Nirmal,

fixing "organs" [regardless whether they are smaller: rodentia - or bigger: human]  after freezing them [="physical fixation"] and storing them at minus 80°C as a whole, then trying to fix chemically [if I understand your problem), embed (?into OCT, paraffin?) and then sectioning for IHC always makes troubles, especially regarding rigidity, distortion.

It would be of benefit to post the complete method(s) you were following already (with no good results).

Just as a proposal to read archived hints on techniques (no warranty for exclusivity or success....(;-()) :

use the search function in/on RG (find the down-pointing arrowhead -- Left mouseclick: find "Questions" click (generates"Search questions" ): insert in the search request field e. g.:  |   fixative  kidney   eye  |

https://www.researchgate.net/search.Search.html?query=fixative%20%20fixation%20%20%20kidney%20%20%20eye&type=question&tabViewId=58fb574ef7b67eed6a5e7002&page=2   and after some second you'll get displayed  a lot of Q&A threads which at least contain the search words....

Especially there are two threads: e.g. https://www.researchgate.net/post/Could_someone_share_a_protocol_for_processing_the_eyeball_for_histological_studies (Verhoeff's fixative and Davidson's fixative)  and perhaps also: https://www.researchgate.net/post/Can_someone_answer_a_question_about_embedding_protocol_for_eye_and_skin    or also:

https://www.researchgate.net/post/Any_ideas_on_how_to_prevent_my_mouse_eye_sections_from_collapsing_when_I_take_a_cryosection?

Best wishes, regards and good luck, WM

Why cryostat? is it that your IHC will only work on cryo OCT sections? If your staining technique allows, you will get "better" morphology with FFPE kidneys and Davidson's fixed eyes. The eyes fixed in Davidson's will retain their shape better than formalin fixed eyes which shrink as a formalin artefact. This then leads to retinal detachment. However you can also detach retina's if you handle the eye too much with forceps. Remove the eye from the orbit with the eyelids attached holding the eyelids with the forceps. Trim off the eyelids after fixation. Please be aware that Davidson's is not as good as 10% formalin for fixing the lens, if that is of interest. Also after 24 hours change the Davidson's fixed tissue into 70% alcohol as prolonged fixation in Davidson's can harden tissue. 

for kidney fixation, you can use 10% buffered formalin.