Sir,

The overall UK incidence of postoperative endophthalmitis is approximately one in 700,1 with an increase in incidence observed recently.2 Inflow of ocular surface fluid through sutureless-cataract surgery wounds has been observed in both laboratory3 and human studies.4 Contamination of aqueous by ocular surface bacteria can cause low-grade endophthalmitis5 and might have a role in the aetiology of endophthalmitis post-cataract surgery.

We demonstrate how introducing a small air bubble in the anterior chamber, at the end of sutureless cataract surgery, can prevent inflow of ocular surface fluid.

Case report

Digital video recording of 14 serial patients, showing bleeding from the limbal capillary bed were included. All wounds were 2.8-mm limbal incisions sealed by stromal hydration. Patient manipulation was simulated by external pressure and release of the speculum before and after injection of a 0.1 ml air bubble.

Spontaneous inflow of blood-tinged ocular surface fluid into the anterior chamber through the wound was observed in 2 out of 14 eyes (14.3%) (Figures 1, 2, 3 and 4). A further four patients (28.5%) demonstrated inflow with light speculum manipulation. In all six patients, inflow immediately stopped after the air bubble had been injected into the anterior chamber. The bubble disappeared after 24 h in all patients without complications.

Figure 1
figure 1

Patient 1—Spontaneous inflow of limbal blood.

Full size image
Figure 2
figure 2

Patient 1—Immediate cessation of inflow—blood is redirected around the limbus on air bubble introduction.

Full size image
Figure 3
figure 3

Patient 2—Spontaneous inflow into anterior chamber.

Full size image
Figure 4
figure 4

Patient 2—Cessation of inflow with air bubble—pooling of blood at limbus after air bubble introduction.

Full size image

Comment

Inflow of ocular surface fluid can occur with speculum removal at the end of surgery, and excessive squeezing or manipulation by the patient. We observe that the air bubble, which is compressible, allows the anterior chamber more compliance. This prevents wound leak and suction/inflow with positive and negative pressures created by external forces. This is especially crucial during the first 24 h after intraocular surgery.

Other advantages of the air bubble include: unrolling a Descemet's scroll, confirming the eye is not leaking (bubble does not get bigger), defocusing light after IOL implantation and so preventing macula phototoxicity, and buffering against postoperative intraocular pressure spikes. Pupil block, toxicity to the endothelium, and associated visual phenomenon were not observed in our study. The air bubble disappeared within 24 h minimizing such risks.This simple procedure may reduce intraocular contamination and rate of postoperative endophthalmitis.