DHA cannot improve your visionfatty, but the fatty acid can be very helpful for preventing and treating eye conditions, which will help you protect your vision.
DHA can help prevent forms of retinopathy, when you have something wrong with the retina and the tissue that lines your inner eye. And DHA can also protect your eyes from macular degeneration.
DHA is also called docosahexaenoic acid which is a type of omega-3 fatty acid. Doctors always suggest intake it as it contains abundant of nutrition. However, it does not help any on improving your vision. But keep eating it can make you strong and absorb other benefits. Hope this helps.