Abstract
Purpose :
Quantify accommodative movements of intravitreal structures/fluid in the monkey eye to determine if they are related to accommodative amplitude and presbyopia.
Methods :
In eyes of 11 rhesus monkeys (aged 8-22 yrs), maximum accommodative responses were induced by central electrical stimulation of the Edinger-Westphal (E-W) nucleus. Ultrasound biomicroscopy (UBM; 50, 20 MHz) images were collected in the region of the lens, ciliary body and over the entire extent of the globe.
Results :
During accommodation, the anterior hyaloid bowed backward by 0.26 ± 0.02 mm [mean ± s.e.m.] (p= 0.001; n=8), the central vitreous moved posteriorly by 0.27 ± 0.05 mm (p= 0.001; n=7), while the peripheral lacunae (cistern) tips move forward by 0.42 ± 0.09 mm (p= 0.002; n=8), and inward (centripetally) by 0.14 ± 0.02 mm (p= 0.001; n=8). Accommodative central vitreous posterior movement was significantly related to accommodative amplitude; the more the central vitreous moved posteriorly during accommodation, the higher the accommodative amplitude (32.9 ± 9.64 diopters/mm; p= 0.019; n=7), and these movements declined significantly with increasing age (-0.0185 ± 0.0062 mm/yr; p= 0.031; n=7). In addition, the accommodative forward movement of the peripheral lacunae (cistern) tips increased with increasing accommodative amplitude; the greater the forward movement of the cistern tip the higher the accommodative amplitude (16.95 ± 6.52 D/mm; p = 0.047; n=8) and these movements tended to decline with age (-0.024 ± 0.011 mm/yr; p = 0.08; p=8). Accommodative backward bowing of the anterior hyaloid and centripetal movement of the cistern tip were not significantly related to accommodative amplitude and did not decline significantly with age.
Conclusions :
There are statistically significant accommodative movements of various intravitreal structures. The posterior central vitreous movement and the forward movement of the cistern tip are related to accommodative amplitude and decline with age, and may be related to the mechanism of accommodation, presbyopia and perhaps glaucoma. These findings may also inform on the mechanism of accommodation and presbyopia, and the function of accommodating IOLs.
This is a 2021 ARVO Annual Meeting abstract.