The measurement of macular intraretinal layer volume and its influence factors in normal subjects

Background

The histopathological and functional changes are affected by age, gender and axial length (AL). However, whether these factors affect the volume and thickness of various layers of retina is not elucidated.Understanding macular intraretinal layer volume changes and influence factors can offer useful information for relevant clinical study.

Objective

This study was to measure the influence of age, gender and AL on the volume of individual retinal layers at macula zone with optical coherence tomography (OCT) in normal population.

Methods

A cross-sectional study was carried out under the approval of Ethic Committee of Tongling People’s Hospital.One hundred and thirty-four eyes of 92 healthy individuals who received physical examinations and ocular examinations by slit lamp microscope, 90 D pre-set lens, RM-8000A computer automatic optometry and non-contact tomometer were recruited from April to July 2016.The individuals were grouped based on gender or ages (7-14 years group, 15-49 years group, 50-80 years group). The retinal thickness and volume of different layers within 6 mm circle area around fovea were measured by Spectral-OCT with Posterior Pole mode and processed by the layered software.AL was measured with ODM-2100 A/B ultrasonic apparatus.

Results

The volume values of whole retinal thickness (WRL), retinal nerve fiber layer (RNFL), inner nuclear layer (INL) and outer plexiform layer (OPL) in males were (8.80±0.38), (0.92±0.09), (1.03±0.07) and (0.79±0.07)mm³, which were significantly increased in comparison with (8.66±0.34), (0.88±0.07), (1.00±0.07) and (0.77±0.06)mm³in females (P=0.025, 0.027, 0.012, 0.030). The WRL, GCL and IPL volume values were largest in the 15-49 years group and least in the 7-14 years group, and the volume values of RNFL, outer nuclear layer (ONL), retinal pigment epithelium (RPE) and photoreceptors (PC) were significantly lower in the 7-14 years group and 50-80 years group than those in the 15-49 years group (all at P<0.01). The AL was negatively correlated with WRL, GCL and IPL volumes (r=-0.226, -0.385, -0.373, all at P<0.01).

Conclusions

The retinal volume value at macular area is larger in men than that in women.The retinal volume area shows firstly increased and then decreased during aging.The AL shows a negative correlation with the macular volume.