What is Parapapillary atrophy?
Peripapillary atrophy (PPA) is a clinical finding associated with chorioretinal thinning and disruption of the retinal pigment epithelium (RPE) in the area surrounding the optic disc. It is non-specific and can occur in both benign and pathologic conditions, including glaucoma 1 and high myopia 2.
What is beta zone peripapillary atrophy?
β-zone PPA was defined as an area adjacent to the disc margin with notable atrophy of the retinal pigment epithelium, visible sclera, and visible large choroidal vessels. In cases where baseline stereophotographs did not show βPPA, progression was defined as development of βPPA that was not present at baseline.
What is beta atrophy?
Beta peripapillary chorioretinal atrophy (beta-PPA) is defined as an area of visible sclera adjacent to the clinically visible optic disc margin,1 corresponding to an area without RPE.
What is the Gamma zone?
As “gamma zone”, we defined the region between the outer margin of the optic nerve (covered by pia mater) and the end of Bruch’s membrane, if the end of Bruch’s membrane did not overhang into the region of the optic nerve head (Fig. 1).
Can Peripapillary atrophy cause visual field defects?
Another study found a strong correlation between the progression of PPA, visual field loss and thinning of the neuroretinal rim. Earlier studies also showed that as PPA progresses, so too does glaucomatous damage.
How does high myopia cause glaucoma?
High myopia can be associated with elongation of the eye and resultant tilting and torsion of the optic nerve head, causing visual field defects that may resem-ble glaucomatous damage, but are the result of myopia. This can make an accurate glaucoma diagnosis challenging, since there’s no bio-marker for disease.
What is beta zone?
The beta zone, defined by the presence of Bruch’s membrane and absence of RPE, was a whitish zone upon ophthalmoscopy and showed large choroidal vessels and the sclera. It was located at the inner border of the alpha zone in the same direction as the optic disc.
What is the alpha and beta zone?
The alpha zone was defined as irregular hyperpigmentation and hypopigmentation and it was located in the periphery of the parapapillary atrophy. The beta zone was characterized by visible sclera and visible large choroidal vessels and location between the peripapillary scleral ring and alpha zone.
Is Peripapillary atrophy common?
Chorioretinal atrophy surrounding the optic disc (known as either peri- or parapapillary atrophy) is a relatively common clinical finding.
Does myopia affect optic nerve?
The association between myopia and POAG has been thought to be due to a variety of mechanisms, including increased susceptibility of the optic nerve head to damage by raised IOP and the increased effect of shearing forces in optic nerve head damage.
What is parapapillary atrophy?
Parapapillary atrophy: histological gamma zone and delta zone Parapapillary gamma zone (peripapillary sclera without overlying choroid, Bruch’s membrane and deep retinal layers) was related with axial globe elongation and was independent of glaucoma.
Is beta-zone parapapillary atrophy more common in eyes with glaucoma?
Purpose: Beta-Zone parapapillary atrophy (PPA) occurs more commonly in eyes with glaucoma. Rates of glaucomatous visual field (VF) progression in eyes with and without beta-zone PPA at the time of baseline assessment were compared. Design: Retrospective, comparative study.
What is the delta zone in parapapillary sclera?
Parapapillary gamma zone (peripapillary sclera without overlying choroid, Bruch’s membrane and deep retinal layers) was related with axial globe elongation and was independent of glaucoma. Delta zone (no blood vessels >50 µm diameter within gamma zone) was present only in highly axially elongated …
What is the beta zone in glaucoma?
“Delta zone” was defined as part of gamma zone in which blood vessels of at least 50 µm diameter were not present over a length of >300 µm. Beta zone (mean length:0.35±0.52 mm) was significantly (P = 0.01) larger in the glaucoma group than in the non-glaucomatous group.