Analysis of Microvasculature in Nonhuman Primate Macula With Acute Elevated Intraocular Pressure Using Optical Coherence Tomography Angiography

Abstract Background:Although the pathogenesis of glaucoma is not fully understood ,an elevated intraocular pressure (IOP) is a major factor contributing to its development and progression. The aim of this study was to investigate the changes in the retinal blood flows of the macula and optic nerve head (ONH) after an acute elevation in the intraocular pressure (IOP) observed using optical coherence tomography angiography (OCTA). Methods: This was a prospective comparative study of subjects with narrow anterior chamber angles who underwent laser peripheral iridotomies (LPIs). The IOP was measured before and one hour after the LPI. The retinal blood flows of the macula and ONH were measured using OCTA at the baseline and one hour after the LPI. Results: A total of 64 eyes of 51 individuals were enrolled in this study, and 58 eyes of 43 individuals finally completed the study with a mean IOP rise of 10.5 ± 7.6 mmHg after the LPI. Based on the magnitude of the rise in the IOP, we divided the subjects into three groups: group A = IOP rise ≤ 10 mmHg, group B = 10 mmHg < IOP rise ≤ 20 mmHg, and group C = IOP rise > 20 mmHg. The vessel density did not differ after the acute IOP elevation in either the macular region or papillary region in group A or group B (p > 0.05), but there was a significant difference in group C (p < 0.05). However, when the subjects were not separated into groups, the vessel densities of the ONH and macular region did not differ between the measurements obtained at the baseline and one hour after the LPI (p>0.05). Conclusion: In these normal subjects, an acute mild or moderate IOP elevation for one hour after the LPI did not affect the blood flow in the macula or ONH, as examined using OCTA. However, when the IOP rise was greater than 20 mmHg, the macular and papillary blood flows decreased significantly.

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Optical coherence tomography in the evaluation of structural changes in primary open-angle glaucoma with and without elevated intraocular pressure

Vojnosanitetski pregled ◽

10.2298/vsp150218068t ◽

2016 ◽

Vol 73 (7) ◽

pp. 618-625

Author(s):

Marija Trenkic-Bozinovic ◽

Gordana Zlatanovic ◽

Predrag Jovanovic ◽

Dragan Veselinovic ◽

Jasmina Djordjevic-Jocic ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Intraocular Pressure ◽

Primary Open Angle Glaucoma ◽

Open Angle Glaucoma ◽

Optical Coherence ◽

Open Angle ◽

Significant Information ◽

Rnfl Thickness ◽

Significant Difference ◽

Elevated Intraocular Pressure

Background/Aim. Glaucoma is a progressive optic neuropathy characterized by damage of the retinal ganglion cells and their axons and glial cells. The aim of this study was to evaluate the differences and connections between changes in the visual field and the thickness of the peripapillary retinal nerve fiber layer (RNFL), using optical coherence tomography (OCT) in patients with primary open-angle glaucoma with normal and elevated intraocular pressure (IOP). Methods. This prospective study included 38 patients (38 eyes) with primary open-angle glaucoma with normal intraocular pressure (NTG) and 50 patients (50 eyes) with primary open-angle glaucoma with elevated intraocular pressure (HTG), paired by the same degree of structural glaucomatous changes in the optic nerve head and by age. OCT protocols ?fast RNFL thickness? and ?fast optic disc? were used for testing. The patients? age, gender, best corrected visual acuity (BCVA), IOP, stereometric and functional parameters were compared. Results. The average age of the examined population was 65.49 ? 9.36 (range 44-83) years. There was no statistically significant difference by age and by gender between the two study groups (p = 0.795 and p = 0.807, respectively). BCVA was higher in patients with NTG but there was no statistically significant difference compared to HTG patients (p = 0.160). IOP was statistically significantly higher in patients with HTG compared to NTG patients (17.40 ? 2.77 mmHg vs 14.95 ? 3.01 mmHg, p = 0.009). The cup/disc (C/D) (p = 0.258), mean deviation (MD) (p = 0.477), corrected patern standard deviation (CPSD) (p = 0.943), disk area (p = 0.515), rim area (p = 0.294), rim volume (p = 0.118), C/D area R (p = 0.103), RNFL Average (p = 0.632), RNFL Superior (p = 0.283) and RNFL Inferior (p = 0.488) were not statistically significantly different between the groups. Conclusion. OCT measurements of the RNFL thickness provide clinically significant information in monitoring of glaucomatous changes. There are no differences in the patterns of RNFL defects per sectors and quadrants between NTG and HTG, measured by OCT.

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