ABSTRACT
The vitreoretinal interface is involved in a wide range of vitreoretinal disorders and separation of the posterior vitreous face from the retinal surface is an essential part of vitrectomy surgeries. A diverse range of enzymatic and non-enzymatic agents are being studied as an adjunct before or during vitrectomy to facilitate the induction of posterior vitreous detachment. There is a significant body of knowledge in the literature about different vitreolytic agents under investigation for a variety of pathologies involving the vitreoretinal interface which will be summarized in this review. Articles retrieved by Pubmed search using keywords "Vitreolysis", pharmacologic Vitreolysis, plasmin and vitrectomy, and microplasmin and vitrectomy, were used in this review. recent reports have raised strong hopes that pharmacologic vitreolysis may eventually find its way to clinical practice. Further investigations will demonstrate whether enzymatic vitreolysis could be used as an adjunct and/or alternative treatment for treatment of vitreoretinal disorders
ABSTRACT
To compare ophthalmic artery velocity in eyes with nonarteritic anterior ischemic optic neuropathy [NAION] with that of normal fellow eyes. In this case-control study, 20 patients with unilateral NAION and disease onset less than 8 weeks, were enrolled. Using color Doppler imaging, mean, maximum systolic and end diastolic ophthalmic artery velocities were evaluated. The results were compared between the fellow eyes. Twelve men and 8 women with a mean age of 54.6 +/- 11.8 years were included. Mean interval between disease onset and velocity measurements was 27.5 +/- 12.8 days. Mean [18.5 +/- 0.8 vs 19.9 +/- 2.8], maximum systolic [37.9 +/- 4.09 vs 39.7 +/- 3.1] and end diastolic [10.3 +/- 2.1 vs 12.3 +/- 2.5] ophthalmic artery velocities in NAION eyes were significantly less than that of the normal fellow eyes [P=0.01, P=0.001 and P<0.001, respectively]. No significant difference was found in subgroup analysis of patients with and without diabetes, and with and without systemic hypertension. NAION seems to be associated with changes in ophthalmic artery velocity
ABSTRACT
To evaluate the safety of different doses of intravitreal bevacizumab in rabbit eyes. Twelve eyes of 6 rabbits underwent intravitreal injection of 5, 7.5 and 10 mg of bevacizumab. In each rabbit, one eye was considered for bevacizumab injection and the fellow eye served for either placebo injection or observation. All eyes were examined before and I, 2, 3, 7, 14 and 28 days after intravitreal injections. Electroretinography [ERG] was performed before and 14 days after the injections. 28 days after the injections, all eyes were enucleated and examined with light and electron microscopy. In the clinical examination, significant vitritis was observed in one of the 10 mg injected eyes from first post-injection which was eliminated by the 7th day. Cataract was seen in the same eye. Post-injection ERGs showed no significant changes. Increase in Muller-like cells was observed in the histological examination in the injected eyes. Intravitreal injection of 5 and 7.5 mg doses of bevacizumab was safe in rabbit eyes; however, the 10 mg dose was associated with intraocular inflammation
ABSTRACT
Age related macular degeneration [AMD] is the most common cause of visual impairment in the population above 64 years of age in developed countries. Most cases of severe vision loss due to AMD are caused by exudative changes in the macula. Extensive research on AMD has led to advances in its prophylaxis and treatment in recent years. Photodynamic therapy [PDT] was developed in late 1990's in which free oxygen radicals damage the neovascular tissue in a non-thermal way. The first prophylactic treatment for AMD was approved in 2001 which includes oral administration of a combination of vitamins, antioxidants, and minerals. It was shown that this treatment decreases the chance of progression of dry type AMD to more advanced atrophy and choroidal neovascularization. Laser treatment for drusen is currently under investigation. Vitrectomy for removal of subretinal choroidal neovascularization [CNV] has proven not to be effective for visual improvement. Translocation of fovea to an area away from CNV has met some success but the chance of loss of peripheral vision has hampered its general acceptance. An important area of research is the pharmacologic approach to counteract choroidal neovascularization. Three groups of anti-angiogenic agents have been studied; 1] anti-VEGF [vascular endothelial growth factor], 2] recombinant anti-VEGF antibodies, and 3] steroids. Transpupillary thermotherapy has been used for several years and was claimed to be effective for treatment of CNV in some small uncontrolled studies but failed to be more effective than sham treatment in a recent multicenter controlled trial. In general, it seems that the most promising areas of research in the treatment of AMD are prophylactic treatment and antiangiogenic therapy
ABSTRACT
Purpose: to evaluate the results of trans-scleral diode laser retinopexy for induction of chorioretinal reaction in scleral buckling surgery
Methods: this before-after clinical trial was performed on 69 eyes of 66 patients with rhegmatogenous retinal detachment eligible for scleral buckling
Results: the retina was reattached with scleral buckling in 64 eyes [92.8%]. In 4 eyes, the scleral buckling was performed twice [modified]. In 5 eyes, significant PVR developed post-operatively [7.2%], two of which had pre-operative PVR grade B. In two eyes, retinal photocoagulation was performed through silicon implants and sclera. Best corrected visual acuity [Log MAR] was 1.22 +/- 1.5 preoperatively and 0.74 +/- 1.75 postoperatively [P<0.02]. In 95% of the eyes with reattached retina [61 eyes], visual acuity improved or remained stable. In 12 eyes, rupture of Bruch's membrane associated with retinal break formation happended which did not affect retinal reattachment. No other complications were seen which could be ascribed to diode retinopexy
Conclusion: trans-scleral diode laser photocoagulation for induction of chorioretinal reaction in scleral buckling is a safe and effective procedure. The ability to perform retinopexy through episcleral silicon implants is a definite advantage of this method over cryopexy