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P Hamard

Publications and source records attributed to P Hamard.

At least 19 recordsLinked to original sources
PubMed2002

Confocal microscopic examination of trabecular meshwork removed during ab externo trabeculectomy.

AIMS: The aim of the ab externo trabeculectomy (AET) is to remove the external portion of the trabecular meshwork (ETM) responsible for the main aqueous outflow resistance in glaucoma patients, with no opening of the anterior chamber. ETM characteristics were evaluated with a confocal microscope. METHODS: A prospective comparative observational case series was performed in 60 consecutive medically treated patients with primary open angle glaucoma and eight postmortem normal donors' eyes that underwent AET. Once deroofing the Schlemm' s canal (SC), a deeper dissection led to removal of a coherent membrane (ETM) which allowed satisfactory aqueous egress through the remaining intact internal trabecular meshwork (TM) layers. After fixation with acetone and immunostaining with anti-vimentin antibody, ETM were analysed with a confocal microscope. RESULTS: Glaucomatous ETM (mean thickness: 29.5 (7.6) micro m) were characterised by a severe paucicellularity compared with the controls (respectively 37.3 (9.7) cells/area and 167.5 (24.9) cells/area, p<10(-4)). ETM analysis showed involvement of both cribriform and corneoscleral layers. ETM cell density was significantly decreased in case of preoperative fluorometholone instillation. CONCLUSION: Paucicellularity of glaucomatous TM is confirmed by this original technique. Structural characteristics of the ETM, whose removal allows satisfactory aqueous egress, suggest that aqueous outflow resistance not only involves inner wall of SC and juxtacanalicular meshwork but also corneoscleral trabecular layers.

Adult↗
PubMed2002

[Non penetrating filtering surgery, evolution and results].

Trabeculectomy is currently the standard filtration procedure for glaucoma surgical treatment. Despite several advantages over full-thickness procedures, trabeculectomy can be responsible for early postoperative complications related to sudden ocular decompression that can lead to hypotony with its sight-threatening complications. Nonpenetrating glaucoma surgeries, namely viscocanalostomy and deep sclerectomy with external trabeculectomy, have been developed in recent years in order to improve the safety of conventional filtering procedures. The goal of these procedures is to reduce intraocular pressure (IOP) by enhancing the natural aqueous outflow channels, while reducing outflow resistance, attributed for 75% to the trabecular meshwork and for 25% to the outer wall of Schlemm's canal (SC) or tissue surrounding it. In these procedures, the anterior chamber is not opened so that complications related to full thickness procedures are mainly avoided. In the last few years, viscocanalostomy and deep sclerectomy with external trabeculectomy have become the most popular nonpenetrating filtering procedures. Both involve the removal of a deep scleral flap, the external wall of SC, and corneal stroma behind the anterior trabecula and Descemet membrane, thus creating a scleral lake. The aqueous humor leaves the anterior chamber through the intact trabeculodescemetic membrane and reaches the scleral lake, from where it will egress into different pathways. In viscocanalostomy, a high-molecular viscoelastic substance is injected into the ostia of the SC in order to enlarge the SC and its collector channels. In deep sclerectomy with external trabeculectomy, the main goal is to remove the inner wall of the SC and the adjacent trabecular layers involved in aqueous outflow resistance, while leaving the innermost trabecular layers intact so that the anterior chamber does not open during operation. Different surgical adjuvants designed to maintain the scleral lake open are commercially available. Retrospective and prospective published studies have reported similar midterm results with trabeculectomy and nonpenetrating filtering procedures in terms of IOP control, with fewer postoperative complications and better visual acuity recovery with the nonpenetrating procedures. This article reviews the current nonpenetrating surgical procedure techniques, their mechanism of action, and their outcome.

Filtering Surgery↗
PubMed2002

[Human trabecular cells and apoptosis: in vitro evaluation of the effect of betaxolol with or without preservative].

PURPOSE: Trabecular meshwork, which is involved in aqueous outflow resistance, is deeply modified in glaucoma patients, with a decrease in the trabecular cell number. Trabecular toxicity of antiglaucoma medications cannot be excluded. On a human cultured trabecular cell line, we investigated the potential proapoptotic effect of a beta-blocker with or without preservative, benzalkonium chloride (0.01% BAC), by flow cytometry and confocal microscopy. MATERIAL: and METHODS: A human immortalized trabecular cell line (HTM-5) obtained from a normal donor was cultured under normal conditions. Preserved 0.25% betaxolol suspension (betaxolol BAC +), unpreserved 0.25% betaxolol suspension, and 0.01% BAC were respectively added to the culture medium in a 1/10 or 1/100 dilution for 15 minutes. After a 24-hour recovery period in normal culture conditions, cell size and the expression of an apoptotic marker, Apo 2.7, were evaluated by flow cytometry and confocal microscopy. Untreated trabecular cells were used as control cells. RESULTS: Preserved and unpreserved betaxolol in a 1/10 dilution induced a significant decrease in trabecular cell size compared to controls. However, this cell size decrease was less pronounced than that induced by BAC at the same dilution. Similar results were obtained with betaxolol and BAC in a 1/100 dilution. Trabecular cell Apo 2.7 expression was significantly increased after treatment with betaxolol BAC + and BAC- in a 1/10 dilution compared to controls (36.8%, 28.1%, and 15.4%, respectively p<0.005). However, this proapoptotic activity was much less pronounced than that induced by BAC- at the same dilution (96.9%, p<10(-4)). Unpreserved betaxolol in a 1/100 dilution had no apoptotic activity on trabecular cells. Trabecular cell Apo 2.7 expression slightly increased with betaxolol BAC + at a 1/100 dilution (24.9%, p=0.04), while it was greatly increased with BAC at the same dilution (39.9%; p<10(-4)). CONCLUSION: In our model, unpreserved betaxolol at a low concentration displayed no proapoptotic activity on trabecular cells. On the other hand, preserved betaxolol displayed a moderate proapoptotic activity by triggering cell death of around 25% of cells. Trabecular cell toxicity appeared to be mainly due to the preservative benzalkonium chloride (BAC). Taken together, our results demonstrated that the strong apoptotic activity of BAC was greatly reduced within the preserved eye drops, probably through the interaction of BAC with the active compound.

Adrenergic beta-Antagonists↗
PubMed2001

[Evaluation of confocal microscopy in the analysis of the external trabecular membrane during deep nonpenetrating sclerectomy].

PURPOSE: Deep non penetrating sclerectomy (DNPS) is a new filtering surgical procedure whose aim is a selective ablation of the external portion of the trabecular meshwork (TM) which is involved in the aqueous outflow resistance, i.e. the inner wall of Schlemm's canal (SC) and the external trabecular layers, especially the cribriform TM. We evaluated, with a confocal microscope, the structural characteristics of this part of the TM in glaucomatous patients. METHODS: Thirty-six external trabecular membranes (ETM) were obtained from 33 consecutive glaucomatous patients (mean age: 56.5+/-14.5 years) and from four post-mortem normal donors (60.5 +/-7.7 years), which underwent DNPS according to the same surgical procedure. Under conjunctival and scleral flaps, the roof of the SC was opened and removed. A deeper dissection led to the removal of the inner wall of the SC and the adjacent ETM, i.e the TEM, which allowed a satisfactory aqueous flow through the remaining internal TM layers. After fixation with acetone or triton X100 and immunostaining with anti-fibronectin or vimentin antibodies, the samples were analyzed with a confocal microscope (Nikon EZ 2000). RESULTS: The mean thickness of the ETM was 34.4+/-7.3 microm in glaucomatous eyes, not significantly different from the controls (39.0+/-10.7 microm). The main characteristic of the glaucomatous ETM membrane is a paucicellularity as compared to the controls (respectively 21.6+/-12.1 cells/area and 156.1+/-28.8 cells/area). The confocal microscope analysis shows that the ETM involves two different portions of the trabecular meshwork. The architectural characteristics of the outermost portion of the ETM with its star-shaped cells arranged in a homogenous extra-cellular matrix, suggest that it is the trabecular cribriform meshwork. The inner portion of the ETM shows cells arranged regularly in a fibrillar extra-cellular matrix as described in the corneoscleral trabecular meshwork. CONCLUSION: These results confirm the previous reported histopathological changes of the glaucomatous TM. The thickness of the removed ETM and its structural characteristics show that the ablation of the TM layers necessary to obtain a satisfactory aqueous filtration, not only involves the cribriform layers but also one of the inner parts of the TM, i.e. the corneoscleral TM. This result suggests that aqueous humor resistance not only involves the cribriform trabecular meshwork but also a part of the corneoscleral trabecular meshwork.

Aged↗
PubMed2001

[An observational, retrospective two-year cost study in primary open-angle glaucoma and ocular hypertension in newly diagnosed patients].

PURPOSE: To investigate the different treatment strategies in France and the direct costs for patients with newly diagnosed primary open-angle glaucoma or ocular hypertension who have started treatment with beta-blockers, and to estimate the total direct cost for two years of treat. MATERIAL: and methods: We analyzed 225 medical charts retrospective in eleven academically and office-based centers in France over the first two years after diagnosis. Standard costs for each resource in current medical practice were determined from the French Social Security perspective. RESULTS: The vast majority of patients (90%) had a diagnosis of primary, open-angle glaucoma or ocular hypertension in both eyes. In 60% of the patients we found a moderate or severe defect in their visual field or optic nerve. Intraocular pressure before treatment was 23.9+4.7mmHg and 17.5+4.2mmHg after two years of treatment. Over the first two years, 25% of visits led to a change in therapy (medical or surgical), involving 64% of the patients. Two-thirds of the changes occurred during the first year of treatment and in around 80% of cases for low intraocular pressure at check-up. Laser surgery or surgical intervention was performed in 25% of the patients. Total direct costs for two years were 5698F.F. The intraocular pressure before treatment was positively correlated (p<0.01) with treatment costs, while the initial intraocular pressure-lowering effects of treatment were negatively correlated with two-year costs. CONCLUSION: After two years of treatment, the mean intraocular pressure decreased from 24 to 17.5mmHg. The higher the basal intraocular pressures is, the more intensive the treatment and the higher the costs. The more efficient the treatment to decrease baseline intraocular pressure is, the earlier the costs will be reduced.

Aged↗
PubMed2001

[Prognostic outcome of leaking filtering blebs reconstruction with rotational conjunctival flaps].

PURPOSE: Late bleb leaks may follow months to years after filtering surgery especially with the use of antimetabolites. Complications related to beb leaks may lead to a decrease in visual acuity through complicated hypotony or ocular infection. Our retrospective study reports the anatomical and functional results of bleb reconstruction involving the resection of the bleb associated with the covering of the trabeculectomy site with a rotational conjunctival flap. MATERIAL: and methods: Twelve eyes of eleven patients with filtering bleb leaks occurring 3 months to 5 years after successful trabeculectomy (58.3% with adjunct of antimetabolites) underwent bleb surgical reconstruction between november 1995 and June 1999 and were followed until March 2000. Surgical bleb reconstruction was indicated because of persistent or a recurring bleb leak despite conservative medical treatment and blood bleb injections in seven cases. Complications associated with bleb leaks were chronical hypotony (9 cases), athalamy (1 case), hypotony maculopathy (1 case), and endophtalmitis with athalamy (1 case). Three patients had normal IOP but a bleb leak responsible for epiphora. All eyes were treated surgically through bleb excision and conjunctival closure was performed by rotational conjunctival flap. RESULTS: Mean (+/- SD) preoperative IOP was 5.1+/-3.5mmHg (range: 2 to 14mmHg). Mean (+/- SD) postoperative IOP evaluated before any other operation for uncontrolled IOP was 12.7+/-3.1mmHg (range: 6 to 15mmHg). Mean follow-up was 26.7+/-16.9 months (range: 9 to 64 months). All the complications related to the bleb leak resolved after bleb reconstruction. Surgery definively stopped the leak in 10 cases (83.3%) and allowed IOP control without treatment in 50.0% of the cases. Chronic recurring bleb leaks without hypotony occurred in two eyes and required surgery with conjunctival graft which led to a refractory increase in IOP responsible for loss of vision in one case. CONCLUSION: Bleb resection associated with the covering of the trabeculectomy site with a rotational conjunctival flap is a safe and effective procedure for the treatment of a late bleb leak and its complications. In most of the cases (83.3%), long-term IOP control can be expected without, medical treatment in 50% of the cases. Patients must be aware of the possibility of a recurring Seidel; however, the incidence of this complication remains low.

Adult↗
PubMed2001

[Acute ischemic optical neuropathy which became bilateral in 3 days in Horton disease].

We report a case of a 71-year-old man with sequential visual loss within 3 days due to giant cell arteritis confirmed by a temporal artery biopsy. The anterior ischemic optic neuropathy was associated with cilioretinal artery occlusion on the right eye. He improved after intravenous corticosteroid therapy. Clinical characteristics and treatment are discussed.

Acute Disease↗
PubMed2000

Spatial distributions of expansion rate, cell division rate and cell size in maize leaves: a synthesis of the effects of soil water status, evaporative demand and temperature.

The spatial distributions of leaf expansion rate, cell division rate and cell size was examined under contrasting soil water conditions, evaporative demands and temperatures in a series of experiments carried out in either constant or naturally fluctuating conditions. They were examined in the epidermis and all leaf tissues. (1) Meristem temperature affected relative elongation rate by a constant ratio at all positions in the leaf. If expressed per unit thermal time, the distribution of relative expansion rate was independent of temperature and was similar in all experiments with low evaporative demand and no water deficit. This provides a reference distribution, characteristic of the studied genotype, to which any distribution in stressed plants can be compared. (2) Evaporative demand and soil water deficit affected independently the distribution of relative elongation rate and had near-additive effects. For a given stress, a nearly constant difference was observed, at all positions of the leaf, between the relative elongation rates of stressed plants and those of control plants. This caused a reduction in the length of the zone with tissue elongation. (3) Methods for calculating cell division rate in the epidermis and in all leaf tissues are proposed and discussed. In control plants, the zone with cell division was 30 mm and 60 mm long in the epidermis and in whole tissues, respectively. Both this length and relative division rate were reduced by soil water deficit. The size of epidermal and of mesophyll cells was nearly unaffected in the leaf zone with both cell division and tissue expansion, suggesting that water deficit affects tissue expansion rate and cell division rate to the same extent. Conversely, cell size of epidermis and mesophyll were reduced by water deficit in mature parts of the leaf.

Cell Division↗
PubMed2000

[Consensus on neovascular glaucoma].

Neovascular glaucoma is a dreadful pathology with a rapid spontaneous evolution responsible for painful and blind eye. The main cause is an anterior neovascular proliferation following a broad retinal ischemia. Early diagnosis and treatment are required in order to maintain a good visual status and a satisfactory IOP control with medical, surgical or cylodestructive procedures. In any case, the treatment of the retinal ischemia has to be performed. One must keep in mind that the most efficient way to avoid the incidence of neovascular glaucoma is a strict control of clinical situations potentially responsible for retinal ischemia, namely VRO in elderly patients and diabetic retinopathy in younger patients.

Adult↗
PubMed2000

[What strategy after three trabeculectomy failures?].

Three trabeculectomy failures raises the delicate problem of refractory glaucoma with unresponsive ocular hypertony. The therapeutic strategy requires first a careful assessment of the reasons for the previous failures (internal or external obstacles to filtration which might have responded to preventive treatment), then, depending on the patient's age, type of glaucoma, anatomic status of the ocular structures and the visual potential of the eye, a choice has to be made between different surgical techniques aimed at favoring aqueous humor evacuation (trabeculectomy associated with antimetabolites or drainage implant) or destruction of the ciliary body to reduce intraocular pressure by limiting the production of aqueous humor. Choosing between these two possibilities is not an easy task as success rates are highly variable on such eyes and complications are frequent, leading to lower visual acuity in 30 % of the cases. These salvage procedures recall that first line trabeculectomy must be optimized in all cases.

Glaucoma↗
PubMed2000

[Trans-scleral diode laser cyclophotocoagulation for the treatment of refractory pediatric glaucoma].

PURPOSE: To evaluate the success rate of contact diode transscleral cyclophotocoagulation (TSCPC) in pediatric refractory glaucoma. PATIENTS: and method: Twenty-eight eyes of 28 patients (age range 5 months to 26 years) with medical and surgical refractory pediatric glaucoma due to primary congenital glaucoma (group 1, 20 eyes) or aphakic congenital glaucoma (group 2: 8 eyes), were included in this retrospective study. All eyes underwent one or more TSCPC with the diode laser (Oculight SLX, Iris Medical) with a minimal follow-up of 2 months. Success was defined as intraocular pressure (IOP) between 6 and 20 mmHg after one or more procedures, with no increase in medical hypotensive therapy, and no progression to another hypotensive procedure. RESULTS: Mean baseline IOP was 29.4 +/- 7.8 mmHg (range 25 to 60 mmHg) and mean follow-up was 10.3 +/- 6.9 months (range 2 to 26 months). Success rates evaluated at 6 and 12 months (Kaplan Meier survival curves) were 54.4% and 27.7% respectively, with one-third of the eyes retreated once or more. These success rates were similar in both groups with a mean baseline IOP decrease of 38.9 +/- 15.9%. Postoperative uncontrolled hypertony occurred in the first 3 months in 6 (21.4%) eyes, leading to surgical IOP management. Other complications were decrease in visual acuity (14.3%), inflammation (25.5%) and phthisis (3.5%). CONCLUSION: TSCPC with the diode laser is a disappointing procedure for the management of refractory pediatric glaucoma, with poor mid-term IOP control and high incidence of complications including severe uncontrolled IOP increase. For these reasons, this cyclodestructive procedure should be considered as a last resort therapy for patients with refractory pediatric glaucoma.

Adolescent↗
PubMed2000

["Idiopathic" acute optic neuropathies in children].

We reported a retrospective study of 27 children (mean age = 10 years), who presented a loss of vision due to an acute optic neuritis, between 1982 and 1997. The symptoms ar more likely bilateral in children, and frequently associated with systemic viral infection or hepatitis B vaccination. Multiple sclerosis occurs approximately in 20 p. cent of the cases, i.e. less frequently than by adults. Magnetic resonance imaging is now systematic: in 20 children hyperintense nodular abnormalities in a various distribution was demonstrated by 9 children. During the follow-up, 23 eyes of 27 have an excellent recovery of vision, but 4 patients have developed multiple sclerosis. Corticotherapy was uses in 23 cases, in the form of methylprednisolone intravenous flashes in 14 cases.

Acute Disease↗
PubMed1999

[Deep nonpenetrating sclerectomy and open angle glaucoma. Intermediate results from the first operated patients].

PURPOSE: The aim of this retropective study is to evaluate and to compare in glaucoma patients, the mid-term results of the non penetrating deep-sclerectomy (NPDS) with collagen implant or with per operative application of 5 fluorouracile (5 FU). MATERIAL AND METHODS: The aim of the NPDS, a new filtering surgical procedure, is to remove under a scleral flap the Schlemm's canal and the juxtacanalicular trabecular meshwork responsible for the outflow resistance in order to obtain a sub-conjunctival filtration of the aqueous humor with no opening of the anterior chamber. Forty-two open angle glaucoma patients with uncontrolled intra-ocular pressure and with no risk factor of bleb fibrosis, underwent a NPDS. In 27 eyes (group 1) a sponge soaked with 5 FU (50 mg/ml) was applied for 5 minutes in the scleral bed, and in 15 eyes (group-2) a collagen implant (Staar*) was sutured in the scleral bed. A complete ophthalmologic examination was performed on days 1, 8, months 1,2,3 and each 3 months until the end of the follow-up. In case of increased IOP, goniopuncture with the Nd: YAG laser was performed at any time of the post operative period. RESULTS: The mean intra-ocular pressure (IOP) significantly decreased from 23.5 +/- 5.1 mmHg to 15.5 +/- 2.9 at 11.1 +/- 5.6 months follow-up (group 1, p < 10(-3)) and from 22.6 +/- 6.9 Hg to 16.2 +/- 3.9 mmHg at 8.8, 3.6 months follow-up (group 2, p < 10(-3)) with a significant decrease in the medical treatment (p < 10(-3)). The Kaplan Meier probability of success (IOP < or = 20 mmHg without treatment and with no visual field deterioration) at 6 and 12 months was similar in both groups: 57.3% (group 1) and 66.0% (group 2) with a mean decrease in IOP of 30%. Goniopuncture had to be performed in more than one third of case in each group and was effective to control the IOP in half of the cases. No complication related to hypotony or inflammation occured in the post operative period. CONCLUSION: NPDS is an interesting alternative to the classical trabeculectomy since the post operative complications are markedly reduced. However, the mid-term control in IOP appears to be slightly lower. The use of a collagen device does not lead to better control in IOP as compared to the use of a sponge of 5 FU.

Administration, Topical↗
PubMed1998

Migraine and glaucoma: an epidemiologic survey of French ophthalmologists.

Glaucoma is a common ocular disorder; a high intraocular pressure is observed in the majority of glaucoma (HIOPG) cases, but some patients have low-tension glaucoma (LTG). In the literature, some works link LTG and migraine, which is speculative of a potential role of a vasospastic factor or diathesis common to migraine and LTG. Using a standardized questionnaire based on International Headache Society (IHS) criteria, we investigated 954 glaucoma patients; 320 (33.5%) described a headache (migraine or tension-type headache) and 240 (25.1%) presented the IHS criteria for migraine. Migraine prevalence was not significantly different between HIOPG and LTG patients (22.8% and 32%, respectively) in this study.

Aged↗
PubMed1998

[Evaluation of the Humphrey perimetry programs SITA Standard and SITA Fast in normal probands and patients with glaucoma].

PURPOSE: To evaluate the new threshold strategies of the Humphrey Field Analyser, SITA Standard and SITA Fast, in normals and glaucoma patients. METHODS: Fifty healthy volunteers and 50 glaucoma patients were tested twice with three algorithms: Full Threshold, SITA Standard and SITA Fast in two sessions. The second test was taken into account to eliminate learning effect. Glaucoma patients were chosen to cover a large range of deficits. Quantitative analysis of global indexes was performed as well as qualitative comparison of visual fields by a trained optometrist. RESULTS: Compared to Full Threshold, testing time was reduced by 51% in normals and 49% in glaucoma with SITA Standard and by 72% and 69% with SITA Fast, respectively. In glaucoma, mean testing time dropped from 16'01" with Full Threshold to 8'05" with SITA Standard and to 4'55" with SITA Fast. Quantitative comparison showed a high correlation between indexes (MD Full Threshold vs MD SITA Standard: r = 0.98, p < 0.01; PSD Full Threshold vs PSD SITA Standard: r = 0.94, p < 0.01). However SITA Standard and SITA Fast had a tendency to underestimate visual field defects. In glaucomatous subjects, mean MD ameliorated by 1.01 dB with SITA Standard and by 1.71 dB with SITA Fast. Mean PSD ameliorated by 0.04 dB and 0.43 dB, respectively. Qualitative analysis confirmed these last results showing artificial slight or important improvement of visual fields in 21% of the cases with SITA Standard and 30% with SITA Fast, compared to Full Threshold. CONCLUSION: SITA Standard and SITA Fast strategies improve dramatically visual field testing time, by 51% and 72% respectively. However, one should be cautious in comparing results obtained with different algorithms, as these new strategies improve the mean defect and, to a lesser extent, the localized defect.

Adult↗
PubMed1997

Genetic heterogeneity of primary open angle glaucoma and ocular hypertension: linkage to GLC1A associated with an increased risk of severe glaucomatous optic neuropathy.

The GLC1A locus for autosomal dominant juvenile and middle age onset primary open angle glaucoma (OAG) has been mapped to chromosome 1q21-q31. OAG, however, is a heterogeneous disease. We tested linkage of OAG and ocular hypertension (OHT), a major risk factor for OAG, to GLC1A in eight French families with multiple cases of juvenile and middle age onset OAG. There was strong evidence of genetic heterogeneity, four families being linked to GLC1A and two or three others being unlinked, depending on whether the complete OAG phenotype was analysed alone or jointly with OHT. Peak intraocular pressure (IOP) did not differ significantly between the two groups of families, while linkage to GLC1A conferred a highly increased risk of developing OAG and of having severe glaucomatous optic neuropathy. Testing linkage of familial OAG to GLC1A may therefore have prognostic value too.

Adult↗