This question is related to Impact of covering glass on lens performance.
I use a 63x TIRF objective with a numerical aperture of 1.46 and oil immersion. The immersion oil has an index of $n_e=1.518$. I'm observing green eGFP fluorescence at around 510 nm. Does it matter if I use a coverslip (BK7 glass) with 140 $\mu$m thickness instead of 170 $\mu$m?
Edit: The objective is a Zeiss Objective alpha "Plan-Apochromat" 63x/1.46 Oil Corr M27