The Distribution of Macular Thickness and Its Determinants in a Healthy Population.
To determine the distribution of macular thickness in a healthy Iranian population aged 45-69 years and its association with certain determinants.



All participants underwent optometric examinations including measurement of uncorrected and corrected visual acuity, objective refraction by retinoscopy, and subjective refraction. Subsequently, all participants underwent slit-lamp biomicroscopy followed by fundus examination through direct and indirect ophthalmoscopy, and optical coherence tomography (OCT) imaging under pupil dilation.



Mean central macular thickness was 255.4 µm (95% confidence interval, CI, 254.5-256.3 µm), average inner macular thickness was 316.5 µm (95% CI 315.9-317.1 µm), average outer macular thickness was 275.3 µm (95% CI 274.8-275.8 µm), and overall average thickness was 278.6 µm (95% CI 278.1-279.1 µm). A linear multiple regression model showed that all indexes were significantly larger in male participants (p < 0.001). Central macular thickness increased with age (coef = 0.25, p < 0.001) while overall, inner and outer macular thickness decreased with age (coef = -0.18, -0.15, -0.19, respectively, all p < 0.001). Central and inner macular thickness had a positive correlation (coef = 3.8, 2.6, respectively, both p < 0.001) and outer macular thickness had a negative correlation (coef = -1.6, p < 0.001) with axial length.



Age, sex, refractive error, axial length, and keratometry were found to be associated with macular thickness. These factors should be taken into account when interpreting macular thickness measurements with spectral-domain OCT.
a Noor Research Center for Ophthalmic Epidemiology, Noor Eye Hospital , Tehran , Iran.|b Noor Ophthalmology Research Center, Noor Eye Hospital , Tehran , Iran.
Hassan
H
Hashemi
c Department of Medical Surgical Nursing, School of Nursing and Midwifery , Shahid Beheshti University of Medical Sciences , Tehran , Iran.
Mehdi
M
Khabazkhoob
d Department of Optometry, School of Paramedical Sciences , Mashhad University of Medical Sciences , Mashhad , Iran.
AbbasAli
A
Yekta
e Center for Health Related Social and Behavioral Sciences Research , Shahroud University of Medical Sciences , Shahroud , Iran.
Mohammad Hassan
MH
Emamian
b Noor Ophthalmology Research Center, Noor Eye Hospital , Tehran , Iran.
Payam
P
Nabovati
f Department of Epidemiology and Biostatistics, School of Public Health , Tehran University of Medical Sciences , Tehran , Iran.
Akbar
A
Fotouhi
D000367:Age Factors; D000368:Aged; D058452:Axial Length, Eye / Q000033:anatomy & histology; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007492:Iran; D008266:Macula Lutea / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology; D012044:Regression Analysis; D012737:Sex Factors
Adult; macular thickness; ocular biometry; population-based study; refractive errors