Anterior Stromal Puncture

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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 suffer from RCE will experience pain, photophobia, tearing, redness and 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 corneal abrasion caused by sharp object (e.g. fingernail, paper) or 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 loosen corneal epithelium or epithelial defect which stains positive with fluorescein dye.

We also have to exam if patients 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 (except autologous serum as there is fibronectin which 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 who described anterior stromal puncture (ASP) in 1986. 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 size needle and we tend to puncture less deep to prevent corneal perforation and minimize scarring.
Rubinfeld suggested using a bent needle with 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.
We first applied local anesthetics eye drops to the disease eye. The tip of the 27 or 30 gauge needle is bent. We can bend the mid-shaft of the needle in opposite direction (forming Z-shape needle) so that patient would not see the needle and hence decrease anxiety. Micropuncture deep down to Bowman’s layer is applied to area of corneal erosion and it should be away from 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. 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. Anterior stromal puncture by Nd:YAG laser was performed in the loosened epithelial area or epithelial defect area without epithelial debridement. Energy setting of was 0.3 to 0.6 mJ per shot and was focused in corneal subepithelium or superficial stroma. The number of spots applied ranged from 9 to 121, depending on the surface area of the loosening 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, 15% eyes had recurrence with documented corneal epithelial defects. Frequency of attacks significantly decreases in both the symptoms only and with macroerosion recurrence groups. And in these groups, the preoperative and postoperative pain score during attack were compared and the subjective pain scores were all decreased after laser treatment.


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%.

References

1. Recurrent Corneal Erosion Syndrome; Sujata Das; Survey of Ophthalmology Volume 53, Issue 1, January-February 2008, Pages 3-15
2. Amniotic Membrane Transplantation With Anterior Stromal Micropuncture for Treatment of Painful Bullous Keratopathy in Eyes With Poor Visual Potential;Sonmez; Cornea Volume 26(2), February 2007, pp 227-229
3. Recurrent Corneal Erosions Treated with Anterior Stromal Puncture by Neodymium: Yttrium–Aluminum–Garnet Laser; Tzu-Yun Tsai; Ophthalmology 2009;116:1296–1300

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