Major challenges in vitreoretinal surgery

Silicone oil as a corneal lubricant to reduce corneal edema and improve visualization during vitrectomy

AIM

To evaluate the efficacy and safety of silicone oil (SO) as a corneal lubricant to improve visualization during vitrectomy.

METHODS

Patients who underwent vitreoretinal surgery were divided into two groups. Group 1 was operated on with initial SO (Oxane 5700) as a corneal lubricant. Group 2 was operated on with initial lactated ringer's solution (LRS) and then replaced with SO as required. Fundus clarity was scored during the surgery. Fluorescein staining was performed to determine the damage to corneal epithelium.

RESULTS

Totally 114 eyes of 114 patients were included. Single SO use maintained a clear cornea and provided excellent visualization of surgical image. In group 1, the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes. In group 2, corneal edema frequently occurred after initial LRS use. The fundus clarity was grade 3 in 19/69 eyes, 2 in 37/69 eyes and 1 in 13/69 eyes (P<0.05). SO was applied in 29 eyes of initial LRS use with subsequent corneal edema, which eliminated the corneal edema in 26 eyes. Corneal fluorescein staining score in group 1 was 0 in 28 eyes, 1 in 11 eyes and 2 in 6 eyes, and 40, 20 and 9, respectively, in group 2 (all P>0.05).

CONCLUSION

The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.

TRANSSCLERAL INCISION FOR PEELING SUBRETINAL PROLIFERATION TISSUE IN GRADE C PROLIFERATIVE VITREORETINOPATHY

PURPOSE

The purpose of this study was to investigate the clinical outcomes of an optimized method to clearly remove the subretinal proliferative tissue by transscleral puncture into the subretinal space in patients with grade C proliferative vitreoretinopathy without inducing retinal injury.

METHODS

This was a prospective clinical observation study. Eight consecutive patients who had undergone optimized vitrectomy surgery for retinal detachment complicated by grade C proliferative vitreoretinopathy were investigated. Subretinal proliferation was cleared by adding one additional scleral 23-gauge trocar under the detached retina at 9 mm to 10 mm from the limbus. After the sclera is pierced, the puncture knife changed its direction without touching the retina. 23-G intraocular forceps were used to remove the proliferation strand or membrane through the puncture channel.

RESULTS

Retinal reattachment was achieved in each case without a retinotomy. The mean best-corrected visual acuity was improved within the first 1 month ( P = 0.039) and remained stable at the following phase. There were no postoperative complications, such as reoccurrence of retinal detachment or proliferative vitreoretinopathy. No postoperative hemorrhage or hypotension was observed.

CONCLUSION

The satisfying results demonstrated the feasibility of this cost-effective, easy-to-follow, transscleral vitrectomy method in treating retinal detachment with grade C proliferative vitreoretinopathy.

Vitrectomy without encircling band for rhegmatogenous retinal detachment with inferior break utilizing 3D heads up viewing system

Purpose:

This study aimed to determine the anatomical and functional outcomes of pars plana vitrectomy without encircling band for primary rhegmatogenous retinal detachments with inferior breaks utilizing 3D heads up viewing system.

Method:

This prospective, single-center study included 22 consecutive eyes with primary rhegmatogenous retinal detachments with only inferior breaks with proliferative vitreoretinopathy (PVR) CP2 or less, who underwent pars plana vitrectomy without encircling band, with silicon oil as tamponade. All surgeries were performed by a single surgeon. The single operation success rate was recorded after silicon oil removal.

Results:

The patient population consisted of 08 women (36%) and 14 men (64%) with a mean age of 56.6 +/− 14.7 years. The mean follow-up period was 8 months. A single break was present in 13 cases (59%), and 2–4 breaks were present in 9 cases (40.9%). The mean time for the surgical procedure was 35 min (range: 25–50). The macula was found to be detached in 19 cases (86.36%) and attached in 3 cases (13.6%). Single operation success rate (SOSR) of vitrectomy, after silicon oil removal without encircling band, for primary rhegmatogenous retinal detachment (RRD) with inferior breaks was 95.4%. One case redetached due to PVR changes and underwent re-surgery. Final reattachment was achieved in all 22 cases (100%). Mean best-corrected visual acuity (BCVA) significantly improved from 1.43 ± 0.59 logarithm of the minimum angle of resolution (logMAR) to postoperative BCVA was 0.48 ± 0.34 logMAR (P = 0.001).

Conclusion:

Pars plana vitrectomy without encircling band, utilizing 3D heads up the system in RRDs with inferior breaks in eyes with PVR grade C2 or less, provides good outcome.

PRODUCTION AND APPLICATION OF ANGIOSTATINS FOR THE TREATMENT OF OCULAR NEOVASCULAR DISEASES

Angiostatins comprise a group of kringle-containing proteolytically-derived fragments of plasminogen/plasmin, which act as potent inhibitory mediators of endothelial cells proliferation and migration. Angiostatins are involved in modulation of vessel growth in healthy tissues and various pathological conditions associated with aberrant neovascularization. The aim of the present paper was to summarize available information, including our own experimental data, on prospects of angiostatin application for treatment of ocular neovascular diseases (OND), focusing on retinal pathologies and corneal injury. In particular, literature data on prospective and retrospective studies, clinical trials and animal models relating to the pathophysiology, investigation and management of OND are described. Special emphasis was made on the laboratory approaches of production of different angiostatin isoforms, as well as comparison of antiangiogenic capacities of native and recombinant angiostatin polypeptides. Several studies reported that angiostatins may completely abolish pathologic angiogenesis in diabetic proliferative retinopathy without affecting normal retinal vessel development and without exhibiting adverse side effects. Angiostatins have been tested as a tool for corneal antiangiogenesis target therapy in order to manage diverse ocular surface pathological conditions induced by traumas, chemical burns, previous surgery, chronic contact lens wear, autoimmune diseases, keratitis and viral infections (herpes, COVID-19), corneal graft rejection, etc. Among all known angiostatin species, isolated K5 plasminogen fragment was shown to display the most potent inhibitory activity against proliferation of endothelial cells via triggering multiple signaling pathways, which lead to cell death and resulting angiogenesis suppression. Application of adenoviral genetic construct encoding angiostatin K5 as a promising tool for OND treatment illustrates a vivid example of upcoming revolution in local gene therapy. Further comprehensive studies are necessary to elucidate the clinical potential and optimal regimes of angiostatinbased intervention modalities for treating ocular neovascularization.