Post-vitrectomy tissue plasminogen activator injection for central retinal vein occlusion.

Three patients with recent central retinal vein occlusion underwent vitrectomy, fluid-air exchange, and a 50-microg tissue plasminogen activator intravitreal injection. After a mean follow-up period of 38.7 weeks, no patient's vision improved and one patient required an additional vitrectomy. Post-vitrectomy tissue plasminogen activator injection did not improve the course of central retinal vein occlusion in these three cases.

The role of vitrectomy assisted rt-PA injection for the management of branch retinal vein occlusion: case report.

Case reports on three patients who underwent vitrectomy assisted t-PA injection for the management of branch retinal vein occlusion. Three-port, 20-gauge vitrectomy was performed under local anesthesia. After posterior vitreous detachment and fluid-air exchange, 50 microg t-PA/0.5 ml were injected in the eye. All patients were instructed for strict supine position for 6 hours. Main outcome measure was visual acuity. Three patients with branch vein occlusion (BVO) were studied, with duration of symptoms less than 25 days, and mean follow-up period of 18.8 months. Although no intraoperative complications were noticed, no one showed any significant improvement of vision. One patient required a second operation for the management of intravitreal hemorrhage, and another developed an epiretinal membrane. Vitrectomy assisted t-PA injection does not seem to improve the course of branch retinal vein occlusion in this small case series. Future research on intravitreal thrombolysis needs to be focused on additional mechanical approaches and modalities that can facilitate the access of the drug into the vascular lumen.

Spontaneous closure of macular holes developed after pars plana vitrectomy.

PURPOSE: To report a small, retrospective, noncomparative case series (3 patients) of idiopathic macular holes with spontaneous closure in previously vitrectomized eyes. METHODS: The first patient developed a macular hole 14 months after vitrectomy for penetrating ocular trauma. In the rest of the patients, the macular holes were documented ten days and two months after vitrectomies for retinal detachment. RESULTS: In all cases the macular holes resolved spontaneously 2 years, 6 and 9 months after their documentation, respectively. CONCLUSIONS: Despite the limitations placed by the small sample of studied patients, it seems that spontaneous closure of macular holes developed after vitrectomy can happen as part of their natural course. Both pathogenetic and repair factors involved in macular hole can act spontaneously in a vitrectomized eye.

Stability of protein-encapsulating DRV liposomes after freeze-drying: A study with BSA and t-PA.

Stability of protein-encapsulating DRV (dried-rehydrated vesicle) liposomes is evaluated after freeze-drying vesicles in presence (or not) of trehalose. Two proteins, bovine serum albumin (BSA) and tissue-type plasminogen activator (t-PA), are used, and protein-encapsulating liposomes with different lipid compositions are prepared by DRV technique. Encapsulation efficiencies are calculated, after measuring BSA with a fluorescence technique and t-PA's amidolytic activity toward a chromogenic substrate. Experimental results show that encapsulation of BSA in vesicles ranges between 35 and 53% of the protein and is only slightly affected by lipid composition. For t-PA, entrapment efficiencies are lower, ranging between 2 and 16%, while lipid composition has substantial effect on entrapment (cholesterol inclusion is very important). After freeze-drying, some lipid compositions remain stable, retaining most of initially entrapped proteins, while others do not, but they may be stabilized by trehalose. In the case of BSA, liposome behavior cannot be explained based on lipid membrane rigidity (more rigid = more stable). This may be connected with previously demonstrated interactions of BSA with membranes. Oppositely, t-PA behavior is more predictable, meaning that the lipid composition selected for the specific therapeutic application determines the need for cryoprotectant addition before freeze-drying t-PA containing DRV liposomes, perhaps due to the fact that under conditions applying minimum or no interactions between t-PA and lipid membranes occur.Thereby, interactions between proteins and membranes determine not only the encapsulation efficiency but also the need for cryopreservation of liposomal protein formulations.

Study of conjunctival goblet cell morphology and tear film stability in pseudoexfoliation syndrome.

BACKGROUND: Tear secretion and tear film stability seem to be influenced by pseudoexfoliation syndrome (PEX). Histopathological evaluation of conjunctival goblet cells in PEX patients might explain the influence on tear film stability. METHODS: In a prospective, cross-sectional study, 40 eyes of 40 patients with PEX (study group) had measurement of Schirmer test with anesthesia and break-up time prior to cataract surgery. At the end of an uneventful operation, a 1 x 1.5 mm sample of conjunctival tissue was obtained and light and electron microscopy were performed. Results were compared with a control group. Histology evaluation was masked. Primary outcome measures included Schirmer test with anesthesia, break-up time, goblet cell density and morphological character of conjunctiva and conjunctival goblet cells. RESULTS: Both Schirmer test and break-up time values were significantly lower (P= 0.01 and P= 0.001) in the PEX patients (mean 10.6 mm and 8.6 s respectively) than in the control group (13.4 mm and 12.3 s respectively). The number of goblet cells in patients with PEX compared with the control group showed no statistically significant difference (P= 0.66). Use of trichrome stain revealed significant differences in the staining properties of goblet cells between patients with PEX and controls. On electron microscopy, typical pseudoexfoliation filaments were found in the connective tissue of conjunctiva of PEX patients. Remarkable changes of mucin pockets in the study group were also noticed; they had extremely irregular distribution, various forms of size and appearance and even complete collapse. CONCLUSION: Pseudoexfoliation seems to alter basic features of goblet cell morphology, thus affecting tear film stability. Further studies are necessary to determine the exact mechanism.

Erbium:YAG laser deep sclerectomy: an alternative approach to glaucoma surgery.

BACKGROUND AND OBJECTIVES: To study and evaluate, prospectively, the effectiveness and the safety of deep sclerectomy when it is performed with the assistance of the erbium:YAG laser in eyes with primary open-angle glaucoma. PATIENTS AND METHODS: Forty eyes of 40 patients with primary open-angle glaucoma or pseudoexfoliative glaucoma were enrolled consecutively to undergo laser deep sclerectomy. Mitomycin C (0.2 mg/mL for 2.5 minutes) was also used before the superficial scleral flap formation. The follow-up was 24 months for all patients. RESULTS: The intraocular pressure was significantly decreased by 9.15 mm Hg or 35.1% (from 26.05 +/- 2.55 to 16.9 +/- 3.45 mm Hg) at the end of the follow-up period. The complete and qualified success rates at the end of the follow-up period were 37.5% and 62.5%, respectively. Mild complications such as choroidal detachment, hyphema, and leakage were observed. CONCLUSIONS: The use of the erbium:YAG laser for performing a deep sclerectomy procedure seems to be a safe and relatively effective alternative to the conventional surgical procedure. Further studies and longer follow-up are necessary for the evaluation of the efficacy of this technique.

Primary deep sclerectomy versus primary deep sclerectomy with the use of mitomycin C in primary open-angle glaucoma.

PURPOSE: To prospectively study and compare the effectiveness and the safety of primary deep sclerectomy with and without the use of mitomycin C in eyes with open-angle glaucoma. PATIENTS AND METHODS: A total of 90 eyes of 90 patients with primary open-angle glaucoma or pseudoexfoliative glaucoma underwent deep sclerectomy. Patients were enrolled consecutively and assigned randomly to undergo deep sclerectomy without the use of mitomycin C (DS group) and deep sclerectomy with the application of mitomycin C (DSMMC group) in a concentration of 0.2 mg/mL for 2.5 minutes, before the superficial scleral flap formation. RESULTS: The intraocular pressure was significantly decreased by 7.13 mm Hg or 27.59% in the DS group and by 11.68 mm Hg or 42.25% in the DSMMC group at the end of the follow-up period. The intraocular pressure reduction in the DSMMC group was statistically significant when compared with that in the DS group (P <0.05). The complete (IOP <22 mm Hg without medication) and qualified (IOP < 22 mm Hg with or without medication) success rates at the end of the follow-up period were 42.5% and 72.5% in the DS group and 50% and 95% in the DSMMC group. The qualified success rate in the DSMMC group was statistically significant when compared with that in the DS group. Differences in complications (choroidal detachment, hyphema, leakage) seen between the two groups were statistically nonsignificant. A hemorrhagic detachment of the Descemet membrane was observed in one eye in the DSMMC group. CONCLUSIONS: The use of intraoperative mitomycin C during deep sclerectomy significantly reduced the postoperative IOP and increased the success rate of the procedure.