Join Johnson & Johnson Vision and renowned contact lens researcher Dr. Lyndon Jones for a discussion on why lens selection matters. Dr. Jones is the Director of the Center of Ocular Research and Education and a distinguished professor at the University of Waterloo. He is one of the leading voices in the discussion on whether contact lenses are still safe to wear amidst the pandemic. Dr. Kurt Moody and Dr. Carol Alexander of Johnson & Johnson Vision join in weighing in on the topic in this video.
Why does lens selection matter?
The lenses you choose will ultimately affect your patients’ overall experience with them. These questions and considerations are the first step to determining which modality and material to choose when prescribing lenses.
Patient history and symptoms
When prescribing lenses to patients, you’re looking at various factors including the patient’s initial history and visual symptoms, as well as their clinical findings (eg. refraction, keratometry, ocular surface pathology, etc). It’s crucial that you’re able to set reasonable expectations to ensure a satisfactory experience for both you and the patient.
Asking your patient about any symptoms they’re experiencing BEFORE beginning lens wear will help to ensure that you’re able to treat any underlying conditions before beginning treatment, and set reasonable expectations.
Learning about your patient will ultimately set them up for a better outcome. Allergies, smoking, ocular surface disease (OSD) —these factors may all adversely impact CL comfort. Furthermore, getting an idea of what your patient wants will help as well. Do they have an occupation that requires them to wear their lenses for long periods or a strong desire to sleep in their lenses thus requiring long-wearing time contacts? Or are they a social wearer or athlete who relies on their lenses just a few times a week?
Clinical examination
However, there are numerous considerations when it comes to selecting the ideal contact lens choice for each patient. Conducting a thorough case history and clinical exam before beginning the fitting process will help to mitigate the potential for pre-existing issues to affect future lens wear.
Tear assessment
Run a noninvasive tear film stability test (NIBUT) to help determine which lenses might be better for the patient. Patients with a shorter NIBUT may be more symptomatic and therefore have decreased CL success.
Tear film volume
- Schirmer test - can be quite irritating
- Phenol red thread wetting length - less invasive
- Tear meniscus height - very noninvasive
These tests may all help to predict how symptomatic the patient will be.
Fluorescein examination
Not helpful when choosing lens materials but provides useful information regarding the integrity of the corneal and conjunctival epithelium.
Lid examination
What's the integrity of the tarsal conjunctiva; is it smooth, is it inflamed? Hyperemia and papillae may indicate allergies and also an increased potential for CL discomfort. Blepharitis and MGD patients often have more gram-positive bacteria and are more at risk for developing infiltrates. MGD patients will likely do better with a daily disposable.
Lid wiper epitheliopathy
Closely related to friction and microtraumas; better to prescribe a highly lubricious material.
Demodex
Should be treated before beginning lens wear.
The patient’s history, tear film, and their lids and ocular surface should all be assessed prior to making a new contact lens fit. Once you’ve conducted the initial examination(s), you can begin to choose the right lenses for your patient.
Choosing between lens options
Now that you’ve collected information from the patient, it’s time to make the prescribing decision. It’s ultimately up to the practitioner to decide which lenses are best for their patient, and from there to choose between daily disposables and reusable lenses.
Hydrogel
- Usually a daily disposable lens
- Thin and conform to the eye’s surface
Silicone Hydrogel
- More likely to be reusable lenses
- If the patient is likely to be getting less oxygen to the eye—for example, a high myope—then SiHy lenses are likely a better option.
So, you’ve done your homework. You have a good understanding of your patient and their needs. Now it’s time to ensure that you prescribe the best possible lens.
What makes for a good CL-wearing experience?
The fewer surprises the better, right? It’s great when you’re able to set reasonable expectations for the patient and help them improve their vision and wearing experience. Hygiene is a major factor in CL success, as dirty lenses and infections are never fun.
However, besides traditional advice like handwashing and proper lens cleaning, the patient’s overall comfort is also a major factor in hygiene. Eye rubbing, dryness and any manipulation of the lens can lead to compromised cleanliness, so it’s important to remember that comfort enables hygiene.
The four contributors of comfort
The left side of this chart depicts the CL safety profile, with DD being the safest and EW being the riskiest. The right-hand side shows 8 modifiable factors that can affect the patient’s overall experience when it comes to contact lens hygiene.
Edge design - Minimizes the contact lens edge to ocular tissue interaction. Evaluating for lid wiper epitheliopathy is a good way to test if the edge design is optimal for the patient, but remember that it's best to look for later in the day.
Modulus - High modulus lenses sometimes are less comfortable but too low of a modulus can negatively affect handling.
Coefficient of friction - Most lenses now have low coefficient of friction but ACUVUE® lenses not only have very low values but they also maintain that value over the course of a simulated day.
Wettability - PVP (ACUVUE®’s internal wetting agent K90) is a unique molecule that is both hydrophilic and lipophilic, or amphiphilic—mimicking the natural tear film.
Eye rubbing, lens adjusting, etc. can all introduce pathogens into the eye. Comfortable lenses and proper patient education will both help to minimize the risk of self inoculation.
The importance of patient education
Patients are more informed than ever nowadays. They’re able to conduct their own research online and may even come armed with their own predeterminations before their initial contact lens appointment. However, it’s important that you’re able to assess their understanding and provide them with proper instructions for lens wear while dispelling any myths and correcting potential misconceptions they may have come across.
A lack of understanding and education is a factor in many negative CL experiences. Showing videos of proper application and removal of lenses is a great tool for ensuring that your patients are using their lenses correctly.
One analogy that may help patients understand their ocular surface condition is that of a windshield wiper that’s too dry.
Finally, being able to work with your patients to find the best solution for their individual needs is imperative. If cost wasn’t an issue, everyone would likely be getting daily disposables. However, sometimes the patients’ circumstances may affect which lens options are feasible for them.
Use the chart to assist you in making personalized recommendations for your patients!
