Juan E. Cedrún-Sánchez

Biometry is a critical aspect of ophthalmology, since it facilitates the measurement of several ocular parameters and aids in the diagnosis of conditions like glaucoma. The advent of the IOLMaster in 1999 marked a pivotal moment in biometry by introducing non-contact and highly precise measurements that revolutionized the field. Low-coherence optical reflectometry devices such as Lenstar LS900 and Aladdin have further advanced biometry, due to the exceptional accuracy they offer. Axial length, a fundamental measurement in biometry, directly correlates with conditions like myopia and glaucoma. The accurate measurement of axial length is crucial for diagnosis and treatment planning. Biometry also guides intraocular lens power calculation during cataract surgery, relying on factors like axial length, anterior chamber depth, lens thickness, and effective lens position (ELP). Ensuring precision in these measurements is essential for optimal surgical outcomes. While several studies have explored biometric parameters, dynamic changes in crystalline lens thickness during rest or accommodation have received little attention. These changes may have a significant effect on the measurement of the anterior chamber length, and consequently impact the overall biometric assessment. This study delves into dynamic biometry, particularly in the context of age-related presbyopia, and aims to assess the feasibility of incorporating into the biometric process a specialized device capable of accurately considering crystalline lens changes during different states like rest and accommodation. This exploration seeks to enhance the understanding of ocular dynamics and contribute to improving the precision of diagnostic and surgical techniques. It underscores the importance of staying at the forefront of biometric research, especially in the context of emerging technologies and their potential to transform ophthalmology.

Purpose To examine relationships between mesopic visual sensitivity measurements on microperimetry and macular inner and outer retinal layer (IRL and ORL) thicknesses in healthy younger, middle‐aged and older subjects. Methods In total, 154 healthy adults were divided into three age groups each with similar mean sensitivity. Regional retinal sensitivity (determined by mesopic fundus‐controlled microperimetry) and IRL (ganglion cell‐related layer) and ORL thicknesses were measured in the five subfields: central fovea (1 mm diameter) and the quadrants temporal, nasal, superior and inferior of a parafoveal ring of outer diameter 3 mm and inner diameter 1 mm. Relationships between regional sensitivity and corresponding IRL and ORL thicknesses were assessed through a univariate and multivariate linear regression model. Results Visual sensitivity means for each subfield differed across age groups (all p < 0.001). In each parafoveal ring quadrant, mean IRL thickness was reduced in the older eyes compared to the other groups (all p < 0.0001). In the inferior region, worse sensitivity was correlated with greater IRL thickness ( p = 0.0207) in the middle‐aged group and with a thicker ORL ( p < 0.0001) and thinner IRL ( p = 0.0003) in the older eyes ( R 2 = 0.51). The slopes of regression lines relating sensitivity to IRL thickness and age group ( p = 0.0027) or to ORL thickness and age group ( p = 0.0020) differed significantly. Conclusions The relationship observed between mesopic visual sensitivity and retinal layer thickness varied with age. A worse sensitivity was related to a thicker macular IRL layer in middle‐aged eyes and to a thicker ORL and thinner IRL in older eyes.