Successful retrieval of internal limiting membrane specimens.
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Alcian Blue↗
Biomedical subjects
C Groenewald
Publications and source records attributed to C Groenewald.
Visual loss following removal of intraocular silicone oil.
AIM: To investigate the cause of visual loss following removal of intraocular silicone oil in patients who underwent vitrectomies for retinal detachment or giant retinal tear. METHODS: The clinical records of three cases with visual loss following removal of silicone oil were reviewed. Investigations carried out included fundus fluorescein angiogram, optical coherence tomography, and electrophysiological studies. RESULTS: Visual acuities dropped from 6/9 to 6/36 in two cases and 6/24 to 3/24 in the third. None of the three cases had macula detachment at any stage. Fundus fluorescein angiogram and optical coherence tomography were normal in all cases. Pattern electroretinogram showed reduced amplitudes of the P50 and N95 components. Multifocal electroretinogram indicated a selective damage to the central part of the macula. CONCLUSIONS: The results suggest that the abnormality arises predominantly in the central part of the macula, especially the outer and middle layers. However, the exact mechanism still remains obscure.
Adult↗
A pilot study on the use of a perfluorohexyloctane/silicone oil solution as a heavier than water internal tamponade agent.
AIMS: To report a prospective two centred non-comparative interventional pilot study of a solution of perfluorohexyloctane and silicone oil (Densiron-68) as a heavier than water internal tamponade. METHODS: 42 consecutive patients were recruited. The indications include proliferative vitreoretinopathy, retinal detachments arising from inferior retinal breaks, and inability to posture. RESULTS: The success rate with one operation using Densiron was 81% and with further surgery 93%. At the end of the study all tamponade agents were removed in 90% of patients. Visual acuity improved from mean logMAR of 1.41 (SD 0.64) to 0.94 (SD 0.57), p = 0.001. There was little evidence of dispersion and excessive inflammation. CONCLUSION: This new tamponade agent is being compared to conventional silicone oil in a prospective international randomised trial.
Adult↗
Case selection in macular relocation surgery for age related macular degeneration.
BACKGROUND: To date there has been no randomised controlled trial demonstrating the safety and efficacy of macular relocation surgery (MRS) for age related macular degeneration (AMD). Vision can be improved in some patients and made worse in others despite successful surgery or because of complications. PURPOSE: To determine which patients would benefit from MRS. METHODS: Twenty nine patients with exudative AMD took part in a prospective, non-comparative, interventional study. Macular relocation surgery involved phacoemulsification, vitrectomy, 360 degrees retinotomy, excision of choroidal neovascular membrane, and macular relocation using an infusion of 5-fluorouracil and low molecular weight heparin as adjuvant to prevent proliferative vitreoretinopathy. Patients underwent protocol refraction preoperatively and six-monthly postoperatively by designated optometrists. Preoperative fundus fluorescein angiograms were read by masked observers and the lesions were classified according to a set protocol. The main outcome measures were visual improvement, final vision of better than 20/400, reading speed, critical print size. Logistic and multiple stepwise linear regressions were used to identify independent factors which predicted the main outcomes. RESULTS: Preoperative visual acuity (20/120 or worse) and lesion type (predominantly classic or submacular haemorrhage) were significantly associated with visual improvement (coefficient of regression B = 26.8, p<0.001 and B = 14.9 with p = 0.045 respectively). There were no significant independent factors which predicted a final distance logMAR visual acuity of 1.3 (20/400) or any arbitrary definition of blindness. CONCLUSIONS: The study showed that it was possible to select cases that were more likely to experience an improvement in vision following MRS.
Aged↗
Multifixation campimetry on line: a perimeter for the detection of visual field loss using the internet.
More widespread perimetry would improve opportunities for preventing visual handicap from ocular and intracranial diseases, some of which are life threatening. With internet access becoming more ubiquitous, the authors have developed multifixation campimetry on line, for qualified practitioners and lay individuals around the world, free of charge.
Humans↗
Trypan blue staining of internal limiting membrane and epiretinal membrane during vitrectomy: visual results and histopathological findings.
AIMS: To report on the use of trypan blue (TB) 0.06% for staining the internal limiting membrane (ILM) and epiretinal membrane (ERM) during vitrectomy and report on their histology. METHOD: 14 consecutive patients with idiopathic macular hole or macular pucker (seven patients each) were prospectively recruited for ILM or ERM peel respectively. After pars plana vitrectomy and induction of posterior vitreous detachment, 0.5 ml TB 0.06% in phosphate buffered saline (VisonBlue) was injected over the posterior pole in an air filled eye and left for 2 minutes. The stained tissue was peeled with intraocular forceps. Specimens were evaluated using histochemical and immunohistochemical methods. RESULTS: The average follow up was 4.4 months. Internal limiting membranes and epiretinal membranes were stained satisfactorily in all cases and removed successfully. Eight patients (57%) had improvement of 2 or more Snellen lines. All seven macular holes closed. In the ERM cases, no residual membranes were observed clinically, at the latest follow up. No complications relating to the use of the dye were encountered intraoperatively or postoperatively. Of the 14 procedures, nine (four macular hole and five macular pucker) yielded sufficient tissue for histopathological evaluation. Histological and immunohistological assessment revealed that the morphology of these specimens was similar to that observed in macular hole ILM and macular pucker ERM removed without the aid of dye. CONCLUSION: TB staining facilitated the identification and delineation of ILM and ERM removal during the surgical management of macular holes and macular pucker. The visual outcome of this series and the specimens removed suggest they are no different from those without TB staining. Its use in posterior segment appears to be safe but further studies are required to investigate its long term safety.
Adult↗
Treatment of retinal folds using a modified macula relocation technique with perfluoro-hexyloctane tamponade.
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Electroretinography↗
Vitreous penetration of levofloxacin in the uninflamed phakic human eye.
AIMS: To assess the vitreous penetration of oral levofloxacin (a new fluoroquinolone antibiotic with improved Gram positive activity) in uninflamed phakic eyes. METHODS: 15 patients for macula hole surgery were recruited to the study. 10 received a single 500 mg dose of levofloxacin by mouth preoperatively. Five acted as controls. Serum and undiluted vitreous samples were obtained at surgery and analysed by HPLC. RESULTS: Levofloxacin was detectable 2.5 hours after administration in the vitreous. A peak concentration of 1.6 microg/ml (or mg/l) was measured between 2.5 and 4 hours post-dose. CONCLUSION: Oral levofloxacin reaches the vitreous rapidly in the uninflamed phakic eye. Levels did not reach MIC(90) for the commonest infecting organisms. Nevertheless, levofloxacin would be expected to be active against a higher proportion of infecting organisms than either ciprofloxacin or ofloxacin.
Administration, Oral↗
New surgical approach in the management of pseudophakic malignant glaucoma.
PURPOSE: To describe a new surgical approach in the management of pseudophakic malignant glaucoma. DESIGN: Noncomparative case series. PARTICIPANTS: Five consecutive patients with pseudophakic malignant glaucoma. METHODS: All patients underwent zonulo-hyaloido-vitrectomy. The procedure involves the performance of zonulectomy, hyaloidectomy, and anterior vitrectomy (zonulo-hyaloido-vitrectomy) through a peripheral iridectomy or iridotomy via the anterior chamber. MAIN OUTCOME MEASURES: Medications, visual acuity, intraocular pressure, and anterior and posterior segment findings were recorded before and after surgery. RESULTS: Resolution of the malignant glaucoma was achieved in all cases. No recurrences were observed after a median follow-up of 5.5 months (range, 1-9 months). In one patient with extensive anterior synechiae, bleb failure occurred after the resolution of the malignant glaucoma. This patient was treated successfully with a guarded filtration procedure supplemented with 5-fluorouracil. No other complications were observed. CONCLUSIONS: Zonulo-hyaloido-vitrectomy via the anterior segment appears to be an alternative option in the treatment of patients with pseudophakic malignant glaucoma.
Aged↗
Determinants of visual outcome after pars plana vitrectomy for posteriorly dislocated lens fragments in phacoemulsification.
PURPOSE: To evaluate the visual outcome of patients with posteriorly dislocated lens fragments after phacoemulsification managed with pars plana vitrectomy (PPV) and identify risk factors for poor visual outcome. SETTING: Vitreo-Retinal Service, St. Paul Eye Unit, Liverpool, United Kingdom. METHODS: The medical records of all patients who had PPV for posteriorly dislocated lens fragments after phacoemulsification between March 1993 and August 1998 were retrospectively reviewed. Demographics, preexisting eye conditions, details of the previous cataract surgery, findings at presentation, details of the vitreoretinal procedure, final visual acuity, and complications observed during the follow-up were evaluated. Univariate and multiple regression analyses were used to determine the significance of these clinical variables as determinants of poor visual outcome (visual acuity 6/12 or worse). RESULTS: Of the 106 patients identified, 89 had a full set of data and were included in the study. In 79 patients (89%), PPV was performed from 1 to 357 days (median 15 days) after cataract extraction. In 10 patients (11%), PPV was done on the same day as the cataract surgery. Sixty-two patients (69%) had a final visual acuity of 6/12 or better. Preexisting eye disease (P <.01), PPV delayed for more than 4 weeks (P <.03), occurrence of retinal detachment after vitrectomy (P <.01), and the use of ultrasound (US) fragmentation (P <.01) were statistically significantly correlated with a poor visual outcome. CONCLUSIONS: Posterior dislocated lens fragments after phacoemulsification were safely retrieved using PPV. It appears that intervening early (within 4 weeks) and avoiding the use of US fragmentation are associated with a better visual outcome and reduced rate of postoperative complications.
Aged↗
Modulation of retinal pigment epithelial cell behavior by Agaricus bisporus lectin.
PURPOSE: To determine whether Agaricus bisporus lectin (ABL) binds retinal pigment epithelial cells (RPEs), to conduct a preliminary viability study of RPEs exposed to ABL, and to evaluate the effects of ABL on RPE proliferation and RPE-mediated matrix contraction in vitro. METHODS: Using cultured bovine RPEs, immunohistochemistry was used to study ABL binding. Morphologic and trypan blue exclusion techniques were used for toxicity studies. The effect of ABL on RPE proliferation was investigated by [methyl-3H]-thymidine incorporation. The effect of ABL on RPE-mediated matrix contraction was evaluated with RPE-populated three-dimensional collagen matrices. RESULTS: ABL bound to RPE cells. This binding was inhibited by asialomucin. No change in RPE morphology or trypan blue exclusion compared with controls was observed in RPEs incubated with 5 to 60 microg/ml ABL for 3 days. Twenty-four-hour incubations of RPEs with ABL significantly inhibited RPE proliferation in a dose-dependent way, 40 microg/ml ABL inhibited proliferation by 83% (SE 14, P<0.05). ABL showed a dose-dependent significant inhibition of RPE-mediated collagen matrix contraction over 3 days, with 93% inhibition compared with controls by 40 microg/ml lectin (P<0.05). The inhibitory effect of ABL on proliferation and gel contraction was partly reversible after eliminating ABL from the culture medium. CONCLUSIONS: Bovine RPE cells bind ABL, and preliminary evaluations suggest that levels of ABL that are nontoxic to the cells potently inhibit RPE proliferation and RPE-mediated matrix contraction. ABL deserves further investigation as a potential inhibitor of RPE proliferation and cell-mediated matrix contraction in anomalous reparative processes such as proliferative vitreoretinopathy and as a laboratory tool for RPE behavioral studies.
Animals↗
Visual function and patient satisfaction after macular hole surgery.
PURPOSE: Over recent years success in macular hole surgery has increased in terms of anatomical closure. However, debate still continues on the benefit to the patient in terms of visual outcome. We designed a prospective study to investigate the outcome of full thickness macular hole (FTMH) surgery in terms of anatomical closure, visual outcome, incidence of complications and patient satisfaction. METHODS: Thirty eyes of 30 consecutive patients with FTMH were prospectively studied (stage 2 = 2; stage 3 = 23; stage 4 = 5). All cases had surgery involving vitrectomy, injection of an autologous platelet aggregate over the hole and gas tamponade. At 3 months post-operatively all cases were assessed for closure of the FTMH, Snellen acuity and the incidence of complications. At this stage all patients completed a patient satisfaction questionnaire. RESULTS: Anatomical closure of the hole was achieved in 83% of cases (25/30). Visual improvement of 2 Snellen lines or more occurred in 50% of cases (15/30). A vision of 6/12 or better was achieved in 27% of cases (8/30). A post-operative lens opacity was present in 46% (13/28) of phakic patients and a temporal, peripheral wedge-shaped field defect occurred in 17% (5/30) of cases. In this study, 53%, 70%, 57% and 67% of patients gave a positive response to specific questions about satisfaction with near, intermediate and distance vision and overall visual function respectively. CONCLUSIONS: Although the anatomical success of FTMH surgery is high the functional outcome in terms of Snellen acuity is less rewarding. Analysis of patient satisfaction suggests that the arbitrary visual outcome measures presently used may underestimate the functional benefit to the patient. Improved objective measures of visual outcome are required to assess the benefit of surgery in these cases.
Aged↗
Local anaesthesia for vitreoretinal surgery: a case-control study of 200 cases.
PURPOSE: In the United Kingdom the majority of vitreoretinal (VR) surgery is performed under general anaesthesia (GA). The aim of this study was to demonstrate the scope of local anaesthesia (LA) for VR surgery, to measure the acceptance of LA to patients and surgeons and to compare the surgical outcomes, complication rates and duration of the surgical procedures under LA and GA. METHODS: A case-control study was undertaken to compare 100 cases performed under LA with 100 matched cases performed under GA. The matching of cases was based on multiple criteria such as configuration and complexity of retinal detachment, the involvement of the macula, the number and site of retinal tears, presence and severity of proliferative vitreoretinopathy, experience of the surgeon and the type of the surgical procedure. A clinical audit was also carried out on 65 successive patients using a questionnaire to determine the acceptability of LA to patients and surgeons. RESULTS: Anatomical and visual success rates, and intra-operative and post-operative complications, were similar in cases carried out under LA and GA. The mean duration of the surgery (excluding anaesthetic time) was significantly shorter for LA than GA procedures (p < 0.001). The acceptance for LA was high for both patients and the operating surgeons. CONCLUSIONS: We found that VR surgery can be safely and efficiently performed under LA. Adoption of LA has increased our throughput.
Anesthesia, General↗
Endoresection of choroidal melanoma.
AIMS: The results of 52 endoresections for choroidal melanoma are reported. METHODS: The current technique involves vitrectomy, retinal incision over or peripheral to the tumour, haemostasis by raising intraocular pressure and by moderate hypotensive anaesthesia, choroidal incision around tumour, endoresection with vitrector, endodiathermy to bleeding points and residual tumour, fluid-air exchange to reattach retina, endolaser to achieve retinal adhesion around the coloboma and destroy residual tumour in the sclera, silicone oil injection with removal after 12 weeks, cryotherapy to the sclerotomies, and adjunctive ruthenium plaque radiotherapy in selected cases. RESULTS: Patients receiving primary endoresection had a mean age of 53 years, a mean largest basal tumour diameter of 8.2 mm, and a mean tumour thickness of 3.9 mm. 40 tumours extended to within 2 disc diameters of the optic disc, with 17 involving disc. Follow up ranged from 40 days to 7 years (median 20 months). At the last visit, 90% of eyes were retained, with vision of 6/6-6/12 (two), 6/18-6/36 (three), 6/60 to counting fingers (18), hand movements (nine), and light perception (four). The main complications were retinal detachment in 16 and cataract in 25. Secondary endoresection (11) was performed after plaque radiotherapy (four), photocoagulation (four), trans-scleral local resection (two), and proton beam radiotherapy (one), with retention of the eye in nine cases. By the close of the study, no patients developed definite local tumour recurrence but one died of metastatic disease 41 months postoperatively. CONCLUSION: Depending on tumour location, endoresection may conserve central vision or temporal field when radiotherapy would be expected to cause optic neuropathy. Longer follow up is necessary to establish the efficacy of tumour control.
Adult↗
The effect of anaesthesia on the intraocular volume of the C3F8 gas bubble.
Long-acting intraocular gas bubbles are frequently used during vitrectomy to tamponade retinal breaks. The aim of this study was to determine the effect of nitrous oxide anaesthesia on the size and effectiveness of the post-vitrectomy gas bubble. Twenty vitrectomy procedures with injection of 12% perfluoropropane (C3F8) gas were performed. For 10 of the cases routine anaesthesia with nitrous oxide was used and for 10 cases non-nitrous anaesthesia with propofol was used. The volume of the intraocular gas bubble was estimated 24 hours post-operatively using A-scan biometry. At 24 hours the gas bubble occupied a mean of 65.1% of the eye in anaesthesia with nitrous oxide and a mean of 66.1% in anaesthesia with intravenous propofol. The wide range of values of gas-fill recorded at 24 hours makes comparison of the two groups inappropriate. Several factors may account for this spread of values, but in our opinion it is the uncontrolled leakage from the sclerostomies which is the most likely. This study suggests that anaesthesia using nitrous oxide does not adversely affect the size of the C3F8 gas bubble at 24 hours post-vitrectomy when compared with anaesthesia without nitrous oxide.
Adult↗
Does cryotherapy before drainage increase the risk of intraocular haemorrhage and affect outcome? A prospective, randomised, controlled study using a needle drainage technique and sustained ocular compression.
AIMS/BACKGROUND: A prospective, randomised, controlled clinical trial was conducted to investigate the effect of performing cryotherapy before drainage of subretinal fluid (SRF) on the incidence of intraocular haemorrhage (IOH) in the management of retinal detachment. METHODS: Eighty eyes of 80 patients with rhegmatogenous retinal detachment requiring SRF drainage were recruited. Thirty four cases were randomised to receive drainage before cryotherapy (drainage, air injection, cryotherapy, and explant = DACE group) while 46 cases had drainage after cryotherapy (cryotherapy, drainage, air injection, and explant = CDAE group). All cases had trans-scleral drainage of SRF using a 27 gauge hypodermic needle combined with prolonged, intraocular hypertension. RESULTS: There was a low incidence of IOH associated with drainage in both groups with no statistically significant difference between the groups (DACE group = 2.9%; CDAE group = 4.3%; p = 0.43). There was no significant difference between the groups in the rate of anatomical success with a single operation (DACE group = 82.4%; CDAE group = 86.9%; p = 0.38). There was no significant difference between the groups in the visual outcome. An improvement of two Snellen lines or more occurred in 52.9% of the DACE group and in 56.5% of the CDAE group (p = 0.93). CONCLUSION: It was concluded that the surgical sequence of applying cryotherapy before drainage of SRF can be safely and effectively performed. The sequences CDAE and CDE, when air injection is not required, along with DACE should all be part of the surgical repertoire for the management of retinal detachments.
Adolescent↗