A 27-year-old male was presented to the Bochner Eye Institute with a desire to improve his uncorrected vision. His preoperative assessment revealed:
Refractive Error:
- Right Eye: -4.75 -1.00 x 85
- Left Eye: -5.00 -1.25 x 75
Both eyes corrected to 20/20 visual acuity.
Corneal Thickness:
- Right Eye: 560 µm
- Left Eye: 550 µm
Corneal Topography: Normal
After a thorough discussion of risks and benefits, LASIK was performed using a femtosecond laser platform with no intraoperative complications. On postoperative day one, the patient was noted to have moderate bilateral DLK.
Postoperative Visual Acuity:
- Right Eye: 20/20
- Left Eye: 20/25
Topical Pred Forte was increased from QID to hourly during waking hours. The patient was monitored daily over the next six days, with gradual resolution of DLK in both eyes. Intraocular pressures remained within normal limits throughout treatment. Steroids were tapered and discontinued over a two-week period. There was no corneal haze, and final uncorrected acuity was 20/20 in both eyes.
CLINICAL FINDINGS:
1. DIFFUSE LAMELLAR KERATITIS (DLK):
Definition: A non-infectious complication of lamellar surgeries (e.g., LASIK, SMILE).
Presentation:
- Typically appears on the first postoperative day.
- Characterized by fine white cellular infiltrates in the corneal interface, resembling “Sands of Sahara.”
- Symptoms: Depends on the stage. Stage 1 and 2: Asymptomatic to mild blurred vision, no significant pain or photophobia.
- Differential Features: No keratic precipitates or hypopyon.
2. DIFFERENTIAL DIAGNOSIS:
Corneal Infection:
- Symptoms: Significant pain, photophobia, white infiltrate, keratic precipitates, and possible hypopyon.
- Requires flap lift, culture, and frequent broad-spectrum antibiotics.
Meibomian Secretions:
- Larger deposits than DLK, usually non-inflammatory.
- Require no treatment, usually does not affect vision, and may decrease over time.
3. STAGES OF DLK:
- Appearance: Fine, white, granular cells at the flap periphery.
- Location: Just beneath the flap in the interface, not affecting the visual axis.
- Common Mistake: Often mistaken for meibomian secretions or interface debris.
- Real image Notes: Best visualized using retroillumination; appears as a faint snow-dusting at the edge.
- Appearance: Infiltrates begin to migrate centrally.
- Location: Near or into the pupillary zone.
- Clinical Note: Visual acuity may begin to decrease slightly.
- Slit Lamp: Hazy central interface with small dots, still relatively clear margins.
- Appearance: Large, white, confluent infiltrates centrally.
- Effect: Causes significant visual disturbance.
- Slit Lamp: Flap appears diffusely hazy; edges may be indistinct; white plaques form a “snowstorm” pattern.
- Appearance: Dense, white opacification; signs of stromal thinning.
- Consequence: May result in permanent scarring or hyperopic shift.
- Slit Lamp: Central gray-white dense opacity, sometimes with visible flap striae or irregularity.
4. ETIOLOGY:
- Commonly triggered by epithelial injury during or after lamellar surgery.
- Other causes include retained blood, bacterial endotoxins, powder from surgical gloves, marking pens, surgical drapes, or other foreign substances in the interface.
- Patients with epithelial defects post-surgery have a 24-fold increased risk of DLK.
5. MANAGEMENT:
- Mild to Moderate DLK: Topical corticosteroids are effective.
- Severe DLK: May require flap lift, interface irrigation, repositioning, intense topical corticosteroids, and consideration of oral steroids.
- Prompt treatment minimizes complications.
FINAL THOUGHTS:
DLK remains one of the most important early postoperative considerations following LASIK. Although often mild and self-limited, it requires prompt recognition and treatment to avoid permanent visual consequences. This case highlights a typical presentation of bilateral moderate DLK that resolved fully with timely steroid escalation and close monitoring, resulting in an excellent visual outcome of 20/20 in both eyes.
Understanding the stages, differential diagnoses, and management strategies is essential for optimizing patient outcomes. With modern low-energy femtosecond laser platforms, the overall incidence of DLK remains low, and the majority of cases are effectively managed without long-term sequelae. However, vigilance is necessary, especially in the early postoperative period, to detect and treat DLK before it progresses to more advanced stages.
Ongoing education, careful surgical technique, and a proactive approach to early signs of interface inflammation continue to be the cornerstones of successful LASIK outcomes.
