7.6.3.3 Trans-scleral Illumination Technique

The surgeon performs indentation of the external sclera with the bullet fibre optic light, which will provide illumination of the retina through the sclera.

1.Before starting, identify with endo-illumination which retina has already lasered.

2.Establish the area which requires treatment.

3.Point the laser probe at the unlasered retina.

4.Remove the light pipe.

5. Press the light pipe onto the sclera to indent the appropriate retina.

6.Laser around the anterior edge of the break.

7.Remove the laser probe.

8.With endo-illumination and indentation with a squint hook, check that the retina has been treated correctly. Note: Using the bullet light pipe to indent prevents the

problems of indentation using an assistant. However, the retinal laser burns are not well seen during this manoeuvre; the surgeon has to remember where the treatment was placed by using retinal landmarks and subconscious awareness of the three-dimensional structure of the eye.

Check the retina with endo-illumination to make sure that the laser uptake has been adequate.

7.6.3.4 Silicone Oil Insertion

Perform an exchange of silicone oil for the heavy liquids, allowing the oil to enter the eye, whilst draining subretinal fluid and peripheral fluid from the giant retinal tear. The heavy liquids will contact the silicone oil, spreading a doughnut of subretinal fluid and vitreous cavity fluid to the periphery, which then can be drained at the edge of the giant retinal tear. Theoretically, this manoeuvre is more effective with silicone oil/heavy liquid exchange than gas/heavy liquid exchange (Wong et al. 1998); therefore, a direct oil/heavy exchange is recommended.

Eventually, there is no subretinal fluid or vitreous cavity fluid to be drained, and the heavy liquids can be removed. Remember to remove the heavy liquid in one movement, thereby avoiding losing its location as the bubble of heavy liquid contracts. If a ‘stop and start’ method is used, it is possible to lose sight of the heavy liquid especially as it gets smaller in size.

7.6.3.5 Choice of Endotamponade

Many surgeons will use silicone oil as the preferred tamponade; however, if the GRT is less than 180°, perfluorocarbon gas can be used (Batman and Cekic 1999; Verstraeten et al. 1995) especially if the GRT is superiorly located. Failure with gas can lead to a high risk of PVR whilst silicone oil can cause toxicity and other well-known complications (Chap. 2). Attempts to use perfluorocarbon liquids for postoperative tamponade seem to be

associated with reduced primary retinal reattachment rates of approximately 50 % (Kertes et al. 1997; Banker et al. 1996). Scleral buckling has also been used as an addition to PPV and intraocular tamponade but is usually not necessary in the primary procedure (Ie et al. 1994; Hoffman and Sorr 1986).

7.6.3.6 Success Rates

These are high for reattachment of the retina at 87 % primary and 95 % secondary success (Ang et al. 2010) although visual acuities are affected by epiretinal membrane and postoperative cataract.

7.6.3.7 Removal of the Silicone Oil

The silicone oil can be removed at 2–4 months after the surgery, at which point it is recommended to reinspect the giant retinal tear internally and treat any portions of the tear which have retracted beyond the retinopexy or for which retinopexy has been inadequate.

7.6.3.8 The Other Eye

Some surgeons have advocated 360° laser retinopexy in the unaffected eye because of the risk of bilaterality (Ambresin et al. 2003; Ang et al. 2008). The evidence for treatment of the fellow eye is uncertain because of the poor structure of previous studies (Ang et al. 2009). Historically, the reported bilateral rate of GRTs is high especially in Stickler’s syndrome (25–40 %). Application of 360° cryotherapy has been reported to reduce this incidence to 6–10 % in retrospective studies (Ang et al. 2008; Wolfensberger et al. 2003). If applied, the hope is that the cryotherapy will restrict movement of a giant retinal tear if it occurs anterior to the laser. However, the procedure does have some risks of its own, and, therefore, it is not universally recommended.

7.7Retinal Detachment in High Myopes

7.7.1Clinical Features

Breaks in the macula in emetropic eyes do not usually cause retinal detachment (e.g. senile macular holes). In highly myopic eyes, posterior breaks, especially at the macula or nasal to the optic disc, often associated with areas of chorioretinal atrophy and with posterior staphylomas will often cause retinal detachment. The detachment usually remains at the posterior pole occasionally extending anteriorly if peripheral breaks are also present. The internal limiting membrane (ILM), vitreoschisis and partial vitreous separation (Matsumura et al. 2004) around the hole may be implicated in the pathogenesis of the retinal

Fig. 7.21 In highly myopic patients with posterior staphyloma, posterior RRD from breaks in the macula can occur

Fig. 7.23 A shallow retinal detachment in the posterior pole is seen in a high myope who has a foveal hole inducing retinal detachment

Fig. 7.22 A composite OCT picture showing the steep curvature of a myopic staphyloma

detachment because surgical removal of residual vitreous cortex and ILM during vitrectomy facilitates retinal reattachment, the retina remaining flat even if the hole is open postoperatively and untreated by retinopexy (Ikuno et al. 2003). Histopathology shows a fibro cellular component in the ILM in these cases (Bando et al. 2005; Sakaguchi et al. 2004). During follow-up, 8.5 % develop RRD in their fellow eyes in 5 years (Oie and Emi 2007). In addition, the retina of the macula may become schitic or even dome shaped without a retinal break but with an associated drop in vision. If followed, these eyes can develop macular SRF or macular hole (Shimada et al. 2006) and the staphylomas progress (Hsiang et al. 2008).

7.7.2Surgery

Additional surgical steps

1.Search the posterior pole for the break.

2.Stain the macula with brilliant blue or intravitreal triamcinolone acetonide.

3.Peel the vitreous cortex/ILM complex.

4.Insert air.

5.Exchange for long-acting gas.

Although gas injection and PPV alone can reattach these retinae (Blankenship and Ibanez-Langlois 1987), removal of the internal limiting membrane and residual vitreous cortex during PPV appears to increase the likelihood of success. A successful search for the macular retinal break is helpful. If this is found, it reassures the surgeon that there is unlikely to be a peripheral break to explain the findings. The atrophic breaks in these patients are not easy to find; check the fovea and the edge of any chorioretinal atrophy, for example, peripapillary atrophy. Use a flute needle to gently aspirate over the macular retina (not the fovea) to see if you can cause the hole to pout, but be aware that with excessive aspiration, you can produce a hole (especially in the fovea) with this method. The periphery should also be searched. Apply either Triamcinolone acetonide (Yamamoto et al.