ISO TR 22979:2017

ISO TR 22979:2017 pdf free.Ophthalmic implants – Intraocular lenses – Guidance on assessment of the need for clinical investigation of intraocular lens design modifications.
4 Modifications to parent models
4.1 General
IOLs, that are modifications of a parent IOL, have different requirements for clinical investigations
depending on the risk associated with the modifications and depending on their location in the eye.This document provides considerations for the risk assessment to determine the clinical investigation effort that is needed based on the level of modification which is defined in 42.
ISO 13485[iI1 provides requirements for the design and development of medical devices, which are applicable to intraocular lenses including modifications of existing models. The risk assessment and design evaluation are part of the risk management in the design control process in accordance with ISO 14971, and can be used as input for the clinical evaluation. Iso 14971 describes sources for data and information for estimating risks. To determine and evaluate the hazards associated with the modification of IOL models, the manufacturer can additionally use the following sources:
a) clinical data;
b) literature study of equivalent features of similar lOL models. The literature can be general published and unpublished reports, proprietary evaluations and post-market surveillance reports;
c) physical model-eyes, laboratory bench testing or numerical/computational models, which have been verified and validated for evaluation of optical and mechanical behaviour;
d) usability and human factor engineering data resulting from the application of IEC 62366-1[I-Z] or ANSI/AAMI HE75[fl] such as the use of error risk analysis, formative and summative evaluation results, including studies to evaluate surgical manipulation and delivery of the IOL in the eye.
Modifications to the delivery system are subject to the design control process in accordance with
Iso 13485 and factors that pertain to the interaction of IOL and delivery system, as described in
Iso 11979-3, and user interaction during surgery are to be considered in a risk assessment.
4.2 Modification levels
4.2.1 General
Design modifications to parent model lOLs are classified as Level A, B or C. The classification depends on the safety and performance risks that are identified. Examples of risks associated with design modifications are provided in Annex A.
4.2.2 Level A modifications
Level A modifications of a parent model are those for which all safety and performance questions can be adequately addressed without clinical investigation. The modified model is essentially equivalent to the parent model(s). All risks resulting from risk assessment to the modification are adequately addressed by existing clinical evidence. The residual risk will have to be outweighed by the benefits.
4.2.3 Level B modifications
Level B modifications of a parent model are those that raise safety and/or performance risks that can be adequately addressed with a limited clinical investigation of a justified number of subjects followed up for a justified period.
NOTE Typically 100 subjects followed up for 4 months to 6 months. The statistical precision of a 100-subject investigation to detect differences from the safety and performance end points (SPE) ratings is provided in ISO 11979-7.
4.2.4 Level C modifications
Level C modifications are modifications that raise safety and/or performance risks that can only be addressed with a full clinical investigation as defined in ISO 11979-7 and ISO 11979-10.ISO TR 22979 pdf download.

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