Anterior Stromal Puncture

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Article initiated by:

Michelle Fan, MBBS, MRCS Ed (Ophth)

All contributors:

Brad H. Feldman, M.D., Vatinee Y. Bunya, MD, MSCE, Matthew Nguyen, Sumayya Ahmad, MD, Michelle Fan, MBBS, MRCS Ed (Ophth)

Assigned editor:

Sumayya Ahmad, MD

Review:

Assigned status Update Pending

 by Sumayya Ahmad, MD on March 21, 2024.

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

Disease Entity

Anterior stromal puncture for the treatment of recurrent corneal erosion.

Disease and Etiology

Recurrent corneal erosion (RCE) is a disease characterized by repeated episodes of dislodgment 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 awaken from sleep, due to friction exerted on the corneal epithelium from the eyelid. This painful attack can sometimes recur, thus the name of the disease. RCE can sometimes occur secondary to a corneal abrasion from 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 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, bullous keratopathy or herpetic dendritic keratitis may present with pain and an epithelial defect.

Management

There are many different ways to treat recurrent corneal erosions. Management usually includes 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

Interestingly, recurrent corneal erosions occur in patients with superficial corneal injuries but rarely occurs in patients with corneal laceration or penetrating injury. It is believed that injury to Bowman's membrane causing scarring may enhance the adhesion of the overlying epithelium.

McLean was the first to describe 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.

More recently, larger bore needles are less likely to be used 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. An insertion depth of 0.1 mm was found to cause a fibrocytic reaction. Others have reported success with 25 gauge needles with a similar 0.5-1.0 mm apart, and 5-10% stromal depth approach.

The procedure is performed as follows: Before anterior stromal puncture, topical anesthetic eye drops are given. The tip of a small gauge needle is bent. The mid-shaft of the needle is bent in the opposite direction (forming a Z-shape) so that the patient will not see the needle. Micropuncture down to Bowman’s layer is applied within the area of corneal erosion and away from the visual axis (usually the center 3.0 mm of the cornea). Around 20 punctures are made with space 1mm or more apart and 5-10% stromal depth. Care is taken to avoid wide, horizontal scratches. The aim is to place small vertical punctures.

Nd:YAG Laser Stromal Puncture

Geggel proposed the usage of the Nd:YAG laser to create anterior corneal stromal micropunctures.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 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).

Following SK procedures, patients are placed in bandage contact lenses 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.

Diamond Burr Polishing

Diamond burr polishing, in conjunction with superficial keratectomy, has also demonstrated efficacy with treating RCE. One case series demonstrated 95% efficacy at treating RCE at 31 months. The method of the case series involved using a 3.3 mm diamond burr (after superficial keratectomy), and polishing for 30 seconds. In general, it is advisable to continue moving the burr during the treatment and if the cornea becomes dry, to re-wet it. This method can prevent haze and scarring. A BCL should be placed and antibiotics and steroid drops given for 3-4 weeks, with more steroids given if haze occurs.

Complications

Corneal perforation, corneal scarring, astigmatism. However, the risks are low. Another complication is recurrence of disease and need for further interventions.

Prognosis

Prognosis is good. With needle anterior stromal puncture and laser stromal puncture, the success rate can be up to 85%. With superficial keratectomy procedures using PTK/DB, the success rate may approach 95%. A study comparing outcomes of stromal micropuncture, photo therapeutic keratectomy, and superficial keratectomy with diamond burr polishing demonstrated a recurrence rate of 30%, 10%, and 9%, respectively.

Additional Resources

• Corneal Erosion. American Academy of Ophthalmology. EyeSmart/Eye health. https://www.aao.org/eye-health/diseases/corneal-erosion. Accessed March 28, 2019.