[Value of anterior chamber lenses in developing countries. Results of a clinical study].

UNLABELLED

There are estimated to be 20 million people blinded by cataracts, 80-90% of whom live in rural areas of developing countries where expert surgical resources are scarce. The majority of all cataract operations are still intracapsular extractions (ICCE). Aphakic correction using spectacles is problematical in developing countries. This study was undertaken to evaluate the safety of multiflex open loop anterior chamber intraocular lenses (AC IOLs).

METHODS

A total of 2000 people attending Lahan Eye Hospital, South-east Nepal, with bilateral cataract were randomly allocated to receive in their first eye either ICCE with AC IOL (AC IOL group) or ICCE with aphakic correction (control group). All operations were performed by two ophthalmologists using a standardized technology and 4.5 x operating loupe magnification. Functional and best corrected vision was recorded. The primary outcome measure was poor vision after surgery, which was defined as a visual acuity of less than 6/60 at 1 year follow-up (WHO definition for severe visual impairment and blindness).

FINDINGS

The median time needed to perform ICCE was 4.1 min and to perform ICCE with AC IOL 6 min. Of all study patients 91% were examined after 1 year. Five percent of the AC IOL group and 5.4% of the control group had a functional visual acuity of less than 6/60. Causes of reduced vision in the AC IOL group versus the control group were: correctable refractive error (22 vs 29), uveitis/secondary glaucoma (13 vs 2), endophthalmitis (4 vs 7), pre-existing eye diseases (4 vs 5), retinal detachment (0 vs 4), and corneal decompensation (0 vs 1). Of the control group, 24 patients were found to be functionally blind in the operated eye (vision < 3/60) because they did not wear their aphakic spectacles. Normal vision (WHO definition: > or = 6/18) was achieved best corrected in 89.9% of the AC IOL group and 93.2% of the control group. Analysis of additional long-term follow-ups (2-5 years post-operatively) has not yet been completed.

INTERPRETATION

This study provides evidence that in developing countries well-manufactured multiflex open loop AC IOLs can be implanted safely by experienced ophthalmologists after routine ICCE, avoiding the disadvantages of aphakic spectacle correction.