6. Commitments and Contingencies Operating Lease Commitments. Our operating lease commitments consist primarily of our facility lease and various office and computer equipment leases. Operating lease expenses for the nine months ended September 28, 2019 and September 29, 2018 were approximately $1.0 million. The weighted average discount rate used in calculating the present value of lease payments was 5.4%. As of September 28, 2019, the weighted average remaining lease term for our operating leases was 2.5 years. The following represents maturities of operating lease liabilities as of September 28, 2019 (in thousands): Fiscal Year Operating Lease Payments Remainder of 2019 (3 months) $ 381 2020 1,550 2021 1,539 2022 317 2023  Total lease payments 3,787 Less: Imputed interest (248 ) Total lease liabilities $ 3,539 Purchase Commitments. Our purchase commitments consist primarily of non-cancellable purchase commitments with vendors to manufacture certain components and ophthalmic instrumentation. As of September 28, 2019, our future minimum payments through fiscal year 2020 for our purchase commitments was approximately $6.2 million. Indemnities. We enter into standard indemnification arrangements in the 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 that 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 minima l. 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. Legal Proceedings . From time to time, we may be involved in legal proceedings arising in the ordinary course of business. Although the results of litigation and claims cannot be predicted with certainty, we currently believe that the final outcome of these ordinary course matters will not have a material adverse effect on our business, operating results, financial condition or cash flows. Regardless of the outcome, litigation can have an adverse impact on us because of defense and settlement costs, diversion of management resources and other factors.