***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: 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 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 trabeculectomy and /or cataract extraction with intraocular lens implantation and uncontrolled glaucoma with intraocular pressure ( IOP ) ≥18 mm Hg and ≤40 mm Hg on maximum tolerated medical therapy . INTERVENTIONS Tube shunt ( 350-mm(2 ) Baerveldt glaucoma implant ) or trabeculectomy with mitomycin C ( [ MMC ] ; 0.4 mg/mL for 4 minutes ) . MAIN OUTCOME MEASURES IOP , visual acuity , use of supplemental medical therapy , and failure ( IOP > 21 mm Hg or not reduced by 20 % , IOP ≤5 mm Hg , reoperation for glaucoma , or loss of light perception vision ) . RESULTS A total of 212 eyes of 212 patients were enrolled , including 107 in the tube group and 105 in the trabeculectomy group . At 5 years , IOP ( mean ± SD ) was 14.4 ± 6.9 mm Hg in the tube group and 12.6 ± 5.9 mm Hg in the trabeculectomy group ( P = .12 ) . The number of glaucoma medications ( mean ± SD ) was 1.4 ± 1.3 in the tube group and 1.2 ± 1.5 in the trabeculectomy group ( P = .23 ) . The cumulative probability of failure during 5 years of follow-up was 29.8 % in the tube group and 46.9 % in the trabeculectomy group ( P = .002 ; hazard ratio = 2.15 ; 95 % confidence interval = 1.30 to 3.56 ) . The rate of reoperation for glaucoma was 9 % in the tube group and 29 % in the trabeculectomy group ( P = .025 ) . CONCLUSIONS Tube shunt surgery had a higher success rate  compared to trabeculectomy with MMC during 5 years of follow-up in the TVT Study . Both procedures were associated with similar IOP reduction and use of supplemental medical therapy at 5 years . Additional glaucoma surgery was needed more frequently after trabeculectomy with MMC than tube shunt placement In a prospect i ve r and omized clinical trial we compared the efficacy and safety of trabeculectomy and thermosclerostomy for the treatment of open angle glaucoma . Forty-eight eyes was treated by trabeculectomy and 50 eyes were treated by thermosclerostomy .  The mean follow-up period was 2.7 years . Thermosclerostomy lowered intraocular pressure about 3 mm Hg lower than trabeculectomy on the average . However , the percentage of eyes with pressures less than 22 mm Hg was not different for the two operations . The main difference between trabeculectomy and thermosclerostomy was the number of complications . Postoperative flat anterior chamber , decrease in visual acuity , cataract , hypotony , and thin bleb with late perforation or infection all occurred more frequently after thermosclerostomy . In conclusion , although trabeculectomy is slightly less effective than thermosclerostomy in lowering pressure , its relative freedom from complications make it is more desirable filtering operation The results of a r and omised , prospect i ve , multicentre trial of the management of primary open angle glaucoma are presented at up to five years ' follow up . Previously undiagnosed cases were selected with intraocular pressure of 26 mmHg or more on two occasions together with field loss characteristic of glaucoma . Analysis was performed on one eye selected at r and om from each of 99 patients .  Conventional medical treatment followed in unsuccessful cases by trabeculectomy ( group A ) was compared with trabeculectomy at diagnosis followed when necessary by supplementary medical therapy ( group B ) . The life expectancy of these glaucoma patients was found to be similar to that for the local population matched for age and sex . In group A after four years trabeculectomy had been performed in 53 % of eyes because medical management had failed to control the disease . The rate of operation was lower in those patients with intraocular pressure less than 31 mmHg and mild relative field loss ( 17 % at three years ) than in those with intraocular pressure greater than 30 mmHg and dense scotomas ( 75 % at three years ) . Early surgery provided much more stable control with fewer changes in treatment than in group A. The group mean intraocular pressure after trabeculectomy was 15.0 mmHg irrespective of the time of operation , and this was significantly lower than the intraocular pressure in those cases thought to be controlled on medical therapy alone at the end of the first year ( 20.8 mmHg ) . Early operation provided significantly better protection of visual field , and the extra loss of visual field with delayed operation occurred in the preoperative period . Changes in visual fields were not related to the use of miotics . There was no significant difference in the final visual acuity in the two groups , but six cases in group A lost central fixation because of progressive loss of visual field , and there were no such cases in group B. Cataract occurred in approximately 10 % of cases in both groups , but in group A this happened with only half the number of operations and at a shorter postoperative follow-up than in group B. It appears that in cases of primary open angle glaucoma of this severity the risk of delaying operation are significantly greater than those of performing trabeculectomy as the primary treatment PURPOSE To evaluate the impact of converting from Humphrey 24 - 2 full-threshold ( FT ) visual field ( VF ) testing to SITA-St and ard ( SS ) VF testing during the follow-up phase of a clinical trial . METHODS VF data were obtained from 243 patients in the Collaborative Initial Glaucoma Treatment Study ( CIGTS ) who had follow-up visits in 2004 .  FT and SS VF tests were performed in r and om order on the same day . RESULTS The average duration of the SS test  ( 6.3 minutes ) was shorter ( P < 0.0001 , paired t-test ) than the FT test ( 11.8 minutes ) . The mean deviation did not differ between SS and FT testing . A small difference was found in the pattern SD ( PSD ) ( P = 0.02 ) . The mean CIGTS score from the FT test ( 4.5 ) was significantly lower ( P < 0.0001 ) than the mean CIGTS score from the SS test ( 6.0 ) . Although the two tests yielded identical Glaucoma Hemifield Test ( GHT ) results in 179 patients ( 76 % ) , 16 patients had a  normal GHT result  on FT testing and an SS test result that was outside normal limits . Six patients had the reverse finding . The most significant factor associated with an increased ( positive ) difference between the CIGTS VF score generated from SS and FT testing was conducting the FT test first ( P < 0.0001 ) . CONCLUSIONS Although SS and FT testing yielded very similar mean deviation results , the CIGTS VF score and GHT differed between SS and FT tests . Changing the approach used to measuring a study 's primary VF outcome should be accompanied by a critical evaluation of the change 's impact Topical timolol given for the treatment or chronic simple glaucoma may cause unrecognised bronchospasm among elderly people . We recruited 80 patients aged over 60 years , who were without a history of airways disease and already used timolol , into a r and omised crossover study comparing the effects on spirometry and exercise tolerance of changing to betaxolol or dipivefrine therapy . Results showed an increase of 13 % and 8 % in mean peak flow rate and forced expiratory volume in 1 s ( FEV1 ) , respectively , when using betaxolol ; and of 14 % and 11 % when using dipivefrine . There was also improved exercise tolerance with both agents . More than a quarter of the patients showed at least a 15 % improvement in FEV1 when changed from timolol . Analysis of enrolment symptoms and response to nebulised salbutamol failed to produce a method of identifying these patients . Timolol may impair respiratory function and exercise tolerance of elderly patients even if they have no history of reversible airways disease PURPOSE To evaluate factors associated with visual field ( VF ) progression , using all available follow-up through 9 years after treatment initiation , in the Collaborative Initial Glaucoma Treatment Study ( CIGTS ) . DESIGN Longitudinal follow-up of participants enrolled in a r and omized clinical trial . PARTICIPANTS Six hundred seven newly diagnosed glaucoma patients . METHODS In a r and omized clinical trial , 607 subjects with newly diagnosed open-angle glaucoma initially were treated with either medication or trabeculectomy . After treatment initiation and early follow-up , subjects were evaluated clinical ly at 6-month intervals . Study participants in both arms of the CIGTS were treated aggressively in an effort to reduce intraocular pressure ( IOP ) to a level at or below a predetermined , eye-specific target pressure . Visual field progression was analyzed using repeated measures models . MAIN OUTCOME MEASURES Visual field progression , measured by Humphrey 24 - 2 full-threshold testing and assessed by the change in the mean deviation ( MD ) , and an indicator of substantial worsening of the VF ( MD decrease of > or =3 dB from baseline ) , assessed at each follow-up visit . RESULTS Follow-up indicated minimal change from baseline in each initial treatment group 's average MD . However , at the 8-year follow-up examination , substantial worsening ( > or =3 dB ) of MD from baseline was found in 21.3 % and 25.5 % of the initial surgery and initial medicine groups , respectively . The effect of initial treatment on subsequent VF loss was modified by time ( P<0.0001 ) , baseline MD ( P = 0.03 ) , and diabetes ( P = 0.01 ) . Initial surgery led to less VF progression than initial medicine in subjects with advanced VF loss at baseline , whereas subjects with diabetes had more VF loss over time if treated initially with surgery . CONCLUSIONS The CIGTS intervention protocol led to a lowering of IOP that persisted over time in both treatment groups . Progression in VF loss was seen in a subset , increasing to more than 20 % of the subjects . The findings regarding initial surgery being beneficial for subjects with more advanced VF loss at presentation , but detrimental for patients with diabetes , are noteworthy and warrant independent confirmation . FINANCIAL DISCLOSURE(S ) The author(s ) have no proprietary or commercial interest in any material s discussed in this article Computer-assisted perimetry was performed 6-monthly on patients entered into the Primary Treatment Trial using the 30 - 2 program . Those patients with a minimum of five 
    Output:
    
Primary surgery lowers IOP more than primary medication but is associated with more eye discomfort .
There is some evidence from two small trials in more severe OAG , that initial medication ( pilocarpine , now rarely used as first line medication ) is associated with more glaucoma progression than surgery .
Beyond five years , there is no evidence of a difference in the need for cataract surgery according to initial treatment .