  age - related macular degeneration ( amd ) is the most common cause of blindness in industrialized countries affecting individuals over the age of 55 .
neovascular amd affects only 1015% of amd patients but approximately 90% of blindness due to this condition . the main cause of vision loss in neovascular amd is the development of choroidal neovascularization , which is ultimately the result of a break in a structural layer beneath the retina known as bruch 's membrane , which separates the nourishing vascular layer called the choroid from the retina .
these vessels can leak fluid or blood , initially distorting or blurring vision , and may eventually lead to scar in the macula and severe loss of central vision .  
erectile dysfunction ( ed ) is defined as the inability to attain or maintain the penile erection required for sufficient sexual performance .
ed is a multifactorial disease ; the vascular , neurogenic , hormonal , psychogenic , cavernosal , iatrogenic , and anatomic causes lie in its pathophysiology .
the impact of ed can be devastating because evidence has shown that sexual function is one of the very important indices of quality of life .  
cross - sectional studies have reported that ed is strongly associated with diabetes mellitus , hypertension , cardiovascular disease , hyperlipidemia , metabolic syndrome , depression , and lower urinary track symptoms [ 915 ] .
medication and recreational drugs are also associated with male sexual disorders , especially the use of antipsychotic drugs .
new epidemiological studies show an increase in the prevalence rates for ed in men who smoke as a standalone risk .
also , obesity , low testosterone levels , poor quality of life , apnoea - hypopnoea , and obstructive sleep apnoea syndrome were significantly associated with a higher risk of ed . to the best our knowledge , the association between neovascular amd and ed has not been evaluated before . in this cross - sectional study , we aim to investigate the relationship between ed and neovascular amd .
  this prospective , cross - sectional study was conducted at the ophthalmology clinic between december 2012 and march 2013 .
the study was conducted according to the declaration of helsinki , the european guidelines on good clinical practice , and relevant national and regional authority requirements and the university 's ethics committees . all subjects signed informed consent forms before participating in the study .   
ninety sexually active men with neovascular amd ( group 1 ) , who presented to our clinic , enrolled in the study . the control group ( group 2 ) was formed with the participation of 105 randomly chosen healthy volunteers from among those in the outpatient clinic .
patients with diabetes mellitus , hypertension , hyperlipidemia , heart disease , or other known systemic diseases ( such as depression , stroke , and medications ) and/or smokers were excluded .   
the international index of erectile function ( iief ) is a widely used , multidimensional self - report instrument for the evaluation of male sexual function .
the presence and severity of ed were determined by calculating the ef domain of the questionnaire ( ef score ) . because we aimed to evaluate ef
the responses to all the six questions of the ef domain were added to arrive at a total ef score , with a range from six to 30 .
the six items on the ef domain include detailed questions concerning erection frequency , erection firmness , penetration ability , maintenance frequency , maintenance ability , and erection confidence .
ed severity was rated as no ed if scored from 26 to 30 , mild ed if scored from 17 to 25 , moderate ed if scored from 11 to 16 , and severe ed if scored from 6 to 10 .   
we separated the patients according to their binocular vision ( low vision or not ) and patients were divided into two groups with or without binocular vision higher than 0.3 .
amd was diagnosed with fundoscopic retinal examination , fundus fluorescein angiography , and optical coherence tomography .   
data analysis was performed with spss ( statistical package for social sciences ) , version 17.0 .
the kolmogorov - smirnov test was used to assess the normality of numeric variables . for the normally distributed variables , comparison between the two groups
was made by the independent sample t test and one - way anova , and the results were expressed as mean  standard deviation . for the nonnormally distributed variables , comparison between two groups
was made by the mann whitney u - test and the descriptive statistics were expressed as median ( 2575 percentiles ) .
  demographic characteristics of participants for both groups are presented in table 1 . in group 1 , there were 90 men with a mean age of 62 years , ranging from 54.5 to 73 . in group 2 , there were 105 men with a mean age of 60 years , ranging from 54 to 68 . 

the results of the ef domain score revealed that 50 patients ( 55.6% ) had severe ed , 20 patients ( 22.2% ) had moderate ed , 15 patients ( 16.7% ) had mild ed , and 5 patients ( 5.6% ) had no ed . in group 2 , the results of the patients ' ef domain score revealed that 33 ( 31.4% ) had severe ed , 16 ( 15.2% ) had moderate ed , 19 ( 18.1% ) had mild ed , and 37 ( 35.2 % ) had no ed .
patients with neovascular amd had a significantly higher incidence of ed than control patients ( p < 0.01 ) .
there was a significant association between ed and neovascular amd ( p < 0.01 ) .   according to binocular vision classifications
, there were 49 and 98 men whose binocular vision was higher than 0.3 in groups 1 and 2 , respectively .
similarly , there were 41 and 7 men with a binocular vision of 0.3 or lower in groups 1 and 2 , respectively . in group 1 ,
97.6% of the subjects with binocular vision of 0.3 or lower had ed . in group 2 , all of the participants with binocular vision of 0.3 or lower had ed .
62.2% of controls with good vision ( va > 0.3 ) had ed , while 91.8% of amd patient with good vision had ed .
there was no statistically significant difference according to ed and visual level in neovascular amd group ( p = 0.16 ) .
conversely , in control group , the difference was statistically significant ( p = 0.03 ) ( figure 2 ) .  
bmi was calculated ( kg / m ) and subjects were categorized as normal ( 22 to 24.9  kg / m ) , overweight ( 2529.9  kg / m ) , or obese ( 30  kg / m ) according to their bmi values .
mean bmi was 26.71  3.1 and 25.87  4.1 , in groups l and 2 , respectively .
there were 22 normal weight men , 53 overweight men , and 15 obese men in group 1 .
there were 47 normal weight men , 43 overweight men , and 15 obese men in group 2 .
93.3% of obese men , 94.7% of overweight men , and 95.5% of normal weight men were found to have ed in group 1 .    while in control group only 12 overweight subjects had severe ed in amd group , 33 overweight subjects ( nearly three times as many as controls ) had severe ed .
6 subjects had moderate ed , while in amd group 13 subjects had moderate ed ( p < 0.01 ) ( table 2 ) .  
we separated the subjects according to their ages . in group 1 , all subjects had ed in the 4th and 5th decades . in the 6th decade and over the age of 70 , 87.5% and 96.7% of patients had ed , respectively .
46.2% of patients in the 4th decade and 56.1% of patients in the 5th decade were found to have ed in group 2 . in the 6th decade and over the age of 70 , 71% and 85% of patients had ed , respectively ( table 3 ) .
the association between neovascular amd and ed has never been elucidated in the literature . in the present study
diabetes mellitus , hypertension , stroke , chronic kidney disease , atherosclerosis , abnormalities of lipid metabolism , hyperlipidemia , and cardiovascular disease are positively associated with amd [ 21 , 22 ] .
also , several studies have attempted to assess the relationship between ed and risk factors such as diabetes mellitus , depression , cardiovascular disease , smoking , hypertension , increased age , hypogonadism , hyperprolactinemia , and hyperparathyroidism .   in the control group among patients with no risk factors or any of the medical comorbidities
this prevalence and severity of ed seem to be high for controls . on the other hand ,
these results were found to be much more higher in neovascular amd group . in neovascular amd group among patients with no risk factors or any of the medical comorbidities
first , both choroid and penis have a rich vasculature and impaired microcirculation has been disclosed in the choroids of patients with neovascular amd and in the penises of men with ed [ 2224 ] .
second , some recent studies have demonstrated that disorders with endothelial dysfunction are associated with ed .
third , nitric oxide ( no ) is particularly important ; vasodilation is essential for erection , and no has the trigger role for vasodilation in the vascular endothelium .
several clinical trials have shown soluble markers related to endothelial dysfunction , for example , sicam-1 .
there is considerable evidence implicating endothelial dysfunction and cellular oxidative stress in the pathogenesis of both amd and ed .   
potential mechanisms include endothelial dysfunction , metabolic syndrome and diabetes , altered endocrine function , social and psychological problems , and obstructive sleep apnoea , as well as ordinary physical disabilities .
lifestyle factors such as smoking , high alcohol intake , poor diet , and physical inactivity may also influence sexual dysfunction [ 29 , 30 ] .
interestingly , these observations were not corroborated by paick et al . who did not find a significant relationship between ed severity and metabolic syndrome , bmi , hormones , lifestyle .
no associations were found for either men or women between bmi and sexual satisfaction within their relationship .   
our study revealed a statistically significant relationship between bmi and ed in control group ( p = 0.01 ) .
we also did not find any strong association between bmi and ed in neovascular amd group ( p = 0.121 ) .  
depression is characterized by loss of interest , reduction in energy , lowered self - esteem , and inability to experience pleasure .
this constellation of symptoms may be expected to produce difficulties in sexual relationships and depression has long been associated with sexual problems .
several studies indicate that low vision secondary to amd is a risk factor for depression and this has serious consequences for the quality of life among patients with amd .
depression and stress are also psychogenic factors of ed and stress - related characteristics are found in patients with amd .
augustin et al . found that the prevalence of depression increased as visual impairment became more severe .
rates ranged from 14.3% for those with minimal vision loss to 25% for those with severe vision loss .
the prevalence of depression was also high among older adults who sought low vision rehabilitation services .    in ophthalmology practice ,
if binocular vision is lower than 0.3 , it is called  low vision  .
low vision results in depression and connected with this ; depression also results in ed .
we separated the patients according to their binocular vision ( low vision or not ) and we could clarify if the ed is because of amd or low vision . in control group
those patients whose binocular vision was 0.3 or lower had a significantly higher incidence of ed than patients with good binocular vision .
interestingly , in neovascular amd group there was no association between visual levels and ed .  
tsai et al . demonstrated epidemiological evidence of a significantly increased ratio of ed among patients with central serous chorioretinopathy ( cscr ) diagnosis .
they claimed that some factors like glucocorticoids , microvascular pathologies , and endothelial dysfunction prone to inducing cscr could also have a harmful effect on ef .   
there are many similar risk factors between the etiology and pathogenesis of amd and ed . to the best of our knowledge
, this study is the first study that shows the association between neovascular amd and ed .
 
 purpose . to evaluate association between erectile dysfunction ( ed ) and 
 neovascular age - related macular degeneration ( amd ) . methods . 
 195 men enrolled in this cross - sectional study . 
 90 of them had neovascular amd and 105 of them were healthy volunteers . 
 the international index of erectile function ( iief ) questionnaire 's erectile function ( ef ) domain was used to assess ed . 
 the patients in the study and control groups were statistically compared according to visual acuity , ef score , and body mass index . 
 results . 
 the mean ages were 62 ( 54.573 ) and 60 ( 5468 ) , in the neovascular amd and control groups , respectively . 
 the total ef scores were 9 ( 616 ) in neovascular amd and 18 ( 9.527 ) in control group . 
 the results of iief questionnaire on neovascular amd patients revealed that 85 men ( 94.4% ) had some degree of ed , whereas 68 men ( 64.8% ) had some degree of ed on control group . 
 patients with neovascular amd had a significantly higher incidence of ed than control patients ( p < 0.01 ) . 
 there was a significant association between ed and neovascular amd ( p < 0.01 ) . 
 conclusions . 
 our results suggested that neovascular amd has a high association with ed . 
1. Introduction
2. Material and Methods
3. Results
4. Discussion