While biological sex, living place, axial length, lens thickness, and mean keratometry are among the main associated factors with macular thickness, a population-based study published in Retina shows that macular thickness is slightly higher in Iranian children compared with similar populations. The researchers also note a higher cube volume and central macular thickness in rural populations compared with urban dwelling participants. 

Researchers used measurements of visual acuity, biometry, subjective and cycloplegic refraction, and optical coherence tomography (OCT) to analyze 5043 right eyes (mean age 12.39±1.72 years, 2704 boys, 2339 girls). The study shows central macular thickness was 239±19.35 μm. The mean cube volume and cube thickness was 9.94±0.44 and 278±12.20, respectively. Multiple linear regression analysis shows the central macular thickness to be significantly lower in girls (coefficient (β): -9.18; P <.001) and rural students (β: 3.86; P <.001) and had a direct association with axial length (β: 5.19; P <.001), lens thickness (β: 5.33; P =.003), and mean keratometry (β:2.41; P <.001). The cube volume was lower in girls (β: -0.13; P <.001) and rural area (β: 0.05; P <.001). 

 “Assessment of macular morphology and structure plays a significant role in diagnosis and classification of many ocular and systemic diseases affecting the retina,” according to investigators. More comprehensive knowledge of normal retinal morphology and characteristics as well as its changes in children and adolescents is therefore of “paramount importance.”


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Study limitations include a lack of information about birth of the studied population (term or preterm birth) as well as the fact that participants were limited to 1 city in Iran, where the main ethnic group is Persian. Researchers urge caution in generalizing these results to other communities.

These observed differences point up the importance of normative value in different populations. “Since most of the ophthalmologists use the values presented by the device for comparison as normal values, it is important to have an estimation of these values in different populations across the world,” note researchers of this study to be published in Retina. The first report of normative distribution thickness and volume in a large sample of Iranian children aged 9-15 using Spectral Domain optical coherence tomography (SD-OCT) provides helpful information about biometric and demographic factors.

Researchers hope that the normative thickness in this large population-based sample of children will be used to build a more comprehensive database of OCT results in children aged 10-15 years. 

Reference

Hashemi H, Khabazkhoob M, Heydarian S, Emamian MH, Fotouhi A. Macular thickness by SD-OCT in children and adolescents. Retina. Published online April 6, 2022. doi:0.1097/IAE.0000000000003484