Visual Stress Assessments (Colorimetry)

Our Services

Opening Hours

Monday: 9:00am – 5:00pm
Tuesday: 9:00am – 5:00pm
Wednesday: 9:00am – 5:30pm
Thursday: 9:00am – 5:00pm
Friday: 9:00am – 5:00pm
Saturday: 9:00am – 12:00pm
Sunday: Closed


Address: 345 Meltham Rd, Huddersfield HD4 7EH
Phone: 01484 664433

Many people struggle to read and often, it is not due to poor eye sight.

Visual stress is a term used to describe visual discomfort and perceptual distortions in printed text.

It is estimated to be suffered by around 40% of poor readers and 20% of the general population.

Many thousands of individuals who find reading tiring and unpleasant, unknowingly experience visual stress, but there is something you can do about it.

The symptoms can occur despite normal vision and can include:

  • movement of print
  • fading of print
  • letters changing shape or size
  • letters fading or becoming darker
  • patterns appearing, sometimes describes as “worms” or “rivers” running through print
  • illusions of colour – blobs of colour on the page or colours surrounding letters or words
  • rapid tiring
  • headache or eyestrain


  • moving closer to or away from the page
  • becoming restless when reading
  • using finger as a marker
  • skipping words and lines
  • rubbing eyes and blinking excessively
  • low self esteem

We have many patients, young and older, already benefiting from this alternate approach and they have achieved excellent results reporting a significant decrease in their visual symptoms.

The recommended assessment process follows a 3 stage protocol:

Full Eye Examination

It is essential that every individual who struggles to read or believes they may suffer from symptoms of Visual Stress, first undergoes a full eye examination. This is important to rule out any eye health/muscle balance problems. This test is available free of charge for all school aged children, under NHS provision.

Overlay Assessment

Having ascertained that ocular problems are not the cause of symptoms, an overlay assessment is recommended if the issue is mainly for close work. An assessment with overlays may already have been carried out in school. If the school does not use overlays our optometrist can carry out this assessment. The optometrist may suggest the patient use an overlay and return within a few weeks, noting any improvements.

Any improvement in reading speed and accuracy of 15% and above can be considered a successful outcome.

Colorimetry Assessment

Following successful use of a coloured overlay, for a period, the Intuitive Colorimeter is used to assess the patient under the direction of an optometrist, and a precision tint may be prescribed as appropriate. The colour will be specific to each individual’s needs, much more precise than an overlay and very often a different colour to the overlay. Coloured lenses are also much more convenient than overlays for board and computer work.