Contact lenses are used for those with low vision when there is:
- High refractive error (otherwise, a thick eyeglass prescription),
- therapeutic reasons: such as sensitivity to light and glare, and nystagmus,
- concerns about appearance: to create a more normal look for increased self-esteem, and
- a need for either magnification or field enhancement.
1. Using contact lenses for high refractive error
How contact lenses are beneficial, compare to spectacle lenses:
- wider field of view,
- wider field of fixation, because contacts move with the eye,
- fewer oblique aberrations,
- increased magnification for myopes (those who are nearsighted), and
- contacts can help with eye discomfort relief when using low vision devices, which can be held close to the eye to increase the usable field of view.
While correcting vision with contact lenses may not substantially improve distance visual acuity, especially for those with central vision loss, contacts do hold potential for enhancing vision in the peripheral areas of the retina. These peripheral areas may benefit from a sharper image.
Contact lenses work best for those low vision patients with high myopia, such as those who have pathological myopia. That is because eyeglasses for those with high myopic correction , minifiy the visual field. In other words, the thickness of the eyeglass lenses makes the world appear smaller. Contact lenses, which rest up against the eye, do not create this high level of minification . (Minification: the opposite of magnification.) In some cases, the use of the very thick eyeglasses may contribute to decreased visual acuity.
However, it’s worth noting that nearsighted individuals with near focusing problems or those who engage in a lot of close work may fare better with eyeglass correction.
2. Therapeutic uses of contact lenses for those with low vision and eye disease
- Tinted lenses reduce photosensitivity, glare, and
- reduce eye movements (nystagmus).
Therapeutic Tinted Contact Lenses
Photosensitivity can be reduced or eliminated especially for those with albinism, cone dystrophies, aniridia (those that lack an iris), and achromotopsia.
A small study reported that patients with retinal dystrophies benefited from a red-tinted contact lenses for the reduction of glare and an increase in contrast sensitivity. (Contrast sensitivity is the ability to discriminate objects in an environment.) (Ref: : Red Tinted Contact Lenses
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For example: A child born with achromotopsia(Congenital disease resulting in a severe lack of color discrimination) lacks the ability to see color, is light sensitive, and has poor visual acuity. These children benefited from a red/brown filtered lens which had the result of a slight increase in visual acuity and more comfort, even indoors.
For more information, here is an excellent article at Achromatopsia.info
Albinism and Therapeutic Contact Lenses
Those with oculocutaneous albinism may benefit by using contact lenses three ways:
- Tinted or opaque design lenses helps with glare and light sensitivity,
- Contact lenses are available in high prescriptions. (Reference to the above section on high refractive errors.)
- Contact lenses can also reduce the disruption of vision from the nystagmus, because the contact moves with the eye.
The most common type of specialty contacts prescribed for those with oculocutaneous albinism is a lens with an iris printed on and a clear pupillary center . This lens design cuts down glare entering their very lightly pigmented eye. Case studies have shown that this contact lens with a printed-on iris can decrease light sensitivity. This type of lens is referred to as a prosthetic contact lens.
This printed-on iris also serves to give a more normal look to their eyes.
Contact lenses are the preferred type of correction for nystagmus. Several studies have suggested that contact lenses can potentially reduce the frequency and amplitude of nystagmus, although this remains a topic of debate. This effect may be attributed to the correction of the high refractive error commonly associated with ocular albinism. Additionally, in certain patients, rigid lenses have been found to be more effective than soft lenses.
Contact Lenses to Reduce the Risk for Macular Degeneration and Cataracts
It is common knowledge that eye care professionals often recommend tinted eyeglasses for older patients to minimize UV exposure, aiming to reduce the risk of central retinal damage such as macular degeneration and cataract formation. Additionally, there are clear soft contact lenses available that incorporate UV protection into the lens material.
Commercially available lenses with UV protection:
All ACUVUE® Brand Contact Lenses have Class 1 or Class 2 UV–blocking
Biotrue One Day and Infuse 1 Day (Bausch + Lomb)
ClearSight 1 day, Avaira(Class 1)/ Ray Ban 1 Day (Coopervision)
Biomedics 55 Evolution Aspheric and Biomedics 55 Premier Aspheric (Coopervision)
Each one of these manufacturer’s are careful to point out that there is no scientific data to prove that UVA/UVB contact lens protection will prevent macular degeneration or cataracts, and that wearing sunglasses outdoors is advised.
| FDA Class 1 absorber. Recommended for high exposure environments such as mountains or beaches. The lenses in this classification must absorb more than: | 90% of UVA (316-380 nm wavelengths) and99% of UVB (280 – 315 nm) |
| FDA Class 2 absorber. Recommended for general purposes. These lenses must absorb more than: | 50% of UVA and95% of UVB |
Contact Lenses that Adjust to Different Light Levels for Light Sensitivity
Transitions® eyeglass lenses are the photosensitive plastic eyeglass lenses that change color to a darker ‘sunglass’ tint when exposed to UV light outdoors, and lighten up when entering a space without UV light. This technology has now been incorporated into Acuvue Oasys with Transitions® (Johnson & Johnson Vision Care) contact lenses. Like the eyeglass lenses, these contact lenses adapt to changes in UV light intensity, filter blue light and provide UV protection.
They are also a useful option for computer and digital device users, because the lenses adjust during use of technology that may be throwing off UV and high energy blue light. The long term effects of chronic blue light generating technology on the health of our eyes is not yet known.
Acuvue Oasys with Transitions® contact lenses meet the FDA’s Class I standard by blocking 99.9 percent of UVB and 99 percent of UVA. Additionally, these lenses filter up to 15% of light in the blue light range indoors and 55% outdoors. It is thought that this high energy blue light that has the potential , with long term exposure, to cause damage to eye tissues.
It is a good option for those with eye disease looking to reduce light sensitivity. Keep in mind, while this is an easy option for mitigating some UV exposure, sunglasses should still be worn outdoors.
Contact Lenses that Deliver Medications
Contact lenses have taken on a new role beyond vision correction, now serving as a vehicle for the gradual release of medications over hours or even days. This innovative approach to eye care has made its debut in Canada and Japan with the introduction of the first medication-delivering contact lenses.
One such lens is designed to release an anti-itch medication, offering relief to those suffering from allergic conjunctivitis. By embedding the medication in a thin film along the outer rim of the contact lens, it avoids interfering with central vision. This not only provides targeted relief but also eliminates the need for the daily hassle and potential inaccuracies associated with traditional eye drop instillation.
Initially developed with a focus on a nighttime glaucoma medication known as latanoprost, these lenses pave the way for broader implications in eye care. This novel delivery system holds promise for addressing a range of eye conditions, including macular degeneration, diabetic retinopathy, allergy management, and post-surgical treatments.
Contact Lenses that Monitor Health
Recently approved here in the US is the Triggerfish® CLS (contact lens sensor) (Sensimed AG, Lausanne, Switzerland.) This ‘smart’ contact lens is designed to detect eye pressure changes from the front surface of the eye over a 24 hour period. It is designed to detect relative changes in eye pressure to help predict progression of damage due to glaucoma and determine affectivity of glaucoma treatments.
Interestingly, this small 14.1 mm contact lens has two gauges, a microprocessor and an antenna. The eye pressure changes are relayed by the antenna to a portable recorder carried by the patient.
To read more click here: Sensimed’s Triggerfish
Contact Lenses that Monitor Body Fluids
InWith Corporation along with contact lens manufacturer Bausch + Lomb have created a prototype of a soft contact lens with microelectronics embedded in it to keep tabs on body chemistry, like blood sugar levels or to monitor other electronic body parts. It will derive its energy from the natural blinking cycle of the eye and will send alerts and notifications to a smartphone.
See photos and video on InWith Corp. Facebook page
3. Enhancing Appearance and Self-esteem with Contact Lenses
For many individuals with visual impairments, the reliance on thick, heavy eyeglasses can sometimes amplify the appearance of their eyes, making them appear either significantly large or small behind the frames. Those with substantial eyeglass prescriptions might find themselves wearing what can feel like “coke-bottle” glasses, which, while aiding their vision, can impact their self-confidence.
Contact lenses, while not necessarily providing better vision than glasses, offer a sense of comfort and freedom for those who prefer not to be burdened by the weight and appearance of thick eyeglasses. Even though their vision might remain poor, the switch to contacts can make them feel less conspicuous and less encumbered by their visual impairment.
Furthermore, individuals who struggle with sensitivity to light and glare can discover relief by using-tinted lenses indoors and darker tinted sunglasses outdoors.
The choice to wear contact lenses can be transformative, especially for young individuals with visual disabilities, helping them feel more “normal” and socially accepted by blending in rather than standing out due to their eyewear.
4. How Contact Lenses are Used for Magnification and Field Enhancement
Telescopic contact lenses
This discussion is not about the head mounted or hand-held type of telescopes. The two telescopic systems described here are contact lens plus eyeglasses systems. These are usually calculated and set-up by an optometrists/low vision specialists.
The first system designed for magnification combines a high minus contact lens worn with a magnifying eyeglass lens. This creates a ‘telescope’ lenses arrangement that can give up to 2X magnification. This is a Galilean-style telescope for the optical geeks out there. This contact lens/eyeglass system is best tolerated by younger persons with low vision. It can create some disorientation on head movement vs visual field movement.
How to increase the visual field for those with restricted visual fields; telescopic system:
Reverse contact/spectacle lenses telescopes to increase visual field for those who have severely narrow visual fields, like those with retinitis pigmentosa. In order to increase the visual field, the contact lens is the magnifier(plus lens) and the spectacle glasses (minus lenses) minifies the field so more can be seen.
These solutions utilizing telescopic systems to increase distance acuity or increase distance visual field can be disruptive to vision and will take time to adapt to. As it is one eye that is set up for the telescopic vision and consequently disrupts binocular vision.
At this time, these are the only contact lens-style magnification or field enhancing techniques.
But…there is new technology on the horizon:
Not yet available , researchers in California are developing a contact lens that can zoom in to magnify and out to normal by using blinks.
Another international group is developing a magnifying contact lens that has incorporated fitted mirror surfaces into a telescope a millimeter thick that fits within the contact lens. This contact lens is combined with a set of polarized eyeglass lenses.
Both of these proposed technologies will benefit those who need magnification, especially those with central vision loss, like macular degeneration.
Considerations When Opting for Contact Lenses
Wearing contact lenses, whether for those with low vision or typical sighted individuals, comes with a set of responsibilities that should be carefully considered. Among these responsibilities are:
- maintaining cleanliness,
- proper handling, and
- avoiding over-wearing contact lenses.
For visually impaired individuals, inserting and removing contact lenses can pose unique challenges due to the limitations of poor vision. While it is possible to do so by feel, the difficulty of finding a dropped lens can be a shared struggle, even for those with good eyesight. Additionally, the meticulous care required for cleaning and handling these small, delicate lenses can be daunting for someone with low vision.
The process of getting accustomed to inserting, removing, and caring for contact lenses is time-consuming and requires dedication. However, with sufficient motivation, it can be learned through touch.
It’s important to note that contact lenses prescribed to correct high refractive errors, similar to high prescription eyeglass lenses, tend to be thicker than average. This thickness can lead to discomfort, especially with extended wear.
Specialty lenses, such as those with printed iris rings, require precise fitting to ensure that the tinted ring does not interfere with vision. This often necessitates a fitting by a specialist and may involve a special order rather than an off-the-shelf purchase.
Finally, the issue of contact lens over-wear is a concern for many wearers, both sighted and visually impaired. Over-wearing occurs when lenses are left in for extended periods, often due to forgetfulness, convenience, or a strong preference for contacts over glasses.
Proper adherence to wear schedules provided by the prescribing doctor is crucial to avoid problems and complications. Neglecting these guidelines can lead to infections, redness, allergies, and eventually, an intolerance to contact lens wear. When considering contact lenses, it’s essential to weigh these factors carefully and be prepared for the commitment they require
Interested in learning more…Why those with low vision refused low vision aid
or Comparison of 10 Head-borne Digital Magnifiers for Low Vision
In the end…
It’s important for those with vision impairments to approach the idea of contact lenses with realistic expectations. Contact lenses may not necessarily improve visual acuity, but they offer a range of benefits discussed in this article. Whether it’s addressing light sensitivity and glare, opting for comfort over thick eyeglasses, enhancing appearance, or using specialty lenses for magnification or field enhancement, these are compelling reasons to consider contact lenses. By understanding these considerations, individuals can make informed decisions about whether contact lenses are the right choice for their unique needs and preferences.t.
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