relation between oxygen saturation level and retionopathy of prematurity

Introduction: Oxygen therapy used for preterm infant disease might be associated with oxygen toxicity or oxidative stress. The exact oxygen concentration to control and maintain the arterial oxygen saturation balance is not certainly clear. We aimed to compare the efficacy of higher or lower oxygen saturations on the development of severe retinopathy of prematurity which is a major cause of blindness in preterm neonates

Methods: PubMed was searched for obtaining the relevant articles. A total of seven articles were included after studying the titles, abstracts, and the full text of retrieved articles at initial search. Inclusion criteria were all the English language human clinical randomized controlled trials with no time limitation, which studied the efficacy of low versus high oxygen saturation measured by pulse oximetry in preterm infants

Result: It can be suggested that lower limits of oxygen saturations have higher efficacy at postmesetural age of

Discussion: Applying higher concentrations of oxygen supplementations at mesentural age >/=32 weeks reduced the development of retinopathy of prematurity. Lower concentrations of oxygen saturation decreased the incidence and the development of retinopathy of prematurity in preterm neonates while applied soon after the birth

Conclusions: Targeting levels of oxygen saturation in the low or high range should be performed cautiously with attention to the postmesentural age in preterm infants at the time of starting the procedures

Effects of intravitreal bevacizumab injection on the clinical manifestations of nonproliferative diabetic retinopathy in patients with macular edema: a systematic review

Introduction: Bevacizumab [Avastin] is considered as an effective strategy in the treatment of various ocular diseases. As a vascular endothelial growth factor [VEGF] inhibitor, Avastin is used to control macular edema in patients with nonproliferative diabetic retinopathy [NPDR]. Therefore, in this study, we systematically reviewed the effects of intravitreal bevacizumab injections on nonproliferative stage of diabetic retinopathy

Methods: Scopus and PubMed were systematically searched to find articles in which the effect of Avastin [bevacizumab] had been evaluated in nonproliferative stage of diabetic retinopathy. Literature search was performed using "Avastin OR bevacizumab", "nonproliferative stage" and "diabetic retinopathy" as keyterms in the title, keywords, and abstract

Result: All 47 articles were found in all databases, two additional records were found through reference list screening, and only 10 articles were relevant to the purpose of this study. According to the inclusion/exclusion criteria, 39 articles were excluded in several step processes of article selection. The results revealed that intravitreal injection of bevacizumab could be safely used to treat various ocular disease, particularly NPDR stage of diabetic retinopathy with macular edema

Discussion: Bevacizumab is considered as a novel and effective modality in the treatment of various ocular diseases such as retinal neovascularization, neovascular glaucoma, macular edema, and other ocular complications. Findings also suggested that bevacizumab is a suitable therapeutic approach in clinical use

Conclusion: According to the results of included documents, intravitreal injection of bevacizumab could be considered as a promising treatment modality in the clinical management of NPDR stage of diabetic retinopathy

Nicotinic acid treatment for retinal vein occlusion

To evaluate the effect of nicotinic acid in management of retinal vein occlusions [CRVO or BRVO]. This prospective nonrandomized pilot study included 20 patients [21 eyes] with CRVO or BRVO that received nicotinic acid [3 g/day] for 3 months. A complete ophthalmologic examination uncorrected visual acuity [UCVA], best spectacle-corrected visual acuity [BSCVA], testing for a relative afferent pupillary defect [RAPD], slit-lamp examination, gonioscopy, intraocular pressure [IOP] measurement, fundoscopy and fundus photography was performed. Four patients did not appear for follow-up and hypersensitivity reaction to nicotinic acid and severe hyperglycemia happened in two patients. Therefore, the results of treatment in 16 eyes of 15 are reported. These patients had a mean age of 59.56 +/- 11.12 years. The average length of follow-up was 8.6 +/- 2.7 months. The mean BSCVA was 1.56 +/- 0.66 before treatment, 1.38 +/- 0.72 [p>0.05] at one month and 0.88 +/- 0.69 [p<0.01] at three months. The last BSCVA of all 16 eyes averaged 0.97 +/- 0.73 [p<0.01]. All patients had reduction of hemorrhagic events, cotton wool spots, edema in macula and disc, venous tortuosity, and dilation on basis of fundus photographs 3 months after treatment. Nicotinic acid usage provides enough time for development of collateral vessels, by induction of vasodilatation. Nicotinic acid use is tolerable and is related with mild systemic side effects.

Evaluation of cyclosporine A eye absorption after administration of liposomal or conventional forms in animal model

A lot of researches have investigated the effects of topical cyclosporine A on the eye surface layers' diseases. By now the main limitation in cyclosporine application is the low permeation of the drug into the posterior segments of the eye. The aim of present study was to formulate high permeable dosage form can be beneficial in the topical treatment of the uveitis. To reach higher corneal drug absorption and drug concentration in the posterior segments of the eye, 3 nanoliposomal formulations containing 0.5 mg/ml cyclosporine A were prepared. Liposomal formulations and the commercial product [Restasis] were instilled in the right and left eyes of the rabbits, respectively. The rabbits were killed in the 3, 7, 14 and 28 days of study and the aqueous humor and vitreous were extracted. Mean size of liposomal formulation number 1, number 2 and number 3 were 107.2 +/- 0.7, 129.3 +/- 0.9 and 144.8 +/- 1.8 nm and their zeta potential were -5.0 +/- 1.7, -5.5 +/- 2.3 and 44.6 +/- 6.2 mV, respectively. Results of ocular analysis showed that the liposomal formulations could increase the concentration of the drug in the aqueous and vitreous like Restasis. But, in contrast with what has been expected the findings of this study implicate nanoliposomal formulations prepared could not make a significant difference in concentration of the drug in aqueous and vitreous humor compared to Restasis [anionic microemulsion]. In conclusion, we can state that liposomes with the same composition as our formulations are not more efficient than microemulsion for cyclosporine as ophthalmic drug delivery

Early decomposition of retained heavy silicone oil droplets

Purpose: To report a case of early decomposition of retained heavy silicone oil droplets

Case Report: The single highly myopic eye of a 16-year-old boy with history of scleral buckling and buckle revision developed redetachment due to inferior retinal dialysis. The patient underwent pars plana vitrectomy and injection of heavy silicone oil. Early emulsification of the silicone oil was observed following surgery, which was removed 4 weeks later in another operation. Retained heavy silicone droplets lost their heavier-than-water specific gravity within 2 months together with extensive iris depigmentation, and release of pigment granules into the anterior chamber and vitreous cavity

Conclusion: This case report demonstrates that heavy silicone oil droplets can undergo in vivo chemical decomposition with possible toxic effects on ocular tissues

simple way to clear the media for vitrectomy in eyes with corneal edema

Herein we introduce a simple approach for clearing an edematous cornea during vitreoretinal surgery in eyes with decompensated corneal endothelium, allowing the surgeon to postpone penetrating keratoplasty. This technique was performed in 3 eyes by filling the anterior chambers with air or silicone oil, and sufficiently cleared the media for completion of vitrectomy. This simple technique enables completion of the vitrectomy without a temporary keratoprosthesis and penetrating keratoplasty in eyes with corneal edema due to endothelial decompensation

Foveal protection with viscoelastic material during removal of posterior segment foreign bodies

Foreign bodies may drop during removal from the posterior segment and result in foveal damage. Due to high specific gravity and viscosity, ophthalmic viscosurgical devices [OVDs] can dampen and redirect the force of the dropping foreign body and therefore protect the fovea. Herein we describe our technique of foveal protection with OVDs and briefly demonstrate the results in five eyes with large posterior segment foreign bodies

Anatomical and visual outcomes of three different scleral buckling techniques

To compare the anatomical and visual outcomes of three different scleral buckling techniques and to explore the effect of cryotherapy and subretinal fluid drainage [SRFD] on outcomes of surgery. This retrospective study was performed on 111 eyes of 109 patients undergoing scleral buckling for rhegmatogenous retinal detachments [RRDs] by a single surgeon. Pre-, intra- and postoperative data were retrieved from hospital records. Buckles were radial in 27 [24.3%], circumferential [segmental] in 16 [14.4%] and encircling in 68 [61.3%] eyes. Anatomical and visual results were comparable with all three buckling techniques. Application of cryotherapy, the spot number, and SRFD did not affect anatomical and visual results. The only preoperative factor associated with poorer anatomical results was the presence of multiple retinal breaks [P=0.006]. The following preoperative factors affected visual outcomes on univariate analysis: extent of retinal detachment [r=0.417, P=0.011] and relative afferent pupillary defect [r=0.423, P=0.02]. Preoperative macular status [attached vs detached] also had a significant effect on visual outcomes [P < 0.001]. Based on multivariate analysis however, only preoperative macular status was significantly correlated with visual results [P=0.022]. Silicone sponges placed for non-encircling surgery were removed due to ocular dysmotility in 4 [3.6%] eyes, cosmetic reasons in 3 [2.7%] cases and extrusion in 2 [1.8%] eyes. One encircling tire was also removed due to extrusion. Surgical technique and performing cryotherapy or SRFD do not seem to influence the anatomical and visual outcomes of scleral buckling. Postoperative complications seem to be more prevalent with non-encircling techniques

Alteration of tear film after vitrectomy and its influencing factors

To detect the prevalence of dry eye after vitrectomy and its influencing factors. Schirmer I, Tear Basic Secretion Test and Tear Breakup Time was done preoperatively and 3 months postoperatively on consecutive patients undergoing vitrectomy in Khatam Hospital from 2005 to 2006. Eyes with previous peritomies of more than 120° and symptoms of dry eye or tear tests compatible with a diagnosis of dry eye were excluded. Intraoperative factors including the extent of peritomy, extent of inadvertent conjunctival lacerations, extent of scleral depression and the instrument used for scleral depression were recorded. Scleral depression was graded extensive if it was done for more than 180° of globe circumference. Seventy five eyes of 75 patients were studied. Forty six [61.3%] of patients were male. The mean age of the patients was 47.13 +/- 18.85 years. Peritomy size was on average 179.33 +/- 124.75 and the mean size of conjunctival ruptures was 2.18 +/- 4.33 mm. Based on the type of instrument used for scleral depression, patients were divided into 4 groups: 1] metallic instrument, 6 cases [8%] 2] cotton applicator 32 cases [42.7%] 3] both, 14 cases [18.8%] 4] none [no scieral depression], 23 cases [30.7%]. Of 52 cases with scleral depression, the depression was extensive in 35 cases [46.7% of all eyes]. Thirteen eyes [17.3%] developed tear film parameters or symptoms consistent with dry eye. All of these eyes had undergone extensive scleral depression. Cotton applicator had been used significantly more in cases which developed dry eye. There was a direct relation between extent of peritomy and inadvertent conjunctival laceration and development of dry eye. Due to damage to the conjunctiva during operation, vitrectomy is apt to cause dry eye. To lower the risk of this complication, scleral depression, peritomy and possibility of inadvertent conjunctival lacerations should be minimized. It is also better to use metallic instruments for scleral depression rather than cotton applicator

Silicone oil removal from aphakic eyes using a side irrigating cannula

In an interventional case series, 11 aphakic eyes of 11 patients with previous vitrectomy and silicone oil tamponade underwent passive silicone oil removal under topical anesthesia through a single clear cornea incision with use of a side irrigating phacoemulsification irrigation cannula without performing a sclerotomy. All procedures were simple, short and uncomplicated. The only observed complication was minimal localized corneal edema the day after the procedure, which resolved within 1-2 days. Use of a side irrigating cannula permits safe and simple removal of silicone oil under topical anesthesia through a single clear cornea incision without need for sclerotomy