Offer options to your cataract patients

March 21, 2017

Article

As primary-care optometrists, we are the gatekeepers for baby boomers inquiring about cataract surgery. Today’s patients have treatment options available not only to address their lifestyle complaints but to provide them with better vision and possibly reduced dependence on glasses or contact lenses.

This generation of active seniors are eager to embrace their intraocular lens (IOL) options. They include both traditional cataract surgery and femtosecond laser surgery.

Many optometrists assume that patients already know what cataracts are. I find most patients think cataracts are a “film over the eye.” It is important for patients to understand cataracts so they can better realize why their vision is changing, and the cause of the glare at night when they drive, read, or watch television. Together, we pinpoint their lifestyle complaints-once the cataract is removed, we see if the complaints have been resolved.

The analogy of a camera works very well to explain to patients the basic optics of light entering a normal eye as well as diffraction when light passes through a cataract. I explain that the natural lens in our eye focuses light onto the retina, and over time this lens gets cloudy and loses its ability to change focus. This leads to presbyopia and eventually cataracts. Online resources can demonstrate this very well.

Previously from Dr. Fluder: Identifying common macular conditions with OCT

Explaining procedures

Your patients will have a flood of questions about cataract surgery. They will ask if it will be performed at a hospital or an outpatient facility, how long the procedure takes, and which surgeon will perform the procedure.

I recommend contacting your comanaging surgeons to obtain their protocols so you can better prepare your patients’ expectations. Patients will feel much more comfortable and have a sense of continuity of care if what you say is reiterated at the surgeon’s office.

I explain that we operate on only one eye at a time. If patients require IOLs in both eyes, the surgeries are scheduled one to two weeks apart. Cataract surgery is an outpatient procedure, and the patient will be in the surgery center for approximately two hours, with the procedure taking only 15 to 20 minutes.

In general, patients experience no pain, no patching, and no sutures. We numb the eye with a local anesthetic, dilate the pupil, and give patients medication, usually Versed (midazolam, Roche), under the tongue to relax them.

I use an eye model while explaining the procedure and point out the structures as I talk. Patients will typically better understand the procedure if they see the structures of the eye. I have found that the biggest misconception of cataract surgery is that patients believe they no longer have to wear eyeglasses or contact lenses. This is very important to clarify with your patients.

Patients having cataract surgery need to be informed that they will be seeing you again during the postoperative period if you comanage cataract surgery or they will be seeing you after their postoperative care for a new eyeglass prescription.

Preop clinical concerns

During your preoperative exam, be sure to examine the lids and tear film. Starting patients on warm compresses and lid scrubs twice a day and artificial tears four times a day before the surgical consult helps to ensure accurate measurements. This is very important for patients interested in advanced technology lenses along with femtosecond laser surgery.

Patients with significant map-dot-fingerprint corneal dystrophy may not be ideal candidates for laser surgery. Patients with corneal dystrophy, age-related macular degeneration, previous refractive surgery, or other ocular conditions (such as keratoconus or a history of retinal detachments) may not be candidates for multifocal IOLs.

Watch for large or small pupils and iris atrophy. Patients with large pupils are at a greater risk for experiencing glare postoperatively. Small pupils can cause concerns regarding a centered capsulorrhexis. Patients with iris atrophy are at risk for glare, light sensitivity, and weak zonules.

After your exam and patient discussion, it is up to you to offer the cataract surgery options that best fit your patient and his lifestyle.

Regardless of which surgery the patient receives, both options begin with IOLMaster (Zeiss) data. It is the gold standard in optical biometry. It will show IOL power selections, keratometry, anterior chamber depth, and axial length. Its Haigis-L formula helps determine surgical parameters for patients with a history of myopic/hyperopic LASIK. The newer 700 model incorporates swept-source OCT technology into biometry, allowing it to detect tilt or decentration of the crystalline lens.¹ It eliminates the need for A-scans because it is able to scan through dense cataracts. It also performs toric IOL calculations.

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.

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.

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.

Premium IOLs

All IOL manufacturers offer plenty of printed material as well as animated video to show your patients their options. These resources can help patients better understand the benefits of premium IOLs.

If a patient is interested in a multifocal IOL, I adhere to the recommended guidelines for patient candidacy. Our office works mainly with Alcon IOLs, so I have more experience with them. We like the patient to be hyperopic; however, these patients tend to have a larger angle kappa.

Angle kappa is the difference between the pupillary axis and the visual axis (Figure 5).⁵ It is defined as the angle between the visual axis (line connecting the fixation point with the fovea) and the pupillary axis (line that perpendicularly passes through the entrance pupil and the center of curvature of the cornea).

It can be identified clinically by the nasal displacement of the corneal light reflex from the pupil center, and it represents a misalignment of light passing through the refractive surface of the cornea and the bundle of light formed by the pupil.⁵ Angle kappa is not affected by gender, and it tends to decrease with age.

A large angle kappa is important clinically because it may lead to alignment errors and decentration during laser refractive cataract surgery. Decentration of the IOL can lead to photopic phenomena (glare and halos) as well as decrease in lens effectiveness. An option to compensate for a large angle kappa is to purposely decenter the IOL toward the visual axis. Centering the IOL on the corneal reflex will greatly reduce the incidence of photopic phenomena. A decentered IOL can decrease multifocal function.

Let the patient know multifocal IOLs are not for everyone, and clinical measurements will determine if the patient is a good candidate.

Higher order aberrations consist of spherical aberration, coma, and trefoil. Corneal coma is an imperfection that results in off-axis point sources such as stars appearing to have a tail-or coma. Vertical coma is the most common higher order aberration in patients with keratoconus, corneal injuries, or abrasions.⁶

One study involving 119 eyes undergoing uncomplicated cataract surgery with a 2.2-mm incision showed those patients who received a superior incision showed significant negative changes in vertical coma. Patients who had a nasal incision showed significant changes in oblique trefoil, and those that had a temporal incision had insignificant changes in higher order aberrations.⁷

We make sure the corneal coma is less than 0.32 µm for each eye. The angle kappa should be less than 0.43 mm for ReStor (Alcon) and 0.50 mm for Tecnis (Johnson & Johnson Vision Care) IOL. Also, the photopic pupil size should be no smaller than 2.0 mm and the mesopic pupil size no larger than 6.00 mm. I find this data on Marco OPD.

Patients who currently wear multifocal contact lenses may also be good candidates. They tend to have more realistic expectations as well as those with an easy-going personality.

Tell patients the brain will learn to adapt to the new vision with an IOL. This is called neuroadaptation, and it can take several months to adapt. Look at the patient as a whole. For example, a patient who is a +6.00 D hyperope with a mature cataract will be thrilled with her new vision. However, a -3.00 D myope with mild to moderate cataracts may be a bit more critical of the results.

AcrySof IQ ReStor +2.50 D (Alcon) features the company’s ActiveFocus optical design with seven diffractive steps. It has a distance center with a large peripheral zone that allows more light to the distance focal point as the pupil diameter increases and an apodized diffractive multifocal zone. This IOL is designed for individuals with an active lifestyle wanting distance and intermediate vision.²

If the patient has 1.00 D or more of corneal cylinder, we opt for toric IOL instead of a standard implant.

AcrySof IQ Toric (Alcon) IOL is a biconvex toric with aspheric design and ranges from +6.0 to +34.0 with seven cylinder powers. I use the company’s online calculator (acrysoftoriccalculator.com) to calculate the toric power and axis placement.

I also use an online visual simulator which shows patients simulated visual results with an IOL for activities including golfing, gardening, shopping, and night driving. Enter the patient’s astigmatism, level of cataract development, and IOL option to demonstrate the visual outcome. Obviously, results may vary, but it is a great way to demonstrate a patient’s expected visual results with various IOL options.

We also implement the ORA System with VerifEye+ technology. It offers real-time intraoperative IOL sphere, cylinder, and alignment suggestions. This is especially useful in the operating room for patients with a history of refractive surgery, including LASIK, PRK, and RK procedures. It helps to account for both anterior and posterior corneal astigmatism. The goal is to reduce the incidence of unintended residual postoperative astigmatism.²

After the surgery

Complications associated with cataract surgery are rare. Cataract surgery is one of the most successful procedures performed in the United States.⁸ However, it can include bleeding, retinal detachment, and infection. I assure patients that they will be using antibiotics to prevent infection. Bleeding is usually limited to the conjunctiva and will resolve in one to two weeks.

We let our patients know there are no restrictions. I tell them they can bend, lift, shower, shampoo, and do all their usual activities. We ask them to avoid swimming or hot tubs for a week. Patients can usually drive after the one-day postoperative appointment as long as pupil dilation is resolving and they feel comfortable driving. Always check the visual acuity of both eyes. It is common courtesy to send a short postoperative report to the surgeon.

References

1. Carl Zeiss. Zeiss presents the new IOLMaster 700 for better predictability and optimized workflows in cataract surgery. Available at: https://www.zeiss.com/meditec/int/media-news/press-releases/iolmaster-700-with-swept-source-biometry.html. Accessed 3/15/17.

2. Alcon. The AcrySof Advantage. Available at: https://www.myalcon.com/products/surgical/acrysof-iq-cataract-iols/index.shtml. Accessed 3/15/17.

3. Marco. OPD-SCAN III Wavefront Aberrometer. Available at: https://marco.com/products/wavefront-aberrometry/opd-scan-iii-wavefront-aberrometer/. Accessed 3/15/17.

4. Nagy ZZ, KrÃ¡nitz K, Takacs AI, MihÃ¡ltz K, KovÃ¡cs I, Knorz MC. Comparison of intraocular lens decentration parameters after femtosecond and manual capsulotomies J Refract Surg. 2011 Aug;27(8):564-9.

5. Moshirfar M, Hoggan RN, Muthappan V. Angle Kappa and its importance in refractive surgery. Oman J Ophthalmol. 2013 Sep;6(3):151-8.

6. Gordon-Shaag A, Millodot M, Ifrah R, Shneor E. Aberrations and topography in normal, keratoconus-suspect, and keratoconic eyes. Optom Vis Sci. 2012 Apr;89(4):411-8.

7. Seok Song I, Hoon Park J, Hyoung Park H, Young Moon S, Yong Kim J, Joon Kim M, Tchah H. Corneal coma and trefoil changes associated with incision location in cataract surgery. J Cataract Refract Surg. 2015 Oct;41(10):2145-2151.

8. Torpy JM, Lynm C, Glass RM. Cataracts. JAMA. 2003;290(2):286.