sphere within the eye that will never be able to cover all areas of the inner surface of the eye. This is also true for so-called double tamponades of silicone oil and PFCL. These two substances will mix well, but then they will form an hourglass-shaped tamponade within the eye with one part trying to folate upwards and one part sinking down. As a result, a belt of ßuid surrounds the tamponade in the middle of the eye. Finally, a ÒcompleteÓ vitrectomy is not possible. Remnant vitreous will always lead to an incomplete tamponade.

2.5Dyes for Vitreous and Membranes

2.5.1Staining of the Vitreous

Staining: triamcinolone acetonide, trypan blue (Monoblue¨, Membrane Blue¨) Triamcinolone is a frequently used dye in vitreoretinal surgery. Many surgeons

inject it at the beginning of the vitrectomy because triamcinolone stains the vitreous well (comparable to asteroid hyalosis). In addition, triamcinolone is a popular staining agent for membranes but does not stain the ILM. Trypan blue can also be used instead of triamcinolone (Table 2.2).

Practical use: For the injection of dyes, take a 3 ml syringe and a 23-gauge backßush needle (Fig. 2.24). Inject before the vitrectomy 0.1Ð0.2 ml diluted triamcinolone, wait approximately 10 s, and then continue the vitrectomy. You will now be able to recognize the vitreous well.

Pits & Pearls No. 5

Triamcinolone can be cumbersome to remove. If you inject too copiously, it will cover potentially important details of the retina and slow down the procedure. Use only minimal amounts of triamcinolone for staining; you can always re-inject if necessary.

2.5.2Staining of Epiretinal Membranes

Staining: triamcinolone acetonide, Trypan blue (Monoblue¨, Membrane Blue¨, MembraneBlue Dual¨). Triamcinolone crystals stick onto the membranes, while Trypan blue stains the entire membrane. Our best experience has been with Monoblue¨. Practical modalities include: slow injection (syringe with a blunt cannula) of dye onto the posterior pole (Monoblue¨ is heavier than water), wait about 15 s, open the infusion, and remove the dye again with the ßuid needle.

Practical use: For the injection of dyes, take a 3 ml syringe and a 23-gauge- backßush needle (Fig. 2.24). Perform a PVD, inject dye slowly onto the posterior pole (Monoblue¨ is heavier than water), wait about 15 s, open the infusion, and remove the dye again with the ßuid needle.

2.5.3Staining of the Inner Limiting Membrane (ILM)

Staining: Brilliant Blue G (Brilliant Peel¨, ILM-Blue¨, MembraneBlue Dual¨). Indocyanine green (ICG) is controversial as it is potentially neurotoxic and may cause visual Þeld defects. Triamcinolone does not stain the ILM, and Trypan blue stains the ILM only weakly. We have had the best experience with Brilliant Peel¨.

Practical approach: Perform a waterÐair exchange; leave a small puddle of water. Inject 2Ð4 drops of Brilliant Blue G in the puddle and wait approximately 30Ð60 s. Then aspirate the puddle with the dye and perform an air/ßuid exchange. Advantage: The dye acts only in the water puddle, and the surgeon can remove it more quickly than if you stain the entire vitreous cavity. (See Chapter 5.3: macular holes and epiretinal membranes.)

Remark: An interesting dye is MembraneBlue Dual¨ (DORC). It contains both Trypan blue and Brilliant Blue G and can, therefore, stain membranes and ILM at the same time.