Cataracts are the leading cause of blindness worldwide, affecting nearly 65 million people.1 Cataracts form when proteins in the lens are damaged and clump together, reducing the amount of light that is passed from the lens to the retina and thereby causing loss of sight. The primary risk factors for cataract development are age, steroid use, family history, and trauma.2 To date, the most effective course of treatment for cataracts is phacoemulsification, a surgical technique involving the removal of the opaque lens and replacing it with an artificial intraocular lens (IOL). Continuing research and technological development have broadened the scope of available surgical techniques and introduced pharmaceutical agents that may be able to alleviate cataract symptoms and provide a new treatment approach.
Today, cataract surgery is one of the safest and most successful operations performed around the world. The demand for smaller, smoother, and more personalized IOLs has led to the development of new techniques in surgical cataract treatment, such as multi-focal IOLs, extended depth-of-focus IOLs, and toric IOLs. As a result of innovations in refractive optics, lenses with two or three focal points are available to patients undergoing cataract surgery.3 In contrast to the traditional mono-focal IOL implant, multi-focal IOLs can provide patients with greater visual acuity at both near and far distances.1 However, some patients may experience other optical phenomena after multi-focal IOL surgery, such as halos or glare. To address this, artificial lenses with an extended depth-of-focus (EDOF) have been developed. These lenses do not have predefined focal points; rather, the focus covers a wide range. EDOF IOLs can provide better visual acuity at intermediate distances, higher contrast sensitivity, and less glare than multi-focal lenses. Another option is toric IOLs, which may be used to help patients overcome corneal astigmatism. A toric lens can be integrated into a mono-focal, multi-focal, or EDOF lens; its aspherical shape creates different refractive outcomes on horizontal and vertical orientations.
Femtosecond lasertechnology, first developed in the 1990s, has promising applications for cataract treatment. Femtosecond laser-assisted cataract surgery (FLACS) is especially useful in lens fragmentation, anterior capsulotomy, and self-sealing corneal incisions. The laser enables precise implementation of each step of surgery, optimizing the refractive state of the eye and the implanted IOL. A randomized clinical trial with 130 patients found that patients with grade 2 cataracts receiving FLACS suffered less endothelial cell loss than their counterparts receiving phacoemulsification, indicating less tissue damage. In contrast with conventional phacoemulsification, low-energy FLACS was shown to preserve the hexagonal shape of corneal
endothelial cells in spite of high-grade cataracts.4 Despite the benefits of FLACS, including controlling complications and visual outcomes, its higher cost has so far prevented the widespread adoption of the technique.1
Although surgical options are preferred in severe cataract patients, patients with low-grade cataracts may consider pharmaceutical alternatives that may reverse cataract formation. A seminal study used whole-exome sequencing to identify two homozygous lanosterol synthase (LSS) missense mutations in families with extensive congenital cataracts. Computational models demonstrated engineered expression of LSS prevents intracellular protein aggregation of cataract-causing crystallins. Following these in silico assessments, the researchers performed subsequent experiments on dissected rabbit cataractous lenses and live dogs to show lanosterol treatment could reduce cataract severity and increase transparency.5 Future clinical trials will show whether this pharmaceutical approach will become a new treatment method for cataract patients.
Recent advancements in cataract surgery and treatment have significantly improved patient outcomes and quality of life. Multi-focal, EDOF, and toric IOLs provide greater versatility in vision correction, directing the aim of treatment toward vision improvement rather than vision rehabilitation. FLACS and pharmaceutical agents hold exciting potential, offering a future where patients may benefit from the convergence of surgical interventions and drug therapies. As more research is conducted and these technologies continue to evolve, cataract treatment will become safer, more accessible, and more tailored to the needs of the individual.
References
1. Chen, Xinyi, et al. “Cataract: Advances in Surgery and Whether Surgery Remains the Only Treatment in Future.” Advances in Ophthalmology Practice and Research, vol. 1, no. 1, Nov. 2021, p. 100008. https://doi.org/10.1016/j.aopr.2021.100008 2. Eye Health Data and Statistics | National Eye Institute. https://www.nei.nih.gov/learn-about-eye-health/eye-health-data-and-statistics
3. Lapp, Thabo, et al. “Cataract Surgery—Indications, Techniques, and Intraocular Lens Selection.” Deutsches Ärzteblatt International, vol. 120, no. 21–22, May 2023, p. 377. https://doi.org/10.3238/arztebl.m2023.0028
4. Schroeter, Anna, et al. “Comparison of Femtosecond Laser-Assisted and Ultrasound-Assisted Cataract Surgery with Focus on Endothelial Analysis.” Sensors, vol. 21, no. 3, Jan. 2021, p. 996. https://doi.org/10.3390/s21030996
5. Zhao, Ling, et al. “Lanosterol Reverses Protein Aggregation in Cataracts.” Nature, vol. 523, no. 7562, July 2015, pp. 607–11. https://doi.org/10.1038/nature14650
Recent Comments