SECURITIES AND EXCHANGE COMMISSION	
Washington, D.C. 20549	
 	
SCHEDULE 13G/A	
 	
Under the Securities Exchange Act of 1934	
(Amendment No. 3)*	
 	
Castlight Health, Inc.	
(Name of Issuer)	
 	
Class B Common Stock, $0.0001 par value per share	
(Title of Class of Securities)	
 	
14862Q100	
(CUSIP Number)	
 	
December 31, 2018	
(Date of Event Which Requires Filing of This Statement)	

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:	
 	
¨	Rule 13d-1(b)	
¨	Rule 13d-1(c)	
x	Rule 13d-1(d)	
 	
(Page 1 of 14 Pages)	
 
______________________________
*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.
The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

CUSIP No. 14862Q100	13G/A	Page  2  of 14 Pages	
 
1	NAME OF REPORTING PERSON
Oak Investment Partners XII, Limited Partnership	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
6,027,622 shares of Class B Common Stock 1	
	6	SHARED VOTING POWER
0 shares of Class B Common Stock	
	7	SOLE DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 1	
	8	SHARED DISPOSITIVE POWER
0 shares of Class B Common Stock	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 1	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
PN	
 	 	 	 	 	
  _____________________
1  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  3  of 14 Pages	
 
1	NAME OF REPORTING PERSON
Oak Associates XII, LLC	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 2	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 2	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 2	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
OO-LLC	
 	 	 	 	 	
  _____________________
2  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  4  of 14 Pages	
 
1	NAME OF REPORTING PERSON
Oak Management Corporation	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
Delaware	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 3	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 3	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 3	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
CO	
 	 	 	 	 	
 _____________________
3  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  5  of 14 Pages	

1	NAME OF REPORTING PERSON
Bandel L. Carano	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
United States	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 4	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 4	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 4	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
IN	
 	 	 	 	 	
 _____________________
4  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  6  of 14 Pages	

1	NAME OF REPORTING PERSON
Edward F. Glassmeyer	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
United States	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 5	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 5	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 5	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
IN	
 	 	 	 	 	
 _____________________
5  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  7  of 14 Pages	

1	NAME OF REPORTING PERSON
Fredric W. Harman	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
United States	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 6	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 6	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 6	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
IN	
 	 	 	 	 	
 _____________________
6  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  8  of 14 Pages	

1	NAME OF REPORTING PERSON
Ann H. Lamont	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
United States	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 7	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 7	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 7	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
IN	
 	 	 	 	 	
 _____________________
7  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  9  of 14 Pages	

1	NAME OF REPORTING PERSON
Grace A. Ames	
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ¨
(b) x	
3	SEC USE ONLY	
4	CITIZENSHIP OR PLACE OF ORGANIZATION
United States	
NUMBER OF
SHARES
BENEFICIALLY
OWNED BY
EACH
REPORTING
PERSON WITH:	5	SOLE VOTING POWER
0 shares of Class B Common Stock	
	6	SHARED VOTING POWER
6,027,622 shares of Class B Common Stock 8	
	7	SOLE DISPOSITIVE POWER
0 shares of Class B Common Stock	
	8	SHARED DISPOSITIVE POWER
6,027,622 shares of Class B Common Stock 8	
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
6,027,622 shares of Class B Common Stock 8	
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES	¨	
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
5.93%	
12	TYPE OF REPORTING PERSON
IN	
 	 	 	 	 	
 _____________________
8  Represents 5,958,872 shares of Class B Common Stock plus options to acquire 68,750 shares of Class B Common Stock.

CUSIP No. 14862Q100	13G/A	Page  10  of 14 Pages	
 
Item 1(a).	NAME OF ISSUER	
 	Castlight Health, Inc.	

Item 1(b).	ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES	
 	150 Spear Street, Suite 400	
 	San Francisco, CA 94105	

Item 2(a).	NAME OF PERSON FILING	
 	Oak Investment Partners XII, Limited Partnership ("Oak XII")	
 	Oak Associates XII, LLC ("Oak Associates XII")	
 	Oak Management Corporation ("Oak Management")	
 	Bandel L. Carano	
 	Edward F. Glassmeyer	
 	Fredric W. Harman	
 	Ann H. Lamont	
 	Grace A. Ames	

Item 2(b).	ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE	
 	c/o Oak Management Corporation	
 	901 Main Avenue, Suite 600	
 	Norwalk, CT 06851	

Item 2(c).	CITIZENSHIP	
 	Please refer to Item 4 on each cover sheet for each filing person.	

Item 2(d).	TITLE OF CLASS OF SECURITIES	
 	Class B Common Stock, $0.0001 par value per share (the " Class B Common Stock ")	

Item 2(e).	CUSIP NUMBER	
 	14862Q100	

Item 3.	IF THIS STATEMENT IS FILED PURSUANT TO Rules 13d-1(b), OR 13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A:	
 
 	(a)	¨	Broker or dealer registered under Section 15 of the Act;	
 	(b)	¨	Bank as defined in Section 3(a)(6) of the Act;	
 	(c)	¨	Insurance company as defined in Section 3(a)(19) of the Act;	

CUSIP No. 14862Q100	13G/A	Page  11  of 14 Pages	
 
 	(d)	¨	Investment company registered under Section 8 of the Investment Company Act of 1940;	
 	(e)	¨	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);	
 	(f)	¨	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);
 	
 	(g)	¨	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);	
 	(h)	¨	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;
 	
 	(i)	¨	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;
 	
 	(j)	¨	A non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);	
 	(k)	¨	Group, in accordance with Rule 13d-1(b)(1)(ii)(K).	

If filing as a non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J), please
specify the type of institution: ___________________________________________

 
Item 4.	OWNERSHIP	
 	The information in Items 1 and 5 through 11 on the cover pages of this Schedule 13G is hereby incorporated by reference.	
 	 	
 	The approximate percentages of shares of Class B Common Stock reported as beneficially owned by the Reporting Persons are based upon approximately 101,652,931 shares of Class B Common Stock outstanding as of November 5, 2018, as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2018 filed by the Company with the Securities and Exchange Commission on November 7, 2018, plus 68,750 shares of Class B Common Stock described below that are issuable upon exercise by the Reporting Persons of options to acquire Class B Common Stock.	
 	 	
 	Oak Associates XII is the general partner of Oak XII.  Oak Management is the manager of Oak XII.  Bandel L. Carano, Edward F. Glassmeyer, Fredric W. Harman, Ann H. Lamont, and Grace A. Ames are the managing members of Oak Associates XII and, as such, may be deemed to possess shared beneficial ownership of the shares of Class V Common Stock held by Oak XII.	
 	 	
 	Amounts shown as beneficially owned by each of Oak XII, Oak Associates XII, Oak Management, Bandel L. Carano, Edward F. Glassmeyer, Fredric W. Harman, Ann H. Lamont, and Grace A. Ames include options to purchase 68,750 shares of Class B Common Stock which may be deemed to be held by Ann H. Lamont on behalf of Oak XII.	

CUSIP No. 14862Q100	13G/A	Page  12  of 14 Pages	

 	By making this filing, the Reporting Persons acknowledge that they may be deemed to constitute a “group” within the meaning of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended, in connection with the securities of the Issuer. Each Reporting Person disclaims the existence of a “group” and disclaims beneficial ownership of all shares of Class B Common Stock or securities convertible into or exercisable for Class B Common Stock other than any shares or other securities reported herein as being owned by it, him or her, as the case may be.	
 
Item 5.	OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS	
 	Not applicable.	

Item 6.	OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON	
 	Not applicable.	

Item 7.	IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY OR CONTROL PERSON	
 	Not applicable.	

Item 8.	IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP	
 	Not applicable.	

Item 9.	NOTICE OF DISSOLUTION OF GROUP	
 	Not applicable.	

Item 10.	CERTIFICATION	 	
 	Not applicable.	

 

CUSIP No. 14862Q100	13G/A	Page  13  of 14 Pages	
 
SIGNATURES
After reasonable inquiry and to the best of his or its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.
DATE: January 28 , 2019
 
Entities:
Oak Investment Partners XII, Limited Partnership
Oak Associates XII, LLC
Oak Management Corporation	 	 	

/s/ Edward F. Glassmeyer	 	 	
Name: Edward F. Glassmeyer	 	 	
Title: General Partner or Managing Member or attorney-in-fact for the above-listed entities	 	 	

Individuals:
Bandel L. Carano
Edward F. Glassmeyer
Fredric W. Harman
Ann H. Lamont
Grace A. Ames	 	 	
 	 	 	
/s/ Edward F. Glassmeyer	 	 	
Edward F. Glassmeyer, individually and as attorney-in-fact for the above-listed individuals	 	 	

 

CUSIP No. 14862Q100	13G/A	Page  14  of 14 Pages	
INDEX TO EXHIBITS
 
EXHIBIT A - Joint Filing Agreement (previously filed)
 
EXHIBIT B - Power of Attorney (previously filed)