the feasibility and effectiveness of vision screening programs for detection of glaucoma , diabetic retinopathy ( dr ) , cataracts , age - related macular degeneration ( amd ) have been described [ 13 ] . the majority of such programs employ digital color fundus imaging to determine whether a follow - up examination with an ophthalmologist or optometrist is required . several investigators initiated studies examining the use of additional technologies and imaging modalities , including software - assisted digital filters , retinal thickness analyzer , and slit lamp microscopy to enhance the quality of obtained images aimed at improving detection and characterization of vision - threatening diseases ( vtds ) [ 46 ] . in addition , using a structured questionnaire to assess patient satisfaction attending a teleophthalmology versus conventional ( i.e. , in - person ) screening for dr , kumari rani et al . found that 34% of participants preferred teleophthalmology to conventional screening and 61% felt that both types of screenings were equally satisfying . in this and other studies , the most common reasons given for improved patient satisfaction with teleophthalmology versus conventional screenings were cost reduction , ability to view images directly , decreased travel time , and direct consultation with a clinician [ 7 , 8 ] . fundus autofluorescence ( faf ) is a specific wavelength light emission from lipofuscin and other molecules that accumulate in retinal pigment epithelial ( rpe ) cells secondary to photoreceptor oxidative damage . specific faf patterns have been described for numerous ocular diseases and conditions , and they may also be useful in monitoring disease progression . in the current study , we describe and analyze the incorporation of faf technology in our community - based ocular screening program . screening participants included homeless and working - poor individuals at soup kitchens and churches in essex county , new jersey . fifty consecutive individuals were enrolled in this prospective , pilot imaging study in march 2011 . a detailed description of our screening program has been published previously . in brief , the screening team consisted of : ( 1 ) senior medical students who completed an intake form ( personal and family history of medical and ocular problems , smoking history , etc . ) , measured blood pressure , pulse , and oxygen saturation , assessed visual acuity ( va ; simav , padova , italy ) and visual fields ( frequency doubling technology ; carl zeiss meditec , inc . , dublin , ca ) ; ( 2 ) an imaging technician who measured intraocular pressure ( iop ; canon tx - f full auto non - contact tonometer , tokyo , japan ) , performed nonmydriatic color and faf imaging ( canon cx-1 15.1 megapixel camera with cmos sensor , tokyo , japan ) ; and ( 3 ) an onsite medical director who analyzed complete screening data , reviewed color and faf images , and made referrals for follow - up examination as needed . those participants requiring additional follow - up examinations were referred to the eye clinic at the institute of ophthalmology and visual science at university of medicine and dentistry of new jersey ( newark , nj ) that accepts uninsured patients . presenting va was defined as the subject 's entering vision with distance correction ( i.e. , contacts or glasses ) , if applicable . snellen va was converted into log mar scale , averaged , and then reconverted back into snellen va . by starting the screening process in a staggered fashion ( i.e. , at different stations ) , on average , 11 subjects were screened per hour ( not including the time required for reviewing screening data and counseling the participants ) . based on personal , social , and/or family history , information packets ( available in english or spanish ) were handed out and participants were counseled accordingly . nonmydriatic color and faf images were saved and viewed on a high - resolution , wide - screen fujitsu laptop ( kanagawa , japan ) using digital imaging and communications in medicine ( dicom)-compatible canon eye - q software ( canon medical systems , irvine , ca ) . these were evaluated side - by - side for potential changes in the optic nerve head ( i.e. , cup - to - disc ratio , asymmetry , neuro - retinal rim color , and nerve fiber layer integrity ) , blood vessels ( i.e. , artery - to - vein ratio and nicking , microaneurysm formation , and neovascularization ) , and macula and posterior pole ( i.e. , pigmentary changes and drusen formation ) . following nonmydriatic color imaging , a second set of nonmydriatic images was taken in the faf mode ( 530/640  nm exciter / barrier filters ) . subjects were allowed to dark - adapt for 2 - 3 minutes . in order to prevent accommodation and pupillary constriction , a single photograph was captured per eye at a 300 watts / second flash intensity . two to three minutes were required in between in order for the eyes to recover . the resulting 256 monochromatic , grayscale images were then analyzed side - by - side with color images . ( i.e. , amd , drusen ) , the emphasis was placed on the macular region , which was assessed for changes in fluorescence . hypofluorescence signified rpe cell death , while hyperfluorescence suggested active expansion of area of geographic atrophy ( ga ) . hyperfluorescence can be classified according to specific phenotypic patterns that can be associated with amd progression . for glaucoma , the peripapillary region was of particular interest as hyperfluorescence in this area has been shown to correlate with optic nerve atrophy and/or glaucoma progression . this is different from a myopic crescent , which would appear as a gray band typically spanning the temporal peripapillary region . as for dr , we focused on diabetic macular edema ( dme ) that may appear as areas of hyperfluorescence . females represented 52% ( n = 26 ) . there were 29 ( 58% ) african americans , seven ( 14% ) caucasians , seven ( 14% ) hispanics , and seven ( 14% ) others . nine ( 18% ) subjects had diabetes mellitus type 2 for a mean duration of 10.5 years ; 13 ( 26% ) had hypertension ( based on self - reported history and/or blood pressure measurements at the screening ) ; and 16 ( 32% ) were active smokers . only 14 ( 28% ) had a dilated fundus examination within the past year . mean  sd iop was 14.8  3.9  mm  hg and 14.9  4.4  mm  hg in the right and left eye , respectively . performing color and faf imaging on each eye resulted in reviewing 44 images per hour . we identified nine ( 18% ) individuals with distinct color and/or faf patterns representing dr ( n = 3 ) , focal rpe defects ( n = 2 ) , dme ( n = 1 ) , amd ( n = 1 ) , central serous retinopathy ( csr ; n = 1 ) , and ocular trauma ( n = 1 ) ( figure 1 ) . in eight ( 89% ) of these subjects , faf imaging improved detection and/or characterization of pathology versus color imaging . for example , in individuals with dr , faf identified a larger number of dot - blot hemorrhages and microaneurysms , and it was superior at outlining rpe disturbance compared to color imaging ( figures 2(a ) and 2(b ) ) . while only minor perifoveal rpe hypopigmentation was evident on the color image , we identified two patients with extensive focal rpe defects after faf imaging ( figures 2(c ) and 2(d ) ) . in the subject with amd , faf imaging provided more detail than color imaging in terms of the extent of rpe disturbance ( figures 2(e ) and 2(f ) ) . in an individual with chronic csr , although we were able to appreciate a circular lesion nasal to the fovea in the color photograph , the faf image was superior at characterizing the full extent of this lesion ( e.g. , rpe hyperfluorescence ) ( figures 2(g ) and 2(h ) ) . in the case of ocular trauma , extensive fibrosis was appreciated on color imaging , while faf imaging further delineated an extensive area of rpe degeneration ( figures 2(i ) and 2(j ) ) . the only pathologic finding that was better appreciated on color imaging was dme with extensive hard exudates that were not apparent on faf imaging ( figures 2(k ) and 2(l ) ) . based on these findings , seven ( 14% ) subjects were referred to a retinal specialist and two ( 4% ) to a primary ophthalmologist . all subjects were successfully imaged under the study conditions and none were referred for a dilated examination due to small pupil size . as far as we can discern , this is the first prospective pilot imaging study set out to determine the feasibility of integrating faf technology in a community - based ocular screening program . we postulated that correlation of color and faf imaging may allow for improved characterization of damage to the retina and rpe . tool in several retinal diseases / conditions , including amd , hydroxychloroquine toxicity , and serpiginous - like choroiditis [ 14 , 15 ] . logistically during our screening , the process was aided by the fact that the canon cx-1 camera comes specifically configured to perform color , faf , and other types of imaging . therefore , we did not have to be concerned about transporting an extra piece of equipment to our screenings ( which commonly occur in difficult to access locations such as basements or buildings without elevators ) , or decreasing the number of participants screened due to space restrictions . additionally , the inter - phased imaging software allowed for side - by - side viewing of color and faf fundus images , which aided in comparing and correlating the ocular findings . an average of 22 eyes were imaged , and 44 color and faf digital images were reviewed per hour . identification of vtds necessitating referral to a general or specialty ophthalmologist occurred in nine ( 18% ) individuals . in our previous studies , an average of 2630 eyes was imaged per hour and the rate of vtd detection was 1030% ; however , neither of these studies employed two different types of imaging modalities [ 11 , 16 ] . of the nine ( 18% ) individuals with identified vtds in our current study , only seven ( 14% ) would have been referred for a comprehensive examination based on results of color fundus imaging ( excluding the two participants with focal rpe defects ) . thus , in addition to improved characterization of pathology identified on color fundus imaging , incorporation of faf imaging as a complementary technology in this cohort increased ocular pathology detection in our screenings by 29% ( from seven to nine eyes with pathology ) .   in the present study , we were able to show successful integration of faf imaging in a community - based ocular screening program . the imaging itself was simple to perform and it resulted in enhanced detection of abnormalities in a wide variety of retinal diseases when performed side - by - side with color fundus imaging . some of the potential limitations to using faf technology in screenings include : ( a ) increased cost of the faf camera versus a color fundus camera ; ( b ) increased screening time to allow for reversal of pupil constriction secondary to higher flash intensity required to acquire faf images ; ( c ) our currently limited understanding of the utility of faf in certain vtds like glaucoma and dr ; ( d ) requirement of patient cooperation and clear ocular media ( e.g. , without a visually significant cataract or vitreous opacity ) in order to obtain high - quality images ; and ( e ) potential difficulty with image interpretation due to absence of standardized equipment , protocols , and grading systems . a cost - benefit analysis , including the final impact on local health indicators , should be pursued . although the faf capable camera used in the present study is more expensive than a conventional color fundus camera , the potential of faf to improve ocular disease detection warrants further study . this may be especially pertinent for retina specialists for the diagnosis , detection of progression , anticipation of prognosis , and treatment of amd , dme , and so forth . earlier detection may positively impact the exorbitant costs attributable to undiagnosed ocular diseases such as amd , glaucoma , and dr [ 1720 ] . future work correlating faf findings with optical coherence tomography may enhance evaluation of diseases that damage the retina , rpe , and choroid , thereby potentially avoiding false positive referrals . based on our findings , we believe that faf imaging is a complementary technology that may have a significant impact on teleophthalmology applications . advances in imaging technologies make screening for vtds more accurate by employing complementary imaging technologies such as color fundus imaging , software - assisted analysis , and faf . in the current study , the number of subjects allowed for a descriptive analysis only . a larger follow - up study designed to compare the sensitivity , specificity , and positive and negative predictive values for vtd detection with and without the incorporation of faf is warranted . more specifically , a prospective , double - armed sequential screening study in which referral patterns based on color fundus imaging only versus color fundus imaging followed by faf imaging should be performed . the potential impact of improved characterization and detection of ocular pathology on disease burden ( including cost to society ) warrants further investigation . as a corollary , we believe that it would be pertinent to conduct cost analysis studies in order to make recommendations regarding the economic feasibility of incorporating faf imaging in ocular screening programs .
purpose . to describe integration of fundus autofluorescence ( faf ) imaging into an ocular screening program 
 . methods . 
 fifty consecutive screening participants were included in this prospective pilot imaging study . 
 color and faf ( 530/640  nm exciter / barrier filters ) images were obtained with a 15.1mp canon nonmydriatic hybrid camera . 
 a clinician evaluated the images on site to determine need for referral . 
 visual acuity ( va ) , intraocular pressure ( iop ) , and ocular pathology detected by color fundus and faf imaging modalities were recorded . 
 results . 
 mean  sd age was 47.4  17.3 years . 
 fifty - two percent were female and 58% african american . 
 twenty - seven percent had a comprehensive ocular examination within the past year . 
 mean va was 20/39 in the right eye and 20/40 in the left eye . 
 mean iop was 15  mmhg bilaterally . 
 positive color and/or faf findings were identified in nine ( 18% ) individuals with diabetic retinopathy or macular edema ( n = 4 ) , focal rpe defects ( n = 2 ) , age - related macular degeneration ( n = 1 ) , central serous retinopathy ( n = 1 ) , and ocular trauma ( n = 1 ) . conclusions . 
 faf was successfully integrated in our ocular screening program and aided in the identification of ocular pathology . 
 larger studies examining the utility of this technology in screening programs may be warranted .