2008 Hoya Grant & Scholarship Wining Case Study

Transcription

1 2008 Hoya Grant & Scholarship Wining Case Study Progressive Lens Technology and the Implications for Struggling Presbyopes with Peripheral Distortion and Blur: A Case Study Andrew M. Graves 3 rd Year Optometry Student School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294

2 Abstract Background: Presbyopia is one of the most common refractive conditions of any patient over the age of 45. As our clientele reach this age, the need for new and better ideas for correcting this condition are required both for the benefit of our patient s vision as well as our growing practices. The clinical manifestations of presbyopia revolve around the need for extra lenticular power at intermediate and near distances due to the patient s decreased ability to accommodate as brought on by aging. These patients are typically noticing a loss of visual capacity while working at a our lifestyles are becoming more focused on computer w uter or attempting to read. As this disadvantage exhibits a large detriment to our faithful presbyopic patient s quality of life. Case Report: In the study reported here, a 58 year old Caucasian female presented to our clinic with reduced visual acuity at distance and near OU. After an evaluation of refractive complaints and ocular health, the patient was diagnosed with simple hyperopia and presbyopia. Although a simple case diagnostically, the visual complaints addressed were indeed more complex due to the patient s specific symptoms. The focus of this case study seeks to correlate the advantages of novel technology in progressive lens design and the resolution of pre-existing visual symptoms of an absolute presbyope. Conclusions: As most clinicians are readily aware, a thorough case history is vital in the successful diagnosis and treatment options for patients with specific and long lasting visual complaints. It is of the utmost importance for clinicians to keep current with the latest technological innovation; not only in the treatment of disease, but also the manufacture and design of lens technology.

3 Introduction: Over this decade and the next, the baby-boomer generation will reach the age where their accommodative capacity continually diminishes and the need for additional help at near will drive them into our offices. In many cases, these problems may be easily corrected with small changes in near power in the prescription and/or adjustment to the frames. In general, clinical approaches in the correction of patient s presbyopic complaints have not often lead to the incorporation of a new lens design or technology. Instead, for most cases of this nature, the case history leads to the conclusion of simply a change in powers. According to the United States Census Bureau, the nation s population over the age of 55 has steadily increased to 22.6% of the total population. With this information is can be inferred that the vast majority of our patients are or will be presbyopic in the near future. (1) It should also be noted that there is rising interest regarding the visual advantages and improved cosmesis that progressive lenses provide. As seen clinically, this interest has grown tremendously with new innovations beginning in the 1980 s and extending to present day. An important aspect to be considered is that there are a significant number of patients currently using progressive lenses. However, technology has left many of our patients behind and the lens designs worn by many of our faithful patients are outdated and leave much to be desired in visual performance. Although many of our current progressive lens designs are more cosmetically pleasing than the typical bifocals, the technological advances that address chromatic aberrations and increase the usable field of view have fallen behind the times until recently.

4 The latest progressive lens technology that has been introduced by Hoya has shown considerable promise and is scientifically proven to aid in correcting existing problems associated with current progressive lens issues. In particular, the Hoyalux id lens that was employed in this study is the world s first innovation of double-surface progressive design. (2) As described later in this text, the Hoyalux id lens uses patented technology in the surfacing and finishing to reduce these optical aberrations and distortions. By separating the horizontal and vertical components of power and integrating them into the front and back surfaces respectively, this adequately addresses the issues of spectacle aberrations. Hoya also incorporates revolutionary computerized technology that helps eliminate skew deformation and balances the view throughout the lens to aid in equilibrium. The goal of this design was to provide a lens that would successfully reduce distortions and aberrations that are prevalent with the previous progressive lens technology. Case Report: A 58 year old Caucasian female presented to the University of Alabama at Birmingham School of Optometry in Birmingham, Alabama for an eye exam in November of The patient s chief complaint was blurry and distorted vision at distance and near while wearing correction. Epiphora was also present in both eyes possibly as a result of eye strain. The patient had no complaints of pain, photophobia, redness, itching, or any other symptom of ocular health involvement. The patient s previous ocular history was relatively unremarkable in terms of her refractive error. She had no astigmatism and presented as a simple hyperope/presbyope in both eyes. Her complaints were very

5 specific with a notation about the discomfort of her progressive lenses. She provided a very detailed history with her complaints as she was an educated woman with some knowledge of her condition. As described by the patient, she noted a distortion or swim in the peripheral portion of her lenses in all fields of gaze. This complaint was so severe that it caused discomfort with prolonged use of her progressive lenses. The patient described annoyances with distance, intermediate, and near tasks, and at some points even nausea or dizziness. Although the focus of this case study was to determine how the change in lens technology would affect all her viewing distances, the near vision tasks remained her most prominent complaint. Her correctable acuities were 20/20 in both eyes and all other ocular health issues were within normal limits. All of her medical history was unremarkable and revealed no bearing to her current refractive complaints. Of particular interest was the fact that her peripheral swim, although nauseating at times, could be controlled and accepted through simple breaks in visual tasks. Although she had become acclimated to her strict regimen of glasses removal and discontinued near work, she was quite enthusiastic to attempt anything that we could offer that could correct this problem. was four years old. At the time of the patient s visit, her progressive lens technology In late 2007, the patient s choices for newer progressive lens technology were markedly more abundant and advanced. The patient s final refraction was DS OU with a DS add power for near. With the new options of an advanced technology progressive, the treatment of choice that was employed was the new Hoyalux id lens. This lens theoretically would provide the

6 patient with substantial enhancement of increased peripheral vision that was distortion free and allow her considerably more comfort for near tasks. The patient s glasses were provided in early December, 2007 and contact with the patient was maintained over the course of three months (December through March, 2007). The patient s new prescription was stronger in the distance and weaker at near, which gave a longer than usual adjustment period. Although this was anticipated her inal results showed marked improvement in her presenting symptoms. At the end of her follow-up appointments, the patient was pleased to report very little distortion along the periphery and improved ability to enjoy long periods of near activities. In the course of her follow-up, we performed a series of three measurements to determine the amount of clarity offered from the new lenses in comparison with her old lenses. This was performed utilizing the principles of the well-known tangent screen with an emphasis on the distance to the targets and peripheral clarity instead of simple visual fields and the detection of a stimulus. For this measurement, we used optical infinity for our distance vision, 64 cm for the intermediate vision, and 40 cm for our near vision measurements. Baseline measurements were recorded, noting the distance between clear intervals as direct comparisons between the old progressive and new progressive lenses. These differences were quantified and data provided as the percentage increase in peripheral clarity. The patient s base measurements are provided in Table 1 and graphically represented in Figure 1 to demonstrate the enhanced peripheral viewing capacity afforded by the Hoya lenses.

7 Table 1. Comparisons of old versus new (HOYA) progressive lens technology as measured by distance, intermediate, and near vision. Vision Old New % Increase in Lenses (cm) Lenses (cm) Peripheral Clarity Distance 80.5 ± ± ± 4.5 Intermediate 29.2 ± ± ± 3.9 Near 16.5 ± ± ± 3.9 Data obtained by measuring distance between peripheral blur at all three horizontal viewing planes. Percentage was determined as (distance (new lens) distance (old lens)/ distance (old lens). Figure 1. This graph is a visual representation of the measurements comparing the old lenses to the new lenses. It is clear from these percentages that the Hoyalux id lens is far superior in peripheral clarity then the conventional progressive from her habitual prescription. As shown in Figure 1, the Hoyalux id lens is far superior to the older progressive lens technology. The viewing range of this lens has more than doubled the patient s peripheral clarity. Upon completion of the follow-up period, the patient was thoroughly impressed with the improvements in correcting the patient s symptoms and the overall clarity of the lenses. In the most recent patient interview at month three, the patient had no complaints of ocular pain, blurriness, peripheral distortion, or nausea. The patient s continued wear time has improved her acceptance of the new lenses. We will continue to follow this

8 patient on an annual basis for her long-term ocular health and satisfaction with the Hoyalux id progressive lens design. Discussion: The incidence of presbyopia will continue to rise over the next several decades due to the increasing population of patients reaching middle-age. This condition results from a multifaceted range of age-related changes. It has been difficult to exactly pinpoint a sole reason for the occurrence of presbyopia; however, a multitude of theories exist. As the human body ages, the lens increases in size and the zonular fibers lose their elasticity which can decrease the ability for one to accommodate. (3) Even so, presbyopia is still a very treatable condition with many options currently available for our patients including spectacle corrections and contact lenses. In the case presented here, the treatment decision arose from the symptoms presenting on the patient s initial visit. To understand the reasoning behind choosing this specific lens, it was pertinent to recognize the concepts behind its manufacture and inherent technological advancements. The Hoyalux id lens was marketed as a revolutionary breakthrough in progressive lens design. This lens is specifically suited to patients who have sympt s of progressive lens discomfort due to distortion, peripheral swim, and equilibrium issues relating to the glasses themselves. As practicing optometrists, we can break down the treatment options for correction of the visual pathway through three actions. Perceptions of the image through the glasses serve as the initial step where we view an actual object. This shows where in space we are

9 viewing. The second step is interpretation of the object as seen through the applied correction which shows what we are viewing. The final step is image processing, which occurs at the cortical level and feeds into our sense equilibrium. At any point during these three steps, the patient can experience instability as a result of distortion or swim caused by many of the current progressive lens designs. This can mistakenly lead to false information processing and unsteadiness. The main reason for choosing the hoyalux id was its design characteristics, which accounted for these instabilities of our visual system. The images sent through these lenses would be perceived, interpreted, and processed by the eyes and the brain with little to no distortion in the patient s range of viewing providing a firm sense of balance and equilibrium. The Hoyalux id was designed to minimize the problematic issues inherent to progressive lenses. The advantages of this lens over other types of progressive lens are inherent due to the design characteristics. By virtue of placing the horizontal progressive component on the back surface and the vertical progressive component on the front surface, this lens widens the distortion free field of view while allowing for more eye rotation versus head movement. (2) Hence, the Hoyalux id lens represents the first integrated double-surface progressive lens. Hoya has developed two new technological advances in addition to its unique design. The first is called Skew Deformation Index Mapping and as the name implies, is used to evaluate distortion or skew deformation. Upon recalculation with this program, the design of the lens may be altered to reduce undesirable quality of existing progressive lens designs. The second technology used in this manufacturing process is Balanced View Control. (2) One of the most common complaints of many progressive lens

10 wearers is that of unstable or unequal movement of a scene and the subsequent effect with regard to the patient s balance and equilibrium. This additional procedure can calculate the distortion present and many angles around the lens thus creating a larger field of clear vision. All of these advanced design characteristics were factored into the patient s complaint and ultimately was the fundamental driving force behind choosing this lens for our patient. Conclusions: As presbyopia will become more prominent in our clinical experience due to our rising population of older patients, I believe it is important to understand the fundamental concepts underlying this case. The particular case study presented here demonstrates how an average and simple diagnosis of presbyopia can e on a more complex but ultimately enhanced resolution of the patient s primary complaint and visual health. The patient s thorough case history and familiarity with progressive lens use was pivotal in our decision for choosing the Hoyalux id lens. As described earlier, many patients utilizing older progressive lens technologies are not pleased with their current visual abilities. It is important for us as clinicians to realize that new technologies are available that greatly improve visual acuity and reduce many of problems that are associated with the use of progressive lenses. Although there is no cure for presbyopia, as long as our patients continue to age, we will be in the business of correcting this issue, and it is our responsibility to provide the patient with the best possible solution to correct their visual problems. To accomplish this goal, a thorough history and simple questioning of

11 annoyances can possibly give our patients a new outlook on their personal visual outcomes. In the case study presented here, by simply changing the patient s lenses to the newer and more technologically advanced Hoyalux id design, she was able to increase her peripheral visual clarity by approximately 70% over that of her previous progressive lens prescription. The treatment options presented in this case study reveal an inherent need to question these types of patients extensively about their symptoms and increasingly update our expertise in the area of progressive lens design. This will allow us to offer our patients the cutting-edge of lens technology. This alone could vastly improve or even fully correct these specific types of peripheral clarity issues arising from older design and manufacturing guidelines for the last generation of progressive lenses..

12 Bibliography 1. U.S. Census Bureau, Current Population Survey, Annual Social and Economic Supplement, 2006.). 2. Hoya Corporation, Hoya Vision Care, North America. (n.d.) Oyster, C. W. (1999). The Human Eye, Structure and Function. Sunderland: Sinauer Associates, Inc.