Xiaoxu Zhou

Video microscope recording of the dynamic course of thrombosis and thrombolysis of the retinal vein in rabbits.

Purpose:The purpose of this study was to investigate the dynamic course of experimental thrombosis and thrombolysis of the retinal veins. Methods:Dynamic changes in the blood flow in the retinal veins were documented on a digital recorder through a microscope-mounted video camera and were analyzed on a monitor by video playback. Photochemical thrombus formation was induced by intravenous injection of 30% Rose Bengal followed by endoillumination of individual branch retinal veins of the eyes of 20 anesthetized pigmented rabbits. Subsequently, 10 rabbits were treated with an infusion in an ear vein of 3 mg/kg recombinant tissue plasminogen activator, whereas 10 control rabbits were administered with similar volumes of normal saline solution. Occlusion and recanalization were confirmed histologically and assessed by video microscopy. Results:At the site exposed to light, photochemical injury resulted in the formation of a white thrombus, stagnation of blood flow, and subsequent complete venous occlusion in 20 rabbits. In this study, of the 10 animals in the recombinant tissue plasminogen activator treatment group, 9 (90%) showed evident thrombolysis, whereas none of the control group animals showed evident thrombolysis. The video showed that the massive thrombus disrupted into nonuniform fragments, which were quickly washed away by the blood flow, and the circulation was reestablished with no recurrence of secondary obstruction. Conclusion:In vivo data suggest that video microscopy may provide a visual approach for observing the dynamic changes occurring during experimental thrombus formation and lysis by the early administration of recombinant tissue plasminogen activator; this approach may assist in future investigation of thrombus research of ocular fundus.

Angiography reveals early hiding iris neovascularization after ischemic CRVO.

1 Tianjin Medical University Eye Hospital, Tianjin 300384, China 2 Department of Electron Microscope, Tianjin Medical University Basic Medical College, Tianjin 300070, China Co-first authors: Zhi-Qing Li and Xiao-Xu Zhou Correspondence to: Jian-Guo Wu. Tianjin Medical University Eye Hospital, No. 251 Fukang Road, Nankai District, Tianjin 300384, China. wujg204329@sina.com Received: 2012-04-17 Accepted: 2013-03-20

A Simultaneous Iris Angiography Technique in Pigmented Rabbits

Purpose: To report a simultaneous iris angiography (IA) technique combined with the use of indocyanine green (ICG) and fluorescein sodium (FS) in pigmented rabbits. Methods: 15 rabbits were randomly divided into 3 groups according to the dye doses: the dose of the lower-volume group was 2 mg FS and 2 mg ICG; the dose of the moderate-volume group was 5 mg FS and 5 mg ICG, and the dose of the higher-volume group was 8 mg FS and 8 mg ICG. Fifteen IAs were performed by a confocal scanning laser ophthalmoscope and a rapid localization technique giving a flat-on image. Results: Simultaneous digital angiography provided two kinds of a fully dynamic video of iris vessels fluorescein in all pigmented rabbits, which is the same in pigmented and albino rabbits and no vascular pattern was hidden by the iris stromal pigment. Furthermore, dye doses influenced the IA effect in rabbits. The lower-volume dye can demonstrate iris vessels, without obvious leakage, which, however, extinguish rapidly after 10–15 s. In the higher-volume group, vascular imaging lasted longer, but subsequently significant FS and ICG leakage appeared as streams on the surface of the iris until the dye disappeared from the iris vessels; the diffuse and intense aqueous fluid lasted 1 day. The moderate-volume dye displayed vessels clearly by ICG for 300 s, without leakage; FS clear vessels were maintained for about 15–20 s and the structure of the iris became fuzzy due to quick leakage. Conclusions: Simultaneous IA with a rapid localization technique allows high-quality imaging of the pigmented rabbits and the moderate dosage of 5 mg FS and 5 mg ICG is preferred for best visualization.

Comparison of disposable sutureless silicone ring and traditional metal ring in 23-gauge vitrectomy combined with cataract surgery

Background: The purpose of this prospective, interventional, comparative case series was to evaluate the efficiency and feasibility of a disposable sutureless silicone lens ring for corneal contact lens stabilization during combined 23-gauge vitrectomy and cataract surgery. Methods: We developed a ring consisting of a single silicone component with three footplates along the ring margin to fit cannulae for holding conventional contact lenses. Thirty eyes from 30 patients with cataract and vitreoretinal disease were included, and divided into two matched groups according to disease type and ring used. In Group A, we used a 23-gauge transconjunctival vitrectomy system and a disposable sutureless silicone lens ring (n = 15). In Group B, we used a 23-gauge transconjunctival vitrectomy system and a conventional metal lens ring (n = 15). The main outcome measures were: time required for vitrectomy preparation, rate of intraoperative corneal limbus bleeding, and limbus scar rate at the final follow-up visit. Results: Thirty cases were successfully completed. The average vitrectomy preparation time was less in Group A than in Group B (P < 0.01), and the average preparation time saved was 3.94 minutes. None of the Group A patients had intraoperative bleeding or postoperative scarring, whereas all 15 Group B cases had bleeding and five had scarring. There was a statistically significant difference between Group A and Group B for these complications (P ≤ 0.05). Conclusion: This report demonstrates the advantages of using a sutureless silicone ring during combined 23-gauge vitrectomy and cataract surgery. Using this method could allow extra time for the surgeon to pay more attention to complex vitreoretinal procedures.

Disposable sutureless silicone contact lens ring for use with a self-sealing cannula system during vitrectomy.

The use of corneal contact lenses during vitrectomy has become indispensable because they offer an excellent view of the fundus. In traditionally used systems, the lenses were supported by a sutured ring with either two or four sutures.1 However, the placement of these sutures is time-consuming, has the potential to cause bleeding, and increases the possibility of globe perforation. The concept of a suture-free lens ring was first introduced by Ikuno et al.2 They also designed a system, which comprises a stainless steel ring that has 2 upright tabs (180° apart) with a hook on the top and 2 elastic silicone bands (8 mm in diameter) to fix the ring to the eyelid speculum. Although this system was an improvement in comparison to suturing, the silicone bands hindered the rotation of the globe and scleral depression. Chalam et al3–7 designed a series of suture-free lens systems, including three aspheric plastic lenses, a standard wide-angle contact lens, and four footplates. However, these systems were easily displaced from the visual axis when the eyeball was tilted or when they came into contact with the lid margin or lid speculum. On the basis of the self-sealing cannula system, Chong et al8 developed a system consisting of a single plastic ring with multiple concavities at the ring margin to fit 25-gauge cannulas. This ring provided considerable stability to the contact lens system without obstructing the surgeon’s visual field even while using a top-heavy panoramic contact lens or when scleral depression was used for vitreous-based dissection. However, we have noted that the use of 23-gauge cannulas is more popular at present. Therefore, we designed a flexible, disposable suture-free silicone ring to be used in conjunction with the advanced 25-, 23-, and recent 20-gauge self-sealing cannula systems9 and combined surgeries such as vitrectomy and phacoemulsification.