12.2.3Progression to Vitreous Haemorrhage and Tractional Retinal Detachment

In general, progression to vitreous haemorrhage or retinal detachment can be seen as a sign of failure in the systems of screening to detect diabetic retinopathy early, monitoring and treatment of the retinopathy but also in the care of the patients diabetes, blood pressure and other factors such as serum lipids by the diabetic physician and the patient themselves. The DRS and EDTRS showed reduction in sight loss by 50Ð70 % not elimination of sight loss (The Diabetic Retinopathy Study Research Group 1978; The Diabetic Retinopathy Study Research Group 1981; Early Treatment Diabetic Retinopathy Study Research Group 1991) because these patients develop maculopathy (the commonest cause of reduction in central vision), vitreous haemorrhage and tractional retinal detachment. Rates of progression to vitrectomy are reduced by good control of blood sugar, hypertension and lipids and timely and early PRP which reduced risk of PPV to 2.3 % from 4 % in the EDTRS (Early Treatment Diabetic Retinopathy Study Research Group 1991). Neovascularisation needs scaffold to grow on; therefore, PVD is protective, but most of these patients are too young to have PVD and have had laser therapy which may reduce the chance of PVD due to vitreoretinal adhesion at laser spots. Progression has been calculated as 5 %, requiring PPV over 5 years (Early Treatment Diabetic Retinopathy Study Research Group 1991). The prevalence of PPV in the diabetic population in South London has been estimated as 5 per thousand diabetic patients.

Fig. 12.9 A diabetic eye with NVE (vertical arrow) and central vitreous haemorrhage (horizontal arrow)

Demographics

Baseline demographic information in South London, UK

12.2.3.1 Clinical Features

This is by far the commonest cause of haemorrhage into the vitreous cavity. The haemorrhage can occur into the gel or retrohyaloid space or rarely subretinal space (the last usually in association with tractional retinal detachment). Subretinal haemorrhage is associated with a poor visual outcome (Morse et al. 1997). Severe retrohyaloid haemorrhage may cause the posterior vitreous face to bulge forwards in bullae. Often diabetic haemorrhaging occurs spontaneously, that is, from action of the vitreous on the new blood vessels, but occasionally haemorrhage happens during vigorous isometric exertion. Approximately 50 % of the haemorrhages will clear spontaneously over 3 months. Untreated neovascularisation may progress over this time, risking further haemorrhage, TRD or neovascular glaucoma. Type one diabetics are particularly at risk of further complications if left too long before surgery (The Diabetic Retinopathy Vitrectomy Study Research Group 1985; Early vitrectomy for severe vitreous hemorrhage in diabetic retinopathy. Four-year results of a randomized trial: Diabetic Retinopathy Vitrectomy Study Report 5 1990), and early intervention is recommended. If waiting for clearance, it is important to monitor the intraocular pressure for erythroclastic glaucoma and to perform repeated ultrasound examinations for retinal detachment.

Causes of vitreous haemorrhage:

¥Active NV

¥Inactive NV

¥Vessel avulsion

¥Traction from vitreous

¥Pathological shrinkage

¥Mobility

¥PVD

¥Acutely raised BP

When to do more PRP and when to perform PPV in patients with vitreous haemorrhage

Fig. 12.10 Tractional membranes often follow the vascular arcades

Indicators for early surgical intervention:

B-scan ultrasound examination is important to determine where the blood is situated, whether there is tractional retinal detachment, rhegmatogenous retinal detachment or posterior vitreous detachment, and is accurate in 90 % of cases (Genovesi-Ebert et al. 1998). Adhesion of the vitreous to the retina can be seen at the sites of neovascularisation often on the vascular arcades or at the optic disc. The extent of the vitreoretinal adhesion should be assessed to guide the surgeon on the complexity of the surgery. The role of vitrectomy in the management of the complications of diabetic retinopathy has been established for many years (Mandelcorn et al. 1976; Michels 1978; Aaberg 1979). The success rates of PPV are now high enough to offer surgery early in the clinical course of the haemorrhage without waiting for spontaneous clearance of the bleed.

In some circumstances, if the vitreous haemorrhage is mild, further laser can be applied to try to regress the neovascularisation without PPV. Some patients will bleed despite extensive PRP because of the presence of established neovascularisation which although gliosed has the capacity to bleed because of movement of attached gel or because the patient has an avulsed retinal blood vessel. These patients will not respond to further laser and will require PPV. The role of anti-VEGF injections in the treatment of vitreous haemorrhage has yet to be clariÞed although claims of more rapid regression of haemorrhage with injection alone have been made (Huang et al. 2009).

12.2.3.2 Surgery

Additional surgical steps

Remove the core vitreous and make a perforation in the posterior hyaloid.

Remove any retrohyaloid haemorrhage through the perforation.

Remove the remaining vitreous. Apply panretinal photocoagulation.

Although vitreous haemorrhage from DMR may clear spontaneously after some months, pars plana vitrectomy is frequently required to rehabilitate the patient and can be associated with better visual prognosis (The Diabetic Retinopathy Vitrectomy Study Research Group 1988). The operation is more urgent in young diabetics to prevent irreversible loss of vision (The Diabetic Retinopathy Vitrectomy Study Research Group 1985). Preoperatively it is useful to determine with ultrasound whether the vitreous is fully detached or partially adherent to the retina or whether there is TRD or neovascularisation. A fully detached vitreous indicates an operation, which should be quick with a good prognosis for visual recovery, whereas extensive TRD indicates a longer operation with a poorer prognosis.

If the media are clear, subhyaloid blood can sometimes be treated with YAG laser (Celebi and Kukner 2001; Ulbig et al. 1998) without need for vitrectomy. More often, vitrectomy is required. During surgery, remove the central gel and then make a hole in the posterior hyaloid membrane. Remove the subhyaloid blood by placing a ßute tip in the hole. This allows rapid removal of the subhyaloid blood without allowing it to enter the anterior vitreous cavity to spoil your view. Once the subhyaloid blood is removed, the retina can be identiÞed, and the remaining gel removed with the reassurance that the retina is not detached and at risk of injury from cutter. Peripheral gel should be removed as much as possible as blood will leach out peroperatively and postoperatively, causing vitreous cavity haemorrhage and occasionally erythroclastic glaucoma (raised IOP from clogging of the trabecular meshwork with macrophages laden with red blood cell breakdown products).

Note: When removing blood from the vitreous base, usually, a very thin layer of clear gel at the vitreous base is encountered before hitting the retina.

Panretinal photocoagulation is applied to prevent iris neovascularisation (INV) because the removal of the gel allows easy access of the neovascular factors to the anterior segment, especially in aphakic eyes, increasing the risk of INV (Rice et al. 1983b; Blankenship 1980).

Fig. 12.14 In this patient, excessive neovascularisation is seen superior to the disc in the left eye (see Figs. 12.14Ð12.16). This has caused vitreous haemorrhage requiring PPV. The fellow eye has inactive membranes which have remained stable over a 1-year period with 20/30 vision (see Figs. 12.11Ð12.13)

Fig. 12.15 See previous Þgure

Fig. 12.16 See Fig. 12.14

Fig. 12.17 This patients neovascular membranes are stable 6 years after receiving a pancreatic transplant