Posted on January 7, 2018
What is farsightedness?
Farsightedness, or hyperopia is a condition of the eye in which parallel light rays entering the eye are focused behind the retina, resulting in blurred vision. In hyperopia, both near and distant objects appear blurry. This is because the length of the eyeball is shorter, and the focusing mechanism of the eye (cornea and lens) too weak to focus correctly. Hyperopia is traditionally corrected using convex or “plus” lenses, either in glasses or contact lenses.
Alternatively, vision correction surgeries or refractive surgeries may also be performed to minimize dependence on, and provide better vision without, glasses and contact lenses.
What are the options for better vision without glasses?
The surgical options depend one of the two mechanisms to provide vision correction. One, they increase the focusing power of the cornea by changing the shape of the cornea (the clear, dome shaped, out part of the eye) using a laser; or two, by placing an artificial lens inside the eye. LASIK and associated laser vision correction surgeries rely on the former mechanism, while the latter consists of phakic intraocular lens or refractive lens exchange. This article will focus on phakic IOLs or Implantable Collamer Lenses, ICL, for the correction of farsightedness.
What are ICLs?
Implantable contact lenses, also known as phakic IOLs, correct vision similar in function to contact lenses but do not require any handling on part of the patient. Phakic IOLs offer a form of permanent vision correction, invisible to the naked eye, since they are surgically placed inside the eye, between the iris and the natural lens of the eye. This is the anatomical position where intraocular lenses (IOLs), which are placed during cataract surgery, except IOL placement requires the removal of the natural lens of the eye, while ICLs sit on top of the natural crystalline lens of the eye. Alternatively, they may be placed on top of the iris, which is the brown/ blue/ black part of the eye.
Who needs an ICL?
ICL can correct myopia or near sightedness, farsightedness and astigmatism. In case of farsightedness, the ICL is ideal for patients greater than 18 years of age, with moderate to severe farsightedness, especially in patients not eligible for LASIK. ICL’s can be used to correct hypermetropia from +1.5D to around +18D. The newly introduced Toric ICL can also correct any associated astigmatism also. There are currently only two FDA-approved implantable contact lenses on the market, each of which has specific advantages and disadvantages. The best refractive surgery procedure will be decided by your eye surgeon after a comprehensive eye evaluation, and a detailed discussion with you about your needs and expectations.
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 ICL is a very thin, pliable lens which is folded before insertion through tiny incisions on the periphery of the cornea and placed behind, or in front of the iris, and in front of the natural lens. The lens unfolds into position, and no sutures or stitches are required during the surgery. The doctor uses local anesthetic drops to ensure that the surgery is painless, and you can go home two hours after surgery.
What are the advantages of ICL surgery?
The surgery is potentially reversible and provides very quick visual recovery and rehabilitation.
Also, the postoperative vision is described by patients as “perfect”, and much better than that after LASIK, because of optimal correction of spherical and astigmatic optical defects. In addition, it is free from side effects like dryness, glare and haloes. The ICL is made of a biocompatible polymer that blocks harmful Ultraviolet radiation protecting the eye from diseases which are associated with increased exposure to UV radiation, including cataract and Age Related Macular Degeneration.
What are the disadvantages of ICL?
The only real disadvantage of the ICL is its cost, which is significantly more than conventional LASIK, ICL implantation carries very small, but real risk of infection since it is an intraocular surgery. It also has an associated risk of damage to other structures in the eye, which can cause cataract, glaucoma, iritis, corneal decompensation, cystoid macular oedema, and retinal detachment. However, these complications are extremely rare and have been listed here to ensure proper follow up after surgery.
Overall verdict about ICL
Implantable Collamer Lenses provide an extremely safe and effective option for vision correction without glasses or contact lenses, even in patients who are not eligible for ALSIK. This has opened new vistas in vision correction for patients with farsightedness, with and without associated astigmatism, especially those who have been denied vision correction surgeries till now.