Breathing, Patience and Keratoconus

7/1/14

Besides hearing from eye care professionals and Discovery Eye Foundation staff, we also think it is important to hear from people with sight threatening eye diseases such as age-related macular degeneration, keratoconus, retinitis pigmentosa, etc. They can share their experiences with others that are newly diagnosed with eye disease, while providing insights to family members, friends and caregivers. What follows is the first of these occasional posts focusing on the experiences and insights gained from vision loss.

“The expression on my optometrist’s face was as if he was giving me a cancer sentence,” Jeanette Hasseman remembers. “I had never heard of keratoconus, but he told me it was an incurable vision disability. He said he was aware of some evolving technology, but he wanted to give me some time to absorb and research the disease.
Jeanette Hasseman - keratoconus
“When I went back three months later, he told me a about a cross-linking study that was going on not-too-far from here, but I hadn’t fully absorbed all the information I was reading yet,” she recalls. I did not understand — even though it was plainly stated in the information I was looking at — that once you lose some vision, you don’t get it back.

“I kept thinking, ‘OK, this certainly can be fixed,” so instead of getting cross-linking in July, I waited until December. I regret not acting on my doctor’s suggestion of getting in the study in July, because I lost a tremendous amount of vision by December.”

Hasseman was tested and qualified for the clinical trial in December and had epi-on cross-linking in both eyes in January 2013. “The topography scans show the KC progression has been halted,” she says. “I rejoice in that.”

While her vision seemed better shortly after the procedures, she was diagnosed one week after crosslinking with a “gouge” (4 mm corneal abrasion) in her left cornea that resulted in severe hazing. While the severity of the corneal hazing has decreased in the past year, she is waiting to find out if it is permanent. If so, she may need to have a corneal transplant at some point to restore any visual acuity.

A registered nurse, Hasseman finished her BSN degree two years ago at age 54 — just months before she was diagnosed with KC. The native Ohioan has since stopped working as a nurse, and more recently, she had to give up teaching and doing tatting — lace-making — a hobby she had enjoyed for decades.

Hasseman found the National Keratoconus Foundation (NKCF) when she first Googled “kerotoconus.” “KC-Link has been a great blessing,” she says. “I’ve downloaded information; I signed up for KC-Link and asked questions of Catherine [Warren, director of NKCF] and the moderating doctors. I found great support for my own spirit, as well as information on the latest technologies.

“When people ask questions on KC-Link, if I can relate, I answer. Just the other day, someone who was just diagnosed asked, ‘Well, what should I do?’ I wrote: ‘First thing is: Breathe. Second thing is: Ask for information from your eye doctor and ask who is the best corneal specialist in your area who is really good for keratoconus. Most of all: Be patient.’

“It’s really hard to lose your vision. Even in your own heart, you can feel isolated. KC-Link gives you a body of other people who totally understand what you’re thinking, what you’re feeling, what frustrates you. There is so much advice you can get on KC-Link regarding contacts, how to keep eyes moist, how to handle low-light driving, what type of e-reader works best for people with keratoconus — you cannot exhaust the information that is shared; you cannot exhaust the different emotions that are shared.”

Jeanette HassemanJeanette Hasseman
Keratoconus Advocate

Corneal Donor’s Age Not Critical for Transplant Success

6/17/14

In the United States, more than 40,000 corneal transplants are performed each year with a high success rate in comparison to other types of organ transplants. According to the Eye Bank Association of America (EBAA), keratoconus was the leading cause of anterior lamellar keratoplasty (DALK/ALK partial thickness transplant) and was the fourth most common indication for penetrating keratoplasty surgery in 2012 (their last reporting period).
corneal transplant-original size
Advances in technology have led to increasingly successful outcomes for all who need corneal transplants. New long-term research of corneal transplant patients have shown that the age of corneal donors is no longer as important as once thought by eye health providers. According to a study funded by the National Institutes of Health, ten years after a transplant, a cornea from a 71-year-old donor is likely to remain as healthy as a cornea from a donor half that age.

The Cornea Donor Study (see www.ClinicalTrials.gov), funded by NIH’s National Eye Institute (NEI), was designed to compare graft survival rates for corneas from two donor age groups, aged 12-65 and aged 66-75. It was coordinated by the Jaeb Center for Health Research in Tampa, Fla., and involved 80 clinical sites across the United States. The study enrolled 1,090 people eligible for transplants, ages 40-80. Donor corneas were provided by 43 eye banks, and met the quality standards of the Eye Bank Association of America. The study found that 10-year success rates remained steady at 75 percent for corneal transplants from donors 34-71 years old. In the United States, three-fourths of cornea donors are within this age range, and one-third of donors are at the upper end of the range, from 61-70 years old.

Prior to this study, many surgeons would not accept corneas from donors over 65. Since the supply of young donor corneas is limited, these study results are encouraging for those who face a corneal transplant . The high level of success rates using corneas from older donors (over age 60) greatly increases the pool of donated corneas and corneal tissue available for transplant. In 2012, corneal donors under age 31 comprised less than 10 percent of the U.S. donor pool. “Our study supports continued expansion of the corneal donor pool beyond age 65,” said study co-chair Edward J. Holland, M.D., professor of ophthalmology at the University of Cincinnati and director of the Cornea Service at the Cincinnati Eye Institute. “We found that transplant success rates were similar across a broad range of donor ages.”

“Overall, the findings clearly demonstrate that most corneal transplants have remarkable longevity regardless of donor age,” said Mark Mannis, M.D., chair of ophthalmology at the University of California, Davis, and co-chair of the study. “The majority of patients continued to do well after 10 years, even those who received corneas from the oldest donors.”

SOURCE: National Eye Institute Press Releases

For information about Eye Bank Association of America

CathyW headshotCathy Warren, RN
Executive Director
National Keratoconus Foundation

New Technology for Evaluating Contact Lenses

5/1/14

Successful management with contact lenses can sometimes be a frustrating process for those with keratoconus. The fitting and evaluation process involves numerous visits to the optometrist, out of pocket expenses as well as medical insurance co-pays. Luckily, the contact lens industry has responded to the need to have better contact lens materials for patients with keratoconus. It used to be that the only contact lenses available to manage keratoconus were gas-permeable (GP) lenses. Now, more and more patients are being fit with newer generation hybrid lenses (GP lens core with a skirt of soft lens material to aid in fit and comfort) and scleral lenses (large diameter GP lenses that do not rest on the cornea, only the outlying sclera). These newer designs are intended to vault over the central cornea and do not rest on the cornea at all. They have resulted in much more comfortable and wearable strategies for full-time use. As a result of the newer lens designs, the game has changed when it comes to the science of fitting and evaluating the lenses.

For years, optometrists have used corneal topography to guide their decision making on fitting keratoconic eyes. A corneal topographer is an instrument that maps the shape of the cornea, and gives information much like that of a topographical map for hiking. Corneal topography is still an absolutely mandatory part of evaluating the shape of the cone, the simulated corneal curvature, and monitoring for progression of the disease, and is not a standard part of a typical eye examination. However, doctors have a new tool at their disposal for fitting contact lenses on patients with keratoconus.

Optical Coherence Tomography (OCT) was once reserved for use in the back of the eye, or retina. OCT uses visible light passed through the clear structures of the eye to generate a cross-sectional image of the layers of the retina, much like an image generated by an MRI. Advances in OCT technology has improved the resolution to image the eye on the micrometer scale (one-thousandth of a millimeter). OCT technology is now commercially available not only for the retina, but the structures of the front part of the eye. The obvious application is to aid the doctor in the fitting and evaluating complex contact lenses that vault the cornea.

Figure 1. OCT image of a scleral lens fit on a keratoconic patient. The cornea is the opaque white band located at the bottom of this picture, the tear film reservoir is the middle clear band and the contact lens is the top band. Using an electronic caliper tool, the precise amount of vault can be measured, leaving no doubt as to the precision of the fit.
Figure 1. OCT image of a scleral lens fit on a keratoconic patient. The cornea is the opaque white band located at the bottom of this picture, the tear film reservoir is the middle clear band and the contact lens is the top band. Using an electronic caliper tool, the precise amount of vault can be measured, leaving no doubt as to the precision of the fit.

OCT allows the optometrist to view a cross-sectional image of the contact lens on the eye in real time and to monitor the health of the cornea in the presence of the contact lens. This view is valuable for judging the vault of new designs of contact lenses over the cornea and judging where the lenses land on the eye. It is the most specific way to determine if the fit is acceptable and to troubleshoot if lenses are not fitting appropriately.

Figure 2. OCT image of the periphery of a scleral lens on a patient with pellucid marginal degeneration. The lens contacts the cornea over an area of 0.87mm long. These types of measurements help guide decision making in modifying the lens fit and were impossible before the advent of this technology.
Figure 2. OCT image of the periphery of a scleral lens on a patient with pellucid marginal degeneration. The lens contacts the cornea over an area of 0.87mm long. These types of measurements help guide decision making in modifying the lens fit and were impossible before the advent of this technology.
Figure 3. Hybrid lens on a highly irregular eye after corneal transplant. The point of contact of the soft skirt with the cornea is visible to the right of the image.
Figure 3. Hybrid lens on a highly irregular eye after corneal transplant. The point of contact of the soft skirt with the cornea is visible to the right of the image.

Optometrists now have a much more powerful tool for evaluating and managing even the most challenging contact lens fits. It remains to be seen whether this technology has the ability to reduce the number of visits required for successful fit. But, the precision afforded by this technology does have the ability to improve patient outcomes.

Sonsino HeadshotJeffrey Sonsino, OD, FAAO
The Contact Lens Center at Optique Diplomate
Cornea, Contact Lens, and Refractive Therapies

The “A B C’s” of Contact Lens Fitting for Keratoconus

4/18/14


Keratoconus is a disease of the cornea in which the cornea loses its natural round shape and becomes distorted with cone-like bulging, progressive thinning, and associated reduction in vision quality. It is the front surface of the cornea that is the most significant focusing element of the eye. The irregularity of the front surface of the cornea in keratoconus is primarily responsible for the poor vision obtained with glasses since light that is focused through glasses lenses once again passes through air prior to reaching the corneal surface where again it is distorted. Contact lenses utilized for vision correction in keratoconus serve to “mask” the irregularity of the corneal surface thus creating a new smooth and regular front surface to the optical system.

Today contact lens correction for keratoconus is NOT synonymous with rigid corneal lenses. There are numerous options available to the contact lens specialist that can provide significant vision improvement for patients with keratoconus. It is the responsibility of the contact lens specialist to determine which design of contact lens is most appropriate for the individual patient. Let’s review the various options available today for the contact lens management of keratoconus.

Corneal rigid gas permeable contact lenses have been the mainstay for contact lens correction of keratoconus for many decades.

Large diameter corneal gas permeable lens fit with clearance of the cone apex. - contact lens
Large diameter corneal gas permeable lens fit with clearance of the cone apex.

These are made of oxygen permeable rigid materials and are typically of a size that is smaller than the overall corneal diameter and they are fit to center as well as possible over the optical center of the cornea. Due to their rigid nature they do a wonderful job in masking the corneal irregularity and provide excellent vision. However, certain limitations have required us to develop other contact lens options for keratoconus. The limitations include; difficult initial adaptation and ongoing comfort issues for some patients, difficulty in centering over the optics of the eye in cases of more advanced and decentered cones, and occasional cases where lenses are not stable on the cornea and will dislocate. Most importantly, corneal rigid lenses that are fit “flat” and bear on the apex of the cone may induce progressive corneal scaring over time. Current fitting philosophy for these lenses attempts to fit with clearance over the cone apex.

Soft contact lenses have a significant role in the treatment of keratoconus. Mild and early cases can be managed with traditional non-specialty soft contact lenses as long as the degree of corneal distortion is not too severe.

Custom specialty soft lens for keratoconus with thick central optical zone and thin periphery. Courtesy of Visionary Optics. - contact lens
Custom specialty soft lens for keratoconus with thick central optical zone and thin periphery. Courtesy of Visionary Optics.

Typically soft astigmatism correcting contact lenses are required. More advanced cases can be treated with specialty keratoconic designed soft lenses. These lenses typically have the central optic zone thickened in order to mask the corneal irregularity. However, the periphery of these lenses is thinned and provides excellent comfort and eye health response, especially when designed with highly oxygen permeable materials. We have been able to manage many cases of moderate and somewhat severe keratoconus with these specialty lenses. The advantage primarily is in lens wearing comfort and positional stability on the corneal surface. The limitation is typically if these lenses can provide adequate vision correction for the individual.

Piggyback or tandem lens systems utilize a combination of rigid corneal gas permeable lenses and soft lenses. Typically we utilize a thin, highly oxygen permeable soft disposable lens with insignificant power and then fit an appropriate gas permeable rigid lens on top of the soft disposable lens. The rigid lens provides the vision correction and the soft lens provides superior comfort compared to the rigid lens being fit directly on the eye surface and also occasionally helps with centration of the rigid lens over the optics.

Recessed Pillow Lens System (RPLS). Courtesy of EyeVis Eye and Vision Technologies and Fusion Technologies.- contact lens
Recessed Pillow Lens System (RPLS). Courtesy of EyeVis Eye and Vision Technologies and Fusion Technologies.

A variant of this system is called a “recessed pillow lens system” (RPLS) where a custom soft lens is created with a partial thickness cut out or recess that can hold a rigid lens in place. This can be used when a typical piggyback/tandem system cannot allow the rigid lens to center properly.

Hybrid contact lenses are available in specialty designs to address keratoconus. A hybrid lens is constructed with a rigid gas permeable lens center and a soft lens “skirt”. Again, the rigid lens provides the vision correction and the soft skirt provides excellent lens centration and improved comfort. Limitations of hybrid lenses include the inability to fit on more advanced and decentered cones and their potential to tighten up on the eye making removal more challenging and potential for eye irritation. However, new designs and fitting methods have addressed these issues in most cases.

Finally, scleral lenses are an excellent option for keratoconus. These are large diameter rigid gas permeable lenses. They vault the entire cornea and do not touch the corneal surface at all.

Fully customized scleral lens design based on an “Eye Print” impression. Courtesy of EyePrint Prosthetics.- contact lens
Fully customized scleral lens design based on an “Eye Print” impression. Courtesy of EyePrint Prosthetics.

A tear layer is created below the scleral lens and the lens comes to rest gently on the white of the eye (the scleral surface). This results in very good lens comfort and it also protects the corneal surface from the negative effects of contact lens bearing. The rigid material provides excellent optics. Limitations of scleral lenses include the complexity of fitting, difficulty in insertion and removal on occasion and entrapment of mucous and debris below the lens requiring removal and rinsing of the lens for some patients. Overall scleral lens fitting is taking a larger role for keratoconus over the past few years. We are now developing totally customized scleral lens systems based on taking scans or impressions of the ocular surface to design a totally customized lens made uniquely for the individual eye that can address even the most distorted ocular surface.

Today we have multiple contact lens options to address the vision needs of our keratoconic patients. It is the responsibility of the contact lens practitioner to prescribe the most appropriate design for the individual patient.

Barry Eiden OD, FAAOS. Barry Eiden, OD, FAAO
North Suburban Vision Consultants, Ltd., President and Medical Director
www.nsvc.com
National Keratoconus Institute, President and Medical Director
www.nkci.org
EyeVis Eye and Vision Research Institute
sbeiden@nsvc.com

Wavefront Sensing Applied to Custom Contact Lens Research in Keratoconus

4/10/14

During a trip to the optometrist or ophthalmologist, a patient will encounter the process of subjective refraction.  This technique involves the clinician asking the patient to make a series of judgments (which is better, one or two?) about the clarity of their vision when looking through a series of lenses.  The choices that the patient makes guide the clinician in identifying an optical prescription which is typically made up of sphere, and potentially, cylinder lenses.

Why is it that glasses don’t always work for patients with keratoconus?

In many instances, individuals with keratoconus do not achieve excellent visual performance with spectacles or traditional soft contact lenses.  One cause for the failure of these corrections is that the changes in corneal shape that accompany keratoconus induce refractive errors which traditional spectacles simply cannot correct.  So, even when sphere and cylinder in the keratoconic eye are well-corrected, these “other refractive errors” or “other aberrations” remain uncorrected and can lead to a blurred retinal image and blurred vision.  Collectively these other aberrations can be referred to as higher order aberration, while the aberrations that are typically corrected with spectacles and soft contact lenses are referred to as lower order aberration.

What kinds of higher order aberrations are present in keratoconus:

Pantanelli et al. have stated that the level of higher order aberration present in an eye with keratoconus is, on average, approximately 5.5 times higher than the level experienced in a control group.  In an effort to visualize higher-order aberration data, they are commonly represented graphically as shown in the figures below.  Examples of higher order aberration measured in one normal eye are shown in figure A, while an example of higher order aberration from one keratoconic eye are shown in figure B.  The circular nature of the map denotes the boundary of the measurement, which is defined by the round pupil of the eye.  A majority of the higher order aberration map in figure A is green (denoting a relative absence of higher order aberration).  However, the map in figure B displays a much larger variation in color, indicating the presence of higher order aberration  in this individual keratoconic eye in a greater quantity than the normal eye shown in figure A.

Figure A - normal-keratoconus
Figure A – normal
Figure B - keratoconus
Figure B – keratoconus

A wavefront aberration map of the “other aberrations” or higher order aberrations of two eyes. Figure A is an example of data for a normal eye and figure B is an example of data for an eye with keratoconus.

If refraction is not capable of quantifying higher order aberrations, how are they measured?

One method for obtaining the information regarding higher order aberration shown above is with a wavefront sensor.  The wavefront sensor objectively (without patient feedback) collects information on the optical performance of the eye that can be used to calculate the amount of both lower and higher order aberration present.

Laboratory-based research related to custom contact lenses:

Several investigators in the laboratory (e.g. Katsoulos et al., Sabesan et al., Chen et al., Marsack et al.) have reported on work that attempts to further reduce higher order aberration by targeting the eye-specific higher order aberration seen in a given keratoconic eye.  The general philosophy behind these customized lenses is that the aberration pattern measured with the wavefront sensor is a more complete optical prescription for implementation of a custom contact lens.  Figure C demonstrates, in principle, the optical properties of a contact lens designed to correct the higher-order aberration in figure B.  Where the map of the eye (figure B) is red, the map of the correction (figure C) is blue, and vice versa.  When the lens is worn, the net effect as light propagates through the lens-eye system is the cancellation of the higher order aberration in a targeted manner.

Figure C -keratoconus correction
Figure C -keratoconus correction

In principle, this figure pictorially represents the higher order optical properties of a contact lens designed to fully correct the higher-order aberration of the eye represented in figure B.

What is next:

Investigators continue to push the technology behind custom contact lenses for keratoconus towards clinical relevance.  However, like every novel intervention strategy, we must manage our expectations.  Complexity in measuring keratoconic eyes, a need for specialized equipment and expertise to design and manufacture the lenses, the infrastructure needed to coordinate the clinical exam and manufacture efforts and cost associated with the process are a subset of the barriers that must be removed if this type of correction is to become more mainstream.  For this reason, it is my opinion that if/when these corrections become commonly available in the clinic, they will likely add to, and not replace, existing forms of corrections that patients and clinicians now utilize to correct vision.

jmarsack-bio-picJason Marsack, PhD
Research Assistant Professor
University of Houston, College of Optometry.
Dr. Marsack’s work focuses on the relationship between visual performance
and optical aberration in individuals with highly aberrated eyes.

Help for Computer Users

Working long hours in front of the computer requires a fairly unchanging body, head and eye position which can cause discomfort.  Correct working position, periodic stretch breaks, frequent eye blinking, artificial tears for lubrication are all very important.  However, it’s not always easy to remember this when you are engrossed in work. Here are a few fun, free and easy-to-install “break reminders” to help:

WorkSafe Sam - break reminder
WorkSafe Sam
WorkSafe Sam is a desktop tool that provides stretching tips to help reduce eye and muscle strain for office workers (clicking on this link will open a file on your computer because this is a zip file).

Workrave is break reminder program that alerts you to take “micro-pauses” and stretch breaks.

Take Your Break is another break reminder designed to prevent or minimize repetitive strain injury, computer eye strain and other computer related health problems.  It has a friendly interface and a tray icon status indicator.  It runs quietly in the background, monitoring your activity and reminding you to take regular breaks.

And remember to blink.  Blinking cleans the ocular surface of debris and flushes fresh tears over the ocular surface. Each blink brings nutrients to the eye surface structures keeping them healthy. The flow of tears is responsible for wetting the lower third of the cornea. This is very important in KC, since this area is generally below the bulge of the cone and in many cases irritated by wobbly RGP lenses.  Maybe your job requires hours of work at a computer. Maybe you like to spend your free time surfing the internet. Whatever the reason, your body is probably feeling the effects of spending too much time staring at a computer monitor, which could result in Computer Vision Syndrome (CVS).  The most common symptoms are: eye strain, dry or irritated eyes,redness in eyes,difficulty in refocusing eye,neck pain,double vision,blurred vision, fatigue, and headaches.

Please join us on Thursday when Dr. Bezalel Schendowich will be providing a detailed insight into the importance of blinking, going beyond computer usage.

CathyW headshotCathy Warren, RN
Executive Director
National Keratoconus Foundation

Corneal Transplant Surgery Options

In this day and age of advancing technology, corneal transplants have changed from a long arduous ordeal to a more simple and precise procedure that offers faster visual recovery.  Instead of replacing the entire cornea for any and all corneal diseases, we now perform disease targeted partial corneal transplants.  If the disease involves the back layer of the cornea, we perform endothelial keratoplasty and replace only the diseased inner layer of the cornea.  Conversely, if the problematic portions are the front layers of the cornea, we perform anterior lamellar keratoplasty.  The co-morbidity and risk of rejection from partial corneal transplants are significantly less than the traditional full thickness transplants.

With endothelial keratoplasty, a small incision, about 4-5 mm is made and a sheet of donor endothelial cells are placed into the anterior chamber of the eye.  A large air bubble is then used to float this sheet up so that it opposes the posterior or back portion of the cornea.  The patient is asked to position face up for 24 hours.  Over this period of time, the cells will “stick” on their own and thus no sutures are required to keep the graft in place.,/span>

Figure 1 - corneal transplant
Figure 1

Anterior lamellar keratoplasty is done for superficial scars and opacities of the cornea or for keratoconus, a genetic degeneration of the cornea that is seen in younger individuals.  In this case, the native endothelial cells of the patient are healthy and therefore are left intact while the remainder of the cornea is transplanted.  This significantly lowers the risk of rejection, which is traditionally a much higher risk in young patients.  Multiple sutures are required to maintain this graft in place however, with the advent of femtosecond laser technology, the wound configuration is made in such a way as to promote rapid healing and visual recovery. (Figure 1)  Sutures are removed at an earlier time than with traditional surgery and the eye is able to undergo visual rehabilitation with glasses or contact lenses in 3-6 months’ time.

Corneal transplantation does not require waiting on a list for a donor to become available like it once did.  There are now multiple excellent eye banks across America that harvest, screen, and distribute donor tissue to surgeons.  This way, tissue is readily available and patients only need to schedule a time based on their own and their surgeon’s time schedule.  Post operatively, patients are asked to return to regular activity with the exception of no heavy lifting or bending for a period of 2 months.  Antibiotic and anti-rejection drops are started immediately after surgery and continued for several months after.  No oral medications aside from the patient’s regular medications are required.

Farid 3.6.14Marjan Farid, MD
Director of Cornea, Cataract, and Refractive Surgery
Vice-Chair of Ophthalmic Faculty
Director of the Cornea Fellowship Program
Associate Professor of Ophthalmology
Gavin Herbert Eye Institute, University of California, Irvine