***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 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 Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more PURPOSE : To compare changes in reading performance parameters after implantation of 4 multifocal intraocular lens ( IOL ) models and a monofocal IOL . SETTING : Department of Ophthalmology , Paracelsus Medical University , Salzburg , Austria . DESIGN : Prospect i ve r and omized controlled clinical trial . METHODS : Patients with bilateral cataract without additional ocular pathology were scheduled for bilateral implantation of Acri . Smart 48S monofocal , Acrysof Restor SN6AD3 apodized multifocal , AT LISA 366D diffractive multifocal , Tecnis ZMA00 diffractive multifocal , or Rezoom refractive multifocal IOLs .  Bilateral corrected and uncorrected reading acuity , reading distance , mean and maximum reading speeds , and smallest log‐scaled print size of a Radner reading chart were evaluated under bright lighting conditions ( 500 lux ) using the Salzburg Reading Desk . Pupil size was not measured throughout the trial . The minimum follow‐up was 12 months . RESULTS : The diffractive multifocal groups had significantly better uncorrected reading acuity and uncorrected smallest print size than the monofocal and refractive multifocal groups 1 , 6 , and 12 months postoperatively . The diffractive IOL groups had comparable uncorrected reading distance of approximately 32 cm , which was larger in the monofocal group ( 38.9 ± 8.4 cm ) and refractive multifocal group ( 37.1 ± 7.3 cm ) at the last visit . Patients with  diffractive IOLs  could read print sizes of approximately 0.74 to 0.87 mm , which was much better than in the monofocal and refractive multifocal groups . The diffractive AT LISA IOL provided the best reading speed values ( mean and maximum , corrected and uncorrected ) . CONCLUSION : Multifocal IOLs with a diffractive component provided good reading performance that was significantly better than that obtained with a refractive multifocal or monofocal IOL . Financial Disclosure : Drs . Grabner and Dexl were patent owners of the Salzburg Reading Desk technology ( now owned by SRD‐Vision , LLC ) . No other author has a financial or proprietary interest in any material or method mentioned PURPOSE To compare new-generation multifocal intraocular lenses ( IOLs ) with monofocal IOLs . DESIGN R and omized prospect i ve clinical trial . PARTICIPANTS Sixty-two consecutive patients with cataract , seen between January of 2005 and January of 2006 at the Department of Ophthalmology of Palermo University Hospital in Italy , were bilaterally implanted with monofocal ( AR 40 , Advanced Medical Optics [ AMO ] , Santa Ana , CA ; 15 patients ) , multifocal refractive ( Array SA40N , AMO ; 16 patients ) , multifocal refractive ( ReZoom , AMO ; 15 patients ) , or multifocal diffractive pupil-independent ( Tecnis ZM900 , AMO ; 16 patients ) IOLs . INTERVENTION Bimanual phacoemulsification . MAIN OUTCOME MEASURES Primary outcomes were far , near , and intermediate visual acuity of the 4 IOL-implanted groups . Secondary outcomes were defocusing curves , contrast sensitivity , patients ' quality of life ( 7-item visual function question naire [ VF-7 ] , halos and glare presence , overall satisfaction ) , and spectacle independence . Snellen visual acuity was measured as uncorrected visual acuity ( UCVA ) , best corrected visual acuity ( BCVA ) , uncorrected near visual acuity ( UCNVA ) , best distance corrected near visual acuity ( BDCNVA ) , best corrected near visual acuity ( BCNVA ) , uncorrected intermediate visual acuity ( UCIVA ) , and best distance corrected intermediate visual acuity ( BDCIVA ) . RESULTS UCNVA was 20/50 in the monofocal IOL group , compared with 20/32 or better in the multifocal IOL groups ( P<0.0005 ) . The monofocal IOL group exhibited a lower BDCNVA than the multifocal IOL groups ( P<0.0005 ) . The diffractive multifocal IOL group performed better than either refractive group ( P = 0.007 ) . UCIVA was significantly different ( P = 0.001 ) among the groups : monofocal ( AR 40 ) 20/32 ; multifocal refractive ( Array SA40N ) 20/30 ; multifocal refractive ( ReZoom ) 20/25 ; and multifocal diffractive ( Tecnis ZM900 ) 20/30 . Defocusing curves with -3.00 diopter lens exhibited a better trend in the diffractive group . The refractive multifocal IOL groups exhibited lower contrast sensitivities at 3 cycles/degree ( P = 0.038 ) . The VF-7 mean score was significantly lower in the monofocal than the multifocal IOL groups ( P = 0.002 ) . Night halos were more common in the refractive groups ( P<0.01 ) . Spectacle independence was 20 % in the monofocal IOL group , 43.7 % and 53.3 % in the refractive multifocal IOL groups , and 87.5 % in the diffractive multifocal IOL group ( P<0.05 ) . CONCLUSIONS Multifocal IOLs provide a greater depth of focus and higher patient satisfaction , and make intermediate and near visual tasks easier than do monofocal lenses . New-generation , diffractive , pupil-independent multifocal IOLs provide better near vision , equivalent intermediate vision , less unwanted photic phenomena , and greater spectacle independence than either monofocal or refractive multifocal IOLs OBJECTIVE To compare the binocular near vision performance in patients implanted with the 1CU accommodating intraocular lens ( IOL ) with a multifocal and monofocal IOL .  DESIGN Prospect i ve , r and omized , double-masked clinical trial . PARTICIPANTS Ninety patients presenting for cataract surgery to the Department of Ophthalmology , Hillingdon Hospital were r and omized to receive the 1CU accommodative IOL , a multifocal IOL , or a monofocal IOL ( control group ) . METHODS Patients underwent bilateral sequential phacoemulsification with implantation of 1 of the 3 IOL types and were assessed at 3 and 18 months after second-eye surgery . MAIN OUTCOME MEASURES Logarithm of the minimum angle of resolution distance and near visual acuities ( VAs ) ( unaided and distance corrected ) , contrast sensitivity , and accommodative 
    Output:
    
There was no difference in pooled estimates of corrected or uncorrected distance vision  between multifocal and st and ard IOLs .
Newer multifocal lenses had statistically significantly better outcomes than older diffractive lenses or refractive lenses , when compared to monofocal IOLs , in near vision , quality of vision , and risk of halos .
Conclusions Multifocal IOLs compared to st and ard IOLs or monovision result in better uncorrected near vision and a higher proportion of patients who achieve spectacle independence , but greater risk of unwanted visual phenomena .
Newer diffractive lenses may be better than refractive lenses in near vision and quality of vision outcomes , with less risk of halos than older diffractive lenses and refractive lenses . (