THE PRESBYOPE IS IN THE MOST need of help from the eyecare practitioner. For the first time in their lives, these individuals have a difficult time seeing things up close because of the loss of lenticular elasticity. Additionally, no other physical change in the body provides individuals with a constant reminder of their age as much as the inability to focus things at near. Adding a layer of complexity to treating the presbyope is that a significant proportion of these people have distance vision requirements as well. In addition to multiple power requirements, aging is characterized by destabilization associated with significant changes in the tear lipid layer producing less protection from evaporation in the aging population.¹

In light of all of the challenges in correcting presbyopia, there is no better time to be a presbyope because of the technologies available. We are practicing in an era of opportunities to care for these patients using advanced technologies that have been specifically designed and engineered to meet their needs. So what are the characteristics of a contact lens technology that would be ideal to optimize the presbyope’s visual performance? Here are the things I feel would be ideal characteristics of a lens for these patients.

It Needs to Be Comfortable

Optimizing contact lens properties for an exceptional wearing experience is critical. The Tear Film and Ocular Surface Society (TFOS) highlighted in the Dry Eye Workshop II (DEWS II) report the importance of homeostasis of the tear film in the maintenance and promotion of a healthy ocular surface.² As such, it is critical when considering contact lenses for a patient to understand the contact lens design and how it promotes a homeostatic wearing experience.

Ideally, the material would be a low-modulus material but have high oxygen permeability. This has traditionally been a difficult feat to accomplish because silicone is highly oxygen permeable but unfortunately contains a high modulus. Traditional hydrogel options are typically a low modulus but also have low oxygen permeability. The ideal solution would be a silicone hydrogel lens with a low modulus.

Additionally, the ideal material for a lens contains high water content that retains this content throughout the day. Hydrogel materials are traditionally higher in water content, but there are challenges in retaining the water. Silicone hydrogel lenses are traditionally a lower-water content material. The ideal solution is a silicone hydrogel material with high water content that maintains its moisture.

The one property of contact lenses that is rarely discussed is the bulk properties of the lens and how the lens divides the tear film and disrupts the natural tear film dynamics on the ocular surface. Increasing understanding of the dynamics of a lens in the presence of the tear film highlights the complexities of the relationship. As such, a contact lens that has molecules including electrolytes, osmoprotectants, and moisturizers that allow the lens to interact with the tear film in a more homeostatic state would be ideal to optimize the contact lenses-tear film relationship.

It Needs to Correct a Range of Vision

An ideal vision-correction solution for presbyopes would reintroduce a visual range to patients that allows for focusing distance and near, along with the full range in between. As any presbyope can attest, their world is not as simple as “distance” vision and “near” vision that are prespecified at 2 distinct distances. They have a wide range of visual needs. They have to be able to see things in the distance and seamlessly transition to focus on things up close. An example is someone driving who then needs to see his or her speedometer or directions in the car. Additionally, there has to be the ability to see things in intermediate ranges, including computer screens.

The New Contact Lens Solution Is Now Available

Recently, a new contact lens has become available that addresses the needs of the modern presbyope. The Infuse Multifocal (Bausch + Lomb) contact lens was designed to optimize its presence on the ocular surface and deliver those wanted characteristics to promote homeostasis and optimize visual function.

The Infuse Multifocal contact lens was created with a next-generation material combining both long- and short-chain silicone polymers, creating a unique low modulus lens providing a material that is very soft. This material provides a high level of oxygen permeability through the lens. Polyvinylpyrrolodine is an important part of the material properties of the lens, affording a lens with high water content. This lens is unique in that it has demonstrated moisture retention within the lens for up to 15 hours. High water content and high oxygen permeability are historically properties within a lens that have been mutually exclusive. The Infuse Multifocal was engineered to combine these 2 properties within a lens, knowing that they are both advantageous for optimal lens wear.

Unique to the Infuse Multifocal contact lens is that it was designed with the intent of maintaining homeostasis of the tear film when a lens is on the ocular surface. This is due to the ProBalance technology that is infused into the lens and promotes homeostasis. The ProBalance technology, as its name implies, provides a balance when the lens is on the ocular surface through the selective inclusion of electrolytes, osmoprotectants, and moisturizing agents within the lens.

Potassium is naturally found within the tear film and is an electrolyte that is a component of the ProBalance technology. Hyperosmolarity is a key disruptor of homeostasis, which is why erythritol and glycerin are also included as part of the ProBalance technology. These molecules are both osmoprotectants helping to maintain homeostasis under hyperosmotic stress. Poloxamine 1107 and poloxamer 181 are moisturizing agents that help retain moisture and provide a smooth, wettable surface.

All of these factors offer the infrastructure required to create a lens design that promotes homeostasis and provides an enhanced wearing experience. Just as important as the design are the optics within the lens that provide a presbyope with visual functionality. The optical lens design is based on the 3-zone progressive design, which provides patients with distance, intermediate, and near vision. The optical design provides a stable visual platform that provides the necessary range of vision that presbyopes are seeking.

The sophistication in the optical lens design provides a lens that has a simple fitting strategy for clinicians. It is available in low add and high add powers. Patients with an add power up to +1.50 are fit with the low add design in both eyes. Patients with an add power greater than +1.50 are fit with a high add power. This design provides patients with seamless binocular vision and the correction they need to function in a visually versatile world.

Summary

New technologies are allowing presbyopes to function utilizing sophisticated technologies that have been engineered to optimize outcomes. Embrace these technologies to offer your presbyopic patient new opportunities for visual freedom and optimized outcomes. ■

References

1. Maïssa C, Guillon M. Tear film dynamics and lipid layer characteristics--effect of age and gender. Cont Lens Anterior Eye. 2010;33(4):176-182.
2. Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276-283.

Dr. Brujic is a partner of Premier Vision Group, a successful four-location optometric practice in northwest Ohio.