Refractive development I: Biometric changes during emmetropisation

Abstract

Refractive development in utero is an impressive feat of prenatal growth as it brings the tiny infant eye to near hypermetropia without the assistance of a retinal image to guide visual development. After birth, the eye undergoes emmetropisation, a period during which most eyes see their cycloplegic refractive error evolve towards a value close to +1 D. Once this is reached, eye growth enters a phase of homeostasis when the eye continues to grow while maintaining its refractive error at mild hypermetropia through a gradual loss of crystalline lens power.Although emmetropisation was first described over 100 years ago by Straub, 1 its exact nature remains unclear. Straub and subsequent authors 2-4 knew that the refractive error could only be minimised if the refractive components of the eye could coordinate their growth rates, but there was no agreement on how this was accomplished.

Emmetropic eye growth in East Asians and non‐East Asians

“…Compared to males, females are known to have a shorter AL on account of their generally shorter stature (readers may refer to the discussion in Rozema 5 for a concise overview). Moreover, a general difference in AL growth rate may also exist between female and male emmetropes during childhood/puberty, given that changes in height and AL have been shown to be correlated in young emmetropes 10 .…”

“…Across ethnic groups, the annual growth rate decreases from 0.24 mm/year at age 6 to around 0.05 mm/year at age 11, after which it dips below the repeatability of optical biometry (around ±0.04 mm) 6 and is of little practical importance. Rozema 5 recently pooled myriad ocular biometric data from 294 studies, including eyes from the foetal period (preterm birth used as surrogate) to 20 years after birth, but without stratification by ethnicity. Primary studies that used participants above 7 years of age were carefully screened in that work to minimise the influence of myopia.…”

“…However, some gaps remain to be addressed. First, the employment of ocular ultrasonography by previous longitudinal studies 2,3 and several primary studies included in the meta‐regression 4,5 described above limited the precision of AL estimates in these works. Compared with optical biometry, ocular ultrasonography has significantly lower repeatability in normal children (−0.85 to +0.67 mm vs. −0.05 to +0.04 mm) 6 .…”

“…Earlier longitudinal studies that shed light on how AL changes with age in emmetropic children, albeit scarce, are valuable on that score. 2 , 3 More recently, Chen et al 4 and Rozema 5 employed meta‐regression to pool normative ocular biometric data from predominantly cross‐sectional studies, further adding to the growing body of knowledge on normal eye growth.…”

Accurate Biometric Palm Print Recognition Using ResNet50 algorithm Over X Gradient Boosting Algorithm

“…Therefore, "physiological" and/or "behavioral" are the two main types of biometrics (Nanni and Brahnam 2021) The physiological category encompasses the physical characteristics of humans, including veins, eyes, hands, and palm prints. The behavioral category comprises a person's movements, including hand gestures, speaking patterns, signatures, etc (Rozema 2023). The assessment of these characteristics aids in biometric system authentication.…”