Development and Evaluation of a Device for Sutureless and Repeated Application of Amniotic Membrane Overlays

Sutureless fixation of amniotic membrane using a soft ring for ocular surface diseases

PURPOSE

To evaluate the efficacy of sutureless amniotic membrane transplantation using a soft bioavailable ring in the management of ocular surface disorders.

METHODS

We present a modified technique using a soft, special designed bioavailable ring set (Amnioring) for sutureless amniotic membrane fixation to the ocular surface. A fresh amniotic membrane with a diameter greater than the outside diameter of the ring was folded inwardly over the ring such that the inner side of the ring was covered with the amniotic membrane. The ring was inserted onto the ocular surface.

RESULTS

The ring was inserted in 4 eyes of 4 consecutive patients with ocular surface disorders. The mean total operating time was 3 min. The ring fixated the amniotic membrane to the bulbar conjunctiva and provided a quick and easy sutureless placement of amniotic membrane. In all cases, pain was significantly relieved. The corneal epithelial defect and inflammation were markedly reduced.

CONCLUSIONS

This novel ring designed for sutureless placement of amniotic membrane provided very good anatomic and functional outcomes in patients with ocular surface disorders. It is less invasive, less time consuming and allows placement in the office conditions with low cost.

Sutureless "Contact Lens Sandwich" Technique for Amniotic Membrane Therapy of Central Corneal Ulcers

PURPOSE

To describe a new technique for sutureless and glue-free amniotic membrane transplantation (AMT) and to investigate its effectiveness to treat corneal persistent epithelial defects (PEDs), compared to bandage contact lens (BCL) application alone.

METHODS

We performed AMT with "contact lens sandwich technique" (CLS-AMT) in 8 consecutive patients with central/para-central (up to 4.00 mm from the geometrical centre) PED/ulceration and we retrospectively compared the results with 11 BCL procedures.

RESULTS

The procedures were performed successfully with no complications.CLS-AMT showed significantly shorter healing time than BCL (24.0  ±  19.1 vs 42.9  ±  14.6 days; P < 0.05, Mann-Whitney test). Recurrence rates were 12% and 27% for CLS-AMT and BCL, respectively.

CONCLUSION

CLS-AMT technique, based on the suction effect due to the superposition of a bandage contact lens on the AM-ring complex, represents a quick, low cost, easy to perform and nearly non-invasive AMT technique. This approach is able to provide adequate fixation of AM, and it seems to be a safe and effective treatment for patients with PEDs.

Wound healing in the eye: Therapeutic prospects

In order to maintain a smooth optical surface the corneal epithelium has to continuously renew itself so as to maintain its function as a barrier to fluctuating external surroundings and various environmental insults. After trauma, the cornea typically re-epithelializes promptly thereby minimizing the risk of infection, opacification or perforation. A persistent epithelial defect (PED) is usually referred to as a non-healing epithelial lesion after approximately two weeks of treatment with standard therapies to no avail. They occur following exposure to toxic agents, mechanical injury, and ocular surface infections and are associated with significant clinical morbidity in patients, resulting in discomfort or visual loss. In the case of deeper corneal injury and corneal pathology the wound healing cascade can also extend to the corneal stroma, the layer below the epithelium. Although significant progress has been made in recent years, pharmaco-therapeutic agents that promote corneal healing remain limited. This article serves as a review of current standard therapies, recently introduced alternative therapies gaining in popularity, and a look into the newest developments into ocular wound healing.

Long-term efficacy of glycerine-processed amniotic membrane transplantation in patients with corneal ulcer

PURPOSE

The aim of this study was to determine the long-term treatment efficacy of glycerine-preserved human amniotic membrane transplantation in patients suffering from corneal ulcers.

METHODS

This was a retrospective, non-controlled, monocentric analysis. Included were patients with corneal ulcers that were non-responsive to ointment or contact lenses and had been treated by amniotic membrane transplantation with either the overlay or sandwich procedure. Analysis parameters were visual acuity before and following treatment, recurrence rate and subjective comfort at the last follow-up.

RESULTS

Of the 371 amniotic membrane transplantations that were conducted, 135 surgical treatments in 108 patients (51.9% male, 48.1% female; mean age 63.7 years) met the inclusion criteria. In total, 99 overlay and 36 multilayer amniotic membrane transplantations were performed. The follow-up period was 47.5 ± 66.7 weeks (mean ± SD). The recurrence rate at the last follow-up was 47.8% with overlay membranes and 51.8% with the sandwich technique. There was no significant change in best-corrected visual acuity following treatment with overlays (p = 0.219) or sandwich procedure (p = 0.703). At the last follow-up, 72.1% (overlay) and 78.3% (sandwich) of the patients reported either no pain or increased comfort.

CONCLUSION

The recurrence rates and changes in visual acuity following overlay or sandwich amniotic membrane transplantation in patients suffering from corneal ulcer were lower than reported elsewhere in the literature. More than half of the patients profited from each of the amniotic membrane transplantation techniques with respect to recurrence and postoperative comfort.

Sutureless fixation of amniotic membrane for therapy of ocular surface disorders

Amniotic membrane is applied to the diseased ocular surface to stimulate wound healing and tissue repair, because it releases supportive growth factors and cytokines. These effects fade within about a week after application, necessitating repeated application. Generally, amniotic membrane is fixed with sutures to the ocular surface, but surgical intervention at the inflamed or diseased site can be detrimental. Therefore, we have developed a system for the mounting of amniotic membrane between two rings for application to a diseased ocular surface without surgical intervention (sutureless amniotic membrane transplantation). With this system, AmnioClip, amniotic membrane can be applied like a large contact lens. First prototypes were tested in an experiment on oneself for wearing comfort. The final system was tested on 7 patients in a pilot study. A possible influence of the ring system on the biological effects of amniotic membrane was analyzed by histochemistry and by analyzing the expression of vascular endothelial growth factor-A (VEGF-A), hepatocyte growth factor (HGF), fibroblast growth factor 2 (FGF 2) and pigment epithelium-derived factor (PEDF) from amniotic membranes before and after therapeutic application. The final product, AmnioClip, showed good tolerance and did not impair the biological effects of amniotic membrane. VEGF-A and PEDF mRNA was expressed in amniotic membrane after storage and mounting before transplantation, but was undetectable after a 7-day application period. Consequently, transplantation of amniotic membranes with AmnioClip provides a sutureless and hence improved therapeutic strategy for corneal surface disorders.