What are the other Names for this Condition? (Also known as/Synonyms)

• PERRS (Prolonged Electro-Retinal Response Suppression)
• Prolonged Electroretinal Response Suppression (PERRS)

What is Bradyopsia? (Definition/Background Information)

• Bradyopsia is characterised by prolonged electroretinal response suppression leading to difficulties adjusting to changes in luminance, normal to subnormal acuity, and photophobia
• The disorder is caused by recessive mutations in the RGS9 (chromosome 17q23-q24) or R9AP (chromosome 19q13.11) genes

(Source: Bradyopsia; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Who gets Bradyopsia? (Age and Sex Distribution)

• Bradyopsia is a rare congenital disorder reported in very few individuals thus far
• The presentation of symptoms may begin in early childhood
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Bradyopsia? (Predisposing Factors)

• A positive family history may be an important risk factor, since Bradyopsia can be inherited
• Currently, no other risk factors have been clearly identified for Bradyopsia

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Bradyopsia? (Etiology)

• Bradyopsia is caused by mutations in the RGS9 (chromosome 17q23-q24) or R9AP (chromosome 19q13.11) genes
• The disorder is inherited in an autosomal recessive manner

(Source: Bradyopsia; Orphanet, National Institute of Health and Medical Research (INSERM), Paris.)

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected)

What are the Signs and Symptoms of Bradyopsia?

The signs and symptoms of Bradyopsia may vary among affected individuals in type and severity, and it may include:

• Difficulty adjusting to changes in light intensity
• Light sensitivity or photophobia
• Loss of vision

How is Bradyopsia Diagnosed?

Bradyopsia is diagnosed on the basis of the following information:

• Complete physical examination
• Thorough medical history evaluation
• Assessment of signs and symptoms
• Eye examinations and vision tests
• Laboratory tests
• Imaging studies
• Biopsy studies, if necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Bradyopsia?

The complications of Bradyopsia may include:

• Temporary blinding, while going from conditions of dim light to bright light or vice-versa
• Necessary for assistance during temporary blindness
• Inability to see moving objects under low-contrast conditions
• Severely impaired vision

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Bradyopsia Treated?

There is no cure for Bradyopsia, since it is a genetic condition. The treatment is usually given to manage the signs and symptoms and any complication that develops.

How can Bradyopsia be Prevented?

Bradyopsia may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy), if available, may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders
• Regular medical screening at periodic intervals with tests and physical examinations are recommended

What is the Prognosis of Bradyopsia? (Outcomes/Resolutions)

• The prognosis of Bradyopsia is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Bradyopsia:

• The term “Bradyopsia” was coined by Nishiguchi and fellow-scientists, to imply “slow vision”

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/