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Methicillin resistance of bacteria isolated from vitreous fluid from patients undergoing vitrectomy.

PURPOSE: The aim of this study was to compare the resistance patterns of bacteria in vitreous fluid from patients undergoing vitrectomy for diagnostic reasons, with bacteria of other nosocomial infections. METHODS: Vitreous fluid samples (n=144) were obtained from 133 patients undergoing vitrectomy for endophthalmitis, and 11 for uveitis as suspected endophthalmitis. They were Gram stained and cultured. Antibiotic susceptibility tests were run on all isolates. RESULTS: Gram stains were positive in 45/144 cases (31%), among which 38/45 (84%) were confirmed by a positive culture. Cultures were positive in 74/144 patients (51%) with mainly coagulase-negative staphylococci (n = 44) and Staphylococcus aureus (n = 13). In 133 patients endophthalmitis occurred after lens implantation (80 cases) and in 53 cases there was another origin (e.g. corneal transplantation, endogenous). In 26/80 post-lens implantation infections, culture remained negative; 32 infections occurred with coagulase-negative staphylococci, 10 with Staphylococcus aureus, 9 with streptococci and 3 with gram-negative bacteria. For endophthalmitis, ophthalmologists in our institution give an intraocular injection of vanccmycin and ceftazidim after vitrectomy. Among the 44 isolates of coagulase-negative staphylococci, 12 (27%) were resistant to methicillin. This is in contrast to other hospital-related coagulase-negative staphylococcus infections in general, and the resistance rate is 75% in our hospital. Only 2/13 Staphylococcus aureus isolates were methicillin-resistant. CONCLUSIONS: We conclude that isolates of coagulase-negative staphylococci from vitreous fluid are less resistant to methicillin than those isolated in other nosocomial infections.

Adult↗

Anesthesia through a novel retrobulbar catheter provides perioperative pain control for 24 h after pars plana vitrectomy.

PURPOSE: The purpose of this study was to assess the retrobulbar catheter technique for perioperative pain control in pars plana vitrectomy. METHODS: One hundred consecutive pars plana vitrectomies (duration 20-220 minutes) in 88 patients (age range 37-88 years) were performed by the same surgeon under retrobulbar anesthesia using a commercially available retrobulbar needle. Initially, 7 ml of mepivacaine 2% were injected, a 28-gauge flexible catheter was introduced into the retrobulbar space and the needle was withdrawn. The catheter was removed 24 h after surgery. Intraoperatively and postoperatively, the patients were asked to rate pain using a numerical scale from 0 to 10. When pain was more than grade 3, 2 ml of a local anesthetic were re-injected through the catheter. RESULTS: A first re-injection was given intraoperative/y 53.0 +/- 34.6 minutes after the start of surgery during 35/100 procedures, and second and third injections were needed during 12 /100 and 4/100 procedures, respectively. The first postoperative re-injection was given 3.9 +/- 1.5 hours after the start of surgery in 54 procedures, and second and third injections were carried out in 35/100 and 10/100 procedures respectively. CONCLUSIONS: The results suggest that a temporary indwelling retrobulbar catheter allows long-lasting titratable local anesthesia during pars plana vitrectomy and titratable postoperative analgesia.

Adult↗

Comparative study of vitrectomy with and without vein decompression for branch retinal vein occlusion: a pilot study.

PURPOSE: To report the clinical outcomes in patients undergoing pars plana vitrectomy with and without vein decompression for treatment of branch retinal vein occlusion (BRVO). METHODS: Thirty-five eyes with macular edema and visual acuity worse than 20/100 secondary to BRVO were prospectively evaluated. Vitrectomy with posterior hyaloid removal and vein decompression at the arteriovenous crossing was performed on 15 eyes (Group 1); consecutively, the same technique without vein decompression was performed on 20 eyes (Group 2). Primary outcome was visual acuity and secondary outcomes were resolution of macular edema and development of neovascularization. RESULTS: No differences were found between groups in either patient age (p = 0.566) or preoperative visual acuity (p = 0.505). No differences were found in visual acuity at 3 (p = 0.651), 6 (p = 0.697), 9 (p = 0.763), 12 (p = 0.881), or 18 (p = 0.748) months. Mean time for macular edema resolution and visual acuity improvement was 9 months in both groups, with a mean improvement of 3.5 +/- 2.35 lines in Group 1 and 3.2 +/- 2.97 lines in Group 2. No eyes in either group developed new vessels. CONCLUSIONS: Results suggest that vitrectomy with posterior hyaloid removal without vein decompression can resolve macular edema, improve vision, and prevent development of new vessels in BRVO.

Aged↗

A simple way to prevent indocyanine green from entering the subretinal space during vitrectomy for retinal detachment due to myopic macular hole.

PURPOSE: To present a safe and simple method of preventing indocyanine green (ICG) from entering the subretinal space in patients undergoing vitrectomy for retinal detachment caused by myopic macular hole. PATIENTS AND METHODS: Four consecutive highly myopic eyes (three phakic, one pseudophakic) with retinal detachment due to myopic macular hole were operated on by pars plana vitrectomy. The ICG-assisted peeling of the internal limiting membrane was performed after temporarily closing the macular hole by means of a small bubble of perfluorocarbon liquid (PFCL) in order to prevent ICG from entering the subretinal space. RESULTS: Retinal reattachment was successful in all patients, and anatomic closure of the macular hole occurred during the follow-up period (range 3 to 10 months). CONCLUSIONS: A small bubble of PFCL prevents ICG dye from entering the subretinal space during vitrectomy for retinal detachment due to macular hole in highly myopic eyes.

Coloring Agents↗

The diagnostic yield of vitrectomy specimen analysis in chronic idiopathic endogenous uveitis.

PURPOSE: The low diagnostic yield of vitrectomy specimen analysis in chronic idiopathic uveitis (CIU) has been related to the complex nature of the underlying disease and to methodologic and tissue immanent factors in older studies. In an attempt to evaluate the impact of recently acquired analytic methods, the authors assessed the current diagnostic yield in CIU. METHODS: Retrospective analysis of consecutive vitrectomy specimens from patients with chronic endogenous uveitis (n = 56) in whom extensive systemic workup had not revealed a specific diagnosis (idiopathic) and medical treatment had not resulted in a satisfying clinical situation. Patients with acute postoperative endophthalmitis served a basis for methodologic comparison (Group 2; n = 21). RESULTS: In CIU, a specific diagnosis provided in 17.9% and a specific diagnosis excluded in 21.4%. In 60.7% the laboratory investigations were inconclusive. In postoperative endophthalmitis, microbiological culture established the infectious agent in 47.6%. In six of eight randomly selected cases, eubacterial PCR identified bacterial DNA confirming the culture results in three, remaining negative in two with a positive culture and being positive in three no growth specimens. A double negative result never occurred, suggesting a very high detection rate, when both tests were applied. CONCLUSIONS: The diagnostic yield of vitrectomy specimen analysis has not been improved by currently routinely applied methods in recent years in contrast to the significantly improved sensitivity of combined standardized culture and PCR analysis in endophthalmitis. Consequently, the low diagnostic yield in CIU has to be attributed to insufficient understanding of the underlying pathophysiologic mechanisms.

Adolescent↗

Vitrectomy for ocular trauma: a question of timing?

PURPOSE: A long-standing controversy exists regarding the proper timing for vitrectomy in a traumatized eye. The present study was conducted to assess the influence of timing on the final visual acuity. MATERIALS AND METHODS: A retrospective review was made of 45 consecutive patients who underwent a pars plana vitrectomy procedure for repair of ocular trauma. The patients were divided into two groups according to the timing of the surgery post-trauma: those operated before or after 14 days. Type of trauma and pre- and postoperative visual acuities were compared. RESULTS: A contusion type of trauma was more frequent in the late surgery group. Sharp, penetrating injuries were more common in the early vitrectomy group. No significant difference was found though visual acuity was worse in the patients with a contusion component to their injury. Timing of surgery seems to have very little effect on the final outcome. CONCLUSIONS: Final visual acuity is determined by the type and extent of trauma rather than the timing of surgery.

Adult↗

Visual fields in patients who have undergone vitrectomy for complications of diabetic retinopathy. A prospective study.

BACKGROUND: To determine the extent of visual field loss in patients who had required a pars plana vitrectomy secondary to complications of proliferative diabetic retinopathy. METHODS: Patients that had undergone a vitrectomy on at least one eye for treatment of either vitreous haemorrhage or tractional retinal detachment were selected for study. ETDRS acuity and Humphrey binocular Esterman visual field testing were performed and compared to the minimum standards for safe driving as defined by the Royal College of Ophthalmologists in 1999. In addition to this Goldman kinetic visual fields using a III4e and V4e stimulus size and central 24-2 threshold test with the SITA-fast strategy were performed on the vitrectomised eye. RESULTS: 20 patients (n = 20) were recruited. Mean visual acuity in the eye being tested was 0.20 (Snellen 6/9.5). Results from the Humphrey field analyzer showed a mean number of abnormal stimulus locations of 71.2% (p < 0.005). 70% of patients had sufficient binocular acuity to drive and of these 71.4% were shown not to have a minimum visual field for safe driving on binocular Esterman field analysis. CONCLUSION: Vitrectomy potentially allows retention/restoration of good visual acuity in patients with complications of proliferative diabetic retinopathy. However patients may be suffering from unrecognized visual impairment consequent upon extensive visual field loss which in over two thirds of patients may be sufficiently severe to preclude safe driving.

Adult↗

Differential recovery of the electroretinogram, visually evoked cortical potential, and electrically evoked cortical potential following vitrectomy: implications for acute testing of an implanted retinal prosthesis.

To determine the extent to which electrophysiologic tests of the afferent visual pathway are affected by vitrectomy, the procedure was performed in 15 eyes of 11 adult Dutch-belted rabbits. An electroretinogram (ERG), visually evoked cortical potential (VECP), and electrically evoked cortical potential (EECP) were obtained preoperatively and sequentially after surgery. For electrical stimulations, biphasic impulses were delivered to the retina. Post-vitrectomy declines of 49, 25, and 41% from the median baseline amplitudes and increases of 13, 18, and 17% from the median baseline latency values were found for ERG, VECP, and EECP, respectively. At 90 min, 13 to 30% of eyes still had an amplitude more than 10% below baseline on at least one of the three tests, whereas 10 to 47% of eyes had an abnormal latency more than 10% above baseline on at least one of the three tests. Amplitudes were more likely than latencies to return to near baseline, but for eyes that remained subnormal, the decline was greater for amplitudes than latencies. Significant alterations in retinal function, manifested by declines in amplitudes and increases in latencies of the ERG, VECP, and EECP, persist in a large proportion of eyes up to 90 min post-vitrectomy.

Animals↗

Pharmacological vitrectomy.

Pharmacological vitrectomy refers to the use of enzymes in an effort to liquefy vitreous and to weaken the adhesion of vitreous cortex to the internal limiting membrane during or before performing vitreous surgery. It is well known that the vitreoretinal interface plays important roles in developing many blinding diseases. To make the vitreous surgery easier for better outcome or to avoid vitrectomy, plasmin, dispase, and chondroinase have been used to promote the disinsersion of vitreous cortex to the internal limiting membrane, a basement membrane of Muller cells. On the other hand, hyaluronidase has been used clinically to facilitate the clearance of vitreous hemorrhage liquefying vitreous body and developing posterior vitreous detachment. This article reviews enzymes as an intraoperative adjunctive agent in vitrectomy.

Collagenases↗

The expanding role of primary pars plana vitrectomy in the treatment of rhegmatogenous noncomplicated retinal detachment.

The surgical management of rhegmatogenous retinal detachment has evolved dramatically during the past 2 decades. Investigators have introduced and refined alternative techniques to scleral buckling surgery including pneumatic retinopexy and primary pars plana vitrectomy (PPV). Rapid parallel developments in instrumentation, including wide-angle viewing systems, perfluorocarbon liquids, novel vitrectomy machines, intraocular tamponades, and endolaser photocoagulators have led to increasing sophistication in primary PPV surgical techniques for the treatment of rhegmatogenous uncomplicated retinal detachment. However, the precise role of primary PPV in new uncomplicated retinal detachment remains debatable owing to the lack of controlled randomized trials. This article examines primary vitrectomy treatment for rhegmatogenous uncomplicated retinal detachment and presents the specific types of retinal detachments for which primary PPV may be optimal, according to personal and reported results, the surgical instrumentation and technique, as well as the complications and limitations of this surgical method.

Humans↗

Vitrectomy for refractory diabetic macular edema.

Diabetic macular edema may occur or worsen as a consequence of vitreomacular traction in some eyes. The precise role of the posterior hyaloid in the pathogenesis of diabetic maculopathy remains unclear. The determination of which eyes might benefit from vitrectomy is the most challenging aspect in the treatment of this condition. Fluorescein angiography, B-scan untrasonography, and optical coherence tomography may be helpful in this regard. Most often, vitreous surgery is performed when diabetic macular edema persists despite multiple laser treatments. All reports published to date regarding vitrectomy for diabetic macular edema are uncontrolled and nonrandomized patient series. Visual improvement after vitrectomy is related to the duration of edema, as well as the extent of intraretinal lipid and vascular nonperfusion.

Diabetic Retinopathy↗

Ahmed valve implantation for refractory glaucoma following pars plana vitrectomy.

PURPOSE: To evaluate the effectiveness of Ahmed valve implantation for refractory glaucoma following pars plana vitrectomy. METHODS: Seventeen eyes of 15 patients suffering from secondary glaucoma following pars plana vitrectomy underwent Ahmed valve implantation. All the eyes were in critical condition, and intraocular pressure could not be controlled with anti-glaucoma medications. Success was characterized by an intraocular pressure less than 22 mmHg and greater than 6 mmHg, regardless of anti-glaucoma medication usage. RESULTS: The total success rate was 83.4% at 6 months and 76.4% at the final visit. The reduction in intraocular pressure and the number of medications used postoperatively were both statistically and clinically significant (p<0.005). Postoperative complications included: transiently increased intraocular pressure, transient hyphema, early postoperative hypotony, choroidal detachment, malposition of the valve tip, and phthisis bulbus. CONCLUSIONS: Ahmed valve implantation is a safe and effective method for refractory glaucoma following vitrectomy.

Adult↗

Posterior continuous curvilinear capsulorhexis with and without optic capture of the posterior chamber intraocular lens in the absence of vitrectomy.

PURPOSE: To evaluate the efficacy of posterior continuous curvilinear capsulorhexis (PCCC) with optic capture of the posterior chamber intraocular lens (PC IOL) in the absence of vitrectomy in preventing secondary opacification of the visual axis following pediatric cataract surgery. PATIENTS AND METHODS: Thirty-four eyes of 28 children with congenital or developmental cataract, aged 1.5 to 12 years (mean, 6.39 years), were included in this prospective, randomized study. Anterior continuous curvilinear capsulorhexis (ACCC) with PCCC without optic capture of the PC IOL was performed in group A (18 eyes) and ACCC with PCCC with optic capture of the PC IOL was performed in group B (16 eyes). None of the eyes underwent anterior vitrectomy. Secondary opacification of the visual axis, visual acuity, and possible complications were observed and analyzed. RESULTS: The follow-up period ranged from 8 to 28 months (mean, 17.5 months). All 16 eyes (100%) in group B had a clear visual axis at the end of follow-up. Eight eyes (44.4%) in group A had significant opacification of the visual axis. The difference between the two groups was statistically significant (P = .0011). No eye in group B required secondary intervention, whereas all 8 eyes in group A with significant secondary opacification required secondary intervention. There was no statistically significant difference in other complications such as anterior chamber reaction, fibrin formation, lenticular precipitates, and posterior synechiae. The final best-corrected visual acuity at the end of follow-up was comparable in the two groups (P > .05). CONCLUSION: PCCC with optic capture of the PC IOL prevents secondary opacification of the visual axis even in the absence of vitrectomy.

Capsulorhexis↗

[Corneal epithelial complications after vitrectomy: a retrospective study].

PURPOSE: To establish the incidence, evolution and final visual outcome of corneal epithelial complications after vitrectomy in a consecutive series performed throughout a period of one year. METHODS: 195 consecutive medical records of patients vitrectomized in 2001 have been retrospectively reviewed. Patients were clinically evaluated the day after vitrectomy, during the first week, and then weekly for 3 months (minimum follow-up). Functional results have been established at the end of this period. RESULTS: 12 out of 195 eyes developed corneal epithelial complications after surgery (6.1%). Eight cases were diagnosed of persistent epithelial defect (4.1%), and four cases (2%) of necrotizing herpetic keratitis. Six out of 12 were diabetic. Corneal epithelial complications affected 10.5% of diabetic and 4.3% of non-diabetic patients (p=0.10). The majority of persistent epithelial defects healed without sequelae in less than two months. Herpetic keratitis required between 3 to 4 months to heal and caused corneal scarring in all cases. CONCLUSIONS: Persistent corneal epithelial defects after vitrectomy are a relatively frequent complication, mainly in diabetic patients. Recurrence of herpetic keratitis must also be kept in mind. This finding has not been previously reported and needs further studies.

Corneal Diseases↗

New iris retractor for pupil dilatation during anterior vitrectomy: double-hook iris retractor.

To report a new iris retractor as a tool for pupillary dilatation in eyes with a small pupil. This instrument was designed to prevent the retractor from dropping out of corneal incision, especially during anterior peripheral vitrectomy requiring a scleral indentation. A new iris retractor was designed with the top in the form of a double-hook, based on the conventional flexible iris retractor. The new instrument was used in 16 eyes, and the conventional flexible iris retractor was used in 14 eyes, with proliferative retinopathy or proliferative diabetic retinopathy in cases in which anterior vitrectomy was performed. The number of times that the instrument has been replaced were recorded. The conventional flexible iris retractor was replaced at mean number of 4.2 times, while the new iris retractor was replaced a mean number of 0.3 times during vitreous surgery. The difference was statistically significant (P = 0.009, Mann-Whitney test). The new iris retractor can easily hook onto the iris and is useful in anterior vitrectomy.

Eye Diseases↗

[A comparative study of visual outcomes following primary vitrectomy and scleral buckling procedures to manage macular off rhegmatogenous retinal detachments].

PURPOSE: To determine the difference between two types of retinal detachment surgery in postoperative visual recovery in the management of macular-off rhegmatogenous retinal detachment. METHODS: We evaluated retrospectively the postoperative visual acuity (VA) in 37 patients who underwent primary vitrectomy (group V) and 39 patients treated with conventional scleral buckling (group S). RESULTS: Although the mean preoperative VA in group V (0.03) was significantly worse (p = 0.04) than that in group S (0.06), there was no statistically significant difference between the groups in postoperative VA throughout the follow-up period. However, in the cases with poor preoperative VA (VA < 0.1), ocular hypotony (IOP < 7 mmHg), or prolonged macular detachment (duration > 7 days), the visual recovery was significantly better (p < 0.05) in group V than in group S from 1 month postoperatively. There were more eyes with a final VA of more than 0.5 in group V than in group S. When considering only the eyes with lenses spared intraoperatively, postoperative cataract progression resulting in secondary visual reduction was statistically significantly greater (p < 0.01) in group V (62%) than in group S (8%). CONCLUSIONS: Primary vitrectomy is effective to attain early visual rehabilitation, especially to manage macula-off retinal detachments with poor preoperative VA, ocular hypotony, and prolonged macular detachment. To prevent a secondary visual reduction, cataract surgery combined with vitrectomy is recommended in selected cases.

Adult↗

[Predicted versus actual postoperative refractive error after simultaneous vitrectomy and cataract surgery].

PURPOSE: We compared the spread between predicted and postoperative actual refractive errors after simultaneous vitrectomy, phacoemulsification, aspiration, and acryl lens insertion and after cataract surgery alone. METHODS: Cataract surgery and vitrectomy (combined surgery group) were performed in 185 eyes, and cataract surgery only (cataract surgery group) in 63 eyes. Vitrectomy was needed for diabetic retinopathy in 104 eyes, macular hole in 26 eyes, rhegmatogenous retinal detachment in 25 eyes, and other conditions in 30 eyes. RESULTS: The spread between predicted and actual refractive errors were +0.19 +/- 1.24 D (mean +/- standard deviation) in the combined surgery group and +0.91 +/- 1.40 D in the cataract surgery group. Gas tamponade in the combined surgery group increased the myopic change more than anything else. CONCLUSION: Actual refractive errors in the combined surgery group were found to shift to myopia more than in the cataract surgery group. Gas tamponade was considered to press the intraocular lens forward in the combined surgery group.

Adult↗

[Vitrectomy for extraction of intraocular foreign bodies].

OBJECTIVE: To evaluate the effect of treatment of intraocular foreign bodies (IOFBs) with vitrectomy and its influential factors. METHODS: A retrospective research was done on 517 in-patients having undergone extraction of IOFBs with vitrectomy. RESULTS: Postoperatively, the successful rate of the extraction of IOFBs was 97.6%, the rate of cases with useful vision (0.05 to 0.4) increased from preoperative 12.5% to 23.2% and that with good vision (0.5 and better) from 7.2% to 17.0% (P < 0.005). When IOFBs were located in anterior segment, vitreous and retina, the increasing rates of cases with useful vision respectively were 44.4%, 25.1% and 10.7%, and that of good vision were 26.3%, 12.7% and 2.7%. CONCLUSIONS: Vitrectomy is favorable for the extraction of IOFBs, the increase of postoperative vision and the management of complications.

Adolescent↗