Low Vision Aids
A significant visual impairment that cannot be corrected fully with glasses, contact lenses, medication or eye surgery is termed as low vision. It is caused by severe eye disease, in which visual acuity in the better eye is 20/70 or less, or where there is a significant loss of visual field (constriction to 20 degrees or less, termed tunnel vision).
Visual acuity of that a person with 20/70 vision who is 20 feet from an eye chart sees what a person with unimpaired (or 20/20) vision can see from 70 feet away. Low vision can impact people of all ages, but it is associated primarily with adults over the age of 60.
Causes of Low Vision Aids
Causes and typical patterns of low vision which cannot be corrected include:
- Blurred or partially obscured central vision: Macular degeneration (both, age-related, and hereditary)
- Blind spots, blurriness and visual distortions: Diabetic retinopathy
- Poor peripheral vision, or tunnel vision: Glaucoma
- Poor peripheral vision, and inability to see in the dark: Retinitis pigmentosa
- Eye injuries
- Poor central vision which may progress to no light perception: Optic neuropathies which may be inherited or acquired (toxic)
Low Vision Aids
Magnifying spectacles are worn like eyeglasses, and help you see better for tasks like reading, threading a needle, stitching etc. These are hands-free magnifiers, allowing you to work with your hands.
These magnifiers are placed away from your eye, on the object you are trying to read. The handheld versions are also available for reading, and these usually have built-in lights. In case you have a tremor or arthritis, stand magnifiers are best suited for you.
Telescopes may be attached to eyeglasses or be like binoculars, and are used to see objects or signs far away.
These electronic devices make printed pages and pictures look bigger. The cheapest available “video magnifiers” are the smartphones and tablets that allow you to increase contrast and font size of texts.
Low Vision Techniques
Increase the lighting in your house: Replace light bulbs with bulbs of higher wattage, and make all nooks and crannies are adequately illuminated to prevent falls and improve visibility.
- Reduce glare: Adjust light fixtures to minimise Shield your eyes from dazzle by wearing sunglasses and a wide-brimmed hat or a dupatta/ stole wrapped around your face shielding your eyes.
- Use heavy, bold felt tip markers for writing and shopping lists: Use a whiteboard to mark essential dates and calendars.
- Special low vision devices: Watches, remotes, and thermostats that “talk back” are also readily available, and affordable.
A visit with an expert in the Clinic low vision specialty group will include the following:
- Low vision assessment :A medical social worker will interview you to determine how low vision is affecting you and your family.
- Comprehensive vision exam :You may already have received an eye exam from an eye doctor, but during a visit with the Clinic low vision specialty group, a doctor will give you an extended, refined vision exam. This exam helps pinpoint which lenses or low vision devices will help you achieve the clearest possible image.
- Follow-up and referral : You may be referred to an occupational therapist for training in the use of low vision aids, or the medical social worker can refer you to agencies or organizations in your area that help visually impaired people.
Frequently Asked Questions
In advanced cases there is a complete loss of sight and lens becomes pearly white in colour.
If you experience any of the following issues, schedule an appointment with your eye doctor immediately:
- Cloudy or blurry vision
- Double vision (diplopia)
- Fading of colours
- Seeing halos around lights
- An increased sensitivity to glare
- A distortion of vision that makes objects appear as if you’re looking at them through a veil.
Cataracts are the world’s leading cause of blindness, accounting for approximately 42 percent of all cases of blindness in all the countries, luckily its easily treatable in the present age through a simple surgery.
Some infants are also afflicted by cataract, which is caused as a result of infections during pregnancy. The disorder can also be a symptom of metabolic disease affecting the body’s processing of carbohydrates, amino acids, calcium or copper among infants and young kids. If left untreated, cataracts might also lead to blindness.
You may go home with an eye pad and shield, or just a shield. The pad can be removed after the first hour. The shield should be worn at night for the first week.
The eye may feel gritty, and sometimes you may experience some mild headache. These symptoms are common. The discomfort should rapidly improve over the next 24 hours. There should be no worsening of your symptoms. If your discomfort or a headache should deteriorate, you should contact your doctor immediately.
Your vision will normally be much better on Day 2. Sometimes there can be some blurring or misting in the eye, but this should improve over the course of the day. If you feel your vision is becoming more blurred, contact your hospital immediately.
If you take part in a sport that risks a poke in the eye, you should discuss returning to these activities with your surgeon before the operation. You should not go swimming for the first 2 to 4 weeks to minimize the risk of infection. When cycling in the first few weeks following surgery, keep your sunglasses on to reduce the impact of dust.
Jobs that are more physically demanding and involve exposure to liquids or dust might require a more graduated return to full activities, but are best discussed with your surgeon.
You may opt to choose for lenses which provide you vision for distance and near. In such cases, dependency on glasses is reduced.
Routine surgery can only correct the spherical component of the eye leaving behind the cylinder power which has to be later corrected by additional prescription glasses.
With advancements in surgical techniques and IOL (artificial lens) designs, today both spherical and cylinder components of the eye can easily be corrected with the highest precision.
The cylinder component in Cataract Surgery can be corrected by three ways
- LRI or Limbal Relaxing Incisions: In this technique, a Femto Laser is used to give highly precise incisions at the periphery of the cornea to induce cylinder correction. Since these incisions are given by a laser, it can only be coupled with a Femto Cataract Surgery.
- Toric Lenses with Verion Digital Axis Marking: Toric lenses are special lenses which have both cylinder, and spherical component build in one lens. Since cylinder axis varies in individual eyes, the lens has to be aligned to the specific axis of the individual. In such cases, even a minor deviation from the original axis can cause significant disturbance in final visual outcomes. Now with the introduction of Verion Digital Axis Marking system, these toric lenses can be aligned with outmost precision, up to 1 degree.
- Toric Lenses with Manual Marking: As discussed above, the final visual outcome in a toric lens depends on how precisely it is aligned to the original cylindrical axis of the eye. Since the manual markings cannot be as precise as digital markings, the manual system may give slightly inferior results compared to the digital system.
Dr. Shweta Jain
Dr. Rajiv Mohan
Dr. Sanjiv Mohan
MS from Dharwad university, Belgaum.
Trained for higher surgical training in Scotland U.K for 2 years.
Experience: Dr. Sanjiv Mohan has an experience of over 18 years as an Ophthalmologist”
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