Optical coherence tomography angiography in glaucoma

Abstract

Assessment of the vasculature within the optic nerve, peripapillary superficial retina, macula, and peripapillary choroid can be determined in glaucoma using optical coherence tomography angiography (OCTA). Decreased perfusion within the pre-laminar layer of the optic nerve has been correlated with glaucoma severity. The peripapillary superficial retinal vessel density allows diagnosis and detection of glaucoma progression in a manner similar to the peripapillary retinal nerve fiber layer (RNFL) thickness.Furthermore, decreased peripapillary vessel density of the intact hemiretina or unaffected eye of glaucomatous eyes suggests that vascular changes can occur prior to detectable visual field damage. The accuracy for glaucoma detection of the macular ganglion cell (MGC) thickness compared to macular vessel density has differed among studies. Several studies have reported reduction of macular vessel density as well as its ganglion cell thickness. Results of studies evaluating the parapapillary choroid have shown a greater prevalence of choroidal microvasculature dropout in glaucomatous eyes with a parapapillary gamma zone,which is associated with central visual field defects or glaucoma progression. It remains unclear whether the reduced vessel density in glaucoma is a primary event or secondary to glaucomatous damage. Further studies are warranted to elucidate this question.

Optical Coherence Tomography-Angiography, a New Diagnostic and Follow-Up Tool for Glaucoma

“…Recent studies support that blood flow disruption can also occur in the deep layers of the retina and choroid, in addition to the superficial layers [55]. A higher frequency of choroidal microvascular dropout (CMvD) in eyes with glaucoma with parapapillary gamma zone has been reported to be associated with glaucoma progression or central visual field defects [56]. Eyes with choroidal microvascular dropout (CMvD) have been shown to be closely associated with the nocturnal diastolic blood pressure drop.…”

Commentary: Can the vessels help solve the puzzle? Distinguishing high myopes from primary open-angle glaucomas

“…It can be evaluated using OCTA in the peripapillary retina, peripapillary choroid, and macula. [ 5 ] Two different vascular plexuses are curently being studied, namely the superficial and deep vascular plexus. Different OCTA devices employ different methods of vessel density measurement.…”

“…Comparison between retinal nerve fiber layer thickness and vascular density have yielded good relatable results. [ 5 ] The role of peripapillary SVD in primary angle-closure glaucoma has also been studied. Vessel densities have shown a significant drop after six weeks following an angle closure attack.…”

Spatial positional relationship between macular superficial vessel density and ganglion cell-inner plexiform layer thickness in primary angle closure glaucoma

“…More than 50% of ganglion cell bodies are located in the macular area, where the thicknesses of ganglion cells are 8–10 layers [ 8 , 9 ]. Ganglion cells are supplied by the macular superficial vascular complex [ 10 ]. Previous studies using OCTA found that macular vessel density decreased and showed fairly diagnostic power in PACG eyes [ 11 , 12 ].…”