University of Edinburgh

Introducing children to Low Vision Aids

Thursday 19 April 2007

Low Vision Aids (1270 until present day)

Mary Dallas RNIB Scotland

Present Day Provision

The Report to the Eye Care Review Steering Group from the Working Group on Children’s Services found in section 6.5 The supply of low vision aids. “There are inconsistencies in the local arrangements for supplying low vision aids to visually impaired children and adults. It is expected that this issue will be addressed in the wider Eyecare Review”.

Eyecare Review

In Annex E Section 8.8 it is stated: “The responsibility for commissioning, supplying and maintaining equipment, technology and low vision aids should be clarified, so that families know what level of service they can expect”.

Annex G of the general review: “Community Optometry Model for the Future” suggests two levels of community-based optometry. Level 1 was introduced on 1 April 2006 as part of the revision of General Ophthalmic Services.

Level 1 Ophthalmic Services

  • Free eye health check
  • External examination of the eyes by slit lamp biomicroscopy
  • Internal examination with slit lamp biomicroscopy (with dilation and condensing lens where necessary)
  • Assessment of pupil reflexes and extra ocular motor function
  • Supplementary tests as required to ensure an accurate diagnosis (repeat/additional procedures)
  • Diagnosis and treatement of commonly occuring eye conditions up to referral to level 2 management or a care pathway
  • Measuring intra-ocular pressure when clinically necessary by applanation tonometry
  • Automated perimetry when clinically necessary
  • Refraction and muscle balance tests
  • Prescribing of optical aids
  • Direct referral for ophthalmological or orthoptic assessment
  • Maintenance of appropriate clinical records including a full data set of findings

Level 2 Ophthalmic Services

This would require some additional training and would be delivered in the community, in audited practices by accredited optometrists.

Key Components

  • The capacity for the primary management and treatment of many common eye conditions by Optometrists within their scope of practice.
  • The safe management of a wide range of external/anterior eye conditions.
  • The co-management of chronic eye diseases such as glaucoma, cataract, diabetes, macular degeneration and dry eye disease.
  • The development of community Low Vision networks.
  • Accurate and effective diagnosis and ongoing treatment of children with strabismus.
  • Option as an entry point for access into Eyecare pathways.

Why Do We Use LVAs?

  • To improve visual functioning
  • To allow the person with a visual impairment to be as independent as possible.

The use of LVAs is dependent on many factors

  • Type of vision loss
  • Degree of loss
  • Persons light and glare needs
  • Ability to handle and operate the aid

Optical Aids

  • Optical aids are made up of lenses placed between the eye and the object to be viewed.
  • Objective is to get the maximum potential vision from the particular aid described.
  • Magnifiers have different strengths and sizes.
  • The bigger the size of the magnifier lens, the weaker it will be.
  • More powerful magnifiers are smaller and have to be held close to your eye and what you want to look at.
  • The “magnifying power” is usually denoted with an “X” to mean “times” eg; X8 is eight times.
  • The lens power is measured in dioptres (D).
  • Magnifying power of a plus lens is obtained by dividing the number of dioptres by 4
  • The reading distance in centimetres, that is, the distance between the text and the lens can be obtained by dividing 100 by the number of diatropes.

Optical Aids for Looking at things close up

  • Hand-held magnifiers. Available in strengths from 1.5 times to 10 times. Some are fitted with lights. Some have a battery operated light
  • Stand magnifiers. Used for reading and sometimes writing. Good if person has shaky hands. Available in strengths from 2 times to 20 times. Some are fitted with lights
  • Pocket magnifiers. These are ideal for taking out and about to places like shops. Available in strengths from 2 times to 15 times.
  • Spectacle mounted magnifiers. These leave hands free. They either have very strong lenses, which are thicker then normal lenses or they have telescopic lenses that stick out from the spectacles’ frames. Objects have to be held much closer to the eye than normal. Can be used by one or both eyes.
  • Video Magnifiers.

Optical Aids for Looking at objects in the distance

  • Monoculars. These are like mini- telescopes through which you look with only one eye. The majority are hand held, although some of the weaker ones can be mounted onto spectacles. Strengths range from 2.5 times to 14 times. Good for football matches, television, looking at road signs or numbers on buses.
  • Binoculars. With these you use two eyes.

Absorptive Lenses

Absorptive lenses regulate the amount of light transmitted through to the eye and can often be worn over prescription glasses. By eliminating harmful sunrays, reducing glare, increasing contrast, and helping with the transition between light and dark surroundings, these lenses can increase both comfort and safety.

Non-optical Aids; Non-optical aids are environmental factors

Make things brighter and easier by better lighting

  • Cut out glare
  • Make things bolder with good contrast
  • Think about auditory considerations
  • Put up clear signage
  • Put edgings on steps and stairs.

This list is not definitive.