night blindness occurs in response to a decrease in rhodopsin in retinal light - sensitive rod cells .
night blindness is usually due to retinitis pigmentosa , which is an inherited disorder ( 1 ) .
rhodopsin also decreases in response to vitamin a deficiency ( vad ) ( 2 ) . according to a world health organization (
who ) report , the prevalence of night blindness in iran is moderate ( more than 1% and less than 5% in pre - school age children ) . but this prevalence is highly variable in different areas of iran because of different nutritional situations ( 3 ) .
it is well known that vad is associated with a higher prevalence of night blindness and eye disorders ( 4 ) .
xerophthalmia is advanced form of vitamin a deficiency that is associated with dry and unclear conjunctiva ( 5 , 6 ) .
photosensitivity , decreased tearing , ulcers , and infection are also more prevalent in these patients .
studies in iran have shown a high prevalence of vad among pregnant women in hormozgan , which is an important health issue in this province ( 7 ) .
the prevalence of night blindness is classically an indicator of nutritional and vitamin a deficiency situations .
the aim of the current study is to assess the prevalence of night blindness in bashagard in 2011 .
this descriptive cross - sectional study was done in the winter of 2011 in the bashagard district , located in hormozgan province .
considering the prevalence of night blindness in different studies ( 2% ) and a confidence interval of 95% , a sample size of 819 was selected . considering the geographical diversity of the bashagard district , cluster sampling
therefore , the calculated sample size was divided between the covered populations of five health centers ( goharan , tisoor , tidar , sar dasht , and jakdan ) .
a checklist ( including demographic data such as name , family name , place of residence , covering health center , sex , age , and educational level ) was used to collect the data . in the second section
the data about the duration of the disease and treatments received for the disease were also recorded .
the third section concerned the patient s history of eye trauma , surgery , and ophthalmic infection . in the final section
, some questions about nutrition and meat , fruit , and vegetable consumption were asked .
table 1 shows the frequency and percentage of the studied people in each of the five health centers . among the 814 people studied , 32 had disturbances in their vision at night .
the youngest individual with night blindness was 5 years old and the oldest one was 70 years old .
twelve people in tidar , ten in sar dasht , eight in jakdan , one in goharan , and one in tisoor had night blindness .
therefore , the prevalence of night blindness in males and females was 3.4% and 4.4% , respectively .
the mean duration of the disease was 2.5 years . among all patients , two ( 6.25% ) had physician visits and were using drugs for their disease .
another four ( 12.5% ) had physician visits and were using glasses for their disease .
one ( 3.1% ) had a history of eye trauma , another one ( 3.1% ) had a history of eye infection , and one ( 3.1% ) also had a history of eye surgery .
twenty - one patients ( 65.6% ) had nt met the daily recommended consumption of fruits and vegetables , one ( 3.1% ) had nt even met the once - a - week recommended meat consumption , and three ( 9.4% ) had nt met the twice - a - week milk and dairy recommended consumption . among the 814 people studied , seventy - four were 2 to 6 years old ; among them , one ( 1.4% ) had night blindness . of 341 women between 15 to 49 years old , six among them ( 1.8% ) had night blindness .
one of the most important known etiologies is vitamin a deficiency ( 8) . according to who statistics
, the prevalence of night - blindness is less than one percent , meaning a mild to moderate prevalence ( 9 ) . in the current study , we found that the prevalence of night - blindness is 3.93% in bashagard , which is three times greater than the average national prevalence .
the prevalence of visual disorders and ophthalmic diseases are higher in this province , which may be due to vitamin a deficiency .
the prevalence of night blindness in beshno and cistomacity ( 9.43% and 9.45% , respectively ) indicates a higher prevalence in some areas of bashagard , which calls for immediate action .
vitamin a plays a vital role in prevention of the disease and development , in addition to its role in the visual system .
it is especially important in children 2 to 6 years old and pregnant women ( 10 ) .
another important point in this study was that about 60% of the participants are non - educated .
therefore , they have a low socioeconomic level and need support and attention . according to who indexes ,
vitamin a deficiency is a important health issue in areas with a prevalence of 1 to 5 percent of night blindness ( 9 ) .
therefore , our findings show that vitamin a deficiency is an important health issue in bashagard .
vitamin a deficiency in rural areas and towns in hormozgan is shown in previous studies and needs the attention of health system policy makers .
it is shown that vitamin a supplementation and nutrients and also diet changes in the areas with significant levels of vitamin a deficiency can significantly decrease ophthalmic and visual problems .
in this study , the initial assessment of a health issue problem in bashagard was done .
we recommend other studies on the measurement of vitamin a serum level , ophthalmic assessment , and specific tests and interventions in the study population .
 background : night blindness is a visual disorder associated with unusual vision during the night or in darkness . vitamin a deficiency ( vad ) , which is easily preventable , is the main known etiology of night blindness . 
 malnutrition is a common health issue in bashagard and some other areas in the hormozgan province of iran . 
 the aim of the current study was to determine the prevalence of night blindness in bashagard.methods:this descriptive cross - sectional study was done on 814 bashagard residences . 
 data was analyzed using spss software and descriptive studies.results:about 60% of the study participants were uneducated people or people with low education . 
 thirty - two out of 814 people that were studied had problems with night vision . 
 therefore , the prevalence of night blindness in bashagard was 3.93%.conclusion : prevalence of night blindness in bashagard is three times higher than its prevalence in all of iran . 
 therefore , preventive interventions such as dietary regimes with vitamin a enrichments or supplementations are recommended . 
Introduction
Materials and Methods
Results
Discussion
Conclusion