I think the first step is to eliminate the resistor commonly used to limit current and replace that with electronically limited current. The second might be to select LEDs with a very narrow spectrum of light, so only a single crystal is involved with the light generation. Third is to also select a LED with epoxy covering that does not distort or spread the emitted light.
And 4th might be to create circuit boards for your SMD LED with all associated circuitry on that board and minimal distance between the LED and the other circuitry.
Only when you reach the limits of your project, think of driving the LED with an IC that can reverse polarity, whatever that device might be.