Intraocular lens treatment is a procedure in which a special artificial lens is placed in the eye in place of the natural lens.
While it is primarily a treatment for cataract, it may also be preferred in suitable candidates to free patients from glasses in refractive errors.
Who Can Have Intraocular Lenses?
Intraocular lens surgery can be performed in patients with cataract or with a severe refractive error who do not have a corneal thickness suitable for laser treatment.
The patient’s suitability for intraocular lenses is decided after a detailed eye examination.
Considerations When Choosing the Lens to Be Used
Intraocular lenses come in different qualities and characteristics according to their optical properties, the materials they are made of and their shapes. The appropriate lens is determined by taking the patient’s needs, age and habits into account.
Having your surgery performed at a reliable institution such as the Eye Foundation is very important in terms of the material, quality, compliance with standards and sterility of the lens used.
How Is Intraocular Lens Surgery Performed, and How Long Does It Take?
For the procedure, the eye is anaesthetised with anaesthetic eye drops. General anaesthesia is not required. After the eye is numbed, the appropriate artificial lens is placed inside through a small incision in the cornea. The procedure ends with the application of an antibiotic eye drop.
If both cataract and refractive error are present, both can be addressed in a single session. Surgery on one eye takes around 15 minutes on average. If both eyes are to be operated on, separate days are preferred. There is no need to stay in hospital after surgery.
Post-Operative Recovery
After surgery, special protective glasses are worn to protect the eye. If no oedema develops in the cornea, the patient begins to see normally within 1–2 days. Antibiotic and corticosteroid eye drops, together with artificial-tear drops, should be used as prescribed by the doctor and for the recommended duration.
Unless the doctor advises otherwise, the operated eye is usually checked the day after surgery, after 1 month and after 3 months.
Types of Intraocular Lenses
Intraocular lenses differ according to their astigmatic correction, focal characteristics or method of application. The most common types are:
- Monofocal Intraocular Lenses (Single-Focus Lenses)
The oldest and most widely used intraocular lenses, monofocal intraocular lenses are single-focus lenses. They provide distance vision either without glasses or with low-prescription glasses. However, because they have no near focus, the patient continues to wear glasses for near and intermediate vision.
Monofocal intraocular lenses are preferred for patients with glaucoma, age-related macular degeneration or retinal problems.
They are the most cost-effective lenses. Depending on quality, they may incorporate UV and blue-light filters. Distance-vision quality is high, and they do not cause night-time light scatter.
- Toric Intraocular Lenses
Toric lenses are intraocular lenses used in cases of astigmatism. Astigmatism is a refractive error caused by the cornea or the intraocular lens losing its ideal shape; it manifests as difficulty seeing at night, blurred vision and headaches. Intraocular lenses placed in the eye to correct this defect and naturally restore both near and distance vision are called toric intraocular lenses. The procedure first requires removal of the natural intraocular lens.
- Multifocal Intraocular Lenses (Multi-Focus Lenses)
Since monofocal intraocular lenses do not free the patient entirely from glasses, multifocal intraocular lenses have been developed to address this issue, with at least two foci or a single multifunctional focus. These lenses incorporate rings that focus images from various distances onto the retina. Although patients may struggle at first, over time they see near, intermediate and distance vision very clearly.
- One of the most common types of multifocal intraocular lens is the “Trifocal Intraocular Lens”. As the name suggests, these premium lenses have three foci: one for distance, one for computer distance, and one for reading distance. They produce very successful results for tasks where monofocal intraocular lenses fall short, such as reading mobile-phone screens and product labels. However, in the dark — under streetlights, car headlights, etc. — patients may experience halos and glare in the early period. This effect will diminish over time as the brain adapts.
The lens’s UV-protective property shields your eyes from the harmful effects of sunlight and helps prevent age-related changes in the eye.
- Another type of multifocal intraocular lens is the Accommodating Intraocular Lens, which is single-focus but multifunctional. After the cataractous natural lens has been removed, it works by harnessing the functions of the ciliary muscle.
- Extended Depth-of-Focus Intraocular Lenses (EDOF) have been developed to reduce night-time light scatter and the formation of haloes. Although their near-vision performance is lower compared with trifocal intraocular lenses, they yield better results at intermediate and distance ranges.
4. Phakic Intraocular Lenses
The state in which the natural lens of the eye is still present is called “phakic”. Phakic intraocular lenses are intraocular lenses applied without removing the natural lens.
Made of plastic or silicone, phakic intraocular lenses are permanently implanted in front of or behind the iris to reduce the patient’s need for glasses or contact lenses by addressing refractive errors. They cannot be used in the presence of cataract.
They may be applied in patients who are not suitable for LASIK (commonly known as having the eye etched) or whose prescriptions are very high. They differ from monofocal, toric and trifocal intraocular lenses in terms of where they are implanted.
5. Add-on Intraocular Lenses (Sulcoflex Secondary Lens)
These are artificial intraocular lenses placed to support near or distance vision in patients who have previously undergone cataract surgery, had their natural lens removed and an artificial intraocular lens implanted.
You may also wish to read our article on intraocular lenses, “Premium Smart Lens Applications”.
Possible Problems and Solutions After Intraocular Lens Surgery
- If residual refractive error remains, and provided it is medically appropriate, the refractive error can be zeroed by laser eye surgery.
- Although rare, conditions such as corneal oedema (oedema of the transparent layer of the eye), corneal damage, raised intraocular pressure and eye infection may occur after surgery. All of these resolve with the drops prescribed by the doctor.
- If the natural lens is touched during surgery, a cataract may develop in the natural intraocular lens. Although undesirable, the problem will be resolved with a second surgery directed at the cataract.
Prepared by the Editorial Board of the Eye Foundation Hospitals.
