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                                                                   Exhibit 10.27

                                 LEASE ADDENDUM

This Lease Addendum refers to that Office Building Lease dated December 12th,
2000, by and between Sierra Pacific Properties, Inc., (hereinafter called
"Landlord") and Ocular Sciences, Inc., a Delaware corporation, (hereinafter
called "Tenant"), of said Premises at Concord Gateway Two, 1855 Gateway
Boulevard, Suite 700, Concord, California.

         l. PREMISES: Suite 700, consisting of approximately 19,828 rentable
square feet.

         2. COMMENCEMENT: The Commencement Date shall be scheduled for January
29th. 2001, or upon substantial completion of tenant improvements by Landlord if
later. Tenant shall have a ten (10) day fixturization period prior to
Commencement Date to install its cabling, office furniture and computers.

         3. RENTAL SCHEDULE: Years 1-3: $2.80 per sq. ft. per month ($55,518.40)
                             Years 4-5: $3.00 per sq. ft. per month ($59,484.00)
                             Years 6-7: $3.10 per sq. ft. per month ($61,466.80)

         4. OPERATING EXPENSES: Tenant's proportionate share is hereby mutually
agreed to be 6.587%. Tenant shall pay to Landlord, as Additional Rent, the
amount by which Tenant's share of Operating Expenses exceeds the 2001 Base Year
as defined and further described in Article 5, "Additional Rent," and this
attached Addendum to Lease.

         5. TENANT IMPROVEMENTS: Landlord shall provide a tenant improvement
allowance of up to $15.00 per rentable square foot ($297,420.00) toward the
construction of the tenant improvements in the Premises. Such tenant improvement
allowance shall include the costs of related architectural, fire code, permit
requirements and fees.

         6. PARKING: Tenant shall be allowed the use of up to fifty-nine (59)
unreserved stalls in the project garage, at no cost during the initial 36 months
of the Lease Term, and thereafter at the then-current monthly market rate in the
Concord Gateway Two parking garage. Landlord reserves the right after the
initial 36 months of Lease Term or any extension or renewal period to increase
the monthly parking fees to market rates comparable with other Concord Class A
office buildings. Landlord reserves the right to convert all or portions of the
garage and Tenant parking to valet parking if usage deems necessary.

In addition, Tenant shall have the right to use up to twenty (20) additional
unreserved stalls on the top level of the project garage on a valet-assist,
first come first served basis, at the current daily rate of $2.00 per car per
day.

         7. OPTION TO EXTEND TERM: Subject to the provisions of this Paragraph
7, Tenant shall have the option ("Option to Extend") to extend the Term of this
Lease for one (1) additional sixty (60) month term (the "Extended Term"), on all
of the same terms and conditions of the Lease except for the monthly Base Rent,
provided that Tenant OR ITS PERMITTED ASSIGN A UNDER PARAGRAPH 23, has
continuously operated its business in the Premises SUBJECT TO EVENTS OF FORCE
MAJEURE AND THE PROVISIONS OF THE LEASE, and provided that no Event of Default
or any even circumstance has occurred (WRITTEN NOTICE OF WHICH HAS BEERS
PROVIDED TO TENANT) which with passage of time or the giving of notice or both
would constitute an Event of Default ("Potential Default") shall exist under the
Lease when Tenant exercises such right or on the commencement of the Extended
Term. Tenant may exercise such right only by giving Landlord written notice of
exercise, submitted by Tenant on Tenant's letterhead stationary, of such right
no later than the date which is six (6) months and not sooner than nine (9)
months prior to the


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expiration of the initial term of this Lease with respect to the Extended Term.
If Tenant fails (or is unable due to an Event of Default or Potential Default)
to timely exercise such rights in accordance herewith, such rights shall
terminate automatically without further action or notice required on the part of
Tenant or Landlord.

Base Rent for the Extended Term shall be that amount equal to the Fair Market
Rental Value for similar space determined as hereinafter provided. In no event
shall the Base Rent for the Extended Term be less than the monthly rent paid by
tenant in the last month of the Original Term.

The term "Fair Market Rental Value" as utilized in this Lease shall mean the
prevailing Fair Market Rental Value of the space in question, on and subject to
the covenants and agreements of this Lease and further based upon the
then-current rent for comparable space in comparable buildings in the vicinity
of the Demised Premises in the City of Concord, such valuation to consider such
comparable buildings as if such are leased on comparable terms as of the
commencement date of the extension in question with those leasehold improvements
then in place as are then contained within the Demised Premises. Such Fair
Market Rental Value shall include prevailing fixed and/or annual increases in
the Base Rent. Calculation of square footage (if any), prorata share (if any),
after-hours HVAC charges, Building hours, and parking allotment ratios and rates
are subject to change during the extended term.

If Tenant gives notice of exercise of option to extend, Landlord shall submit to
tenant in writing of Landlord's proposal as to the applicable Base Rent for the
Extended Perm within twenty (20) days following Landlord's receipt of Tenant's
option notice.

Within ten (10) days of such notice from Landlord, if Tenant should disagree
with Landlord's proposal, Tenant shall so advise Landlord in writing and set
forth Tenant's proposal as to the proper rental to cause rental for the Demised
Premises to be not less than the Fair Market Rental Value. Absent such notice,
Base Rent shall be established at the commencement of such Extended Term as
proposed by Landlord.

If Tenant gives notice of a proposed Base Rent, Landlord may accept Tenant's
proposal by written notice or seek to meet with Tenant in an attempt to arrive
at a mutual agreement as to Base Rent. If Landlord and Tenant, within twenty
(20) days of the date of response by Tenant rejecting Landlord's proposal, shall
not have agreed as to Base Rent for the Extended Term, then the determination of
Base Rent shall be submitted for appraisal as provided below:

         A. If the Fair Market Rental Value is to be determined by appraisal,
within 10 days after the expiration of the 20-day negotiation period, Landlord
and Tenant shall each appoint a qualified M.A.I. real estate appraiser with
experience in the San Francisco Bay Area, and give notice of such appointment to
the other.

         B. Such appraisers shall, within 30 days after the appointment of the
last of them to be appointed, complete their determination of Fair Market Rental
Value based on the standards set forth in the definition of Fair Market Rental
Value stated above, and submit their appraisal reports separately and in writing
to Landlord and Tenant. If the valuations vary, by 5% or less from their
arithmetic average, the Fair Market Rental Value shall be the arithmetic average
of the two valuations. If the valuations vary by more than 5% from their
arithmetic average, the two appraisers shall within 10 days after submission of
the last appraisal report, appoint a third appraiser who shall be similarly
qualified. If the two appraisers shall be unable to agree timely on the
selection of a third appraiser then either appraiser, on behalf of both, may
request such appointment by the American Arbitration Association.

         C. Such third appraiser shall, within 30 days after his or her
appointment, make an independent determination or Fair Market Rental Value
without reference to the reports of the other


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appraisers, and shall submit his or her appraisal report to Landlord and Tenant.
The Fair Market Rental Value shall be as determined by the third appraiser,
unless it is less than the valuation set forth in the lower appraisal previously
obtained, in which case the valuation set forth in the lower appraisal shall be
controlling, or unless it is greater than the valuation set forth in the higher
appraisal, in which case the valuation set forth in the higher appraisal shall
be controlling.

         D. Landlord and tenant shall each pay the fee of their respective
appraisers, and if a third appraiser is required, each party shall pay one-half
of the third appraiser's fee.

         E. Should appraisal not be completed as necessary to determine the
adjustment of Base Rent prior to commencement of the Extended Term, Base Rent
shall be paid each month at the same rate as applicable to the last year of the
initial Term for 30 days, then at the holdover rate specified in Paragraph 8 of
the lease thereafter until adjusted Base Rent is determined, and if an increase
or decrease is found due, the amount of such increase or decrease shall be paid
to the party entitled thereto within thirty (30) days of notice of appraisal
result being furnished to landlord and Tenant, such payment to e for a period
from the commencement of the Extended Term for each monthly rental installation
which became due prior to the date the notice of appraisal result was given.

         8. CONFLICT: This Lease Addendum is an integral part of the Lease
attached. Should there be any conflict in the language between the Lease and
this Lease Addendum, the language of this Lease Addendum shall prevail.

LANDLORD                                     TENANT

Sierra Pacific Properties, Inc.              Ocular Sciences, Inc.
a California corporation                     a Delaware corporation


By:                                          By:  /s/ S.B. Landman
     ----------------------------------           ------------------------------
      Thomas A. Seeno                        Its:  CFO
      President                                  -------------------------------

Date:                                        Date: 1/4/01
      ---------------------------------            -----------------------------
OR

By:  /s/ Albert D. Seeno
     ----------------------------------
      Albert D Seeno                         By:  /s/ J. Fruth
      Director                                  --------------------------------
                                             Its:  CEO
                                                 -------------------------------
Date: 12/20/00
     ----------------------------------
                                             Date: 1/4/01
                                                  ------------------------------
By:  /s/ Douglas W. Messner
     ----------------------------------
      Douglas W. Messner
      Vice President

Date: 12/20/00
      ---------------------------------
By:
     -----------------------------------
      Mark D. Wickham
      Vice President


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