Proliferative Diabetic Retinopathy

SALIENT FEATURES

Any appearance of neovascularization (NV) in an eye with underlying diabetic retinopathy qualifies as proliferative diabetic retinopathy (PDR).
Neovascularization can present as neovascularization of the disc (NVD), neovascularization of the iris (NVI), or neovascularization elsewhere (NVE).
Fibrosis from the scaffold of neovascular vessels growing at the vitreoretinal interface can coalesce into tractional membranes with resultant tractional retinal detachment, combined rhegmatogenous/traction retinal detachment, vitreous hemorrhage, and potentially severe vision loss.
Color and red-free fundus photography and red-free imaging can identify the irregular fine vascular networks extending from the optic disc or retina.
Fluorescein angiography is a useful adjunct imaging modality that can readily identify NV as leakage from irregular vascular networks.
Preretinal hemorrhages and/or vitreous hemorrhage can be seen on fundus photography and is considered a PDR equivalent.

OCT IMAGING

The typical findings of microaneurysms, dot blot hemorrhages, exudates, and cotton wools spots that are seen in NDPR (see Chapter 5) are also seen in PDR. The differentiating feature is the presence of NVD, NVE, or NVI or hemorrhagic equivalent. This is often accompanied by more severe underlying ischemia.

FIGURE 6.1 Optical coherence tomography (OCT) image of a patient with a proliferative diabetic retinopathy with neovascularization of the disc and preretinal tractional membranes. Neovascularization of the disc is evident as a hyperreflective loop extending from the optic disc into the vitreous cavity (white arrow). A broad neovascular tractional membrane is visible temporally as a preretinal hyperreflective sheet (yellow asterisk). Note the continuity of the temporal neovascular membrane with the central epiretinal membrane (yellow arrow). There is traction-induced subretinal (green asterisk) and intraretinal (pink asterisk) fluid present.

Neovascular vessels are seen on optical coherence tomography (OCT) as hyperreflective loops extending from the optic disc or retinal surface that project into the vitreous space and may be adherent to the posterior hyaloid (Figures 6.1 and 6.4).

These may be small foci of hyperreflective protrusions (Figure 6.4, yellow arrow) or larger hyperreflective sheets (Figure 6.1, yellow asterisk).

FIGURE 6.2 (A) Optical coherence tomographies (OCTs) from a patient with preretinal neovascular complexes with adhesion to the posterior hyaloid (yellow arrow). (B) Subhyaloid hemorrhage elsewhere is visible as a homogenous hyperreflective preretinal mass (red asterisk).

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