Treatment of Diffuse Lamellar Keratitis (DLK)
The treatment of diffuse lamellar keratitis should be guided by the severity of inflammation, with mild cases managed by increased frequency of topical corticosteroids and more severe cases requiring aggressive steroid therapy or surgical intervention with flap lifting and interface irrigation. 1
Understanding DLK
Diffuse lamellar keratitis is a non-infectious inflammatory condition that occurs following LASIK surgery, characterized by:
- Inflammatory cell aggregation confined to the lamellar interface
- Fine granular reaction in the interface that can progress to "Sands of the Sahara" appearance
- Usually more prominent in the periphery
- Typically occurs in the first few days after surgery
- Patient generally has no discomfort, with little or no conjunctival hyperemia or anterior chamber inflammation 1
Staging-Based Treatment Algorithm
Stage I (Mild DLK)
- Increase frequency of topical corticosteroid administration
- Schedule closer follow-up
- These cases are generally self-limited with little visual consequence 1
Stage II (Moderate DLK)
- More frequent and/or higher concentrations of topical corticosteroids
- Consider systemic corticosteroids if not responding adequately 1
Stage III-IV (Severe DLK)
- Aggressive topical corticosteroids
- Systemic corticosteroids
- For significant central involvement, rapidly progressing DLK, or risk of stromal tissue loss: lift the flap with irrigation of the interface 1
- Consider direct application of corticosteroids to the exposed stromal interface 1
Preventive Measures
Before implementing treatment, prevention is crucial:
- Careful examination of external eye before surgery
- Strict cleaning and disinfection of the operative eye
- Proper disinfection of medical instruments
- Avoiding residual disinfectant
- Appropriate laser energy settings
- Gentle operative manipulation
- Avoiding repeated instrument insertion/removal
- Preventing oil and tear accumulation 1
Special Considerations
Persistent DLK
If unresponsive to corticosteroids, consider:
- Microbial keratitis
- Interlamellar fluid due to increased IOP (pressure-induced stromal keratitis)
- Intraocular inflammation
- Endothelial decompensation 1
Steroid-Related Complications
- Monitor for IOP elevation, especially in steroid responders
- Measure IOP peripheral to the flap edge for accurate readings
- Consider anti-glaucoma agents if IOP rises significantly 1, 2
Timing of Intervention
For extensive DLK, the interface should be irrigated sooner rather than later to minimize:
- Stromal loss
- Refractive shifts
- Irregular astigmatism 1
Differentiating DLK from Other Conditions
Central Toxic Keratopathy
- Non-inflammatory central/pericentral amorphous corneal opacity
- Occurs within nine days of LASIK
- Results in residual thinning, striae, and hyperopia
- Unlike DLK, steroids are not generally recommended 1
Microbial Keratitis
- Presents with pain, redness, photophobia (unlike DLK)
- Focal infiltrates that often extend beyond the interface
- Anterior chamber reaction usually present
- Requires flap lifting, scrapings for culture, and intensive antibiotic therapy 1
Evidence on Treatment Outcomes
High-dose topical and oral corticosteroids have shown excellent results in treating severe DLK without the need for flap lifting and interface irrigation in some studies 3. However, the most recent guidelines still recommend surgical intervention for severe cases with central involvement or rapid progression 1.
Key Pitfalls to Avoid
- Misdiagnosis of infectious keratitis as DLK
- Prolonged corticosteroid treatment in cases of pressure-induced stromal keratitis
- Delayed intervention in rapidly progressing cases
- Failure to monitor for steroid-related complications
- Inadequate follow-up of mild cases that may progress
Remember that DLK can recur idiopathically even a year after the initial episode, so vigilance during follow-up is essential 4.