9.2.4.4 ILM Peel and Other Adjunctive Therapies

Many methods have been described to facilitate macular hole closure. The method favoured here is internal limiting membrane (ILM) peel which can improve success rates from 89 to 94 % (Tognetto et al. 2006; Da Mata et al. 2001; Sheidow et al. 2003). Insert brilliant blue onto the macula to allow staining of the ILM. Leave on the retina for 30 s and remove with a flute. Aim the injection onto the retina just temporal to the macular hole allowing the dye to flow back over the hole. Do not aim at the hole as the dye can enter the subretinal space with potential toxicity to the RPE. This provides a blue stain to the ILM allowing removal. Brilliant blue appears to be less toxic than indocyanine green and is now recommended. During the peel, brilliant blue can be reinjected to help see the edge of the ILM; again inject over undisturbed retina and allow the dye to flow over the macula. The dye can penetrate damaged retina entering the subretinal space if injected with force. Any cut ILM edge will stain more intensely facilitating detection of the ILM.

Note: A previous technique prior to the availability of brilliant blue was to insert indocyanine green dye, 0.5 mg/ml, onto the macula and allow to stain the ILM (Da Mata et al. 2001) briefly (enough time to change the instruments to the aspirating flute needle). Diluting the ICG in 5 % dextrose allows a denser mixture than in BSS; therefore, the dye sits on the macula without dispersing into the vitreous cavity.

Removal with a flute is then rapid and easy. ICG provides a superior stain of the ILM but is less favoured because of toxicity. ICG has been implicated in retinal pigment epithelial toxicity (Engelbrecht et al. 2002; Ho et al. 2003, 2004) resulting in less visual improvement despite improved hole closure (Ando et al. 2004; Gass et al. 2003). The agent has been shown to persist in the eye up to 8 months after insertion (Weinberger et al. 2001; Ciardella et al. 2003). Some have suggested that ICG induces a different cleavage plane for ILM dissection (Haritoglou et al. 2002) which may cause damage to retinal ganglion cells (Horio and Horiguchi 2004). If used, the concentration and duration of application of the dye should be kept to a minimum (Sippy et al. 2001).

If using 20G, make a small slit in the ILM temporal and radial to the fovea with the MVR blade. The slit should be visible now as an orange colour between the two edges of a blue ILM. Using fine forceps, grasp an edge of the ILM and detach the ILM in a circular fashion (similar to performing a capsulorhexis in cataract surgery) around the fovea. Clear at least one disc diameter of ILM from around the fovea. If you are using small gauge, grasp the ILM directly with the forceps to commence the peel.

These manoeuvres can be performed using the IVS; however, if you are experiencing difficulty, place a disposable contact lens onto the cornea (the stereo inverter is disengaged). The contact lens reduced the field of view

Air

Fig. 9.60 Occasionally, the plungers of syringes will stick to the sides of the syringe. The surgeon increases the force on the plunger to make it move and there is a sudden release of the plunger and rapid injection of fluid, e.g. dye. This risks a jet of dye hitting the retina and entering the subretinal space. To overcome this, draw a small amount of air into the syringe; the compressible air cushions the effect of sudden force on the plunger (in effect acting as a damper) preventing a sudden injection of the fluid

considerably but provides better stereopsis. The commencement of the ILM peel is easier because the ILM can be grasped without injury to the underlying nerve fibre layer.

Insert air and exchange with 16 % C3F8 or 20 % C2F6. Silicone oil has been used where gas is undesirable, for example, when air travel is necessary (Goldbaum et al. 1998). This is not recommended routinely because of the need for a second operation for oil removal and the risks of oil-induced complications (Fig. 9.59). Both SF6 and C2F6 have been used for shorter duration of gas but often with more intense posturing.

Fig. 9.61 Inject brilliant blue dye away from the fovea and allow to fall back over the fovea. Injecting directly over the fovea risks insertion of subretinal dye which is potentially toxic (see Figs. 9.62–9.63)

Trypan blue also stains the ILM (and also epiretinal membranes) but less well (Lee et al. 2005). Other agents such as autologous serum (Ezra and Gregor 2004; Banker et al. 1999), autologous platelets (Wachtlin et al. 2003) and transforming growth factor-beta 2 (Lansing et al. 1993; Rosa et al. 1996) have been tried without proven success.

9.2.4.5 Choice of Tamponade

Usually, a long-acting gas bubble is used such as C3F8 or C2F6; shorter duration gas such as SF6 may also be used but may need more rigorous posturing postoperatively. Silicone oil has been inserted (Goldbaum et al. 1998) and heavy oil with face up posture tried with successful closure (Schurmans et al. 2008). Oil use requires further surgery by ROSO which can be avoided by gas insertion. Injection of an expansile gas bubble (0.5 ml of 100 % SF6) can induce a PVD in 95 % with a grade 2 hole closure rate of 50 % in a non-vitrectomised eye (Mori et al. 2007). PPV and air and OCT of a face down patient (face down to allow OCT scan without reflections) has revealed that 54.5 % of holes are closed in 24 h and 75.6 % closed at 40 h postoperatively (Eckardt et al. 2008). In this study, the inner retina closed first followed by the outer retina.

9.2.4.6 Postoperative Posturing of the Patient

It is uncertain whether posturing is necessary to increase the hole closure rate after surgery, but very short-term tamponade agents such as air appear to have reduced success rates of 53 % (Thompson et al. 1994) suggesting that tamponade is important. A randomised controlled study from France has shown that there is a significant increase in success rates for larger holes (grade 3) if a reduced regime of posturing is employed, 8 h a day for 5 days, with overall success rates of 97.5 % if posturing is used and 87.5 % if it is not (Guillaubey et al. 2008). A regime of daytime posturing 50 min in the hour for 3 h in the morning and 3 h in the afternoon for 7 days may be prudent. Posturing compensates for the effects of any operative error in the gas mix which might reduce the bubble size or duration. Posturing face down is easiest with the use of a

specially fabricated frame. Most patients find the posturing particularly bothersome at night, and this can be abandoned.

9.2.4.7 Combined Phacoemulsification and IOL

Cataract is very common after PPV and gas for macular hole. For this reason, cataract surgery is often combined with PPV.

Surgical Pearl of Wisdom

Idiopathic macular hole is a surgical eye condition that can reduce visual acuity severely. It has a high closure rate with improvement of vision in most patients. The standard procedure involves a 3-port pars plana vitrectomy, vitreous removal after induction of posterior vitreous detachment, peeling of any epiretinal membranes and the internal limiting membrane, air–fluid exchange and gas or air tamponade. After surgery, the patient is advised to maintain a 1-week face down head posture in order to optimise the surgical result and facilitate the hole closure.

However, recent studies have shown that hole closure may occur as early as 24 h after surgery in some patients, and in most cases, the hole is closed within 2–3 days after the procedure. Therefore, some authors consider the use of long-acting gas or the 1-week face down head posturing unnecessary for most patients. They advise the use of air or short-acting gas mixture with air in low concentration without head posture or with 1 or 2 days of relaxed positioning. In this way, they claim to achieve results similar to cases treated the traditional way.

I have had three cases of macular hole treated with a standard 23 g 3-port pars plana vitrectomy, vitreous removal, peeling of epiretinal membrane and the internal limiting membrane, air–fluid exchange and 16 % C3F8 gas tamponade. The patients kept the head down for 1 week, and their follow-up was unremarkable until the 1 month visit. At that point, optical coherence tomography showed that the hole was smaller in size but still open in all eyes. All patients still had a considerable amount of gas in their eyes, and, therefore, they were advised to keep their head strictly down for 1 more week. At the end of that week, all holes were closed and remained so thereafter.

It is true that many cases of macular hole will close within few days under air or a short-acting gas tamponade with little or no posturing at all. However, in my opinion, in order to achieve the highest possible closure rate, it is advisable to use gas tamponade, maybe long-acting, with 1-week head down positioning. This is almost compulsory for stage IV and some large stage III holes with considerable epiretinal traction.

Vlassis Grigoropolis, 2nd Ophthalmology Department, Henry Dunant Hospital, Athens, Greece

Fig. 9.69 A large macular hole initially reduced in size after PPV and gas but took 1 year to finally close after the surgery with recovery of 20/120 vision (see Figs. 9.70–9.73)

Fig. 9.70 See previous figure

Not all vitrectomy surgeons perform phacoemulsification; therefore, four protocols have been performed.

•Separate planned operations

–Cataract extraction then PPV

–PPV then cataract extraction

•Combined operation of simultaneous cataract extraction and PPV

•PPV then cataract extraction when symptomatic Simultaneous cataract extraction and PPV is favoured

here because of the rapid visual rehabilitation of the patient and the need for only one surgical episode. Surgery in this way produces increased flare (and increased risk of posterior synaechiae) and some risk of iris capture because the gas bubble may tilt the newly implanted IOL. Delaying the cataract surgery seems to run an increased risk of CMO formation, presumably from easier access of prostaglandins to the macula in an empty vitreous cavity. Also, be aware that the thickening of the retina at the edge of the hole can result in a falsely short axial length with some biometry systems creating a myopic error after IOL implantation.

9.2.4.8 Specific Complications

These are varied (Banker et al. 1997; Chang et al. 1999; Cheng et al. 2001; Park et al. 1995).

Cataract nuclear sclerosis progression is almost 100 % with a 76 % chance of requiring cataract surgery (Thompson et al. 1995). The high rate of cataract postoperatively has led some surgeons to perform the cataract extraction at the time of vitrectomy surgery (Lahey et al. 2002). Indeed, this is my preferred practice (see Chap. 2).

Retinal pigment epithelial changes 33 %.

Retinal breaks during surgery 12.7 % with PVD induction and 3.1 % without PVD induction (Chung et al. 2009).

RRD up to 6.6–14 % (Guillaubey et al. 2007) and is higher when the posterior hyaloid is peeled in stage 2 and 3 holes than in stage 4 (PVD already present).

Macular hole reopening has been described in 11 % (Bhatnagar et al. 2007) especially in those who have postoperative cataract extraction.

Choroidal neovascularisation rarely.