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Doctors have believed that childhood blindness, known as Stargardt disease type three, occurs when the long chain fatty acids are missing in the photoreceptor cells are missing. The lack of this chain causes children's eyesight to worsen for several years before they succumb to blindness. A recent study, however, found evidence that this chain might not be responsible for childhood blindness after all. The study published in PNAS suggests that research behind childhood eyesight might need to be restarted.

The idea that Stargardt disease resulted from the lack of the chain originated from the discovery of a particular gene mutation. Stargardt disease has three different types, each one resulting from a particular gene mutation. The third type results when the mutation prevents the long chain of fatty acids from synthesizing, which led researchers to believe that this lack of fatty acids caused blindness. However, actually proving that there is a direct cause between the two is difficult.

Lead researcher David Krizaj PhD and first author Peter Barabas PhD experimented with mice by breeding mice without the particular chain. The researchers specifically removed the ELOVL4 gene that is responsible for creating the long chain of fatty acids only in photoreceptor cells. The amount of fatty acids was reduced up to 90 percent. They found that even without the long chain, mice did not develop blindness. Barabas is a postdoctoral fellow at the John A. Moran Eye Center at the University of Utah.

"If it's not the loss of fatty acids causing the disease, then we'll have to find other strategies to help these kids," Kirzaj, who is an associate professor of ophthalmology and visual sciences at the center, said.

Although the researchers were able to disprove the causal link between the chain and type three Stargardt disease, they did not find out what causes the disease. However, they theorized that the gene mutation might be causing blockage around the photoreceptor cells, causing them to react as if they were dead.

This study opens up research into type 3 Stargardt disease. If researchers continue to try to find the causes behind it, they might be able to find a cure or better treatment options for children. However, right now, the causes of the disease remain unclear.