Can I claim a medical expense that would have been paid by a private plan had it been submitted?

One of my medical expenses would have been fully paid/reimbursed under both my private health plan and my husband's plan had a claim been submitted but now it's past the deadline to claim for reimbursement. Can I claim it as a medical expense since it did not get paid/reimbursed by our plans? The optometrist was supposed to submit the expense to both plans but didn't and by the time I discovered it, it was beyond the time-frame for submitting a claim. Or is it not an eligible expense as it would have been fully paid had the claim been submitted?