CASE OVERVIEW

A 24-year-old male presented for evaluation of refractive surgery. His refractive error was -7.25 -1.50 x 15 in the right eye and -6.75 -1.50 x 35 in the left eye, both achieving 20/20 corrected visual acuity. Corneal thickness measured 510 microns in the right eye and 508 microns in the left eye. Computerized topography showed no signs of irregular astigmatism, and the remainder of the eye examination was unremarkable.

After discussing the risks and benefits of laser vision correction, it was decided to proceed with Photorefractive Keratectomy (PRK) due to his relatively high refractive error and thinner corneas. While his anterior chamber depths of 2.8 mm (right eye) and 2.85 mm (left eye) qualified him for an implantable contact lens, the patient preferred a surface ablation procedure.

During surgery, a 9 mm area of epithelium was removed using a rotary brush, followed by laser ablation with the Allegretto 500 laser system with advanced tracking technology. At his one-day post-operative visit, his uncorrected visual acuity was 20/50 in the right eye and 20/40 in the left eye, with 50% epithelial healing observed. The patient opted to follow up with his local eye doctor for his five-day post-op visit. At that time, the epithelium was intact, but the doctor noted a corneal dendrite in both eyes and referred the patient back for further evaluation. Upon examination, the diagnosis of a pseudodendrite was confirmed.

KEY LEARNING POINTS:

1. PSEUDODENDRITE FORMATION:

  • Pseudodendrites are a common healing response after PRK or any corneal abrasion/erosion.
  • As the epithelium heals, epithelial cells from opposite sides of the defect meet, creating a heaped-up appearance resembling a corneal dendrite (see Figure A).

2. CLINICAL FEATURES:

  • Pseudodendrites differ from herpetic corneal dendrites caused by herpes simplex.
  • They are not associated with significant discomfort, light sensitivity, or pain, and there are no keratic precipitates. Herpetic dendrites typically feature terminal bulbs (see Figure B).

3. MANAGEMENT:

  • Antiviral therapy is unnecessary for pseudodendrites.
  • Epithelial irregularities smooth out naturally during healing, leading to improved vision without intervention.
  • Preservative-free artificial tears can support the healing process.

4. BEST UNCORRECTED VISION:

  • Optimal uncorrected vision post-PRK typically takes 2 to 4 months to achieve.
  • Even after pseudodendrite resolution, epithelial cells undergo thickening (hyperplasia) or thinning (hypoplasia) as the corneal surface smooths out.

5. FUNCTIONAL VISION AFTER PRK:

  • Around 95% of PRK patients achieve vision satisfactory for driving by five days, but improvement continues over several months.
  • Managing patient expectations is crucial for their understanding of the recovery process.