Refractive Procedures

Refractive surgery

Refractive eye surgery is any eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea or cataract surgery. There are many refractive eye procedures that can reduce or cure common vision disorders such as myopia, hyperopia and astigmatism.

The procedures offered at our institute

  • Laser assisted in situ Keratomileusis(LASIK)
  • Phakic IOL’s
  • Limbal relaxing incisions
  • Refractive lens exchange
  • Refractive IOL Exchange

Limbal Relaxing Incisions (LRI)

What are LRI’s?

Limbal Relaxing Incisions (a subset of astigmatic keratotomy) are partial thickness incisions made at the corneal periphery for the treatment of corneal astigmatism.

What is Corneal Astigmatism?

Abnormal curvature of the cornea with at least two axes of steeper and flatter curvature, which can result in abnormal focussing of light and impaired vision. Astigmatism typically results from curvature abnormalities of the front (anterior) surface of the cornea

Who are the suitable candidates?

Limbal Relaxing Incisions are for those:

  • who have astigmatism
  • want to reduce or eliminate their dependence on glasses or contacts
  • have no health issues affecting their eyes

The pros of LRIs include

  • Easier to perform, less dependent on thickness of cornea, less likely to result in over corrections, quicker post-op stabilization of refraction, postoperative topography is smoother/more homogenousm (coupling).
  • LRIs are best for low to moderate amounts of astigmatism (< 3 diopters).

The cons of LRIs include

  • A larger incision (typically one or two incisions 1-3 clock hours in arc length)

Relative Contraindications for LRIs

  • Keratoconus
  • Any corneal disease/disorder
  • Prior corneal surgery, particularly incisional procedures

Possible Side effects/ Complications

  • Infection
  • Overcorrection- Wait for the refraction to stabilize.
  • Undercorrections- may be corrected by enlarging the original incision.
  • Corneal perforation-Incisions should be examined carefully at time of placement for corneal perforation. If a perforation is noted, it should be sutured if it is not self-sealing. This will limit the effect of the procedure.
  • Induced astigmatism, discomfort and decreased corneal sensation are other less common side effects

Realistic expectations

The decision to have LRIs is an important one that only you can make. The goal of any refractive surgical procedure is to reduce your dependence on corrective lenses. However, we cannot guarantee you will have the results you desire.
Serious complications to LRIs are extremely rare. If you decide that LRIs are an option for you, you will be given additional information about the procedure that will allow you to make an informed decision about whether to proceed. Be sure you have all your questions answered to your satisfaction.

Phakic Intraocular lenses

What are Phakic IOL’s?

Intraocular lenses have been used since 1999 for correcting larger errors in myopic (near-sighted), hyperopic (far-sighted), and astigmatic eyes. Phakic intraocular lens (PIOL) implant can be employed to correct either extreme farsightedness or extreme nearsightedness. Unlike cataract surgery, your natural lens is not removed -- instead, the implant is secured in front of the natural lens, essentially making the PIOL implant an internal contact lens.

The difference between them and those that implanted during cataract eye surgery is that they are implanted in the presence of the natural crystalline lens in order to correct refractive errors while in cataract surgery, the natural lens which became opacified will be removed and replaced by artificial intraocular lens.
Implantable contact lens technology has arisen out of the rapid advances in today's cataract surgery. Utilizing cutting edge equipment, ophthalmologists can insert flexible intraocular lenses (used to replace the natural lens after cataract surgery) through extremely small incisions.

What is Phakic IOL made off?

It is made from a 100% pure collagen copolymer material that is biocompatible with your body’s natural chemistry. Once implanted, you will not feel the implant and it cannot be detected cosmetically.The material’s characteristics are very similar to the natural crystalline lens allowing it to transmit light much like the natural lens.

Criteria for Phakic IOL

In order to decrease post operation complications, patients should be good candidates and should be selected for phakic intraocular lens implant according to certain criteria.

  • Stable refractive error in the last 6 months with less than 0.5 D change.
  • The natural crystalline lens should be clear.
  • Patient have high refractive errors.
  • Patient is not happy with his vision with spectacles or contact lenses.
  • Patient is not a good candidate for excimer laser surgery.
  • Patient has no ocular diseases or pathology.
  • Has deep anterior chamber which should be greater than 3.0 mm.

The upper limits of lasik and PRK for correction of myopic patient are -12D to -14D, +4D to +6D for hyperopia and 4-5D for astigmatism because behind those limits, the risk of complications of them will increase.
Phakic IOL can correct high myopia of around -20D to – 30D, hyperopia up to +3.0D.
Till now, only spherical correction by Phakic IOL is approved by FDA but astigmatism can be corrected by using toric Phakic IOL.

Course of the procedure

Phakic lenses are implanted into the eye in addition to the eye’s natural lens. A small incision (approximately 3 – 5 mm) is placed at the periphery of the cornea. Some lenses are flexible and therefore foldable, which reduces the incision needed to 3.2 mm.

Types of Phakic IOL

Depending on the type of phakic lens, two positions within the eye are possible: Some lenses such as the Acrysof, Artiflex or Verisyse phakic lenses are placed into the anterior eye chamber and secured into place on the iris. Other lenses, such as the ICL collamer lenses , are placed into the posterior eye chamber behind the iris and in front of the natural lens.

Who is a candidate for a phakic lens implant?

Phakic lenses are mainly used for correction of moderate to severe nearsightedness and farsightedness. Younger patients, who do not yet need reading glasses, generally receive a synthetic lens implant while keeping their eye’s natural lens. For older patients, it is usually better to exchange the eye’s natural lens with a synthetic lens of the appropriate prescription.

For whom are phakic lenses not suitable?

Generally, patients with chronic and progressive disorders of the eye, such as glaucoma and certain retinal disorders as well as patients younger than 18 years old, should not receive a phakic lens implant.

Is an enhancement procedure possible?

Yes. Generally, the implant of a synthetic lens reduces the refractive error significantly. However, total freedom from wearing eyeglasses cannot be achieved in all cases. If a refractive error remains after a phakic lens implant, it can be corrected with an additional laser surgery, also known as LASIK.

Which problems can occur with synthetic lenses?

When the pupil is dilated at dawn and at dusk, the refraction of rays of light at the edge of the synthetic lens can lead to an increase in glare. Additionally, long-term results dating back numerous years are not yet available for some of the newer and more modern synthetic lenses. Finally, the procedure involves a surgery in the inner eye, meaning that in extremely rare cases severe side effects are possible.

What can you do to see well with phakic lenses?

  • Do not rub on your eyes for the first few days after surgery!
  • Apply the eye drops regularly as prescribed by your physician; only use the eye drops or the amount of time specified by your physician;
  • Keep appointments for your postoperative eye exams.
  • Schedule a checkup once a year so that possible long-term effects can be detected early.
  • Contact your physician immediately if you experience severe pain or a sudden decrease in vision.

Which problems may occur that are beyond my control?

  • Glare and halos at twilight and at night
  • Infection, an increase in internal pressure of the eye, opaqueness of the cornea
  • Secondary cataract

Refractive Lens Exchange

What is refractive lens exchange procedures?

RLE is essentially the same as cataract surgery, but by its very definition, includes the removal of a clear natural lens as opposed to a cataract. This procedure has more inherent risks than corneal refractive procedures because the lens of the eye is located behind the iris (behind the pupil as well) and thus, removal of the lens and replacement with an artificial implant becomes intraocular surgery.

What are the indications?

Refractive lens exchange (RLE) is a procedure that should be reserved specifically for individuals that are significantly presbyopic (reading glasses dependent). RLE is a potential option for presbyopic patients who have refractive error including hyperopia (farsightedness) of +1.0 diopter and greater and myopia (nearsightedness) of –1.0 to about –8.0 diopters who are at least 40 to 50 years of age, and in whom other less invasive procedures (such as LASIK, Epi-LASIK, IntraLASIK, phakic IOLs, and conductive keratoplasty) do not fully meet the individual's needs. If you are above the age of 55 or 60, you should strongly consider RLE due to increasing presbyopia.
If you have more than –8.0 or –9.0 diopters of myopia, RLE may not be your best option due to increased risk of retinal detachment in axially long eyes following RLE or cataract surgery. However, if you're about 60 years of age or higher, and cataract surgery is relatively imminent anyway, then RLE may still be your best option even if you're a high myope, that is, above –8.0 or –9.0 diopters.
This is only possible by implanting an "accommodating IOL" or a multifocal IOL. Now, to be sure, RLE does not require implantation of either of these types of lenses, but this is the only option that would generally allow distance and near vision simultaneously.

Potential Risks and Complications of RLE

Today, cataract surgery is one of the most successful procedures in all of medicine. Refractive lens exchange should enjoy the same or perhaps even greater success, given that the procedures are practically identical. However, complications will still occasionally occur and may range from devastating visual loss to minor inflammation in the eye.

Selecting An Intraocular Lens (IOL)

When the natural lens of the eye is removed, whether it is clear or a cataract, it is generally replaced with an IOL. There are a variety of IOLs that are available today, each of which has advantages and disadvantages. Like refractive surgery itself, we're beyond the era of "one size fits all", or in this case, one type (of lens) fits all. The type of IOL chosen must be tailored to each patient's individual needs and desires

Refractive IOL Exchange

What is IOL Exchange?

Today state-of-the-art technology, namely premium IOLs, are provided to the patients when performing cataract surgery inorder to meet patient expectations for overall quality of vision after surgery. However if a patient is dissatisfied with the IOL implant, then all options should be considered to rectify the problem, including refractive surgery to correct the residual refractive error or even IOL exchange. In some cases, refractive surgery may not be possible due to corneal parameters, and the only option may be IOL exchange. There are many IOL exchange techniques that can be safely executed in such circumstances to convert an unhappy patient to a fully satisfied patient.
Adopting this approach can easily solve postoperative surprises and help dissatisfied patients by simply addressing the problem, whether it is a biometry surprise or just a patient that cannot tolerate some of the visual symptoms associated with multifocal IOLs.