Differences in ocular biometry between urban and rural children matched by refractive error: the Shandong Children Eye Study

Abstract

Purpose To determine the differences in mean ocular dimensions between urban and rural children and identify possible influencing factors. Methods This work uses previously published data from the Shandong Children Eye Study, which was based on a random cluster sampling applied to a cross‐sectional school‐based study design in the rural Guanxian County and Weihai city. All children underwent auto‐refractometry and biometry under cycloplegia. Results The study included 3290 children (aged 9.35 ± 2.93 years), consisting of 888 pairs of boys and 757 pairs of girls matched by sex, age and refractive error (each pair matching one child from urban cohort with one from the rural cohort). Overall urban children were significantly taller and heavier than rural children (t‐test; p < 0.001), which was confirmed for all age groups for weight. Urban ocular axial lengths were significantly longer by 0.23 mm compared to the rural population (t‐test; p < 0.001), mostly in younger children and boys. Meanwhile, corneal curvatures were flatter in the urban cohort by 0.08 mm (p < 0.001). This association of axial length with urban vs rural region was reduced in magnitude by 69.7% after accounting for height. Conclusions For the same, matched refractive error, children from urban regions had significantly longer eyes and flatter corneal curvature than rural children. Since corneal curvature is defined during the first 2 years of life, early environmental factors may be the source of these differences in ocular dimensions.

Age‐related axial length changes in adults: a review

“…Both of these factors have changed dramatically in recent decades due to the gradual adoption of an urban lifestyle with a high calorie diet and a sedentary, indoors activity pattern. This results in noticeable differences in ocular biometry between emmetropic children in urban and rural areas 41 …”

“…[35][36][37] differences in ocular biometry between emmetropic children in urban and rural areas. 41 Although these observations make it clear that the observed axial length changes are largely due to a cohort effect, there are several other influences that affect axial length (measurements) which are discussed below.…”

Reappraisal of the historical myopia epidemic in native Arctic communities

“…This brought an epidemic of obesity, metabolic syndrome and diabetes that became famous in the history of medicine 45 – along with dental caries, anaemia, heart disease and cancers, which were rare among the Inuit prior to this dietary shift. While it may have seemed reasonable at the time, diet has long since been accepted as inconsequential in myopia development, 46,47 although it does play a role in overall eye size 48 …”

“…This brought an epidemic of obesity, metabolic syndrome and diabetes that became famous in the history of medicine45 -along with dental caries, anaemia, heart disease and cancers, which were rare among the Inuit prior to this dietary shift. While it may have seemed reasonable at the time, diet has long since been accepted as inconsequential in myopia development,46,47 although it does play a role in overall eye size 48. Health programmes, including transportation to hospitals, were developed further by government after 1970 and are still underway, this time with new approaches that include health education programmes and employ indigenous personnel 2.…”

Beijing Pinggu Childhood Eye Study: The Baseline Refractive Characteristics in 6- to 12-Year-Old Chinese Primary School Students

“…Evaluation of the prospective cross-sectional study refraction status of students under cycloplegia and non-cycloplegia, together with ocular biometry, will enhance our understanding of the myopia epidemic, especially in China. However, previous studies reported the individual ocular parameters separately ( 7 – 9 ), evaluated them with a non-cycloplegia situation ( 10 ), or reported narrow age results ( 1 ). In addition, several studies were conducted approximately 10 years ago ( 11 , 12 ).…”