Farsightedness, hyperopia, is a common vision impairment where distant objects are often seen clearly, but close-up objects appear blurry. LASIK, or Laser-Assisted In Situ Keratomileusis, is a widely performed refractive surgery that reshapes the cornea to correct such vision errors. This procedure aims to reduce or eliminate the need for glasses or contact lenses for those with farsightedness. This article explores how LASIK addresses farsightedness, candidacy, outcomes, and considerations.
Understanding Farsightedness
Farsightedness occurs when the eyeball is too short, or the cornea, the clear front surface of the eye, has too little curvature, causing light to focus behind the retina instead of directly on it. The retina is the light-sensitive tissue at the back of the eye responsible for sending visual information to the brain.
As a result of this improper light focusing, individuals with farsightedness experience difficulty seeing objects up close. In more severe cases, even distant objects can appear blurred. Symptoms include eyestrain, headaches, and blurred vision, especially when reading or using digital devices.
How LASIK Corrects Farsightedness
LASIK corrects farsightedness by precisely reshaping the cornea using an excimer laser. The procedure begins with the creation of a thin, hinged flap on the corneal surface, using a microkeratome blade or a femtosecond laser. This flap is then gently lifted to expose the underlying corneal tissue.
Unlike the correction for nearsightedness, which involves flattening the cornea, LASIK for farsightedness aims to make the central cornea steeper. The excimer laser ablates, or removes, microscopic amounts of tissue in a circular pattern around the central optical zone. This targeted removal of tissue increases the curvature of the cornea, thereby increasing its focusing power.
The goal of this reshaping is to properly redirect incoming light rays so they converge directly onto the retina, rather than behind it. Once the laser ablation is complete, the corneal flap is carefully repositioned, where it naturally adheres without the need for stitches, allowing for rapid healing.
Candidacy and Limitations for Farsightedness Correction
Suitability for LASIK depends on several individual factors. Patients typically need to be at least 18 years old, with some practitioners recommending waiting until the mid-20s to ensure vision stability. A stable prescription, meaning no significant changes for at least one to two years, is also required.
The degree of farsightedness that can be treated with LASIK is generally limited, typically to prescriptions up to +6.00 diopters. Higher degrees of hyperopia present greater challenges and less predictable outcomes. Corneal thickness is another important consideration; the cornea must be thick enough for the necessary reshaping while maintaining its health and structural integrity. An average thickness between 540 µm and 560 µm is suitable.
Factors that may disqualify a candidate include certain eye diseases such as keratoconus, severe cataracts, glaucoma, or active eye infections. Uncontrolled systemic health conditions like diabetes or autoimmune diseases can also affect healing and may make LASIK less suitable. Women who are pregnant or recently postpartum should postpone LASIK due to hormonal fluctuations that can temporarily affect vision.
Outcomes and Potential Risks for Farsightedness
LASIK for farsightedness can lead to significant improvements in uncorrected vision. Many patients achieve 20/40 vision or better, which often allows them to drive without corrective lenses. While not all patients achieve perfect 20/20 vision, the procedure frequently reduces dependence on glasses or contact lenses.
Like any surgical procedure, LASIK for farsightedness carries risks and side effects. One common concern is regression, where vision gradually returns to its original state over time. This is more common with hyperopic LASIK than with myopia correction. Temporary dry eyes are a common side effect after surgery, though this typically improves with time and the use of lubricating eye drops.
Other visual disturbances include glare, halos, or starbursts around lights, especially at night. These effects usually diminish within a few weeks but can persist. Flap-related complications, though rare, can also occur. Patients should have realistic expectations and discuss all outcomes and risks with their surgeon.