***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 Two million cataract extraction s are performed annually in the United States . The procedure is nearly always accompanied by implantation of a monofocal intraocular lens ( IOL ) , which corrects the patient 's distance vision . The authors ' objective was to measure visual function and quality -of-life outcomes associated with bilateral implantation of a multifocal IOL , which corrects distance and near vision , and to compare the outcomes with those of the st and ard therapy . DESIGN A prospect i ve , r and omized , double-masked , clinical trial was conducted at eight sites in the United States , seven sites in Germany , and one site in Austria . PARTICIPANTS Participants included 245 cataract patients , 127 of whom received the multifocal IOL bilaterally and 118 of whom received a monofocal IOL of nearly identical construction bilaterally . METHODS Clinical data included visual acuity ( VA ) , complications , and adverse events . Quality -of-life data were collected using a previously vali date d survey instrument at baseline , after first eye surgery , and after second eye surgery . RESULTS At 3 months after surgery , patients who had received multifocal IOLs had significantly better uncorrected and distance corrected binocular near VA compared with patients who had received monofocal IOLs ( mean uncorrected VA , 20/26 multifocal vs. 20/40 monofocal ; mean distance corrected VA , 20/28 multifocal vs. 20/45 monofocal ; P < 0.0001 ) . Additionally , 96 % of patients who had received multifocal IOLs and 65 % of patients who had received monofocal IOLs achieved both 20/40 and J3 ( Jaeger ) or better uncorrected , binocular distance and near visual acuities ( P < 0 . 0001 ) . Patients who had received multifocal IOLs were more likely than patients who had received monofocal IOLs to never wear glasses overall ( 32 % multifocal vs. 8 % monofocal ; P < 0.0001 ) . On a 4-point scale , patients who had received multifocal IOLs on average reported having between " a little bit " and " some " glare or halo , whereas patients who had received monofocal IOLs reported between " none " and " a little bit " of glare or halo ( 1.57 vs. 0.43 ; P < 0.001 ) . Patients who had received multifocal IOLs rated their vision without glasses better overall at near and at intermediate distances ( P < or = 0.002 ) and demonstrated better visual function for near tasks and social activities . CONCLUSIONS Cataract patients who received multifocal IOLs at time of surgery obtained better uncorrected and distance corrected near VA and reported better overall vision , less limitation in visual function , less spectacle dependency , and more glare or halo than those who received traditional monofocal IOLs Aims To evaluate the functional effect of bilateral implantation of two different multifocal intraocular lenses ( IOL ) compared with the st and ard monofocal IOL . Methods Sixty-nine patients were recruited into a prospect i ve , double-masked , r and omised , controlled trial at a single hospital in the United Kingdom . Sixty completed follow-up ; 16 implanted with  monofocal IOLs  , 29 with AMO ’ ARRAY ’ multifocal IOLs and 15 with Storz ’ TRUEVISTA ’ bifocal IOLs . Phacoemulsification and IOL implantation was performed to a st and ardised technique in both eyes within a 2-month period . The main outcome measures were distance and near visual acuity , depth of field and vali date d assessment of subjective function ( TyPE question naire ) . Results Unaided distance acuity was good , and equivalent across the three groups . Corrected distance acuity was significantly lower in the bifocal group . Patients with multifocal and bifocal IOLs could read smaller absolute print size than those in the monofocal group ( P = 0.05 ) , but at a closer reading distance such that mean unaided near acuity was equal in the three groups . Corrected near acuity was significantly higher in the monofocal control group ( P < 0.05 ) . Depth of field was increased in multifocal ( P = 0.06 ) and bifocal ( P = 0.004 ) groups . Overall visual satisfaction was equal in the three groups , while near visual satisfaction was higher in the multifocal group than the monofocal ( P = 0.04 ) . Spectacle independence was not seen in the monofocal group , but was achieved in 28 % of multifocal IOL patients and 33 % of bifocal patients ( P < 0.001 ) . Adverse symptoms such as glare and haloes were significantly more bothersome with multifocal ( not bifocal ) IOLs than monofocals ( P = 0.01 ) . Conclusions Multifocal and bifocal IOLs  improved unaided near vision performance , with around one in three patients becoming spectacle-independent . The main adverse effect was an increased incidence of subjective glare and haloes in the multifocal IOL group Objective To examine the prevalence of outcome reporting bias — the selection for publication of a subset of the original recorded outcome variables on the basis of the results — and its impact on Cochrane review s. Design A nine point classification system for missing outcome data in r and omised trials was developed and applied to the trials assessed in a large , unselected cohort of Cochrane systematic review s. Research ers who conducted the trials were contacted and the reason sought for the non-reporting of data . A sensitivity analysis was undertaken to assess the impact of outcome reporting bias on review s that included a single meta- analysis of the review primary outcome . Results More than half ( 157/283 ( 55 % ) ) the review s did not include full data for the review primary outcome of interest from all eligible trials . The median amount of review outcome data missing for any reason was 10 % , whereas 50 % or more of the potential data were missing in 70 ( 25 % ) review s. It was clear from the publications for 155 ( 6 % ) of the 2486 assessable trials that the research ers had measured and analysed the review primary outcome but did not report or only partially reported the results . For reports that did not mention the review primary outcome , our classification regarding the presence of outcome reporting bias was shown to have a sensitivity of 88 % ( 95 % CI 65 % to 100 % ) and specificity of 80 % ( 95 % CI 69 % to 90 % ) on the basis of responses from 62 trialists . A third of Cochrane review s ( 96/283 ( 34 % ) ) contained at least one trial with high suspicion of outcome reporting bias for the review primary outcome . In a sensitivity analysis undertaken for 81 review s with a single meta- analysis of the primary outcome of interest , the treatment effect estimate was reduced by 20 % or more in 19 ( 23 % ) . Of the 42 meta-analyses with a statistically significant result only , eight ( 19 % ) became non-significant after adjustment for outcome reporting bias and 11 ( 26 % ) would have overestimated the treatment effect by 20 % or more . Conclusions Outcome reporting bias is an under-recognised problem that affects the conclusions in a substantial proportion of Cochrane review s. Individuals conducting systematic review s need to address explicitly the issue of missing outcome data for their review to be considered a reliable source of evidence . Extra care is required during data extraction , review ers should identify when a trial reports that an outcome was measured but no results were reported or events observed , and contact with trialists should be encouraged PURPOSE Evaluate the visual performance of the AcrySof ReSTOR intraocular lens ( IOL ) and compare it with the monofocal SA60AT IOL . DESIGN Prospect i ve , nonr and omized , clinical trial . METHODS Forty patients ( 80 eyes ) from the Federal University of São Paulo were enrolled in two groups . Twenty-five patients were assigned to the  ReSTOR  group and 15 patients to the monofocal group . Inclusion criteria were corneal astigmatism < 1.0 diopter , potential acuity meter > 0.2 logMAR units , and no associated ocular diseases . Parameters analyzed included distance uncorrected and best-corrected visual acuity , near uncorrected and distance corrected visual acuity , intermediate visual acuity , contrast sensitivity ( Pelli-Robson chart ) , stereopsis ( Titmus test ) , reading speed , wavefront measurement ( LADARWave aberrometer ) , and a quality -of-life question naire . main outcome measure : Distance and near uncorrected and best distance corrected visual acuity , contrast sensitivity , and reading speed . RESULTS Distance uncorrected and best-corrected visual acuity in the ReSTOR group were not statistically different from the monofocal group ( P = .66 ) . Near uncorrected and distance corrected visual acuity were statistically better in the ReSTOR group than the monofocal group ( 0.16 + /- 0.13 vs 0.62 + /- 0.09 , P < .001 , and 0.14 + /- 0.12 vs 0.62 + /- 0.07 , P < .001 , respectively ) . The ReSTOR group demonstrated less spherical aberrations compared with the monofocal group ( P < .001 ) . Monocular photopic contrast sensitivity was statistically lower in the ReSTOR group ( P < .001 ) . Stereopsis and reading speed were not statistically different between the groups . CONCLUSION The AcrySof ReSTOR IOL provides a satisfactory full range of vision and achieves a more satisfactory quality of life when compared with the monofocal SA60AT IOL , but with lower contrast sensitivity Purpose : To compare contrast sensitivity ( CS ) after implantation of a diffractive bifocal intraocular lens ( IOL ) and a monofocal IOL of similar design . Setting : Seven European centers . Methods : In this r and omized , prospect i ve study , CS was tested 5 months after  cataract and IOL implantation surgery  in 115 patients with a diffractive bifocal IOL and 106 patients with a monofocal IOL .  It was also tested in a subgroup of 38 patients who had bilateral implantation of a diffractive bifocal IOL .  Contrast sensitivity was tested using the Vision Contrast Test System ( VCTS ) . Results : In patients with a best corrected visual acuity ( BCVA ) of 1.0 or better , the CS at all spatial frequencies ( 1.5 to 18 cycles/degree ) , both at distance and near , was slightly lower in the bifocal IOL group than in the monofocal group . Mean values were within the normal range . In patients with a BCVA of less than 1.0 , the CS was lower and the difference between the bifocal and monofocal groups was less . In patients with bilateral bifocal IOLs  , CS was better when tested bilaterally than when testing the better eye alone . Pupil size affected the results to a small degree . Contrast sensitivity appeared to improve over time after implantation of a diffractive bifocal IOL . Conclusions : In patients with cataract and no other eye pathology , the diffractive bifocal IOL will slightly reduce the CS at all spatial frequencies . In those with reduced visual acuity after cataract surgery , CS will be reduced accordingly . In this situation , the reduction from the diffractive bifocal optic would be minor Purpose To compare disk halo size in response to a glare source in eyes with an aspheric apodized diffractive multifocal intraocular lens ( IOL ) or aspheric monofocal IOL .  Setting Rementeria Ophthalmological Clinic , Madrid , Spain . Design Prospect i ve r and omized masked study . Method Halo radius was measured using a vision monitor ( MonCv3 ) with low‐luminance optotypes in eyes that had cataract surgery and bilateral implantion of an Acrysof Restor SN6AD1 multifocal IOL or Acrysof IQ monofocal IOL 6 to 9 months previously . The visual angle subtended by the disk halo radius was calculated in minutes of arc ( arcmin ) . Patient complaints of halo disturbances were recorded . Monocular uncorrected distance visual acutity ( UDVA ) and corrected distance visual acuity ( CDVA ) were measured using high‐contrast ( 96 % ) and low‐contrast ( 10 % ) logMAR letter charts . Results The study comprised 39 eyes of 39 subjects ( aged 70 to 80 years ) ; 21 eyes had a multifocal IOL and 18 eyes a monofocal IOL .  The mean halo radius was 35 arcmin larger in the multifocal IOL group than the monofocal group ( P < .05 ) . Greater halo effects were reported in the multifocal IOL group ( P < .05 ) . The mean monocular high‐contrast UDVA and low‐contrast UDVA did not vary significantly between groups , whereas the mean monocular high‐contrast CDVA and low‐contrast CDVA were significantly worse at 0.12 logMAR and 0.13 logMAR in the multifocal than in the monofocal IOL group , respectively ( P < .01 ) . A significant positive correlation was detected by multiple linear regression between the halo radius and low‐contrast UDVA in the multifocal IOL group ( r = 0.72 , P < .001 ) . Conclusions The diffractive multifocal IOL gave rise to a larger disk halo size , which was correlated with a worse low‐contrast UDVA . Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned PURPOSE : To evaluate and compare patient‐reported visual function , spectacle independence , and quality of life before and after cataract surgery with bilateral diffractive multifocal or monofocal intraocular lens ( IOL ) implantation .  SET 
    Output:
    
Multifocal IOLs are effective at improving near vision relative to monofocal IOLs although there is uncertainty as to the size of the effect .
Motivation to achieve spectacle independence is likely to be the deciding factor