Seprafilm as a new antifibrotic agent following trabeculectomy in rabbit eyes.

PURPOSE: To investigate the efficacy of Seprafilm (Genzyme, Framingham, MA, USA) in preventing postoperative adhesion between the conjunctiva and sclera after glaucoma filtering surgery. METHODS: A subconjunctival pocket was created and Seprafilm was inserted into the pocket in nine rabbits (Seprafilm group), whereas in a second group, a subconjunctival pocket was created in nine rabbits but no Seprafilm was inserted (non-Seprafilm group). The postoperative adhesion force was measured 4 weeks after surgery. For the trabeculectomy study, trabeculectomy was performed and Seprafilm placed on the scleral flap in five rabbits (Seprafilm trabeculectomy group), whereas in a second group, trabeculectomy was performed in five rabbits but no Seprafilm was placed (non-Seprafilm trabeculectomy group). Filtering bleb formation and intraocular pressure (IOP) was evaluated on days 1, 3, 5, 7, 14, 21, and 28 following surgery. The eyes were enucleated for histologic evaluation 4 weeks after surgery. RESULTS: The mean adhesive force between the conjunctiva and sclera in the Seprafilm group (125.6 +/- 94.5 mmHg) was lower than that of the non-Seprafilm group (263.3 +/- 79.3 mmHg) (P = 0.0041, unpaired t test). A more prominent bleb was observed in the Seprafilm trabeculectomy group than in the non-Seprafilm trabeculectomy group. Histologically, the subconjunctival space was larger in the Seprafilm trabeculectomy group than in the non-Seprafilm trabeculectomy group. Mean IOP was significantly lower in the Seprafilm trabeculectomy group (9.9 +/- 0.6 mmHg) than in the non-Seprafilm trabeculectomy group (11.9 +/- 0.7 mmHg) 4 weeks after surgery (P = 0.0044, unpaired t test). CONCLUSIONS: Seprafilm can reduce postoperative conjunctiva-sclera adhesion and may be a desirable antifibrotic agent for trabeculectomy in the early stages of wound repair.

Intraocular use of hydrogel tissue adhesive in rabbit eyes.

PURPOSE: To evaluate the safety and efficacy of newly developed hydrogel glue to treat rhegmatogenous retinal detachments in in vitro and in vivo studies. METHODS: In the in vitro study, the solid hydrogel glue was soaked in a balanced salt solution (BSS). The pH was measured periodically, and the dissolution time was recorded. In the in vivo study in six albino rabbits, 0.1 ml of hydrogel glue was injected into the right vitreous cavity, and 0.1 ml BSS was injected into the left vitreous, as the control. Clinical, electroretinography (ERG) and histological examinations were performed. Retinal detachment with a retinal hole was created in 12 albino rabbits after vitrectomy. After fluid-air exchange, the hydrogel glue was applied to the hole in nine rabbits; three other rabbits were used as controls. Clinical and histological examinations were performed. RESULTS: The pH ranged from 6.65 to 8.14. The glue remained solid in BSS for 7 weeks. The glue injection did not induce inflammation. There was no significant difference between the study and control eyes in the ERG amplitude or the implicit times of the a and b waves. No significant histological abnormality was detected. The retina was reattached with glue in three of nine eyes. The histological examination showed glue under the retina. CONCLUSIONS: Hydrogel glue, which seemed to be minimally toxic to the eye, can be used to patch retinal breaks. However, methods to mix a small amount of each solution completely and a more effective intraocular delivery system for the glue are needed.

In vivo and in vitro feasibility studies of intraocular use of seprafilm to close retinal breaks in bovine and rabbit eyes.

PURPOSE: Seprafilm, a sodium hyaluronate/carboxymethylcellulose absorbable barrier developed to prevent adhesions after abdominal surgery, adheres well to wet tissue. The authors studied the efficacy of this film for sealing retinal breaks in animals. METHODS: In an in vitro study, a retinal detachment with a hole was created in bovine eyecups after the vitreous gel was removed. Seprafilm was placed over the retinal hole, and the strength of the retinal adhesion was measured by pulling the film. Permeability was tested by applying methylene blue to the film covering the retinal break. Seprafilm also was soaked in balanced salt solution (BSS) incubated at 37 degrees C, and the pH of the BSS containing Seprafilm was measured as it melted. In an in vivo study, Seprafilm was powdered and mixed in BSS solution, and 0.1 mL was injected into the right vitreous cavity in study rabbits. The same amount of BSS was injected into the right vitreous cavity in control rabbits. Ophthalmologic examinations were performed. Bilateral electroretinograms were recorded simultaneously before and 6 weeks after injection. Both eyes were enucleated for histologic evaluation. RESULTS: Seprafilm adhered well to the retina, was impermeable to methylene blue, and remained solid in BSS for 30 days before it dissolved, and its pH ranged from 7.2 to 8.0. No intraocular inflammatory reaction occurred after intravitreous injection of Seprafilm solution. There was no significant difference in amplitudes or implicit times of electroretinogram a-waves, b-waves, and oscillatory potentials before and after injection and between study and control groups. No significant retinal abnormality was detected by light microscopy in either group. CONCLUSIONS: The film adhered well to the retina with no signs of ocular toxicities. Further study is warranted for possible means of patching retinal breaks.