Silicone oil insulation effects on flash electroretinogram and visual evoked potential in patients with retinal detachment / Efectos del aislamiento del aceite de silicona sobre el electrorretinograma flash y el potencial evocado visual en pacientes con desprendimiento de retina

Background: Silicone oil is used as endotamponade following vitreoretinal surgery to maintain the retina reattached when indicated. This study investigates the hypothesis that silicone oil causes insulation effects on the retina by affecting its response to light. Methods: Electrophysiological responses to a flash stimulus were recorded using full-field electroretinography (ERG) and visual evoked potentials (VEP). Recordings were performed in 9 patients who underwent surgery for retinal detachment, before (1–2 days) and after (2–3 weeks) silicone oil removal (SOR) in both the study and the control eye. Flash ERG and VEP recordings were performed according to the ISCEV standard protocol. Results: Statistically significant differences were found in the study eye in the amplitudes of the ERG responses and their corresponding ratios, i.e. the amplitude after SOR over the amplitude before SOR, in all conditions tested. No differences were observed in the control eye. The mean ratio of photopic ERG response was 3.4 ± 2.4 for the study and 1.0 ± 0.3 for the control eye (p<0.001). The mean ratio of ERG flicker response was 3.1 ± 2.4 and 1.0 ± 0.3, respectively (p = 0.003). Scotopic flash ERG ratio was 5.0 ± 4.4 for the study and 1.3 ± 0.6 for the control eye (p = 0.012). No differences were observed for the amplitude and latency of flash VEP response after SOR. Conclusions: Silicone oil causes a reduction in flash ERG responses; no effect was found on flash VEP responses. ERGs in eyes filled with silicone oil should not be considered representative of retinal functionality, in contrast to VEPs, which are not affected by silicone oil presence.(AU)

Silicone oil insulation effects on flash electroretinogram and visual evoked potential in patients with retinal detachment.

BACKGROUND: Silicone oil is used as endotamponade following vitreoretinal surgery to maintain the retina reattached when indicated. This study investigates the hypothesis that silicone oil causes insulation effects on the retina by affecting its response to light. METHODS: Electrophysiological responses to a flash stimulus were recorded using full-field electroretinography (ERG) and visual evoked potentials (VEP). Recordings were performed in 9 patients who underwent surgery for retinal detachment, before (1-2 days) and after (2-3 weeks) silicone oil removal (SOR) in both the study and the control eye. Flash ERG and VEP recordings were performed according to the ISCEV standard protocol. RESULTS: Statistically significant differences were found in the study eye in the amplitudes of the ERG responses and their corresponding ratios, i.e. the amplitude after SOR over the amplitude before SOR, in all conditions tested. No differences were observed in the control eye. The mean ratio of photopic ERG response was 3.4 ± 2.4 for the study and 1.0 ± 0.3 for the control eye (p<0.001). The mean ratio of ERG flicker response was 3.1 ± 2.4 and 1.0 ± 0.3, respectively (p = 0.003). Scotopic flash ERG ratio was 5.0 ± 4.4 for the study and 1.3 ± 0.6 for the control eye (p = 0.012). No differences were observed for the amplitude and latency of flash VEP response after SOR. CONCLUSIONS: Silicone oil causes a reduction in flash ERG responses; no effect was found on flash VEP responses. ERGs in eyes filled with silicone oil should not be considered representative of retinal functionality, in contrast to VEPs, which are not affected by silicone oil presence.

Unusual Penetrating Orbital and Globe Injury With a Veterinary Needle.

We present a rare case of a penetrating injury to the globe and orbit by a veterinary needle. The patient underwent globe exploration and retinal detachment repair under general anesthesia after receiving medical treatment for orbital cellulitis. The case was managed by a multidisciplinary team consisting of a pediatric ophthalmologist, an oculoplastic surgeon, and a retina surgeon. The orbital cellulitis resolved gradually, after which the site of globe penetration was found to be self-sealed, and the retinal detachment was repaired. B-scan ultrasonography and magnetic resonance imaging (MRI) were performed to assess the extent of the injury and evaluate the integrity of the globe. Exploration of presumed Self-sealing globe wounds by a needle should be deferred until the treatment of life-threatening complications like orbital cellulitis and optic nerve infiltration is complete. Prompt judicious care was necessary in this case. It is crucial to implement preventive measures to address the risks involved in children manipulating dangerous objects to avoid preventable accidents and mitigate the potential visual outcomes that may arise as a result.

Vitreous Humor Positive for DNA of Human Herpesvirus 7 in Eye With Ocular Toxoplasmosis.

The aim of this article was to report our findings in a case of infectious uveitis in which the DNAs of both Toxoplasma gondii and human herpesvirus 7 (HHV-7) were detected in the vitreous fluid. A 31-year-old Brazilian man was examined in our hospital with a one-month history of blurred vision (20/40) in the right eye. He had been diagnosed with ocular toxoplasmosis of the right eye at nine years of age and has had repeated relapses. Because of the persistent vitreous opacities and refractoriness to acetylspiramycin and betamethasone, pars plana vitrectomy was performed. Multiplex PCR of the vitreous sample demonstrated the DNAs for both T. gondii and HHV-7. Trimethoprim/sulfamethoxazole with prednisone was prescribed. Six months after the beginning of the therapy, a resolution of the retinochoroiditis was found and the vision recovered to 20/25. Two months later, we performed a pars plana vitrectomy for an epiretinal membrane. The DNAs of both T. gondii and HHV-7 were not detected in the vitreous fluid and the epiretinal membrane. After continued treatment, the best-corrected visual acuity (BCVA) in the right eye improved to 20/16 and the metamorphopsia was reduced. It is inferred from this work that HHV-7 reactivation can activate refractory infectious uveitis in patients with chronic ocular toxoplasmosis.

High-speed Beveled Tip Versus Standard Tip Vitrectomy Probe: A Prospective Randomized Clinical Trial.

Purpose: To compare the efficiency of the advanced ultravit beveled vitrector probe (10,000 cuts per minute) to the current standard ultravit highspeed (7500 cuts per minute) vitrector probe. Methods: A prospective, randomized controlled trial was conducted on patients undergoing routine vitrectomy surgery for epiretinal membrane, full-thickness macular hole, and vitreous opacities. Patients were randomly assigned to undergo PPV with the ultravit highspeed probe (Probe 1) or the advanced ultravit beveled probe (Probe 2). The main outcome measure was time to completion of core vitrectomy and vitreous base shave. Results: Forty patients were enrolled in this study, 20 in each cohort. The average time to completion of core vitrectomy was 10.4 +/- 1.8 min in the Probe 1 cohort compared to 9.7 +/- 2 min in the Probe 2 cohort (P = 0.21). The average time to completion of vitreous base shave was 9.6 +/- 2.7 min in the Probe 1 cohort compared to 9.4 +/- 1.8 min in the Probe 2 cohort (P = 0.39). Conclusion: In the current study, the advanced ultravit beveled probe was noninferior to the ultravit highspeed vitrectomy probe when looking at the time to completion of core vitrectomy and vitreous base shave. The increased cut rate did not affect the efficiency of vitreous removal.

When the Party Goes Wrong: A Case Report of Recurrent Valsalva Retinopathy Treated With Pars Plana Vitrectomy.

Valsalva retinopathy is a preretinal hemorrhage caused by a sudden increase in intrathoracic or intra-abdominal pressure, which generally happens after sudden and intense physical effort. This case report describes a case of Valsalva preretinal hemorrhage first treated with laser membranotomy, which subsequently recurred and was retreated with a pars plana vitrectomy. An 18-year-old male was admitted due to complaints of decreased visual acuity in his right eye for three days. He had been practicing strength training in the gymnasium before the complaints started but denied trauma or other precipitating factors. Fundoscopy revealed a central preretinal hemorrhage, and he underwent laser membranotomy, which successfully released the blood from the sub-hyaloid space into the vitreous cavity. However, the following night, he went to a nightclub party and then returned with the same initial symptoms of decreased visual acuity in his right eye. Fundoscopy revealed a relapse of the hemorrhage, which was now too central for membranotomy. He was proposed for a pars plana vitrectomy, with an aspiration of the blood, which was found to be under the inner limiting membrane. The patient achieved complete functional recovery after two weeks, with visual acuities of 20/20 on his right eye. Valsalva retinopathy may be treated with a conservative non-interventional approach, but laser membranotomy and surgery may be beneficial in selected cases, promoting faster visual rehabilitation and avoiding potential long-term toxicity effects of the prolonged presence of preretinal blood. Compliance with the postoperative rest period is essential after a laser membranotomy is performed, and failure to do it may result in the recurrence of the hemorrhage.

Single-cell RNA sequencing: An overview for the ophthalmologist.

Understanding the molecular composition of pathogenic tissues is a critical step in understanding the pathophysiology of disease and designing therapeutics. First described in 2009, single cell RNA sequencing (scRNAseq) is a methodology whereby thousands of cells are simultaneously isolated into individual micro-environments that can be altered experimentally and the genome-wide RNA expression of each cell is captured. It has undergone significant technological improvement over the last decade and gained tremendous popularity. scRNAseq is an improvement over prior pooled RNA analyses which cannot identify the cellular composition and heterogeneity of a tissue of interest. This new approach offers new opportunity for new discovery, as tissue samples can now be sub-categorized into groups of cell types based on genome-wide gene expression in an unbiased fashion. As ophthalmologists, we are uniquely positioned to obtain pathologic samples from the eye for further study. ScRNAseq has already been applied in ophthalmology to characterize retinal tissue, and it may offer the key to understanding various pathological processes in the future.

Positioning of a morbidly obese patient during retinal surgery.

A body mass index (BMI) ≥35 kg/m2 is classified as obese, and a BMI ≥40 kg/m2 is classified as morbidly obese. Obese people are at a higher risk for developing cardiovascular complications like ischemic heart diseases, congestive cardiac failure, hypertension, type 2 diabetes mellitus and obstructive sleep apnea (OSA) among other health issues. Central obesity can also increase the pleural pressure and cardiac filling pressures, thus increasing the intracranial (ICP) and intraocular pressure (IOP). These clinical co-morbidities can make retina surgeries, which require patient in supine position for 45-90 minutes, a challenging task. We present our experience in the intraoperative positioning of such a patient who underwent surgery for retinal detachment.

Intraocular silicone implant to treat chronic ocular hypotony-preliminary feasibility data.

PURPOSE: Ocular hypotony secondary to proliferative vitreoretinopathy-related retinal detachment, trauma or inflammation is difficult to treat. Besides endotamponades such as silicone oil, vitreous implants such as iris diaphragms or balloons have been developed to stabilize the eye and to prevent phthisis of the globe. Vitreous implants tested thus far exhibit a seam at the attachment site of the hemispheres, or micropores. This manuscript reports the development of a seamless silicone balloon implant without micropores, which can be filled with silicone oil and surface-modified to improve its biocompatibility. Developed for intraocular placement in the management of chronic hypotony and phthisis prevention, it may also be suitable for tamponading retinal detachments. METHODS: Silicone was used as the basic structure for the fabrication of a seamless balloon-shaped intraocular implant, which was coated by employing a six-arm star-shaped (sP) macromer of a copolymer of 80 % ethylene oxide (EO) and 20 % propylene oxide (PO) with conjugated functional terminal isocyanate groups, NCO-sP(EO-stat-PO), with and without heparin. Three variants of implants, which differ in their surfaces, were manufactured: uncoated silicone, NCO-sP (EO-stat-PO) coated silicone and heparin-NCO-sP (EO-stat-PO) coated silicone implants. To exert a tamponade effect, the implant was filled with silicone oil and its properties were studied. RESULTS: Seamless thin balloon implants made of silicone, which are considered biocompatible and intrinsically resistant to biological attacks in vivo, could be fabricated in different sizes. The silicone oil-filled implant can mimic the mechanism of buoyant force and high surface tension of silicone oil, which is the only long-term vitreous substitute currently available. The silicone oil-filled implant can also mimic the natural vitreous body by occupying the entire posterior segment. CONCLUSIONS: The intraocular silicone implant as an alternative long-term treatment of chronic ocular hypotony might offer a new option for clinical ophthalmological practice. In vivo studies need to be performed to collect more data on the implant's long-term mechanical and optical properties, as well as long-term biocompatibility.

Experimental study of limited macular translocation / 中华眼底病杂志

Objective By using a newly developed animal model of limited macular translocation (LMT) in rabbit eyes, to explore the complications,indications and predictability of LMT. Methods LMT models were performed in 15 rabbit eyes, and were divided into 4.5 mm group and 3.5 mm group by the length of scleral shortening.The effect of retinal translocation (distance and direction) and its complications were analyzed. In a separated group, postoperative corneal astigmatism was studied after release of scleral shortening suture 1 month after LMT. In order to study the impact of neuroretina retinal pigment epithelium (RPE) adhesion on LMT, retinas and choroids in 4 pigmented rabbit eyes were pretreated with photocoagulation. Results Success rate of LMT was 86 7%. In these cases, retinal translocations were achieved [(distance of 610 to 2 690 ?m, [AKx-]?s =(1 395?636) ?m; translocation angle ? of 10 38?, ?s =(22.7?8.3) ?]. The difference in scleral shortening between 4.5 mm and 3.5 mm groups did not significantly influence the final translocation. Major complications of LMT included intraocular bleeding, retinal break, and corneal astigmatism. Release of scleral shortening suture reduced corneal astigmatism and made it more regular, meanwhile, retinal translocation did not regress. The neuroretina RPE adhesion induced by retinal photocoagulation made neuroretinal hydrodissection difficult, and led to retinal break readily. . The difference in scleral shortening between 4.5 mm and 3.5 mm groups did not significantly influence the final translocation. Major complications of LMT included intraocular bleeding, retinal break, and corneal astigmatism. Release of scleral shortening suture reduced corneal astigmatism and made it more regular, meanwhile, retinal translocation did not regress. The neuroretina RPE adhesion induced by retinal photocoagulation made neuroretinal hydrodissection difficult, and led to retinal break readily. Conclusion Sufficient LMT models in rabbit eye were obtained with few postoperative complications. Direction of retinal translocation is an important factor influencing the effect of LMT, except for distance. Release of scleral shortening suture can effectively reduce corneal astigmatism without causing regression of retinal translocation. For the patients with a history of macular or para macular photocoagulation, LMT should be performed carefully.

Vitreoretinal surgery using the 25G transconjunctival sutureless vitrectomy system under topical anesthesia / 中华眼底病杂志

Objective To evaluate the indications, effectiveness and complications of vitreoretinal surgery using the 25G transconjunctival sutureless vitrectomy system (TSV25G) under the topical anesthesia. Methods The clinical and follow-up data of 22 eyes of 22 patients undergone vitreo-retinal surgery using TSV25G under the topical anesthesia were retrospectively analyzed. All of the patients were monocular sickened, including idiopathic macular hole in 10 eyes, idiopathic macular pucker in 6, vitreoretinal traction syndrome in 4, and vitreous hemorrhage associated with branch retinal vein occlusion in 2. Peeling of epiretinal membrane and/or internal limiting membrane, intraocular laser coagulation, air-fluid exchange and tamponiding of C 3F 8 were performed according to the condition of diseases. The postoperative follow-up was 1-11 months, with the mean duration of 6.4 months. The effect of analgesia, cooperation with the patients, operative effect and complications in and after the surgery were observed. Results The operations finished successfully in all of the eyes under the topical anesthesia. The operation duration ranged from 20 to 25 minutes with average of 22 minutes. The patients cooperated with the doctor well without any discomfort. Two days after the surgery, edema of the wounded conjunctiva was found, and recovered 7 days later. A light pigment dot on the surface of the sclera could be seen at the first month. The complications included transient increasing of intraocular pressure in 2 eyes, feather-like opacity of lens in 5 eyes, vitreous hemorrhage in 1 eye, and air-bleb under conjunctiva in 2 eyes. No other complications related with the cut were found. The macular hole closed in 9 eyes with idiopathic macular hole, and the other 1 had the smaller but not closed hole. Idiopathic macular pucker, vitreoretinal traction syndrome, and vitreous hemorrhage associated with branch retinal vein occlusion were cured successfully. Conclusions Vitreoretinal surgery using the TSV25G under the topical anesthesia has many advantages such as simple procedure, short operation time, micro-invasion, less complications and rapid revovery, and mainly serves simple manipulation in some simple diseases such as idiopathic macular hole, vitreo-retinal traction syndrome, and simple hemorrhage.

Experimental research of intraocular retention of domestic perfluorocarbon liquid / 中华眼底病杂志

Objective To investigate the effect of long-term intraocular retention of domestic perfluorocarbon liquid (PFCL) on morphology and histology of ocular tissues. Methods A total of 18 New-Zealand rabbits were randomly divided into 3 experimental groups, whose left eyes underwent intraocular injection with 0.3, 0.6, and 1.0 ml PFCL, respectively. All of the right eyes of the rabbits were in the control group. The morphological, electrophysiological and histological changes of the ocular tissue were observed 4, 8, and 12 weeks after the injection. Results No clinically significant retinopathy but only mild morphological changes were found in group 1 and 2, while obvious morphological and histological changes were found in group 3. Mild morphological and histological changes were found in all of the rabbits 4-8 weeks after the injection while significant ones were found 8-12 weeks after the injection. The results of electroretinography indicated a statistically significant decline of amplitude of b wave in group 3. Conclusions Long-term intraocular retention of few PFCL may cause mild histological changes but not affect the clinical function. Plentiful PFCL remains in eyes may lead to toxic reaction to the ocular tissue.

Relaxing retinotomy for the treatment of perforating traction retinal detachment / 中华眼底病杂志

Objective To explore the therapeutic value and effects of relaxing retinotomy for perforating traction retinal detachment(PTRD). Method A retrospective survey was done in 21 patinets (21 eyes) with PTRD who underwent vitrectomy combined with relaxing retinotomy in our hospital from 1998 to 2001. Results The retinae were completely reattached in all 21 cases. The visual acuity of 12 patients (57%) was counting finger, and the best visual acuity was 0.05. Among the 18 patients who were followed up for 6 to 25 months, 14(77.8%) remained retinal reattachment. Conclusions Relaxing retinotomy is effective for anatomic reattachment of PTRD, especially to the patients with retinal incarceration and severe proliferative vitreoretinopathy.

THE USE OF DOMESTIC PERFLUOROTRIBUTYLAMINE FOR THE MANAGE-MENT OF GIANT RETINAL TEARS / 中华眼底病杂志

We used domestic perfluorotributylamine to treat 21 eyes with giant retinal tears, including 5 rhegmatogenous retinal detachment with folded and fixed flap and 16 giant retinal tears resulting from retinotomy and retinectomy due to complicated retinal detachment. The success rate of retinal reattachment was over 95%, with no serious side effects. The activities and complications of perfluorotributylamine in the mangement of giant retinal tears were discussed.

Factors influencing the therapeutic efficacy of Argon laser photocoagulation on proliferative diabetic retinopathy / 眼科

108 eyes of proliferative diabetic retinopathy were treated with Argon laser panretinal photocoagulation. Three months after treatment, The systemic and local factors influencing the therapeutic effecacy were treated by "stepwise discriminations analysis" to tind that the relevant factors included the severity and location of neovascularization and the total doses of laser irradiation. For eyes with papillar or mutiple and low dosage of laser irradiation, the therapeutic efficacy was poor.

Laser photocoagulation for the treatment of retinal periphlebitis / 眼科

39 cases (49 eyes) with retinal periphlebitis (Eales' disease) were treated by laser photocoagulation and followed up for 3～64 months, averaging 17 months. The visual acuity improved in 29 eyes (59.1％), remained unaltered 15 eyes (30.7％),and diminished in 5 eyes (10.2％). The results showed that laser photocoagulation was effective and safe for the treatment of Eales' disease. The importance of early diagnosis, early treatment, periodical follow-up and the use of corticosteroids were discussed.

Laser panretinal photocoagulation for the treatment of diabetic retinopathy / 眼科

213 eyes (138 cases)with diabetic retinopathy (DR) were treated with laser panretinal photoeoagulation(PRP)and followed up for 3～72 months, during which time the visual acuity improved in 70 eyes (32.9％), remained unaltered in 77 eyes(36.1％), and diminished in 66 eyes (31％). The results indicated that PRP for the treatment of DR was effective and safe, with few complications. Factors affecting performance of the technique and visual prognosis were discussed.