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Biometry before primary surgery: In cases of combined phaco/IOL and silicone oil removal, it is difficult to obtain a good axial length measurement with silicone oil in situ. If there is a high chance of using silicone oil as a tamponade in a phakic eye, we recommend performing biometry before the primary surgery. Some units routinely perform biometry on all phakic patients undergoing vitrectomy to be prepared if an unforeseen phaco/IOL has to be performed during the initial vitrectomy or for cases where silicone oil is used as a tamponade. If no biometry is available, best results are obtained with the IOL-Master (Zeiss, Germany). Alternatively, if the preoperative refraction is known and both eyes had a fairly similar preoperative refraction, we use the corneal measurements of the eye filled with silicone oil and the axial length of the other eye to calculate the IOL power.
5.2Vitreous Haemorrhage
DVD
Video 6 Vitreous bleeding of unknown aetiology
A vitreous haemorrhage with attached retina and no associated major vitreoretinal pathology is suitable for the beginner. He/she learns to work with the vitreous cutter and apply a PRP, but does not need to perform any significant manipulations of the retina. This surgery can be performed under local anaesthesia. In the learning phase, the beginner will often perform a PPV with vitreous haemorrhage. The main problem with this procedure is that you have no view into the retina. The procedure is even more difficult when the natural lens is still present due to the risk of injuring the posterior capsule. In the learning phase, perform only PPVs in pseudophakic eyes.
Pits & Pearls
B-scan: In cases with vitreous haemorrhage, always perform a detailed preoperative ultrasound examination yourself. Try to determine the state of the posterior vitreous face (attached, partially attached or detached) and the retina. Search for areas of focal vitreoretinal adhesion and traction (retinal breaks, proliferative retinopathy) and, finally, try to identify possible tumours or choroidal detachments. This is also important for the planning of the position of your trocars. Try to view the retina with indirect ophthalmoscopy in all cases of vitreous haemorrhage. You will sometimes find a gap and be able to see the retina. This may provide valuable information regarding the underlying disease and its treatment.
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Pits & Pearls
Do not underestimate the difficulty of the procedure, even in ‘straightforward’ cases. For example, proliferative retinopathy secondary to retinal vein occlusions or Terson syndrome may be associated with very strong vitreoretinal adhesions that can be difficult to dissect. Simple pulling and lifting with the vitreous cutter may lead to extensive retinal damage.
Pits & Pearls
Examine the retrolental vitreous carefully at the slit lamp. In cases of dense vitreous haemorrhage, this may also be cloudy and will need to be removed to enable a good intraoperative view. In phakic patients, this can sometimes be difficult without touching the lens. Prepare everything in advance so a combined phaco/IOL can be performed if needed.
Instruments
1.3-port trocar
2.120D lens
3.Vitreous cutter
4.Fluid needle
5.Scleral depressor
Tamponade
Air, SF6
Individual steps
1.3-port system
2.Core vitrectomy
3.Posterior vitreous detachment and peripheral vitrectomy
4.Tamponade
5.Removal of the trocar cannulas
1.3-port system
2.3-port vitrectomy system and core vitrectomy
Vitreous haemorrhage may be caused by several diseases such as diabetes, vein occlusion or haemorrhagic AMD. In many cases, a PVD is present, and the haemorrhage
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Fig. 5.10 PPV for vitreous haemorrhage and posterior vitreous detachment. If you cut a hole in the posterior hyaloid, you will gain a view onto the retina
fills out the vitreous gel behind the lens. However, a partial PVD with focal vitreoretinal adhesions, in particular in the area of retinal proliferations, is also fairly commonly seen.
This vitreous haemorrhage reduces the illumination of the light fiber because the light cone is hidden by blood. Therefore, you should first make a core vitrectomy. Keep the first vitreous cutter behind the lens and remove all vitreous gel. It might be easier to work first without BIOM and use the microscope only as you would in cataract surgery. If the view is not improved, then try only to aspirate the liquefied blood. Then try to cut a break in the posterior hyaloid in order to view the retina (Fig. 5.10). It is important to identify the retinal vessels to make sure that you are in the right plane (and not in the subretinal space). If you succeed, continue the vitrectomy from the break in the posterior hyaloid.
You then proceed to trim the vitreous base. Do not trim the vitreous base completely because the risk of causing damage to the retina is higher than the benefits. You should, however, try to find the cause of the haemorrhage and treat it (laser, endodiathermy or cryo). If you do not find a central bleeding source, then search in the periphery.
Pits & Pearls
The haemorrhagic vitreous blocks/clogs sometimes the infusion. Check the infusion trocar before vitrectomy, and if in doubt, cut the haemorrhagic vitreous around the infusion trocar.
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Pits & Pearls No. 38
Removal of anterior hyaloid: In case of a haemorrhage directly behind the lens, it is may be necessary to remove the anterior hyaloid (see Fig. 4.8). This is an easy procedure in pseudophakic patients but a lens threatening procedure in phakic patients. We perform two techniques: Work at the edge of the lens (i.e. behind the zonules) in order to avoid a lens touch. (1) With help of a serrated jaws forceps, grab the anterior hyaloid/vitreous and pull it towards the centre of the globe. Work from both sides. (2) With help of a vitreous cutter, suck the anterior hyaloid/vitreous (only aspiration) and pull the vitreous cutter towards the centre of the globe. Cut the vitreous there. Work from both sides.
3. Posterior vitreous detachment and peripheral vitrectomy
If the posterior vitreous face is not detached, then a PVD should be performed now. If the aetiology of the haemorrhage is, for example a bleeding vessel, treat it now with laser, diathermy or cryo. Beware of focal vitreoretinal adhesions, in particular in the area of retinal proliferations in proliferative diabetic retinopathy or retinal vein occlusions. By simply pulling on them to complete the PVD, you may cause significant retinal damage and breaks. It takes some experience to judge if an epiretinal proliferation can be just ‘peeled off’ or if it needs to be dissected with cutter and/or scissors. In the case of doubt, stop pulling and start cutting.
Pits & Pearls No. 39
How to remove epiretinal blood. (1) Aspirate the blood with a fluid needle. (2) By pressing several times on the side opening/tubing of the fluid needle, water is ejected from the fluid tip and blows up the epiretinal blood. The blood can then be easily aspirated. (3) Clotted blood can be grasped with the Eckardt forceps and be removed with the vitreous cutter.
4. Tamponade
An air or gas tamponade is recommended to avoid a re-bleeding into the vitreous cavity. In cases of proliferative retinal disease, it is advisable to perform retinal photocoagulation intraoperatively. It is the best opportunity to do so, as in many cases, a minor postoperative re-bleeding will prevent a good view and a sufficient laser treatment. Some surgeons also use a bevacizumab injection at the end of the procedure to lower the rate of re-bleeding. However, there is no consensus on the advantages or disadvantages of this adjunct.