***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 describe fluorescein angiographic guidelines for the use of verteporfin therapy in patients with subfoveal choroidal neovascularization ( CNV ) secondary to age-related macular degeneration ( AMD ) or other conditions based on 2-year vision outcomes from the Treatment of Age-Related Macular Degeneration With Photodynamic Therapy ( TAP ) Investigation and Verteporfin in Photodynamic Therapy ( VIP ) Trial . METHODS Three multicenter , double-masked , placebo-controlled r and omized clinical trials at 28 ophthalmology clinical centers in Europe and North America involving prospect ively identified patients with best-corrected visual acuity ( Snellen equivalent ) of approximately 20/20 to 20/200 , subfoveal CNV secondary to AMD or pathologic myopia with evidence of CNV , and a lesion greatest linear dimension of 5400 micro m or less .  Fluorescein angiography was to be performed on all patients at enrollment and at regular 3-month follow-up visits through 2 years . The initial treatment laser spot size and all subsequent treatment decisions were based on the investigator 's interpretation of these fluorescein angiograms . Photographic material s forwarded to the Wilmer Photograph Reading Center were review ed by masked grade rs . MAIN OUTCOME MEASURES Baseline angiographic features , including lesion composition and size , morphologic response to treatment during follow-up ( eg , absence of leakage ) , and reliability ( kappa values ) of grading selected characteristics based on a 10 % regrading of baseline visits . RESULTS Terms and examples of different lesions and lesion components are provided to assist recognition of fluorescein angiographic characteristics of choroidal neovascular lesions that were important in determining when and where to apply verteporfin therapy . The kappa statistics for agreement of identification of lesion characteristics by the Wilmer Photograph Reading Center for these trials ranged from 0.70 to 0.85 . CONCLUSIONS Ophthalmologists should consider interpreting fluorescein angiographic images of subfoveal lesions with terms provided to follow recommendations regarding which patients are most likely to benefit from verteporfin therapy based on results from the TAP Investigation and VIP Trial PURPOSE To determine if photodynamic therapy with verteporfin ( Visudyne ; Novartis AG , Bülach , Switzerl and ) , termed verteporfin therapy , can safely reduce the risk of vision loss compared with a placebo ( with sham treatment ) in patients with subfoveal choroidal neovascularization caused by age-related macular degeneration who were identified with a lesion composed of occult with no classic choroidal neovascularization , or with presumed early onset classic choroidal neovascularization with good visual acuity letter score . METHODS This was a double-masked , placebo-controlled ( sham treatment ) , r and omized , multicenter clinical trial involving 28 ophthalmology practice s in Europe and North America . The study population was patients with age-related macular degeneration , with subfoveal choroidal neovascularization lesions measuring no greater than 5400 microm in greatest linear dimension with either 1 ) occult with no classic choroidal neovascularization , best-corrected visual acuity score of at least 50 ( Snellen equivalent approximately 20/100 ) , and evidence of hemorrhage or recent disease progression ; or 2 ) evidence of classic choroidal neovascularization with a best-corrected visual acuity score of at least 70 ( better than a Snellen equivalent of approximately 20/40 ) ; assigned r and omly ( 2:1 ) to verteporfin therapy or placebo therapy . Verteporfin ( 6 mg per square meter of body surface area ) or placebo ( 5 % dextrose in water ) was administered by means of intravenous infusion of 30 ml over 10 minutes . Fifteen minutes after the start of the infusion , a laser light at 689 nm delivered 50 J/cm(2 ) by application of an intensity of 600 mW/cm(2 ) over 83 seconds using a spot size with a diameter 1000 microm larger than the greatest linear dimension of the choroidal neovascularization lesion on the retina . At follow-up examinations every 3 months , retreatment with the same regimen was applied if angiography showed fluorescein leakage . The main outcome measure was at least moderate vision loss , that is , a loss of at least 15 letters ( approximately 3 lines ) , adhering to an intent-to-treat analysis with the last observation carried forward to impute for missing data . RESULTS Two hundred ten ( 93 % ) and 193 ( 86 % ) of the 225 patients in the verteporfin group compared with 104 ( 91 % ) and 99 ( 87 % ) of the 114 patients in the placebo group completed the month 12 and 24 examinations , respectively . On average , verteporfin-treated patients received five treatments over the 24 months of follow-up . The primary outcome was similar for the verteporfin-treated and the placebo-treated eyes through the month 12 examination , although a number of secondary visual and angiographic outcomes significantly favored the verteporfin-treated group . Between the month 12 and 24 examinations , the treatment benefit grew so that by the month 24 examination , the verteporfin-treated eyes were less likely to have moderate or severe vision loss . Of the 225 verteporfin-treated patients , 121 ( 54 % ) compared with 76 ( 67 % ) of 114 placebo-treated patients lost at least 15 letters ( P = .023 ) . Likewise , 67 of the verteporfin-treated patients ( 30 % ) compared with 54 of the placebo-treated patients ( 47 % ) lost at least 30 letters ( P = .001 ) . Statistically significant results favoring verteporfin therapy at the month 24 examination were consistent between the total population and the subgroup of patients with a baseline lesion composition identified as occult choroidal neovascularization with no classic choroidal neovascularization . This subgroup included 166 of the 225 verteporfin-treated patients ( 74 % ) and 92 of the 114 placebo-treated patients ( 81 % ) . In these patients , 91 of the verteporfin-treated group ( 55 % ) compared with 63 of the placebo-treated group ( 68 % ) lost at least 15 letters ( P = .032 ) , whereas 48 of the verteporfin-treated group ( 29 % ) and 43 of the placebo-treated group ( 47 % ) lost at least 30 letters ( P = .004 ) . Other secondary outcomes , including visual acuity letter score worse than 34 ( approximate Snellen equivalent of 20/200 or worse ) , mean change in visual acuity letter score , development of classic choroidal neovascularization , progression of classic choroidal neovascularization and size of lesion , favored the verteporfin-treated group at both the month 12 and month 24 examination for both the entire study group and the subgroup of cases with occult with no classic choroidal neovascularization at baseline . Subgroup analyses of lesions composed of occult with no classic choroidal neovascularization at baseline suggested that the treatment benefit was greater for patients with either smaller lesions ( 4 disc areas or less ) or lower levels of visual acuity ( letter score less than 65 , an approximate Snellen equivalent of 20/50(-1 ) or worse ) at baseline . Prospect ively planned multivariable analyses confirmed that these two baseline variables affected the magnitude of treatment benefit . ( ABSTRACT TRUNCATED Aims : ( 1 ) A prospect i ve study to assess visual function measures and quality of life ( QoL ) in patients with wet age related macular degeneration ( AMD ) treated with photodynamic therapy ( PDT ) .  ( 2 ) To assess if PDT prevents severe visual loss ( loss of six or more lines of distance visual acuity ) in the treated eye . Methods : 48 of 51 recruited patients with predominantly classic subfoveal choroidal neovascularisation ( CNV ) secondary AMD who were treated with PDT  were followed up for 1 year . Assessment included distance and near visual acuity , contrast sensitivity , vision related quality of life and fluorescein angiography .  Photodynamic therapy using Visudyne was carried out according to st and ard protocol . Patients were followed up every 3 months and treatment repeated if there was significant leakage from CNV . Results : At the 12 month follow up , 71 % ( n = 34 ) of the patients lost less than three lines of best corrected distance visual acuity . Although there were significant decreases in some of the QoL items tested , patients were significantly less anxious and more independent outdoors at the 12 month follow up . Conclusion : This study is in keeping with published literature with PDT preventing severe visual loss in two thirds of treated patients with predominantly classic CNV Purpose : To provide broad clinical experience and to gather safety data on photodynamic therapy with verteporfin ( Visudyne , Novartis AG , Basel , Switzerl and ) , also termed verteporfin therapy , in patients with predominantly classic subfoveal choroidal neovascularization ( CNV ) secondary to age-related macular degeneration ( AMD ) . The Verteporfin in Age-related Macular Degeneration ( VAM ) Study was design ed to provide exp and ed access to verteporfin therapy after beneficial results for these cases were reported but before regulatory approval in North America . Methods : This open-label multicenter study from September 1999 through June 2000 enrolled among 222 centers patients 50 years or older in the United States , or 40 years or older in Canada , with age-related macular degeneration and subfoveal CNV with a lesion composition that was predominantly classic CNV on fluorescein angiography . Corrected visual acuity with habitual eyewear in the office setting was 20/40 to 20/200 , inclusive . All patients received verteporfin therapy and returned for follow-up every 3 months . At those follow-up examinations , additional courses of treatment were recommended if any fluorescein leakage from CNV was identified . Safety information was collected from patient self-reporting , question ing ( in person and by telephone ) , and physician evaluation . Safety was assessed by evaluating the effect of treatment on corrected distance visual acuity and by evaluating adverse events . Results : A total of 4,435 patients were enrolled of whom 4,051 ( 91 % ) completed the study after receiving 6,701 treatments . Most patients received only one treatment in VAM before regulatory approval of verteporfin in the United States and Canada . Three hundred patients ( 6.8 % ) experienced an adverse event considered by the treating ophthalmologist to be associated with treatment , including 115 ( 2.6 % ) with abnormal or decreased vision , of whom 25 ( 0.6 % ) experienced acute severe visual acuity decrease , and 14 ( 0.3 % ) with transient infusion-related back pain . Patients were advised to avoid exposure to direct sunlight for 24 hours ; however , after verteporfin administration only 2 ( 0.05 % ) reported a photosensitivity reaction . An additional course of verteporfin therapy was administered to 1,739 of 2,314 patients ( 75.2 % ) who had a month 3 examination that was not their close-out visit and 177 of 266 ( 66.5 % ) who had a month 6 examination that was not their close-out visit . Conclusions : Verteporfin therapy exhibited no additional or new safety concerns . The therapy associated with a low incidence of adverse events when exp and ed access was provided in a large , open-label , multicenter study , including a low incidence ( 0.05 % ) of reported photosensitivity reactions despite a short photosensitivity protection period ( 24 hours ) following verteporfin administration PURPOSE To evaluate vascular changes documented by confocal indocyanine green angiography ( ICGA ) through 2 years after photodynamic therapy ( PDT ) with verteporfin of neovascular age-related macular degeneration ( AMD ) . DESIGN Single-center , 2-year , r and omized , double-masked , interventional , placebo-controlled trial ( subset from Treatment of AMD with PDT Study [ TAP ] ) . PARTICIPANTS Sixty patients with subfoveal choroidal neovascularization ( CNV ) result ing from AMD . INTERVENTION Patients were r and omized in a ratio of 2:1 to a st and ard regimen using verteporfin therapy at a drug dose of 6 mg/m(2 ) body surface area and a light dose of 50 J/cm(2 ) or a sham treatment with placebo infusion and light exposure . Retreatments , if persistent fluorescein leakage from CNV was documented , were scheduled at 3-month intervals for up to 2 years . Confocal ICGA with tomographic sections was performed at baseline and continuously at the month 3 , 6 , 12 , and 24 examinations using a st and ardized protocol . MAIN OUTCOME MEASURES Analysis included the size of the neovascular net , the area of late hyperfluorescence , and choroidal hypofluorescence during early- and late-phase imaging . RESULTS In the verteporfin-treated group , the mean size of the CNV and the mean area of late leakage consistent with active leakage or staining showed no further enlargement at month 12 and were reduced at month 24 . In the 
    Output:
    
Photodynamic therapy in people with choroidal neovascularisation due to AMD is probably effective in preventing visual loss though there is doubt about the size of the effect .