***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: PURPOSE To determine if intraocular pressure plays a part in the pathogenic process of normal-tension glaucoma . METHODS One eye of each eligible subject was r and omized either to be untreated as a control or to have intraocular pressure lowered by 30 % from baseline . Eyes were r and omized if they met criteria for diagnosis of normal-tension glaucoma and showed documented progression or high-risk field defects that threatened fixation or the appearance of a new disk hemorrhage . The clinical course ( visual field and optic disk ) of the group with lowered intraocular pressure was compared with the clinical course when intraocular pressure remained at its spontaneous untreated level . RESULTS One hundred-forty eyes of 140 patients were used in this study . Sixty-one were in the treatment group , and 79 were untreated controls . Twenty-eight ( 35 % ) of the control eyes and 7 ( 12 % ) of the treated eyes reached end points ( specifically defined criteria of glaucomatous optic disk progression or visual field loss ) . An overall survival analysis showed a statistically significant difference between the two groups ( P < .0001 ) . The mean survival time + /-SD of the treated group was 2,688 + /- 123 days and for the control group , 1,695 + /- 143 days . Of 34 cataracts developed during the study , 11 ( 14 % ) occurred in the control group and 23 ( 38 % ) in the treated group ( P = .0075 ) , with the highest incidence in those whose treatment included filtration surgery . CONCLUSIONS Intraocular pressure is part of the pathogenic process in normal-tension glaucoma . Therapy that is effective in lowering intraocular pressure and free of adverse effects would be expected to be beneficial in patients who are at risk of disease progression PURPOSE To compare 2 frequently used aqueous shunts for the treatment of glaucoma . DESIGN International , multicenter , r and omized trial . PARTICIPANTS Patients aged 18 years or older with uncontrolled glaucoma despite maximum tolerated medical therapy , many of whom had failed or were at high risk of failing trabeculectomy . METHODS Eligible patients were r and omized to receive an Ahmed-FP7 valve implant ( New World Medical , Inc , Rancho Cucamonga , CA ) or a Baerveldt-350 implant ( Abbott Medical Optics , Inc , Santa Ana , CA ) using a st and ardized surgical technique . MAIN OUTCOME MEASURES The primary outcome was failure , defined as intraocular pressure ( IOP ) outside the target range ( 5 - 18 mmHg ) or reduced < 20 % from baseline for 2 consecutive visits after 3 months , severe vision loss , or de novo glaucoma surgery . Secondary outcomes measures included IOP , medication use , visual acuity , complications , and interventions . RESULTS A total of 238 patients were r and omized ; 124 received the Ahmed-FP7 implant , and 114 received the Baerveldt-350 implant . Baseline characteristics were similar between groups . Mean preoperative IOP was 31.4±10.8 mmHg on 3.1±1.0 glaucoma medications . At 5 years , the cumulative failure rate was 53 % in the Ahmed group and 40 % in the Baerveldt group ( P = 0.04 ) . The main reason for failure in both groups was high IOP , and the cumulative de novo glaucoma reoperation rate was 18 % in the Ahmed group and 11 % in the Baerveldt group ( P = 0.22 ) . Hypotony result ed in failure in 5 patients ( 4 % ) in the Baerveldt group compared with none in the Ahmed group ( P = 0.02 ) . Mean IOP was 16.6±5.9 mmHg in the Ahmed group ( 47 % reduction ) and 13.6±5.0 mmHg in the Baerveldt group ( 57 % reduction , P = 0.001 ) . Mean medication use was 1.8±1.5 mmHg in the Ahmed group ( 44 % reduction ) and 1.2±1.3 mmHg in the Baerveldt group ( 61 % reduction , P = 0.03 ) . The 2 groups had similar complication rates ( Ahmed 63 % , Baerveldt 69 % ) and intervention rates ( Ahmed 41 % , Baerveldt 41 % ) . Most complications were transient , and most interventions were slit-lamp procedures . CONCLUSIONS Both implants were effective in reducing IOP and the need for glaucoma medications . The Baerveldt group had a lower failure rate and a lower IOP on fewer medications than the Ahmed group , but had a small risk of hypotony that was not seen in the Ahmed group OBJECTIVE To provide the results of the Early Manifest Glaucoma Trial , which compared the effect of immediately lowering the intraocular pressure ( IOP ) , vs no treatment or later treatment , on the progression of newly detected open-angle glaucoma . DESIGN R and omized clinical trial . PARTICIPANTS Two hundred fifty-five patients aged 50 to 80 years ( median , 68 years ) with early glaucoma , visual field defects ( median mean deviation , -4 dB ) , and a median IOP of 20 mm Hg , mainly identified through a population screening . Patients with an IOP greater than 30 mm Hg or advanced visual field loss were ineligible . INTERVENTIONS Patients were r and omized to either laser trabeculoplasty plus topical betaxolol hydrochloride ( n = 129 ) or no initial treatment ( n = 126 ) . Study visits included Humphrey Full Threshold 30 - 2 visual field tests and tonometry every 3 months , and optic disc photography every 6 months . Decisions regarding treatment were made jointly with the patient when progression occurred and thereafter . MAIN OUTCOME MEASURES Glaucoma progression was defined by specific visual field and optic disc outcomes . Criteria for perimetric progression were computer based and defined as the same 3 or more test point locations showing significant deterioration from baseline in glaucoma change probability maps from 3 consecutive tests . Optic disc progression was determined by masked grade rs using flicker chronoscopy plus side-by-side photogradings . RESULTS After a median follow-up period of 6 years ( range , 51 - 102 months ) , retention was excellent , with only 6 patients lost to follow-up for reasons other than death . On average , treatment reduced the IOP by 5.1 mm Hg or 25 % , a reduction maintained throughout follow-up . Progression was less frequent in the treatment group ( 58/129 ; 45 % ) than in controls ( 78/126 ; 62 % ) ( P = .007 ) and occurred significantly later in treated patients . Treatment effects were also evident when stratifying patients by median IOP , mean deviation , and age as well as exfoliation status . Although patients reported few systemic or ocular conditions , increases in clinical nuclear lens opacity gradings were associated with treatment ( P = .002 ) . CONCLUSIONS The Early Manifest Glaucoma Trial is the first adequately powered r and omized trial with an untreated control arm to evaluate the effects of IOP reduction in patients with open-angle glaucoma who have elevated and normal IOP . Its intent-to-treat analysis showed considerable beneficial effects of treatment that significantly delayed progression . Whereas progression varied across patient categories , treatment effects were present in both older and younger patients , high- and normal-tension glaucoma , and eyes with less and greater visual field loss Purpose The purpose of this study was to assess the effects of intraoperative mitomycin-C ( MMC ) on the function of Baerveldt glaucoma implants in rabbits . Methods Bilateral implantations of 200 mm2 Baerveldt drainage devices were performed in 30 normal albino rabbits . One eye , r and omly selected , received intraoperative application of MMC at the site of the implant plate for 5 min , via a 6 x 4 x 2 mm cellulose sponge saturated with 0.5 mg/ml of MMC . The opposite eye served as a control . MMC-treated and control eyes ( five animals each group ) were compared for intraocular pressure ( IOP ) , resistance to flow , flow rates through the implant and histopathological findings at 2 , 4 , 6 , 12 , and 24 weeks postoperatively . Resistance to flow and flow rates through the implants were studied after opening the cornea and connecting the drain tube to a micromanometric system . Results Preoperative IOP did not differ between groups . MMC-treated eyes had lower levels of IOP than did controls at all postoperative times . The differences in IOP were statistically significant up to 8 weeks postoperatively . Resistance to flow was lower in MMC-treated eyes at all times studied , but the differences were statistically significant only at the time points of 2 , 4 , and 6 weeks . Flow rates through the implant bleb were always higher in MMC-treated eyes , and statistically significant differences were seen at 2 , 4 , 6 , and 24 weeks . Histopathologically , MMC-treated eyes had thinner implant capsules with delayed maturation and less inflammatory infiltrate . Conclusion MMC causes lower IOP and higher perfusion rates through the implant capsule at 2 , 4 , and 6 weeks postoperatively . Wound dehiscence , bleb leaks , and extraocular muscle injury were observed only in MMC-treated eyes PURPOSE Previous studies have suggested that primary double-plate Molteno implantation may be beneficial . Therefore , the authors performed a r and omized clinical trial to evaluate the relative effectiveness and safety of single- versus double-plate Molteno implantation . METHODS From March 1988 to February 1990 , 132 patients who underwent Molteno implantation for medically uncontrollable non-neovascular glaucomas in aphakia or pseudophakia were r and omly assigned to receive either single- or double-plate implants . RESULTS The 1- and 2-year life-table success rates ( success [ survival ] defined as 6 mmHg < or = final intraocular pressure [ IOP ] < or = 21 mmHg without additional glaucoma surgery or devastating complication ) were 55 % and 46 % with single-plate implantation and 86 % and 71 % with double-plate implantation , respectively . The final postoperative visual acuities were within one line of the preoperative visual acuities or had improved in 73 % and 80 % of patients , respectively . Choroidal hemorrhages and /or effusions , corneal decompensation , flat anterior chambers , and phthisis bulbi were more common in the patients who had undergone double-plate Molteno implantation ; however , transient elevations of IOP during the first few postoperative months were more common in the patients who had undergone single-plate Molteno implantation . CONCLUSIONS Double-plate Molteno implantation more frequently affords IOP control than single-plate Molteno implantation ; however , double plates are associated with greater risks of choroidal hemorrhages and /or effusions , corneal decompensation , flat anterior chambers , and phthisis bulbi PURPOSE The Ahmed Baerveldt Comparison ( ABC ) Study compares the long-term outcomes and complications of the Ahmed glaucoma valve ( AGV ; model FP7 ; New World Medical , Los Ranchos , CA ) and the Baerveldt glaucoma implant ( BGI ; model 101 - 350 ; Abbott Medical Optics , Abbott Park , IL ) . DESIGN Multicenter , r and omized , controlled clinical trial . PARTICIPANTS Two hundred seventy-six glaucoma patients at 16 clinical centers worldwide who were 18 to 85 years of age with inadequately controlled intraocular pressure ( IOP ; ≥18 mmHg ) in whom placement of an aqueous shunt was planned . METHODS Study patients were r and omized to undergo implantation of an AGV or a BGI .  MAIN OUTCOME MEASURES Failure , defined as IOP > 21 mmHg or not reduced by 20 % less than baseline or IOP ≤5 mmHg ( 2 consecutive visits after 3 months ) , additional glaucoma surgery , removal of the implant , or loss of light perception vision . RESULTS A total of 276 patients were enrolled between October 2006 and April 2008 , including 143 in the AGV group and 133 in the BGI group . The mean age±st and ard deviation ( SD ) of patients enrolled was 63±14 years , and 52 % were male . The mean baseline IOP±SD was 31.5±11.8 mmHg . Except for a 13 % higher prevalence of hypertension in the AGV group , no significant differences in baseline demographic or ocular characteristics were observed between the study groups . Intraoperative complications occurred in 11 ( 8 % ) patients in the AGV group and in 16 ( 12 % ) patients in the BGI group ( P = 0.31 ) . CONCLUSIONS The ABC Study should yield valuable prospect i ve data comparing 2 commonly used aqueous shunts in clinical practice PURPOSE To report 5-year treatment outcomes in the Tube Versus Trabeculectomy ( TVT ) Study . DESIGN Multicenter r and omized clinical trial . METHODS SETTING S Seventeen clinical centers . STUDY POPULATION Patients 18 to 85 years of age who had previous trabeculect 
    Output:
    
Information was insufficient to conclude whether there are differences between aqueous shunts and trabeculectomy for glaucoma treatment .
While the Baerveldt implant may lower IOP more than the Ahmed implant , the evidence was of moderate-certainty and it is unclear whether the difference in IOP reduction is clinical ly significant .
Overall , methodology and data quality among existing r and omized controlled trials of aqueous shunts was heterogeneous across studies , and there are no well-justified or widely accepted generalizations about the superiority of one surgical procedure or device over another