Global metrics on ocular biometry: representative averages and standard deviations across ten countries from four continents

Abstract

Background/Objectives We provide global averages and standard deviations for ocular biometry—axial length (AL), corneal radius of curvature (CR), anterior chamber depth (ACD), lens thickness (LT), white to white (WTW), and central corneal thickness (CT). We hope a better understanding of normal and abnormal values will help clinicians gain further insight into their surgical outcomes, especially for off-target eyes. Subjects/Methods We searched the MEDLINE database using keywords “axial length, corneal power, anterior chamber depth, lens thickness, white to white, and corneal thickness.” We included studies that reported averages and standard deviations on eye biometry for at least 1300 eyes. Global weighted averages and standard deviations were calculated using the Cochrane method. Results Fourteen studies were included, originating from Asia (Japan, Singapore, Myanmar, Iran, South Korea, China), Europe (Germany, United Kingdom, Portugal), Australia, and North America (United States). Global ocular biometry metrics were: AL—23.49 mm ± 1.35 mm, CR—7.69 mm ± 0.28 mm, ACD—3.10 mm ± 0.47 mm, WTW—11.80 mm ± 0.42 mm, LT—4.37 mm ± 0.43 mm, and CT—544 μm ± 38 μm. Total eyes per value ranged from 19,538 to 90,814. Conclusions We report global ocular biometry averages and standard deviations. No eyes were from studies in Africa or South America, highlighting the need to publish eye biometry data from these continents. We hope that promoting a deeper understanding of biometry values will help clinicians gain insight into surgical outcomes and drive innovations in lens calculations.

Comparison Between Ocular Biometric Parameters and Intraocular Pressure With and Without Contact Lenses

“…Since the corneal and CL thickness are usually recorded in the same magnitudes (mm), the sample size calculation was based on this parameter. Previous reports indicate that the mean SDs of CCT are usually distributed with a value of 38 mm, 20 whereas the lowest value of the CL thickness used in this study was 80 mm (Table 1). Based on those data, to have 90% power (type II error associated) for a significance level of ?¼0.05 (type I error associated) with a confidence level of 95% to detect a clinical difference between values with and without CL, the minimum number of subjects required was six per group; since two different CLs were used in a paired analysis, a minimum of 12 participants are needed in the final study group to avoid statistical interference.…”

Gender‐ and Age‐Related Differences of Ocular Biometric Parameters in Patients Undergoing Cataract Surgery in Bosnia and Herzegovina

“…The results of recent studies presented significant racial differences. Studies from Asian and Hispanic populations have presented longer axial length than European populations [ 33 ]. All patients in our study were of European origin, [ 23 ] and our biometric results are the closest to those from Germany [ 7 ] and Slovakia [ 20 ].…”

Ocular parameters and anthropometry in Indo-Trinidadians

“…Also, disparity in the type of instrument used for the measurement could have influenced the result recorded like use of A scans were reported to have a shorter axial length when compared to the use of optical low-coherence reflectometry, which gives longer Als. [19] Moreover, variations in the size of globes for males and females of other races including Caucasians and African which is not the case in Asians (Japanese, Chinese) could be the reason for the longer AL measured among males than females. [20] The steeper corneal curvature and smaller WTW corneal diameter recorded in the current study among females are expected, as taller people are reported to have longer eyes, deeper anterior chamber depths, and flatter corneal curvature radii.…”