- What does behavior have to do with vision?
- Can personality impact our eye power?
- Can glasses guide visual changes?
The Behavioral Optometry perspective:
People’s behavior is generally consistent, and this translates to how we use our eyes. Our personality traits get expressed in all facets of life. But they also are helping us to create the visual system which best meets the demands we provide it.
With years of patient care experience, "behavioral" optometrists have come to recognize particular patterns which are common to people with particular "Refractive States."
What is a Refractive State?
- "Refractive state" is the neutral term used to describe how light is bent as it enters the relaxed eye, and where it comes into focus.
- "Refractive error" is the more commonly used term for Refractive State. However, by calling it an "error," this term implies that anything other than a neutral or "plano" refractive state is out of balance. It carries a bias in perspective which may overlook the advantages of developing myopia, astigmatism, or hyperopia, particularly in modest degrees. It also suggests that when these differences from neutral are identified, they require compensation. A Behavioral Optometrist may measure the same Refractive State and consider it to have a positive adaptive value, leaving it un-compensated.
- "Prescription" is often used to describe a person's eye powers, and is typically presumed to be the same as the measure of the eye (refractive state). For eye care providers who provide the "measure of refractive error" as a glasses prescription (which presumes that distance clarity is the objective for their patients), the prescription may indeed indicate the measure of the patient's refractive state.
However, for behavioral optometrists, prescriptions usually have a particular purpose. Typically, this prescription does not simply reflect the patient's refractive state.
What are the types of Refractive State?
Refractive states are classified into four major categories:
- Myopia (nearsightedness),
- Hyperopia (farsightedness), and
- Astigmatism (which is an indication that more than one power is present within a single eye).
- Emmetropia (the natural, neutral eye power for distance), which does not carry a diagnosis of refractive "error."
There are also two descriptors associated with refractive state:
- Anisometropia, which means that the eyes are not the same power as one another.
- Presbyopia, which means that the eyes are less flexible in focusing ability, due to aging.
Can personality tendencies influence eye power?
Who we are, how we think, and how we attend to information very much affects the blood flow at the retina (back of the eye)! This can influence which parts of the eye are most active, and ultimately impact how we develop and grow, along with our use of our visual system. Our tendencies to engage our muscles around the eyes-- whether we squint, or knit our brows together-- are also influencing the available space and flow around the eyes and orbits.
For a behavioral optometrist, a patient's old prescription(s) provides "forensic insight" into how they were functioning in order to develop such a profile of their visual state.
The following habits and personality traits are typical patterns for people who develop a given refractive state:
- Myopes: (Any degree of (-) power; having zero (plano) power is at the cusp of myopia and is a sign of imbalance.) Myopes share a tendency to become very centered and focused on details. They tend to have the ability to hold and maintain attention for longer periods of time when something interests them. They can get so focused on detail, that they may have difficulty "seeing the forest for the trees."
- Hyperopes: Low hyperopia is considered Emmetropia. For people with hyperopia > +1.75 D, their visual system builds in a buffer, so that they must make a conscious choice to engage with their world. A hyperope tends to have an easier time letting go, softening, and seeing the big picture, compared with others. They may need to apply more relative effort to drill down for detail, and they find it more challenging to sustain detail-orientation (whereas a myope can be detail-oriented by default). Lenses for near-point and learning may particularly help these individuals overcome the resistance to reading for extended periods.
- Emmetropes: (Low hyperopia between about +0.25 D and ~ +1.25 D) Indicates a neutral, balanced state, with a general facility for coming in for detail and stepping back for the big picture. Depending on the individual, low-powered lenses may help emmetropes become more efficient when sustaining near-point visual attention, particularly with fine print. When a person with emmetropia starts to shift in their balanced tendencies to focus much more for details, or step back for the big picture, their refractive states may show a shift as well, into any of the other states.
- Astigmatic people: The development of more than one power within the eye can be a very effective flexible maneuver. In small degrees (<1.00 D cylinder), it indicates a tendency to be willing to accept some sacrifice in quality (clarity) for a greater general good. Small amounts of astigmatism may help a person "filter" the way they see the world so that they have an easier time shifting focus between distance and near ("against-the-rule astigmatism," near x 090), or may filter one's view of the world to enhance appreciation for depth and distances ("with-the-rule astigmatism," near x 180). Strong pressures around the eyes, from squinting or from taut eyelids, can cause astigmatism to develop... but releases of pressure can also help that astigmatism to revert back to a lower degree. When people with symmetric amounts of astigmatism develop good binocular skills, they can often maintain very good uncompensated visual acuity, strong binocular skills, and a good ability to "see all sides of a situation." These people may make good mediators and peace-makers, or find themselves negotiating in a family as a middle-child.
- Anisometropes: (>1.00D difference between the eyes is significant, and >1.75D difference can be problematic.) Development of a difference in eye power between the two eyes shows some similarities to the development of astigmatism, but often it results in the sacrifice of binocularity rather than the sacrifice of clarity. Patients with anisometropia may have trouble sharing control, and prefer to have clear roles outlined for who is the leader/ who is the follower. Visually speaking, they may depend more strongly on one eye for detail, and the other eye for spatial awareness. They may sacrifice the quality of binocular vision and depth perception, but gain more flexibility between different kinds of focusing tasks. They may develop a greater dependency on the images they make in their mind as being more trustworthy than the world that they perceive directly. They may tend to understand things more by thinking and logic than by direct experience. Anisometropia is a common trait in fast conceptual learners, who bring a strong will and confidence to their problem-solving skills.
Why do Behavioral Optometrists prescribe glasses?
It's common for eye care providers to "clear" a patient who can see 20/20 unassisted: "You don't need glasses!"
Often, as a functionally-oriented provider, your behavioral optometrist will be inclined to agree with a general eye care provider in these cases: You don't need glasses. However, with attention to a larger volume of information, a behavioral optometrist may yet recommend glasses to provide a particular benefit.
The "need" for glasses typically refers to one's ability to see 20/20, with or without lens-based COMPENSATION.
However, for Behavioral Optometrists, the prescription is a treatment lens, provided to meet a functional objective. Lenses may be prescribed for a variety of reasons, which may be considered independently or in-tandem, such as:
- Compensatory prescription: This makes up for a lack of ability to adjust the eye for clarity at a particular distance. E.g., Distance glasses for people who are nearsighted (myopic); Reading glasses for people who can't change their eye-focus well enough to see at near (farsighted/ hyperopic); Bifocals for people who can't adjust focus between distance and near-point (presbyopic).
- Therapeutic prescription: This approach is more like a facilitator, providing the patient with an opportunity to learn to use their visual skills differently (such as focusing skill, eye-teaming skill, or eye-tracking skill). For example, reading lenses for a child may function like a step stool, helping the child "reach" the reading material so that they can learn the fine control visual skills and depend less on the step stool as they mature.
- Developmental prescription: This might be used to intentionally guide a change in eye power. Conceptually, this is the use of glasses as a "carrot on a stick," providing enough support to benefit the person, while also inviting changes in the balance of power between the two eyes, or in the amount of astigmatism present, or in the degree of near- or far-sightedness. While this may be a greater priority in young patients, slower, intentional changes CAN be made in adulthood.
- Lens-based Postural Therapy prescription: This is the use of lenses to help the wearer change how they perceive space, particularly when the eyes are working as a team. This approach to prescribing can help address postural imbalances ("Abnormal Head Posture"), such as a tendency to tilt the head (often to help with an eye-muscle imbalance), to turn the head (which may favor side-looking, or reduce the need for the eyes to partner as a binocular team). These changes also can carry through to postural changes in the neck/ spine, and into providing a balanced standing posture, and a more balanced moving posture (gait). Dr. Slotnick has been developing techniques and principles to support patients' ability to move with greater freedom, balance, and range of motion. It entails observing the patient in and out of the exam chair, with Sensory Integration between visual, vestibular, tactile and proprioceptive senses. It can even help patients with auditory input imbalances feel more connected to their perception of space and sound.
Lens-based Postural Therapy can be particularly valuable for patients with anisometropia. Binocular vision is the primary organizer of an integrated brain. Visual input from each eye goes to BOTH hemispheres of the brain.
Eye-to-brain and brain-to-eye neurology is not at all like body control over the limbs.
So, when a patient has anisometropia, it suggests that they likely will struggle with facility and freedom of movement, as they typically have a poor ability to visually "pass the baton" from one side of the visual field to the other. If such a patient is fully compensated (has full-eye-power lenses), it usually creates a GREATER conflict which will likely push the person towards INCREASING the amount of anisometropia. This is where a behavioral approach to prescribing can help a patient develop not only greater visual awareness and perceptual skills, but even greater body organization, comfort and balance.
If behavior and personality traits impacts vision development,
can visual changes impact personality and behavior?
Absolutely! This is the central tenet to Behavioral Optometry.
People have a tendency to continue to do what they have always done. So, if they have certain habits and tendencies, and their lenses facilitate the continuation of those habits, who they were becomes who they are... and who they will continue to be.
However, we firmly believe that humans are gifted with the ability to create change for ourselves. We are such a highly adaptable species!
Through Optometric Vision Therapy, we train our patients to become aware of the moment they are in, and learn how to consciously make changes. We do this with visual activities, but we believe this is a life-skill, which transfers beautifully into countless opportunities every day.
A core of our approach to vision therapy and rehabilitation centers around helping patients (children and adults) learn to bring their attention to the PRESENT. It is only in the present moment when changes can really happen, intentionally.
For example: We are very effective at helping myopes release their over-centration and over-fixation habits. They learn the skill of allowing clarity, rather than feeling that they need to drive clarity. As they change their approach, to looking and perceiving, their visual skills improve and their refractive state changes too.
... But does it work?
Dr. Slotnick has been applying these prescribing and therapy techniques to her own visual system, with combinations of passive (lens-based) therapy and active optometric vision therapy at various "teachable moments" over the last 40+ years. This firsthand experience helped her to:
- Reduce her myopia by 7 steps in her more myopic eye (from -3.25 at its greatest to -1.50 over an 18 month period) in her late 20's.
- Reduce her degree of anisometropia, from a 10-step difference (right eye -0.75 and left eye -3.25) to a 6-step difference (right eye +0.25 and left eye -1.25).
- She also gained greater integration of her ability to step back and see the big-picture, while retaining a knack for focusing on details.
- She became more aware of space, her environment, and her ability to appreciate relationships between people, concepts and ideas.
- She continues to explore the interactions between vision and posture, movement, balance and gait, as a firsthand participant. See below for an example of how lenses and filters can directly and immediately change body organization and range of movement!