Let’s presume you are familiar with the multiple head-to-head studies that find approximately 7 out of 10 patients prefer multifocal contact lens correction over monovision.1-3 Let’s also assume you are motivated to do what’s best for your patients. Finally, let’s suppose you assess a contact lens service fee that properly reflects your expertise. With these pieces in place, you are ready to embark on a gratifying, and financially satisfying, journey in visual correction: meeting the contact lens needs of the presbyope.
Patient Refractive Error
It is well recognized that distance power changes as small as 0.25 diopter can have a significant impact on multifocal contact lens performance. Therefore, an up-to-date, detailed refraction is critical to selecting the proper initial multifocal contact lens power.
I define a detailed refraction as one in which the patient is given just enough minus (or less plus) power to achieve clear distance vision, but no more. In other words, if you offer a choice of an additional -0.25 during your manifest refraction, and the patient is equivocal as to whether it benefits them visually, don’t give them that added minus power. Additionally, perform a binocular blur balance to ensure both eyes are in sync with each other. When assessing bifocal add power, offer just enough plus to do the job.
The goal is to provide clear vision with the least amount of difference between the distance and near power. The greater the difference, the more they compete with each other, potentially leading to visual disturbance. The smaller the difference (the lower the add), the better they work together.
Astigmatic error plays a major role in guiding our choice of multifocal lens design. It has been shown that uncorrected astigmatism of 0.75 to 1.00 DC leads to significant loss in acuity,4 so choose designs that will correct this level or more astigmatism. Keratometry or topography findings will tell you whether the astigmatism is corneal or internal, further guiding your lens selection. For more information and resources, see “The Bottom Line: Lens Design Selection Process and Where to Go for Help” on page 29.
The Ocular Surface
Most of us are fairly diligent about examining the cornea when exploring a patient’s suitability for contact lens correction. Important considerations are corneal shape (e.g., keratometry or topography) as well as looking for signs of edema, inflammation, or other irregularities.
More recently, we have begun to appreciate the importance of examining the entire anterior segment environment, including the eyelids, for ocular surface disease. Some prospective contact lens patients may not initially complain of ocular discomfort, only to be “pushed over the edge” by contact lens wear. Proactively identifying and treating these patients will improve contact lens performance and reduce dropout.
Although a thorough review of ocular surface assessment is beyond the scope of this article, key components should include:
Questionnaires such as OSDI and SPEED are quick, easy, and have been shown to be reliable indicators of dry eye.5 When a group of more than 30 dry eye experts6 were asked what key questions should be posed to uncover dry eye, the consensus was:
- Do your eyes ever feel dry or uncomfortable?
- Are you bothered by changes in your vision throughout the day?
- Are you ever bothered by red eyes?
- Do you ever use or feel the need to use drops?
When patients say their eyes itch, I like to ask “Is it your eye or your eyelids that itch?” I find patients often mean to say their eyelids itch at the lid margin, a common symptom associated with meibomian gland dysfunction.
The same group of experts cited above recommend, at minimum, a three-part physical examination to uncover ocular surface disease:
- Eyelid examination
- Some form of staining assessment
- Tear film stability assessment
When examining the eyelids, take a few seconds to sit back and look at the patient. Do the eyelids look thickened or red? (Figure 1). Do you note any bulbar injection? Both could be signs of eyelid disease. Once you have the patient behind the slit lamp, look for debris in the lashes and take time to express the meibomian glands. If obstructed, or the expression is turbid, institute treatment prior to lens fitting. Don’t forget to evert the upper lids, especially on current contact lens wearers.
Assessing Patient Disposition
Anyone who has performed refractive testing can attest to the fact that some patients are more visually sensitive than others. I use patient response during a manifest refraction as a sensitivity barometer. Although less visually sensitive patients may be more challenging to refract, they may adapt more readily to multifocal optics. Very visually sensitive patients may need designs that provide more precise multifocal optics.
Obviously, some contact lenses provide better initial comfort than others. A patient who is bothered by the physical sensation of things in and around their eyes may be better served with a a soft lens. Conversely, a patient who is relatively insensitive to procedures such as tonometry (Figure 2) and eyelid eversion, may do quite well with a corneal GP lens and would enjoy the optics provided by such a design.
The Contact Lens Conversation
Start the contact lens conversation with a written or electronic form the patient completes at intake, which asks questions about career and leisure activities, or begin by having a technician ask questions during the initial case history. The best time for the eyecare provider to recommend contact lenses is at the end of the examination.
I think of the process of patient selection for multifocal contact lens correction as a matchmaking endeavor. As the eyecare provider, it is our job to understand each patient’s ocular condition and visual needs. As the contact lens expert, we know which contact lens designs are most compatible with each patient’s ocular condition. We are uniquely positioned to prescribe the best lens modality and design for each individual patient. For the presbyopic patient, science tells us some form of a multifocal contact lens will most often be the answer.
It’s Not All or Nothing
In the United States, eyecare providers often view patients as fitting into one of two camps: eyeglass wearers or contact lens wearers. Does your scheduler ask patients if they are glasses or contact lens patients? If so, I invite you to broaden your approach and embrace what I refer to as the “multifaceted patient concept.” View patients as complex, active individuals who are likely best served by many different forms of visual correction: spectacles, sunglasses, computer glasses, and contact lenses. Approaching the prospective wearer with this attitude opens the door to an entire population who may not necessarily care to wear contact lenses full time, but would appreciate them for activities such as jogging, skiing, or for social activities. Success with these patients is very high because most of these activities do not demand high visual performance.
Preparing for Success
Examination is important, but words serve as the key to unlock the multifocal contact lens treasure chest. Whereas designs such as toric lenses employ fitting skills based largely on testing and on-eye lens observation, success with multifocal lenses rests chiefly on clear communication.
The Priority Distance
Once a patient commits to contact lens correction, it is important to start the fitting process with a clear understanding of where the priority distance is for that patient. You can get a pretty good idea about this based on a patient’s occupation and leisure activities. For example, a data entry specialist needs clear vision at the computer distance. For a hunter, crisp distance vision is a top priority. Perhaps the best way to define this is to ask. I often say “With these lenses, my goal is to meet most of your visual needs most of the time at most distances, but at what distance do you feel it is most important you have good visual performance?” Many patients will initially reply “I want it clear at all distances.” Follow-up by saying something like “I know. I will do my best. But what is your ‘must have’ distance?” They will commonly volunteer they need to be able to see the text stream on their cell phone, or the theater stage, or their friend’s faces across the table, or some other specific visual task they perform regularly. I make a note and, should power modifications be necessary, I will bias my decision-making in the direction of the priority distance.
Once lenses are applied, the first-time multifocal contact lens patient will experience vision in a new way. They won’t know what to expect. We need to help them through the process.
Inform them it generally takes a few minutes for the lenses, and vision, to settle. Usher them to the reception area and invite them to explore their visual world by looking out the window, picking up a magazine, looking at their phone texts, and so on.
After 10 minutes or so, invite the patient back to the exam lane. Before beginning testing, ask the patient an open question, such as “How are you doing with the lenses?” This allows you to immediately zero in on problem areas, if any. If they say “These are great”, consider not making any changes to lens power unless acuity doesn’t meet safe driving standards, usually 20/40.
After you’ve obtained subjective input from the patient, measure his visual acuity under binocular conditions with the room lights up. If you start with a full distance acuity chart, the patient will naturally try to read the very bottom line. An inability to do so may lead to frustration or discouragement. Turn the visual acuity assessment into a positive experience. Start with the 20/40 line isolated on the distance acuity chart. Most patients will be able to read this quite easily, and will satisfy your need to make sure driving requirements are met. Then isolate the 20/30 line. Again, most patients will read this easily. Then move to 20/25, and if successful, the 20/20 line. As each line is read, the patient is encouraged, rather than disappointed.
Similarly, when assessing near vision, start with practical tasks that patients perform in their daily lives, such as reading cell phone texts. Performing these day-to-day tasks successfully can be powerful motivation to proceed with multifocal correction.
Give It Time
If patients are reading the acuity chart fairly well, yet complain that vision isn’t crisp, and a loose lens over-refraction suggests the power is correct, give them time. Studies have found that the brain can adapt to multifocal optics over time.7 Release them for a week or so and re-evaluate. Often, vision will be quite satisfactory.
Three Simple Rules
Be informed. Be supportive. Be patient. Follow these three rules during multifocal fitting and you will ultimately be successful. ■
- Situ P, Du Toit R, Fonn D, Simpson T. Successful monovision contact lens wearers refitted with bifocal contact lenses. Eye Contact Lens. 2003;29(3):181-184.
- Richdale K, Mitchell GL, Zadnik K. Comparison of multifocal and monovision soft contact lens corrections in patients with low-astigmatic presbyopia. Optom Vis Sci. 2006;83(5):266-273.
- Johnson J, Bennett ES, Henry VA, et al. Multivision vs Monovision: A Comparative Study. Presented at the Annual Meeting of the Contact Lens Association of Ophthalmologists, Las Vegas; February 2000.
- Richdale K, Berntsen DA, Mack CJ, Merchea MM, Barr JT. Visual acuity with spherical and toric soft contact lenses in low-to moderate-astigmatic eye. Optom Vis Sci. 2007;84(10):969-975.
- Simpson TL, Situ P, Jones LW, Fonn D. Dry eye symptoms assessed by four questionnaires. Optom Vis Sci. 2008;85(8):692-699.
- Bloomenstein M, Cunningham D, Gaddie IB, et al. Improving the screening, diagnosis and treatment of dry eye disease. Review of Optometry supplement; June 2015.
- Fernandes PR, Neves HI, Lopes-Ferreira DP, Jorge JM, Gonzalez-Meijome JM. Adaptation to multifocal and monovision contact lens correction. Optom Vis Sci. 2013;90(3):228-235.