Use of intraocular lenses in cataract surgery in developing countries: memorandum from a WHO meeting.

Visual loss or disability from cataract represents a massive public health and socioeconomic problem in most developing countries. At present, some 13.5 million cases require treatment and this number will increase, as most countries in the Third World are unable to cope with both the backlog and new cases. Cataract extraction with intraocular lens (IOL) implantation is now the established and preferred method in industrialized countries. The introduction of IOLs in developing countries, however, depends on their having adequately trained manpower and facilities (equipment and supplies, including IOLs) for surgery. This will inevitably increase the cost per operated case which, despite the scarce resources for cataract surgery in many developing countries, may be justified by the improved restoration of the patient's vision. Experience has led to the following generic designs for IOLs: the one-piece or three-piece C-loop polymethylmethacrylate (PMMA) posterior chamber lens, which is the current favourite; and, the flexible or rigid one-piece all-PMMA anterior chamber lens, which is a valid alternative in many situations. Further scientific evaluation of the use of these lenses in a wide variety of settings in developing countries is required. Operations research is also needed in order better to define and standardize the various steps and procedures in the surgical and post-operative management of IOL implantation in Third World settings. Meanwhile, the following should be available to ensure safe and good quality cataract surgery using IOLs in developing countries: properly trained surgeons; the needed facilities and equipment with regular supplies; a good quality lens of appropriate design; and the necessary means for careful follow-up of operated patients.