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சுருக்கம்

A Comparison of Retinal Microvascular Density using OCTA in Primary Angle Closure Suspects, Primary Angle Closure Glaucoma, Pseudo Exfoliation Glaucoma and Healthy Controls

Keyvan Shahraki , Zahra Moravvej, Kourosh Shahraki, Mehdi Khodaparast, Ali Makateb, Kianoush Shahraki*

Background: Glaucoma results in a progressive optic neuropathy characterized by degeneration of Retinal Ganglion Cells (RGC) and their axons. The most recent technique for examining vascular changes in the nerve endings is Optical Coherence Tomography Angiography (OCT-A). OCT-A is a noninvasive imaging technique that uses en-face reconstruction of OCT combined with motion contrast to visualize retinal and ONH microvasculature. The spectrum for primary angle closure disease manifest from Primary Angle Closure Suspect (PACS), and Primary Angle Closure (PAC) to PACG. Pseudoexfoliative Glaucoma (PEXG) is rapid progressive open angle glaucoma with high baseline IOP and wide IOP fluctuation compared to other types of Primary Open Angle Glaucoma (POAG). The vascular function relationship between PACG and POAG is different. In the present study we aimed to evaluate the RPC using OCT-A in primary angle closure suspects vs primary angle closure glaucoma vs PEX glaucoma and to compare the results with normal healthy eyes and to investigate correlations between ONH and retinal vessel density measurements to other structural parameters like RNFL thickness.

Methods: Ultrasonographic pachymetry (CCT), RNFL-OCT, Ganglion Cell Complex (GCC) and OCTA of the microvasculature in the optic nerve head and macula was performed in all patients. The study was conducted on four groups of patients: Primary Angle Closure Suspects (PACS), Primary Angle Closure Glaucoma (PACG), PEXG and normal healthy eyes.

Result: The study population consisted of 24 (10 men and 14 women) primary angle closure suspect eyes (Group A), 25 (13 men and 12 women) primary angle closure glaucoma eyes (Group B), 20 (12 men and 8 women) PEX glaucoma eyes (Group C) and 30 (19 men and 11 women) healthy eyes for control (Group D). The NFL thickness values in all sectors were significantly lower in Groups B and C compared with the normal control eyes in Group D, except for the Superior Temporal (ST) and the Inferior Temporal (IT) sectors which were only significantly lower in the PACG group (Group B). GCC values in the PACG (Group B) were thinner than the PACS (Group A) and control group (Group D). VD in group B and C were significantly lower than those in the PACS (group A) and healthy eyes groups (group D)

Conclusions: The OCTA vessel density was significantly reduced in PACG and PEXG eyes in all circumpapillary sectors and the macula. The wi-VD and cp-VD perform as well as the RNFL thickness for discriminating between healthy and glaucoma. This noninvasive method of RPC vessel density assessment is reliable for detecting glaucoma similar to OCT RNFL thickness. Also, OCTA could be of use for monitoring decrease in RPC VD before glaucomatous optic neuropathy and structural changes have occurred in PAC and PEX eyes