Dysfunctional Lense Syndrome

Dysfunctional Lens Syndrome (DLS) is a relatively new term that was coined to describe some of the changes that we undergo in our natural lenses with increasing age. When we are under the age of 40 our lens is clear and has good flexibility that allows us to focus for both distance and near. However, as we progress in age we start to lose this flexibility which then manifests as the inability to focus for near thus the need for reading spectacles.

In addition, there is gradual yellowing of the lens that leads to reduction in the quality of vision as well as glare at night and loss of contrast. However, when the vision is checked using good contrast such as black writing on illuminated white background the vision can easily be 6/6 or 20/20. In contrast, cataracts result in decrease vision as well as decrease visual quality.

The 3 stages of Dysfunctional Lens Syndrome are:


Occurs in 40s
The lens loses flexibility and the need for reading spectacles arises.


Occurs in 50s and 60s
There is degradation of the optics of the lens from progressive yellowing and light scatter resulting reduced image quality and glare.


Occurs in 60s and above
The progressive yellowing leads to reduced vision and this is then referred to as a cataract.

(A) Lens in a 20 year old
(A) Lens in a 20 year old
(B) Lens in a 40 year old
(B) Lens in a 40 year old
(C) Cataract in a 70 year old
(C) Cataract in a 70 year old

The three images illustrates the changes in the human lens from age 20 to age 70. In a young patient the lens is perfectly clear (A). As humans age there is progressive yellowing and opacification of the lens. (B) shows changes (dysfunctional lens syndrome) that may be seen in a 40 year old. Further progression leads to cataract (C).

" The key is to choose the right lens for your needs and lifestyle. "

The treatment for DLS is the same as cataract surgery.

Monofocal IOL
These lenses correct only for distance or near. Usually used to correct for distance whether they are shortsighted or longsighted. They will require reading spectacles.

Dr Tint only uses the highest quality monofocal lenses on the market allowing his patients to achieve “HD” quality vision.

Extended Depth of Focus Lens (EDOF) IOL
These are new lenses are designed to give a more seamless visual transition from distance to near. They are a variant of multifocal lenses. One such IOL is the Tecnis Symfony lens. Dr Tint was the first in Edinburgh to implant this lens.

Trifocal IOL
These lenses are designed to all the greatest freedom from spectacles. They focus for distance, intermediate and near. There is a high success rate for total spectacle freedom.

Toric IOL
These IOLs are available in as monofocal, EDOF or trifocal and help to correct astigmatism. They allow for better vision without spectacles.

Blended Monovision
This is a concept whereby the dominant eye is made good for distance whilst the non-dominant eye is corrected to see intermediate/near. The difference between the two eyes are kept as small as needed to allow the patient to blend the two eyes to see both distance and near.