Ex-PRESS Glaucoma Shunt Treating Coexisting Cataract And Primary Open Angle Glaucoma

Part Ⅰ Purposes: To investigate the clinical efficacy of Ex-PRESS glaucoma mini-shunt implantation combined phacoemulsification in coexisting cataract and primary open angle glaucoma.Methods: This study is a randomized,prospective,12 months clinical trial which started from September 2018 to September 2020.Patients with coexisting cataract and primary open angle glaucoma are collected from ophthalmology department of Guangdong people hospital with 70 patients(70 eyes)in total.For Phaco-Ex PRESS group,35 eyes underwent Ex-PRESS glaucoma mini-shunt implantation combined phacoemulsification,and 35 eyes underwent trabeculectomy combined with phacoemulsification in Phaco-Trab group.Best corrected visual acuity(BCVA),intraocular pressure(IOP),visual field test,average peripapillary retinal nerve fiber layer(Average p RNFL),Indian bleb appearance grading scale(IBAGS),and postoperative complications were collected in both groups.The follow-up timepoint were postoperative 2 weeks,1 month,3 months,6 months and 12 months.Target pressure was defined as: 1)for mild visual field defect,IOP reduction≥20% and IOP≤21mm Hg,2)for moderate visual field defect,IOP reduction≥30% and IOP≤18mm Hg,3)for severe visual field defect,IOP reduction≥40% and IOP≤15mm Hg.Complete successful bleb was defined as the target IOP can be reached without antiglaucoma medication and visual acuity decrease no more than 2 lines(Snellen chart),while partial successful bleb was defined as the target IOP can be reached with antiglaucoma medication usage and visual acuity decrease no more than 2 lines(Snellen chart).Results: During 12 months-follow up,two patients(5.71%)in Phaco-Ex PRESS group and one patient(2.86%)in Phaco-Trab group are lost.The BCVA of both groups were improved no less than 2 lines.In Phaco-Ex PRESS group and Phaco-Trab group,IOP is change from 21.61±5.72 mm Hg and 21.60±3.49 mm Hg preoperatively to 12.57±2.81 mm Hg and 13.29±3.67 mm Hg postoperatively,respectively,resulting in IOP reduction of 8.70±5.42 mm Hg and 8.41±4.53 mm Hg(P=0.82).Postoperative IOP in each timpoint is lower than the baseline in both groups(P<0.01).Except postoperative 2 weeks and 1 month,the IOP of two groups had no statistical differences.At postoperative 12 months,Phaco-Ex PRESS group showed decrease in number of antiglaucoma medications when compare with preoperative medications usage(2.42±1.20 VS 0.24±0.56,P<0.01),while in Phaco-Trab group,no statistical difference was detected in preoperative and postoperative 12 months medications usage.When compare the number of antiglaucoma medication usage in two groups,Phaco-Ex PRESS group is significantly lower than Phaco-Trab group at 12 months postoperatively.At postoperative 12 months,the complete successful rate is 69.70%(23 eyes)in PhacoEx PRESS group and 35.29%(12 eyes)in Phaco-Trab group(P<0.01).The qualified successful rate is 75.76%(25 eyes)in Phaco-Ex PRESS group and 64.70%(22 eyes)in Phaco-Trab group(P=0.43).The main early postoperative complications were bleb leakage,shallow anterior angle and early bleb encapsulation,while no statistical difference was found between two groups(P>0.05).No severe complications,for example,choriodal detection,choriodal hemorrhage,continuous low IOP,or corneal endothelial decompensation etc.were found.Conclusions: Phacoemulsification combined with Ex-PRESS glaucoma mini-shunt implantation and phacotrabeculectomy both are clinical effecitve and save in lowering IOP and improve visual acuity of patients with coexisting cataract and primary open angle glaucoma.However,the former can decrease the postoperative antiglaucoma medication number and has better control in IOP.Part Ⅱ Purposes: Using in vivo confocal microscopy(IVCM),the second part of the research is to analyze the filtering bleb morphology and function after phacoemulsification combined with Ex-PRESS glaucoma mini-shunt implantation.Methods: The same as part 1,for Phaco-Ex PRESS group,33 eyes underwent Ex-PRESS glaucoma mini-shunt implantation combined phacoemulsification,and 34 eyes underwent trabeculectomy combined with phacoemulsification in Phaco-Trab group.All the patients accepted slit-lamp microscopy,anterior segment optical coherence tomography(AS-OCT)and IVCM examinations.Indian bleb appearance grading scale(IBAGS),AS-OCT parameters(striping phenomenon: hyporeflective layer at the Tenon’s layer,which was presumed to be aqueous outflow channel)were collected.Using IVCM to scan the upper most,right most,bottom most,left most and highest part of filtering bleb,with 5 scanning sites in total.For each scan site,five non-overlapping epithelial layer pictures and one connective tissue picture were collected and IVCM parameters(average microcysts area,inflammatory cell density,connective tissue grade)were analyzed.Conjunctival tissue from highest part of filtering blebs from patients were scrabed and underwent Giemsa staining to identify the nature of hyperreflective dots revelaed by the IVCM.The follow-up timepoint were postoperative 2 weeks,1 month,3 months,6 months and 12 months.Results: At 12 months-postoperatively,accroding to IBAGS grading system,filtering bleb with height grade>2 and extension grade>2 had higher proportion in PhacoEx PRESS group(84.8% VS 47.1%,P<0.01;93.9% VS 50.0%,P<0.01).Phaco-Ex PRESS group also showed higher proportion in filtering bleb with avscular white bleb(36.4% VS 11.8%,P=0.02).Besides,when comparing two groups,Phaco-Ex PRESS group showed larger microcysts(P<0.001),lower inflammatory cell density(P<0.01)and lower connective tissue grade(P<0.01)at 12 months postoperatively.The microcysts area and hyperreflective dot density increased in each timepoint when compared with the baseline in Phaco-Ex PRSS group,while no significant change was found in connective tissue grade(P>0.05).While in Phaco-Trab group,decrease in microcyst area(P<0.05),increase in hyperreflective dot density(P<0.05)and connective tissue grade(P<0.05)were found.At 12 months-postoperatively,23 eyes(69.7%)from PhacoEx PRESS group showed striping phenomenon in AS-OCT,while only 13 eyes(38.2%)from Phaco-Trab group showed striping phenomenon.The Giemsa staining showed that the hyperreflective dot revealed by IVCM appeared to be monocyte and multinuclear inflammatory cell.The corelation between IVCM parameters showed that inflammatory cell density is negatively correlate with microcysts area(r=-0.664,P<0.001)and postively correlate with connective tissue grade(r=0.531,P<0.001),wihle the microcysts area is negatively correlate with connective tissue grade(r=-0.660,P<0.001)Conclusions: Phacoemulsification combined with Ex-PRESS glaucoma mini-shunt implantation has better filtering bleb morphology than phacotrabeculectomy.Filteing bleb of phacoemulsification combined with Ex-PRESS glaucoma mini-shunt implantation had larger microcysts area,lower hyperreflective dots and inflmmatory infiltration,as well as looser connective tissue.Part Ⅲ Purposes: The third part of the research is to correlate different parameters of slit lamp microscope and anterior segment optical coherence tomography(AS-OCT)examinations with IVCM.Methods: We involved the same patients as part 1 and part 2,with 67 eyes in total.We used slit-lamp microscope IBAGS grading system to evaluate the height,extension and vascularization of filtering bleb.We used AS-OCT to evaluate the total height,average thickness of bleb wall,cavity height and striping phenomenon(striping phenomenon: hyporeflective layer at the Tenon’s layer,which was presumed to be aqueous outflow channel).We used IVCM to detect average microcysts area,inflammatory cell density(which is confirmed to be neutrophil and macrophage in part 2)and connective tissue grade.We also analysed the correlation between different parameters of filtering bleb detected by three different machines mentioned above.Results: At 12 months postoperatively,1)according to IBAGS,the larger and higher the filtering bleb is,the larger microcysts area and lower inflammtory cell density can be found in IVCM(P<0.01).The higher grade of vascularization of filtering bleb is,the smaller microcysts area and higher inflammatory cell density can be seen(P<0.01).2)the bleb cavity height is negatively correlate with connective tissue grade(r=-0.512,P=0.01),but there is no correlation between total height of filtering bleb,bleb cavity height,average bleb wall thickness and inflammatory cell density.However,filtering bleb with striping phenomenon(35 eyes,52.25%)in AS-OCT,when compared with filtering bleb with no striping phenomenon(32 eyes,47.76%),showed larger average microcysts area and lower inflammatory cell density(P<0.01)in IVCM,while no difference was found in between two groups(P=0.14).For those filtering blebs with striping phenomenon at 12 months postoperatively,their microcysts area continously increased from 3 months postoperatively(postoperative 2 weeks 0.10 ± 0.05 VS postoperative 3 months 0.16 ± 0.08 VS postoperative 6 months 0.18 ± 0.09 VS postoperative 12 months 0.20±0.09,P<0.01),while their inflammatory cell density decreased from 6 months postoperatively(postoperative 2 weeks 124.08±94.01 VS postoperative 6 months 24.82±44.87 VS postoperative 12 months 18.75±53.19,P<0.05),their connective tissue grade decreased continuously from 3 months postoperatively(postoperative 2 weeks 1.50±0.70 VS postoperative 3 months 2.00±0.74 VS postoperative 6 months 2.00±0.60 VS postoperative 12 months 2.15±0.70,P<0.01).Conclusions: The extension,height and vascularization of filtering bleb(according to IBAGS grading system)as well as striping phenomenon in AS-OCT correlate well with microcysts area,inflammatory cell density and connective tissue grade in IVCM.IVCM can detect microscopic change of filtering bleb,serving as a better predictive method for filtering bleb function.