Visual Jargon

This information will help you to put complex visual jargon and measurements into more manageable terms.

A regular eye examination is very important, however getting bogged down with technical terms can make understanding your child’s visual abilities some what difficult. Below are examples of some terminology you may have come across.  

If your child is attending the eye department at the hospital they will encounter different health care professionals at different times.  All departments work together so that your child receives the best care possible.

Vision & Learning

Having a regular eye test and an updated pair of well fitting glasses allows the child to use what vision they have to the best of their ability (See ‘Well fitting frame’).

Vision plays an important part in our lives.  This is especially true when it comes to learning.  If a child has a visual impairment this can hinder the learning process, as teaching and learning is mainly based on visual tasks.  Small steps can help make visual dependant learning easier. Optometrists, healthcare professionals, parents, and teachers must make learning as enjoyable and as easy as possible.  

Any excess effort to see will cause the child to tire more easily and will reduce the thinking power for understanding visual information. Some children’s eyes can’t work together due to different reasons such as amblyopia (lazy eye) or a strabismus (squint) so therefore their depth perception (3D vision) is reduced. 

Another common feature is nystagmus (eyes wobble), this can make fixation difficult, and reduces reading speed.   This extra effort can put increased pressure on the visual system, and subsequently on the child can tire more easily.  This is noticeable towards the end of the day; a nap during school if possible helps.  Quite often this isn’t practical and older children will need a break or a lie down in the evening before starting homework.

You may notice a head tilt or turn when a child is looking at something of interest or trying to concentrate on something visually.  This head position called ‘the null point’ which is unique to them, is adapted subconsciously and shouldn’t be corrected.  It allows the nystagmus movement to lessen and become more controlled in that particular position, thus improving their focus and vision.  Small adjustments can make reading and fixation a little easier such as

  • Placing finger on page of good / high contrast reading material,
  • Clean school black/white board free from glare and dust,
  • Closing blinds on sunny days,
  • Slanted boards for reading.
  • Preference seating (toward front of the classroom)
  • Providing a classroom assistant to help out, flag up problems, or photocopy material into larger print (ask your optometrist / GP/ Ophthalmologist or Social Services about ‘Statementing’).

Importance of a regular eye examination

Lots of useful information can be gathered during an eye test.  The optometrist will make the eye examination as fun and as interesting as possible.  Different letter and picture charts are used, and quite often little lights are shone into the eyes for an eye health and prescription check.

As discussed previously (see accommodation) from time to time drops are required to get a gold standard base line measurement of your child visual function.  The eye drops (cycloplegic drops) can sting for a few seconds, and temporarily remove the eye muscles ability to accommodate (focus) thus as parents you will notice the large pupil, and the child may report some blurred vision.  But these are only temporary and the benefits from an eye test of this kind are vast. This type of refractive eye test is necessary as children’s eyes change a lot as they are developing; but as the child grows they will need the drops instilled less and less.

It is very helpful to bring some dark sunglasses for the way home as this will make things much more comfortable until the effects wear off (12-24 hours later).


  • Contrast Sensitivity

    The direct comparison of one objects colour or intensity to another i.e. a letter chart has black letters on a white background, this gives high contrast; however, for example newspaper can demonstrate poor contrast, with grey writing on a grey back ground i.e. The weather in the UK is fluctuating., resulting in the loss of fine detail. If someone has poor contrast sensitivity it means they can see high contrast objects (i.e. Black buttons on a white coat) however they can’t pick out blue buttons on a blue or busy patterned coat. Quite often individuals with poor contrast sensitivity also have a visual impairment. Poor contrast sensitivity can explain problems at school were reduced quality photocopied examples of work sheets prove difficult to read (even if they are in large print). An illustration of good or high contrast can be seen at some low vision centres were red plug sockets are placed on white walls, this allows some independence instead of a person with low vision trying to locate a white plug socket on a white wall. The same applies to children and games in particular. Using un-crowded / uncluttered pictures will make stories much easier to see and follow. A bright high contrast ball incorporated for games prevents exclusion of a visually impaired child. Parents can sometimes wear bright distinctive clothing, making it easier for their child to pick them out from a crowd. Another helpful feature often over looked is lighting. It is useful to make use of task specific lighting i.e. placing a lamp on a desk to do homework, rather than simply relying on lighting from the main ceiling light bulb in the room. Often optometrists will recommend a good ‘day-light bulb’ and ‘angle poised’ light to increase the visibility and contrast of reading material.