We lease our operating facilities in Mountain View, California, under a non-cancelable operating lease through February 28, 2022. On April 30, 2021, we amended our lease to reduce the portion of the premises leased by the Company and extend the lease term through August 31, 2024. There are no further options or rights to extend the term of this lease.

Our operating lease commitments consist of facility and office equipment leases. Operating lease expense for fiscal years 2021 and 2020 was approximately $1.1 million and $1.3 million, respectively. The weighted average discount rate used in calculating the present value of lease payments was 4.8%. As of January 1, 2022, the weighted average remaining lease term for our operating leases was 2.6 years.

The following represents maturities of operating lease liabilities as of January 1, 2022 (in thousands):

Fiscal Year	Operating Lease Payments
2022	$	1,031
2023		1,084
2024		711
2025		—
2026		—
Total lease payments		2,826
Less: Imputed interest		(170	)
Total future minimum lease payments	$	2,656

Our purchase commitments consist primarily of non-cancellable purchase orders with vendors to manufacture certain components and ophthalmic instruments. Future minimum payments for our purchase commitments as of January 1, 2022 were approximately $18.0 million.

We are obligated to pay royalties equivalent to 1% to 5% of sales on certain products under certain license agreements with termination dates through the end of 2033. Royalty expense, charged to cost of revenues, was approximately $0.4 million and $0.3 million for fiscal years 2021 and 2020, respectively.

We enter into standard indemnification arrangements in our ordinary course of business. Pursuant to these arrangements, we indemnify, hold harmless, and agree to reimburse the indemnified parties for losses suffered or incurred by the indemnified parties (generally our business partners or customers) in connection with any trade secret, copyright, patent or other intellectual property infringement claim by any third-party with respect to our products. The term of these indemnification agreements is generally perpetual any time after the execution of the agreement. The maximum potential amount of future payments we could be required to make under these agreements is not determinable. We have never incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As a result, we believe the estimated fair value of these agreements is minimal.

We have entered into indemnification agreements with our directors and officers that may require us to indemnify our directors and officers against liabilities that may arise by reason of their status or service as directors or officers, other than liabilities arising from willful misconduct of a culpable nature. These agreements also require us to advance their expenses incurred as a result of any proceeding against them as to which they could be indemnified and to make good faith determination whether or not it is practicable for us to obtain directors and officers insurance. We currently have directors and officers liability insurance.

From time to time, we may be involved in legal proceedings arising in the ordinary course of business. In general, management believes that ordinary course of business matters will not have a material adverse effect on our financial position

or results of operations and are adequately covered by our liability insurance. However, it is possible that cash flows or results of operations could be materially affected in any particular period by the unfavorable resolution of one of more of these contingencies or because of the diversion of management’s attention and the incurrence of significant expenses.