Corneal preparation of eye bank eyes for experimental surgery.

PURPOSE: To evaluate the efficacy of dextran in balanced salt solution (BSS) as a preparation of eye bank corneas for experimental surgeries. METHODS: We used 12 eye bank eyes that were unsuitable for transplant. The corneas were removed from the globe and affixed to a Hanna artificial anterior chamber. Four concentrations of dextran-BSS (10%, 15%, 20%, and 30% [+/-0.56%]) were used to dehydrate the corneas, and corneal thickness was assessed with an ultrasonic pachymeter (+/-5 microm) at varying time-intervals over 3 hours. RESULTS: The corneas were thinned to an average thickness of 477+/-54 microm, 430+/-54 microm, 406+/-61 microm, and 391+/-52 microm at average times of 75+/-0 minutes, 85+/-23 minutes, 60+/-12 minutes, and 45+/-0 minutes for the 10%, 15%, 20%, and 30% concentrations, respectively. Corneal thickness was stabilized in both a 15% and a 20% solution. The data was fit to exponential curves until a minimum value was reached, after which linear regression analysis was used to determine the slopes of the data. The slopes for the 15% and 20% concentrations were not significantly different from 0 (p = 0.5 and p = 0.4, respectively). The slopes for each set of data from the 10% and 30% concentrations were significantly different from each other (p = 0.010 and p = 0.001, respectively). CONCLUSIONS: A solution of 20% dextran in BSS is effective for dehydrating eye bank corneas to a quasi-normal physiologic thickness and for maintaining the thickness for a sufficient amount of time. Both the posterior and anterior sides of the cornea should be exposed to the solution for 60 minutes.

Use of human fibrin glue and amniotic membrane transplant in corneal perforation.

PURPOSE: To repair corneal perforation using human fibrin glue (HFG) and amniotic membrane transplant (AMT). METHODS: Three patients in whom central corneal perforations, approximately 2 mm in diameter, occurred after ocular or systemic disease were successfully cured using HFG and AMT. The technique consists first of using a high-viscosity sodium hyaluronate viscoelastic material to restore anterior chamber depth followed by a debridement of the ulcer. The perforation site is filled with the HFG to corneal surface level. The so-formed plug is then secured with an AMT to avoid its extrusion. An extended-wear bandage contact lens and topical antibiotics were used in these patients for 3 weeks. RESULTS: Total reepithelialization was observed after an average of 15 postoperative days. The AMT dissolved within 8 weeks to uncover a whitish scar formed within the perforation sites. No complications were observed in any patients. After a follow-up period of 195-325 days, all corneas remained stable; there was no infection or ulcer recurrence, but some corneal scar thinning was observed in all three cases. CONCLUSION: The described surgical approach using HFG and AMT allowed a successful repair of corneal perforations with a diameter of 2 mm associated with significant loss of stroma. This method may be a good alternative to delay penetrating keratoplasty for treating corneal perforations, especially in acute cases in which graft rejection risk is high. eal

Small peripheral anterior continuous curvilinear capsulorhexis.

Cataract surgery is routinely performed using an anterior continuous curvilinear capsulorhexis (CCC). A manual surgical technique is described for performing a small (less than 1.5 mm diameter) anterior CCC. This technique's applications extend from Phaco-Ersatz, a cataract surgical technique designed to restore accommodation to pediatric cataract surgery. An experimental rabbit study was conducted to determine the feasibility of the technique. Up to 9 small peripheral anterior CCCs were made in the same lens capsule without the capsule tearing. The mean diameter of the CCCs was 1.1 mm +/- 0.3 (SD). A 30 gauge needle and Utrata capsulorhexis forceps were used to construct the CCC. This technique shows promise for the successful performance of small CCCs in Phaco-Ersatz procedures and pediatric cataract surgery.

Reticulated hyaluronic acid implant in nonperforating trabecular surgery.

PURPOSE: To evaluate experimentally and clinically the tolerance and efficacy of a reticulated hyaluronic acid implant in nonperforating trabecular surgery (NPTS). SETTING: Bascom Palmer Eye Institute, Miami, Florida, USA, and Clinique Sourdille and Clinique Ophtalmologique Universitaire, Nantes, France. METHODS: In experimental surgery, NPTS was performed with and without a hyaluronic acid implant in 25 rabbit eyes. In a pilot study, the results of NPTS with a hyaluronic acid implant in 72 human eyes were retrospectively analyzed in terms of visual acuity, intraocular pressure (IOP), external filtration, postoperative inflammation, and gonioscopy. Mean follow-up was 13.8 months (range 6 to 24 months). RESULTS: In the experimental surgery, the rabbit eyes with the implant showed a different healing process than the eyes without the implant. The implant was slowly bioabsorbed and remnants were seen at the operative site (where the tissue was removed) up to day 56 postoperatively. This site was detectable at all histology study periods. Intraocular pressure reduction was longer in the implant group: greater than 5 months versus 3 weeks (P < .05). In the pilot study, visual acuity remained stable, IOP decreased from a mean preoperative level of 26.3 mm Hg +/- 5.22 (SD) to a mean postoperative level without treatment of 15.4 +/- 3.1 mm Hg (P < .0001). No external filtration was detected in 60 eyes, a slightly elevated conjunctiva was noted in 12 eyes. Postoperative inflammation (laser flare and cell measurements) was low. Gonioscopy consistently demonstrated the persistence of a decompression space behind the trabeculum. CONCLUSION: Comparative experimental surgery results showed excellent tolerance and efficacy in the rabbit eyes with a hyaluronic acid implant. Clinical results, to be confirmed by a randomized comparative study, also showed excellent biocompatibility and encouraging efficacy.

[Gel injection adjustable keratoplasty (GIAK). Keratometric evaluation on cadaver eyes]. / Gel injection adjustable keratoplasty (GIAK). Evaluation kératométrique sur yeux de cadavres.

To assess keratometric changes of a new refractive surgical technique (Gel Injection Adjustable Keratoplasty--GIAK) on Eye Bank eyes. The surgery consist of making an intrastromal annular delamination at 80% depth using customized delaminators. The tunnel is then filled with a crosslinked polyethylene oxide gel (PEO).

[Implantation of controlled-release 5-FU for the prevention of secondary cataract: preliminary study]. / Implant à relargage contrôlé de 5-FU pour la prévention de la cataracte secondaire: étude préliminaire.

To assess the efficacy of a control drug release implant coated with 5-Fu placed in the capsular bag for the prevention of the secondary cataract.

[Keratoprosthesis by posterior fixation and mechanical biocompatibility: determination of intraocular pressure provoking aqueous humor leak and/or extrusion]. / Kératoprotheses à fixation postérieure et biocompatibilité mécanique: détermination de la pression intraoculaire provoquant une fuite d'humeur aqueuse et/ou une extrusion.

The effect of a sudden increase in intraocular pressure (IOP) on Eye Bank eyes implanted with a posterior fixation keratoprosthesis PCL5 type (Lacombe) is evaluated. The IOP was artificially increased at a rate close to that observed in direct eye trauma. The critical pressure values causing aqueous humor leak and/or keratoprosthesis extrusion were compared to those found to blow up unoperated eyes. No statistical difference was found between operated and control eyes (6 pairs of eyes). This KPro type showed its efficacy for keratoprosthesis fixation.