Bedisha Biswas, Diploma in Optometry
Bachelor of Clinical Optometry student, Pailan College of Management and Technology, Kolkata, India
Presbyopia is a natural ageing of the eye where one gradually loses the ability to focus near objects. Usually, it becomes noticeable in the early to mid-40s as the lens becomes more rigid and cannot change its shape easily and it continues to worsen until around age 65. (1)
Many people seek laser eye surgery for presbyopic correction. Modern evolutions in corrective eye surgery have enhanced the number of available modalities for presbyopia correction. Presently, a new Intra-Corneal laser procedure called IntraCOR (inside-the-cornea) may soon become a conventional presbyopic correction surgery. Though the FDA has not yet approved IntraCOR for use in the US, but this has shown optimistic results in early studies performed in South America and Europe.(2)
What is InraCOR?
The IntraCOR procedure is a femtosecond laser-based incisional method for intrastromal correction of presbyopia using the Technolas 520FS femtosecond laser platform.(3) Two to five cylindrical ring incisions are created in the corneal stroma (centre of the visual axis) aiming to change its biomechanical properties and induce a central hyperoprolate region for the treatment of presbyopia.(3)
In October 2007, Colombian eye surgeon Luis Ruiz (MD), first performed the IntraCOR procedure for the presbyopic correction.(4) Dr. Ruiz and colleagues conducted a study of 83 eyes of 45 presbyopic patients and his studies have shown improved uncorrected near visual acuity with minimal or no change in uncorrected distance visual acuity.
For the presbyopic correction, IntraCOR is like Presby-LASIK in many respects. Yet IntraCOR has more advantages of being less invasive and no need for corneal flap.
The IntraCOR procedure is performed based on an individual patient and requires local anesthesia. A mild oral sedative to relax one before surgery (if needed) and can be performed within few minutes.(5)
Image-3: IntraCOR Procedure (2)
Depending on the patient’s need and eye health, IntraCOR can be performed on both eyes and just one eye.
How IntraCOR improves your reading?
IntraCOR is a reassuring treatment option for presbyopic patients with hyperopia and lower amounts of myopia. During this procedure, an intrastromal ablation pattern is created without any need to cut the corneal surface. This minimizes potential risks of infection.
Image-4: Mechanism of IntraCOR (2)
- The most common limitation following the procedure is seeing halos around light. It is disturbing especially at night and some reported hardship in night-driving. These halos diminished with time over a year.
- For the presence of gas bubbles from ablation of femtosecond laser in the stroma, the patient’s vision is blurry for several hours. After 2-3 hours, the bubbles dissolve, and vision becomes clear.(6)
- This procedure is mainly designed for presbyopic patients associated with hypermetropia and not very much appealing for presbyopic patients with myopia as this can cause a myopic shift of -0.50D.(3,7)
- As IntraCOR is not easy to reverse, patient selection for this procedure is very important.(8)
Presbyopic correction remains a great challenge in refractive surgery. Lens-based technologies developed dramatically over the last decade. In the next few years, we will be witnessing many new technologies which will provide our patients with great vision at every distance. The femtosecond laser is one of them. This technology is hastily developing and serving a heavily utilized method in corneal refractive surgical procedures due to its reproducibility, safety, precision, and veracity.(7)
- Presbyopia: Overview: Mayo Clinic- https://mayocl.in/3yqSan9
- IntraCor – An Inside-the-Cornea Laser Treatment for Presbyopia- Refractive Surgery News- https://bit.ly/3sU6qUz
- Ruiz LA, Cepeda LM, Fuentes VC. Intrastromal correction of presbyopia using a femtosecond laser system. J Refract Surg. 2009;25(10):847-854.
- Intrastromal Femtosecond Laser Presbyopia Correction: 1-year Results of a Multicenter Study- Mike P. Holzer, MD; Michael C. Knorz, MD; Mark Tomalla, MD; Tobias M. Neuhann, MD; Gerd U. Auffarth, MD- December 28, 2011.
- Presbyopia Treatment- Orry Birdsong, M.D. on October 17, 2019- https://bit.ly/3sU69B1
- Update on InraCOR: Mike P. Holzer, MD; 2009- https://bit.ly/3ztlv1z
- Holzer MP, Mannsfeld A, Ehmer A, Auffarth GU. Early outcomes of INTRACOR femtosecond laser treatment for presbyopia. J Refract Surg. 2009;25(10):855-861.
- Femtosecond Laser Technology in Corneal Refractive Surgery: A Review-George D. Kymionis, MD, PhD; Vardhaman P. Kankariya, MD; Argyro D. Plaka, MD; Dan Z. Reinstein, MD, MA(Cantab), FRCSC, FRCOphth, FEBO- October 18, 2012.
- Chung SH, Mazur E. Surgical applications of femtosecond laser. J Biophotonics. 2009;2(10):557-572.
- Image 1: Edited by the author- https://bit.ly/3jqrmPH & https://bit.ly/3sWA9fw /; Image 2: https://bit.ly/3Bpr5CG
- Image 3 & 4: Digitally modified and created for representational purpose by the author
- The blog is written solely for education purpose, and it does not have any financial support and conflict of interest.