Yes, the situation you described (having received a lawful order from your platoon leader to wear your glasses at all times) could lead to a punitive discharge from the Army. However, there are a LOT of steps between being told to do something and that leading to an involuntary discharge. It is much more likely that continued refusal to obey his order would lead to an Article 15 first.
A couple of elements in your question that should be addressed.
### Can you be ordered to wear your prescription glasses by your platoon leader? Yes .. No .. it depends.
According to the 2024 Manual for Courts-Martial*, a lawful order is one that is not contrary to law, regulations, or a service member's rights and must relate to military duty, which includes all activities reasonably necessary to accomplish a military mission, or safeguard or promote the morale, discipline, and usefulness of members of a command and directly connected with the maintenance of good order in the service.
There are a plethora of situations where such an order would 'check all the blocks' and be given - is your vision such that it impacts on your ability to perform any aspect of your duties if you're not wearing your glasses? Were you involved in an unsafe situation because you weren't able to clearly discern something? Were you not able to perform your duties at some time because "I forgot my glasses"? Is there something specific about your rotation in Europe that makes the situation much different than "home in CONUS"?
The list is endless in making up hypothetical situations where an order given by your platoon leader is a lawful order. However, the other truism in the military regarding orders issued by someone who has the authority to do so - All orders are presumed to be lawful if given by such authority unless proven otherwise.
In other words, if your platoon leader gave you a verbal or written order to do something, which you didn't do, could you get in trouble for it? Yes (Article 90 of the Uniformed Code of Military Justice - Willfully Disobeying a Superior Commissioned Officer).
### Can your Platoon Leader give you an Article 15. No, they don't have the authority. They could recommend that you recieve one (for an Article 90 violation), but it would be up to the Company Commander (or O-3 that has command authority over you) to make the decision if you would receive one or not.
### Can your Platoon Leader "chapter you out of the Army". Again, no, they don't have the authority to do so. To be involuntarily separated, you would have to go the administrative route (AR 635-200*) or the judicial route. In both cases, the one that has the authority to actually separate you is likely your Battalion Commander (or O-5 that has command authority over you) if not higher (depends on what you would be "chaptered out" for).
In the case of the administrative route, they don't throw people out of the Army "for not wearing their prescription lenses when told to do so". They will throw a Soldier out for a pattern of misconduct though.
Now, having said all that, is there a reason you aren't following your Platoon Leader's orders to wear your glasses? You may feel that the order is unfair or intrusive. You could object to the order because it's a chicken**** order and you feel you're being targeted. You could even feel that your Platoon Leaders is a dip**** who's head is so far up their *** that they can see what they ate for breakfast this morning.
YOU may think it has nothing to do with your military duties. Your battle-buddy may think it has nothing to do with your military duties. The free legal advice you get from social media may indicate that it has nothing to do with your military duties.
None of that matters unless it overridden by a superior authority to the one that issued it (i.e., Company Commander) or it is determined that it is not a lawful order by a military judge. As the MCM states, "An order requiring the performance of a military duty or act may be inferred to be lawful, and it is disobeyed at the peril of the subordinate."
Is there any reason you aren't wearing the glasses that you were ordered to wear? Do they cause some sort of medical issue (cause headaches because they are the wrong prescription? cause soreness on your temples because they are ill-fitting? etc.) Do they "cramp your style" because they are Army-issued BCGs and have the fashion appeal of a day-glow orange checkered suit (which, by the way, isn't an excuse to ignore the order)? Was it just a brain-cramp and you forgot?
The bottom line is if you have a legitimate reason for not following the order, then discuss it with your Platoon Leader. If you don't, then wear the damn glasses!
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* 2024 Edition MCM - https://jsc.defense.gov/Portals/99/2024%20MCM%20files/MCM%20(2024%20ed)%20(2024_01_02)%20(adjusted%20bookmarks).pdf
* AR 635-200 (Active Duty Enlisted Administrative Separations) - https://armypubs.army.mil/epubs/DR_pubs/DR_a/ARN40058-AR_635-200-001-WEB-3.pdf
