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 (ANZRAG, based at Flinders University, Adelaide).
TARRGET aimed to investigate the feasibility of offering free glaucoma screening to immediate relatives of people who have been diagnosed with advanced glaucoma. We hypothesised that relatives of those people severely affected by glaucoma would have higher rates of glaucoma diagnosis than relatives of less severely affected glaucoma patients. The study contacted 100 randomly selected South Australian participants in the ANZRAG to complete family trees of first-degree relatives (parents, siblings and children (FDRs)). These participants were 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 was to attain clinical information to confirm glaucoma status for as many first degree relatives as possible.
In cases where relatives were unable to attend our clinics, or lived too far away, we asked permission to contact their eye practitioner to have clinical information released to the study. If relatives were due to have their eyes checked in the near future we provided them with a form, to be completed by their eye practitioner, so we could have the most recent information.
A summary of the recruitment and screening processes can be seen in Figure 1. Reasons for non-participation by index case included: estranged from family, no living family members, only living relatives overseas and ill health. The study recruited approximately 1.8 family members per index case (person with advanced glaucoma).
It can be seen from the data presented here that 72 of the 131 FDRs screened either had glaucoma or had early signs that need to be monitored carefully. This indicates that if a person has a family member with advanced glaucoma they have up to a 54% chance of developing the disease. Results from TARRGET show that of those thought to be unaffected, for every 4 immediate relatives screened, a new case was detected that will either need close monitoring for the development of glaucoma or was diagnosed as definite glaucoma.
Data collected indicates family members of people with advanced glaucoma appear to have higher than 54% chance of showing at least the early signs of glaucoma. Most of the participants (93%) were aware of their family history, however 17% stated they had not been screened for glaucoma before, with an additional 14% having had an eye health check but unsure if they had been screened for glaucoma. One third of first-degree relatives did not understand how their family history of glaucoma related to their own personal risk of developing glaucoma. Newly detected cases of glaucoma tended to have intra-ocular pressure in the normal tension range, mild visual field defects and cup-to-disc ratio below 0.7 with a similar trend found in new suspects.
As the project transforms to a national study, 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, ongoing, lifetime monitoring is required at least every 2 years. Understanding FDRs perceived risk beliefs and motivations for screening is essential to aid targeting of screening programmes to maximise uptake.
Funding from an NHMRC Partnership Grant, in collaboration with the ANZRAG (Flinders University), Glaucoma Australia, the Lions Eye Institute, the University of Sydney and the University of Tasmania, has enabled the project to become national. The project is running to schedule with 1408 index cases with advanced glaucoma receiving a “Family Tree” form to complete. Index cases are completing and returning the form with the names and addresses of immediate family members. These relatives will receive personalised information regarding their risk of developing glaucoma and important clinical details to show an eye practitioner at their next eye examination. To date, approximately 30% of forms have been returned yielding 1258 first-degree relatives who will receive an information pack from the TARRGET project. This equates to an average of 3 family members available per index case, the same rate we experienced in the pilot study.
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