Standard phaco surgery
Unless otherwise specified, our goal is to reduce the patient’s dependence on her glasses. We will decrease myopia or hyperopia as much as we can with standard phaco cataract surgery. Remember, however, that astigmatism is not being addressed, and residual myopia or hyperopia may persist. It is important to explain astigmatism and review the amount of astigmatism the patient has.
I next explain how femto cataract surgery addresses astigmatism. The laser will make incisions in the cornea to relax small amounts of astigmatism. The laser can usually relax up to 0.75 D corneal cylinder.
I make sure patients understand that standard phaco cataract surgery begins with a small incision in the cornea. With the pupil dilated, the surgeon will make a capsule opening on the lens and break up the lens with ultrasound. Next, the surgeon will vacuum the lens through the corneal incision and insert a lens implant in its place.
Related: Integrating laser cataract surgery
I have a sample implant so patients can see for themselves what is being placed in the eye. Be prepared to answer concerns regarding implant rejection or “going bad,” IOL replacement, or dislodged or loosening IOLs. These may seem like silly questions to us, but to the patient these are very real concerns.
Femto laser surgery
If the patient is interested in femtosecond laser refractive cataract surgery, we obtain biometric scans with an IOL Master, Verion Image Guided System (Alcon), and OPD-Scan (Marco). We compare the astigmatism data from all three scans to ensure consistency. For contact lens-wearing patients, we recommend repeat measurements after discontinuing lens wear for several days.
Verion (Figure 1) offers precision and consistency for refractive cataract surgery when fitting multifocal and toric IOLs. It captures the landscape of the patient’s eye by taking a high-resolution digital image useful for referencing in the operating room.
This “fingerprint” of the eye allows for precise positioning of incisions and real-time accurate alignment. Verion will provide IOL selection, primary and secondary incision locations, capsulorhexis location, surgically-induced astigmatism (SIA), and lens positioning. Because Verion knows the exact landscape of the patient’s eye, it will automatically track in real time and adjust for any eye movements, including cyclorotation.2
Marco OPD-Scan III (Figure 2) is a corneal analyzer that uses wavefront data to perform autorefraction, keratometer, Placido disc topography, wavefront aberrometry, lenticular residual astigmatism, angle kappa, pre and post toric IOL measurements, mesopic and photopic pupil sizes, Zernike graphs, corneal refractive power map, and IOL tilt/decentration.3 I rely on the corneal coma, angle kappa, and mesopic and photopic measurements for patients interested in a multifocal IOL.
Related: New eye drops could cure cataracts
The femtosecond laser procedure begins by first making the capsulorhexis (Figure 3). A femtosecond laser capsulorrhexsis is more regularly shaped, has better centration, and shows better intraocular lens/capsule overlap than a manual one.4
Next, the laser performs nuclear division. I inform my patients that there is more precision and less stress on the eye with the laser because less ultrasound is being used. Then stair-step primary and secondary incisions are made.
The patient is then transferred from the laser room to the operating room where the rest of the procedure is performed. Patients with small fissures, deep-set eyes, prominent brows, or significant blepharospasm may not be candidates for femtosecond laser if the surgeon does not feel confident docking on the globe. (Figure 4) Aligning the laser to the patient takes about five minutes. Local anesthesia is used, and the laser procedure itself takes only 30 seconds.