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Biomedical subjects

D G Charteris

Publications and source records attributed to D G Charteris.

At least 37 records · Page 2Linked to original sources
PubMed2001

Adjuvant 5-fluorouracil and heparin prevents proliferative vitreoretinopathy : Results from a randomized, double-blind, controlled clinical trial.

PURPOSE: To assess the safety and efficacy of adjuvant combination therapy using 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) for prevention of proliferative vitreoretinopathy (PVR) after vitrectomy and retinal reattachment surgery. DESIGN: Prospective randomized, double-masked, placebo controlled trial. PARTICIPANTS: One hundred seventy-four high-risk patients were randomized to receive either 5-FU and LMWH therapy or placebo. Patients were selected from all patients undergoing primary vitrectomy for rhegmatogenous retinal detachment. METHOD: Results of standard surgery with 5-FU and LMWH therapy or placebo were compared at the 6-month follow-up. MAIN OUTCOME MEASURES: Development of postoperative PVR, retinal reattachment at 6 months after surgery, single operation reattachment rate, number of reoperations, and best-corrected visual acuity. RESULTS: There were 87 patients in the 5-FU and LMWH therapy group and 87 in the placebo group. The incidence of postoperative PVR was significantly lower (P = 0.02) in the 5-FU and LMWH therapy compared with the placebo group. In 26.4% (23/87) of the placebo group and in 12.6% (11/87) of the 5-FU and LMWH group, postoperative PVR developed. In the 5-FU and LMWH group, the number of patients undergoing more than one operation was 19.5% (17/87) and the number of reoperations resulting from PVR was 52.9% (9/17). In the placebo group, the number of patients undergoing more than one operation was 25.3% (22/87) and the number of reoperations resulting from PVR was 72.7% (16/22). The difference in visual acuity was not statistically different in the two treatment groups, although those patients in whom postoperative PVR developed tended to have poorer vision (P < 0.0001). There were no differences in complication rates between the two groups. CONCLUSIONS: There is a significant reduction in the incidence of postoperative PVR in patients receiving the 5-FU and LMWH therapy and in the reoperation rate resulting from PVR. This trial shows that incidence of PVR can be reduced with inexpensive and simple pharmacologic treatment with 5-FU and LMWH and should be used routinely in the treatment of patients at risk of developing PVR.

Adolescent↗
PubMed2001

The effect of pars plana vitrectomy in the management of Fuchs heterochromic cyclitis.

PURPOSE: Fuchs heterochromic cyclitis (FHC) is characterized by a unilateral chronic iridocyclitis of insidious onset and uncertain cause. Our aim was to evaluate the effect of vitreous surgery in patients with FHC and clinically significant visual symptoms caused by inflammatory vitreous debris. METHODS: This study was a review of 12 eyes of 12 consecutive patients with FHC who underwent pars plana vitrectomy for visually significant vitreous opacities. Cataract extraction with posterior chamber lens implantation had been performed on four eyes preoperatively. Four eyes had a concomitant lensectomy for cataracts, and one had a surgical posterior capsulotomy. Visual and anatomic data were recorded before surgery and for at least 6 months after surgery. RESULTS: Visual acuity improved in all patients from an average logMAR of 0.57 to 0.007 (P = 0.0004) and by more than 2 Snellen lines in 8 of 12 of the eyes (P < 0.05). Symptoms of floaters resolved in all 11 patients in whom they were a symptom. Vitreous haze was cleared completely from an average Nussenblatt grade of 1.7 to 0 after 1 week (P = 0.0001). CONCLUSIONS: Pars plana vitrectomy is a safe and effective treatment for the visual symptoms associated with FHC and can be combined safely with a lensectomy if required.

Adult↗
PubMed2001

Pars plana vitrectomy and sutured posterior chamber lens implantation.

Transcleral suturing of posterior chamber intraocular lenses (IOLs) was developed to extend the benefits of IOL visual rehabilitation to eyes lacking capsular support and to avoid the complications of closed loop interior chamber IOLs. Although most frequently implanted after complicated cataract surgery or penetrating keratoplasty, they are indicated in several situations following pars plana vitrectomy. The surgical techniques have evolved to minimize the risk of complications, but the surgery remains technically more demanding and time-consuming than insertion of a modern open loop anterior chamber IOL. No randomized trials have compared the relative risks of each lens type, which leaves surgeon preference as the major determinant of what lens is implanted. It is likely, however, that in eyes with extensive anterior chamber angle damage or large iris defects, sutured posterior chamber IOLs will remain the first choice for surgical rehabilitation.

Humans↗
PubMed2001

Soluble TNF receptors in vitreoretinal proliferative disease.

PURPOSE: To measure vitreous levels of soluble TNF-receptors (sTNF-Rs) types I and II in eyes with rhegmatogenous retinal detachment (RRD), uncomplicated or complicated with proliferative vitreoretinopathy (PVR), and in eyes with proliferative diabetic retinopathy (PDR). To examine whether there is any relationship between vitreous levels of sTNF-Rs and clinical features of these conditions and between vitreous sTNF-Rs and TNFalpha levels and serum levels of sTNF-RS: METHODS: Vitreous levels of sTNF-Rs and TNFalpha were measured by enzyme-linked immunosorbent assay in 30 eyes with PVR, 30 eyes with uncomplicated RRD, and 29 eyes with PDR. Vitreous from eyes of 10 deceased donors and 9 eyes with macular holes served as control specimens. Serum levels of sTNF-Rs were measured in 17 patients with PDR and 21 patients with PVR. RESULTS: Vitreous levels of sTNF-Rs I and II were increased in eyes with PVR, RRD, and PDR when compared with control eyes (P < 0.002). However, vitreous levels of sTNF-Rs I and II were higher in eyes with PVR than in eyes with RRD (P < 0.01) or PDR (P < 0.03). This contrasted with the findings that serum sTNF-Rs were higher in PDR than in PVR (P < 0.016) and that vitreous levels of TNFalpha were higher in eyes with PDR than in eyes with PVR (P < 0.0005). In PVR, vitreous sTNF-Rs levels were associated with the duration of retinal detachment, number of previous external operations, and grade of severity, whereas in PDR these levels were not related to the type or duration of diabetes or its complication with traction retinal detachment. CONCLUSIONS: These observations suggest the existence of TNF inhibitory mechanisms within the eye during retinal processes of inflammation and angiogenesis. That high vitreous levels of sTNF-Rs relate to severity of retinopathy suggests that these molecules may constitute reactive products of inflammation. Effective control of TNFalpha activity by sTNF-Rs within the retinal microenvironment may determine the outcome and severity of retinal proliferative conditions.

Diabetic Retinopathy↗
PubMed2000

Matrix metalloproteinases and their natural inhibitors in fibrovascular membranes of proliferative diabetic retinopathy.

AIM: To examine epiretinal membranes of proliferative diabetic retinopathy (PDR) for the presence of selective matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs), in order to determine whether neovascularisation and fibrosis, characteristic of this complication of diabetes mellitus, are associated with specific anomalies of MMP or TIMP expression. METHODS: The presence of selected MMPs and TIMPs was investigated in 24 fibrovascular epiretinal membranes of PDR, and the findings compared with that observed in 21 avascular epiretinal membranes of proliferative vitreoretinopathy (PVR) and five normal retinas. Specimens were examined for deposition of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase A (MMP-2), gelatinase B (MMP-9), and three tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, and TIMP-3). RESULTS: The results showed that unlike normal retina, which constitutively expresses MMP-1 and TIMP-2, a large proportion of PDR membranes (> 62%) stained for MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, and TIMP-3. There were no differences in the expression of these molecules when compared with PVR membranes. A characteristic staining for MMP-9 was observed within the perivascular matrix of PDR membranes, and there was a significant increase in TIMP-2 expression by PDR membranes (p= 0.036) when compared with PVR membranes. CONCLUSIONS: The findings that MMPs involved in degradation of fibrovascular tissue matrix, as well as TIMP-1 and TIMP-2, are found in a large proportion of PDR membranes, and that their expression does not differ from that of PVR membranes, suggest the existence of common pathways of extracellular matrix degradation in pathological processes leading to retinal neovascularisation and fibrosis.

Diabetic Retinopathy↗
PubMed2000

Combined pars plana vitrectomy and sutured posterior chamber implant.

OBJECTIVE: To describe the surgical technique, visual acuity results, and complications of sutured posterior chamber intraocular lenses with complete pars plana vitrectomy. METHOD: A retrospective review of 63 eyes was combined with a telephone survey of the patients and their ophthalmologists. RESULTS: The preoperative diagnoses were trauma, 25 eyes; ectopia lentis, 24 eyes; aphakia following retinal detachment surgery, 7 eyes; cataract surgery, 6 eyes; and endophthalmitis, 1 eye. Mean follow-up was 20 months. Preoperative best-corrected visual acuity was 20/40 or better in 36% (23 of 63 eyes), 20/60 to 20/120 in 33% (21 of 63 eyes), and 20/200 or worse in 31% (19 of 63 eyes) improving to 20/40 or better in 76% (48 of 63 eyes), 20/60 to 20/120 in 18% (11 of 63 eyes), and 20/200 or worse in 6% (4 of 63 eyes) at final follow-up. Preoperative complications included iatrogenic retinal breaks in 3 cases, difficulty with a fixation suture in 1 case, and mild vitreous hemorrhage in 1 case. Postoperative complications included retinal detachment in 2 cases, choroidal hemorrhage in 1 case, intermittent pupil capture in 9 cases, self-limiting vitreous hemorrhage in 3 cases, and late intraocular lenses dislocation in 1 case. CONCLUSIONS: Suturing a posterior chamber implant concurrently, or following, a complete pars plana vitrectomy is a safe procedure. Complete vitrectomy may reduce the rate of long-term complications. Optimal visual rehabilitation can be achieved without the need for contact lens wear with an acceptable additional risk of surgical complications. Arch Ophthalmol. 2000;118:905-910

Adolescent↗
PubMed1999

Pneumatic retinopexy in the treatment of primary rhegmatogenous retinal detachment.

PURPOSE: To review the management by pneumatic retinopexy of 31 primary rhegmatogenous retinal detachments performed between August 1994 and December 1997. METHODS: Ocular indications included superior retinal breaks, no evidence of proliferative vitreoretinopathy (PVR) and ability to posture. Patients with inferior breaks and/or areas of vitreoretinal degeneration were excluded. Surgery was performed under local anaesthetic using sulphur hexafluoride (SF6) or perfluoropropane (C3F8) gas injection. Transconjunctival cryotherapy or laser retinopexy was used to create permanent retinal adhesion. The mean length of patient follow-up was 11 months (range 5-24 months). RESULTS: Thirty-one patients (20 men, 11 women) with a mean age of 63.4 years (range 29-81 years) underwent pneumatic retinopexy which resulted in initial retinal reattachment in 22 patients. Two detachments recurred in the first month and a third at 4 months post-operatively, giving an anatomical reattachment rate with one procedure in 19 out of 31 eyes (61%). Of the 12 failures, 7 were reattached with one additional operation and one case reattached after multiple procedures, giving an overall reattachment rate of 87%. Post-operatively, new or missed breaks were present in 7 patients (22%) and PVR developed in 4 patients (13%). There was no difference in age, gender or extent of detachment between the failed and reattached groups and pseudophakia did not appear to be a poor prognostic factor. CONCLUSION: Pneumatic retinopexy can be a useful alternative to conventional rhegmatogenous retinal detachment surgery in carefully selected cases. A larger study addressing the influence of non-ocular factors is warranted.

Adult↗
PubMed1999

Biofilm on scleral explants with and without clinical infection.

PURPOSE: Biofilm is a glycocalyx matrix secreted by microorganisms that confers protection against host defenses and antimicrobial treatment. Biofilms have been implicated in the persistence of scleral buckle infections. This study aimed to evaluate the incidence of biofilm growth on scleral explants and the relationship to explant infection. METHODS: Scleral explants were obtained following removal for infection or extrusion or during repeat surgery. Explants were fixed with rhuthenium red and examined by scanning electron microscopy to visualize the glycocalyx. RESULTS: A total of 28 explants were analyzed. Ten were removed because of either infection or extrusion and 18 were removed during repeat surgery. The mean time to removal of explants was 36 months in the infection/extrusion group and 12 months in the others. Biofilm was identified on five explants-two removed because of infection/extrusion and three for surgical indications. Bacterial elements were identified in all biofilms. CONCLUSIONS: Biofilm was identified on explants removed because of infection or exposure and on explants removed for technical reasons at repeat surgery. This implies that bacterial contamination and biofilm formation occur without exposure of the explant, probably due to inoculation at the time of initial surgery. Biofilms may contribute to the persistence of scleral explant infections but a causative role in buckle extrusion is unproved.

Biofilms↗
PubMed1999

Retinal detachment associated with excimer laser.

Recent reports of retinal pathology associated with laser refractive surgery are documented. The overall risk of retinal disease following photorefractive keratectomy or laser-assisted in situ keratomileusis is discussed, and the potential causal associations between anterior segment laser and posterior segment pathology are assessed.

Cornea↗
PubMed1999

Retained intravitreal lens fragments after phacoemulsification: a clinicopathological correlation.

AIMS: To explore the relation between clinical course and timing of vitrectomy with the nature and intensity of intraocular inflammatory response in eyes with retained intravitreal lens fragments following complicated phacoemulsification. METHODS: Prospective evaluation of 22 eyes with retained lens fragments with emphasis on corneal clarity, uveitis, intraocular pressure (IOP), timing of vitrectomy, and visual outcome. Numbers of different types of inflammatory cells in vitreous washings were counted, masked to clinical details, in three non-overlapping adjacent high power fields. Relations between clinical and pathological findings were assessed. RESULTS: The IOP was raised in 19 eyes before vitrectomy and remained high in nine postoperatively. The latter had higher median total cell count (104 cells/mm(2)) than those with normal postoperative IOP (37 cells/mm(2)) but this difference was not statistically significantly different (p=0.17). Nine of 22 eyes underwent vitrectomy within 1 week of cataract surgery. Median total cell count in these eyes was 20 cells/mm(2) compared with 140 cells/mm(2) in eyes vitrectomised later-this difference was statistically significant (p <0.001). Final visual acuity was 6/12 or better in 13 eyes, these had fewer intravitreal inflammatory cells than the remaining six with poor visual outcome and no pre-existing cause for this (three patients excluded) (p=0.02). Macrophages were the predominant inflammatory cell type. CONCLUSION: There was significantly less inflammatory cell activity in eyes which had retained lens fragments removed early (within 1 week). Later removal was associated with persistently elevated IOP and poorer visual outcome.

Follow-Up Studies↗
PubMed1998

Vitreolensectomy in Marfan's syndrome.

PURPOSE: To evaluate the effectiveness of pars plana vitreolensectomy in the management of subluxed lenses associated with Marfan's syndrome and to assess the need for intraoperative retinal photocoagulation to prevent post-operative retinal detachment. METHOD: A retrospective review was carried out of 40 eyes of patients with Marfan's syndrome who underwent pars plana vitreolensectomy for subluxed lenses. RESULTS: All patients demonstrated stable or improved visual acuity following surgery with a low incidence of complications. CONCLUSIONS: Pars plana vitreolensectomy is a safe and effective treatment for subluxed lenses in patients with Marfan's syndrome. It appears that intraoperative prophylactic laser treatment need only be applied to areas of lattice degeneration to limit the incidence of post-operative retinal detachment.

Adolescent↗
PubMed1997

Macular hole opercula. Ultrastructural features and clinicopathological correlation.

OBJECTIVE: To investigate the ultrastructural features of idiopathic full-thickness macular hole (FTMH) opercula excised during vitrectomy and to correlate them with the outcome of surgery. METHODS: Opercula were collected from eyes undergoing vitrectomy for stage 3 FTMH using noncrushing, cupped foreign body forceps. Following immediate fixation, specimens were processed for transmission electron microscopy. The ultrastructural features were correlated with the clinical data recorded for each patient before and after surgery. RESULTS: Eighteen specimens were studied. Native vitreous collagen was identified on the surface of all 18, while fragments of internal limiting membrane were present in 11 (61%). Eleven (61%) were found to contain only glia, comprising fibrous astrocytes and Müller cells in variable proportions. The remaining 7 (39%) were found to contain, in addition to glia, neurites and synaptic complexes, of which some were typical of cone photoreceptors. The initial surgical closure rate was significantly better in eyes in which only glia were present (9/11 [82%]), compared with those with neurites (1/7 [14%]) (P = .01). Once closure had been achieved with reoperation, the median final visual acuity was 20/60 in both groups (P = .26), although the likelihood of achieving an acuity of 20/40 or better was greater in the former (50%) than the latter group (17%). CONCLUSIONS: Two distinct types of opercula occur in association with stage 3 FTMH--those containing only glia (pseudo-opercula), which are probably associated with a foveal dehiscence and little or no loss of foveal tissue, and those containing both glia and a significant number of avulsed foveal cones (true opercula), which arise from a full-thickness foveal tear. Although the loss of foveal tissue in true opercula would seem to explain the worse initial anatomical and more modest visual results in some eyes, significant visual improvement may still be achieved after successful closure. The presence of neurites in true opercula suggests that, in at least some cases, direct traction on the foveal retina leads to macular hole formation.

Aged↗
PubMed1997

Retinal detachment following excimer laser.

AIM: To report the clinical presentation, surgical management, and outcome of retinal detachment following excimer laser. METHODS: Retrospective analysis of retinal detachments observed in 11 eyes of 10 myopic patients who had previously undergone photorefractive keratectomy (PRK) or phototherapeutic keratectomy (PTK) by excimer laser. RESULTS: Symptoms of visual loss in two eyes were initially attributed to corneal haze. In 10 of 11 eyes visualisation of the retinal detachment and causative break was possible despite mild corneal haze and optical aberrations caused by the refractive laser procedure. Retinal reattachment was achieved in all 11 eyes though one eye required four surgical interventions. CONCLUSION: This is the first published report to describe an association between retinal detachment and previous excimer laser treatment. The association would appear to reflect the predisposition of myopes to retinal detachment. Clinicians should be aware of potential retinal pathology in patients undergoing PRK.

Adult↗