Biomedical subjects
A Gaudric
Publications and source records attributed to A Gaudric.
Growth factors and diabetic retinopathy.
Preretinal neovascularization and chronic retinal oedema are the two major sight-threatening complications that can occur during diabetic retinopathy. Ocular neovascularization is strongly associated with retinal ischaemia, and growth factors have been implicated in its pathogenesis. The ischaemic retina is assumed to secrete growth factors that stimulate residual vessels to proliferate. Interest has focused on basic fibroblast growth factor (bFGF), insulin-like growth factor-1 (IGF-1), platelet-derived growth factor (PDGF), transforming growth factor beta (TGF beta) and more recently vascular endothelial cell growth factor (VEGF). Histologic studies have demonstrated the presence of growth factor proteins and receptors and/or their mRNA, mainly VEGF, PDGF, and bFGF, in preretinal membranes of patients with proliferative diabetic retinopathy. Elevated intravitreal levels of IGF-1 and VEGF correlating with neovascular activity have been found in some patients. However, a direct causal relationship between ischaemia, growth factors and neovascularization has not been clearly demonstrated despite considerable research work. To date, the growth factor correlating most closely with neovascularization is VEGF. As many growth factors seem to be produced during the neovascular process, their specific inhibition probably will have limited effects. Laser photocoagulation of the retina has proved beneficial for regression of new vessels, probably through destruction of the ischaemic retina producing neovascular growth factors, and is currently the only treatment for proliferative diabetic retinopathy. Inhibition of IGF-1 by somatostatin analogs has produced unsatisfactory results. Other vascular inhibitors are currently being studied.
[Recommendations of the ALFEDIAM (French Association for the Study of Diabetes and Metabolic Diseases) for the screening and surveillance of diabetic retinopathy].
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[Retinectomies in the treatment of retinal detachments with vitreoretinal proliferation].
PURPOSE: To investigate the anatomical and functional results of retinectomy in the treatment of complex retinal detachment. METHODS: We reviewed the files of 48 patients who underwent peripheral retinectomy of 90% or more for retinal detachment with anterior proliferative vitreoretinopathy stage A1 (6 cases), A2 (23 cases, A3 (11 cases) or A4 (8 cases). Retinotomy was performed when complete reattachment of the retina posterior to the buckling was not obtained despite careful dissection of the peripheral vitreoretinal contraction. Retinotomy was completed by excision of the anterior retinal flap. After perfluorocarbon liquid injection, laser retinopexy and perfluorocarbon-silicone exchange were performed. RESULTS: Silicone oil was removed from 46 eyes (96%). The retina remained attached in 37 eyes (77%) with a visual acuity of 1/20 or more in 19 of them. Functional results did not correlate with the size of the retinectomy. The major complications were retraction of the retinectomy edge and recurrence of proliferative vitreoretinopathy, responsible for anatomic failure in 9 of the 11 cases. Hypotony (i.e. intraocular pressure of 5 mmHg or less) only occurred in 6 of the 37 successful cases. CONCLUSION: Retinectomy is a useful surgical tool for eyes with advanced proliferative vitreoretinopathy when careful membrane dissection and encircling buckling seem to be insufficient to obtain retinal setting. Its success rate is good and leads to relatively few complaints.
[Evaluating the results of surgery of choroidal neovessels].
BACKGROUND: Subfoveal choroidal neovascularization has usually a poor visual prognosis. Submacular surgery has been advocated as an alternative treatment. Visual results of this recent surgical technique is under current clinical evaluation. METHODS: We retrospectively reviewed the charts of 16 eyes from 15 patients who underwent submacular surgery through a small retinotomy. Mean follow-up was 8 months (range from 5 to 88 weeks): group 1: submacular hemorrhages caused by age-related macular degeneration, 8 eyes; group 2: advanced subfoveal choroidal neovascularization in age-related macular degeneration, 3 eyes; group 3: young onset subfoveal choroidal neovascularization, 5 eyes. RESULTS: Group 1: mean preoperative visual acuity was 0.024. Postoperative visual acuity increased for 5 eyes (63%) and decreased for 3 eyes (37%) (mean follow-up: 33 weeks). Two eyes had recurrent neovascularization. Group 2: mean preoperative visual acuity was 0.083. Postoperative visual acuity decreased for both eyes (mean follow-up: 58 weeks). Two eyes had recurrent neovascularization. Group 3: mean preoperative visual acuity was 0.082. Postoperative visual acuity increased for both eyes (mean follow-up: 26 weeks). Two eyes had recurrent neovascularization. In both groups, recurrent neovascularization was managed by laser photocoagulation. CONCLUSIONS: Surgery of subfoveal choroidal neovascular membranes may stabilize or improve visual acuity in young patients. In subfoveal choroidal neovascularization due to age-related macular degeneration. this technique does not provide currently measurable visual improvement except in cases complicated by submacular hemorrhage. Results of future trials comparing surgery with spontaneous evolution or laser photocoagulation are necessary.
[Surgical treatment of post-traumatic macular holes].
BACKGROUND: Macular hole is a rare complication of blunt ocular trauma. Little is known about its spontaneous course and only a few operated cases have been reported. METHOD: We present five cases of post-traumatic macular holes, 4 of which have been operated on. RESULTS: In one case, the hole sealed spontaneously due to the formation of a slightly contractile epimacular membrane, and visual acuity improved from 0.1 to 0.5. The other four cases underwent vitrectomy, posterior hyaloid stripping, fluid-gas exchange and 12 days of postoperative positioning. In addition, two of these cases had autologous platelet injection. The macular hole closed in 3 of the 4 cases and vision improved in two. CONCLUSION: Traumatic macular holes can close spontaneously, although this is rare. Usually, surgery with or without healing adjuvants is needed to close the hole. Visual results may be good if there is no damage to the subfoveal retinal pigment epithelium or to Bruch's membrane.
[Results of surgery of vitreomacular traction syndromes].
PURPOSE: The vitreomacular traction syndrome is a rare entity in which partial posterior vitreous detachment is combined with persistent macular adherence, thus causing macular traction. In most cases, an epimacular membrane is associated with this vitreomacular traction. We evaluate here the results of vitreous surgery for this syndrome. METHODS: We reviewed 18 consecutive eyes that had undergone vitrectomy and posterior epiretinal membrane stripping, to define the visual results and complications of surgery for the vitreomacular traction syndrome. Minimum follow-up was 3 months. RESULTS: Patients' average age was 63.5 years. All had evidence of cystic macular changes on biomicroscopic examination. Sixteen patients had an epiretinal membrane, and two, a full-thickness macular hole. Cystoid macular edema was present in 7 eyes on fluorescein angiography. The release of vitreomacular traction improved vision in 72% of eyes, with six patients obtaining 20/40 visual acuity or better. Complications of surgery included progression of nuclear sclerosis, and epiretinal membrane formation. CONCLUSION: Vitrectomy for vitreomacular traction syndrome may improve visual acuity, but the visual prognosis remains poor.
[Macular epiretinal membrane and cataract].
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[Macular surgery].
Macular surgery has made great strides in the past few years, particularly to treat some age-related maculopathies. Epimacular membranes, which occur after posterior vitreous detachment, must be operated if they result in loss of visual acuity, metamorphopsia or disturbance of binocular vision. Visual improvement is obtained in more than 70% of the cases. Macular holes, which are related to a vitreous traction on the macula, can be closed surgically in 70 to 90% of the cases. Choroidal neovascularisation and submacular haemorrhages may be operated on when laser photocoagulation is impossible.
An aspirating forceps to remove the posterior hyaloid in the surgery of full-thickness macular holes.
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[Detection, monitoring and treatment of diabetic retinopathy. Recommendations of ALFEDIAM. Committee of above-mentioned experts and validated by the board of directors and scientific board of ALFEDIAM].
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[Surgery of macular holes].
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Acute posterior multifocal placoid pigment epitheliopathy after hepatitis B vaccine.
OBJECTIVE: To report two cases of acute posterior multifocal placoid pigment epitheliopathy after immunization with a recombinant hepatitis B virus vaccine. DESIGN: Case reports. RESULTS: Two patients had development of visual loss 3 days to 2 weeks after the booster administration of 20 micrograms of recombinant hepatitis B virus surface antigen (Engerix-B). In both cases, fundus examination, fluorescein angiograms, and the course of the disease were typical of acute posterior multifocal placoid pigment epitheliopathy. In case 1, 1 week after immunization, the leukocyte count was 10.3 X 10(9)/L with 24% polynuclear eosinophils (2.47 X 10(9)/L); in case 2, blood cell counts were normal. CONCLUSION: Hepatitis B virus immunization may be a risk factor for acute posterior multifocal placoid pigment epitheliopathy. Molecular mimicry between a retinal pigment epithelium protein and hepatitis B surface antigen could play a role. These cases suggest an immune-mediated retinal pigment epithelium disruption or choroidal vascular occlusions triggered by hepatitis B surface antigen.
Autologous platelet concentrate for the treatment of full-thickness macular holes.
BACKGROUND: To improve the anatomic success rate in the surgery of full-thickness macular holes, we tested, in a prospective pilot study, the effects of autologous platelet concentrate deposited on the macula at the end of surgery. METHODS: Two consecutive groups of patients were compared. Twenty eyes (group 1, mean symptom duration 11 months) were operated on with injection of an autologous platelet concentrate on the macula after fluid-gas exchange. Another 20 eyes (group 2, mean symptom duration 11 months) were subsequently operated on without autologous platelet concentrate. For all stage 3 holes, posterior hyaloid was detached en bloc at the level of the optic disc. The patient was left supine for 24 h after surgery, and then remained face down for 10 days. RESULTS: In group 1, 19 cases were an anatomic success, i.e. there was flattening of the retina surrounding the hole and reattachment of the edge of the hole to the retinal pigment epithelium; in 9 cases the hole was even undetectable. Final visual acuity was 0.5 or more in 9 eyes, and 0.4 or more in 14. Visual acuity improved by two lines or more in 17 of the 19 successfully operated eyes. In group 2, only 13 cases were an anatomic success. The functional results for the successfully operated eyes were identical to those of group 1. CONCLUSION: These results strongly suggested that autologous platelet concentrate could significantly improve the success rate in macular hole surgery and led us to begin a comparative, prospective, randomized trial.
Macular pattern dystrophy associated with a mutation of mitochondrial DNA.
PURPOSE/METHODS: To establish association of a macular pattern dystrophy with maternally inherited diabetes and deafness, a new subtype of diabetes mellitus caused by a mutation of mitochondrial DNA (mtDNA). Two probands of two different families with maternally inherited diabetes and deafness were examined. RESULTS/CONCLUSION: Both probands exhibited a macular pattern dystrophy, maternally inherited in one patient. The association of a macular pattern dystrophy with diabetes should lead to screening for a mutation of mtDNA.
[Occlusion of the central retinal vein and its branches. Etiology, diagnosis, course, prognosis, treatment].
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Spontaneous evolution and photocoagulation of diabetic cystoid macular edema.
Cystoid macular edema (CME) causes progressive visual impairment in diabetic patients and its treatment by photocoagulation remains unsatisfactory. We observed its spontaneous evolution for 3 years in 31 eyes. CME resolved in 9 eyes, was fluctuant in 16 and worsened in 7. Mean group visual acuity (VA) remained unchanged. Two modalities of photocoagulation were studied. In 27 eyes exhibiting CME combined with circinate exudates (group 1), extramacular focal photocoagulation was applied to the center of the exudates. Exudates disappeared from 23 eyes and CME from 12 eyes. Mean group VA remained unchanged. In 24 eyes with CME but without exudates (group 2), perifoveolar grid photocoagulation was applied over the CME area. CME disappeared from 15 eyes. Mean VA remained unchanged. These results show that CME with exudates requires a two-step treatment, comprising first focal photocoagulation, which clears exudates and often improves CME, and second--but only if CME persists and VA is below 0.5- perifoveolar grid photocoagulation, which often clears CME and stabilizes VA.
Contribution of scanning laser ophthalmoscopy to the functional investigation of subjects with macular holes.
A study was designed to validate a functional investigation performed with the scanning laser ophthalmoscope before surgery for macular holes in 12 eyes: The assessment included fundus examination, a functional examination resulting in evaluation of the preferred retinal lows, visual acuity and recording of visual evoked potentials. The preferred retinal locus was evaluated by presenting a small square area, and visual acuity was determined by means of calibrated figures. The visual evoked potentials were evoked by three alternating checkerboards (check size, 30', 2 Hz) centered over the hole and seen at an angle of 6.5 x 6.5 degrees, 2.5 x 2.5 degrees and 6.5 x 6.5 degrees with central exclusion of 2.5 x 2.5 degrees. The appearance of the fundus visualized by scanning laser ophthalmoscopy consisted of a clear central disk corresponding to the hole, surrounded by a very dark ring, associated with a second, less dark ring with unclear margins. Fixation was unstable in one case with a visual acuity of 20/70. In 11 cases, fixation was localized to the superior retina with a visual acuity superior to 20/70. The visual evoked potentials evoked by 6.5 x 6.5 degrees were discernible in all 12 eyes; visual evoked potential by annular stimuli were discernible in 11 cases. The 2.5 x 2.5 degrees stimulus evoked no response in eight cases, proving the area of the hole was nonfunctional. A response was recorded in the four other cases, where the dimension of the holes was less than 2 degrees. The results of this scanning laser ophthalmoscopic assessment demonstrated a precise evaluation of the residual macular function in the cases of full-thickness macular holes.