Evaluation of flurbiprofen-exposed irises to acetylcholine anterior chamber irrigation

Effect of Flurbiprofen on Acetylcholine-Induced Pupillary Contraction

Preoperative treatment with topical nonsteroidal anti-inflammatory agents such as flurbiprofen (Ocufen) is used to maintain pupil dilatation during cataract surgery. Flurbiprofen maintains pupil dilatation by inhibiting release of prostaglandins and other modulators of surgical miosis. Some reports suggest that these agents may reduce the miotic effect of intra-operative acetylcholine (Miochol). It is hard to explain this effect unless there is a pharmacological interaction between the two drugs. This study aimed to investigate the possibility of a direct interference by flurbiprofen with the action of acetylcholine on the pupil sphincter.

Iris tissue of seven cadaver eyes were isolated and maintained in an organ bath containing Kreb's solution. Pupil contraction force induced by acetylcholine was measured in the presence and absence of flurbiprofen. Acetylcholine produced a mean pupillary contraction force of 52.4 × 10–3 N. When it was added to the organ bath in the presence of flurbiprofen the mean contraction force was 50.6 × 10–3 N (paired t-test P=0.68).

This study does not find any evidence to suggest that flurbiprofen reduces the pupil sphincter contraction that is induced by acetylcholine. It is likely that the apparent reduction in miosis is due to factors other than the mechanism of action of acetylcholine on the sphincter pupillae.

Does topical flurbiprofen affect the pupillary response to acetylcholine?

Pre-operative topical non-steroidal anti-inflammatory drugs (NSAIDs) are known to be effective in maintaining pupillary dilation during cataract surgery. However, previous studies have suggested that pre-treatment with these agents interferes with the miosis produced by intraoperative acetylcholine injection. This study was designed to determine whether the pupillary response to acetylcholine injection is reduced following pre-operative topical flurbiprofen 0.03%. Pupil diameters were measured with a millimetre rule, and the measurements verified using computerised image analysis of digitised video images. Eyes treated with flurbiprofen were compared with controls. There was no significant difference in pupillary diameter before corneal incision, but following aspiration of soft lens matter and insertion of intraocular lens the pupil was significantly larger in the flurbiprofen group (p = 0.002). At 1.0, 2.5 and 5.0 minutes following injection of acetylcholine no significant difference in the degree of miosis was detected. This study confirms that topical flurbiprofen maintains dilation during cataract surgery, and does not find any evidence to suggest that intra-operative response to acetylcholine is reduced.

Effects of topical suprofen and flurbiprofen on the miosis produced by anterior chamber irrigation with cholinergic agonists

Pretreatment with topical nonsteroidal anti-inflammatory drugs is common practice to maintain maximal pupil dilation for cataract surgery. Most surgeons also inject a cholinergic agent intracamerally for miosis after intraocular lens insertion. We evaluated the effects of topical suprofen and flurbiprofen on the miosis induced by anterior chamber irrigation with either acetylcholine or carbachol. One eye of 30 pigmented rabbits was dilated with cyclopentolate HCl and phenylephrine HCl. Three groups, each composed of ten eyes, received flurbiprofen, suprofen, or a control. In each group, five eyes received acetylcholine by anterior chamber irrigation and five received carbachol. Pupil diameters were measured with calipers before and five minutes after irrigation by an observer unaware of the treatment regimen. Irides irrigated with carbachol constricted less than those irrigated with acetylcholine (P = .016). In anterior chambers irrigated with carbachol, suprofen was associated with less miosis than either tears (P = .005) or flurbiprofen (P = .009); however, if the infusion was performed with acetylcholine, no differences between the three groups were noted (P = .44).

The effect of preoperative flurbiprofen on miosis produced by acetylcholine during cataract surgery

Sustained pupillary dilation during cataract surgery may be achieved with preoperative noncorticosteroidal anti-inflammatory agents such as flurbiprofen. However, these agents may interfere with miosis after injection of acetylcholine. Thirty patients for extracapsular cataract extraction were randomly assigned in a double-masked fashion to receive either a placebo or preoperative 0.03% flurbiprofen every 30 minutes for four doses. All patients also received three doses of 2.5% phenylephrine and 2% cyclopentolate. Pupillary diameter was measured the day before surgery, immediately before the surgical incision, immediately before and five minutes after acetylcholine injection, and the morning after surgery. The flurbiprofen group had a larger mean pupillary diameter before injection of acetylcholine (P less than .001), five minutes after acetylcholine (P less than .001), and on the first postoperative day (P less than .005).