Exceptional Visual Quality With No Trade-Offs
Exceptional Visual Quality With No Trade-Offs
PureVision2 HD For Astigmatism delivers what patients say they want
Dr. Quinn: One way we, as eyecare practitioners, can describe how we serve our patients is “to help them live better by seeing better.” I think we agree that in order to do that we have to determine our patients’ needs, which means we have to learn about them. Toward that goal, when you walk into an exam lane with a patient waiting for you, what do you want to know about him or her?
Dr. Marsden: In the case history, patients don’t always provide specific information about their vision, but they report what they do for a living, what they do for fun and how they use their eyes on a day-to-day basis. We need to take that information and apply it to the objective clinical data we collect. The case history should be more than just a piece of paper we ask patients to fill out.
Dr. Basinger: I agree. Learning about the patient’s lifestyle is key.
Dr. Geffen: It’s crucial to ask open-ended questions. Patients may think we want quick yes or no answers when we really want to reveal what they’re truly thinking. I try to make sure everything I ask incorporates discussion versus a quick answer.
Dr. Quinn: Do we have any tools to make this information-gathering process efficient?
Dr. Epstein: Typically, the patient intake form contains lifestyle questions. However, some patients think they have a problem that can’t be addressed, so they don’t mention it. With that in mind, we ask additional questions, such as whether they’re having problems performing a specific activity.
Dr. Quinn: So the form is a place to start and then you follow up with a verbal discussion?
Dr. Marsden: Yes, the history goes on throughout the examination. As we are conversing with patients, topics arise that they may not have mentioned on their intake form. For example, if they say they’re going camping next week, we can ask what they do while they camp. I think, too, we should be careful not to focus too narrowly on hobbies. We want to find out how patients use their eyes every day of the week and in different situations that might not be represented by an eyechart at the end of an exam lane.
Dr. Geffen: We train our staff to ask questions during the pre-test exam and when taking patients to the exam rooms. They make brief notes on the exam chart, such as “patient works on a computer” or “patient’s hobby is X.”
Dr. Quinn: Do you train staff members to probe further in those areas?
Dr. Geffen: We have a list of questions for staff to ask during pre-testing. We train staff members on how to describe each test and direct them to ask additional questions based on information provided on the intake form. We plant seeds throughout the process about what vision-correction options are available to address certain needs.
RESEARCH REVEALS EYE-RELATED NEEDS
Dr. Vogt: The Needs, Symptoms, Incidence, Global Eye Health Trends (NSIGHT) Study provides a useful assessment of the needs and preferences of patients who require vision correction.1 (See “The NSIGHT Study.) NSIGHT provides a detailed look at patients’ eye and vision-related symptoms, which gives eyecare practitioners valuable clues about how to ensure patient satisfaction with vision care products and treatment decisions.
According to NSIGHT, glare and halos are among the symptoms most often experienced by patients who require vision correction. Globally, one third (34%) of the NSIGHT patients surveyed reported experiencing halos, while more than half (53%) reported experiencing glare. About 90% of patients reported having either no solution or one that was unsatisfactory or less than complete, but stated they wanted a solution for halos and glare (Figure 1). Among patients with astigmatism, 39% of respondents, a commonly reported symptom was blurry or hazy vision. In the astigmatic group, 46.5% of the patients experienced blurry or hazy vision, and 87% considered it bothersome.
Figure 1. In the NSIGHT Study, most vision-corrected patients who experience halos and glare reported that they would like to have a solution, presenting an opportunity for eyecare professionals to improve both vision and personal satisfaction for their patients.
Other studies contain similar findings. In one that specifically examined patients who wore toric contact lenses, 47% of subjects reported experiencing blurry or hazy vision, 37% reported fluctuating vision, 32% reported distorted vision and 32% reported glare and halos in low-light conditions. These studies may suggest that the attributes and performance of current toric lenses may be improved so more patients can achieve consistently crisp, clear vision throughout the day.2
|The NSIGHT Study|
|The Needs, Symptoms, Incidence, Global Eye Health Trends (NSIGHT) Study is an online survey of 3,800 vision-corrected patients, age 15-65, from seven different countries in three regions. Participants in the study, conducted by independent research firm Market Probe Europe with funding from Bausch + Lomb, include spectacle and contact lens wearers.|
NSIGHT gathered comprehensive baseline data on all respondents, including gender, age, social class, education, community type, occupational status, work environment, level of physical activity, type of vision disorder (Figure 1a) and method of correction. For contact lens wearers, data included lens type, when and how lenses are worn, replacement timing, brand and details of lens care solution used. The study explored two main areas:
Figure 1a. In the NSIGHT Study, 39% of patients reported having astigmatism.
■ Eye-related symptoms: NSIGHT surveyed respondents on 14 eye symptoms (halo, glare, fatigue, sensitivity, itching, dryness, eye strain, redness, puffiness or swelling, pain, headaches after near work, blurry or hazy vision, watery eyes and burning sensation). Respondents reported which symptoms they experienced, rated frequency and intensity, how they’re treated and with what degree of success.
■ Eye/vision care product needs: NSIGHT respondents reviewed a list of 40 potentially beneficial attributes of eye/vision care products (e.g., “provides vision that is as close to natural as possible” and “protects eyes in dry environments”). The survey respondents viewed the 40 product features in multiple groupings of six. For each grouping displayed, they ranked individual features as among the most or least compelling. The results allowed creation of a Hierarchy of Needs, a ranking from most to least compelling of the 40 individual features and the eight categories into which they can be grouped (vision, health, environment, eye condition, convenience, comfort, personal performance and personal appearance) (Figure 2a).
Figure 2a. In the NSIGHT Study, potentially beneficial product features related to vision consistently ranked as most compelling to patients.
The results of the NSIGHT Study are providing eyecare practitioners with new, and in some cases unexpected, insights into patients’ needs and preferences. The findings provide an evidence-based framework for discussing vision and eyecare treatment options.
Interestingly, a common thread across studies is the value patients place on quality vision. NSIGHT revealed that product features relating to vision quality are highly important to patients around the world. In the study’s analysis of 40 product features, six of the seven top-ranked features were related to vision, all with scores signifying high importance. In a hierarchy of eight major categories of product features, vision ranked highest and was the only category in the “highly important” range. Similarly, in another survey of 201 astigmatic contact lens wearers, the benefit of a soft toric contact lens considered to be of the highest relative importance was that the lens should “deliver consistently clear vision at all times.”2,3 Despite the numerous studies of patients, particularly astigmatic patients, expressing the importance of visual quality, a 2005 report indicated that only 21% of astigmatic patients are wearing soft toric contact lenses.4 And a report from 2008 indicated that 40% of astigmatic patients believe their astigmatism precludes them from wearing contact lenses, while 30% have not tried toric contact lenses due to advice from their eyecare practitioners, even though two out of three were highly motivated for a solution to better address their vision needs.5 Given all of these data, eyecare practitioners should expect that achieving the best vision possible is of paramount importance to their patients. From my point of view as an optical physicist at Bausch + Lomb, it’s my job to wonder why so many patients are suffering from uncorrected astigmatism and why so many are experiencing problems like glare and halos, and feeling as if there’s no solution.
Dr. Marsden: It’s because for decades, they’ve been hearing that the vision they had with spherical equivalent lenses was as good as it gets.
Dr. Vogt: Exactly, and patient surveys support that. Many patients have problems with vision because they’re frequently in settings where glare and halos are prevalent. For example, millions of us drive to work in the dark and sometimes home from work, as well. We have headlights coming toward us, which are a major source of glare and halos. When I try to explain glare or halo, I always mention the car headlight. People can relate to that.
Imperfections or optical aberrations in spherical ametropic or astigmatic eyes contribute to the visual symptoms we experience. Spherical aberration (Figures 2 and 3) contributes to glare and halos, and may degrade retinal image quality and may reduces contrast sensitivity and visual acuity.
Figure 2. With spherical aberration, light rays passing through the center and periphery of the optical system do not simultaneously focus at the same focal point.
Figure 3. Images of a Bailey-Lovie visual acuity chart taken with a portable eye-model camera to demonstrate retinal image quality with +0.15 µm spherical aberration (left image) or with 0.00 µm spherical aberration (right image). The chart imaged in the presence of +0.15 µm spherical aberration demonstrates reduced resolution, contrast and halos.
REDUCING SPHERICAL ABERRATION IMPROVES QUALITY OF VISION
Dr. Vogt: Non-aspheric lens designs inherently demonstrate spherical aberration due to their highly curved spherical surfaces; negative spherical aberration for negative power lenses, and positive spherical aberration for positive power lenses, in proportion to their back vertex power. Aspheric Bausch + Lomb contact lenses with High Definition Optics are designed to reduce both the inherent spherical aberration of the average human eye and to reduce the spherical aberration induced by the contact lens as it conforms to the shape of the cornea.
This is precisely what we at Bausch + Lomb have done with PureVision2 with High Definition (HD) Optics For Astigmatism. This new lens reduces spherical aberration similar to the PureVision2 HD lens, but unlike any other toric silicone hydrogel soft contact lens, it reduces spherical aberration in both the sphere and cylinder meridians.
Dr. Quinn: How much variation in positive spherical aberration is present in the population?
Dr. Vogt: Previous research has suggested a population average of about +0.15µm of spherical aberration.6 In a new study of more than 1,300 eyes (1,159 myopic and 174 hyperopic) from a more comprehensive population of subjects than earlier studies, the average amount of spherical aberration reported was +0.18µm for the myopic eyes and the age-matched hyperopic eyes.7 To design a contact lens that reduces the inherent spherical aberration of the eye as well as the spherical aberration induced by the contact lens, a thorough understanding of the physical properties of the contact lens materials as they conform to the corneal shape is necessary. The PureVision family of lens material, for example, is designed with – 0.15µm of spherical aberration in order to reduce the population average of +0.18µm spherical aberration. While there is a wide range of individual spherical aberration values across the patient population, 92% of patients have positive spherical aberration.8 By knowing the average amount of spherical aberration, we can benefit the greatest number of patients with the lens design.
VISION + COMFORT EQUALS WEARABILITY
Dr. Vogt: Furthermore, the PureVision2HD For Astigmatism not only reduces spherical aberration like no other silicone hydrogel toric lens currently on the market (Figure 4), but it also incorporates several other elements that make it a no-trade-off lens when it comes to patients’ vision and comfort. A great deal of research went into the development of all of the lens design elements. An understanding of eyelid blink mechanics, for example, led to Auto Align Design, a hybrid ballasting geometry with optimized thick and thin zones works with patients’ eyelids to provide excellent orientation for consistent vision. A large, 14.5-mm, lens diameter improves centration, which contributes to outstanding acuity. Auto Align Design also includes a large optic zone that helps deliver consistently clear vision in varied lighting conditions.
Figure 4. Spherical aberration for PureVision2 for Astigmatism compared to Biofinity Toric, Air Optix for Astigmatism and ACUVUE Oasys for Astigmatism.
Dr. Quinn: Does making the lens larger makes it more stable because it reduces the interaction between the lens and the eyelid?
Dr. Vogt: The larger diameter improves the stability by increasing the surface area of the lens, which provides a large optic zone as well as a larger area in which to optimally position the ballast.
The ComfortMoist Technology used in the PureVision2 HD For Astigmatism consists of two key features. First, the edges are rounded and thinner than on other torics, including the original PureVision Toric (Figures 5 and 6). This creates a gentler transition from lens to conjunctival tissue, allowing for a more natural feeling on the eye and enhancing all-day comfort. Secondly, the lenses come in a moisture-rich packaging solution, which fosters comfort upon insertion.
Figure 5. Images comparing the new thinner, rounded edge design of the PureVision2 HD For Astigmatism lens to PureVision Toric.
Figure 6. Images depicting the thin, rounded edge design of the PureVision2 HD For Astigmatism lens in comparison to competitor products.
Additionally, this new lens has fewer alignment markings than the original PureVision Toric, one instead of three, which helps to improve comfort. Overall, the three lens design attributes — HD Optics, Auto Align Design and ComfortMoist Technology — work together to provide exceptional lens performance. Feedback from eyecare practitioners and patients has been very positive. Practitioners agree 97% of the time that PureVision2 HD For Astigmatism delivers excellent stability and agree 89% of the time that the lenses deliver consistently clear vision.9 Eighty-three percent of patients rate overall comfort positively when wearing the lenses, and 71% of patients agree that they provide superior vision.9 CLS
Contact Lens Spectrum, Issue: March 2012, page(s): 4 - 7