***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: This study compared four electronic head-mounted devices ( HMDs ) ( Jordy , Flipperport , Maxport and NuVision ) with conventional optical low-vision aids ( LVAs ) . The aim was to determine any performance differences for laboratory-based clinical measurements and practical visual tasks for patients with macular disease . Possible factors influencing success were explored . Ten patients with early onset macular disease ( EOMD ) and 10 with age-related macular disease ( AMD ) used the four HMDs , habitual spectacles and previously prescribed optical LVAs to complete a range of clinical measurements and everyday visual tasks . The clinical measurements were distance , intermediate and near acuities , and contrast sensitivity . The visual tasks were to read text of three sizes , to write a cheque and to identify grocery items on a shelf . Following the initial evaluation , each subject took home two r and omly selected HMD devices for 2 weeks , after which performance measures were repeated . No single HMD stood out as being superior overall . Flipperport and Jordy provided significantly better distance and intermediate acuity than the previously prescribed optical LVAs but near acuity and contrast sensitivity were not consistently better with any of the HMDs . Practice at home provided some improvement in performance with HMDs , nevertheless , optical aids remained the best devices for optimum functioning for the majority of tasks . Younger patients and those with better distance acuity were more likely to benefit from HMDs , particularly when reading small print . In low vision clinics , practitioners should continue to show patients conventional optical aids and demonstrate these electronic HMDs only when appropriate for the individual patient Background A subgroup of clinical trial subjects identified by baseline characteristics is a proper subgroup while a subgroup determined by post r and omization events or measures is an improper subgroup . Both types of subgroups are often analyzed in clinical trial papers . Yet , the extensive scrutiny of subgroup analyses has almost exclusively attended to the former . The analysis of improper subgroups thereby not only flourishes in numerous disguised ways but also does so without a corresponding awareness of its pitfalls . Comparisons of the grade of angina in a heart disease trial , for example , usually include only the survivors . This paper highlights some of the distinct ways in which outcome based subgroup analysis occurs , describes the hazards associated with it , and proposes a simple alternative approach to counter its analytic bias . Results Data from six published trials show that outcome based subgroup analysis , like proper subgroup analysis , may be performed in a post-hoc fashion , overdone , selectively reported , and over interpreted . Six hypothetical trial scenarios illustrate the forms of hidden bias related to it . That bias can , however , be addressed by assigning clinical ly appropriate scores to the usually excluded subjects and performing an analysis that includes all the r and omized subjects . Conclusion A greater level of awareness about the practice and pitfalls of outcome based subgroup analysis is needed . When required , such an analysis should maintain the integrity of r and omization . This issue needs greater practical and method ologic attention than has been accorded to it thus far OBJECTIVE To evaluate the effectiveness of a low-vision rehabilitation program . METHODS A multicenter r and omized clinical trial was conducted from November 2004 to November 2006 with a 4-month follow-up . A total of 126 patients were included , 98 % of whom were white and male . The patients were referred from eye or low-vision clinics and blind rehabilitation centers with a visual acuity in the better-seeing eye worse than 20/100 and better than 20/500 and were eligible for Veterans Affairs ( VA ) services .  Telephone interviews of patients were conducted in their homes before and after participation in an outpatient low-vision program at a VA medical care facility or a ( waiting list ) control group . The interviewer administering question naires by telephone was masked to patients ' assignments . Interventions included low-vision examination , counseling , and prescription and provision of low-vision devices and 6 weekly sessions provided by a low-vision therapist to teach use of assistive devices and adaptive strategies to perform daily living tasks independently . MAIN OUTCOME MEASURE Change in patients ' visual reading ability estimated from participant responses to the Veterans Affairs Low-Vision Visual Functioning Question naire ( LV VFQ-48 ) reading items completed at baseline compared with 4 months after enrollment for the treatment and control groups . The secondary outcomes were changes in other visual ability domains ( mobility , visual information processing , visual motor skills ) and overall visual ability from baseline to 4 months estimated from VA LV VFQ-48 difficulty ratings for subsets of items . RESULTS The treatment group demonstrated significant improvement in all aspects of visual function compared with the control group . The difference in mean changes was 2.43 logits ( 95 % confidence interval [ CI ] , 2.07 - 2.77 ; P < .001 ; effect size , 2.51 ) for visual reading ability ; 0.84 logit ( 95 % CI , 0.58 - 1.10 ; P < .001 ; effect size , 1.14 ) for mobility ; 1.38 logits ( 95 % CI , 1.15 - 1.62 ; P < .001 ; effect size , 2.03 ) for visual information processing ; 1.51 logits ( 95 % CI , 1.22 - 1.80 ; P < .001 ; effect size , 1.82 ) for visual motor skills ; and 1.63 logits ( 95 % CI , 1.40 - 1.86 ; P < .001 ; effect size , 2.51 ) for overall visual function . CONCLUSION The program effectively provided low-vision rehabilitation for patients with macular diseases . APPLICATIONS TO CLINICAL PRACTICE : At least 10 hours of low-vision therapy , including a home visit and assigned homework to encourage practice , is justified for patients with moderate and severe vision loss from macular diseases . Because the waiting-list control patients demonstrated a decline in functional ability , low-vision services should be offered as early as possible . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00223756 AIMS --A survey was undertaken to assess the effectiveness of an integrated approach to the provision of  low visual aids ( LVAs ) in south Devon over a 2 year follow up period . This integrated approach includes the assessment of patient needs by low vision therapists , followed by the provision of suitable LVAs , with particular emphasis on training in their use . METHODS --A total of 125 patients were selected at r and om from the 445 patients seen in the low vision clinic at Torbay Hospital in the year 1991 . These patients were sent question naires relating to the service over a 2 year period . Question naires from 111 patients were analysed at 1 year and 75 question naires together with 46 clinical re assessment s , after 2 years . RESULTS --Using a similar question naire to one used in a previous study in the UK from a unit where LVA training was not provided , not only was a higher rate of satisfaction found with the services provided , but also the LVAs dispensed were used more frequently . The majority of the LVAs provided were of the simple , inexpensive variety and wastage was very low . CONCLUSIONS --It was concluded that this integrated approach to low vision rehabilitation with emphasis on training in the use of less complex LVAs exceeds the performance of other types of service that rely on the dispensing of more complex LVAs Aim : To compare the effectiveness of three models of low vision rehabilitation for people with age related macular degeneration ( AMD ) referred for low vision rehabilitation ( LVR ) : ( a ) an enhanced low vision rehabilitation model ( ELVR ) including supplementary home based low vision rehabilitation ; ( b ) conventional low vision rehabilitation ( CLVR ) based in a hospital clinic ; ( c ) CLVR with home visits that did not include rehabilitation ( CELVR ) , intended to act as a control for the additional contact time with ELVR . Method : A single centre parallel group r and omised controlled trial in participants ’ homes and the low vision clinic , Manchester Royal Eye Hospital . People referred for LVR with a primary diagnosis of AMD and visual acuity worse than 6/18 in both eyes and equal to or better than 1/60 in the better eye . The main outcome measures were vision specific quality of life ( QoL ) ( primary outcome , VCM1 ) and generic health related QoL ( SF-36 ) ; psychological adjustment to vision loss ; measured task performance ; restriction in everyday activities ; use of low vision aids ( LVAs ) . Results : 226 participants were recruited ( median age 82 years ) ; 194 completed the trial ( 86 % ) . Except for SF-36 physical and mental component summary scores , arms did not differ significantly for any of the outcomes . Differences for the VCM1 were ELVR v CLVR , 0.06 ( 95 % CI to 0.17 to 0.30 , p = 0.60 ) ; ELVR v CELVR , 0.12 ( 95 % CI to 0.11 to 0.34 , p = 0.31 ) ; CELVR v CLVR , –0.05 ( 95 % CI –0.29 to 0.18 , p = 0.64 ) . Differences for the SF-36 favoured CLVR compared to ELVR ( ELVR v CLVR : physical = –6.05 , 95 % CI –10.2 to –1.91 , p = 0.004 ; mental = –4.04 , 95 % CI –7.44 to –0.65 , p = 0.02 ) . At 12 months , 94 % of participants reported using at least one LVA . Conclusion : ELVR was no more effective than CLVR . Research ers should be wary of proposing new LVR interventions without preliminary evidence of effectiveness , given the manifest lack of effectiveness of the model of enhanced LVR evaluated in the trial OBJECTIVE To determine the effectiveness of prism spectacles in people with age-related macular degeneration by relocating the retinal image . METHODS We implemented a r and omized , placebo-controlled , double-masked trial . Participants with age-related macular degeneration received a st and ard low-vision assessment and the prescription of conventional low-vision aids 6 weeks before the study intervention . Participants were r and omized to receive 1 of the following , including the optimal refractive correction : ( 1 ) custom , incorporating bilateral prisms to match participants ' preferred power and base direction ; ( 2 ) st and ard , incorporating st and ard bilateral prisms ( 6 prism diopters [ Delta ] base up for logMAR [ logarithm of the minimum angle of resolution ] visual acuity ( VA ) of 0.48 - 1.00 and 10Delta base up for logMAR VA of 1.02 - 1.68 ) ; or ( 3 ) placebo , consisting of spectacles matched in weight and thickness to prism spectacles but without prism . MAIN OUTCOME MEASURES Outcomes measured binocularly at baseline and 3-month follow-up included distance logMAR VA , reading speed , critical print size , visual functioning question naires , and observed visual task performance . Scores on the 25-item National Eye Institute Visual Functioning Question naire and the Melbourne Low-Vision ADL ( Activities of Daily Living ) Index were converted to linear estimates using Rasch analysis . The Manchester Low Vision Question naire was used to collect descriptive data . RESULTS A total of 225 participants completed the trial ( median age , 81 years ) . We found no significant effect of treatment group on any of the outcome measures , including VA , the primary outcome ( adjusted for baseline ) ( P = .63 ) . Participants ' responses to the Manchester Low Vision Question naire suggested that the prism spectacles added to their problems . CONCLUSIONS Prism spectacles are no more effective than conventional spectacles for people with age-related macular degeneration PURPOSE To evaluate and compare the functional and perceived benefits of wearing coloured lenses by patients with age-related macular degeneration ( ARMD ) . METHOD Ten subjects with early ARMD and five elderly controls wore a selection of NoIR wrap-around coloured lenses ( yellow 29.7 % light transmission , orange 22.9 % , red 16.8 % and grey 10.3 % ) , each for a duration of 7 days . Contrast sensitivity , colour vision , visual acuity , the effect of glare and peripheral sensitivity were measured for each lens and compared with a control ( no lens ) condition . Subjective ratings of visual performance were also scored . RESULTS Compared with the no filter condition , red and grey lenses reduced contrast sensitivity whereas yellow and orange lenses increased contrast sensitivity . These objective changes were supported by subjective ratings in subjects with ARMD . Grey lenses reduced the loss of contrast sensitivity usually suffered in the presence of glare , whereas visual acuity and peripheral sensitivity decreased with red lenses . Colour vision became distorted with red lenses in control subjects , but was relatively unaffected by the use of coloured lenses in subjects with ARMD . CONCLUSIONS The subjective benefit of coloured lenses appears to be due to a minor enhancement of contrast sensitivity OBJECTIVE The research ers sought to assess whether the widely used 1994 Cochrane Highly Sensitive Search Strategy ( HSSS ) for r and omized controlled trials ( RCTs ) in MEDLINE could be improved in terms of sensitivity , precision , or parsimony . METHODS A gold st and ard of 1,347 RCT records and a comparison group of 2,400 non-trials were r and omly selected from MEDLINE .  Terms occurring in at least 1 % of RCT records were identified . Fifty percent of the RCT and comparison group records were r and omly selected , and the ability of the terms to discriminate RCTs from non-trial records was determined using logistic regression . The best performing combinations of terms were tested on the remaining records and in MEDLINE . RESULTS The best discriminating term was " Clinical Trial " ( Publication Type ) . In years where the C 
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There was moderate-certainty evidence that reading duration was longer with the electronic devices and that they were easier to use .
Similar results were seen for electronic devices with the camera mounted in a ' mouse ' .
There is insufficient evidence supporting the use of a specific type of electronic or optical device for the most common profiles of low-vision aid users .
However , there is some evidence that st and -mounted electronic devices may improve reading speeds compared with optical devices .
There is less evidence to support the use of head-mounted or portable electronic devices ; however , the technology of electronic devices may have improved since the studies included in this review took place , and modern portable electronic devices have desirable properties such as flexible use of magnification .
There is no good evidence to support the use of filters or prism spectacles .