New York Lasik Surgery

There are several adverse effects that may be encountered early in the post-operative period. These may include but not be limited to: foreign body sensation, pain or discomfort, sensitivity to bright lights, blurred vision, dryness of the eyes, tearing and fluctuation in vision. Persistent pain is uncommon following LASIK surgery and may indicate a disturbance of the epithelial protective layer, displacement of the corneal flap or possible infection and should be evaluated promptly by your doctor. Corneal infection following LASIK surgery is rare but very serious and can potentially result in corneal scarring requiring a corneal transplant and in very severe cases, infections can even result in blindness. Corneal inflammation can also be produced from medication or abnormal healing reactions, which may be allergic, toxic or autoimmune in nature. Diffuse interface keratitis (also known as Sands of the Sahara) is the most important inflammatory reaction and can produce corneal hazing, blurred vision, farsightedness, astigmatism and may result in permanent corneal irregularities. Treatment may involve topical steroids or further surgery and may or may not restore vision fully. The most common long-term side effect is dryness of the eyes. Many patients who elect to undergo LASIK surgery suffer from an underlying dry eye syndrome that results in poor contact lens tolerance and shorter wearing times. LASIK surgery may exacerbate these conditions either short term or in rare cases permanently. The most common long-term side effect is night glare, starbursting, haloes or simply reduced visual quality under low light conditions. It is very common to have night glare early during the recovery course and night glare is more common when only one eye has been treated. In most cases this gradually improves and does not impair the individual or prevent driving at night. Night visual disturbances are typically produced by the pupil size exceeding the laser treatment area. It is more common in nearsighted patients with severe prescriptions and large pupils. Some patients benefit from night driving glasses and most, but not all, patients improve substantially over 6 to 12 months. In a small percentage of patients night glare may be permanent and affect your night driving abilities.

Refractive problems that may be encountered include too much correction, too little correction, a prescription imbalance between eyes, aggravation of muscle imbalance problems or a loss of effect from regression. LASIK surgery may result in overcorrections and undercorrections due to the variability in patient healing patterns and other surgical variables, leaving patients nearsighted, farsighted or with astigmatism. This may or may not require patients to wear spectacles or contact lenses or to undergo further surgery. Further surgery entails additional risk and is not guaranteed to provide a perfect visual outcome. However, significant improvement is typically achieved following enhancement surgery. Patients may also heal differently between eyes, based upon differences between eyes in pre-operative prescriptions, corneal curvature, variation in healing or other surgical variables. Differences in refraction between eyes is termed anisometropia, which is most severe when only one eye treated, may result in a loss of depth perception, eyestrain, headache, double vision and the need for contact lenses. Both farsightedness and anisometropia may result in worsening of muscle balance problems, causing an eye to wander more or produce eye fatigue. Lastly, depending upon the severity of the original prescription, the individual healing pattern of the patient and other surgical variables, regression may occur, causing the eyes to return toward their original prescription, partially or, very rarely, completely. Further enhancement surgery may be performed when medically stable if adequate corneal tissue is available and no other medical contraindications are present. As stated previously, enhancement surgery, while generally very effective, is associated with additional risk and is not guaranteed to achieve the ideal visual result.

The primary benefits of LASIK surgery are related to the creation of the protective corneal flap. The corneal flap must be of clinically adequate quality, thickness and size to proceed with laser treatment. Corneal flap complications range in severity from those that simply require the procedure to be postponed by 3 to 6 months, to those that create significant corneal irregularities resulting in blurred vision. The most severe LASIK surgery complication is that of corneal perforation which has been reported several dozen times worldwide. Corneal flap complications that occur after the LASIK surgery procedure during the recovery period include displacement and wrinkling of the corneal flap and epithelial ingrowth.

• Corneal flaps of inadequate size, typically too small, preventing laser treatment and requiring the LASIK surgery procedure to be repeated in 3 to 6 months. Typically there is no serious visual disturbance, although glare and shadowing may occasionally be produced.
• Corneal flaps of inadequate thickness may or may not be adequate for laser treatment, and may result in the procedure being stopped and repeated after 3 to 6 months. A thin corneal flap may result in a slow visual recovery over weeks to months and possibly permanently blurred vision with or without laser treatment. Thin flaps can cause a loss of best-corrected visual acuity that cannot be repaired with further laser surgery.
• Corneal flaps of inadequate quality or smoothness, include a variety of corneal flap problems which may produce serious permanent corneal irregularities and significant visual blurring. Corneal flap irregularities may be produced because of inadequate suction pressure, inadequate orbital size, inadequate patient cooperation, malfunction or problems with the microkeratome, blade or suction apparatus. Corneas that are steeper or flatter than average are at greater risk for flap complications.
• Corneal flaps are routinely hinged either nasally or superiorly beneath the upper eyelid. A corneal hinge is not required for a good visual result, but a hinged corneal flap is more secure and typically heals faster and more smoothly. Depending upon the corneal shape, the suction ring alignment and the microkeratome, it is possible that a free corneal cap may be produced which is not hinged to the cornea. Although the laser treatment can still be performed, if any irregularities in flap quality or thickness are noted, the corneal disc is immediately replaced and allowed to heal. If the free corneal cap is of excellent quality, then the procedure is completed, but special care must be taken during the first 24 to 48 hours not to displace or lose the corneal cap. Loss of the corneal cap may result in scarring, permanent corneal irregularity and the need for more invasive surgery.
• Corneal perforation is the most serious LASIK surgery complication. Corneal perforation is prevented by the microkeratome depth plate, which is checked before each and every procedure. Some microkeratome have fixed corneal depth plates. Perforation of the cornea requires corneal suturing and the need for an intraocular lens implant, as the natural lens is usually lost or damaged. It should be appreciated that corneal perforation may also potentially result in infection, the need for a corneal transplant or, rarely even, blindness.
• Corneal flap displacement, partial or complete, occurs during the early post-operative period, typically during the first 12 to 24 hours, but may occur days to weeks later with trauma. Care should be taken to protect the eyes from trauma, as well as to avoid rubbing the eyes or forcefully closing the eyes during the first week after LASIK surgery. Partial displacement of the corneal flap may result in corneal striae or wrinkles, which blurs vision both qualitatively and quantitatively. Most corneal striae are treatable but some may be resistant to treatment, especially in highly nearsighted patients. Complete displacement of the corneal flap is often painful and requires urgent replacement. There is a higher risk of epithelial ingrowth and infection with corneal flap displacement.
• Epithelial ingrowth occurs during the first month following LASIK and is more likely to occur in patients with an abnormal or weakly adherent protective layer, for which age is a factor. Epithelial ingrowth is produced when the epithelial surface cells from the outer corneal layer grow underneath the corneal flap during the healing of the corneal flap incision. Epithelial ingrowth is more common with any trauma or breakdown of the epithelium, which is more common in LASIK surgery enhancement procedures and long-term contact lens wearers. Treatment of this condition involves lifting the flap and clearing the cells away. Although most small areas of epithelial ingrowth need only be monitored, untreated large areas of epithelial ingrowth may distort vision and may actually damage the flap integrity if severe and progressive. There is an increased incidence of epithelial ingrowth following enhancement surgery.

The protective corneal flap of LASIK surgery reduces the healing time of LASIK refractive surgery compared to PRK, but significant healing is still required which can affect the quality and vision of the final result. Corneal healing problems with LASIK surgery are more likely to be experienced by patients corrected for higher degrees of nearsightedness, farsightedness and astigmatism, which may potentially slow visual recovery and increase the need for enhancement procedures for over- and under-corrections. Corneal healing may affect not only the speed of visual recovery but the smoothness and may produce visual blurring. Rarely, corneal scarring may be produced with LASIK surgery. The most important aspect of corneal healing following LASIK surgery or any other form of refractive surgery is the development of corneal irregularities which may permanently affect the quality, crispness and sharpness of the final visual result. Corneal irregularities, or irregular astigmatism, are produced when the cornea heals in an irregular pattern, which may or may not follow a surgical flap complication. Corneal irregularity may also be produced from abnormalities and complications of the laser treatment, including central islands and decentration of the ablation. Either of these problems may produce blurring, shadowing, glare and double vision. Some corneal irregularity is commonly expected for the first several weeks or even months following an uncomplicated LASIK surgery procedure. However, if it persists beyond 6 months it is considered abnormal and may be permanent. Most corneal irregularities improve over 6 to 12 months. Some causes of corneal irregularity may be surgically managed but other causes are permanent. The greatest limitation of healing problems is that further surgical intervention does not guarantee better healing and may in fact result in a further reduction of visual quality. Irregular astigmatism from both healing and surgical complications may result in a loss of best corrected vision, which means that a patient may be unable to read the bottom few lines of the eye chart even with spectacle or contact lens correction. Specifically, the best vision a patient measures after surgery even with glass correction may not be as good as the patient experienced before refractive surgery. In certain cases, the vision may be severely impaired and affect the ability of a patient to drive legally. This is most important in patients who already have reduced visual acuity from other causes. That is, LASIK surgery is not intended to increase the visual potential of a patient. Many candidates with high prescriptions who often are unable to read 20/20 before surgery, even when corrected with glasses or contacts, should not expect to read 20/20 after surgery. Furthermore, a patient who is best corrected before surgery to 20/40 is already borderline for legal driving and any loss of best corrected vision from healing or surgical complications may prevent legal driving. Corneal healing is very patient specific and plays a critical role not only in how well a patient recovers from a surgical flap complication but in how rapidly and smoothly all patients recover.

It is important to note that it is impossible to list every conceivable complication that is not listed above. Risks and complications that are considered to be unforeseeable, remote or not commonly known are not discussed. In addition, there may be long-term effects not yet known or anticipated at the present time. Ectasia or bulging of the cornea has been reported in cases of excessive tissue removal. The most severe possible complications would necessitate more invasive or repeated corneal surgery, including corneal transplantation, and could potentially produce partial or complete loss of vision.