2.11 Closing

2.10.4 Blood in the Anterior Chamber

If the IOP has dropped during surgery, blood can enter the anterior chamber from the trabecular meshwork. Alternatively, patients with severe vitreous haemorrhage may have a trickle of haemorrhage into the anterior chamber from the vitreous cavity. Perform a paracentesis and wash out the blood with balanced salt solution. If the haemorrhage is recurrent, viscoelastic can be inserted to displace the blood from the pupillary aperture. Remember to remove the viscoelastic later on.

2.10.5Condensation on an Intraocular Lens Implant

If the posterior capsule has been removed and gas is in contact with the IOL, condensation may occur on the back of the IOL. First, wipe the back of the lens with a ßute needle to add a layer of ßuid onto the lens. This is usually enough. If recurrent condensation occurs, add a small droplet of viscous ßuid HPMC or viscoelastic onto the posterior surface of the IOL and wipe again.

2.10.6 Cataract Formation

This will only occur peroperatively if the surgery is very prolonged so that the Þrst rule is safe but quick surgery. Preoperatively judge the lens clarity; if there is pre-exist- ing cataract, this should be removed by phacoemulsiÞcation and lens implantation at the commencement of the surgery. An already cataractous lens is much more at risk of worsening during surgery than a clear lens. In the rare event of a lens clouding, such that the posterior segment is compromised, stabilise the posterior segment (ßuid Þlled) and perform a phacoemulsiÞcation cataract extraction and PCIOL insertion and then continue the posterior segment surgery.

Fig. 2.28 Flow of ßuid close to the lens has caused localised lens opacity

2.10.7 Pupillary Dilation

The modern IVS allows visualisation through surprisingly small apertures, but if a larger pupil is desired, here are some methods:

1.Using a sub-TenonÕs LA injection will produce pupillary dilation.

2. An irrigation into the anterior chamber of 0.1 ml of 1 % Phenylephrine (one part of Phenylephrine 10 % with nine parts of balance salt solution) or 0.1 ml of 2.5 % Phenylephrine can be used.

3.Make sure posterior synaechiae have been divided by viscoelastic.

4. If the pupil remains constricted, use iris hooks to expand, but watch out for a postoperative Þbrinous reaction.

2.11Closing

Always close the superior sclerotomies Þrst and the inferior infusion sclerotomy last as this controls the IOP. When utilising gas tamponade, close one sclerotomy, keep the air pump on and attach the syringe with the gas to the three-way cannula, close off the air pump and then exchange the longacting gas by injecting through the infusion cannula. Inject at least 35 ml of the gas to ßush out the air in eyes with 25 mm or less axial length. In eyes bigger than this, the theoretical volume to achieve 97 % saturation of the gas mix in the syringe in the eye is more than 35 ml; therefore, two syringes should be used or use a 100ml syringe.