PARAVASCULAR INNER RETINAL DEFECTS (PIRDs) IN GLAUCOMA

 

Paravascular inner retinal defects (PIRDs) are spindle-shaped or caterpillar-shaped dark areas along the major retinal vessels. These lesions have been reported in eyes with high myopia and epiretinal membranes (ERM) previously. However, some recent studies have found an association of PIRDs with glaucoma and glaucoma-suspects. Results of these studies argue for glaucomatous damage as a factor that can cause PIRDs independently of ERM and/or myopia.

Muraoka termed this condition PIRD as it did not appear to be a simple cleavage of the inner retina and was often accompanied by a functional abnormality.

In contrast to nerve fiber layer defects associated with glaucoma, most PIRDs have irregular margins, and the widths are variable. The PIRDs are more frequently paravenous than para-arterial. They appear disconnected from the optic disc on ophthalmoscopy.

On red-free images, PIRDs appear as high-contrast retinal rarefactions.

These lesions are most frequently detected in the superior hemisphere and temporal area of the optic disc (Supero-temporally).

Goldmann perimetry often shows a visual field defect corresponding to the lesion. In Muraoka’s study the most common associated visual field defects were relative Bjerrum scotoma (in 75% [60 of 80]; 95% CI, 66%-85%) and nasal steps (in 59% [47 of 80]; 95% CI, 48%-70%).

On OCT scans, the PIRDs appear as cystoid or fissure like wide defects in the inner retina or underneath the major retinal vessels, often deviating into the vitreous cavity.

Sequential OCT examinations of the retinal vessels has shown that the lesions are remarkably widespread, and a broad defect in the paravascular inner retinal tissue is frequently observed.

REFERENCES:

Muraoka Y, Tsujikawa A, Hata M, et al. Paravascular Inner Retinal Defect Associated With High Myopia or Epiretinal Membrane. JAMA Ophthalmol. 2015;133(4):413–420. doi:10.1001/jamaophthalmol.2014.5632

https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2089676

Donald C. Hood, Nicole De Cuir, Maria A. Mavrommatis, Daiyan Xin, Hassan Muhammad, Juan Reynaud, Robert Ritch, Brad Fortune; Defects Along Blood Vessels in Glaucoma Suspects and Patients. Invest. Ophthalmol. Vis. Sci. 2016;57(4):1680-1686. https://doi.org/10.1167/iovs.15-18499.

https://iovs.arvojournals.org/article.aspx?articleid=2513120