Effectiveness and safety of early lens extraction during par plana vitrectomy for proliferative diabetes retinopathy with mild cataract: a randomized clinical trial.

AIM: To evaluate the effectiveness and safety of early lens extraction during pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR) compared to those of PPV with subsequent cataract surgery. METHODS: This multicenter randomized controlled trial was conducted in three Chinese hospitals on patients with PDR, aged >45y, with mild cataracts. The participants were randomly assigned to the combined (PPV combined with simultaneously cataract surgery, i.e., phacovitrectomy) or subsequent (PPV with subsequent cataract surgery 6mo later) group and followed up for 12mo. The primary outcome was the change in best-corrected visual acuity (BCVA) from baseline to 6mo, and the secondary outcomes included complication rates and medical expenses. RESULTS: In total, 129 patients with PDR were recruited and equally randomized (66 and 63 in the combined and subsequent groups respectively). The change in BCVA in the combined group [mean, 36.90 letters; 95% confidence interval (CI), 30.35-43.45] was significantly better (adjusted difference, 16.43; 95%CI, 8.77-24.08; P<0.001) than in the subsequent group (mean, 22.40 letters; 95%CI, 15.55-29.24) 6mo after the PPV, with no significant difference between the two groups at 12mo. The overall surgical risk of two sequential surgeries was significantly higher than that of the combined surgery for neovascular glaucoma (17.65% vs 3.77%, P=0.005). No significant differences were found in the photocoagulation spots, surgical time, and economic expenses between two groups. In the subsequent group, the duration of work incapacity (22.54±9.11d) was significantly longer (P<0.001) than that of the combined group (12.44±6.48d). CONCLUSION: PDR patients aged over 45y with mild cataract can also benefit from early lens extraction during PPV with gratifying effectiveness, safety and convenience, compared to sequential surgeries.

Celastrol inhibits laser-induced choroidal neovascularization by decreasing VEGF induced proliferation and migration.

AIM: To evaluate celastrol's effect on choroidal neovascularization (CNV). METHODS: In this study, neovascular formation in vitro (tube formation and aortic ring culture) and in vivo (laser induced neovascular in mice) was treated with celastrol to evaluate this natural compound's impact on CNV. Western blot was applied to explore the possible mechanism for it. For in vitro assay, triplicate for each group was repeated at least three times. For in vivo assay, each group contains 5 mice. RESULTS: Celastrol supressed tube formation and aortic ring sprout neovascularization. In vitro assay exhibited that celastrol inhibiting vascular endothelial growth factor (VEGF)-induced proliferation and migration of human umbilical vein endothelial cells and human choroidal endothelial cells, and by blocking VEGF signaling. Furthermore, intraperitoneal administration of celastrol significantly reduced the area of laser-induced CNV in an in vivo mouse model. By day 14, the area of CNV had decreased by 49.15% and 80.26% in the 0.1 mg/kg celastrol-treated group (n=5) and in the 0.5 mg/kg celastrol treated group (n=5), respectively, compared to the vehicle-treated group (n=5). CONCLUSION: Celastrol inhibits CNV by inhibiting VEGF-induced proliferation and migration of vascular endothelial cells, indicating that celastrol is a potent, natural therapeutic compound for the prevention of CNV.

Ultrasound-targeted cationic microbubble-mediated gene transfection and inhibition of retinal neovascularization.

AIM: To investigate whether ultrasound-targeted cationic microbubbles (CMBs) destruction could deliver endostatin-green fluorescent protein (GFP) plasmids efficiently to the human retinal endothelial cells (HRECs) and inhibit retinal neovascularization in mice. METHODS: CMBs were prepared and the presentation of GFP reporter was confirmed by flow cytometry and laser confocal microscopy. Experiments assessing HRECs migration and vascular formation were performed to evaluate gene therapy's efficiency in vitro. A mouse model of oxygen-induced retinopathy was employed and the expression of Bcl-xl, Bcl-2, vascular endothelial growth factor (VEGF) and endostatin in the retina of mice were determined by Western blotting and quantitative polymerase chain reaction (qPCR). The expression of endostatin-GFP in the retina was examined by laser confocal microscopy at 5, 14, and 28d after treatment. RESULTS: The gene expression of endostatin was the highest in the group of the CMBs. Besides, the inhibition and antiangiogenesis effect of the migration and development of HRECs were improved following treatment with CMBs compared with the other groups in vitro. In vivo, retinal neovascularization was significantly inhibited and the fluorescence intensity of endostatin-GFP in the mouse retina was importantly higher in the group of CMBs than that in other groups. CONCLUSION: The research illustrates ultrasound-targeted CMBs destruction possessed distinct effect on the inhibition of the vascular formation and the development of retinal neovascularization both in vitro and in vivo.

The molecular design of performance-enhanced intraocular lens composites.

Intraocular lens (IOL) implantation surgery is quite effective in the treatment of blindness caused by cataracts. However, in clinical applications, IOLs readily form glistening. This phenomenon usually occurs for a period after IOL implantation ranging from a few months to several years. The molecular mechanism of the formation of glistening in IOLs is still inconclusive. Failure to understand and explain the molecular mechanism of glistening formation greatly hinders the design and application of new glistening-free IOL materials. Here, in this study, we use molecular dynamics simulation methods to conduct in-depth research on the molecular mechanism of the glistening formation of IOLs, aiming to provide a possible molecular mechanism of glistening. Furthermore, based on this molecular mechanism, we propose a novel strategy of a glistening-free material based on a composite design method to reasonably copolymerize several types of molecules or functional groups, so that the glistening phenomenon can be effectively eliminated. The possible molecular mechanism of glistening formation proposed in this research can offer a solid theoretical basis and guidance for the subsequent construction of glistening-free IOL materials.

Vitreoretinal surgeons' experience and time interval from pars-plana vitrectomy to cataract extraction.

AIM: To identify the association of the vitreoretinal surgeons' experience with the time interval between pars-plana vitrectomy (PPV) and cataract extraction (CE). METHODS: Eyes with prior PPV and following CE were included in this retrospective cohort study. The years of practice and the annual case volume were used to describe the surgeons' experience. Multivariable linear regression analysis was used to investigate the relationship between surgeons' experience and the time interval adjusted for the patients age, gender, intraocular tamponade, and case complexity. RESULTS: Of 132 430 eyes, 1445 eyes were included in this study. In multivariable linear regression analysis, cases performed by surgeons with >20 practice years had longer time intervals compared with surgeons with <10 practice years after adjusted for other variables (ß=0.329, 95%CI: 0.113 to 0.549, P=0.003). No difference in time interval was detected for comparing the lowest with the highest volume groups (ß=0.089, 95%CI: -0.164 to 0.343, P=0.343). The surgeons' practice years were not directly with the volume. For complicated surgery, the higher-practice-year surgeons had longer time interval than lower-practice-year surgeons. CONCLUSION: The time intervals from PPV to CE is longer in higher-practice-year surgeons. The surgeons' practice years may have a greater effect on the time interval than annual case volume in high-complexity cases. Matching the complexity of vitreoretinal diseases with the surgeons' practice year should be considered.

Accuracy of eight intraocular lens power calculation formulas for segmented multifocal intraocular lens.

AIM: To evaluate the accuracy of eight different intraocular lens (IOL) power calculation formulas for a segmented multifocal IOL. METHODS: A total of 53 eyes of 41 adult cataract patients who underwent phacoemulsification and implantation with the SBL-3 segmented multifocal IOL between January 1, 2017 and January 31, 2019 were included in this retrospective study. Preoperative biometry measurements were obtained using an IOL Master. Manifest refraction was performed at least 4wk postoperatively. Accuracy of the eight formulas [Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Hill-RBF 2.0, Hoffer Q, Holladay 1, Kane, and SRK/T] was analyzed. RESULTS: Using current lens constants, all formulas exhibited errors of slight myopic shift in refractive prediction. The Barrett Universal II formula had a significantly lower median absolute error (MedAE) than did Holladay 1 (P=0.02), Kane (P=0.001) and Hill-RBF 2.0 (P<0.001) formulas. The Haigis formula had a lower MedAE value than did the Hill-RBF 2.0 formula (P=0.005). Differences in MedAE values among SRK/T, EVO and Hoffer Q formulas were not significant. After optimizing lens constants, the MedAE values of all formulas were reduced; significant changes were noted for EVO (P=0.022), Haigis (P=0.048), Hill-RBF 2.0 (P=0.014), Holladay 1 (P=0.045) and Kane (P=0.022) formulas. All formulas performed equally well after optimization of lens constants (P=0.203). CONCLUSION: All eight formulas tend to result in a myopic shift when using current lens constants. Optimized lens constants improve the accuracy of these formulas among adult Chinese patients.

A computerized resolution visual acuity test in preschool and school age children.

AIM: To develop a novel approach called the Autoacuity Tester, and to evaluate its validity, especially the sensitivity and specificity for detecting amblyopia. METHODS: Children aged from 3 to 12y (n=552) were enrolled in the study. The validity of the Autoacuity Tester was evaluated by comparing it to the Tumbling E Early Treatment Diabetic Retinopathy Study (ETDRS) acuity chart for school age children, and Lea Symbols and Teller acuity card (TAC) for preschool children. The repeatability was assessed by coefficient of repeatability (COR). The sensitivity and specificity for detecting amblyopia were calculated. RESULTS: The mean difference (95% limits of agreement) between the Autoacuity Tester and the ETDRS tests were -0.03 (-0.24, 0.19) logMAR for the school age group. In preschool children, the mean difference was 0.04 (-0.14, 0.21) logMAR between the Autoacuity Tester and the TAC and 0.00 (-0.17, 0.18) logMAR between the Autoacuity Tester and the Lea Symbols. For the school age group, the COR was 0.20 logMAR for the Autoacuity Tester and 0.18 logMAR for the ETDRS. For the preschool group, the COR was 0.13 logMAR for the Autoacuity Tester and 0.21 logMAR for TAC. The Autoacuity Tester (88%) is more sensitive than TAC (72%) in detecting amblyopia (P=0.04), while had similar specificity (92% vs 90%, P=0.20). CONCLUSION: The Autoacuity Tester provides a reliable alternative for assessing visual acuity, and offers advantage of higher testability and repeatability for preschool children.

Dynamic profile of ocular refraction in pediatric cataract patients after lens surgeries.

AIM: To study the change in ocular refraction in patients with pediatric cataracts (PCs) after lens extraction. METHODS: A total of 1258 patients who were undergoing cataract extraction with/without intraocular lens (IOL) implantation were recruited during preoperative examinations between Jan 2010 and Oct 2013. Patient ages ranged from 1.5mo to 14y. Follow-ups were conducted at 1wk, 1, and 3mo postoperatively and every 3mo in the first year, then 6mo thereafter. Ocular refraction [evaluated as spherical equivalent (SE)] and yearly myopic shift (YMS) were recorded and statistically analyzed among patients with age at surgery, baseline ocular refraction, gender, postoperative time and laterality (bilateral vs unilateral). RESULTS: By Dec 31st 2015, 1172 participants had been followed for more than 2y. The median follow-up period was 3y. The critical factors affecting the ocular refraction of PC patients were baseline ocular refraction, postoperative time for both aphakic and pseudophakic eyes. YMS grew most rapidly in young childhood and early adolescence. CONCLUSION: After lens surgeries, ocular refraction in PC patients shows an individual difference of change. Further concerns should be raising to monitor the rapid myopic shift at early adolescence of these patients.

Effect of Adventitial Dissection of Superficial Temporal Artery on the Outcome of Superficial Temporal Artery-Middle Cerebral Artery Bypass in Moyamoya Disease.

Superficial temporal artery-middle cerebral artery (STA-MCA) has been used for the treatment of occlusive cerebrovascular disease including moyamoya disease. The effect of STA-MCA bypass depends not only on the patency of anastomosis, but also on integrity and functional capacity of the donor artery. In the present prospective study, we investigated the effect of extensive stripping STA adventitia and fasciae on hemodynamic function in STA-MCA bypass of moyamoya disease patients. Twenty patients (n=8 in control group, n=12 in stripping group) of moyamoya disease were subjected to STA-MCA end-to-side direct anastomosis. Perfusion unit (PU) values of the cortex were measured and recorded using a Laser Doppler flowmetry (LDF) for 5 days. Computed tomography perfusion was performed to determine blood flow before and after bypass. No patient experienced significant neurologic deficits associated with neurosurgical complications. LDF demonstrated that adventitial stripping group had higher cerebral blood flow increase than control group. The adventitia stripping group tends to have higher rate of increased cerebral perfusion after bypass than non-stripping group. Furthermore, the ultrasound examination at 3 days after bypass demonstrated that the adventitial stripping group has a tendency of bigger STA and higher peak systolic velocity than control group. Our result suggests that stripping adventitia of STA improves hemodynamics of STA-MCA bypass in moyamoya disease.

Objective evaluation of the changes in the crystalline lens during accommodation in young and presbyopic populations using Pentacam HR system.

AIM: To quantify the changes in the lens profile with accommodation in different age groups. METHODS: The Pentacam HR system was used to obtain the images of the anterior eye segment from 23 young and 15 presbyopic emmetropic subjects in unaccommodated (with an accommodation stimulus of 0.0D) and accommodated (with an accommodation stimulus of 5.0D for the young group and 1.0D for the presbyopic group) states. The phakic crystalline lens shape, including curvature of crystalline lens and central lens thickness (CLT), and the measurements of anterior segment length (ASL), central anterior chamber depth (CACD) were investigated. The anterior chamber volume (ACV) was also measured. RESULTS: The reduction of CACD and ACV were significant in both groups after accommodation stimulus. From the profile of anterior eye segment, a significant decrease in anterior crystalline lens radii of curvature (-2.52mm) and a mean increase in CLT (0.222mm) and ASL (0.108mm) were found in the young group with an accommodation stimulus of 5.0D. However, no statistically significant changes of CLT, ASL, or crystalline lens radii of curvature were found in the presbyopic group. CONCLUSION: Our data showed that the shallowing of anterior chamber during accommodation was caused by the forward bulging of the anterior lens surface, rather than by anterior shifting of lens position in either young or presbyopic subjects.

Difference of gene expression between the central and the peripheral epithelia of the bovine lens.

BACKGROUND: Equatorial lens epithelial cells proliferate and differentiate into fiber cells throughout life, while central lens epithelial cells proliferate little and do not form fiber cells. This study aimed to investigate the differences in gene expression between the central and the peripheral epithelial cells of the bovine lens. METHODS: Lens epithelia were dissected into central (

Biological characters of [18F]O-FEt-PIB in a rat model of Alzheimer's disease using micro-PET imaging.

AIM: To evaluate whether the newly-synthesized positron emission tomography (PET) tracer, [18F]2-(4'-(methylamino)phenyl)-6-fluoroethoxy- benzothiazole ([18F] O-FEt-PIB), could bind to beta-amyloid aggregates in a rat model of Alzheimer's disease (AD) using micro-PET. METHOD: [18F]O-FEt-PIB was synthesized and purified by radio HPLC. PET imaging was performed with a R4 rodent model scanner in 3 model and 3 control rats. Dynamic PET scans were performed for 40 min in each rat following an injection of approximately 37 MBq of [18F]O-FEt-PIB. Static scans were also performed for 15 min in each rat. PET data were reconstructed by a maximum posteriori probability algorithm. On the coronal PET images, regions of interest were respectively placed on the cortex, hemicerebrum [including the hippocampus and thalamus (HT)], and were guided by a 3-D digital map of the rat brain or the brain images of [18F]2-Deoxy-2-fluoro-D-glucose ([18F]FDG) in normal rats. Time-activity curves (TAC) were obtained for the cerebrum and cerebellum. The activity difference value (ADV) between 2 hemicerebrums was also calculated. RESULTS: The TAC for [18F]O-FEt-PIB in the cerebrum or cerebellum peaked early (at approximately 2 min), but washed out a little slowly. In the dynamic and static micro-PET images, increased radioactivity was found in the area of the right HT in the model rats where infused with beta-amyloid (1-40). No distinct difference of radioactivity was found between the right and left HT areas in the control rats. The ADV(HT) was approximately 14.6% in the AD model rats and approximately 4 times greater than that of the control rats (3.9%). CONCLUSION: To our knowledge, this study is the first to evaluate a small molecular PET probe for the beta-amyloid deposits in vivo using micro-PET imaging in an AD-injected rat model. The suitable biological characters showed that the tracer had potential to be developed as a probe for detecting beta-amyloid plaques in AD.

[Changes of blood-aqueous barrier after phacoemulsification in patients with previous glaucoma filtering surgery].

OBJECTIVE: To evaluate the effect of trabeculectomy and/or phacoemulsification surgery on blood-aqueous barrier function. METHODS: Phacoemulsification with implantation of intraocular lens was performed on 46 cataract eyes of 40 glaucoma patients following previous trabeculectomy (group 1), and 64 cataract eyes of 60 patients (group 2). The aqueous flare and cells were examined preoperatively and on days 1, 7, 30, 90 postoperatively using a laser flare-cell meter (LFCM). RESULTS: The mean aqueous flare values were (15.12 +/- 2.87), (40.24 +/- 3.75), (24.33 +/- 3.38), (21.18 +/- 1.77), (16.51 +/- 1.70) photon counts/ms in group 1 preoperatively and on days 1, 7, 30, 90 after surgery (P < 0.05) respectively; and were (6.94 +/- 2.34), (26.27 +/- 10.21), (13.96 +/- 6.44), (9.07 +/- 2.67), (7.16 +/- 1.89) photon counts/ms in group 2 (P < 0.05) respectively. CONCLUSIONS: Trabeculectomy can breakdown blood-aqueous barrier permanently while phacoemulsification damage the blood-aqueous barrier transiently. Phacoemulsification combined with a previous trabeculectomy can enhance this damage.

[A preliminary report on bimanual microphacoemulsification].

OBJECTIVE: To evaluate the surgical technique, feasibility, and outcome of bimanual microphacoemulsification. METHODS: The preliminary clinical study included 132 senile cataract eyes. A temporal clear cornea incision was made using 19G microvitreoretinal blade with the exterior incision length of 1.4 mm, the interior incision length of 1.2 mm, and the tunnel length of 1.0 mm. A 1.2 mm x 1.0 mm clear cornea side port was created with 19G microvitreoretinal blade at 12 o'clock in the right eye or 6 o'clock in the left eye. A sleeveless titanium phaco needle with an outer diameter of 0.9 mm was inserted through the temporal clear cornea incision. An irrigating chopper was inserted through the side port as the left-hand instrument, bimanual nucleofractis and nuclear emulsification were performed using quick chop technique. The lens cortical removal was performed bimanually with the Duet Bimanual I/A System. The study parameters included phacoemulsification time, intraoperative complications and early postoperative outcome. RESULTS: The mean Phacoemulsification time was 0.75 +/- 0.64 min. vision acuity equal or better than 0.5 were 55.30%, 87.12% and 90.15% after surgery one day, one week and one mother respectively. Eyes with 0.5 best corrected visual acuity amounted to 90.91%, while with 0.8, amounted to 77.27% all the treated eyes 1 month postoperation. The formation of anterior chamber was successfully maintained in every case. There was various degree of nuclear hardness in all of case studied. CONCLUSION: Bimanual microphacoemulsification is a feasible, secure, and effective surgery for cataract extraction through a sub-1.5 mm clear cornea incision.

[Clinical applications of ultrasound biomicroscopy in diagnosis and treatment of lens subluxation].

OBJECTIVE: To evaluate the clinical value in diagnosis and treatment of lens subluxation using ultrasound biomicroscopy (UBM). METHOD: This study comprised 29 patients (32 eyes) that had cataract with subluxated lenses due to different causes admitted into our hospital between November 2000 and January 2002. All eyes received UBM examination preoperatively and postoperatively. Capsular tension ring (CTR) implantations were performed using different technique according to UBM examination. Then all patients received phacoemulsification and intraocular lens (IOL) implantation. The location of IOL and CTR and complications were evaluated postoperatively. RESULTS: Different kinds of subluxated lens shown different manifestations in UBM. The degree of zonular defect can be evaluated with UBM preoperatively. With UBM examination preoperatively, extent of lens subluxation less than 1/2 quadrant in 19 eyes while more than 1/2 quadrant in other 13 eyes were observed. Postoperative UBM examination in this series shown that CTRs were holding in place except one attached to the iris root. IOLs in 29 eyes were in proper position while IOLs in 3 patients were slightly tilted. CONCLUSIONS: The degree and extent of lens subluxation can be evaluated using UBM examinations preoperatively, which is necessary in the selection of surgical protocol. With postoperative UBM examinations, a precise observation on the actual location of CTR and IOL can be achieved to produce an objective evaluation of the surgical outcomes.

[The causes and reposition of fixed intraocular lens pupillary capture in children].

OBJECTIVE: To analyze the cause of fixed intraocular lens (IOLs) pupillary capture in children and investigate the rational methods to reposit intraocular lens. METHODS: Thirty-one eyes (30 cases) with fixed intraocular lens pupillary capture under 14 years old were analyzed based on clinical data; the causes and the complications were also evaluated. The IOL reposition procedure was performed in 8 cases (8 eyes) with severe complications. RESULTS: Different extent of secondary cataract, posterior iris synechia caused by severe postoperative uveal tract reaction were existed in all 30 cases, corecleisis was occurred in some severe cases. During reposition operation, different extent of lens cortex regeneration in the equator portion of capsule bag was found in all eight cases. CONCLUSION: Fixed pupillary capture of IOL is the common complication in children after cataract surgery. Severe postoperative uveal tract reaction and secondary cataract and lens cortex regeneration are the major causes of intraocular lens pupillary capture. The intraocular lens could be reposited through iris synechia separation, regenerated lens cortex cleaning and secondary cataract extraction.

[Identification of rabbit lens proteins by two-dimensional gel electrophoreses and mass spectrometry].

OBJECTIVE: To study the role of lens proteomics using two-dimensional electrophoresis (2-DE) and mass spectrometry in order to exploring novel effective ways for cataract prevention and therapy. METHODS: The proteins of the three-month-year old rabbit lens were separated using immobilized pH gradients 2-DE. Image analysis was carried out using Image Master 2D Elite 3.01 software package. Most of the crystallines was identified by matrix assisted laser adsorption/ionization-time of-flight-mass spectrometry (MALDI-TOF-MS). RESULTS: The maps of 2-DE showed that lens proteins were in the section of pH 5 - 9 and the relative molecular weight was 14,000 - 94,000, while relative molecular weight of more abundant crystalline was localized at 14,000 - 40,000. About 180 protein spots were detected with the similar PI, molecular weight and quantity of each spot could be acquired by image analysis software. Sixteen crystallines were identified using MALDI-TOF-MS. CONCLUSION: Proteomic analysis of lens can be accomplished and the proteins can be well separated and analyzed using 2-DE and mass spectrometry. This technique offers a new avenue for analyses of lens proteins and to assess their differential expression in cataract, and may thus provide a novel approach to cataract prevention and therapy.

[Effects of exogenous p21 gene on cells cycle of human lens epithelial cells].

OBJECTIVE: To investigate the effects of transfected exogenous p21 gene on the cells cycle of HLE-B3 cells line. The feasibility of prevention of secondary cataract by gene therapy was evaluated. METHODS: Total length of human p21 gene cDNA was cloned on the parent's plasmid pcDNA3 to construct the recombinant plasmids of pcDNA3/p21, a large amount of pcDNA3/p21 plasmid DNA was prepared by QIAGEN endofree maxi kit. After harvest of the plasmid DNA, the HLE-B3 cells line was transfected. The cell growth was observed and the cells cycle was analyzed by flow cytometry. The expression of p21 mRNA was detected by RT-PCR and the expression of p21 protein was detected by immunohistochemistry and western blot analysis. RESULTS: Forty eight hours after transfection, the growth of transfected cells became slower, some cells floated and died; the control cells and blank plasmid (blank pcDNA3) transfected cells grew normally. Flow cytometry analysis revealed that the number of cells in G(1) phase increased markedly in transfected cells. The RT-PCR showed that the product of p21 in the transfected cells (dead or alive cells) was obviously higher than that of the controls. Immunohistochemical studies showed few positive cells in the controls, and very high positive signal was detected after transfection. Western blot showed a positive band at the level of 21 000 in transfected cells, no positive band could be found in the controls. CONCLUSION: Exogenous p21 gene can transfect the HLE-B3 cells and can be expressed. The transfection can affect the cells cycle by G(1) arrest and induces cells death through the apoptosis process. This result suggests that it is possible to prevent the occurrence of secondary cataract by gene therapy.