OD News Articles

10th July 2018

Managing Lasik Complications

by Alexander Archibald, OD Boise, ID

With PCLI’s unwavering commitment to Optometry, we’ve had the privilege of performing over 95,000 LASIK procedures for referred patients. The surgery’s high success rate has made LASIK very popular, and most patients are thrilled with their new vision. Although the risks associated with LASIK are low, complications are always possible. Even when the procedure is flawless, problems can present in the early post-operative period. Understanding how to detect and manage these complications will help ensure the best outcomes for your patients.

The Aviso scanning instrument

Let’s review three possibilities. If LASIK is a significant part of your practice, you may have managed one or all of these conditions:

  1. Corneal striae
  2. Diffuse lamellar keratitis (DLK)
  3. Epithelial ingrowth
Corneal Striae

Microstriae present as fine wrinkles in the LASIK flap. Occasionally, more prominent folds are encountered. They are usually the result of mechanical impact such as rubbing or bumping the eye shortly after surgery. Severe striae can cause ghosting and poor quality vision. Striae are best visualized by indirect slit lamp illumination or by retro-illuminating the cornea. Fluorescein dye may assist with identification of mild cases.

Causes

  • Inappropriate manipulation of the flap
  • Internal stresses of the flap
  • Unstable flap
  • Trauma
    Normal B-scan
    Severe striae 1 day after LASIK. The patient inadvertently touched the flap with the tip of a medication bottle. UCVA was 20/80 and BCVA was 20/60. The flap was lifted and repositioned and protected with a bandage contact lens for 1 day. No striae visible the following day. UCVA and BCVA was 20/20.

    Source: www.usaeyes.org

Mild Cases

  • More common in patients with a high myopic correction because the deeper laser ablation results in a stromal bed that is slightly flatter than the curvature of the corneal flap
  • Usually not visually significant
  • No treatment required unless BCVA is decreased or a gap at the flap edge exists
  • Simply evaluate and document

Severe Cases

  • Fairly Uncommon
  • BCVA is decreased due to involvement of the central cornea
  • Refer patient to surgeon for flap refloat
Diffuse Lamellar Keratitis (DLK)

DLK is thought to be a sterile inflammatory reaction to antigens in the corneal interface. A haze of white blood cells extends inward from the corneal limbus with no specific pattern. It can involve the periphery or entire cornea. When the condition is most prominent, slit-lamp examination shows fine, white and grainy cells that look like waves of sand. For this reason, DLK is often described as sands of Sahara syndrome. It can be difficult to diagnose in the immediate post-op period.

Cause

  • Although a number of theories have been researched and discussed, the specific cause is unknown.
  • Patients with allergies tend to be the most vulnerable.

Signs and Symptoms

  • Usually 1–6 days after surgery, a haze appears in the corneal interface extending from the limbus with associated bulbar conjunctival injection.
  • At the time of earliest onset, patients may not complain of discomfort and will often have good vision.
  • Discomfort, blurred vision, foreign body sensation, and sensitivity to light often develop in untreated eyes.
    Four views of pathology on B-scan
    DLK 2 days after LASIK. The patient reported hazy vision, slight redness and light sensitivity in both eyes. UCVA was 20/25- and BCVA was 20/25+ in each eye. Pred Forte 1 drop q 1h OU was prescribed with resolving symptoms and signs after 1 week. This was tapered over 2 additional weeks until complete resolution of DLK, at which time UCVA was 20/20 in each eye.

Treatment

  • A regimen of frequent topical steroids is usually effective; typically 1 drop every 1 to 2 hours. Consider using Durezol vs. Prednisone Acetate, as it is stronger. But keep a careful watch on IOP.
  • Corneal inflammation should begin to resolve within 1 to 3 days, although treatment for a few weeks may be indicated.
  • If inflammation does not begin to resolve after 5 days, the patient should be referred back to the surgery center.
  • If significant inflammation persists after 5 to 7 days, the flap may need to be lifted and the interface cleaned.

The sooner DLK is diagnosed and treated the better the prognosis. Delayed treatment can result in scarring.

Epithelial Ingrowth

This condition occurs when epithelial cells migrate under the edge of the LASIK flap and grow toward the visual axis. Epithelial ingrowth is typically detected within 1 to 2 weeks of surgery. Peripheral cells may advance about 1 mm under the flap edge before it seals. They usually appear as an irregular white line concentric with the flap margin and are considered “non-aggressive”. The white line is a good sign indicating stability.

Cause

  • Patients with dry eye problems or poor corneal flap adherence have greater chance of epithelial ingrowth.

Signs and Symptoms

  • Ingrowth initially presents as a translucent haze along the flap margin, becoming more opaque (greyish white) with time.
  • As progression occurs, patients may report worsening vision, due to increasing astigmatism, and discomfort not relieved with artificial tears.
  • Nests of epithelial cells can appear as a peninsula-shaped, whorl-like opacification. Although these groups of cells may be non-progressive, they should be monitored for development of patient symptoms or compromised corneal health.
    Four views of pathology on B-scan
    Epithelial ingrowth 4 weeks after LASIK. The patient was asymptomatic although a mosaic pattern of whitish-appearing epithelium extended 2 mm into the corneal interface. Given the absence of symptoms and the otherwise healthy appearance of the cornea, the patient was monitored monthly. After 3 months the epithelial ingrowth was determined to be non-aggressive and no surgical intervention was required.

Treatment

  • No treatment is required if cells are stable and not visually significant.
  • Surgical intervention is generally needed in the few cases where ingrowth progresses further than 2 mm and is either affecting vision or integrity of the flap. Epithelial ingrowth is the most common complication to follow uncomplicated LASIK surgery. But aggressive ingrowth that requires intervention is rare. The best way to limit risk of this condition is to ensure a healthy corneal surface before LASIK.
Conclusion

Although uncommon, the three complications we have discussed are possible with femtosecond laser and microkeratome LASIK flaps. Without proper treatment, patients may suffer decreased vision or compromised ocular surface health. So it’s important to be familiar with these potential problems, treatment options and when surgical management may be needed.

Questions?

If you ever have questions, feel free to contact any of our optometric physicians. We’re always happy to help.

Normal UBM scan