What is an IRD?

IRD is used to describe a collection of rare eye conditions that are passed down from parents to children in the genes. IRDs are sometimes also called inherited retinal diseases or inherited retinal degenerations.1

There are lots of different types of IRD. Many are named after the person who first described them. Some names of the more common IRDs are retinitis pigmentosa (RP), Usher syndrome, Leber congenital amaurosis and Stargardt disease.

People with IRD have a mutation in one of the genes responsible for the function of the light-sensitive (photoreceptor) cells in the retina at the back of the eye. In IRD these cells begin to stop working, work less effectively, or die, leading to a gradual loss of vision and blindness.1

There are people of all ages living with an IRD, and it is the main cause of vision loss in people aged 15 to 45 years as well as a common cause of vision problems in children. Although rare, it has been estimated that IRD affects more than 2 million people worldwide (about 1 in every 2000).2

 

Signs and symptoms

There are a range of different signs and symptoms that an IRD patient might experience, beyond problems with vision. These vary because of the number of diseases that are included in the term inherited retinal dystrophy. Below are signs of vision problems that might prompt a doctor to do more tests. This list highlights some of the problems you might see across different types of IRD.

In babies and young children:

  • Nystagmus (uncontrolled eye movements)3
  • Photophobia (sensitivity to light)3,4
  • Poking or rubbing of the eyes3
  • Problems with hearing and balance (mostly associated with Usher syndrome)5

 

In older children and early adulthood:

  • Difficulty reading and seeing things at a distance
  • Loss of visual acuity4
  • Night blindness (nyctalopia) or problems seeing in dim or low light3,4
  • Slow eye response when switching from bright to dim light

 

How is an IRD diagnosed?

There are two types of diagnosis for IRD: clinical diagnosis and genetic diagnosis.6

Clinical diagnosis

This is based on observations of the signs and symptoms you experience as well as tests in the doctor’s office. Its aim is to make a first diagnosis of an IRD, to find out what sort of IRD a patient has and what the likely course of the disease will be.

There are a number of different tests a doctor or ophthalmologist can carry out to see if a patient has an IRD and, if so, what sort it is.7 

Genetic diagnosis

A genetic diagnosis is where genetic testing is used to tell you what gene mutation is causing your IRD. It is used to validate and confirm the clinical diagnosis and find out exactly what is wrong. Not all of the mutations that cause IRD have been identified yet, but a large proportion have and a genetic test provides a complete diagnosis.8,9 You can ask your doctor to organise a genetic test. 

 

References

  1. Retina international 2020 http://retina-ird.org/ Accessed August 2020.
  2. Cremers FRP et al. Genes 2018;9(4):215. 
  3. Kumaran N et al. Br J Ophthalmol 2017;101:1147–1154.
  4. Gill JS et al. Br J Ophthalmol 2019;103:711–720.
  5. Mathur P & Yang K. Biochim Biophys Acta 2015;1852(3):404–420.
  6. Menghini M et al. Expert Opin Orphan Drugs 2020;8(2-3):67–78.
  7. Henderson RH. Paediatrics and Child Health 2019;30:1.
  8. Hafler BP. Retina 2017;37(3):417–423.
  9. Duncan JL et al. Trans Vis Sci Tech 2018;7(4):6.
LUX20-C005l October 2020.
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