Sister Teresa Fernandez had two corneal transplants a few years ago, after the 76-year-old nun suffered tearing, smarting eyes.
Seven of her nine siblings also suffered the same symptoms because a genetic disease called corneal stromal dystrophy runs in her family.
But with the first made-in-Singapore genetic test for the disease, younger members of a family afflicted with the disease can find out whether they have it, and what its progress will be, even if they show no symptoms yet.
The blood test is now being offered to patients at public hospitals, announced its developers yesterday. The first test costs between $500 and $600 but subsequent tests for other family members may be cheaper, they added.
The test scans chunks of a gene called TGFBI for sets of harmful mutations that lead to the disease.
For those with a family history of the disease, it can help predict if they are likely to get it, how fast it will progress and whether they should avoid Lasik vision surgery, which can cause it to flare up.
In corneal stromal dystrophy, proteins clump together in the cornea - a clear layer of tissue at the front of the eye. That clouds the cornea and affects vision. In some cases, patients need corneal transplants. The test was developed as part of the Polaris programme, a national scheme to turn biomedical research findings into treatments for Singapore patients.
Professor Donald Tan, medical director of the Singapore National Eye Centre, which helped develop the test, said the centre operates on 10 to 11 corneal stromal dystrophy patients each year, and has around 200 patients registered in its database.
Polaris programme director Patrick Tan, a senior investigator at the Agency for Science, Technology and Research's Genome Institute of Singapore, said the condition was picked because of the wealth of existing research and expertise on it here. For instance, Singapore researchers have studied the characteristics of the disease and prevalence of various mutations around the world.
While a similar genetic test for mutations is available in the United States, Professor Patrick Tan said the Singapore test is cheaper, and patients here will get support from doctors and genetic counsellors. They will also get their results faster - within two or three weeks - as there is no need to ship samples overseas for testing.
Sister Fernandez said it would be "wonderful" if family members could get tested for the illness. "I think my family is open to having these tests," she said.