Fig. 10.7 Same procedure as Fig. 10.4. The ‘left hand’ injects PFCL, and the ‘right hand’ drains subretinal fluid from the break

covering all retinal breaks. Then switch to air/fluid exchange and remove the air from the retrolental space with the fluid needle. If everything has been performed correctly, you should now have a fully reattached retina without any subretinal fluid and a complete PFCL fill. The photocoagulation can now be performed with a completely attached break (Fig. 10.7).

Pits & Pearls No. 53

Retinotomy: In case of a highly bullous inferior detachment with a superior break or a posterior location of the break, there is much trapped fluid anterior to the PFCL bubble. In the first case, one can try to massage the subretinal fluid with a scleral depressor to the break. Or perform a retinotomy in the area of trapped fluid. Mark the inferior retina close to the ora serrata with endodiathermy. Then cut a hole with the vitreous cutter (setting: approx. 300 cuts/ min) by suctioning the retina and then cutting it cautiously. Drain the subretinal fluid from this break.

8. Laser therapy of breaks

Apply three rows of laser burns around the breaks (Fig. 10.8). The settings depend on the laser device.

It is possible that subretinal fluid has accumulated now anterior to the break (socalled trapped fluid) which makes it difficult to apply a laser onto the anterior part of the break. Try to indent the break with the scleral depressor so that the subretinal fluid is pushed away. Apply white laser burns. A good alternative is to freeze the break with a cryoprobe. If you do not succeed due to excess trapped fluid, then complete the laser treatment in a later step (see step 10). But before we do this, we need to remove the vitreous base and implant an IOL.

Fig. 10.8 Three rows of laser burns are applied around the break, which was marked with endodiathermy. Next to the break you recognize an old cryoscar

Pits & Pearls

Laser: Be careful with your laser energy. Only a mild whitening of the RPE is necessary. Burns which are too strong will weaken the retina and are a predilection site for the formation of new retinal breaks. They may also cause contraction of the choroid or even choroidal haemorrhages. A typical beginner’s mistake is to perform too much laser or cryotherapy as an extra safety measure that then may turn out to have exactly the opposite effect.

Pits & Pearls

Laser cerclage: A circumferential 360° laser is not recommended. It is essential to identify and treat all retinal breaks. A circumferential laser has the big disadvantage that in case of a re-detachment, the breaks are difficult to find within the patches of chorioretinal atrophy.

9. Vitrectomy of vitreous base (shaving)

If it has not been performed before, drainage of all subretinal fluid should be carried out (see above), and a thorough vitrectomy of the vitreous base has to be performed at this stage using the scleral depressor. This procedure is also called ‘shaving’. PFCL lifts the vitreous up and enables a secure and thorough trimming of the vitreous base. In those areas, where PFCL does not rest on the retina, there is vitreous which has to be removed (Figs. 10.9 and 10.10). Indent the sclera and move the vitreous cutter along the meniscus of the PFCL. Hereby you can manoeuvre the vitreous cutter very close to the retina because the heavy liquid presses against the retina.

Fig. 10.9 Situation before shaving. PFCL is injected up to the ora serrata. The transparent space between retina and PFCL is filled with vitreous

Fig. 10.10 Situation after shaving. The vitreous and henceforth the transparent space have been removed with the vitreous cutter

10. Implantation of the IOL

If the IOL has not already been implanted, you have to do it now in a PFCL-filled eye. During the implantation of the IOL, the infusion is switched off. You then have to decide whether to use gas or silicone oil tamponade. If you want to use gas, continue at step 12. If you want to use silicone oil, you have to decide whether you want to do first a PFCL/air exchange and then perform an air/silicone oil exchange (go to step 12) or whether you want to perform direct PFCL/silicone oil exchange (go to step 11).

11. PFCL to silicone oil exchange

Prepare the anterior chamber before performing a heavy liquid to silicone oil exchange; stabilize the anterior chamber and perform an Ando iridectomy or inject methylcellulose if necessary.

Pits & Pearl No. 54

Ando iridectomy: If aphakia or zonular lysis is present, create an Ando iridectomy (6 o’clock) to prevent an increase in intraocular pressure. An Ando iridectomy prevents a silicone oil prolapse into the anterior chamber and a secondary angle-closure, because the aqueous can flow through the iridectomy at 6 o’clock into the anterior chamber and press the oil bubble back into the vitreous cavity.

Pits & Pearls

Methylcellulose in anterior chamber: If a large zonular lysis is present, inject now methylcellulose into the anterior chamber; it can be left there postoperatively. It holds the anterior chamber free of silicone oil. There will be only a slight postoperative rise in IOP.

Diagram 10.2 Diagram of the location of the fluids in the vitreous cavity

Diagram 10.2 shows the location of the fluids in the vitreous cavity. Silicone oil is lighter than water. Intraoperatively perfluorocarbon is the heaviest liquid and lies always on the posterior pole. Anterior to perfluorocarbon is water, and anterior to that is silicone oil. Postoperatively, the perfluorocarbon is removed, and therefore, water is located at the bottom and silicone oil at the top.

When replacing PFCL with silicone oil, the silicone oil-filled syringe is connected to the vitrectomy machine and the active-injection mode activated. The silicone oil is injected in the eye, while you hold the fluid tip in the PFCL phase and aspirate the PFCL (Fig. 4.11a, b). At the end of the aspiration, you recognize clearly the PFCL meniscus and also the final PFCL-puddle at the posterior pole. Pay attention to a positive venous pulse. In an emergency of high intraocular pressure, pull off a valve so that excess oil can flow out.

If subretinal fluid is present, remove it by holding the tip of the fluid needle in the break. Aspirate the subretinal fluid under the pressure of the incoming oil and increase the pressure in the eye by injecting more oil. If the break is fully attached, you can complete the photocoagulation.