Optometry’s role in optimizing advanced technology IOLs

Cataract surgery remains one of the most commonly performed surgical procedures in the United States. Approximately 3.3 million cataract surgeries are performed annually, and that number is expected to rise dramatically by 2020.¹ With this growth in surgical demand, optometry must take a more active role in the surgical care of our patients, and we are well positioned to do so.

Dr. WhitleyAs the primary eyecare provider, who better knows and understands our patients’ vision needs then we do? No one. The primary goal with cataract surgery is to improve our patients’ quality of vision.With the introduction of advanced technology intraocular lenses (ATIOLs) almost a decade ago, we can provide our patients with not only improved quality of vision, but also improved quantity of vision. The purpose of this article is to provide co-managing optometrists clinical pearls to optimize outcomes for patients who elect ATIOLs.

Initiating thediscussion

There are several reasons why optometry needs to be involved with cataract surgery and ATIOLs. First, it is the right thing to do, and we need to be the ones to initiate this discussion. We know our patients best, and we need to educate our patients on every aspect of their upcoming procedure. Doing so establishes the important role that we have in patients’ pre-/post-cataract care and the comprehensive eyecare services that we provide.

Second, we can demonstrate our capacity to offer state-of-the-art technology. ATIOLs create a "wow" factor for our patients. A thorough discussion of the pros and cons of each technology should be initiated before a referral for surgery. ATIOLs are proven technologies with the majority of patients enjoying improved spectacle independence with proper patient selection and patient expectations.

Lastly, properly advising cataract and presbyopia patients on the availability of ATIOLs can help optometrists retain those patients. If a referral for surgery is made without discussing available treatment options, patients may consider other options for routine care following surgery.²

Understand theavailable ATIOL options

There are several ATIOLs available that are designed utilizing either refractive or diffractive technology. Refractive ATIOLs, such as the Crystalens AO (Bausch + Lomb [B+L]), have a smooth, continuous surface that bends light rays, focusing them into a single image. The Crystalens AO is an accommodating IOL in which the lens uses the natural focusing ability of the eye to provide a single focal point throughout a full range of vision from far to intermediate to near. Patients who require mostly distance and intermediate vision are best suited for this lens. For near tasks, additional reading glasses may be required, and informing patients prior to surgery will help them understand the limitations of this technology.

Diffractive IOLs include Tecnis Multifocal (MF) and Alcon ReSTOR. Diffractive IOLs have an optical surface that contains physical steps that divide light waves into wavelets that form both a distance and near image on the retina. Tecnis MF offers a fully diffractive multifocal that is pupil independent. Light waves are distributed equally to both a distance and near object. Alcon ReSTOR IOLs are the only multifocal that uses both apodized diffractive and refractive optics. The central 3.6 mm apodized diffractive surface distributes light waves to both a distance and near object using varying step heights. The outer zone of the ReSTOR technology includes an outer refractive portion that maximizes patients’ distance vision when the pupil increases in scotopic conditions. The ReSTOR apodized design helps to improve image quality and energy balance. Candidates best suited for these IOLs are patients who are motivated for both quality and quantity of vision, but understand the occasional glare/halos.

Addressing astigmatism

Many patients may need astigmatism correction, and there are several ways to do so. Just as we correct for astigmatism with glasses and contact lenses, cataract patients will benefit from astigmatic correction during cataract surgery. According to Ferrer-Blasco et al, up to 34.8% of patients have corneal astigmatism equal to or higher than 1.00 D.³ There are very few contraindications to the surgical correction of astigmatism because the goal is to optimize our patients’ vision. Treatment options for astigmatism include limbal relaxing incisions (LRIs) and toric IOLs. Several nomograms exist for LRIs, which can correct up to 3.00 D of astigmatism. This can be performed either manually or with femtosecond laser technology. Toric IOLs are refractive monofocal IOLs that can correct up to 4.00 D of corneal astigmatism. Patients with at least 0.75 D of corneal astigmatism are candidates for this technology. If patients elect for either an accommodating or diffractive IOL, any astigmatism can be treated with LRIs concurrently during the cataract surgery or several months later with laser vision correction.

Patientselection

Patient selection is crucial to optimizing surgical outcomes for our patients. Understanding our patients’ vision needs and matching those needs to the available technology will be critical to maximizing outcomes. One of the most important aspects of our discussion is determining which IOL is best for each individual patient. IOL options include:

• Monofocal for distance (glasses for near)

• Monofocal for near (glasses for distance)

• Monovision with monofocal IOLs

• Toric IOLs

• Multifocal/accommodating IOLs

The most commonly used ATIOL options include Alcon’s AcrySof Toric, Alcon’s ReSTOR, B+L’s Crystalens AO, and Tecnis Multifocal. Historically, the majority of patients choose the standard monofocal for distance vision. However, one reason why many patients choose the standard IOL is that nobody has told them there were other options available. Patients are looking to us as their optometrist for guidance on the cataract procedure and which IOL technology is best suited for them.

A thorough review of each patient’s previous ocular surgeries, as well as their medical and ocular history, will help determine appropriate candidates. Certain medications and conditions may have an effect on both the diagnostic and surgical procedure. The use of systemic antihistamines can exacerbate dry eye disease, which will impact IOL calculations and postoperative healing. Another example would be the use of tamsulosin (Flomax) for patients with a history of benign prostatic hyperplasia, which would affect adequate pupil dilation during surgery. Any previous history of ocular pathology will rule out several of the ATIOLs especially the diffractive IOLS like the ReSTOR or Tecnis Multifocal (see “Anatomical Considerations for ATIOLs”).

Personality characteristics are also important considerations. First, the patient must be motivated to reduce dependence on glasses for both distance and near vision tasks. Tools such as the Dell Questionnaire are useful to determine which distances are most important to our patients (see Figure 2). Second, patients must be willing to accept that ATIOLs have some limitations, including glare/halos, and the potential for inadequate vision at intermediate, near, and night vision tasks, depending on the ATIOL selected. For instance, a patient who drives frequently at dusk or nighttime may be best served with an accommodating monofocal such as the Crystalens AO. Or a patient who is motivated to achieve spectacle independence at all distances but doesn’t go out or drive at night may be better suited with a ReSTOR +3.00.

The identification and aggressive treatment of ocular surface inflammatory diseases, such as dry eye disease and blepharitis, are important prior to the referral for surgery. These conditions have a tremendous impact on the ocular surface, which can lead to poor IOL calculations preoperatively and exacerbate symptoms postoperatively. Any miscalculation by ± 0.5 mm due to a poor tear film can lead to refractive error of ±1.50 D. For this reason, these conditions cannot be overlooked. With aggressive treatment with artificial tears, topical anti-inflammatories, and punctal occlusion, patients may still be good candidates for ATIOLs.

Advanced diagnostic technology and biometry has also helped to improve our patient selection process. Several diagnostic technologies that are useful in gathering these measurements include the IOL Master (Zeiss), Lenstar (Haag-Streit), OPD-III (Marco), Orbscan (B+L) and the Pentacam (Oculus). These technologies provide useful measurements in IOL calculations including refractions, pachymetry, lens thickness, pupillometry, keratometry, axial length, anterior chamber depth, white-to-white measurements, and wavefront analysis. A thorough evaluation with these technologies allows eyecare providers to select appropriate IOL options and rule out non-candidates for ATIOLs.

“By identifying angle kappa and higher order aberrations such as coma prior to the procedure, we can better select patients for ATIOLs and optimize their visual outcomes,” said Steve Scoper, MD, cataract surgeon with a group practice in Norfolk, VA. For example, if a patient has a high-angle kappa, he or she may not benefit from the diffractive optics due to the large misalignment between the pupillary axis and the visual axis. This patient would be better suited for a standard monofocal or an accommodating monofocal IOL. Regarding coma, selecting patients with minimal coma measurements will likely result in less postoperative visual disturbances, such as glare and halos.

Postoperative considerations

Optometrists play just as an important role postoperatively as we do preoperatively. Understanding the benefits and limitations of ATIOLs and addressing any patient concerns will help optimize the surgical outcome. Checking visual acuities at all distances will provide a baseline of the range of our patients’ vision. An evaluation of normal healing patterns at each visit whether at the one-day, one-week, or one-month visit and addressing any patient concerns about their “new vision” is warranted.

Careful consideration is needed for patients who may not have had the optimal result. The most common reasons for decreased vision after cataract surgery include ocular surface disease, cystoid macular edema (CME), posterior capsular opacification (PCO), and residual refractive error. If any of these conditions is found, it is important to address them and communicate with the surgeon. All vision fluctuations are due to ocular surface disease; aggressive treatment with artificial tear supplements, topical anti-inflammatories, and punctal occlusion will be necessary. Any decrease in vision due to CME or PCO development may necessitate early intervention and a referral back to the surgeon. If CME develops, patients may need a sub-tenons or intravitreal injection of triamcinolone. As for PCO development, because even a mild presence of PCO can degrade the quality of vision of ATIOLs, surgeons may elect to perform a YAG laser capsulotomy as early as 1 month.

Residual refractive error also may need to be addressed. Before any further intervention, ask the patient if he is happy with his results. Remember, the goal of ATIOLs is 20/happy, not 20/20. If our patients are unhappy with the outcome and have a residual refractive error, treatment options include a mild spectacle correction or additional laser vision correction. The key here with any of these concerns is to discuss with the patient and the surgeon to determine the best course of action.

Communicationpearls

Successful co-management is the result of continuous communication among all parties involved. The patient, co-managing optometrist, and surgeon must all be on the same page. Patients need to be educated on all their IOL options and understand the goals and limitations of the procedure. As the co-managing optometrist, we need to help set the stage by discussing with each patient who to go to for surgery, how the surgery is performed, IOL options available, which IOL option we believe is optimal for that patient, and what our role is in postoperative care. A direct referral should be made by the optometrist to the surgeon in addition to sending any pertinent patient notes and recommendations. After surgery, the surgeon and the co-managing optometrist should communicate through dictated letters, progress notes, or documented phone conversations to ensure proper patient care. In the event of either a complication or unmet patient expectations, the surgeon and optometrist should communicate and determine if any additional treatments are necessary.

This is an exciting time for cataract surgery. Never before have we had so many options that can address and improve a patient’s quality of vision. ATIOLs have proven to be successful in our cataract patients with proper patient education and patient selection. With continuous advancements in surgical techniques and innovations in science and technology, the precision, accuracy, and outcomes of cataract surgery will continue to provide our patients optimal vision and address their vision needs.ODT

References

1.   Congdon N, et al. Prevalence of cataract and pseudophakia/aphakia among adults in the United States. Arch Ophthalmol. 2004 Apr;122(4):487-494.

2.   Karpecki, P. Premium intraocular lenses. Optometry. 2009 Dec;80(12)525-528.

3.   Ferrer-Blasco, T, et al. Prevalence of corneal astigmatism before cataract surgery. J Cataract Refract Surg. 2009; 35:70–75

Anatomical Considerations for ATIOLs

(Courtesy of Scott Hauswirth, OD, and Elizabeth Davis, MD)

• Careful consideration with diseased or compromised corneas, including anterior basement membrane dystrophy, untreated ocular surface disease of any type, previous RK, previous laser vision correction, corneal scars, pterygia, or Salzmann’s nodules
• Obtain baseline topography

• Consider corneal procedures (PTK, superficial keratectomy) prior to cataract surgery
• Avoid in patients with irregular astigmatism

• Avoid in glaucoma patients with visual field defects

• Avoid in potentially unstable capsular bags (trauma, pseudoexfoliative glaucoma)

• Avoid in retinal disease (h/o retinal detachment, age-related macular degeneration, diabetic retinopathy, macular hole, epiretinal membrane, etc.)
• Consider baseline OCT to rule out
• Consider status of other eye; ATIOLs work best in both eyes, although in patients can be placed in select monocular patients

• Carefully assess astigmatism and have the ability to treat if 0.75D or more
• Obtain pachymetry and topography to assess for future laser vision correction

Author Info

Walter O. Whitley, OD, MBA, FAAO, is the director of optometric services for a group practice in Norfolk, VA. E-mail him at wwhitley@vec2020.com. Dr. Whitley is a paid consultant to Alcon Laboratories and Bausch + Lomb.

Take-Home Message

A boom in demand for cataract surgery calls for optometry to take a more active role in the surgical care of our patients. Part of that responsibility requires optometrists to know the options of advanced technology intraocular lenses (ATIOLs) and which lens will best meet the needs of each patient.