Classification of Diabetic Tractional Retinal Detachment
I need to clarify that the question asks about "diabetic fractional retinal detachment," but the correct terminology is "diabetic tractional retinal detachment" (TRD), which is a well-recognized complication of proliferative diabetic retinopathy.
Primary Classification System
Diabetic tractional retinal detachment is classified into three main categories based on the mechanism and presence of retinal breaks: pure tractional retinal detachment (TRD), combined tractional and rhegmatogenous retinal detachment (CTRRD), and tractional retinoschisis. 1, 2
1. Pure Tractional Retinal Detachment (TRD)
TRD occurs when fibrovascular proliferation from proliferative diabetic retinopathy creates anteroposterior traction on the retina without any retinal breaks. 3, 2
The retinal elevation maintains a concave contour and does not extend to the ora serrata, even if retinal holes subsequently develop. 3
This represents the most common form of diabetic retinal detachment and is a direct complication of advanced proliferative diabetic retinopathy (PDR). 4, 2
2. Combined Tractional and Rhegmatogenous Retinal Detachment (CTRRD)
CTRRD occurs when tractional forces create retinal breaks, allowing vitreous fluid to enter the subretinal space, combining both tractional and rhegmatogenous mechanisms. 1, 2
This diagnosis is confirmed when pigment lines are present or when the retinal elevation rapidly becomes convex and extends to the ora serrata after a retinal hole develops. 3
Risk factors for developing CTRRD include: extensive tractional retinal detachment involving 3-4 quadrants (59.6% of cases), broad adhesion of fibrovascular proliferation at ≥3 sites (66.7% of cases), and extensive preretinal fibrosis. 1, 5
Recent panretinal photocoagulation (PRP) or intravitreal anti-VEGF therapy within 3 months may provoke combined retinal detachment, likely due to rapid contraction of fibrovascular tissue. 1
3. Tractional Retinoschisis
Tractional retinoschisis represents splitting of the retinal layers due to tangential traction, maintaining a concave contour even after retinal holes develop. 3
This can be distinguished from true retinal detachment by the persistent concave configuration and lack of rapid progression to the ora serrata. 3
In a series of 200 eyes with tractional elevations, 39 eyes (19.5%) had unequivocal tractional retinoschisis, while 65 eyes (32.5%) had definite tractional retinal detachment. 3
Clinical Classification by Severity
Based on Extent and Activity
Extent of detachment: Classified by number of quadrants involved, with 3-4 quadrant involvement associated with worse visual outcomes. 1
Activity of fibrovascular proliferation: Active FVP (present in 57.9% of cases) versus inactive fibrosis influences surgical planning and prognosis. 1
Macular involvement: Whether the fovea is detached significantly impacts visual prognosis and urgency of intervention. 2
Surgical Indications Classification
Current indications for pars plana vitrectomy in diabetic retinal detachment include: TRD threatening or involving the macula, CTRRD, persistent vitreous hemorrhage obscuring TRD, and progressive TRD despite adequate panretinal photocoagulation. 2
Important Clinical Pitfalls
Do not confuse tractional retinoschisis with tractional retinal detachment—the former maintains concave contour and has better prognosis, while the latter may progress rapidly, especially if breaks develop. 3
Be aware that recent PRP or anti-VEGF therapy can precipitate acute tractional detachment through rapid contraction of fibrovascular tissue, so close monitoring is essential in the first 3 months post-treatment. 1
Large tractional detachments (≥3 quadrants) and extensive preretinal fibrosis are significant risk factors for retinal break formation, converting pure TRD to more complex CTRRD. 5
Poor preoperative visual acuity, severe vitreoretinal adhesion, and broad extent of retinal detachment predict poor visual outcomes even with successful anatomical reattachment (93% primary success rate). 1