***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: PURPOSE Dry eye syndrome ( DES ) is believed to be one of the most common ocular problems in the United States ( US ) , particularly among older women . However , there are few studies describing the magnitude of the problem in women and how this may vary with demographic characteristics . DESIGN Cross-sectional prevalence survey . METHODS STUDY POPULATION we surveyed 39,876 US women participating in the Women 's Health Study about a history of diagnosed DES and dry eye symptoms . MAIN OUTCOME MEASURE we defined DES as the presence of clinical ly diagnosed DES or severe symptoms ( both dryness and irritation constantly or often ) . We calculated the age-specific prevalence of DES and adjusted the overall prevalence to the age distribution of women in the US population . We used logistic regression to examine associations between DES and other demographic factors . RESULTS The prevalence of DES increased with age , from 5.7 % among women < 50 years old to 9.8 % among women aged > or = 75 years old . The age-adjusted prevalence of DES was 7.8 % , or 3.23 million women aged > or = 50 in the US . Compared with Whites , Hispanic ( odds ratio [ OR ] = 1.81 , confidence interval [ CI ] = 1.18 - 2.80 ) and Asian ( OR = 1.77 , CI = 1.17 - 2.69 ) women were more likely to report severe symptoms , but not clinical ly diagnosed DES . There were no significant differences by income ( P([trend ] ) = .78 ) , but more educated women were less likely to have DES ( P([trend ] ) = .03 ) . Women from the South had the highest prevalence of DES , though the magnitude of geographic differences was modest . CONCLUSIONS Dry eye syndrome leading to a clinical diagnosis or severe symptoms is prevalent , affecting over 3.2 million American women middle-aged and older . Although the condition is more prevalent among older women , it also affects many women in their 40s and 50s . Further research is needed to better underst and DES and its impact on public health and quality of life PURPOSE To examine whether low-dose aspirin ( 325 mg on alternate days ) reduces the risk of  age-related cataract and subtypes . This report extends previous findings , including both subtypes and additional newly identified incident cases since the earlier report . METHODS All 20,979 participants in the Physicians ' Health Study , a r and omized trial of aspirin and beta-carotene among U.S. male physicians age 40 - 84 in 1982 , who did not report cataract at baseline were included . Average follow-up was five years . The main outcome measure was incident , age-related cataract responsible for a reduction in best-corrected visual acuity to 20/30 or worse , based on self-report confirmed by medical record review . RESULTS 501 age-related cataracts were diagnosed during follow-up , including 416 with nuclear sclerosis and 212 with a posterior subcapsular component ; 318 cataracts progressed to surgical extraction . Overall , there were 245 cataracts in the aspirin group and 256 in the placebo group ( relative risk [ RR ] , 0.94 ; 95 % confidence interval [ CI ] , 0.79 to 1.13 ; P = 0.52 ) . Cataract extraction s were 19 % less frequent in the aspirin than in the placebo group ( RR , 0.81 ; 95 % CI , 0.65 to 1.01 ; P = 0.06 ) . In subgroup analyses of subtypes , aspirin takers had a lower risk of posterior subcapsular cataract ( RR , 0.74 ; 95 % CI , 0.57 to 0.98 ; P = 0.03 ) but not nuclear sclerosis ( RR , 0.96 ; 95 % CI , 0.79 to 1.16 ; P = 0.65 ) cataract . CONCLUSIONS Overall , these r and omized trial data tend to exclude a large benefit of five years of low-dose aspirin therapy on cataract development and extraction . The data are compatible with a modest benefit on cataract extraction for this duration of aspirin therapy . Subgroup analyses raise the possibility of a modest , but potentially important , protective effect of aspirin on posterior subcapsular cataract , a particularly disabling subtype Purpose To assess the additive effect of diquafosol tetrasodium on sodium hyaluronate monotherapy in patients with dry eye syndrome . Methods This study evaluated 64 eyes of 32 patients ( age : 62.6±12.8 years ( mean±SD ) ) in whom treatment with 0.1 % sodium hyaluronate was insufficiently responsive . The eyes were r and omly assigned to one of the two regimens in each patient : topical administration of sodium hyaluronate and diquafosol tetrasodium in one eye , and that of sodium hyaluronate in the other . Before treatment , and 2 and 4 weeks after treatment , we determined tear volume , tear film break-up time ( BUT ) , fluorescein and rose bengal vital staining scores , subjective symptoms , and adverse events . Results We found a significant improvement in BUT ( P=0.049 , Dunnett test ) , fluorescein and rose bengal staining scores ( P=0.02 ) , and in subjective symptoms ( P=0.004 for dry eye sensation , P=0.02 for pain , and P=0.02 for foreign body sensation ) 4 weeks after treatment in the diquafosol eyes . On the other h and , we found no significant change in these parameters after treatment in the control eyes . Conclusions In dry eyes , where sodium hyaluronate monotherapy was insufficient , diquafosol tetrasodium was effective in improving objective and subjective symptoms , suggesting its viability as an option for the additive treatment of such eyes Purpose : The aim of this study was to evaluate the treatment effect of diquafosol 3 % with preservative-free sodium hyaluronate 0.1 % eye drops in dry eye syndrome . Methods : In total , 150 patients with dry eye syndrome were divided r and omly into 3 groups . Group 1 ( 50 patients ) was treated 4 times daily with preserved sodium hyaluronate 0.1 % , group 2 ( 50 patients ) was treated 4 times daily with diquafosol 3 % , and group 3 ( 50 patients ) was treated 4 times daily with diquafosol 3 % and preservative-free sodium hyaluronate 0.1 % eye drops for 3 months . Ocular surface disease index ( OSDI ) score , tear film break-up time , Schirmer I test , corneal fluorescein staining , and impression cytology were evaluated . Results : There were significant improvements in the OSDI score , tear film break-up time , Schirmer I score , fluorescein and Rose Bengal staining , goblet cell density , and impression cytological findings in groups 2 and 3 compared with those for group 1 in patients with dry eye syndrome at 1 , 2 , and 3 months ( P < 0.05 ) . There were statistically significant improvements in the OSDI score ( −8.48 ± 0.97 , −5.69 ± 0.78 ; P = 0.02 ) , fluorescein ( −1.43 ± 0.21 , −1.02 ± 0.18 ; P = 0.03 ) , and Rose Bengal staining ( −1.12 ± 0.26 , −0.75 ± 0.12 ; P = 0.03 ) , goblet cell density ( 89.65 ± 14.39 , 70.36 ± 16.75 ; P = 0.03 ) , and impression cytological findings ( −0.53 ± 0.12 , −0.34 ± 0.90 ; P = 0.01 ) in group 3 compared with those in group 2 at 3 months . Conclusions : Treatment with diquafosol 3 % with preservative-free sodium hyaluronate 0.1 % was more effective than diquafosol 3 % monotherapy or treatment with preserved sodium hyaluronate 0.1 % in dry eye syndrome . Preservative-free sodium hyaluronate 0.1 % eye drops can increase the effect of diquafosol 3 % in dry eye syndrome Activation of P2Y2 receptors in various tissues results in secretion of ions , fluid and mucin . In situ hybridization experiments on fresh primate tissue confirm the presence of mRNA coding for the gene expression of the P2Y2 receptor in the conjunctiva and the meibomian gl and . Topical ocular administration of nucleotides causes increased chloride and mucin secretion , as well as fluid transport . These pharmacologic findings lead to the hypothesis that P2Y2 receptor agonists may have therapeutic efficacy in diseases of impaired ocular hydration Purpose : To investigate the effects of diquafosol sodium ( DQS ) eye drops , a purinergic P2Y2 receptor agonist , on tear film stability in patients with unstable tear film ( UTF ) . Methods : Two prospect i ve studies were conducted . One was an exploratory nonr and omized trial on 39 eyes with dry eye symptoms and short tear film break-up time ( BUT ) , but without epithelial damage .  Changes in symptoms , BUT , Schirmer value , and ocular surface fluorescein staining ( FS ) scores were studied for 3 months . The other was a r and omized clinical trial of DQS and artificial tears ( AT ) in 17 eyes with short BUT . Eyes with decreased Schirmer values ( ⩽5 mm ) were excluded . Changes in symptoms , BUT , FS scores , and tear film stability using continuous corneal topographic analysis were studied for 4 weeks . Results : In the exploratory study , while Schirmer values were not significantly increased , significant improvements in symptoms and BUT were noted at both 1 and 3 months . In the r and omized clinical trial , significant improvements in symptoms were noted in the DQS group , but not in the AT group , at 2 weeks . BUT was significantly prolonged in the DQS group at 4 weeks but not in the AT group . No significant changes were noted in FS scores or tear film stability . Conclusions : DQS improved subjective symptoms and prolonged BUT in eyes with UTF not associated with low tear secretion and ocular surface epithelial damage . Because many patients who have UTF are refractory to conventional treatments , DQS may offer benefits in the treatment of dry eyes 
    Output:
    
Topical diquafosol seems to be a safe therapeutic option for the treatment of dry eye .
However , the topical administration of diquafosol seems to be beneficial in improving the integrity of the epithelial cell layer of the ocular surface and mucin secretion in patients with dry eyes .