Placing the New Lens into the Eye
Continuing my series on what happens during cataract surgery, we have so far removed the cataract, but still have to place the new lens in the eye.
Provisc was then injected into the anterior chamber and capsular bag…
After phacoemulsification of the cataract and aspiration of the cortex, there is little remaining viscoelastic. In order to safely place the new intraocular lens (IOL) in the eye this gel must be replaced. This step also functions to open up the capsular bag and make it easier to position the IOL inside the bag. As much as possible we try to leave things as they were. What better place for the new lens than where the old lens (cataract) was: in the bag?
…following which the lens was inspected for proper power and good integrity.
I personally check the model and strength of the IOL before surgery and just before implantation in the eye. Although not all surgeons personally do this, I feel that this is something I should not delegate to someone else. Which IOL is placed in the eye determines the final vision after surgery. Pretty important step, wouldn’t you agree?
The lens was placed in the insertion device which was used to insert the lens through the temporal incision…
Not all lenses have to be placed in the eye using an inserter. Most lenses can also be folded. However, something must be done to the IOL in order to get it through the incision. Remember that the incision is only 2.2-3.6mm wide. Most IOLs have optics (round lenses) that are 5.5-6.0mm in diameter. Thus, they must be rolled, folded, or otherwise deformed in order to fit them through the corneal incision. Because they must be flexible, most modern IOLs are made of malleable materials such as silicon or acrylic.
…guiding the leading haptic into the capsular bag. The trailing haptic was positioned in the capsular bag using a lens manipulator.
The ‘haptics’ are flexible loops that stick out from the optic. These act to hold the lens in place and center it in the bag.
The remaining viscoelastic was then removed using automated irrigation and aspiration, taking care that no residual viscoelastic was trapped behind the optic.
Now that the cataract has been removed and the new lens is in the eye it is time to remove the protective gel. If it is left in the eye it will clog up the drainage system resulting in a high intraocular pressure after surgery. Many times, even with diligent removal of the viscoelastic material the pressure will still ‘spike’ up in the first 24 hours after surgery. However, this is often easily controlled with drops or by letting some of the fluid out of the eye through the paracentesis created at the beginning of the surgery.
Because the more advanced viscoelastics (which are thought to be more corneal protective) are more likely to remain in the eye after surgery I will go ‘behind the lens’ in order to remove as much as I can. Many surgeons choose not to take this extra step because it is risky without proper technique and difficult to do without a bi-manual irrigation and aspiration setup.
© 2009 David Richardson, MD