***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 assess the incremental cost and cost-effectiveness of continuous and discontinuous regimens of bevacizumab ( Avastin ) and ranibizumab ( Lucentis ) for neovascular age-related macular degeneration ( nAMD ) from a UK National Health Service ( NHS ) perspective . Design A within-trial cost-utility analysis with a 2-year time horizon , based on a multicentre factorial , non-inferiority r and omised controlled trial . Setting 23 hospital ophthalmology clinics . Participants 610 patients aged ≥50 years with untreated nAMD in the study eye . Interventions 0.5 mg ranibizumab or 1.25 mg bevacizumab given continuously ( monthly ) or discontinuously ( as-needed ) for 2 years . Main outcome measures Quality -adjusted life-years ( QALYs ) . Results Total 2-year costs ranged from £ 3002/patient ( $ 4700 ; 95 % CI £ 2601 to £ 3403 ) for discontinuous bevacizumab to £ 18 590/patient ( $ 29 106 ; 95 % CI £ 18 258 to £ 18 922 ) for continuous ranibizumab . Ranibizumab was significantly more costly  than bevacizumab for both continuous ( + £ 14 989/patient ( $ 23 468 ) ; 95 % CI £ 14 522 to £ 15 456 ; p<0.001 ) and discontinuous treatment ( + £ 8498 ( $ 13 305 ) ; 95 % CI £ 7700 to £ 9295 ; p<0.001 ) , with negligible difference in QALYs . Continuous ranibizumab would only be cost-effective compared with continuous bevacizumab if the NHS were willing to pay £ 3.5 million ( $ 5.5 million ) per additional QALY gained . Patients receiving continuous bevacizumab  accrued higher total costs ( + £ 599 ( $ 938 ) ; 95 % CI £ 91 to £ 1107 ; p=0.021 ) than those receiving discontinuous bevacizumab , but also accrued non-significantly more QALYs ( + 0.020 ; 95 % CI −0.032 to 0.071 ; p=0.452 ) . Continuous bevacizumab therefore cost £ 30 220 ( $ 47 316 ) per QALY gained versus discontinuous bevacizumab . However , bootstrapping demonstrated that if the NHS is willing to pay £ 20 000/QALY gained , there is a 37 % chance that continuous bevacizumab  is cost-effective versus discontinuous bevacizumab . Conclusions Ranibizumab  is not cost-effective compared with bevacizumab , being substantially more costly and producing little or no QALY gain . Discontinuous bevacizumab is likely to be the most cost-effective of the four treatment strategies evaluated in this UK trial , although there is a 37 % chance that continuous bevacizumab is cost-effective . Trial registration number IS RCT N92166560 OBJECTIVE To describe effects of ranibizumab and bevacizumab when administered monthly or as needed for 2 years and to describe the impact of switching to as-needed treatment after 1 year of monthly treatment . DESIGN Multicenter , r and omized clinical trial . PARTICIPANTS Patients ( n = 1107 ) who were followed up during year 2 among 1185 patients with neovascular age-related macular degeneration who were enrolled in the clinical trial . INTERVENTIONS At enrollment , patients were assigned to 4 treatment groups defined by drug ( ranibizumab or bevacizumab ) and dosing regimen ( monthly or as needed ) . At 1 year , patients initially assigned to monthly treatment were reassigned r and omly to monthly or as-needed treatment , without changing the drug assignment . MAIN OUTCOME MEASURES Mean change in visual acuity . RESULTS Among patients following the same regimen for 2 years , mean gain in visual acuity was similar for both drugs ( bevacizumab-ranibizumab difference , -1.4 letters ; 95 % confidence interval [ CI ] , -3.7 to 0.8 ; P = 0.21 ) . Mean gain was greater for monthly than for as-needed treatment ( difference , -2.4 letters ; 95 % CI , -4.8 to -0.1 ; P = 0.046 ) . The proportion without fluid ranged from 13.9 % in the bevacizumab-as-needed group to 45.5 % in the ranibizumab monthly group ( drug , P = 0.0003 ; regimen , P < 0.0001 ) . Switching from monthly to as-needed treatment result ed in greater mean decrease in vision during year 2 ( -2.2 letters ; P = 0.03 ) and a lower proportion without fluid ( -19 % ; P < 0.0001 ) . Rates of death and arteriothrombotic events were similar for both drugs ( P > 0.60 ) . The proportion of patients with 1 or more systemic serious adverse events was higher with bevacizumab than ranibizumab ( 39.9 % vs. 31.7 % ; adjusted risk ratio , 1.30 ; 95 % CI , 1.07 - 1.57 ; P = 0.009 ) . Most of the excess events have not been associated previously with systemic therapy targeting vascular endothelial growth factor ( VEGF ) . CONCLUSIONS Ranibizumab and bevacizumab had similar effects on visual acuity over a 2-year period . Treatment as needed result ed in less gain in visual acuity , whether instituted at enrollment or after 1 year of monthly treatment . There were no differences between drugs in rates of death or arteriothrombotic events . The interpretation of the persistence of higher rates of serious adverse events with bevacizumab is uncertain because of the lack of specificity to conditions associated with inhibition of VEGF OBJECTIVE To develop and test the psychometric properties of a 25-item version of the National Eye Institute Visual Function Question naire ( NEI VFQ-25 ) . DESIGN Prospect i ve observational cohort study of persons with 1 of 5 chronic eye diseases or low vision who were scheduled for nonurgent visits in ophthalmology practice s and a reference sample of persons without eye disease . SETTING Eleven university-based ophthalmology practice s and the NEI Clinical Center . PATIENTS Eligible participants had to have 1 of the following eye conditions : age-related cataracts , age-related macular degeneration , diabetic retinopathy , primary open-angle glaucoma , cytomegalovirus retinitis , or low vision from any cause . Seven of the 12 sites also enrolled persons in a reference sample . Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error . All eligible persons had to be 21 years or older , English speaking , and cognitively able to give informed consent and participate in a health status interview . MEASUREMENTS AND MAIN RESULTS To provide the data needed to create the NEI VFQ-25  , all subjects completed an interview that included the 51-item NEI VFQ . Estimates of internal consistency indicate that the subscales of the NEI VFQ-25 are reliable . The validity of the NEI VFQ-25 is supported by high correlations between the short- and long-form versions of the measure , observed between-group differences in scores for persons with different eye diseases of varying severity , and the moderate-to-high correlations between the NEI VFQ-25 subscales that have the most to do with central vision and measured visual acuity . CONCLUSIONS The reliability and validity of the NEI VFQ-25 are comparable to those of the 51-item NEI VFQ field test version of the survey . This shorter version will be more feasible in setting s such as clinical trials where interview length is a critical consideration . In addition , preliminary analyses indicate that the psychometric properties of the NEI VFQ-25 are robust for the eye conditions studied ; this suggests that the measure will provide reproducible and valid data when used across multiple conditions of varying severity Objectives To evaluate the efficacy and safety of intravitreous bevacizumab injections for the treatment of neovascular age related macular degeneration . Design Prospect i ve , double masked , multicentre , r and omised controlled trial . Setting Three ophthalmology centres in the United Kingdom . Participants 131 patients ( mean age 81 ) with wet age related macular degeneration r and omised 1:1 to intervention or control . Interventions Intravitreous bevacizumab ( 1.25 mg , three loading injections at six week intervals followed by further treatment if required at six week intervals ) or st and ard treatment available at the start of the trial ( photodynamic treatment with verteporfin for predominantly classic type neovascular age related macular degeneration , or intravitreal pegaptanib or sham treatment for occult or minimally classic type neovascular age related macular degeneration ) . Main outcome measures Primary outcome : proportion of patients gaining ≥15 letters of visual acuity at one year ( 54 weeks ) . Secondary outcomes : proportion of patients with stable vision and mean change in visual acuity . Results Of the 131 patients enrolled in the trial , five patients did not complete the study because of adverse events , loss to follow-up , or death . In the bevacizumab group , 21 ( 32 % ) patients gained 15 or more letters from baseline visual acuity compared with two ( 3 % ) in the st and ard care group ( P<0.001 ) ; the estimated adjusted odds ratio was 18.1 ( 95 % confidence interval 3.6 to 91.2 ) and the number needed to treat was 4 ( 3 to 6 ) . In addition , the proportion of patients who lost fewer than 15 letters of visual acuity from baseline was significantly greater among those receiving bevacizumab treatment ( 91 % ( 59 ) v 67 % ( 44 ) in st and ard care group ; P<0.001 ) . Mean visual acuity increased by 7.0 letters in the bevacizumab group with a median of seven injections compared with a decrease of 9.4 letters in the st and ard care group ( P<0.001 ) , and the initial improvement at week 18 ( plus 6.6 letters ) was sustained to week 54 . Among 65 patients treated with bevacizumab  , there were no cases of endophthalmitis or serious uveitis related to the intervention . All end points with respect to visual acuity in the study eye at 54 weeks favoured bevacizumab treatment over st and ard care . Conclusions Bevacizumab 1.25 mg intavitreous injections given as part of a six weekly variable retreatment regimen is superior to st and ard care ( pegaptanib sodium , verteporfin , sham ) , with low rates of serious ocular adverse events . Treatment improved visual acuity on average at 54 weeks . Trial registration number Current controlled trials IS RCT Introduction Wet age-related macular degeneration ( AMD ) is a chronic eye condition that causes severe deterioration of vision and even blindness . Current wet AMD treatment in the UK involves the vascular endothelial growth factor inhibitors ranibizumab and aflibercept .  Patients with wet AMD require frequent and long-term monitoring for treatment to be effective , contributing to a substantial re source burden at wet AMD centers . The European license for ranibizumab was recently up date d with an individualized ‘ treat and extend ’ ( T&E ) regimen , comprising a structured monitoring and treatment protocol . This study evaluated the cost-effectiveness of ranibizumab T&E versus aflibercept within a UK setting . Methods An individual patient-level simulation model was developed utilizing treatment effects from a network meta- analysis of r and omized controlled trials . The model was conducted from a UK National Health Service ( NHS ) perspective over a lifetime horizon and the base case utilized probabilistic sensitivity analysis to assess uncertainty in the model . Additional scenario analyses were conducted to assess the impact of changes to the model inputs . Results Ranibizumab T&E was found to be more effective and less costly than aflibercept , providing , on average , an additional 1.058 quality -adjusted life years ( QALYs ) and a cost-saving of £ 19,604 over a lifetime horizon . At list price , ranibizumab T&E was found to be cost-effective versus aflibercept in 100 % of simulations at a willingness-to-pay threshold of £ 20,000 per QALY . The robustness of the results was tested in several scenario analyses ; ranibizumab T&E was found to be more effective , and less costly , than aflibercept in the vast majority of cases . Conclusion This evaluation suggests that treating patients with ranibizumab  according to the T&E regimen could be a better use of NHS re sources than aflibercept , and could , therefore , be considered as a first-line regimen for patients with wet AMD in the UK . Funding Novartis Pharmaceuticals UK Limited Background Age-related macular degeneration ( AMD ) is a blinding disease placing considerable burden on society due to blindness-associated costs . Intravitreal anti — vascular endothelial growth factors ( anti- 
    Output:
    
Comparing ranibizumab and aflibercept , either treatment can be more cost-effective depending on the assumptions used for drug prices and treatment frequencies .
As such , they may negatively influence overall patient outcomes and societal costs .