Cataracts occur when the natural lens of the eye becomes cloudy, resulting in reduced quality of vision. In cataract surgery, the cataract is removed and replaced with a clear artificial lens, restoring vision. Although cataract surgery is common and widespread, success also depends on the quality of the intraocular lens inserted.

Over the last 20 years there have been significant advances in intraocular lens technology. Better lenses have led to improvements in the quality of vision and visual accuracy – as a result patients see better and need glasses less often after cataract surgery. The latest advancement, and it has been a major one, is enhanced depth of focus (EDOF) intraocular lens technology.

EDOF lenses: Intralenses with increased depth of focus

EDOF lenses are a new generation and represent a significant advance in
intraocular lens technology. EDOF lenses are similar to multifocal lenses in that they allow vision in a wide range of viewing activities. More specifically, they allow: distant vision (such as driving, tennis, golf, watching TV), intermediate vision (reading items on a supermarket shelf, using computers) and near vision for 40 – 50cm (reading, sewing) in good lighting conditions.

This is because while multifocal lenses create multiple focal points, which can be difficult for the brain to adjust to, an EDOF lens creates a single elongated focal point to achieve this wide range of focal lengths.

With EDOF lens placement, the problems of reflections and halos are almost negligible for the patient. It is much more unusual
needing to remove an EDOF intraocular lens from a traditional multifocal lens after cataract surgery. However, there are a few drawbacks to EDOF lenses.

Not all eyes are suitable for an intraocular EDOF. The suitability for placement of an EDOF intraocular lens is based on the health status of the eye and preoperative measurements. Eyes with unusual surface curvature or eyes with other problems, such as age-related macular degeneration or glaucoma, usually do not qualify for EDOF fitting. Also, while EDOF lenses are great for distance and intermediate vision, they may not be as effective for very close distance, especially reading. This is why some patients with intraocular EDOF may need glasses at very close distances.

In conclusion, EDOF lenses are new technology lenses and with their placement, glasses-independent vision is usually achieved after cataract surgery. In other words, they offer distant, medium and functional near vision, in good lighting conditions without increasing the visual disturbances that could be caused by the corresponding multifocal intraocular lenses.

It is written by
Michael Christodoulidis
Eye surgeon
Scientific Associate HYGEIA