TARRGET Study Report
Targeting at risk relatives of glaucoma patients for early diagnosis and treatment
The Targeting At Risk Relatives of Glaucoma patients for Early diagnosis and Treatment (TARRGET) study is a partnership project between Glaucoma Australia and the Australian and New Zealand Registry of Advanced Glaucoma (based at Flinders University, Adelaide).
TARRGET aims to investigate the feasibility of offering free glaucoma screening to immediate relatives of people who have been diagnosed with advanced glaucoma. We hypothesise that relatives of those people severely affected by glaucoma will have higher rates of glaucoma diagnosis than relatives of less severely affected glaucoma patients. The study has been contacting 100 randomly selected South Australian participants in the Registry of Advanced Glaucoma to complete their family trees of immediate relatives (parents, siblings and children). These participants have been invited to ask their immediate family if they would be willing to come to the Repatriation General Hospital or Flinders Medical Centre in Adelaide for a free, comprehensive glaucoma examination. Our aim is to attain clinical information to confirm glaucoma status for as many first degree relatives as possible.
In cases where relatives are unable to attend our clinics, or live too far away, we have asked permission to contact their eye practitioner to have clinical information released to the study. If relatives are due to have their eyes checked in the near future we have provided them with a form, to be completed by their eye practitioner, so we may have the most recent information.
As of June 2016, 76 families have agreed to take part in the study with 104 immediate relatives screened so far (see Table 1). Reasons for non-participation have included: estranged from family, no living family members, only living relatives overseas and ill health. The study is currently recruiting approximately 1.4 family members per index case (person with advanced glaucoma).
Table 1: TARRGET recruitment results
|Families Taking Part||76|
|Immediate Relatives Enrolled||104|
|Immediate Relatives Screened||86|
|New Glaucoma Case Detected||3|
|New Glaucoma Suspect Detected||13|
|Previous Diagnosis of Glaucoma||19|
|Previous Glaucoma Suspicion||7|
|Nil Glaucoma Detected||38|
|Screening to be Reviewed by Ophthalmologist||5|
It can be seen from Table 1, that 42 family members of the 86 screened either have glaucoma or have early signs that need to be monitored carefully. This indicates that if a person has a family member with advanced glaucoma they may have a 50% chance of developing the disease.
Early results show that for every 5 immediate relatives screened, a new case is detected that will either need close monitoring for the development of glaucoma or will be diagnosed as definite glaucoma. Some families have yielded more than the average number of family members who agree to be screened. Four members of the AG1270 family consented to be screened and during this process the TARRGET study detected a new glaucoma suspect (see Figure1). This family member could not remember if he had had his eyes checked for glaucoma before, but was aware that glaucoma could be inherited. As part of the TARRGET project he has now been informed of his status and has been provided with important information that could save his eyesight.
Figure 1: Family AG1270
Data so far indicates family members of people with advanced glaucoma appear to have a 50% chance of showing at least the early signs of glaucoma. As the project unfolds, we will look to advocate for better screening pathways for these individuals. This may involve lobbying for altered Medicare structures for nerve fibre layer testing and ongoing screening of family members.
An important part of this process has been to realise that family members often feel that after one “normal” test they are cleared of the risk of glaucoma. In fact, as an ageing disease, lifetime monitoring is required at least every 2 years.