Acrylic plastic viewports had been in satisfactory use for a number of years. However, the development of testing them by polarised light showed that there are various misconceptions about them. The guidance note on acrylic plastic viewports was initially prepared as AODC 030 in 1986, following advice from Det Norske Veritas (DNV), which sought to correct these misconceptions.

This revised document has been produced by IMCA through the Safety, Medical, Technical & Training (SMTT) Committee of the Diving Division Management Committee as part of the phased review of AODC guidance notes and subsequent re-issue as IMCA guidance. It provides additional guidance on deterioration of viewports as well as identifying a reference document which provides technical criteria and guidelines on the inspection, care, testing and recertification of acrylic viewports.

This document supersedes AODC 030, which is now withdrawn.