SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q/A

(Amendment No. 1)

(Mark One)

For the quarterly period ended June 30, 2013

OR

For the transition period from                      to                     

Commission file number 0-22332

INSITE VISION INCORPORATED

(Exact name of registrant as specified in its charter)

(510) 865-8800

Registrant’s telephone number, including area code

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Sections 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date.

EXPLANATORY NOTE

InSite Vision Incorporated (the “Company”) is filing this amendment no. 1, or this Amendment, to its quarterly report on Form 10-Q for the quarter ended June 30, 2013, or the Form 10-Q, originally filed with the Securities and Exchange Commission, or the Commission, on August 14, 2013. The purpose of this Amendment is to re-file Exhibit 10.1, which was originally filed with the Form 10-Q, to conform such exhibit to comments received from the staff of the Commission on the confidential treatment request filed by the Company with respect to Exhibit 10.1. Confidential treatment has been requested for certain portions of Exhibit 10.1. Omitted portions have been filed separately with the Commission.

This Amendment contains only the cover page to this Form 10-Q/A, this explanatory note, Item 6, the signature page, Exhibit 10.1, as amended, and Exhibits 31.1 and 31.2. No other changes have been made to the Form 10-Q. This Amendment speaks as of the original filing date of the Form 10-Q, does not reflect events that may have occurred subsequent to the original filing date, and does not modify or update in any way disclosures made in the original Form 10-Q.

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Part II OTHER INFORMATION

Item 6. Exhibits.

The information required under this Item appears under the heading “Exhibit Index” of this quarterly report on Form 10-Q.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

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EXHIBIT INDEX

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