Abstract
Purpose :
The aim of this study was to evaluate the changes of morphology of the LC after a reversible experimental intraocular hypertension model in non-human primates and the relationship between IOP and parameters of LC from optical coherence tomography.
Methods :
Ocular hypertension was induced unilaterally by blocking Schlemm's canal with the microcatheter in four cynomolgus monkeys and randomly selected a monkey to remove the microcatheter after the operation of 6 weeks. One of the monkeys was treated sham procedure. The right eye of all the animals were selected as the experimental eyes. The lamina cribrosa depth (LCD), laminar thickness (LCT), lamina cribrosa curvature (LCC) and the width of Bruch's Membrane Opening (BMO) were obtained by enhanced depth imaging (EDI) optical coherence tomography (OCT) biweekly and IOP was measured weekly till the 26 weeks after the operation.
Results :
Except for the sham treatment eye, all of the experimental eyes experienced the sustained intraocular pressure (IOP) elevations. The baseline IOP was 12.5 ± 0.58mmHg and was increased to 48.75 ± 9.43mmHg within 2 weeks and then with the different degrees of reduction. LCD, LCC and the width of BMO achieved the maximum and LCT dived to the minimum almost within 1 month after the peak of IOP. LC deformation returned again followed the decreased of IOP. The maximum fluctuation values of LCD, LCT, LCC and the width of BMO ranged from 79.76 to 167.83um, 21.76 to 38.11um 0.08 to 0.12×10-2um-1 and 26.58 to 49.21um, respectively, among the 4 experimental intraocular hypertension eyes.
Conclusions :
The increase of IOP can lead to the thinning, deepening and posterior bowing of the LC and enlarge the BMO, however, the reduction of IOP within a short period resulted in re-thickening, shallowing and flattening in LC and diminished from the enlarged BMO. All of the young adult monkey eyes with experimental intraocular hypertension reached the baseline level in these parameters mentioned above ultimately. These data suggested that the properties of the LC have excellent compliance and movement. Furthermore, IOP plays an important role in the change of optic nerve head morphology.
This is a 2020 ARVO Annual Meeting abstract.