Posted on January 9, 2018
Nearsightedness, or myopia which is its technical name, is a refractive error in which the rays of light entering the eye are not focused on the light sensitive part of the eye, the retina. The light rays fall short of the retina, as they are focused too much: this can be because the curve of the cornea is too steep, or the eye ball is longer than it should be. This means that your vision for distance is blurred, while being perfect for near objects.
To correct this, you will be asked to use concave lenses, or lenses with a negative dioptric power to focus the light on to the retina again. These lenses can be either in your spectacles, or contact lenses.
For those patients who do not want to use either glasses or contact lenses, there are several surgical options available. The most popular refractive eye surgery, for removal of glasses, is of course, LASIK, but Implantable Collamer Lenses, or ICLs, have actually opened up a whole new world in refractive surgeries, even for those patients who were earlier considered ineligible for refractive surgeries. ICLs provide a safe and effective option not only for correcting nearsightedness, but also far sightedness and astigmatism.
What are ICLs?
Implantable collamer lenses, also known as phakic IOLs, correct vision like contact lenses, and offer a form of permanent vision correction. They are invisible to the naked eye, since they are surgically placed inside the eye, either between the iris and the natural lens of the eye, or on top of the iris. The former is used more commonly in India. The Visian ICL, manufactured by STAAR, Switzerland, is customized to the unique refractive error of the patient and can also correct astigmatism.
What are the indications for ICL in myopia?
The ICL, like all refractive surgeries, may be considered for patients greater than 18 years of age, with moderate to severe nearsightedness, especially in patients not eligible for LASIK. The Visian ICL is made of biocompatible polymer material and contains a UV absorber made from a UV absorbing material. ICLs can be used to correct myopia from + -3.0D to -15.0D with less than or equal to 2.5D of astigmatism at the spectacle plane, and the toric version can be used to correct any associated astigmatism up to 6D also.
The best procedure for you eye health and visual needs will be discussed with you in detail, by your eye surgeon after a comprehensive eye evaluation, and this article will only help you make an informed choice in association with your doctor.
Criteria for eligibility include:
- Age more than 18, preferably 21, and less than 45 years
- Stable prescription of glasses for at least six months to a year
- Not pregnant or breastfeeding
- Proper anterior chamber depth and healthy endothelium on eye evaluation by surgeon
- Patients not eligible for LASIK for example severe dry eye, high refractive error, thin corneas, stable keratoconus, status post corneal surgeries etc.
- Any associated ocular disease, including cataract, AMD, fuchs dystrophy etc.
- Immunosupression due to diseases like HIV, or due to use of prescription drugs that decrease immunity
- Any autoimmune or collagen vascular diseases like lupus, rheumatoid arthritis, scleroderma etc
- Iris deformities
What is the surgery like?
The Visian ICL is an extremely thin and flexible lens, so it can be folded and inserted in place, through an incision of 3.5mm or less. It is positioned directly behind the iris and in front of the anterior capsule of the human crystalline lens, and the incision is completely self-sealing. The surgery is extremely safe and effective in trained hands, done under topical anesthesia, and the visual recovery is also very rapid.
What are the advantages of ICL surgery?
The biggest advantage of ICL surgery is that it offers hope for better vision without glasses to those with high refractive errors hitherto not considered eligible for refractive surgeries like LASIK. It can also be done for patients with thin conreas, patients with stable keratoconus and patients who have had scarring from previous corneal surgeries, which opens a whole new dimension for the refractive surgeons armamentarium. In addition, the surgery is reversible, unlike LASIK, and provides very quick visual recovery and rehabilitation.
Also, the vision correction is better than that offered by glasses, contact lenses or even LASIK, due to optimal correction of spherical and astigmatic optical defects. In addition, the incidence of side effects like dryness, glare and haloes is much lower than that after LASIK. The ICL is made of a biocompatible polymer called collamer which blocks harmful UV radiation, providing additional protection against diseases like cataract and Age Related Macular Degeneration.
What are the disadvantages of ICL?
ICL surgery is considerably more expensive than conventional LASIK, which constitures its biggest disadvantage. In addition, since the surgery is an intraocular procedure (LASIK only touches the surface of the eye) it is associated with the possible risk of infection. It also may damage to other structures in the eye, which can cause cataract, glaucoma, iritis, corneal decompensation, cystoid macular oedema, and retinal detachment. It must be emphasized that these complications are extremely rare, and ICLs have proved to be extremely safe with pooled data available for more than one million surgeries under consideration.
Overall verdict about ICL
Implantable Collamer Lenses have proved to be an extremely safe and efficacious surgical option for patients with high refractive errors (myopia, hypermetropia and astigmatism), even in patients who are not eligible for LASIK. This means as on today, refractive surgeons can offer freedom from dependence on glasses to patients with high refractive errors and thin corneas alike.