Intraocular pressure changes during injection of microincision and conventional intraocular lenses through incisions smaller than 3.0 mm.

PURPOSE

To compare intraocular pressure (IOP) during insertion of a new microincision intraocular lens (IOL) (Akreos AO MI60) and a conventional IOL (AcrySof Natural SN60AT) and to determine the minimum incision sizes for insertion in a cadaver eye model.

SETTING

John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA.

METHODS

After phacoemulsification in phakic cadaver eyes, multiple IOL insertions were attempted through 1.8 mm to 2.5 mm wounds. The final incision size and insertion success were evaluated in each case. A pressure transducer placed in the vitreous cavity measured real-time IOP changes (100 readings per second), including the mean and peak IOP during IOL implantation.

RESULTS

The minimum incision size for the microincision IOL insertion was 1.9 mm using a wound-assisted technique and 2.2 mm using a cartridge-insertion technique. The minimum incision size for wound-assisted implantation of the conventional IOL was 2.4 mm. During successful implantation, the mean and peak IOPs were similar between the 2 IOL types. The peak IOPs exceeded 60 mm Hg (retinal perfusion pressure). In unsuccessful attempts, the mean and peak IOPs were higher for the conventional IOL, reaching 306.05 mm Hg in 1 eye.

CONCLUSIONS

Monitoring during implantation of both IOL types confirmed that IOP increases during insertion, including during microincision surgery using a wound-assisted technique. Further studies are necessary to evaluate the effect of pressure spikes on the optic nerve during IOL insertion.