# Does coverslip thickness matter for high NA oil immersion objectives?

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

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I am more concerned about the spherical (and maybe chromatic) aberration which would effect the PSF and Strehl ratio. My field of view is very small, 60$\mu$m diameter. –  whoplisp Jul 9 '11 at 22:47