Fig. 2.25 To clear a view from corneal oedema, debride the epithelium with a blunt knife

adherence. For certain difÞcult macular procedures such as the commencement of internal limiting membrane peel, these can be useful as the membrane can be discriminated from the nerve Þbre layer more easily. The Þeld of view is much reduced and the view no longer inverted. Be careful when inserting the instruments; it is a long time before they come into view compared with the IVS. If you are using angled instruments, take care that you know where the heel of the instrument is in the eye. It is possible to touch the retina with it whilst watching the tips of the forceps. In addition, there is a tendency to have the light pipe closer to the retina risking light toxicity.

2.10Maintaining a View

Stop and examine all elements in the system.

2.10.1 Microscope

Make sure each portion of the microscope is correctly attached and orientated, for example, laser Þlter, stereo inverter, illumination.

2.10.2 IVS

Inspect the alignment of the IVS and that it is securely attached. Check all the lenses are clean. Condensation can develop on the IVS lens especially if the drape does not adhere to the skin around the nose. This allows exhaled air to escape and contact the lens. Replace the drapes if necessary. Cold

Fig. 2.26 Condensation occurs on lens implants when a posterior capsulotomy has been performed. This can compromise the view during surgery when air is inserted

Fig. 2.27 By gently wiping the posterior surface of the lens with the blunt instrument, ßuid can be passed over the lens and the view restored. Should the condensation return, some viscoelastic can be placed on the back of the lens and wiped which will retain the view

lenses are more prone to condensation which is more likely to happen when close to the cornea. Move the lens further from the eye until it gradually warms to room temperature. Wiping the lens clears the condensation temporarily.