I had LASIK five years ago. I was nearsighted; I believe by 6.0 diopteers (20/400, horrible vision unaided). I needed an enhancement 6 months postop.

Over the last year my distance vision has been getting worse. Since I wanted a fresh opinion of my vision I went to a local optometrist who evaluates for refractive surgery and contacts. I was interested in contacts to correct the distance vision. [BTW, he recommended not considering any further surgery until my vision had settled as determined by exams.]

I've tried several soft contacts and the same problem happens. My vision is fine. Then I blink and one eye become blurred. Another blink and that one may become sharp, but the other becomes blurred. When the vision is good it is significantly better than without the contacts. The correction on these is -0.75.

What can this effect be from? Any recommendations on type of lens to try?

The effect is from the lens not fitting well over the ablation zone. Six diopters is a significant amount of change to your central cornea, combined with your peripheral cornea, which remains unchanged.

Standard soft lenses are not designed to fit LASIK'd corneas. The more LASIK you had, the less likely a standard soft or gas permeable lens will fit properly. You see better with the lens because there is some additional correction for nearsightedness. However, for the optics to work consistently, the lens has to drape the ablation zone without deforming. The eyelids deform and reform the lens with every blink, sometimes better, sometimes worse.