Tissue plasminogen activator attenuates outflow facility reduction in mouse model of juvenile open angle glaucoma.

Tissue plasminogen activator (tPA) has been shown to prevent steroid-induced reduction in aqueous humor outflow facility via an upregulation in matrix metalloproteinase (Mmp) expression. The purpose of this study was to determine whether tPA can rescue outflow facility reduction in the Tg-MYOCY437H mouse model, which replicates human juvenile open angle glaucoma. Outflow facility was measured in Tg-MYOCY437H mice following: periocular steroid exposure and intraocular protein treatment with enzymatically active or enzymatically inactive tPA. Effects of tPA on outflow facility were compared to those of animals treated with topical sodium phenylbutarate (PBA), a modulator of endoplasmic reticulum stress. Gene expression of fibrinolytic pathway components (Plat, Plau, and Pai-1) and matrix metalloproteinases (Mmp-2, -9, and -13) was determined in angle ring tissues containing the trabecular meshwork. Tg-MYOCY437H mice did not display further outflow facility reduction following steroid exposure. Enzymatically active and enzymatically inactive tPA were equally effective in attenuating outflow facility reduction in Tg-MYOCY437H mice and caused enhanced expression of matrix metalloproteinases (Mmp-9 and Mmp-13). tPA was equally effective to topical PBA treatment in ameliorating outflow facility reduction in Tg-MYOCY437H mice. Both treatments were associated with an upregulation in Mmp-9 expression while tPA also upregulated Mmp-13 expression. tPA increases the expression of matrix metalloproteinases and may cause extracellular matrix remodeling at the trabecular meshwork, which results in reversal of outflow facility reduction in Tg-MYOCY437H mice.

Simplified technique for lateral canthal tendon canthopexy.

Purpose: Different techniques for lateral canthal suspension have been used in the management of various eyelid malpositions. We describe a simplified technique for lateral canthal suspension and review its outcome along with a review of existing variations. Methods: We conducted a retrospective chart review of 28 eyelids in 22 patients who underwent simplified lateral canthal suspension. Demographics, symptoms at presentation, and associated eyelid malposition were noted. We evaluated the palpebral fissure and margin-reflex distance 2 (MRD2) on the preoperative and final postoperative photographs by using MEEI FACE-gram software. We also reviewed existing literature on different surgical management options for comparison. Results: At three-month postoperative follow-up, presenting symptoms resolved in all cases. The average postoperative decease in palpebral fissure was 0.73 mm (P = 0.018) and the average decrease of the MRD2 was 1.02 mm (P = 0.0003). Recurrence occurred by three months in one eyelid (4%) with ectropion due to moderate eyelid laxity, and this case was managed with tarsal strip procedure. One patient (5%) who had bilateral surgery had asymmetric lower eyelid position and one patient (5%) had persistent edema of the operated eyelid for six months. Conclusion: This simplified canthal suspension is a simple and effective technique that tightens the lateral canthal tendon and improves the lower eyelid position. It can be used in various mild-to-moderate eyelid laxities and has favorable operative characteristics compared with many existing techniques.