surgery, the best corrected visual acuity, slit lamp examination, fundus examination and intraocular pressure were analyzed. Results：No statistically significant difference was fund in age, gender, axial length, intraocular pressure, or preoperative visual acuity between groups. After the surgery, the closure rates of air group and C3F8 group with macular hole diameter ≤400 microns were 94.4% and 100.0%, with no significant difference between the two groups (P = 0.701). The closure rates of macular hole diameters lager than 400 microns are 66.7% and 91.3%, P = 0.029. The total closure rates of the two groups are 80% and 95.6%, P =0.018. Conclusions：In idiopathic macular hole surgery, the effect of air as an intraocular tamponade material is similar to that of C3F8 in macular hole with diameters less than 400 microns. In patients with larger macular hole (diameter over 400 microns) performed therapeutic surgery with air filling, internal limiting membrane insertion or flap inversion may be recommended get better outcomes.

Purpose: Traditionally acceptable methods of anesthesia for vitrectomy surgery are quite varied. However, each of these methods has its own potential for complications that can range from minor to severe. The surgery procedure of vitrectomy for symptomatic vitreous floaters is much simpler, mainly reflecting in the nonuse of sclera indentation, photocoagulation, and the apparently short surgery duration. The use of 27-gauge cannulae makes the puncture of the sclera minimally invasive. Hence, retrobulbar anesthesia, due to its rare but severe complications, seemed excessive for this kind of surgery. Method: Three cases of 27-gauge, sutureless pars plana vitrectomy for symptomatic vitreous floaters with topical anesthesia are reported. Results: The vitrectomy surgeries were successfully performed with topical anesthesia (proparacaine, 0.5%) without operative or postoperative complications. Furthermore, none of the patients experienced apparent pain during or after the surgery. Conclusion: Topical anesthesia can be considered for 27-guage vitrectomy in patients with symptomatic vitreous floaters.

Purpose: To report a case of Staphylococcus epidermidis endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. Methods: The clinical course and imaging findings, including fundus optomap, and spectral domain optical coherence tomography of a 24-year-old male patient were documented. Results: The patient, with a preoperative best-corrected visual acuity (BCVA) of 1.0, developed endophthalmitis following 27-gauge pars plana vitrectomy for symptomatic vitreous floaters. After a series of treatments, including emergent vitreous tap and silicone oil injection, antibiotic treatment, and silicone oil removal, the patient regained a BCVA of 0.6. Conclusion: Although rare, the potential risk of endophthalmitis should be explicitly discussed with patients considering surgical intervention for vitreous floaters.

To compare the anatomical and functional outcomes of the inverted internal limiting membrane (ILM) flap technique and the autologous blood clot (ABC) to ILM insertion technique for the repair of refractory macular hole (RMH). Fifty-two consecutive patients (52 eyes) diagnosed with RMH with a minimum diameter more than 700 µm were enrolled. All patients underwent vitrectomy and gas tamponade. Of these, 25 patients undergo inverted ILM flap combination with ABC (Group A). The remaining 27 patients underwent ILM insertion (Group B). The main outcome measures were macular hole (MH) closure, foveal configuration, logarithm of the minimum angle of resolution (logMAR), best-corrected visual acuity (BCVA), superficial foveal avascular zone (FAZ) and superficial parafoveal vessel density. Three months post-operation, MH was successfully anatomic closed in 24 of 25 eyes (96%) in Group A and 25 of 27 eyes (92.5%) in Group B (P = 0.599). A concave foveal configuration of MH closure was observed in 23 of 25 eyes (92%) in Group A and 2 of 27 eyes (7.4%) in Group B (P

AIM: To report the results of rhegmatogenous retinal detachment (RRD) repair after pars plana vitrectomy (PPV) without operative use of heavy liquid, and utilizing air tamponade in selected cases. METHODS: RRD patients without severity of proliferative vitreoretinopathy C2 or more underwent PPV without operative use of heavy liquid, and utilizing air tamponade were consecutively enrolled. Alternative postoperative facedown position or lateral position was required for 3-5d. RESULTS: Totally 36 eyes of 36 patients (24 males, 66.7%) aged 53.8±10.9y underwent this modified surgery. The mean number of retinal break was 2.1±1.3. Most of the eyes (29, 80.6%) had retinal detachment involving more than one quadrant. Twenty-two (61.1%) eyes with cataract had combined phacoemulsification and intraocular lens implantation. The mean follow up time was 4.6±1.8mo. Two eyes with retinal redetachment underwent a second retinal repair surgery with silicone oil tamponade, yielding the primary reattachment rate to 94.4% (34/36). Six (16.7%) eyes had intraocular pressure higher than 25 mm Hg. The visual acuity (logMAR) improved from 0.98±0.74 preoperatively to 0.52±0.31 postoperatively (P

The purpose of this study was to compare the silicone oil removal rate between vitrectomy and manual syringe negative pressure approach. Thirty-five silicone oil-filled eyes were enrolled and allocated for manual (n = 19) and vitrectomy (n = 16) removal approaches. For manual approach, a 10-ml syringe was connected to the 23-gauge cannula through a short section of blood transfusion tube. Removal was started after pulling and fixing the plunger to the end part. The syringe was pulled away immediately once the residual of silicone oil cannot be observed through the cornea. For vitrectomy approach, the only difference was the source of negative pressure, i.e., the blood transfusion tube was connected to the cannula directly to remove the silicone oil. Silicone oil removal rate was defined as the volume of silicone oil divided by the time taken for removal. The mean time taken for silicone oil removal was faster for manual approach than vitrectomy approach (4.13 ± 1.41 vs. 6.14 ± 1.49, p = 0.001). Furthermore, the silicone oil removal rate was larger for manual approach (1.42 ± 0.30 vs. 0.90 ± 0.16 ml/min, p

Background To compare the safety and efficacy of topical anesthesia versus retrobulbar anesthesia in 27-gauge pars plana vitrectomy (PPV) for vitreous floaters. Methods 30 patients with vitreous floaters were randomized into Group T (topical anesthesia, proparacaine eye drop) and Group R (retrobulbar anesthesia), and underwent 27-gauge PPV. A 5-point visual analogue pain scale (VAPS) was used to assess patients’ pain experience of anesthesia and surgery procedure (during surgery, 2 h and 1 day after surgery). Results The VAPS of anesthesia procedure was 1.27 ± 0.59 for patients in Group R, while it was all 0 for patients in Group T (p

Background Endophthalmitis is a rare but severe complication following PPV. The incidence of endophthalmitis varies between 20-gauge, 23-gauge, and 25-gauge incisions. The incidence and clinical features of endophthalmitis after 23-gauge PPV in an eye hospital in China was reported in this study. Methods Data of the eyes that underwent 23-gauge PPV from January 2011 to December 2014 at the Eye Hospital of Wenzhou Medical University was retrospectively collected. All the information was obtained from the electronic medical system. The exclusion criteria included: (1) preoperative diagnosis of endophthalmitis; (2) history of vitrectomy; (3) intraocular surgery within 6 months; (4) history of ocular penetrating trauma; (5) sutures for any of the 3 sclerotomy incisions; (6) patients with cancer, acquired immune deficiency syndrome, or taking drugs that may influence the immune system. The diagnosis of endophthalmitis was based on clinical characteristics and/or culture results from an operative sample. Results Three thousand nine hundred seventy nine eyes that underwent 23-gauge PPV surgery were included in this study. Among these eyes, 3 eyes developed endophthalmitis after surgery, giving an incidence of 0.075% (3/3979). The period in which endophthalmitis developed ranged from 1 to 5 days post-operation. The visual acuity decreased to hand motions or light perception postoperatively. The culture of aqueous and vitreous of the 2 eyes revealed Staphylococcus epidermidis and enterococcus faecalis respectively, however was negative for the third eye. All 3 eyes had a favorable response to the treatment of vitreous tap and intravitreal antibiotics injection. Two eyes gained visual acuity of 0.05 and 0.5, respectively at the final visit. Conclusions Endophthalmitis is a rare but sight-threatening complication after 23-gauge pars plana vitrectomy. The peak duration of onset was within 5 days post-operation, with gram positive cocci being the common pathogenic organism. Electronic supplementary material The online version of this article (10.1186/s12886-018-0678-5) contains supplementary material, which is available to authorized users.

Purpose. To report a new technique for sutureless intrascleral fixation of three-piece foldable intraocular lenses (IOLs) using 25-gauge trocars. Methods. We performed this technique on patients with insufficient posterior capsule support. Seventeen eyes from 15 patients with aphakia, dislocated IOL, or subluxated crystalline lens undergoing posterior chamber sutureless implantation of an IOL were studied. The haptics of the IOL were externalized using two 25-gauge forceps. The haptics were bended back (hook-like) into the vitreous cavity through a scleral incision made by using a 25-gauge trocar. And, IOL tilt was determined by using a slit lamp and UBM, and complications were recorded. Results. The IOLs were fixed with exact centration and axial stability. No wound leakage was reported even without the use of sutures. The mean best-corrected visual acuity (BCVA) was 0.82 logarithm of the minimum angle of resolution (logMAR) units preoperatively, and the mean BCVA was 0.44 logMAR units at the 6-month follow-up visit. No postoperative retinal detachment, endophthalmitis, IOL tilt or dislocation, or vitreous hemorrhage was noted. Conclusion. Sutureless intrascleral haptic-hook posterior chamber IOL implantation using 25-gauge trocars provides good IOL fixation with reliable wound closure without the use of sutures. This trial is registered with ChiCTR1800017436.

Purpose.To report the safety and efficacy of adjustable postoperative position for rhegmatogenous retinal detachment (RRD).Methods.Retrospective review of 536 consecutive RRD eyes that underwent vitrectomy surgery for retina repair from year 2008 to 2014. The retinal breaks were divided into superior, lateral (nasal, temporal, and macular), and inferior locations, according to the clock of breaks. Patients with superior and lateral break location were allowed to have facedown position or lateral decubitus position postoperatively, while patients with inferior break location were allowed to have facedown position.Results.403 eyes of 400 patients were included. The mean follow-up interval was 22.7 ± 21.3 months. The overall primary retinal reattachment rate was 93.3%. There were 24 (6.0%), 273 (67.7%), and 106 (26.3%) patients with superior, lateral, and inferior break location, respectively. The primary reattachment rate was 95.8%, 92.3%, and 95.3% accordingly. After further divided the break location into subgroups as a function of duration of symptom, postoperative lens situation, number of retinal breaks, and different vitreous tamponade, the primary reattachment rates were all higher than 82%.Conclusion.Adjustable postoperative positioning is effective and safe for RRD repair with different break locations. Choosing postoperative position appropriately according to retinal break locations could be recommended.

Purpose.To investigate the effect of menstrual cycle on perioperative bleeding of primary vitreoretinal surgery.Methods.Data on female patients who had vitrectomy surgery was retrospectively collected. Exclusion criteria were history of trauma, vitreous hemorrhage, previous vitreoretinal surgery, diabetic retinopathy, endophthalmitis, acute retinal necrosis, single vitreous opacity, and use of antiplatelet agents. Perioperative bleeding was defined as hemorrhage in the iris, vitreous, choroidal, retina, or subretina during surgery or up to one day postoperatively. 69 patients had surgery during the perimenstrual phase (group M, days 1–7 and days 21–28) and 86 during periovulatory phase (group O, days 8–20) were enrolled.Results.The proportion of operative bleeding in group M (14.5%) and group O (10.5%) was not found to be significantly different (p=0.45). No postoperative bleeding was recorded in both groups. The univariate odds ratio (OR) and 95% confidence interval (CI) of perimenstrual phase for operative bleeding were 0.69 (0.26–1.81). After adjusting for patients’ age, vitreoretinal diseases, and surgeons, the multivariate OR and 95% CI were 0.71 (0.27–1.86).Conclusion.This study suggests that the timing of the menstrual period does not affect perioperative bleeding for primary vitreoretinal surgery. Menstruation appears not to be a contraindication for vitreoretinal surgery.

Purpose. To report the surgical outcomes of 27-gauge pars plana vitrectomy (PPV) for symptomatic vitreous floaters.Methods. 47 eyes of 47 patients (39 males, 83.0%) with symptomatic vitreous floaters who underwent 27-gauge PPV and followed up for more than 6 months were included. The mean age was 34.7 ± 13.5 years.Results. No operative complication occurred. At first day postoperatively, the intraocular pressure (IOP) was significantly lower than that at other time points (8.6 ± 2.7 mmHg,p<0.001). 28 (59.6%) eyes had transient hypotony (IOP Conclusion. Visual acuity of most patients remained unchanged or improved following 27-gague pars plana vitrectomy for symptomatic vitreous floaters, resulting in high patient satisfaction. However, this treatment should be performed with great caution since severe postoperative complications may still occur. This trial is registered withNCT03049163.

Purpose To report a case of acute primary angle closure that developed in the fellow eye rapidly after facedown position after vitrectomy surgery. Patients and methods A 66-year-old female developed acute primary angle closure in the fellow eye approximately 1.5 hours after facedown position after vitrectomy surgery for macular hole. Results The intraocular pressure was controlled after treatment that included halting the facedown position, intravenous mannitol injection, and topical pilocarpine instillation. Facedown position was continued after laser peripheral iridotomy was performed. The intraocular pressure was controlled within normal range even after pilocarpine was withdrawn. Conclusions Although rare, the potential risk of acute-angle closure should be explicitly explained to patients being considered for facedown position after vitrectomy. Prophylactic intervention, such as laser peripheral iridotomy, could be considered for anatomically predisposed eyes.

Purpose:To assess the success rates and complications of Densiron 68 intraocular tamponade in the management of complicated retinal detachment (RD) with proliferative vitreoretinopathy (PVR). Methods:Twenty-one eyes of 20 patients with complicated RD and PVR were included in this prospective study. Vitreoretinal surgery with Densiron 68 intraocular tamponade was performed in all patients. Results:The success rate with 1 operation using Densiron 68 was 85.7%, and with further surgery 90.5%. Visual acuity improved from a mean logMAR of 2.25 (SD 0.73) to 1.19 (SD 0.88), p = 0.0001. There was little evidence of dispersion and excessive inflammation. Conclusion:According to the results of this study, vitreoretinal surgery with temporary Densiron 68 intraocular tamponade appears to increase the anatomical success and improve visual acuity, while giving rise to minimal complications, in selected cases of complicated RD and PVR.

To report and discuss the postoperative complications in patients after Densiron 68 intraocular tamponade in the management of complicated retinal detachment with proliferative vitreoretinopathy (PVR).We presented a prospective interventional non-comparative case series of 27 eyes of 27 consecutive patients. Inclusion criteria were PVR, posterior or inferior retinal breaks, and the patient's inability to posture. Vitreoretinal surgery with Densiron 68 intraocular tamponade was performed in all patients. Complications were recorded at 1 week and 1, 2, and 3 months after Densiron 68 intraocular tamponade and after removal of Densiron 68 endotamponade at same periods.The most common complication was posterior capsule opacification and cataract development in seven eyes (25.9%) and in two eyes (25%, 2/8), respectively, the second complication was intraocular inflammation in six eyes (22.2%), the third complication was emulsification and dispersion and raised intraocular pressure in five eyes (18.5%), respectively. The success rate with one operation using Densiron 68 was 85.2% and with further surgery 92.5%. Visual acuity improved from mean logMAR of 2.12 (SD= 0.68) to 1.16 (SD=0.84), P=0.0001.According to the results of this study, postoperative complications did not increase significantly in the vitreoretinal surgery with temporary Densiron 68 intraocular tamponade. Densiron 68 intraocular tamponade is safe and effective in treating complicated retinal detachment.

Rapid thermal annealing (RTA) has been demonstrated as an effective way to improve the crystal quality of GaInNAs(Sb) quantum wells (QWs). However, few investigations have been made into its application in laser growth and fabrication. We have fabricated 1.3 mu m GaInNAs lasers, both as -grown and with post-growth RTA. Enhanced photoluminescence (PL) intensity and decreased threshold current are obtained with RTA, but the characteristic temperature T-o and slope efficiency deteriorate. Furthermore, T-o has an abnormal dependence on the cavity length. We attribute these problems to the deterioration of the wafer's surface. RTA with deposition Of SiO2 was performed to avoid this deterioration, T-o was improved over the samples that underwent RTA without SiO2. Post-growth and in situ annealing were also investigated in a 1.55 mu m GaInNAsSb system. Finally, continuous operation at room temperature of a GaAs-based dilute nitride laser with a wavelength over 1.55 mu m was realized by introducing an in situ annealing process. (c) 2007 Elsevier B.V. All rights reserved.

Sb-assisted GaInNAs/GaAs quantum wells (QWs) with high (42.5%) indium content were investigated systematically. Transmission electron microscopy, reflection high-energy electron diffraction and photoluminescence (PL) measurements reveal that Sb acts as a surfactant to suppress three-dimensional growth. The improvement in the 1.55 mu m range is much more apparent than that in the 1.3 mu m range.. which can be attributed to the difference in N composition. The PL intensity and the full-width at half maximum of the 1.55 mu m single-QW were comparable with that of the 1.3 Am QWs. (c) 2006 Elsevier B.V. All rights reserved.

High structural and optical quality 1.3 mu m GaInNAs/GaAs quantum well (QW) samples with 42.5% indium content were successfully grown by molecular beam epitaxy. The growth of well layers was monitored by reflection high-energy electron diffraction (RHEED). Room temperature photoluminescence (PL) peak intensity of the GaIn0.425NAs/GaAs (6 nm / 20 nm) 3QW is higher than, and the full width at half maximum (FWHM) is comparable to, that of In0.425GaAs/GaAs 3QW, indicating improved optical quality due to strain compensation effects by introducing N to the high indium content InGaAs epilayer. The measured (004) X-ray rocking curve shows clear satellite peaks and Pendellosung fringes, suggesting high film uniformity and smooth interfaces. The cross sectional TEM measurements further reveal that there are no structural defects in such high indium content QWs. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rapid thermal annealing (RTA) has been demonstrated as an important way to improve the crystal quality of GaInNAs(Sb)/GaAs quantum wells. However little investigation has been made into their application in laser growth, especially at a wavelength of 1.55 mu m. When a GaAs-based laser is grown, AlGaAs is usually used for cladding layers. The growth of the p-cladding layer usually takes 30-45 min at a growth temperature higher than that of the GaInNAs(Sb) active region, which affects the material quality. To investigate this effect, various post-growth annealing processes were performed to simulate this process. Great enhancement of the PL intensity was obtained by a two-step process which consisted of annealing first at 700 degrees C for 60 s and then at 600 degrees C for 45 min. We transferred this post-growth annealing to in situ annealing. Finally, a GaInNAsSb laser was grown with a 700 degrees C in situ annealing process. Continuous operation at room temperature of a GaAs-based dilute nitride laser with a wavelength beyond 1.55 mu m was realized for the first time.

Introduction: To report by using topical anesthesia for standing phacoemulsification and intraocular lens implantation for two patients who need cataract extraction but unable to lie flat with marked cervical kyphosis due to long-standing ankylosing spondylitis and chronic uveitis. Methods: Two patients are unable to lie flat respectively during phacoemulsification underwent this technique in Jingdong and Tonghai county Hospital of Yunnan province in China. Each patient was positioned erect or semirecumbent in a standard reclining cataract surgical chair. The ceiling-mounted microscope was rotated 60 degrees from the vertical to point toward the patient. Results: The intraoperative and postoperative periods were uneventful in two patients, with good visual outcomes after surgery. Conclusion: This technique is valuable for situations where the patient requires upright positioning because of the inability to recline flat, and should be considered for cases where standard surgical positioning is not possible.

Photoluminescence (PL) spectra of GaInNAs/GaAs multiple quantum wells and GaInNAs epilayers grown on GaAs substrate show an apparent "S-shape" temperature-dependence of the of dominant luminescence peak. At low temperature and weak excitation conditions, a PL peak related to nitrogen cluster-induced bound states can be well resolved in the PL spectra. It displays a remarkable red shift of up to 60 meV and is thermally quenched below 100 K with increasing temperature, being attributed to N-cluster induced bound states. The indium incorporation exhibits significant effect on the cluster formation. The rapid thermal annealing treatment at 750 C can essentially remove the bound states-induced peak.

We investigated the effects of concomitant In- and N-incorporation on the photoluminescence (PL) of GaInNAs grown by molecular beam epitaxy. In comparison with the N-free GaInAs epilayer, the PL spectra of the GaInNAs epilayer exhibit an anomalous S-shape temperature dependence of dominant luminescence peak. Through further careful inspection, two PL peaks are clearly discerned and are associated with the interband excitonic recombinations and excitons bound to N-induced isoelectronic impurity states, respectively. By comparing the PL spectra of GaInNAs/ GaAs quantum wells (QWs) with those of In-free GaNAs/GaAs QWs grown under similar conditions, it is found that the concomitant In- and N-incorporation reduces the density of impurities and has an effect to improve the intrinsic optical transition of GaInNAs, but also enhance the N-induced clustering effects. At last, we found that rapid thermal annealing can significantly reduce the density of N-induced impurities. (C) 2002 Elsevier Science B.V. All rights reserved.

We have studied the growth of GaInNAs/GaAs quantum well (QW) by molecular beam epitaxy using a DC plasma as the N sourer. The N concentration was independent of the As pressure and the In concentration, but inversely proportional to the growth rate. It was almost independent of T, over the range of 400-500 degreesC, but dropped rapidly when T-g exceeded 500 degreesC. Thermally-activated N surface segregation is considered to account for the strong falloff of the N concentration. As increasing N concentration, the steep absorption edge of the photovoltage spectra of GaInNAs/GaAs QW became gentle, the full-width at half-maximum of the photoluminescence (PL) peal; increased rapidly, and a so-called S-shaped temperature dependence of PL peak energy showed up. All these were attributed to the increasing localized state as N concentration. Ion-induced damage was one of the origins of the localized state. A rapid thermal annealing procedure could effectively remote the localized state. (C) 2001 Elsevier Science D.V. All rights reserved.

An X-ray diffraction method, estimating the strain relaxation in an ultrathin layer, has been discussed by using kinematic and dynamical X-ray diffraction (XRD) theory. The characteristic parameter Delta Omega, used as the criterion of the strain relaxation in ultrathin layers, is deduced theoretically. It reveals that Delta Omega should be independent of the layer thickness in a coherently strained layer. By this method, we characterized our ultrathin GaNxAs1-x samples with N contents up to 5%. XRD measurements show that our GaNxAs1-x layers are coherently strained on GaAs even for such a large amount of N. Furthermore, a series of GaNxAs1-x samples with same N contents but different layer thicknesses were also characterized. It was found that the critical thickness (L-c) of GaNAs in the GaAs/GaNAs/GaAs structures determined by XRD measurement was 10 times smaller than the theoretical predictions based on the Matthews and Blakeslee model. This result was also confirmed by in situ observation of reflection high-energy electron diffraction (RHEED) and photoluminescence (PL) measurements. RHEED observation showed that the growth mode of GaNAs layer changed from 2D- to 3D-mode as the layer thickness exceeded L-c. PL measurements showed that the optical properties of GaNAs layers deteriorated rapidly as the layer thickness exceeded L-c. (C) 2000 Elsevier Science B.V. All rights reserved.

Cubic GaN was grown on GaAs (100) by low pressure metal organic chemical vapor deposition (MOCVD). X-ray diffraction, scanning electron microscope (SEM) and photoluminescence (PL) spectra were performed to characterize the quality of the GaN film. The PL spectra of cubic thin films being thicker than 1.5 μm were reported. Triple-crystal diffraction to analyze orientation distributions and strain of the thin films was also demonstrated.

Cubic GaN films were grown on GaAs(1 0 0) substrates by low-pressure metalorganic vapor-phase epitaxy at high temperature. We have found a nonlinear relation between GaN film thickness and growth timer and this nonlinearity becomes more obvious with increasing growth temperature. We assumed it was because of Ga diffusion through the GaN film, and developed a model which agrees well with the experimental results. These results raise questions concerning the role of Ga diffusion through the GaN film, which may affect the electrical and optical properties of the material. (C) 1998 Published by Elsevier Science B.V. All rights reserved.

To evaluate the visual and anatomical results of surgery for macular hole-related retinal detachment (MHRD) after phacoemulsification cataract extraction.Data for all patients who underwent surgery for MHRD after phacoemulsification cataract extraction from 1 December 1998 to 30 September 2008 in one hospital were evaluated. Patient characteristics, best-corrected visual acuity (VA) preoperatively and at last examination, surgical technique, anatomical success, and follow-up period were extracted and analysed statistically.A total of 13 625 eyes of 10 076 patients who had phacoemulsification cataract surgery were included. In the follow-up period, 10 cases of MHRD in nine patients were observed, of which seven eyes had high myopia. The mean axial length was 30.97 ± 1.36 mm (29.19, 32.97) and mean myopia was-19.35 ± 1.93 (-7.5,-3.5) dioptres. Overall anatomical success was achieved in 90% (9 out of 10 eyes). There was no statistically significant difference (P=0.240) between the logarithm of the MAR VA before the phacoemulsification cataract extraction and after MHRD surgical repair. VA increased in three eyes but decreased in the other seven after MHRD surgery.As a primary procedure, vitreous surgery combined with other necessary adjunct procedures such as membrane peeling and retinal tamponade seems to be successful in achieving anatomical success. However, VA improvement is dependent on the type of macular lesion and not the surgical procedure.

Purpose: To evaluate the outcome, intraoperative and postoperative complications of refractive lens exchange (RLE) by phacoemulsification with posterior chamber intraocular lens (IOL) implantation combined with simultaneous pars plana vitrectomy (PPV) in the management of high myopia. Methods: This prospective study consisted of 45 eyes of 26 patients with preoperative myopia greater than –12.5 dpt. Clear lens phacoemulsification with IOL implantation surgery was combined with PPV. Main outcome measures were best-corrected visual acuity (BCVA), stability of the spherical equivalent (SE) and complications at follow-up. Results: The combined procedure of clear lens phacoemulsification combined with PPV has a favorable outcome with acceptable SE predictability and improvement in BCVA. The postoperative BCVA was 0.67 ± 0.21 compared to 0.15 ± 0.10 preoperatively (p < 0.001). The mean postoperative SE was –1.6 ± 0.9 dpt, showing a significant difference when compared with a mean value of –20.0 ± 5.2 dpt before the operation (p < 0.001). During the follow-up, all IOLs were placed stably in the bag with no capsular tear occurring and only 1 case (2.2%) developed retinal detachment. Conclusion: RLE and implantation of an IOL combined with simultaneous PPV is a reasonable refractive surgery option for middle-aged patients with high myopia.

Introduction. To report a case of anterior sclera staphyloma and vitreous hemorrhage occurring over 38 years after bilateral cataract surgery.Methods. A 58-year-old man presented with anterior sclera staphyloma and vitreous hemorrhage in the right eye, after bilateral cataract surgery, over 38 years ago. We performed combined anterior sclera staphylectomy and vitrectomy of right eye for anterior sclera staphyloma and vitreous hemorrhage.Results. Forty-eight months after the combined surgery, best-corrected visual acuity was 0.3 (+10.00/−4.50 × 60) with eutopic stitches of the corneoscleral junction on the superior nasal quadrant and a stable ocular surface.Conclusions. This is the first reported case of anterior sclera staphyloma with vitreous hemorrhage successfully managed by combined surgery.

We have investigated the Wannier-Stark effect in GaAs/${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{Al}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$As superlattices under electric fields by photocurrent spectroscopy measurements in the range of temperatures 10\char21{}300 K. The linewidth of the 0h Stark-ladder exciton was found to increase significantly along with an increase in peak intensity when the electric field increases. We present a mechanism based on an enhanced interface roughness scattering of electronic states due to Wannier-Stark localization in order to explain this increased broadening with electric field. This electric-field-related scattering mechanism will weaken the negative differential conductance effects in superlattices predicted by Esaki and Tsu.

The optical properties of cubic GaN films have been investigated in the temperature range of 10–300 K. Five peaks were observed at 10 K. From the dependence of photoluminescence emissions on the temperature and excitation intensity, we have assigned two of the five peaks (2.926 and 2.821 eV) to donor–acceptor pair (DAP) transitions. Furthermore, these two peaks were found to be related to a common shallow donor involved in the peak position previously reported at 3.150 eV. The intensities of DAP transitions were much weaker than that of excitonic emission even at low temperature, indicating a relatively high purity of our samples.

We have investigated the interband electron transitions in a GaNAs/GaAs single quantum well (QW) by photoluminescence and absorption spectra. The experimental results show that the dominant photoluminescence at low temperature and high excitation intensity originates from transitions within the GaNAs layer. The interband transition energy for QWs with different well widths can be well fitted if a type-II band line up of GaNAs/GaAs QWs is assumed. (C) 2000 American Institute of Physics. [S0003-6951(00)03220-4].

The mechanism of room-temperature optical transitions in a Mg-doped cubic GaN epilayer grown on GaAs(100) by metalorganic chemical vapor deposition has been investigated. By examining the dependence of photoluminescence on the excitation intensity (which varied over four orders) at room temperature, four different emissions with different origins were identified. A blue emission at similar to 3.037 eV was associated with a shallow Mg acceptor, while three different lower-energy emissions at similar to 2.895, similar to 2.716, and similar to 2.639 eV were associated with a deep Mg complex. In addition to a shallow acceptor at E congruent to 0.213 eV, three Mg-related deep defect levels were also found at around 215, 374, and 570 meV (from the conduction band). (C) 2000 American Institute of Physics. [S0021-8979(00)01904-6].

Purpose: This study aimed to evaluate the longterm results of phacovitrectomy and foldable intraocular lens (IOL) implantation in eyes with significant cataract and co-existing vitreoretinal diseases. Methods: We carried out a retrospective study of 186 eyes of 149 patients with various vitreoretinal abnormalities and visually significant cataracts. Vitreoretinal surgery was combined with phacoemulsification and foldable IOL implantation. Main outcome measures were visual acuity (VA), preoperative data, and intraoperative and postoperative complications. Results: The most common indications for surgery were non-diabetic vitreous haemorrhage and proliferative diabetic retinopathy. Preoperative vision ranged from 0.6 to light perception; postoperative vision ranged from 1.2 to no light perception. Postoperatively, in 162 eyes (87.1%) VA improved by ≥ 3 lines on the decimal chart. In 14 eyes (7.5%), vision remained within 3 lines of preoperative levels and in 10 eyes (5.3%), vision had decreased by the last follow-up. Postoperative complications included elevated intraocular pressure and posterior capsule opacification, corneal edema, macular edema, fibrinous reaction, vitreous hemorrhage, corneal epithelial defects, anterior chamber hyphema, choroidal detachment, persistent macular hole, posterior synechiae, recurrent retinal detachment, rubeosis iridis, neovascular glaucoma. Conclusions: Combined vitreoretinal surgery and phacoemulsification with foldable IOL implantation is safe and effective in treating vitreoretinal abnormalities co-existing with cataract. Based on extensive experience with the combined procedure, we suggest that combined surgery is recommended in selected patients with simultaneous vitreoretinal pathological changes and cataract.

Purpose In an earlier study we found normal adeno-associated viral vector type 2 (AAV2)-mediated GFP expression after intravitreal injection to one eye of normal C57BL/6J mice. However, GFP expression was very poor in the partner eye of the same mouse if this eye received an intravitreal injection of the same vector one month after the initial intravitreal injection. We also found both injections worked well if they were subretinal. In this study, we tested whether the efficiency of subretinal AAV vector transduction is altered by a previous intravitreal injection in the partner eye and more importantly whether therapeutic efficiency is altered in the rd12 mouse (with a recessive RPE65 mutation) after the same injection series. Methods One μl of scAAV5-smCBA-GFP (1x1013 genome containing viral particles per ml) was intravitreally injected into the right eyes of four-week-old C57BL/6J mice and 1 μl of scAAV5-smCBA-hRPE65 (1x1013 genome containing viral particles per ml) was intravitreally injected into the right eyes of four-week-old rd12 mice Four weeks later, the same vectors were subretinally injected into the left eyes of the same C57BL/6J and rd12 mice. Left eyes of another cohort of eight-week-old rd12 mice received a single subretinal injection of the same scAAV5-smCBA-hRPE65 vector as the positive control. Dark-adapted electroretinograms (ERGs) were recorded five months after the subretinal injections. AAV-mediated GFP expression in C57BL/6J mice and RPE65 expression and ERG restoration in rd12 mice were evaluated five months after the second subretinal injection. Frozen section analysis was performed for GFP fluorescence in C57BL/6J mice and immunostaining for RPE65 in rd12 eyes. Results In rd12 mice, dark-adapted ERGs were minimal following the first intravitreal injection of scAAV5-smCBA-RPE65. Following subsequent subretinal injection in the partner eye, dramatic ERG restoration was recorded in that eye. In fact, ERG b-wave amplitudes were statistically similar to those from the eyes that received the initial subretinal injection at a similar age. In C57BL/6J mice, GFP positive cells were detected in eyes following the first intravitreal injection around the injection site. Strong GFP expression in both the retinal pigment epithelium (RPE) and photoreceptor (PR) cells was detected in the partner eyes following the subsequent subretinal injection. Immunostaining of retinal sections with anti-RPE65 antibody showed strong RPE65 expression mainly in the RPE cells of subretinally injected eyes but not in the intravitreally injected eyes except minimally around the injection site. Conclusions These results show that an initial intravitreal injection of AAV vectors to one eye of a mouse does not influence AAV-mediated gene expression or related therapeutic effects in the other eye when vectors are administered to the subretinal space. This suggests that the subretinal space possesses a unique immune privilege relative to the vitreous cavity.

We report some investigations on vertical cavity surface emitting laser (VCSEL) arrays and VCSEL based optoelectronic smart photonic multiple chip modules (MCM), consisting of 1/spl times/16 vertical cavity surface emitting laser array and 16-channel lasers driver 0.35 /spl mu/m CMOS circuit. The hybrid integrated multiple chip modules based on VCSEL operate at more than 2 GHz in -3 dB frequency bandwidth.