Does anyone here have firsthand experience with processing mouse retina to visualize Outer segment morphology with SEM?

I am using the below protocol without the tannic acid. Is the tannic acid a critical component for SEM of OS?

After fixation, sample pieces were washed with 0.1 M sodium cacodylate buffer 3 × 15 minutes and repeatedly impregnated with 1% OsO4 and 1% tannic acid to increase bulk electron conductivity as well as to prevent damage and imaging artifacts (Paper: Early Onset Ultrastructural and Functional Defects in RPE and Photoreceptors of a Stargardt-Like Macular Dystrophy (STGD3) Transgenic Mouse Mode).

Also saw a protocol that uses 2.5% glutaraldehyde, 0.1 M cacodylate sodium buffer, 2% sucrose (pH 7.4) for 6 h as a fixation prep (paper Rhodopsin Signaling and Organization in Heterozygote Rhodopsin Knockout Mice). Why the sucrose?

Really needing help,

Thank you guys so much,

Lily :D