BRONSTEIN SEMINAR REPORT
A Report on the 33rd Annual Invitational Bronstein Seminar
Highlights from this long-standing contact lens educational meeting.
By Barbara Anan Kogan, OD
Dr. Anan Kogan specialized in toric, bifocal and orthokeratology GP designs in her Washington, D.C. practice. She has lectured nationally about contact lenses, was a contact lens clinical investigator and has authored, edited and collaborated on numerous contact lens articles.
Dr. Leonard Bronstein was one of the early pioneers in the contact lens industry, codeveloping a fused bifocal, reverse centrad bifocal and trifocal lens designs, and he was part of the first GP contact lens development team. An early aspheric lens design for keratoconus and irregular corneas was another of Dr. Bronstein's inventions. His instrumentation designs and patents included the binocular microspherometer as the radiuscope's forerunner as well as the corneoscope for designing contact lenses.
In 1973, the Bronstein Contact Lens Seminar began as invitation work sessions upstairs at Dr. Bronstein's Phoenix laboratory and office where he instructed practitioners in the fitting and design of rigid contact lenses. It has grown into one of the largest contact lens-only meetings in the United States.
This article will discuss highlights from the 33rd Annual Invitational Bronstein Seminar, which took place earlier this year in Scottsdale, Ariz.
Longtime Practitioners Honored
The third-annual Bronstein Awards Dinner honored contact lens legends Robert Mandell, OD, PhD, and Charles May, OD. Nearly every optometry student in America is introduced to Dr. Mandell's work when learning about contact lenses with each of the many updated editions of his Contact Lens Practice textbook. Today, many practitioners still refer to his "big red book" in their offices for how to design the best lens for each patient as well as for information on follow-up management and patient education.
At the Awards Dinner, Emcee Tom Quinn, OD, MS, said of Dr. Mandell: "He introduced many principles for fitting contact lenses with over 150 original papers. For 32 years Dr. Mandell taught and performed groundbreaking research. Additionally, he had a profound effect on what we know about contact lens design and fitting, pachymetry, corneal topography, the cornea and its response to contact lens wear."
Dr. Mandell has been awarded five contact lens patents since 2002, including his newest bifocal — the Mandell Seamless. This now retired educator/inventor/researcher also received seven major U.S. Public Health Service grants.
Dr. May, who has spent more than 60 years pursuing the art and science of contact lenses, is also the only optometrist who has authored a text on orthokeratology. Newton Wesley, OD's National Eye Research Foundation bestowed on Dr. May the title and honor of the "Grandfather of Orthokeratology." Responsible for many contact lens innovations and advancements, "Dr. May's GP design techniques and instruments for manufacturing and modification are still used today," said Dr. Quinn.
In the 1960s, Dr. May and Dr. Stuart Grant developed the basic orthokeratology concepts that resulted in the "May-Grant" fitting philosophy. This was the precursor of today's accelerated corneal reshaping lens designs (Paragon's Corneal Refractive Therapy, Bausch & Lomb's Vision Shaping Treatment, etc.). He also developed the corneaplasty procedure in which changes created by an orthokeratology lens design could potentially remain permanent through the use of corneal softening and rigidity agents.
Back to GP Basics
Dr. Quinn presented a seminar pertaining to keys to contact lens comfort. Because lens-associated discomfort is the leading cause of contact lens dropout, Dr. Quinn highlighted ways to enhance lens comfort and, ultimately, wearing success. His fitting basics begin with lens movement and centration. Sodium fluorescein evaluation of the lens-to-cornea relationship helps you determine how to manipulate the lens to control both movement and centration. The Fluorescein Pattern Identification Card from the CLMA's Gas Permeable Lens Institute (www.gpli.info) can help with making lens design changes, offering fitting pearls and 14 on-eye examples.
Contact Lens legend Dr. Robert Mandell was honored at this year's awards dinner.
GP Design Dr. Quinn suggested to first choose the overall diameter and order the lens larger to achieve an upper lid attachment, still known as the Korb fit from GP inventor/researcher Donald Korb, OD. During a blink, this fitting relationship will reduce any subjective awareness resulting from the lid interaction with the edge. It also stabilizes the lens along the line of sight, enhances vision and promotes lens movement even with a partial blink, enhancing corneal physiology.
According to Dr. Quinn, practitioners should observe the relationship between the upper eyelid and the upper limbus. If the upper eyelid covers the upper limbus, choose a larger diameter, such as 9.6mm, to achieve a lid attachment fit. If the upper eyelid rests above the upper limbus, choose a diameter such as 9.0mm, which will rest within the aperture. Consider lens diameter when selecting the base curve. A large diameter lens needs a flatter base curve to avoid excessive vaulting over the cornea (Table 1). A lid attachment fitting relationship is likely to result in patient satisfaction and success.
GP material options include silicone acrylate and fluorosilicone acrylate (FSA). Dr. Mandell has found that FSA materials have more resistance to protein deposits on the contact lens versus the earlier silicone acrylate material, thus improving comfort.
Diagnostic Fitting Dr. Quinn recommended the "No Surprise Approach" of Ed Bennett, OD, MSEd, executive director of the GPLI, for diagnostic evaluation of first-time GP contact lens wearers by instilling one drop of anesthetic prior to applying the GP. He advises this same procedure at the contact lens application and removal session and prior to dispensing a GP contact lens.
Plasma treatment of the lens surface can enhance the wettability of a GP and keeps the lens surface clean. Many CLMA member laboratories now offer the option of having the surface of newly fabricated lenses plasma treated to enhance wettability and comfort. It's important to use non-abrasive cleaners, such as Boston Simplus (Bausch & Lomb) and Lobob Laboratories' Optimum Care system, on plasma-treated lenses to prolong the benefits.
CLMA member laboratory consultants can suggest which care system works best with each GP material. Ensure that each patient continues to use this modality for continued comfort, good vision and lens longevity. Optimum Care is advised with many newer GP materials. Table 2 discusses recommendations for clear and safe lens wear for all contact lens wearers.
Assessing Dryness in GP Wearers Dr. Quinn also discussed dryness symptoms in patients who wear GP lenses. He offered the following tips for a differential diagnosis between "true" dryness and masquerading dryness:
• Look for a thin tear prism.
• Assess tear quantity with the phenol red thread test rather than Schirmer strips for improved patient comfort.
• Instill lissamine green to assess drying of the anterior ocular tissues. Wait a few minutes, then inspect the cornea and bulbar conjunctiva for staining. Use a low light level to avoid washing out the staining with too bright a light.
• Instill sodium fluorescein immediately upon lens removal to inspect for mechanical irritation from excessive movement or from a poorly moving, low-riding lens and to observe tear breakup time. Dr. Quinn suggests changing the fit or material after discussing the case with the CLMA member laboratory consultant.
• Evaluate for blepharitis, lid wiper epitheliopathy and meibomian gland dysfunction, which cause discomfort and mucous coating on the contact lens.
• Evaluate if hypoxia contributes to contact lens-associated dryness. Work by Mandell and others provides us with a very good understanding of corneal oxygen requirements. Hypoxic symptoms and clinical signs both increase later in the day. It's important to carefully evaluate the cornea for neovascularization, microcysts and striae. The solution is almost always to change to a higher-Dk lens material. Your CLMA member laboratory is invaluable in making recommendations for lens designs and materials.
• Poor wetting surface conditions and contact lens-associated problems may occur from the use of lotions, "contaminated" hand soaps, improper use of care systems and/or lens overwear. If this is the case, consider changing the lens care regimen and instruct patients to use, for example, a bar soap versus a liquid pump or soft soap.
• If a GP lens-associated dryness problem results from a solution sensitivity, advise patients to change solutions with symptom onset or keep the same lens care regimen for the patient but change the GP material.
• Look for diffuse staining with a Wratten filter. If staining occurs inferiorly, it's usually from desiccation. If superiorly, it usually results from mechanical rubbing from the contact lens.
Table 3 offers Dr. Quinn's tips for enhancing the ocular environment.
Fitting Post-surgical Corneas
Michael DePaolis, OD, highlighted atypical contact lens applications for patients who have experienced infectious keratitis as well as both traumatic and surgically induced irregular astigmatism.
Case 1 It's essential to evaluate how the cornea's physiology has been compromised from an epithelial, stromal, endothelial and ocular surface perspective. It's equally important to assess the corneal topography because apical displacement often provides an insight into how a contact lens will fit. In this particular case, the patient underwent myopic LASIK with two enhancements in each eye. The resulting ectasia-induced topography dictates that you would fit this patient much like you would an individual who has pellucid marginal degeneration.
|Six Recommendations for Clear and Safe Contact Lens Wear|
1 Always wash your hands before handling contact lenses.
2 Carefully and regularly clean contact lenses.
3 Store lenses in clean and proper case. Replace case (at least) every 3 months.
4 Use only cleaning products recommended by your practitioner. Always rub your lenses before storage, even if the solution says "no rub."
5 Never re-use old solution. (No topping off!)
6 Replace contact lenses as prescribed.
Dr. DePaolis advised listening to the patient's pre-operative contact lens history to better predict what's going to be successful post-operatively. History is often destined to repeat itself and you want to avoid prescribing lens designs that have been unsuccessful in the past. This patient had a history of GP contact lens failure and was successfully prescribed SynergEyes (SynergEyes, Inc.) lenses.
Case 2: This patient underwent radial keratotomy (RK) OU with an enhancement OD for a refractive error of –11.25 –0.50 x175 OD and –9.50 –0.50 x110 OS with 20/30+ VA OD and OS. The post-operative topographies revealed significant flattening with a decentered corneal apex and associated complaints of diurnal fluctuations in vision. While the right eye had 16 incisions and the left eye eight incisions, the right eye proved to be a less complicated fit. This case exemplifies the fact that the post-operative flattened optical zone (OZ) is more predictive than the actual number of incisions. As RK results in full thickness corneal changes, you must monitor for epithelial erosions, incision line keratitis and neovascularization.
A caveat in prescribing for post-surgical patients is "think GP CLs" for those who articulate complaints of diurnal fluctuations in vision.
Pacific University College of Optometry's Jennifer Smythe, OD, MS, discussed clinical scenarios that challenge practitioner skills in diagnosing common contact lens complications based on:
• The SOAP format:
– Subjective complaints
– Objective findings
– Assessment strategies including differential diagnosis.
– Plan for common management and treatment
• Making the proper differential diagnosis of contact lens-related disease.
• Understanding the rationale of therapeutic bandage contact lenses.
Piggyback Lens Fitting Dr. Smythe views piggyback lens systems as appropriate for use in keratoconus, penetrating keratoplasty, post-trauma and post-refractive surgery. She described a piggyback lens design used post-RK with imperfect wound closure and gape. A GP lens corrected the irregular astigmatism but was uncomfortable due to mechanical interaction on the area of wound tilt. She said, "The ultimate is a soft contact lens on the cornea that makes the surface more regular and more comfortable, and then the rigid lens on top."
Dr. Charles May was one of two awards dinner honorees.
Citing a keratoconus patient having a 13.00D difference between the steepest area of ectasia and the flatter superior cornea, she highlighted:
• Being aware of significant disparity in curvature along the vertical meridian of the cornea.
• Observe for not only excessive apical bearing but also superior impingement and seal off of a GP contact lens, which results in "swirl staining" and a contact lens that not only can't move freely up and down during the blink, but also can cause the epithelium to break down.
The bottom line is selecting a high-Dk contact lens for both materials. Whenever possible use a silicone hydrogel as the base for the piggyback modality.
Dr. Smythe's pearls:
• Steepen the GP contact lens base curve radius if the lens rides nasally or temporally.
• Flatten the base curve radius if the GP rides inferiorly.
• Increase the optical zone and overall diameter if the GP contact lens rides superiorly.
Multifocal GP Troubleshooting
A baby boomer turns 50 every 7.5 seconds, with 94 percent needing correction over this age. These people will live up to one-half of their lives as presbyopes, presenting a significant opportunity for contact lens practice growth. Stephen P. Byrnes, OD, discussed today's multifocal GP lens designs. He helped take the mystery out of knowing which design type creates clear distance, mid-range and near vision to optimally benefit patients. Dr. Byrnes recommends using CLMA member laboratory fitting guides and providing your laboratory and consultant with sufficient data for each custom design GP multifocal contact lens.
One lens design Dr. Byrnes discussed is Conforma Laboratory's VFL 3 simultaneous vision GP multifocal design, which uses a high eccentricity aspheric back surface to create add power as the lens surface flattens moving away from the center of the lens. Fit this lens 4.00D to 6.00D steeper than flat K. It should ideally remain centered on the cornea with the optical center directly in front of the pupil, allowing patients to focus on near reading tasks, their computer screen or an object across the street.
A second design, Essilor's ContinuVu, is a modification of the de Carle concentric bifocal. It's most suitable for early and some moderate presbyopes. This progressive add multifocal uses a combination of spherical and aspheric curves on the back surface and has a 2mm-diameter central distance zone. With lens translation on downgaze, it generates a moderate add effect (up to +1.50D).
The Boston MultiVision (Bausch & Lomb) is a multi-aspheric back-surface progressive multifocal lens that can generate up to +1.50D add power with lens translation. An additional add effect can be attained with use of front surface aspherics (up to +2.50D add). This lens has a reverse geometry peripheral curve that aids in lens centration.
Blanchard Laboratory's Essential and Essential Xtra are translating multifocal lens designs that use S-form technology to produce multifocal optics on the back surface of the lens, generating progressive add power. Both lens designs are available with three different distance zone diameters. The Series 1 design has the largest distance zone but less attainable add. Use Series 1 for emerging presbyopes. The Series 2, which has a smaller distance zone and greater add potential, is the most common series prescribed. The Series 3 has the smallest distance zone and the highest attainable add. Use this series for mature presbyopes.
|Enhancing the Ocular Environment|
• Lid soaks/scrubs
• Tear enhancers (Restasis [Allergan], omega-3 capsules, etc.)
• Clean, smooth lens surface
• Lubricating drops
• Compatible lens care system
Despite this range of Essential lens designs, at times you need yet greater add. Blanchard's CSA add enhancement can meet this need. This concentric spherical add (+0.50D to +2.00D) can be incorporated into the periphery of the front surface of the lens.
Changing the base curve of this design changes the fit; a steep fit will center better, a flat fit will translate better but may decenter laterally. The best lens fit exhibits a good balance of centration and translation. Changing the series also affects the fit. For example, switching from a Series 2 to a Series tightens the fit, while changing a Series 2 to a Series 3 loosens the fit.
Coming in 2008
The 34th Annual Invitational Bronstein Seminar will take place from Jan. 11 to 13, 2008 in Scottsdale Ariz. CLS