In my opinion, each lysis buffer is able to damage the spermatids/spermatozoa. I suppose be forbearing and search gently under the microscope between the erythrocytes.
Thank you for your answer Pavel Travnik. But for some cases with very low count of spermatozoa, RBC lysis solution is very helpful. We have used it for more than 250 cases in Turkey and we did not face any major problem. Now I am planning to use it in UAE.