Effects of myopia-associated factors and aging on visual field (VF) subfield sensitivities in normal eyes

Abstract

Purpose :
Knowledge of the effects of non-pathological factors on VF sensitivity in normal eyes is a prerequisite in diagnosing eyes with pathology. Two non-pathological factors, myopia-associated factors and aging, are known to affect VF sensitivity in normal eyes, but our knowledge of how these two affect it is not detailed enough. We studied the effects of these 2 factors in a cross-sectional group (C) and longitudinal group (L) of normal subjects.

Methods : The C included 1022 eyes of 539 subjects (mean age=52.7 yr.) that were confirmed to be normal without clinically significant cataract with refractive error ≤ +3 and ≥ -6 diopters, axial length (AL) ≤ 26 mm, BCVA ≥1.0, reliable HFA 24-2 SITA-S (HFA 24-2) results with FL ≤ 20% and FP ≤ 15%, and acceptable fundus planimetric results. The C was divided into the younger and older C at an age of 53 yrs. The L included 109 eyes of 59 normal subjects (mean age=52.3 yrs.) who satisfied the above criteria and were followed at intervals of 3 - 6 months without developing any ocular abnormalities. HFA 24-2 VF was divided into the fovea, central VF (VF_c) including ceco-central 6 points and peripheral VF (VF_p) excluding VF_c and nasal 4 points. The mean sensitivity in each subfield in the C or its time change in the L was analyzed with linear mixed modeled regression analysis using age, rim area, AL, β-peripapillary atrophy area (β-PPA) and disc ovality and torsion angle as co-variables.

Results : In the older C, age showed negative impact on the mean sensitivity in all subfields (-0.12 ± 0.01 (SE) ~ -0.11 ± 0.02 dB/yr., P<0.001) with no significant inter-subfield differences. Besides age, β-PPA showed negative impact (-0.20 ± 0.09 dB/mm², P=0.029) only in the VF_c. In the L, duration showed negative impact in all subfields (-0.009 ± 0.002 ~ -0.007 ± 0.001 dB/yr., P<0.001) with no significant inter-subfield differences. Interaction of duration with age was significant (P<0.001) in all subfields, but that with β-PPA only in the VF_p (P=0.016).

Conclusions :
Aging-related VF sensitivity reduction was accelerated independent of the eccentricity. Besides age, only β-PPA had significantly negative impact on the central VF sensitivity, but its effect on the aging-related VF sensitivity reduction was more evident in the peripheral VF.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.