Anterior Stromal Puncture

From EyeWiki


Anterior stromal puncture is a simple yet effective procedure to treat patients with recurrent corneal erosion.

Disease Entity

Anterior stromal puncture in recurrent corneal erosion.

Disease and Etiology

Recurrent corneal erosion (RCE) is a disease characterized by repeated episodes of dislodgement of corneal epithelium from the underlying basement membrane due to loosened adhesion between the two layers. Patients who suffer from RCE will experience pain, photophobia, tearing, redness and a drop in vision, classically when they are awake from sleep, due to friction exerted on the corneal epithelium. This painful attack usually comes back--thus the name of the disease. RCE is usually secondary to a corneal abrasion caused by a sharp object (e.g. fingernail, paper) or secondary to an anterior corneal dystrophy (e.g. Map-dot fingerprint dystrophy, Reis-Bucklers).

Risk Factors

Risk factors include superficial corneal injury or anterior corneal dystrophy.

Diagnosis

Recurrent corneal erosion is diagnosed clinically. Patients may give a history of trauma or injury to cornea and recover afterwards. Later they develop spontaneous recurrent attacks of acute eye pain, tearing, foreign body sensation and photophobia, typically at the time of awakening. Clinical examination shows loose corneal epithelium or an epithelial defect which stains positive with fluorescein dye.

Patients are also examined to determine if they have any signs of anterior corneal dystrophy e.g. microcysts in Map-dot fingerprint dystrophy.

Differential diagnosis

Bacterial or fungal keratitis, corneal ucler, bullous keratopathy or herpetic dendritic keratitis may present with pain and epithelial defect.

Management

There are many different choices to treat recurrent corneal erosions, for instance, lubricants, eye patching, therapeutic bandage contact lens or autologous serum. However, the above treatment options are not definitive as they do not strengthen the adhesion between epithelium and underlying basement membrane (except autologous serum which contains fibronectin and may promotes epithelial cell migration and anchorage).

Anterior Stromal Puncture

It is noted that recurrent corneal erosion occurs in patients with superficial corneal abrasion but rarely occurs in patients with corneal laceration or penetrating injury. It is believed that injury in Bowman membrane causing scarring may actually enhance the adhesion of the overlying epithelium.


McLean was the first to describe anterior stromal puncture (ASP) in 1986.[1] A 20-gauge needle was used to puncture perpendicularly to cornea, through loose epithelium and Bowman's layer deep into the anterior half of the stroma. Approximately 15–25 punctures were spaced 0.5 mm to 1 mm apart.


However, nowadays, we no longer use such large bore needle sizes and we tend to puncture less deep to prevent corneal perforation and minimize scarring. Rubinfeld suggested using a bent needle with a smaller gauge (27-gauge or 30-gauge) for anterior stromal puncture. It was also found that an insertion depth of 0.1 mm was enough to cause fibrocytic reaction.


Before anterior stream puncture, topical anesthetics eye drops are given. The tip of the 27 or 30 gauge needle is bent. The mid-shaft of the needle is bent in opposite direction (forming Z-shape needle) so that the patient will not see the needle and hence this serves to decrease anxiety. Micropuncture down to Bowman’s layer is applied within the area of corneal erosion and away from the visual axis. Around 20 punctures are made with space 1mm or more apart.

Nd:YAG Laser Stromal Puncture

Geggel proposed the usage of Nd:YAG laser to create anterior corneal stromal micropuncture.[2]It is believed that laser punctures are more reproducible, shallow, and translucent. Laser was focused at the basement membrane zone after epithelial debridement. The energy level was between 1.8 and 2.2 mJ and spots were placed 0.20 to 0.25 mm apart. Katz et al used 0.4–0.5 mJ pulses to treat Bowman's layer through an intact epithelium.

Recently, Tsai evaluated the clinical outcomes of anterior stromal puncture with Nd:YAG laser in 33 eyes of 33 patients with unilaterally recurrent corneal erosion.[3] Anterior stromal puncture by Nd:YAG laser was performed in the loosened epithelial area or epithelial defect area without epithelial debridement. Energy settings were 0.3 to 0.6 mJ per shot and the laser was focused into the corneal subepithelium or superficial stroma. The number of spots applied ranged from 9 to 121, depending on the surface area of the loose epithelium. 49% of patients were completely symptom-free during 1.5 years follow-up after laser treatment, 36% eyes had subjectively mild symptoms but no macroform erosion, and 15% eyes had recurrence with documented corneal epithelial defects. Frequency of attacks significantly decreased in both the symptoms only and with macroerosion recurrence groups. In these groups, the preoperative and postoperative pain scores during attacks were compared and the subjective pain scores were all decreased after laser treatment.

Superficial Keratectomy

Debridement of the loose corneal epithelium, otherwise termed superficial keratectomy (SK), may be necessary to allow for proper healing of the affected corneal epithelium. This is typically done in conjunction with either phototherapeutic laser keratectomy (PTK) or diamond burr polishing (DBP) of the basement membrane. Both techniques may be more effective at achieving long term success than stromal puncture and are the treatments of choice for large erosions or erosions that involve the visual axis (where stromal puncture is contraindicated due to resultant scars). Most patients with corneal dystrophies will need an SK procedure rather than simply anterior stream puncture. Of the two techniques, DBP is cheaper and simpler, as PTK requires access to an excimer laser.

Following SK procedures, patients are placed in bandage contact lenses or, at the physicians discretion, a self-retained amniotic membrane, to enable healing of the corneal epithelium while protecting the surface from the friction and micro trauma of blinking. Aggressive lubrication with preservative-free tears is encouraged during the healing process.

Complications

Corneal perforation, corneal scarring, astigmatism. However, the risks are low. Another complication is recurrence of disease.

Prognosis

Prognosis is good. With needle anterior stromal puncture and laser stromal puncture, the success rate is up to 85%. With superficial keratectomy procedures using PTK/DB, the success rate may approach 90%.

Additional Resources

References

  1. McLean EN, MacRae SM, Rich LF. Recurrent erosion. Treatment by anterior stromal puncture. Ophthalmology. 1986 Jun;93(6):784-8.
  2. Geggel HS. Successful treatment of recurrent corneal erosion with Nd:YAG anterior stromal puncture. Am J Ophthalmol. 1990 Oct 15;110(4):404-7.
  3. Tzu-Yun Tsai. Recurrent Corneal Erosions Treated with Anterior Stromal Puncture by Neodymium: Yttrium–Aluminum–Garnet Laser. Ophthalmology. 2009;116:1296–1300
  1. Sujata Das. Recurrent Corneal Erosion Syndrome. Survey of Ophthalmology Volume 53, Issue 1, January-February 2008, Pages 3-15
  2. Sonmez; Amniotic Membrane Transplantation With Anterior Stromal Micropuncture for Treatment of Painful Bullous Keratopathy in Eyes With Poor Visual Potential. Cornea Volume 26(2), February 2007, pp 227-229
  3. Sridhar M, Rapuano CJ, Cosar CB, Cohen EJ, Laibson PR. Phototherapeutic keratectomy versus diamond burr polishing of Bownan's membrane in the treatment of recurrent corneal erosions associated with anterior basement membrane dystrophy. Ophthalmology. 2002 Apr;109(4):674-9.