Cataract Surgery & Premium IOL Implants
What is a Cataract?
When cataracts begin to form, the vision becomes increasingly cloudy. Patients with cataract experience reduction in vision, cloudiness of vision, a sensation of a film covering the eye, reduction in the brightness of colours and reduced contrast sensitivity (ability to see shadows of grey).
Early symptoms include also dazzling from car headlights at night and a progressive shift towards short sight, which can interfere with many aspects of everyday activities such as reading, working, driving and playing sports.
Your Questions about Cataracts
What are the symptoms of cataracts?
Typical early symptoms of cataract are light scatter (e.g., dazzle from oncoming car headlights during night driving) and a progressive shift towards short sightedness causing frequent changes in spectacles prescription.
Other symptoms may include:
- Blurred or hazy vision
- Double vision
- Poor vision in bright light
- Seeing halos around lights
- Poor vision at night
- Yellowish tinged vision
What is involved in the cataract surgery procedure?
When the natural lens is removed during cataract surgery it is always replaced with an artificial intraocular lens (IOL) to minimise spectacles use.
Once inside the eye, the IOL unfolds within the lens capsule to lie in the natural position, focusing light accurately on the retina. The small corneal incisions (around 2 mm) are self-sealing, and do not affect the strength of the eye wall.
Complex Cataract Surgery
Complex cataracts have a higher risk of complications during the surgery. The main complication that most surgeons are concerned about is known as a posterior capsular rupture or tear.
The capsule is a thin structure that forms a bag that holds and supports the natural lens and later, the cataract. This bag can tear during surgery.
If this happens, the cataract surgery can be completed safely. However, the torn bag may not be able to support the new lens implant or may allow pieces of cataract to fall deeper into the eye. At this point, a vitreoretinal surgeon such as myself is usually asked to complete the surgery.
During the pre-operative assessment for cataract surgery, ophthalmologists look for features that suggest a higher risk of a posterior capsular tear that include smaller pupils, being on certain prostate medications and previous trauma to the eye. If these are found, a vitreoretinal surgeon is often asked to perform the cataract surgery.
A vitreoretinal surgeon is able to insert lens implants in cases where a cataract surgeon has been unable to do so. This may require special lens implants or techniques that secure the implant to the wall of the eye. This is also the case when a lens implant inserted previously becomes dislocated.
IOL (Intraocular Lens Implant) Choice
Monofocal IOL
Monofocal IOL have a uniform focus and provide excellent image quality but have a limited range of focus.
It is very useful to be able to see clearly at a range of distances after surgery, and surgeons using conventional lenses commonly aim for to minimally spread the focus between the two eyes to achieve a greater depth of focus.
However, reading glasses are normally needed for reading, and a distance prescription may be preferred for some activities – especially in low lighting conditions (e.g. theatre, cinema, night driving).
Trifocals and Extended depth of Focus (EDoF) – Presbyopia-correcting IOLs (Premium Lenses)
These lens implants are well tolerated and provide enhanced spectacle independence, allowing good unaided vision for both distance, computer and reading.
However, whilst premium IOLs produce a greater depth of focus than conventional lenses, there can be a compromise on image quality. Some patients can be troubled by dysphotopsia – light scatter symptoms (e.g. starburst, glare and haloes) and therefore premium IOLs may not be the right choice if you do a lot of night driving.
At your consultation, Mr Dell’Aversana, will be in able to advice you on IOLs choice.
Toric IOLs (for the correction of astigmatism)
Toric IOLs (for the correction of astigmatism) are used to correct astigmatism on the cornea.
Toric IOLs are inserted at a specific position within the eye and are very effective at correcting up to 8 dioptres of astigmatism. Mr Dell’Aversana uses Toric IOL routinely.
Best results are achieved in patients with at least 1.5 D of corneal astigmatism.
Epiretinal Membrane (ERM)
What is an Epiretinal Membrane (ERM)?
The retina is a light-sensitive area at the back of the eye that helps to capture the image. The macula is the name given to the sensitive part of the retina which enables us to see things clearly, such as details, people’s faces and distinguish colours. A Macular Epiretinal Membrane occurs when scar tissue forms over the surface of the macula, the central part of the retina.
How does an Epiretinal Membrane affect my vision?
If you experience symptoms, this may be an indication that the scar tissue is thickening or shrinking, and this results in thickening or wrinkling of the macula. This in turn, causes blurring or distortion of your central vision. For example, reading may become challenging and straight lines may appear wavy.
How is an Epiretinal Membrane Treated?
The only way to treat a Macular Epiretinal Membrane is by having a Vitrectomy surgery. Eye drops or glasses are not effective at improving any vision blurring or distortion caused by the Macular Epiretinal Membrane. During the Vitrectomy, Mr Dell’Aversana makes tiny incisions into the white of your eye (the sclera) and removes the vitreous (the clear jelly) from inside. The eye is filled with a clear fluid as the vitreous jelly is removed. He will then gently grasp and slowly peel away the Macular Epiretinal Membrane from the retina. As the eye recovers from the surgery, vision will slowly improve over the course of several months.
Macular Hole
Macular hole is a defect in the centre of the macula. The macula is a part of the retina (film at the back of the eye) which is responsible for central vision. Symptoms of macular hole include a dark or blind spot in the centre of the vision.
As we age, the vitreous pulls away from the retina. This is called a posterior vitreous detachment. In the majority of population, posterior vitreous detachment will occur with no problem, however, in certain people, it will pull stronger on the retina and form a macular hole.
Only macular holes occurring through all the layers of the retina (full thickness macular holes) will require treatment.
Macular hole can be repaired by surgery called vitrectomy. The surgery is performed usually under local anaesthetic and lasts c. 1 hour. Vitrectomy involves removal of the vitreous, gel-like material inside the eye, via small incisions. This is followed by the treatment to the macular hole and insertion of a gas bubble. You cannot travel by plane until the gas bubble is resolved which can be up to 6-8 weeks. You may also have to keep your head down during the day for a week (with breaks).
The surgical success will depend on the size and duration of the macular hole. The vision improves but may not be perfect like before having a macular hole.
Floaters
The vitreous (a clear and gel-like transparent structure that fills the space in the middle of the eye) liquefies as we get older and the collagen fibres that form it, tend to clump together and float in the resulting fluid. These clusters of fibres can cast shadows on your retina which you see as floaters.
The onset of floaters can be either acute or non-acute (i.e., they develop over time as part of the liquification of the vitreous as we get older). A sudden acute onset of floaters may be a sign of posterior vitreous detachment.
Pvd becomes more common with age, however they can also appear in earlier age with short sightedness, cataract surgery or trauma.
Any patient who experiences a sudden onset of floaters (or they become more numerous or intrusive), flashes of light or a shadow in their visual field, should be examined as soon as possible by a vitreoretinal specialist.
Patients with an acute onset of floaters need to undergo a full retinal examination through dilated pupils t a thorough examination can prevent loss of vision or blindness by acting fast with retinal laser or surgery for a retinal detachment depending, on the location of the tear or detachments, the size and the extent of fluid accumulating underneath the retina.