human
***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 measure the 4-year risk of open-angle glaucoma ( OAG ) in a black population . DESIGN Population -based cohort study with 4 years of follow-up . SETTING Simple r and om sample of residents of Barbados , West Indies , aged 40 years or older . PARTICIPANTS A total of 3427 members of the cohort ( 85 % of those eligible ) . MAIN OUTCOME MEASURE Development of glaucoma visual field defects and optic disc damage , confirmed by automated perimetry , independent fundus photographic gradings , and st and ardized ophthalmologic examinations . RESULTS The 4-year risk of OAG in black participants was 2.2 % ( 95 % confidence interval , 1.7%-2.8 % ) , based on 67 newly developed cases of OAG . Incidence rates increased from 1.2 % at ages 40 to 49 years to 4.2 % at ages of 70 years or more , tending to be higher in men than women ( 2.7 % vs 1.9 % ) . About half of the incident cases were undiagnosed previously , and the rest were receiving OAG treatment . Of the 67 new cases of OAG , 32 had intraocular pressure of 21 mm Hg or less at baseline ( 1.2 % incidence ) and 35 had higher pressures ( 9 % incidence ) . Risk was highest among persons classified as having suspect OAG at baseline ( 26.1 % ) , followed by those with ocular hypertension ( 4.9 % ) and lowest in the remaining population ( 0.8 % ) . CONCLUSIONS This longitudinal study provides new information on OAG risk , as well as the first incidence measurement in a black population . Although intraocular pressure increased risk , about half of the new cases had baseline pressures of 21 mm Hg or less . Results substantiate the high OAG risk in the population of African origin , especially in older adults ; the relative role of intraocular pressure ; and the considerable underdetection of new disease after 4 years of follow-up OBJECTIVE To assess factors for progression in the Early Manifest Glaucoma Trial ( EMGT ) , including the effect of EMGT treatment . SETTING / PARTICIPANTS Two hundred fifty-five open-angle glaucoma patients r and omized to argon laser trabeculoplasty plus topical betaxolol or no immediate treatment ( 129 treated ; 126 controls ) and followed up every 3 months . METHODS Progression was determined by perimetric and photographic optic disc criteria . Patient-based risk of progression was evaluated using Cox proportional hazard regression models and was expressed as hazard ratios ( HR ) with 95 % confidence intervals ( 95 % CI ) . RESULTS After 6 years , 53 % of patients progressed . In multivariate analyses , progression risk was halved by treatment ( HR = 0.50 ; 95 % CI , 0.35 - 0.71 ) . Predictive baseline factors were higher intraocular pressure ( IOP ) ( ie , the higher the baseline IOP , the higher the risk ) , exfoliation , and having both eyes eligible ( each of the latter 2 factors doubled the risk ) , as well as worse mean deviation and older age . Progression risk decreased by about 10 % with each millimeter of mercury of IOP reduction from baseline to the first follow-up visit ( HR = 0.90 per millimeter of mercury decrease ; 95 % CI , 0.86 - 0.94 ) . The first IOP at that visit ( 3 months ' follow-up ) was also related to progression ( HR = 1.11 per millimeter of mercury higher ; 95 % CI , 1.06 - 1.17 ) , as was the mean IOP at follow-up ( HR = 1.13 per millimeter of mercury higher ; 95 % CI , 1.07 - 1.19 ) . The percent of patient follow-up visits with disc hemorrhages was also related to progression ( HR = 1.02 per percent higher ; 95 % CI , 1.01 - 1.03 ) . No other factors were identified . CONCLUSIONS Patients treated in the EMGT had half of the progression risk of control patients . The magnitude of initial IOP reduction was a major factor influencing outcome . Progression was also increased with higher baseline IOP , exfoliation , bilateral disease , worse mean deviation , and older age , as well as frequent disc hemorrhages during follow-up . Each higher ( or lower ) millimeter of mercury of IOP on follow-up was associated with an approximate 10 % increased ( or decreased ) risk of progression Anterior chamber fluorophotometry ( Fluorotron Master II , Coherent , Palo Alto , Calif. ) was used to investigate the influence of 1,3,7-trimethylxanthin on the circadian rhythm of aqueous humor secretion in two age- , race- and sex-matched groups of healthy volunteers . In ten males and ten females ( mean age 27 years ) , aqueous humor secretion was measured over 24 h at : 0800 , 0900 , 1000 - 1400 , 1500 , 1600 - 2000 , 2100 , 2200 - 0200 , 0300 , and 0400 hours . Flow was calculated using the Yablonsky protocol of Fluorotron Master II . In group I all volunteers received about 800 mg trimethylxanthin in the form of caffeinated coffee between 2200 and 2300 hours . In group II volunteers went to sleep at 2300 hours . Sleep was only interrupted for measurements . During the daytime the mean aqueous humor flow was the same in both groups ( 0800 to 2200 hours ) ( Student 's t-test ) : Group I ( n = 10 ) RA 2.27 + /- 0.70 microliters/min LA 2.25 + /- 0.74 microliters/min Group II ( n = 10 ) RA 2.23 + /- 0.73 microliters/min LA 2.06 + /- 0.64 microliters/min During the night the mean aqueous humor flow decreased in both groups ( 0200 to 0400 hours ) : Group I : RA 1.99 + /- 0.74 microliters/min delta flow = -12 % LA 1.93 + /- 0.75 microliters/min Group II : RA 0.97 + /- 0.50 microliters/min delta flow = -56 % LA 0.97 + /- 0.48 microliters/min The difference between groups was statistically significant ( P = 0.01 , t-test for unpaired sample s ) . There was no significant change in mean aqueous humor flow between the daytime vs night in group I ( P < 0.5 ) . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND The Ocular Hypertension Treatment Study ( OHTS ) has shown that topical ocular hypotensive medication is effective in delaying or preventing the onset of primary open-angle glaucoma ( POAG ) in individuals with elevated intraocular pressure ( ocular hypertension ) and no evidence of glaucomatous damage . OBJECTIVE To describe baseline demographic and clinical factors that predict which participants in the OHTS developed POAG . METHODS Baseline demographic and clinical data were collected prior to r and omization except for corneal thickness measurements , which were performed during follow-up . Proportional hazards models were used to identify factors that predicted which participants in the OHTS developed POAG . RESULTS In univariate analyses , baseline factors that predicted the development of POAG included older age , race ( African American ) , sex ( male ) , larger vertical cup-disc ratio , larger horizontal cup-disc ratio , higher intraocular pressure , greater Humphrey visual field pattern st and ard deviation , heart disease , and thinner central corneal measurement . In multivariate analyses , baseline factors that predicted the development of POAG included older age , larger vertical or horizontal cup-disc ratio , higher intraocular pressure , greater pattern st and ard deviation , and thinner central corneal measurement . CONCLUSIONS Baseline age , vertical and horizontal cup-disc ratio , pattern st and ard deviation , and intraocular pressure were good predictors for the onset of POAG in the OHTS . Central corneal thickness was found to be a powerful predictor for the development of POAG PURPOSE To determine the effect of caffeine on microcirculation in the human ocular fundus . METHODS The microcirculation in the ocular fundus of 10 healthy volunteers ( 10 eyes ) was studied using a laser speckle tissue circulation analyzer . Caffeine or placebo ( 100 mg ) was administered orally in a double-masked manner . Square blur rate ( SBR ) , a quantitative index of blood flow velocity , was measured in a temporal site of the optic nerve head ( ONH ) free of surface vessels and in a middle site of the choroid-retina between the ONH and macula . Intraocular pressure ( IOP ) , blood pressure ( BP ) , pulse rate ( PR ) , and central critical fusion frequency ( CFF ) were also measured . These parameters were measured before and for 2 hours after administration . The area under curve ( AUC ) of SBR was calculated for each area . Ocular perfusion pressure ( OPP ) was also calculated from BP and IOP . RESULTS The time-course of change in SBR value showed much individual difference . Caffeine decreased the AUC of SBR in the ONH ( P = .0218 ) as well as in the choroid-retina ( P = .0469 ) significantly . IOP , mean BP , PR , OPP , and central CFF did not change significantly . CONCLUSIONS These results suggest that caffeine may increase blood vessel resistance and decrease blood flow in the human ONH and choroid-retina This study examined the effects of caffeinated coffee on the  intraocular pressure of nonglaucomatous subjects . Subjects were r and omly assigned to receive each of three treatments : caffeinated coffee , hot water , and no fluid . All subjects were given the three treatment conditions over 3 days . The study revealed that intraocular pressure after ingesting caffeinated coffee was significantly higher than after receiving the other two treatment conditions . It was further found that increased intraocular pressure was maintained at significant levels over a 3-hour period . No significant changes were found in the pulse rate , and findings on blood pressure were inconclusive In a study lasting 16 months , Timolol was tested on 57 eyes of a group of selected patients with open-angle glaucoma . Patients whose IOP could not be stabilized with the 0.25 % solution were treated with 0.5 % drops twice a day . In five separate cases , where regulation was inadequate , pilocarpine 2 % twice a day was prescribed in addition . At the end of 16 months ' treatment pressure had been lowered to a statistically highly significant degree in 66 % of the patients . While the degree of regulation in the remainder was not statistically sifnificant , most of them were adequately stabilized . Further , following stabilization with Timolol , 42 % of the patients were subjected to tolerance tests under constant conditions ( darkness test , water test , coffee and tea tolerance ) and their 6.00 a.m.values were measured . While good pressure levels were recorded in the tolerance tests , the early-morning IOP rose to critical threshold levels in some patients . However , during the entire period of observation visual fields and optic disk findings remained unaltered in all cases . Only a few cases were subjective and /or objective side-effects seen . Ten percent of those patients who had been treated previously required new glasses ( + 0,5 to + 1 D over the previous correction ) Aims : To evaluate the influence of central corneal thickness ( CCT ) on intraocular pressure ( IOP ) measurements made with the Goldmann applanation tonometer ( GAT ) , Tono-Pen XL , ocular blood flow tonograph ( OBF ) , and Canon TX-10 non-contact tonometer ( NCT ) . Methods : CCT was recorded for either eye ( r and omly selected ) of each of 105 untreated patients with ocular hypertension and glaucoma attending the glaucoma research unit at Moorfields Eye Hospital . For each of the selected eyes , IOP was measured with the GAT ( two observers ) , Tono-Pen , OBF , and NCT in a r and omised order . The relation of measured IOP and of inter-tonometer differences with CCT and subject age was explored by linear regression analysis . Results : A significant association between measured IOP and CCT was found with each instrument . The change in measured IOP for a 10 μm increase in CCT was 0.28 , 0.31 , 0.38 , and 0.46 for the GAT , Tono-Pen , OBF , and NCT , respectively ( all p⩽0.05 ) . There was a significant association between the NCT/GAT differences and CCT , with a tendency of NCT to overestimate GAT in eyes with thicker corneas . There was a significant association between GAT/Tono-Pen and OBF/Tono-Pen differences and age , with a tendency of GAT and OBF to overestimate the Tono-Pen in eyes of older subjects . Conclusion : IOP measurement by all four methods is affected by CCT . The NCT is affected by CCT significantly more than the GAT . Subject age has a differential effect on the IOP measurements made by the GAT and OBF compared to the Tono-Pen BACKGROUND The prevalence of glaucoma is higher in African American individuals than in white individuals . OBJECTIVE To report the safety and efficacy of topical ocular hypotensive medication in delaying or preventing the onset of primary open 
    Output:
    
agent
***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 measure the 4-year risk of open-angle glaucoma ( OAG ) in a black population . DESIGN Population -based cohort study with 4 years of follow-up . SETTING Simple r and om sample of residents of Barbados , West Indies , aged 40 years or older . PARTICIPANTS A total of 3427 members of the cohort ( 85 % of those eligible ) . MAIN OUTCOME MEASURE Development of glaucoma visual field defects and optic disc damage , confirmed by automated perimetry , independent fundus photographic gradings , and st and ardized ophthalmologic examinations . RESULTS The 4-year risk of OAG in black participants was 2.2 % ( 95 % confidence interval , 1.7%-2.8 % ) , based on 67 newly developed cases of OAG . Incidence rates increased from 1.2 % at ages 40 to 49 years to 4.2 % at ages of 70 years or more , tending to be higher in men than women ( 2.7 % vs 1.9 % ) . About half of the incident cases were undiagnosed previously , and the rest were receiving OAG treatment . Of the 67 new cases of OAG , 32 had intraocular pressure of 21 mm Hg or less at baseline ( 1.2 % incidence ) and 35 had higher pressures ( 9 % incidence ) . Risk was highest among persons classified as having suspect OAG at baseline ( 26.1 % ) , followed by those with ocular hypertension ( 4.9 % ) and lowest in the remaining population ( 0.8 % ) . CONCLUSIONS This longitudinal study provides new information on OAG risk , as well as the first incidence measurement in a black population . Although intraocular pressure increased risk , about half of the new cases had baseline pressures of 21 mm Hg or less . Results substantiate the high OAG risk in the population of African origin , especially in older adults ; the relative role of intraocular pressure ; and the considerable underdetection of new disease after 4 years of follow-up OBJECTIVE To assess factors for progression in the Early Manifest Glaucoma Trial ( EMGT ) , including the effect of EMGT treatment . SETTING / PARTICIPANTS Two hundred fifty-five open-angle glaucoma patients r and omized to argon laser trabeculoplasty plus topical betaxolol or no immediate treatment ( 129 treated ; 126 controls ) and followed up every 3 months . METHODS Progression was determined by perimetric and photographic optic disc criteria . Patient-based risk of progression was evaluated using Cox proportional hazard regression models and was expressed as hazard ratios ( HR ) with 95 % confidence intervals ( 95 % CI ) . RESULTS After 6 years , 53 % of patients progressed . In multivariate analyses , progression risk was halved by treatment ( HR = 0.50 ; 95 % CI , 0.35 - 0.71 ) . Predictive baseline factors were higher intraocular pressure ( IOP ) ( ie , the higher the baseline IOP , the higher the risk ) , exfoliation , and having both eyes eligible ( each of the latter 2 factors doubled the risk ) , as well as worse mean deviation and older age . Progression risk decreased by about 10 % with each millimeter of mercury of IOP reduction from baseline to the first follow-up visit ( HR = 0.90 per millimeter of mercury decrease ; 95 % CI , 0.86 - 0.94 ) . The first IOP at that visit ( 3 months ' follow-up ) was also related to progression ( HR = 1.11 per millimeter of mercury higher ; 95 % CI , 1.06 - 1.17 ) , as was the mean IOP at follow-up ( HR = 1.13 per millimeter of mercury higher ; 95 % CI , 1.07 - 1.19 ) . The percent of patient follow-up visits with disc hemorrhages was also related to progression ( HR = 1.02 per percent higher ; 95 % CI , 1.01 - 1.03 ) . No other factors were identified . CONCLUSIONS Patients treated in the EMGT had half of the progression risk of control patients . The magnitude of initial IOP reduction was a major factor influencing outcome . Progression was also increased with higher baseline IOP , exfoliation , bilateral disease , worse mean deviation , and older age , as well as frequent disc hemorrhages during follow-up . Each higher ( or lower ) millimeter of mercury of IOP on follow-up was associated with an approximate 10 % increased ( or decreased ) risk of progression Anterior chamber fluorophotometry ( Fluorotron Master II , Coherent , Palo Alto , Calif. ) was used to investigate the influence of 1,3,7-trimethylxanthin on the circadian rhythm of aqueous humor secretion in two age- , race- and sex-matched groups of healthy volunteers . In ten males and ten females ( mean age 27 years ) , aqueous humor secretion was measured over 24 h at : 0800 , 0900 , 1000 - 1400 , 1500 , 1600 - 2000 , 2100 , 2200 - 0200 , 0300 , and 0400 hours . Flow was calculated using the Yablonsky protocol of Fluorotron Master II . In group I all volunteers received about 800 mg trimethylxanthin in the form of caffeinated coffee between 2200 and 2300 hours . In group II volunteers went to sleep at 2300 hours . Sleep was only interrupted for measurements . During the daytime the mean aqueous humor flow was the same in both groups ( 0800 to 2200 hours ) ( Student 's t-test ) : Group I ( n = 10 ) RA 2.27 + /- 0.70 microliters/min LA 2.25 + /- 0.74 microliters/min Group II ( n = 10 ) RA 2.23 + /- 0.73 microliters/min LA 2.06 + /- 0.64 microliters/min During the night the mean aqueous humor flow decreased in both groups ( 0200 to 0400 hours ) : Group I : RA 1.99 + /- 0.74 microliters/min delta flow = -12 % LA 1.93 + /- 0.75 microliters/min Group II : RA 0.97 + /- 0.50 microliters/min delta flow = -56 % LA 0.97 + /- 0.48 microliters/min The difference between groups was statistically significant ( P = 0.01 , t-test for unpaired sample s ) . There was no significant change in mean aqueous humor flow between the daytime vs night in group I ( P < 0.5 ) . ( ABSTRACT TRUNCATED AT 250 WORDS BACKGROUND The Ocular Hypertension Treatment Study ( OHTS ) has shown that topical ocular hypotensive medication is effective in delaying or preventing the onset of primary open-angle glaucoma ( POAG ) in individuals with elevated intraocular pressure ( ocular hypertension ) and no evidence of glaucomatous damage . OBJECTIVE To describe baseline demographic and clinical factors that predict which participants in the OHTS developed POAG . METHODS Baseline demographic and clinical data were collected prior to r and omization except for corneal thickness measurements , which were performed during follow-up . Proportional hazards models were used to identify factors that predicted which participants in the OHTS developed POAG . RESULTS In univariate analyses , baseline factors that predicted the development of POAG included older age , race ( African American ) , sex ( male ) , larger vertical cup-disc ratio , larger horizontal cup-disc ratio , higher intraocular pressure , greater Humphrey visual field pattern st and ard deviation , heart disease , and thinner central corneal measurement . In multivariate analyses , baseline factors that predicted the development of POAG included older age , larger vertical or horizontal cup-disc ratio , higher intraocular pressure , greater pattern st and ard deviation , and thinner central corneal measurement . CONCLUSIONS Baseline age , vertical and horizontal cup-disc ratio , pattern st and ard deviation , and intraocular pressure were good predictors for the onset of POAG in the OHTS . Central corneal thickness was found to be a powerful predictor for the development of POAG PURPOSE To determine the effect of caffeine on microcirculation in the human ocular fundus . METHODS The microcirculation in the ocular fundus of 10 healthy volunteers ( 10 eyes ) was studied using a laser speckle tissue circulation analyzer . Caffeine or placebo ( 100 mg ) was administered orally in a double-masked manner . Square blur rate ( SBR ) , a quantitative index of blood flow velocity , was measured in a temporal site of the optic nerve head ( ONH ) free of surface vessels and in a middle site of the choroid-retina between the ONH and macula . Intraocular pressure ( IOP ) , blood pressure ( BP ) , pulse rate ( PR ) , and central critical fusion frequency ( CFF ) were also measured . These parameters were measured before and for 2 hours after administration . The area under curve ( AUC ) of SBR was calculated for each area . Ocular perfusion pressure ( OPP ) was also calculated from BP and IOP . RESULTS The time-course of change in SBR value showed much individual difference . Caffeine decreased the AUC of SBR in the ONH ( P = .0218 ) as well as in the choroid-retina ( P = .0469 ) significantly . IOP , mean BP , PR , OPP , and central CFF did not change significantly . CONCLUSIONS These results suggest that caffeine may increase blood vessel resistance and decrease blood flow in the human ONH and choroid-retina This study examined the effects of caffeinated coffee on the  intraocular pressure of nonglaucomatous subjects . Subjects were r and omly assigned to receive each of three treatments : caffeinated coffee , hot water , and no fluid . All subjects were given the three treatment conditions over 3 days . The study revealed that intraocular pressure after ingesting caffeinated coffee was significantly higher than after receiving the other two treatment conditions . It was further found that increased intraocular pressure was maintained at significant levels over a 3-hour period . No significant changes were found in the pulse rate , and findings on blood pressure were inconclusive In a study lasting 16 months , Timolol was tested on 57 eyes of a group of selected patients with open-angle glaucoma . Patients whose IOP could not be stabilized with the 0.25 % solution were treated with 0.5 % drops twice a day . In five separate cases , where regulation was inadequate , pilocarpine 2 % twice a day was prescribed in addition . At the end of 16 months ' treatment pressure had been lowered to a statistically highly significant degree in 66 % of the patients . While the degree of regulation in the remainder was not statistically sifnificant , most of them were adequately stabilized . Further , following stabilization with Timolol , 42 % of the patients were subjected to tolerance tests under constant conditions ( darkness test , water test , coffee and tea tolerance ) and their 6.00 a.m.values were measured . While good pressure levels were recorded in the tolerance tests , the early-morning IOP rose to critical threshold levels in some patients . However , during the entire period of observation visual fields and optic disk findings remained unaltered in all cases . Only a few cases were subjective and /or objective side-effects seen . Ten percent of those patients who had been treated previously required new glasses ( + 0,5 to + 1 D over the previous correction ) Aims : To evaluate the influence of central corneal thickness ( CCT ) on intraocular pressure ( IOP ) measurements made with the Goldmann applanation tonometer ( GAT ) , Tono-Pen XL , ocular blood flow tonograph ( OBF ) , and Canon TX-10 non-contact tonometer ( NCT ) . Methods : CCT was recorded for either eye ( r and omly selected ) of each of 105 untreated patients with ocular hypertension and glaucoma attending the glaucoma research unit at Moorfields Eye Hospital . For each of the selected eyes , IOP was measured with the GAT ( two observers ) , Tono-Pen , OBF , and NCT in a r and omised order . The relation of measured IOP and of inter-tonometer differences with CCT and subject age was explored by linear regression analysis . Results : A significant association between measured IOP and CCT was found with each instrument . The change in measured IOP for a 10 μm increase in CCT was 0.28 , 0.31 , 0.38 , and 0.46 for the GAT , Tono-Pen , OBF , and NCT , respectively ( all p⩽0.05 ) . There was a significant association between the NCT/GAT differences and CCT , with a tendency of NCT to overestimate GAT in eyes with thicker corneas . There was a significant association between GAT/Tono-Pen and OBF/Tono-Pen differences and age , with a tendency of GAT and OBF to overestimate the Tono-Pen in eyes of older subjects . Conclusion : IOP measurement by all four methods is affected by CCT . The NCT is affected by CCT significantly more than the GAT . Subject age has a differential effect on the IOP measurements made by the GAT and OBF compared to the Tono-Pen BACKGROUND The prevalence of glaucoma is higher in African American individuals than in white individuals . OBJECTIVE To report the safety and efficacy of topical ocular hypotensive medication in delaying or preventing the onset of primary open 
    Output:
    