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  <xs:element id="isee_MilestoneEventsDomain" abstract="true" name="MilestoneEventsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_PaymentsForLicenseFees" abstract="false" name="PaymentsForLicenseFees" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_ProceedsFromStockOptionsAndWarrantsExercised" abstract="false" name="ProceedsFromStockOptionsAndWarrantsExercised" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_UniversityOfFloridaResearchFoundationUFRFAndUniversityOfPennsylvaniaPennMember" abstract="true" name="UniversityOfFloridaResearchFoundationUFRFAndUniversityOfPennsylvaniaPennMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_PrimaryLicensedProductMember" abstract="true" name="PrimaryLicensedProductMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_SecondandThirdIndicationMember" abstract="true" name="SecondandThirdIndicationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_PublicStockOfferingMember" abstract="true" name="PublicStockOfferingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_AssetAcquisitionClinicalAndMarketingApprovalMilestones" abstract="false" name="AssetAcquisitionClinicalAndMarketingApprovalMilestones" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_AchievementOfSpecifiedCommercialMilestonesMember" abstract="true" name="AchievementOfSpecifiedCommercialMilestonesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_NumberOfProductCandidatesInPreclinicalDevelopment" abstract="false" name="NumberOfProductCandidatesInPreclinicalDevelopment" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="isee_ScheduleOfCompensationCostForSharebasedPaymentArrangementsAllocationOfSharebasedCompensationCostsByFinancialStatementLineTableTextBlock" abstract="false" name="ScheduleOfCompensationCostForSharebasedPaymentArrangementsAllocationOfSharebasedCompensationCostsByFinancialStatementLineTableTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="isee_SustainedDeliveryApplicationsMember" abstract="true" name="SustainedDeliveryApplicationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_AssetAcquisitionMilestonePaymentSharePriceBasisForCalculationTradingDays" abstract="false" name="AssetAcquisitionMilestonePaymentSharePriceBasisForCalculationTradingDays" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isee_BEST1LicenseAgreementMember" abstract="true" name="BEST1LicenseAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_ScheduleOfCommitmentsAndContingenciesTable" abstract="true" name="ScheduleOfCommitmentsAndContingenciesTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="isee_PrivatePlacementUnderwritersMember" abstract="true" name="PrivatePlacementUnderwritersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_StockIncentive2013PlanMember" abstract="true" name="StockIncentive2013PlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardPurchasePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isee_RHOadRPLicenseAgreementMember" abstract="true" name="RHOadRPLicenseAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestWeightedAverageGrantDateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExpectedToVestWeightedAverageGrantDateFairValue" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="isee_IncreaseDecreaseInAccruedResearchAndDevelopment" abstract="false" name="IncreaseDecreaseInAccruedResearchAndDevelopment" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_FirstIndicationMember" abstract="true" name="FirstIndicationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_MilestoneEventsAxis" abstract="true" name="MilestoneEventsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="isee_GAProductMember" abstract="true" name="GAProductMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_AdenoAssociatedVirusMediatedGeneTherapyProgramMember" abstract="true" name="AdenoAssociatedVirusMediatedGeneTherapyProgramMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_UniversityofFloridaResearchFoundationUFRFMember" abstract="true" name="UniversityofFloridaResearchFoundationUFRFMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_CommitmentsAndContingenciesLineItems" abstract="true" name="CommitmentsAndContingenciesLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="isee_C5LicensedProductsMember" abstract="true" name="C5LicensedProductsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_ConcentrationOfSuppliersPolicyPolicyTextBlock" abstract="false" name="ConcentrationOfSuppliersPolicyPolicyTextBlock" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:textBlockItemType"/>
  <xs:element id="isee_AmountToBePaidOnAchievementOfMilestone" abstract="false" name="AmountToBePaidOnAchievementOfMilestone" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_WetAMDProductMember" abstract="true" name="WetAMDProductMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_CARESActMember" abstract="true" name="CARESActMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_WarrantsOrRightsIssuedInTransaction" abstract="false" name="WarrantsOrRightsIssuedInTransaction" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="isee_IncomeStatementAndStatementOfComprehensiveIncomeAbstract" abstract="true" name="IncomeStatementAndStatementOfComprehensiveIncomeAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="isee_SharesIssuedForLicenseFees" abstract="false" name="SharesIssuedForLicenseFees" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="isee_AssetAcquisitionContingentConsiderationArrangementsRangeOfOutcomesValueHigh" abstract="false" name="AssetAcquisitionContingentConsiderationArrangementsRangeOfOutcomesValueHigh" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_ArchemixCorpMember" abstract="true" name="ArchemixCorpMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_LitigationStayPeriod" abstract="false" name="LitigationStayPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="isee_AssetAcquisitionContingentConsiderationArrangementsRangeOfOutcomesSharesIssuableHigh" abstract="false" name="AssetAcquisitionContingentConsiderationArrangementsRangeOfOutcomesSharesIssuableHigh" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="isee_IncreaseDecreaseInWorkingCapital" abstract="false" name="IncreaseDecreaseInWorkingCapital" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_AccruedResearchAndDevelopment" abstract="false" name="AccruedResearchAndDevelopment" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="isee_ShareBasedCompensationArrangementBySharebasedPaymentAwardNumberOfSharesAvailableForFuturePurchase" abstract="false" name="ShareBasedCompensationArrangementBySharebasedPaymentAwardNumberOfSharesAvailableForFuturePurchase" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="isee_UniversityOfMassachusettsUMassMember" abstract="true" name="UniversityOfMassachusettsUMassMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_UnderwrittenOfferingUnderwritersMember" abstract="true" name="UnderwrittenOfferingUnderwritersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="isee_SpecifiedClinicalMarketingApprovalandReimbursementApprovalMilestonesRelatedtoaLicensedProductMember" abstract="true" name="SpecifiedClinicalMarketingApprovalandReimbursementApprovalMilestonesRelatedtoaLicensedProductMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
