The hydrogel materials can be used to make contact lens implants. Credit: Getty Images

Researchers have synthesised soft hydrogel materials that can be used to make contact lens implants1. These can supply drugs to the retina, the light-sensitive tissue at the back of the eye.

The implants could potentially be used to alleviate the symptoms of diabetic retinopathy, a complication of diabetes that primarily affects the retina, says a team at the Indian Institute of Technology Roorkee in Uttarakhand.

Eye drops are useful to treat disorders that damage areas at the front of the eye, but it is difficult to treat any conditions that affect the back, particularly the retina.

To overcome this, the scientists prepared soft hydrogel lens implants using hydroxyethyl methacrylate (HEMA), polymer of HEMA and chitosan. The team, led by Mayank Goswami, found that all the implants were non-toxic to specific human kidney cells, indicating that they can act as suitable scaffolds or substrates for cell growth.

The chitosan-based implant was the most fragile. The HEMA-based implant closely resembled the structure of a commercial contact lens. It allowed visible light to pass through, suggesting that it could be used for normal vision.

The researchers say the transparency and softness of the implant can be further improved by reducing its thickness during preparation. Next, they want to test the implants’ efficiency in mice by delivering drugs used to heal a damaged retina.