Improving quality of life through better vision outcomes

ByKerry D. Solomon, MD

Kerry D. Solomon, MD
Kerry D. Solomon

Correcting presbyopia through IOL implantation during cataract surgery presents an opportunity to improve far more than just the visual outcomes of our patients. Ophthalmologists already know that patients are looking for improved distance, near and intermediate vision. Yet, it is the quality of the resulting vision provided to the patient that has the potential to impact far more than what is present in the visual field at a given distance. What presbyopic patients really desire these days is functional distance vision and functional near vision, and being able to do more daily activities without dependence on glasses.

Many lens options are available to patients, each with unique properties that affect resulting vision in different ways. For the scope of patients seeking modern cataract surgery, this is an advantage because surgeons can better match IOL type with patient needs. Surgeons can tailor correction to the specific needs of patients, and for those patients seeking spectacle independence postoperatively, the ReSTOR +3 (Alcon) is a strong consideration. Providing functional near and intermediate vision in addition to distance vision in this manner may improve patient quality of life.

Managing patient expectations

If ophthalmologists are to achieve the best outcomes possible with advanced technology lenses, it is incumbent on all of us to ensure patients have reasonable expectations. From an anatomic perspective, patients with more than 1.0 D of preoperative astigmatism may be poor candidates for these kinds of lenses, because any impairment in the visual axis could yield uneven results.

“Correcting presbyopia through IOL implantation during cataract surgery presents an opportunity to improve far more than just the visual outcomes of our patients.”
— Kerry D. Solomon, MD

Patients also need to understand what is reasonable to expect from postsurgical results. Advances in lens technology and surgical techniques over the past decade have revolutionized the procedure and, as a result, the kinds of corrections we are capable of achieving. However, owing partially to the success of refractive practices, there may exist some misconceptions about what patients should expect. Simply put, we have come to expect very predictable, very accurate outcomes with PRK and LASIK techniques in our practice, but we are not as precise with our cataract refractive outcomes.

In my own practice, using the iFS intralase (Abbott Medical Optics) and VisX CustomVue (Abbott Medical Optics) treatment, about 93% of patients achieve 20/20 vision. About 50% of my patients achieve 20/15 vision, and almost all of my patients are within 0.5 D of the preselected visual target.

Although a direct comparison to cataract surgery outcomes is invalid, there is still a significant difference in posttreatment vision between these two procedures. Even if cataract surgery is performed with accurate biometry and modern, minimally invasive techniques are used, about 15% to 20% of patients will still need some sort of postsurgical enhancement to achieve the vision they expect.¹

In the interest of managing patient expectations, it is important to make sure patients understand that the requirement for an enhancement is not the result of bad surgery. Patients who are going to receive advanced technology IOLs should be told that even if surgeons do everything right, there is still a 20% chance they might need a touch up to get their best final vision without glasses. That is not a complication if we explain it ahead of time; that is just where we are with modern technology.

Lens comparisons

Presbyopia-correcting IOLs fall in to two basic categories: multifocal IOLs incorporating different refractive zones and accommodative IOLs that mimic the human eye’s ability to focus on near and distant objects. Each IOL available on the US market has unique properties, and each offers a different type of vision that may or may not be appropriate for a given patient. How these lenses are matched to the vision needs of patients really defines the success of the resulting vision correction.

One way to think about the type of vision correction offered by an IOL is to consider at what distance patients can see comfortably. For instance, laboratory testing showed that the ReSTOR +4 lens (Alcon) provides optimal near vision at around 13 cm.² There is a slight drop off in vision in the intermediate zone, and then a significant jump in vision quality for distance.

Figure 1: In laboratory models, the ReSTOR +3 provided optimal near vision at around 16 inches to 20 inches, with far less defocus at intermediate distances.

Adapted from data in: AcrySof ReSTOR +4 IOL Directions for Use.

The Tecnis multifocal (Abbott Medical Optics) lens has a similar defocus curve as the ReSTOR +4.³ However, for patients more reliant on intermediate vision—i.e., to use a computer screen—the ReSTOR +3 lens may be a more appropriate choice. In laboratory models, the ReSTOR +3 provided optimal near vision at around 16 inches to 20 inches, with far less defocus at intermediate distances (Figure 1).⁴ The difference in vision between these two lenses has also been shown in clinical trials.

In a randomized, prospective, multicenter study performed at four sites, 62 patients received either bilateral ReSTOR +3 or bilateral Tecnis +4 lenses.⁵Preliminary 1-month postoperative data showed patients achieved similar uncorrected distance and near vision results. However, patients with the ReSTOR +3 achieved better intermediate vision at 40 cm than patients with the Tecnis +4. In addition, results from a VISTAS questionnaire showed patients who received the ReSTOR+3 reported less difficulty performing tasks at various distances than patients who received the Tecnis +4. Although distance vision was equivalent, the ReSTOR +3 provided better near and intermediate vision than the +4 optic found in the Tecnis multifocal (Figure 2).

Figure 2: Although distance vision was equivalent, the ReSTOR +3 provided better near and intermediate vision than the +4 optic found in the Tecnis multifocal.

Adapted from data in: Solomon K. Enhancing the quality of life. Presented at: Hawaiian Eye 2011. January 17, 2011. Maui, Hawaii.

A significant difference in the vision of patients has also been shown in trials of patients implanted bilaterally with the ReSTOR +3 IOL compared with the Crystalens HD (Bausch + Lomb). In a head-to-head trial, patients in the ReSTOR IOL group, on average, achieved 20/20 near uncorrected visual acuity at around 40 cm.⁶ The mean uncorrected near visual acuity of patients in the Crystalens HD group at 40 cm was 20/50.

In terms of preferred distance for near vision, patients in the ReSTOR +3 IOL group saw around 20/20 at 38 cm. However, in the Crystalens HD group, patients achieved their best vision—around 20/32—at 51 cm (Figure 3). In the study, ReSTOR IOL patients were able to see more clearly and at a more functional distance than the Crystalens patients.⁶

Figure 3: In terms of preferred distance for near vision, patients in the ReSTOR +3 group saw around 20/20 at 38 cm. In the Crystalens HD group, patients achieved their best vision – around 20/32 – at 51 cm.

Adapted from data in: Lane SS. Visual Acuity with Spectacle Wear with Presbyopia-Correcting Intraocular Lenses. Poster Presented at: International Society of Refractive Specialists. October 16-19, 2010. Chicago.

The manifest refraction spherical equivalent was also superior in the ReSTOR +3 group due to its predictability: 100% of patients were within 1.0 D of target and 87% were within 0.5 D, compared with 79% and 64%, respectively, in the Crystalens HD group (Figure 4). More patients in the ReSTOR +3 IOL group never needed glasses (83%) and none of the patients were dependent on glasses full time. Comparatively, only 38% of Crystalens patients were spectacle independent, while 8% required glasses full time.⁶

In conclusion, if ophthalmologists are going to provide functional vision—that is, the ability for patients to do more activities at a comfortable distance without having to be dependent on glasses or contacts—results show that the ReSTOR +3 lens provides better functional vision for visual needs of patients for distance and near acuity, and presumably better quality of life compared with the Crystalens HD.

Figure 4: In a head-to-head trial, the manifest refraction spherical equivalent was superior in the ReSTOR +3 group: 100% of patients were within 1.0 D of target and 87% were within 0.5 D, compared with 79% and 64%, respectively, in the Crystalens HD group.

References:

Data on file with Dr. Warren Hill.
AcrySof ReSTOR +4 IOL Directions for Use.
Tecnis Multifocal IOL Package Insert.
AcrySof ReSTOR +3 IOL Directions for Use.
Solomon K. Enhancing the quality of life. Presented at: Hawaiian Eye 2011. January 17, 2011. Maui, Hawaii.
Lane SS. Visual Acuity with Spectacle Wear with Presbyopia-Correcting Intraocular Lenses. Poster Presented at: International Society of Refractive Specialists. October 16-19, 2010. Chicago.

Dr. Solomon is Director, Carolina Eye Physicians and Adjunct Clinical Professor at the Storm Eye Institute, Medical University of South Carolina, in Charleston, South Carolina. He is also a member of the Ocular Surgery News editorial board.