–The F-A-X can be repeated but remember that even then the oil removal will never be 100%.

•The patient must be warned that small, circulating dark circles may be seen for months postoperatively; these represent tiny oil droplets, which cannot be removed (without another surgery, and even then only to a certain degree), but they are harmless.

•Despite your best efforts, oil droplets may be present under the conjunctiva. These can bother the patient enough to warrant removal (see Fig. 35.2).

35.5Exchanges

Table 35.2 provides the rational and the technical details for most the commonly used exchanges, including the issue of the “fluid sandwich.” Only those that concern eyes with RD are discussed below.

•Air will push the subretinal fluid posteriorly; PFCL will push the subretinal fluid anteriorly.

–In principle, air is preferred if the break is central and PFCL if the break is in the periphery.

–In practice, air can effectively be used in almost all cases (see Table 35.3) – but it may be a technical challenge for the beginner surgeon (see Sect. 31.1.2).

•If the RD is old, the fluid is likely to be very viscous.52

•In an eye with macula-on detachment there is substantial risk of any remaining subretinal fluid getting pushed under the macula postoperatively. “Steamrolling” is called for,53 in which the gas bubble is brought over the macular area from attached retina.

35.6If the Eye Is Aphakic

Even today, the VR surgeon occasionally encounters an eye with no lens or IOL; this has a few special implications when tamponades are used.

•Air: if it fills the AC, the BIOM front lens must be adjusted. If F-A-X is planned and then silicone oil implanted, make sure to aspirate the BSS that is often trapped in the angle.54

–The presence of BSS is easily recognized because the air bubble does not completely fill the AC.55

52Active aspiration in the subretinal space with the probe may be necessary, which increases the risk of catching the retina or injuring the choroid.

53This must be explained to the patient in great detail. The maneuver is detailed under Sect.

54Also, remember to do an inferior iridectomy (see above, Sect. 35.4.4).

55That is, the diameter of the air bubble is much smaller than the diameter of the cornea.

•PFCL: intraoperatively it will not enter the AC, but if a bubble is inadvertently left behind, postoperatively the bubble will intermittently appear in the AC. It is always inferior if the patient is sitting. If the surgeon wants to remove this bubble, there are 2 options.

–Seat the well-anesthetized patient at the slit lamp. A nurse should hold the patient’s head against the bar to make sure he is not moving away. This is dangerous because the surgeon cannot adjust his progressively worsening image himself; therefore he will ask the patient to press against the bar – and since the blade or needle is already held in position to enter the eye, an inadvertent perforation may occur. The paracentesis should be inferotemporal and small.

–If the procedure is not legally allowed to be done outside the OR and the eye is aphakic, constrict the pupil before the patient lies down on the operating table. Adjust the table so that the patient’s forehead is higher than his chin (see the example on Fig. 16.5b, as opposed to on a). The removal is through a needle paracentesis on the temporal side, and the patient’s head must be turned toward the temporal side so that the paracentesis is at the deepest point of the AC.

(continued)

*The retina is attached, unless otherwise indicated.

aThe substitute enters the eye through the infusion cannula unless otherwise indicated. bBSS.

cOn a syringe; the injection is done by the surgeon, not the machine. dA double-barrel needle or a non-valved cannula may also be used.

eIn principle, “coating” the PFCL bubble with BSS may eliminate this problem; in practice, this is difficult to achieve.

fThe benefit of the fluid sandwich is financial: a smaller amount of PFCL is needed.

• Silicone oil: see above Sect. 35.4.4.

*See also Sect. 31.1.2.

aThe break should have been marked by diathermy to allow easy identification under air (see Sect. 54.5.2.3).

bTo avoid touching the choroid and causing a hemorrhage.

cThe alternative is using PFCL to keep the retina immobile, just remember the possibility and consequences of PFCL evaporation.

dThe air forms fish eggs before the bubbles coalesce – this may take an uncomfortably long period. e“The ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, gravity.” fHence the need to not move the tip of the needle while draining.

gIn such cases there are 3 options (see also Sect. 31.1.2). Redetach the retina and repeat the procedure (acceptable though not ideal); create and drain through a central retinotomy (don’t); or, if the fluid is minimal, silicone oil use is not planned, and the fluid can be kept out of the submacular space (steamrolling, see Sect. 54.6.3.1), leave it behind and the RPE will remove it within days. hIt takes several minutes to complete this step.

iThis is how a 100% fill can be achieved.