In what ophthalmic surgeries are they used?

An IOL, also known as an intraocular lens, is a synthetic, artificial lens implanted inside the eye to replace the focusing power of the eye’s natural lens.

IOLs are most commonly used in cataract surgery to regain clear vision once the cataract is removed. IOL’s are also used  to correct a variety of refractive errors, including myopia (short-sightedness), hyperopia (long-sightedness), astigmatism, and presbyopia (age-related loss of near vision) in those patients who are over 50 and are not affected by cataracts. This procedure is  called refractive lens exchange or RLE.

What is an IOL made of?

As pictured, IOLs are small, clear lenses, usually made from specialised plastics such as acrylic, collamer, or silicone. Most modern IOLs are flexible and foldable, allowing them to be inserted through a small incision in the eye. The lens is held in place by plastic side struts called haptics, which anchor the IOL inside the eye.

Types of IOLs

There are several types of intraocular lenses, each designed for specific visual needs which are explained briefly below. An ophthalmologist will examine each unique eye, as well as aim to understand the visual goals of their patient, before making a recommendation as to which IOL is most suitable.

• Monofocal IOLs provide clear vision at one distance, most commonly set for distance vision. Patients may still require glasses for near or intermediate tasks.
• Multifocal IOLs offer multiple focal points, allowing for improved vision at various distances (far, intermediate, and near), reducing the need for glasses.
• Toric IOLs are designed to correct astigmatism by compensating for the irregular curvature of the cornea or lens. Toric lenses are available in monofocal and multifocal lens ranges.
• Extended Depth of Focus (EDOF) IOLs provide a continuous range of vision from distance to intermediate but may still require glasses for near tasks.
• Phakic IOLs are implanted without removing the natural lens, these IOL’s are used for refractive correction in patients with high myopia and sometimes hyperopia, typically in younger individuals.

What ophthalmic surgery uses IOLs?

 Cataract surgery is the most common procedure involving IOL implantation. A cataract is a clouding of the eye’s natural lens, leading to blurry vision, glare, and reduced colour perception and has a number of causes which are outlined here. During surgery, the cloudy natural lens is removed and replaced with an IOL, restoring clear vision and often correcting pre-existing refractive errors.

Refractive Lens Exchange (RLE), also known as clear lens extraction , is performed to correct refractive errors in patients who do not have cataracts but wish to reduce or eliminate dependence on glasses or contact lenses and is an alternative to laser vision correction. This procedure is nearly identical to cataract surgery, but the lens being replaced is clear rather than cloudy, and it is generally recommended for individuals over 50, as lens changes due to aging (otherwise known as presbyopia) are a primary cause of refractive error in this population.

Phakic Intraocular Lens Implantation is used for refractive correction in patients with high degrees of myopia (near-sightedness) and sometimes hyperopia (far-sightedness) who are not suitable candidates for laser vision correction. The natural lens remains in place, and the IOL is implanted behind the iris and infront of the natural lens. This approach is reversible and is typically indicated for patients usually under 45 years of age.

A simple overview of the IOL surgical procedure

With high success rates, fast recovery time depending on the surgical procedure and its complexity, IOLs, and the advancement of this technology have revolutionised the way in which ophthalmologists’ can aid visual acuity.  A simple description of how they are used is below.

• Preparation: The eye is numbed with topical or local anaesthesia.
• Incision: A small incision is made in the cornea.
• Lens Removal: In cataract surgery or RLE, the natural lens is broken up and removed.
• IOL Insertion: The folded IOL is inserted through the incision and positioned in the capsular bag or other appropriate location.
• Phakic IOLs: These lenses are placed in front of the natural lens but behind the iris (posterior chamber type)
• Recovery: The procedure is typically completed within 30 minutes, and patients can usually resume normal activities within a few days, although strenuous activity should be avoided for about a week.

The advantages and risks of IOLs

As with any surgery, the implantation of IOLs does come with some risks, but they are low and although not preferable can often be remedied with further surgery.

 Advantages:

• Restoration of clear vision after cataract removal.
• Correction of refractive errors to remove the need for visual aids like glasses or contact lenses.
• Quick recovery and minimal discomfort for most patients.
• Relatively non-invasive surgery that is performed as a day procedure.
• Extensive choice of which IOL to use so able to be tailored to the individual.

Risks:

• Infection, bleeding, inflammation, or retinal detachment are rare but possible complications.
• Glare or halos, especially with multifocal IOLs, are experienced by some patients as the brain adapts to the new lenses but this most often resolves within 6-12 months. In a very small number of cases there may be the need for additional surgery.

Conclusion

IOLs (intraocular lenses) are a versatile and effective ophthalmic solution for restoring vision in patients with cataracts or refractive errors. They are used in a variety of ophthalmic surgeries, most notably cataract surgery and refractive lens exchange to correct high myopia, hyperopia, astigmatism, and presbyopia.

This technology and therefore the options available for patients continues to evolve and modern IOLs are made from advanced materials and come in several types to address different visual needs, offering improved quality of vision and reduced dependence on glasses or contact lenses.

The choice of IOL and surgical approach depends on the patient’s unique eye health and shape, the reason for undertaking the procedure, patient age and visual goals, and is made in consultation with a specialist ophthalmologist.

Would you like to be referred to our care?

Adelaide Eye & Laser Centre is one of Adelaide’s premier ophthalmic consulting clinics, was the first in South Australia to offer Laser Vision Correction, and is one if its most experienced in cataract and other refractive procedures.

If you would like a referral to the care of one of our ophthalmic specialists, or have any questions, please do not hesitate to contact a member of our friendly team on 08 8274 7000 or by filling out the contact form here.