Managing astigmats when they hit presybopia

July 12, 2017

Fitting toric patients is a breeze today, and we have options to allow those patients to continue to stay in their contact lenses as they become presbyopic.

As you spin your Jackson Cross Cylinder (JCC), you hope for the white dots to be selected. Oh, the happiness a spherical patient can bring to your day. Young or old, it doesn’t matter, their refractions are faster, their adaptation to everything is easier, and their contact lens fits are a bit easier and a little faster. Fingers crossed your new patient sitting in your chair falls into this group.

Cylinder has been accepted, and now the panic sets in-what’s the axis? Is it oblique? Oh, don’t let it be oblique! How high will it go? I’m thinking of the redos in my future, the distortion, the crooked walls and tilted floors, the headaches and strain, the toric lenses, the shadows, and all the explaining that has to be done.

Years ago, we thought this was our fate, but today there is no need to stress.

After I bought my practice, I heard too often from patients they were told they were not candidates for contact lenses because they had a disease called “astigma.” The options available for our patients and the ease in which we can fit our patients have dramatically changed-especially for presybopes and astigmats. Astigmatism is no longer a scary prescription that we need to shy away from fitting contacts.

Fitting toric patients is a breeze today, and we have options to allow those patients to continue to stay in their contact lenses as they become presbyopic.

 

Options for the presbyopic astigmatSoft multifocal toric lenses are lenses that have it all.

Coopervision offers Proclear Toric Multifocal lens in two base curves.

Many gas permeable labs have monthly to conventional soft multifocal toric lens options. These lenses are great for patients who have high prescriptions and need all prescription parameters to be included in their vision correction.

If a patient has astigmatism in only one eye, you can fit a multifocal toric lens in that eye and a spherical multifocal in the spherical eye. Both eyes will still have a multifocal lens option providing a full range of vision from both eyes. In this case, I try to keep the modality of both lenses the same for patient compliance and ease.

Modified monovision is fitting a multifocal contact lens in one eye and a toric lens in the other. The dominant eye typically carries the astigmatism, so fit the dominant eye with the toric lens. The non-dominant eye has little to no astigmatism, which can be masked with a spherical multifocal lens. The non-dominant eye will provide the near correction to the visual system while providing some intermediate and distance help.

 

This type of fit may be used if both eyes have astigmatism, but the dominant eye is unable to adapt to a multifocal lens. This option may also be chosen if a patient is interested in a modality such as a two-week or daily replacement schedule which is not available in a multifocal toric lens.

Monovision can be an option when the patient does not successfully adapt to multifocal contact lenses. The dominant eye is fit with a toric or spherical lens set for distance, and the non-dominant eye is fit with a toric or spherical lens set for near. If a patient has astigmatism in both eyes and wants a biweekly or daily disposable lens, this may be the only option. Difficulties that may arise with monovision include depth perception, night driving, and a lack of intermediate vision.

 

Gas permeable (GP) lenses are a forgotten tool that some practitioners today do not want to fit because of the perceived difficulty to fit and discomfort of the lenses. GP lenses provide great clarity in vision and are able to neutralize high amounts of corneal astigmatism with spherical, aspheric, and back surface toric lens designs.

GPs are a good choice for astigmatic presbyopic patients. The back surface of the lens can adjust for the astigmatism, while the front of the lens can address the reading add required.

These lenses can be ordered empirically from your lab with just a few pieces of information. If you provide your lab with keratometry (K) readings, current prescription, horizontal visible iris diameter (HVID), pupil size, and eye dominance, your lab of choice will design a lens for your patient and will walk you through the fit.

Materials, designs, coatings, and size of lenses allow for greater comfort and very crisp optics. Consider theses lenses for your patients, especially if you are unable to achieve clarity with soft toric lenses.

Scleral lenses are very popular now with their ability to mask high amounts of corneal astigmatism and provide clear, crisp vision to irregular corneas. When I started fitting scleral lenses eight years ago, we had only spherical scleral lenses to work with. We now have front torics and front aspheric multifocal designs, as well as labs that are able to create front toric multifocal scleral lenses. We live in a great time to be able to help our patients achieve better comfort and vision with scleral lenses.

Distance contact lenses under readers or computer progressive addition lenses (PALs) is a strategy used as a back-up plan when patients fail to adapt to multifocal lenses or when modified monovision or monovision has not been successful. I will also use this option for patients who do not have the time, money, or energy to move forward with a multifocal contact lens fitting. When a patient wants to remain in her daily disposable or biweekly lenses, this may be her only option as well.

Communication is key

When making recommendations to our patients, the strength of our recommendation comes from the relationship we have built with them and the level of professionalism we have shown throughout the exam. How we speak and communicate with out patients determines how they perceive our abilities. As a new grad, I had to use my words to create trust. This was done through kindness, empathy, and taking the time to explain things to patients, showing them my knowledge and empowering them to understand their condition.

 

To explain astigmatism, I use a model and describe how the natural eye works. I explain how light enters the eye, bends and lands somewhere inside the eye. If the focal point lands on the retina, we do not need glasses; if it lands in front or behind the retina, we need glasses to bring the focal point to the retina. Then I explain how an astigmatic eye creates two focal points, which will need two different prescriptions to bring both of those focal points to the retina. Patients will forget but understand in the moment and will appreciate the 30 seconds given to explain something they didn’t understand and often didn’t know they had.

To explain presbyopia, I use a system of 10 units, which I created years ago. It was designed as a simple method to ease the tension of and to provide more understanding of presbyopia.

The general loss of accommodation of 2.50 D can be compared to a loss of 10 units of accommodative strength if broken into 0.25 D steps. I describe to my patients that the focusing system has 10 units of energy, and over a 35-year period we will all lose those 10 units. The rate at which we do lose them is individual and depends on the amount of near work we do.

For example, if a patient presents to the clinic with a +1.50 D add, he has more than likely lost six units of his accommodate muscle energy and is performing with only four units of his initial ability. This patient would require six units (+1.50 D) of add support to return him to his full potential. These six units are added to his distance prescription to give him his best reading vision. With the six units of magnification plus his natural four units, the patient’s accommodative system is at 100 percent. The four natural units remaining will eventually be lost, and the patient understands that four more steps of change still lie ahead.

 

This explanation helps patients understand where they are in the process, how much of the accommodative system they have lost, and how much they have remaining, enabling them to track their own personal rate of change. 

 

The system of 10 units can also be used to clarify how a pair of progressive lenses is a linear system, while a soft multifocal contact lens is typically designed in a circular pattern. Explaining the differences in glasses and contact lens designs is key to clarifying how these products work as well as understanding why starting earlier in the presbyopic process prevents the frustration that so many feel with progressive glasses (See Figures 1A and 1B).

The most important part in communication is the need to start early to achieve greater success with these fits. Patients with a lower add amount typically have an easier time adapting to both progressives and soft multifocal lenses as compared to those more mature presbyopic patients with much higher adds.

Fitting fees

After years of education, countless hours of practicing on each other, years of continuing education, and years of experience, we are valuable professionals and deserve to be paid well for the knowledge we have and the services we provide. I don’t shy away from discussing fees and costs in my practice. We have open and honest conversations of prices and are proud of the quality of service we provide for those fees.

I approach explaining any service that has an additional fee is the same manner with no fear. I explain the process, what will be received, the time it will take, my expectations of the outcomes, and the cost for the service. Then I wait. If the patient agrees to the cost, we move forward with the service at that time or at a separate visit, time depending. Money does not have to be an uncomfortable topic. ODs can calmly and confidently explain the value and benefits of the service we are providing, giving patients the choice to choose. Don’t give your services away for free.

Bringing it together

Our contact lens patients have not thought of an age when they want to stop wearing their lenses. It is our job to make sure that they never have to give up on a luxury to which they have become accustomed. Presbyopia should not be a limiting factor in their contact lens success. Being able to keep your astigmatic patients in their lenses as they age will keep your patients happy, help them to remain functional while feeling young, and will ultimately help you grow your practice.

Read more on toric contact lenses by visiting our Toric Contact Lens Resource Center