Preventing Objective Lens Damage: Blunt Force Trauma

[@amribrahim7850]

This Minicourses series are indispensable for microscopes users, particularly for beginners. I'm genuinely grateful for this series being created and looking forward to watch more.

[@Microcourses]

That's great to hear, thanks!

[@sharadatilve]

As someone who trains users in the core to use scopes I try and emphasize on the risk of objective damage. This video gave me great new talking points. Thank you :)

[@Microcourses]

That's great to hear, thank you!

[@DP-qb1zw]

I covered the bottom of my stage petri dish holder with tape so the objective would hit a softer surface if accidentally touching it, plus, it is not fixed to the stage, so it can lift up, too, if touched by the objectives. But, best practice is lowering objectives before changing them.

[@tymothylim6550]

This is very helpful! I learnt a lot from these videos!

[@marcomarcello2538]

Great video, and an invaluable help for facilities during the COVID time in 2020. Thanks Jennifer!

[@555fisch6]

Hello thank you for the nice video. I have a question when you suggest to only "go away" from the object, how do I know how close to get in the first place before that? I know how to make the oil touch our glassbottom dishes and I try to even reuse Z-settings but even then I sometimes struggle to know how close I can get. And I am afraid of scratching the lense which has happened many times but I am very careful so I dont think it was me in our lab. Also I set it and then place the magnettic setting clamps but I am a bit afraid it might push down the glassbottom dishes. What do you think? Best wishes, a first-year Ph.D.

[@6872elpado]

Really interesting video thanks! However I think that breaking the cover slip for a non experienced user might be close to unavoidable. To move away is a good advice, but the problem is with the starting point. You say to move very close for oil immersion, but that "very close" is quite subjective and there is no way for a non experienced user to understand how close the objective is except for gently touching the cover slip. Especially when it is taking a long time to find the focal plane. I think one good advice is to keep the cover slip free to move away from the objective (at least with inverted microscope) in order to see that it gets pushed up when objective is touching. The other way to understand how close the objective is to look at how the oil is spreading and how it gets squeezed. But again that also takes experience.

[@Microcourses]

We've been able to avoid it for many years in my core, since we started training everyone to use this method. It is easier to communicate and demonstrate in person, but there is hope!

[@jonathanvaucher2446]

I purchase a used Zeiss Axioskop 20 and refitted it with Plan-Apochromat DRY objectives. I've always wondered: when you do need to clean an objective lens, what's softest and most appropriate solvent to use (talking about the usual dirt to remove here, not oil, mounting medium or any other special circumstances)? I've seen people use ethanol, methanol, n-hexanes, water from breathing onto the lens, anionic detergents, isopropyl alcohol, Dazzlens solution (i-PrOH and AcOH), pharmacy grade 70% rubbing alcohol... I really need your expert input on this. Is it better to use medical grade cotton swab damped in that solvent or wet lense paper to clean them ? How do you then dry them, dry cotton swab pass or dry lense paper pass ? Plan-apos are fine optics, I really want to prolong their life as much as possible... Thanks in advance for any advice.

[@Microcourses]

For dirt that has settled on a dry lens, first try blowing the dirt off with pressurized air. If that doesn't do the trick and you need to use a solvent, dilute Sparkle (commercial ammonia-free glass cleaner) works well. Lens paper is recommended, as it is the most gentle. This book chapter offers more info on lens cleaning: www.ncbi.nlm.nih.gov/pubmed/24974022

[@caraboutte5502]

This is so helpful, thanks! One question though, isn't it the stage that moves, instead of the nosepiece/objectives, during focusing?

[@Microcourses]

Cara Boutte Hi Cara. I’m glad you found it helpful! It depends on the microscope - some move the stage and some move the nosepiece.

[@melissaglidewell2505]

It can go either way! Some scopes have the ability to move either the stage or the objective/s, in which case you could choose whichever is more appropriate and/or convenient.

[@minicorefacility]

Thanks for the video, I have just embedded this video to my instrument blog which I take full responsibility for both inverted and upright microscopes.

[@Microcourses]

Excellent!

[@SuperSerNiko97]

I believe some people just shouldn't use a microscope

[@Microcourses]

No comment. ;)

[@WastedElephant]

On my regular old compound microscope, I would love to only move the high power lenses away from the slide when focusing. The problem is that I am unable to see the tiny distance from the the slide to the lens. This means I can't safely bring the lens to the slide in order to move it only away while focusing. 🫤