Removal of Retained Lens Fragments
What are retained lens fragments?
During cataract surgery, the natural lens is broken up and removed. In a small proportion of cases (approximately 1 in 200 to 1 in 1000), pieces of the lens may fall through the supporting membrane into the back of the eye, into the vitreous jelly. This is called “retained lens fragments” or sometimes a “dropped nucleus”.
This is not necessarily a mistake by the surgeon - it happens because some cataracts are particularly dense or difficult, and the supporting structures can sometimes be weaker than expected. When this occurs, the cataract surgeon will typically stabilise the eye and refer you to a vitreoretinal surgeon for removal of the lens material.
Why do the fragments need to be removed? Lens material left in the vitreous can cause significant problems:
- Raised pressure in the eye (glaucoma)
- Inflammation inside the eye (uveitis)
- Swelling at the back of the eye affecting vision (cystoid macular oedema)
- Swelling of the cornea
- Retinal detachment
If only a very tiny amount of soft lens material has dropped, it may be possible to manage with drops while the material dissolves. However, if there is significant material, particularly hard nuclear material, surgical removal is usually necessary.
What does the surgery involve?
The operation is a pars plana vitrectomy, performed under local anaesthetic as a day case. The vitreous jelly is removed along with the retained lens material. For particularly dense lens material, I use heavy liquid (perfluorocarbon) to float the fragments forward where they can be removed using an ultrasound probe.
At the end, the eye may be left filled with fluid, or a gas bubble may be used if there are any retinal concerns. Please see the general information on vitrectomy surgery for more details.
What about a lens implant? Whether you have a lens implant depends on how much support remains after the original cataract surgery:
If the capsular bag or rim is intact: A lens can often be placed in the sulcus (just in front of the capsular bag). This is the simplest option.
If there is no capsular support: I use an Artisan lens, which clips onto the back of the iris. This provides stable, long-term support without relying on the capsular bag.
If it is safer to wait: Sometimes it is better to complete the vitrectomy first and return for a second procedure to insert a lens implant once the eye has healed. Temporary glasses or a contact lens can correct your vision in the meantime.
Because the type of lens and the lens placement are not the same as usual, the outcomes of surgery (in terms of how close we get to the desired post operative glasses) are more variable than usual. This means you are more likely to need glasses for distance or near when that wasn't expected or planned.
Risks
Retinal detachment: The risk is higher in eyes with retained lens fragments—approximately 5–10% may develop detachment before or after vitrectomy. This usually requires further surgery.
Raised eye pressure: Usually controlled with drops or tablets.
Cystoid macular oedema: Swelling at the centre of the retina, usually responds to anti-inflammatory drops.
Corneal problems: If the cornea was damaged during the original surgery, it may take longer to recover.
Infection: Approximately 1 in 1000, but serious.
Refractive error: You are more likely to need glasses after surgery than not.
Results
Most patients achieve good vision after surgery. Studies show approximately 60–70% achieve vision of 6/12 (driving standard) or better. However, outcomes depend on pre-existing eye conditions, retinal health, and whether complications develop.
Before surgery
If you have been referred with retained lens fragments, you will usually have been started on drops to control inflammation and eye pressure. Continue these as directed.
Please see the general information on vitrectomy surgery and what to expect after vitrectomy.
During cataract surgery, the natural lens is broken up and removed. In a small proportion of cases (approximately 1 in 200 to 1 in 1000), pieces of the lens may fall through the supporting membrane into the back of the eye, into the vitreous jelly. This is called “retained lens fragments” or sometimes a “dropped nucleus”.
This is not necessarily a mistake by the surgeon - it happens because some cataracts are particularly dense or difficult, and the supporting structures can sometimes be weaker than expected. When this occurs, the cataract surgeon will typically stabilise the eye and refer you to a vitreoretinal surgeon for removal of the lens material.
Why do the fragments need to be removed? Lens material left in the vitreous can cause significant problems:
- Raised pressure in the eye (glaucoma)
- Inflammation inside the eye (uveitis)
- Swelling at the back of the eye affecting vision (cystoid macular oedema)
- Swelling of the cornea
- Retinal detachment
If only a very tiny amount of soft lens material has dropped, it may be possible to manage with drops while the material dissolves. However, if there is significant material, particularly hard nuclear material, surgical removal is usually necessary.
What does the surgery involve?
The operation is a pars plana vitrectomy, performed under local anaesthetic as a day case. The vitreous jelly is removed along with the retained lens material. For particularly dense lens material, I use heavy liquid (perfluorocarbon) to float the fragments forward where they can be removed using an ultrasound probe.
At the end, the eye may be left filled with fluid, or a gas bubble may be used if there are any retinal concerns. Please see the general information on vitrectomy surgery for more details.
What about a lens implant? Whether you have a lens implant depends on how much support remains after the original cataract surgery:
If the capsular bag or rim is intact: A lens can often be placed in the sulcus (just in front of the capsular bag). This is the simplest option.
If there is no capsular support: I use an Artisan lens, which clips onto the back of the iris. This provides stable, long-term support without relying on the capsular bag.
If it is safer to wait: Sometimes it is better to complete the vitrectomy first and return for a second procedure to insert a lens implant once the eye has healed. Temporary glasses or a contact lens can correct your vision in the meantime.
Because the type of lens and the lens placement are not the same as usual, the outcomes of surgery (in terms of how close we get to the desired post operative glasses) are more variable than usual. This means you are more likely to need glasses for distance or near when that wasn't expected or planned.
Risks
Retinal detachment: The risk is higher in eyes with retained lens fragments—approximately 5–10% may develop detachment before or after vitrectomy. This usually requires further surgery.
Raised eye pressure: Usually controlled with drops or tablets.
Cystoid macular oedema: Swelling at the centre of the retina, usually responds to anti-inflammatory drops.
Corneal problems: If the cornea was damaged during the original surgery, it may take longer to recover.
Infection: Approximately 1 in 1000, but serious.
Refractive error: You are more likely to need glasses after surgery than not.
Results
Most patients achieve good vision after surgery. Studies show approximately 60–70% achieve vision of 6/12 (driving standard) or better. However, outcomes depend on pre-existing eye conditions, retinal health, and whether complications develop.
Before surgery
If you have been referred with retained lens fragments, you will usually have been started on drops to control inflammation and eye pressure. Continue these as directed.
Please see the general information on vitrectomy surgery and what to expect after vitrectomy.