Acta OphthalmolOctober 201614 citations

Distribution of intraocular pressure, central corneal thickness and vertical cup-to-disc ratio in a healthy Iranian population: the Yazd Eye Study.

Pakravan Mohammad, Javadi Mohammad Ali, Yazdani Shahin, Ghahari Elham, Behroozi Zohreh, Soleimanizad Reza, Moghimi Sasan, Nilforoushan Naveed, Zarei Reza, Eslami Yadollah

View on PubMed DOI: 10.1111/aos.13231

AI Summary

This study found average IOP, CCT, and VCDR values in healthy Iranians, differing from other ethnicities. Clinically, these population-specific norms are crucial for accurate glaucoma diagnosis and management.

Abstract

Purpose

To determine the distribution of intraocular pressure (IOP), central corneal thickness (CCT) and vertical cup-to-disc ratio (VCDR) in the healthy Iranian population.

Methods

This population-based, epidemiologic study evaluated Iranian aged 40-80 years, residing in Yazd, Iran, in 2010-2011. Eligible subjects were selected by cluster random sampling. Each participant underwent an interview and ophthalmologic examination including slit lamp examination, Goldmann applanation tonometry, binocular optic disc evaluation, stereoscopic fundus photography, ultrasonic pachymetry and visual field testing.

Results

Of 2320 eligible individuals, 2098 subjects (response rate of 90.4%) participated in the study. One eye from 1159 subjects (total of 2262 normal eyes) were randomly selected for the purpose of the study. Mean age was 53.1 ± 9.6 years. Mean IOP, CCT and VCDR were 14.2 ± 2.5 mmHg, 543 ± 37 μm and 0.32 ± 0.14, respectively. Multiple regression analysis showed a significant correlation between IOP and age (regression coefficient = 0.02 per year, p = 0.015), CCT (regression coefficient = 0.02 per micron, p < 0.001), Spherical equivalent (regression coefficient = -0.15 per dioptre, p = 0.0.024) and smoking (regression coefficient = 0.89 higher for smokers, p = 0.009); it also showed a significant correlation between CCT with spherical equivalent (regression coefficient = 3.6 per dioptre, p = 0.002) and IOP (regression coefficient = 3.6 per mmHG, p < 0.001). There was no significant correlation with VCDR.

Conclusions

Mean IOP, CCT and VCDR were 14.2 ± 2.5 mmHg, 543 ± 35 μm and 0.32 ± 0.14, respectively, in healthy Iranians that is different from other ethnicities. It seems advisable to pay attention to ethnicity for interpretation of each person's variables.

MeSH Terms

AdultAgedAged, 80 and overCorneaCross-Sectional StudiesFemaleGlaucomaGonioscopyHumansIncidenceIntraocular PressureIranMaleMicroscopy, AcousticMiddle AgedOptic DiskReference ValuesRetrospective StudiesRisk Factors

Shields Classification

Ch. 2Intraocular Pressure and Tonometry

Ch. 4Optic Nerve, Retina, and Choroid

Ch. 9Clinical Epidemiology of Glaucoma

Key Concepts5

In a healthy Iranian population aged 40-80 years, the mean intraocular pressure (IOP) was 14.2 2.5 mmHg.

EpidemiologyCross-sectionalPopulation-based, epidemiologic studyn=2098 subjects (2262 normal eyes)Ch3Ch10

In a healthy Iranian population aged 40-80 years, the mean central corneal thickness (CCT) was 543 37 m.

EpidemiologyCross-sectionalPopulation-based, epidemiologic studyn=2098 subjects (2262 normal eyes)Ch3Ch10

In a healthy Iranian population aged 40-80 years, the mean vertical cup-to-disc ratio (VCDR) was 0.32 0.14.

EpidemiologyCross-sectionalPopulation-based, epidemiologic studyn=2098 subjects (2262 normal eyes)Ch5Ch10

Multiple regression analysis in a healthy Iranian population aged 40-80 years showed a significant correlation between intraocular pressure (IOP) and age (regression coefficient = 0.02 per year, p = 0.015), central corneal thickness (CCT) (regression coefficient = 0.02 per micron, p < 0.001), Spherical equivalent (regression coefficient = -0.15 per dioptre, p = 0.024) and smoking (regression coefficient = 0.89 higher for smokers, p = 0.009).

PrognosisCross-sectionalPopulation-based, epidemiologic studyn=2098 subjects (2262 normal eyes)Ch3Ch10

Multiple regression analysis in a healthy Iranian population aged 40-80 years showed a significant correlation between central corneal thickness (CCT) with spherical equivalent (regression coefficient = 3.6 per dioptre, p = 0.002) and intraocular pressure (IOP) (regression coefficient = 3.6 per mmHG, p < 0.001).