Make The Perfect Match
Make The Perfect Match
Base your contact lens recommendation on patient population and subjective visual, lifestyle and comfort needs.
ALAN GLAZIER, O.D., F.A.A.O., ROCKVILLE, MD.
PHOTO BY GEORGE DOYLE
In the song "Wooden Ships," Stephen Stills sings "If you smile at me, I will understand, ’cause that is something everybody everywhere does in the same language." While that may be true, we all know firsthand that not everyone smiles wearing the same contact lenses. This is because each patient population has their own set of vision, lifestyle and comfort needs.
Therefore, one must realize that a successful lens fit isn't based on the science of lens fitting alone, but on one's ability to customize the fit to the patient — the art. Coupling the science with the art of fitting enables you to effectively narrow the feasible lens choices for the patient and subsequently make a strong recommendation. Unfortunately, some clinicians fail at the latter.
Imagine this: Your primary-care physician has just diagnosed you as having a sinus infection. Instead of saying: "I'm going to prescribe clarithromycin to eradicate the bacteria causing your infection," he says, "I can give you clarithromycin or cephalexin to get rid of your sinus infection. Which would you prefer?" Would you stick with this doctor? Probably not.
All patients want a practitioner who shows he's the expert. In your case, your skills and confidence shine through when you make strong recommendations regarding lens wear, spectacles and ocular medications. Fail to assert your recommendation, and you may fail to remain that patient's eyecare practitioner.
Here, I discuss the typical types of contact lens wearers and what might be some of the best type of lenses for these patients.
Children, tweens and teens
We have traditionally recommended GP lenses to children (typically age eight through 11) for three reasons:
1. Researchers in the past had reported that soft contact lenses increase myopia progression.1
2. Studies have revealed that GP lenses may be effective in actually retarding myopia progression.2,3 In fact, many eyecare practitioners, including myself, recommend orthokeratology (made of GP materials) to children whose parents inquire about potential methods for myopia control. Our recommendations are based on studies that demonstrate a statistically significant corrective and preventative/control effect in childhood myopia.4,5,6 While controversy surrounds this method of vision correction — the entire mechanism behind myopic progression has not yet been well defined, leading some to question the lens' ability to reduce myopia — parents have the option of doing nothing or trying something that may have validity.
3. Children find the insertion and removal of GP lenses easy, as they are small and don't require the child to touch the eye for removal.
Recently, however, more practitioners, including myself, have begun offering soft lenses to some members this patient population. The Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) study, presented at the Association for Research in Vision and Ophthalmology (ARVO) 2008 meeting, revealed that soft lens wear was not shown to increase the rate of myopia progression in children through a three-year period.
|Recommendations For Contact Lens Wear By Age Group|
|Children (ages eight to 11):|
• GP lenses
• Single-use lenses
Tweens (ages 10 to 12) and Teens:
• Single-use lenses
• One-week daily wear lenses
• One-month daily wear lenses
College/Workforce Through Incipient Presbyopia (ages 20 to 40):
• Extended-wear (overnight) lenses
• Single-use lenses
Presbyopic Patients (ages 40 and older)
• Simultaneous vision aspheric GP lenses
• Aspheric soft lenses
• Multifocal toric lenses
• Translating multifocal toric GP lenses
Dry Eye Patients
Evaporative: any type of lens material
Aqueous tear deficient: low-water content silicone hydrogel
Specifically, the results of the Vistakon-funded study revealed that although myopic progression was statistically greater in lens wearers than in spectacle wearers, the difference of 0.19D was not clinically meaningful. Also, the data showed no difference in the axial growth of the eyes between the two groups.
The researchers arrived at these conclusions after measuring the refractive error, corneal curvature and axial length of 484 eight to 11-year-old children whom they randomly assigned to wear either single-vision spectacles (237 subjects) or two-week daily wear or single-use soft lenses (247 subjects).
If the patient's ocular health (allergies, etc.) and lifestyle (computer use, etc.) reveal he's a good candidate for soft lens wear, and he's able to correctly insert and remove the lens, I often recommend a single-use soft lens. Why? Because a sterile, fresh lens every day is least likely to compromise the cornea — something that should influence our clinical decision-making when fitting a still-developing eye.
Because tweens (ages 10 to 12) and teens have the maturity level necessary to insert and remove soft lenses, I begin offering single-use, one-week and one-month daily wear lenses to viable candidates in these populations. (I've discovered patients fit in the two-week modalities generally over wear their lenses, putting themselves at risk for eye infections. As a result, I offer the two-week modality in a one-week wear schedule, which patients find easier with which to comply. I present this lens wear as "new week, new lens," which I have discovered fosters their compliance.) An example of a viable candidate: An avid athlete. GP lenses trap dirt and debris more readily than soft lenses due to a gap that exists between the lens and the eye. This, in turn, can cause ocular discomfort in individuals who spend a great deal of time "playing" outdoors.
I offer the two-week (on a one-week wear schedule) and one-month modalities to viable candidates who, through parent and patient questioning, reveal a maturity level required to adhere to the necessary lens care. For instance, if the patient answers "yes" to the question: "Do you have to be told to do your homework?", I may guess he's not responsible enough for the two-week or one-month daily wear lenses. In this case, I strongly recommend a single-use soft lens, as this modality doesn't require a lens care regimen. Remember: Fusarium and Acanthamoeba infections in these populations have life-long negative implications, as the eyes of tweens and teens, like the eyes of children, are still developing.
College/workforce through incipient Presbyopia
I offer 30-day extended-wear (overnight) and single-use lenses to college students, members of the workforce and incipient presbyopic patients for four reasons:
1. These patients still have enough accommodative ability to see clearly through a single-vision lens at many ranges with relative comfort.
2. They appreciate modalities that save them time and effort, as their lifestyles (studying, working long hours, raising children, etc.) now require more of their time and memory. (These lenses afford them one less thing to have to remember, in terms of lens care.)
3. Some are considering LASIK, though they either aren't sure they want to go through with it, or they don't yet have the funds needed for the procedure. I educate these patients that extended-wear lenses are a nice alternative similar to LASIK in that they provide a form of hassle-free vision.
4. Single-use lenses are excellent for alleviating and/or solving discomfort issues that stem from the environment. For instance, computer users often have a reduced blinking frequency. This is because they've become conditioned to stare at their monitors for prolonged periods of time. This, in turn, can lead to ocular dryness, sometimes making lens wear particularly uncomfortable for those wearing two-week or one-month daily wear lenses. With each day of wear, the lens surface material, in contact with the palpebral conjunctiva, breaks down and/or accumulates debris. A fresh lens everyday can provide comfort to these patients. To further bolster comfort, I educate these patients about ocular elevation eyestrain, which induces dry eye, so they position the height of their chairs and monitors to ensure a downward gaze on the monitor.
Making the perfect lens match for these patients requires a great deal of optometric trial and error. This is because many presbyopic patients are often not willing to put up with the compromise of distance inherent in simultaneous vision presbyopic lens options. As a result, my philosophy in fitting this patient population is "underpromise, overdeliver."
I carry out this philosophy during the initial consult. First, I always determine what visual ranges are important to the patient by asking him what activities comprise his weekdays and weekends. Then, I educate the patient about his vision and currently available options. Finally, I explain the possibility of having to prescribe spectacle wear "over" the patient's lenses to correct whatever distance or near residual refractive error may remain after maximized fitting. Specifically, I explain that in some cases, especially in advanced presbyopia, I've found that these contact lenses will allow spectacle-free vision 90% of the time, as opposed to 0%, depending on the patient's refractive error. Educated presbyopic patients are often satisfied lens wearers willing to deal with the minimal eyeglass wear.
I offer incipient to moderate presbyopic patients simultaneous vision aspheric GP, aspheric soft or multifocal toric designs, and, in some cases, translating GP designs. The best candidates for these lenses don't want presbyopia to stand in the way of wearing lenses, they need to sustain mid-range vision most of the day (computer users), and they may find monovision difficult with which to contend.
I trial fit most patients who present in a GP lens in an aspheric GP first. These patients are already used to the lens awareness of a GP lens and, therefore, are more likely to successfully acclimate to their new lens.
I offer translating multifocal RGPs to patients who spend most of their time avidly reading print (newspaper, magazines, etc.). This is because this lens has a wider, single-vision zone than the mid-range vision lenses.
Dry eye patients
In 2007, the International Dry Eye Workshop (DEWS) Definition and Classification Subcommittee determined that dry is composed of two classes: evaporative and aqueous-tear deficient. Regardless of class, one must aggressively treat their underlying causes prior to fitting the patient in a contact lens. Remember: The patient will never be fully comfortable unless you first improve his initial dry eye status.
In the case of evaporative dry eye, I don't lean toward any specific lens material. This is because the patient has some chance of achieving successful wear in multiple lens materials, as long as my treatment is successful in mitigating some of the lid disease and restoring some of the lipid layer of the tear film.
I tend to offer my aqueous-tear deficient dry eye patients a low-water content silicone hydrogel lens that has a non-ionic surface. Why? In theory, and sometimes in practice, the lens allows a great portion of the available aqueous tear to come in contact with the eye, concurrently resisting protein deposits and thus, providing a more comfortable experience. Proteins in the tear film are attracted to ionic polymers. On a dry ocular surface, the protein/water concentration is higher than a wet surface, creating an environment that is less comfortable with a lens made of an ionic polymer.
Although it's impossible to know for certain how the aforementioned patients will perceive their lenses through full days of wear, by coupling the science with the art of fitting, you provide your patients with an excellent chance of achieving successful wear from the start. Still, let patients know that you are available to them via follow-up visits, e-mail or text, should they experience any less than optimum results. Having access to you, the doctor, lets the patient know that you are invested in his lens wear experience. This adds to the patient's perception of a successful fit, which will make him smile — something "everybody everywhere does in the same language" to convey a level of satisfaction and pleasure. OM
1. Walline JJ, Jones LA, Sinnott LT, et al. A randomized trial of the effect of soft contact lenses on myopia progression in children. Invest Ophthalmol. Vis. Sci. 2008 Jun 19 [Epub ahead of print]
2. Khoo CY, Chong J, Rajan U. A 3-year study on the effect of RGP contact lenses on myopic children. Singapore Med J. 1999 Apr;40(4):230-7.
3. Walline JJ, Mutti DO, Jones LA, et al. The contact lens and myopia progression (CLAMP) study: design and baseline data. Optom Vis Sci. 2001 Apr;78(4): 223-33.
4. Cho P, Cheung SW, Edwards M. The longitudinal orthokeratology research in children (LORIC) in Hong Kong: a pilot study on refractive changes and myopic control. Curr Eye Res. 2005 Jan;30(1):71-80.
5. Mika R, Morgan B, Cron M, et al. Safety and efficacy of overnight orthokeratology in myopic children. Optometry 2007 May;78(5):225-31.
6. Walline JJ, Rah MJ, Jones La. The Children's Overnight Investigation (COOKI) pilot study. Optom Vis Sci. 2004 Jun;81(6):407-13.
|Optometric Management wants to hear from you!|
|Do you have a tip or tips on fitting specific patient populations in contact lenses? If so, please send them to Jennifer Kirby, senior associate editor, at firstname.lastname@example.org.|
||Dr. Glazier practices in Rockville, Md. and founded Vision solutions Technologies, Inc., a corporation to develop LiquiLens, an intraocular lens for low-vision patients. E-mail him at email@example.com.|
Optometric Management, Issue: October 2008