The WA Retinitis Pigmentosa Foundation Inc.

Other Retinal Diseases

Usher Syndrome

Usher’s is a genetic condition which causes hearing loss from birth and progressive loss of sight due to Retinitis Pigmentosa.  There are two types of Usher’s.

Usher’s Type 1

• Profound deafness from birth
• RP usually evident within the first 10 years of life
• People with Usher’s Type 1 usually use singing to communicate 

Usher’s Type 2

• Hearing loss ranging from mild to severe
• RP evident from late adolescence to late twenties
• People with Usher’s Type 2 usually use hearing aids and lip read

Although Types 1 and 2 are now well recognized, there is some evidence to suggest that a Type 3 Usher syndrome exists.  People with this type appear to have normal hearing and sight at birth and in childhood.  RP is usually diagnosed between the ages of 20 to 30 years, followed by a degeneration of hearing in adult life.

How do you get Usher’s?

Usher’s is passed on genetically and is a recessive disorder, which means that a person must have two Usher’s genes, one from each parent to get the condition.  A person who has one gene will not develop Usher’s and is called a carrier.  If both parents are carriers, each of their children has a one-in-four chance of having Usher’s.

Stargardt’s Disease

In this condition, the cone cells situated at the macula, deteriorate in function and eventually die.  The rod cells generally remain in tact.  Symptoms usually start at a young age, usually under 20.

People with Stargardt’s disease start to experience difficulty with reading fine handwriting as well as distinguishing colours.  These symptoms progress with age.  In some, this deterioration is rapid, while in others it is much slower.  There is no way of detecting how fast this deterioration will occur in any individual.  By the age of 50, about half will have a visual acuity of 6/60 or worse (see below for definition of “legal blindness”).  People with Stargardt’s disease do not usually have a problem with peripheral vision, and hence usually have little problem with bumping into objects when moving around.  They may however experience difficulties in adjusting to light.

The diagnosis is usually made as a result of deterioration in visual acuity and typical appearances around the macula when the ophthalmologist looks into the eye.  Electrical tests, such as the electroretino am (ERG), electrooculogram and dark adaption testing, can measure the progress of the disease, but are not usually necessary for its diagnosis.

Inheritance of Stargardt’s Disease

Stargardt’s disease is a genetic disorder.  In this situation, both parents are carriers and if their child has Stargardt’s disease, she/he has received one abnormal gene from each parent.  If one child in a family has the disease, it is possible that ¼ of their children will be affected.  The parents are carriers of the disease, but are not affected by it themselves.

Treatment for Stargardt’s Disease

At our current state of knowledge, there is no cure for Stargardt’s disease.  However, research on this and other related diseases, such as Retinitis Pigmentosa, is taking place in Australia and overseas and it is possible that a form of treatment will be available in the near future.

“Legal Blindness”

Legally blind individuals are those whose visual sharpness or acuity (with glass if needed) is 20/200 or worse in the better eye; or whose visual field regardless of visual acuity is restricted to a 20 degree diameter or 10 degree radius.  In Stargardt’s disease, it is the visual acuity which is mostly affected.