LENS INNOVATIONS IN CATARACT TREATMENT
The evolution of cataract surgery has been marked by significant developments in techniques and lens technology. These improvements have not only enhanced the outcomes and safety of the procedure but have also provided patients with more satisfying results.
As Singapore contends with a notable increase in cataract prevalence among our ageing population, the need for enhanced treatment options has never been more crucial. The integration of new materials and ongoing research continue to reshape patient expectations and set new benchmarks in eye care. This blog delves into recent developments in lens technology and other industry-recognised innovations in cataract treatment worldwide.
Importantly, modern cataract surgery now offers patients a remarkable possibility: the opportunity to live glasses-free. This ultimately represents a transformative shift from merely providing an alternative to wearing glasses to potentially eliminating the need for them altogether.
Widely Available Vision Correction Options
Vision correction technology has evolved significantly, offering patients various options to address their unique needs. Here are the most widely available options, particularly for those undergoing cataract surgery or seeking alternatives to eyeglasses.
- Distance Only Vision Correction
Monofocal lenses are designed to correct vision at one specific distance, typically for seeing far objects clearly. This type of lens is ideal for patients who do not mind wearing glasses for closer activities but wish to have excellent distance vision without dependence on spectacles.
- Distance and Intermediate Vision Correction
Extended depth of focus (EDOF) lenses provide a more seamless visual experience from distance to intermediate without the traditional limitations of bifocals. Lenses like these extend the range of vision with a single focal point that is spread over a range, reducing the need for glasses for activities like using a computer or driving, which require good intermediate vision.
- Distance, Intermediate, and Near Vision Correction
Multifocal lenses are designed to correct vision at multiple distances by having different zones for near, intermediate, and far vision. Patients can read a book, work on a computer, and drive, all without the need to switch between different glasses.
Similar to multifocal lenses, trifocals provide clear vision at three different distances. They have specific zones dedicated to near, intermediate, and far vision. These are particularly beneficial for patients who need clear vision across all distances and wish to be independent from glasses as much as possible.
Innovations in lens technology continue to push the boundaries of what’s possible in eye care, allowing patients to be free of eyeglasses post surgery, so they may see the world more clearly and live with greater freedom and comfort.
Extended Depth of Focus (EDOF) IOLs
Extended depth of focus (EDOF) intraocular lenses are a more recent development in cataract surgery and the treatment of presbyopia. EDOF IOLs are particularly useful for patients who prefer to see clearly at close and mid-range distances without the need for spectacles.
These lenses aim to enhance the depth of focus and reduce photic phenomena which are common issues with multifocal IOLs. Photic phenomena encompass visual effects triggered by light, including optical effects like halos and rainbows.
EDOF lenses can be categorised into five groups based on their optical designs:
- Spherical Aberration (SA) Based EDOF. These lenses manipulate SA to increase depth of focus. They are pure EDOF lenses and provide a continuous range of focus without secondary out-of-focus images. Spherical aberration is a type of optical error that occurs when light rays passing through a spherical surface (like a lens or mirror) are refracted at different angles, causing them to converge at different points—resulting in a blurred or distorted image.
- Small Aperture Lenses. These lenses use the pinhole effect to extend the range of visual acuity. They are also pure EDOF lenses.
- Multifocal (MF) Lenses. These have a low addition for near vision, referring to a small amount of extra lens power added to a person’s distance prescription to help with close-up vision.
- Hybrid EDOF-MF Lenses. These lenses combine manipulation of SA with modest power addition for near vision. They are not pure EDOF lenses.
- Modulation of Wavefront. These lenses use a variation in the geometry of the central zone in the optic to cause an increase in depth of focus. In simpler terms, it involves controlling the phase distribution of light waves to create a specific pattern that enhances the depth of focus. They are not pure EDOF lenses.
While EDOF IOLs can increase the range of vision, they may reduce the clarity of images, especially for close-up viewing. This happens because adjusting the lenses to see further can decrease the quality of the retinal image.
Aspheric Intraocular Lens
Aspheric IOLs technology in the field of ophthalmology have been introduced since the early 2000s. These lenses are designed to have a front surface that is not curved as part of a perfect sphere, but is instead flatter in the periphery. This aspheric design aims to neutralise the positive spherical aberration of the cornea, which can impair optical quality and visual performance.
The key benefits of aspheric IOLs include improved optical quality, leading to better visual acuity, contrast sensitivity, and eyesight in low-light conditions. Some aspheric IOLs can be customised based on the individual patient’s corneal spherical aberration, allowing for more personalised correction. Additionally, they result in reduced photic phenomena.
However, there are also some limitations and considerations with aspheric IOLs. These are generally more expensive than traditional spherical IOLs. Additionally, they require specialised training and experience for surgeons to effectively use. Likewise, aspheric IOLs are not readily available in some parts of the world as yet.
The long-term visual outcomes are still dependent on the individual patient’s retinal health and other factors. Careful patient selection and management of expectations is important when considering aspheric IOLs.
Light Adjustable Intraocular Lens (LALs)
The light adjustable lens (LALs) is the only artificial intraocular lens that allows doctors to design, test, and tailor a patient’s vision post-cataract surgery. Made from a unique photosensitive material, this lens’s power can be adjusted using ultraviolet (UV) light to enhance the success of the procedure.
LALs have been shown to improve uncorrected distance vision to 20/20 in many patients, potentially achieving clearer vision without glasses. Moreover, LALs are designed to provide a wide depth of focus, which can improve intermediate and near vision without compromising distance vision.
The adjustable nature of LALs can help reduce photophobia, which is a common issue with traditional IOLs. People with photophobia may find sunlight or artificial light, like fluorescent or incandescent light, uncomfortable or painfully bright. This sensitivity can cause them to squint or feel the need to close their eyes when exposed to light.
Despite its benefits, the adjustment process for LALs is not without limitations. There are restrictions on the amount of correction that can be made in a single treatment, and the process may require multiple adjustments to achieve optimal results. Moreover, there is a risk of overcorrection when adjusting LALs, which can lead to reduced visual acuity. As LALs are a relatively new technology and may not be widely available for all patients.
The Evolution of Cataract Surgery Technology
Optiwave Refractive Analysis (ORA)
Optiwave refractive analysis (ORA) technology in cataract surgery introduced in the early 2000s, measures the eye’s refractive power in real-time. This helps surgeons optimise visual outcomes by selecting and positioning the IOLs more accurately. ORA is especially useful for patients with previous eye surgeries like LASIK, or those with significant vision issues like severe nearsightedness, farsightedness, or astigmatism.
ORA provides continuous measurements of the eye during surgery, enabling the surgeon to make adjustments in real-time to ensure optimal outcomes. Additionally, it helps the surgeon select the appropriate IOL based on the patient’s specific needs, including lens power, astigmatism, and aphakic and pseudophakic measurements. By ensuring proper IOL placement and adjusting for astigmatism, ORA can significantly reduce the need for additional procedures.
However, ORA may not be widely available for all patients. Moreover, surgeons require extensive training and experience to effectively use ORA technology, which can be a challenge for some practices. Access to this technology may be limited as it is not yet widely available in all regions.
Femtosecond Laser-Assisted Cataract Surgery (FLACS)
Introduced in 2009, the femtosecond laser-assisted cataract surgery (FLACS) utilises a femtosecond laser to perform critical steps of the procedure. It affords greater precision and consistency in making cuts during surgery compared to manual methods, resulting in stronger and more accurate capsulorhexis. A capsulorhexis is a surgical procedure used during cataract surgery that involves removing part of the lens capsule.
FLACS also allows for better management of astigmatism and lens placement, using less energy during surgery. Despite its technical benefits, it is more expensive and has not been shown to be more cost-effective compared to traditional methods.
Research continues to assess whether FLACS is safer or more beneficial than conventional surgery, as many of these lasers have only recently received FDA approval. More evidence is needed to fully understand its long-term impact and cost-effectiveness.
Meet our Medical Director: Dr Lim Wei Kheong Jimmy
MBBS, MMed (Ophth), MRCSEd (Ophth), FRCSEd (Ophth), FAMS
Types of Cataract Surgery
Over the past two decades, three types of cataract surgery have emerged as today’s standards:
phacoemulsification (PHACO), extracapsular surgery (ECCE), and laser-assisted cataract surgery (LACS).
The “traditional” PHACO method uses an ultrasound probe to break up and remove the cloudy lens through a small, self-sealing incision in the cornea. It offers a quick recovery and minimal discomfort, but may not be suitable for very dense cataracts.
Meanwhile, the ECCE, typically used for dense or hard cataracts, involves removing the lens in one piece through a larger incision, requiring stitches and a longer recovery. It remains a good option for advanced cataracts.
The LACS procedure, on the other hand, utilises a laser to make incisions and soften the cataract, but is more costly than traditional methods.
Traditional cataract surgery involved the implantation of monofocal lenses, which provided clear vision at one distance but often required glasses for intermediate and near vision tasks. However, recent innovations in monofocal intraocular lens (IOL) design and material have improved the clarity and reduced visual disturbances. Meanwhile, toric lenses, which correct astigmatism, have also become more prevalent, offering patients more vision options and enhancing the overall quality of their vision.
Looking for Cataract Surgery in Singapore?
Before anything else, consult with an experienced eye surgeon who can provide professional medical guidance tailored to your unique needs. It is also advisable to familiarise yourself with the entire surgical process, from pre-operative preparation through to post-operative care, to fully understand what to expect at each stage. Your surgeon will explain the potential risks and benefits of the procedure and will be available to address any questions or concerns you may have.
At JL Eye Specialists, we are recognised for our skills in cataract surgery and a broad range of ophthalmic services. We offer a holistic approach to care, ensuring that each patient receives personalised attention throughout their treatment.
Our Medical Director, Dr. Jimmy Lim, is a seasoned ophthalmologist with extensive experience in managing cataracts, performing refractive surgery (LASIK), and treating corneal conditions. With previous senior consultancy roles at the National Healthcare Group Eye Institute and advanced fellowships in both the United States and Switzerland, Dr. Lim brings over 20 years of experience and a deep reservoir of knowledge to our clinic.
If you have any concerns regarding cataract surgery, we invite you to schedule a consultation or contact us at 6258-8966 if you need more details.
SOURCES:
- National Center for Biotechnology Information. (2023). Enhanced Depth of Focus Intraocular Lenses: Through Focus Evaluation of Wavefront-Shaping versus Diffractive Optics. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10015109/
- National Center for Biotechnology Information. (2011). Multifocal versus monofocal intraocular lenses in cataract surgery: A systematic review. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3249813/
- ResearchGate. (2022). Optiwave Refractive Analysis (ORA). Retrieved from https://www.researchgate.net/publication/363346418_Optiwave_Refractive_Analysis_ORA
- Review of Ophthalmology. (2205). Aspheric IOLs: from Theory to Practice. Retrieved from https://www.reviewofophthalmology.com/article/aspheric-iols-from-theory-to-practice
- Frontiers in Medicine. (2023). Femtosecond laser-assisted cataract surgery: Update and perspectives. Retrieved from https://www.frontiersin.org/articles/10.3389/fmed.2023.1131314/full
- Mayo Clinic. (n.d.). Fine-Tuning Cataract Surgery: Light Adjustable Lens. Retrieved from https://www.mayoclinic.org/medical-professionals/ophthalmology/news/fine-tuning-cataract-surgery-light-adjustable-lens/mac-20547102
- Ministry of Health, Singapore. (n.d.). Operational Policy on Cataract. Retrieved from https://www.moh.gov.sg/docs/librariesprovider5/resources-statistics/information-papers/op_on_cataract.pdf
- National University Hospital. (n.d.). Cataract. Retrieved from https://www.nuh.com.sg/Health-Information/Diseases-Conditions/Pages/Cataract.aspx
- American Academy of Ophthalmology. (n.d.). Cataracts: IOL Implants. Retrieved from https://www.aao.org/eye-health/diseases/cataracts-iol-implants
- Hospital News. (n.d.). The Evolution of Cataract Surgery and Innovation in Today’s Lens Options. Retrieved from https://hospitalnews.com/the-evolution-of-cataract-surgery-and-innovation-in-todays-lens-options/
