Hey Safal,

There was a study by Karl Gegenfurtner's group which examined the best fixation target to minimize microsaccades. The best one is a mixture between bulls eye and cross hair. You could use such a target and add some random rotation (e.g. jitter) around the center to avoid accomodation.

Greetings, David

Article What is the best fixation target? The effect of target shape...

interesting.

Thanks David... The paper looks promising.

See also this earlier Ophthalmology paper by Bellmann et al (2004): http://www.sciencedirect.com/science/article/pii/S0161642004009741

Conclusion seems to be roughly the same as Thaler et al (a small cross is best)