Wastewater reuse in agriculture is a widespread practice in developing countries, especially in urban areas where water shortage and poverty encourage people to use that marginal resource. Raw or treated wastewaters are used by farmers, but even treated wastewaters frequently do not meet WHO and FAO standards for irrigation water. Such practices may lead to health hazards, relatively well documented in the literature and to environmental damages. Adverse environmental impacts such as soil degradation and groundwater contamination are frequently associated with the use of wastewater from industrial sources. Previous studies have demonstrated that wastewater irrigation may decrease soil hydraulic conductivity and infiltration rate. Nevertheless, the effects on soil structural and chemical behaviors have been little studied so far and need further investigations.The impacts of irrigation with alkaline and sodic industrial wastewater previously treated in microphyte ponds on soil physical and chemical properties were studied downstream the sewage treatment plant of Kossodo in Ouagadougou, on plots cropped with eggplants. Plots irrigated with fresh water and non cropped, non irrigated plots were used as controls.Different soil properties were characterized: pore volumes determined by using shrinkage analysis, pH and electrical conductivity of water extracts, and major soluble and exchangeable cations (Ca, Mg, K, and Na). Organic matter characterization was performed by means of three dimensional fluorescence spectra analysis to determine its origin and evolution on irrigated soils.Plots irrigated with wastewater showed important structural damages, especially in the subsurface horizon where the soil pore network collapsed dramatically, resulting in a compact impermeable layer. Fluorescence spectra revealed that the organic matter contained in the wastewater was largely dissolved due to a sharp soil pH increase, resulting in black alkali formation at the surface: the soil became sodic, with an exchange complex dominated by sodium, whereas plots irrigated with fresh water kept properties comparable to that of non irrigated plots. Such a rapid soil sodication was seldom reported so far. The study emphasizes the need to carefully examine irrigation water quality and particularly calcite residual alkalinity and suggests that shrinkage analysis could be used to monitor the physical changes of soil properties upon sodication. Inadequate wastewater quality is likely to cause deep and irreversible damages to irrigated soils. (C) 2013 Elsevier B.V. All rights reserved.

The scarcity of freshwater resources is a critical problem in semi-arid zones and marginal quality water is increasingly being used in agriculture. This paper aimed at evaluating the physico-chemical and biological risks on irrigated soils and fruits of macrophyte treated wastewater (TWW), the nutrients supply, and the effect on tomato and eggplant production in semi-arid Burkina Faso. During three years of experiments, treated wastewater was used, with fresh water as control, in combination with or without mineral fertilizer application at recommended rate (140 kg N/ha + 180 kg P2O5/ha + 180 kg K2O/ha). The study revealed that the treated wastewater provided variable nutrients supply depending on year and element. The treated wastewater without mineral fertilizer improved eggplant yield (40% in average) compared to the freshwater. Both crops responded better to mineral fertilizer (52% for tomato and 82% for eggplant) and the effects of the treated wastewater and fertilizer were additive. As the N supply of TWW was very unsteady (8-227% of crop need), and P2O5 supply did not satisfy in whole crop need (3-58%) during any of the three years of experiment, we recommended that moderate N and P2O5 fertilizers be applied when irrigating with TWW in semi-arid West-Africa. On the contrary, the K2O supply was more steady and close to crop requirement (78-126%) over the three years of experiment and no addition of K fertilizer may be needed when irrigated with TWW. Faecal coliforms and helminth eggs were observed in treated wastewater and irrigated soils at rate over the FAO and WHO recommended limits for vegetable to be eaten uncooked. Tomato fruits were observed to be faecal coliform contaminated with the direct on-foliage irrigation with treated wastewater. Our results indicate that treated wastewater can effectively be used as both nutrients source and crop water supply in market gardening in the semi-arid Sub-Saharan West Africa (SSWA) where freshwater and farm income are limiting. Yet consumers should properly cook or disinfect treated-wastewater irrigated vegetables before eating, and market gardeners should also be careful manipulating treated wastewater to avoid direct health contamination in this environment. (c) 2010 Elsevier B.V. All rights reserved.

BACKGROUND:Besides antimetabolites (5-fluorouracil [5-FU]), cytostatic agents (mitomycin C [MMC]) and topical steroids, various substances have been used for the modulation of wound healing in filtering glaucoma surgery. The anti-inflammatory effects of hyaluronic acid and its space-occupying properties may be useful in filtering as well as in non-filtering glaucoma surgery.PATIENTS AND METHODS:In a non-randomised pilot study cross-linking hyaluronic acid (HealaFlow) was injected below the scleral flap and under the conjunctiva in 66 patients undergoing filtering surgery. All 66 patients (age 70.3 +/- 9.6 years; 41 - 88) had a standard trabeculectomy with MMC (0.25 % for 3 min). Glaucoma diagnoses were pseudoexfoliation glaucoma in 32 cases, primary open-angle glaucoma in 32 cases, ICE syndrome in one case and Axenfeld/Rieger in one case.RESULTS:Intraocular pressure (IOP) levels were reduced from preoperatively 22.3 +/- 6.0 mmHg (12 - 40) with 2.7 +/- 1.0 (1 - 4) IOP-lowering medications to 11.9 +/- 5.1 mmHg (2 - 26) after 29.8 +/- 12.4 weeks (13 - 56) follow-up. Fifty-nine of the 66 patients (89.4 %) did not need IOP lowering medications at the end of the follow-up, 52 / 66 patients (78.8 %) had an IOP < or = 14 mmHg, 47 of these 52 patients (90.4 %) without medication. Argon laser suturolysis had to be performed in 28 / 66 eyes (42.4 %), 40 / 66 patients (60.6 %) required 1 - 4 subconjunctival injections of 15 mg (0.3 mL) 5-fluorouracil.CONCLUSIONS:Injections of HealaFlow below the scleral flap and the conjunctiva at the end of the surgery along with intraoperative application of MMC showed promising IOP-lowering effects in trabeculectomy. A prospective randomised study is required to confirm these preliminary results.

PURPOSE:To compare the intraocular pressure (IOP) diurnal fluctuations of glaucoma patients treated with latanoprost 0.005% once a day with patients with controlled IOP after deep sclerectomy or trabeculectomy.METHODS:The trial included 60 prospectively recruited subjects with primary open-angle glaucoma. The medical group consisted of 20 patients with controlled IOP (<18 mm Hg) under latanoprost 0.005% monotherapy and with no history of previous intraocular surgery or argon laser trabeculoplasty; the surgical groups included 20 patients after trabeculectomy, and 20 patients after deep sclerectomy with collagen implant (DSCI). The patients in the surgical groups had a controlled IOP without any ocular hypotensive medications. All patients underwent a diurnal tension curve (08:00-17:00/three-hour intervals), followed by a water-drinking test (WDT) with the last IOP measurement taken at 21:00 hours. The between-group differences were tested for significance by means of analysis of variance (ANOVA).RESULTS:Baseline IOP was significantly different between the trabeculectomy group (10.1 mm Hg (3.4 SD)), the DSCI group (13.9 mm Hg (2.8)) and the latanoprost group (15.5 mm Hg (2.0); p = 0.005). The average IOP during the diurnal tension curve (10.1, 13.7, and 15.7 mm Hg, respectively, for the trabeculectomy, DSCI, and latanoprost groups) differed significantly between groups (ANOVA; p<0.0001), but the variation was comparable in the three groups (ANOVA; p = 0.13). After the WDT, elevation of IOP was significantly greater among patients treated with latanoprost (p = 0.003).CONCLUSION:Trabeculectomy patients had a statistically significant lower average IOP in the diurnal tension curve compared with the other two groups. No wider variation in diurnal IOP with latanoprost compared with the surgical procedures was found. The IOP increase during the WDT was most marked in patients under latanoprost therapy.

Classical trabeculectomy is affected by numerous and serious drawbacks that have led to the development of nonpenetrating surgery. In this new filtering technique, the aqueous outflow through the juxtacanalicular trabeculum and Schlemm's canal is selectively increased without penetrating the anterior chamber. This is best performed by means of a careful and precise dissection of the outflow resistance pathway and by removing its most resistant portion. This requires both mastery of the microdissection technique and high-precision surgical tools. Finally, sound knowledge of the morphological features of such delicate structures is of paramount importance to avoid intra- and postoperative complications.

PURPOSE:To determine the absorption and the release of mitomycin-C from a collagen implant and tissue impregnation in the anterior structures of the rabbit eye.METHODS:Determining the quantity of mitomycin-C that a collagen implant can absorb with the difference between dry and soaked weight. Mitomycin-C release was measured in vitro using spectrophotometry. The measurement was repeated using a bioassay. Ocular tissue impregnation was determined in 12 eyes of six rabbits. Sclera, implant, aqueous, and ciliary body specimens were collected for concentration measurement using HPLC from 1 to 6 h after surgery.RESULTS:The mean mitomycin-C quantity absorbed in the implant was 3.22+/-0.2 microg. In vitro release was 0.13 mg/ml after 10 min and 0.05 microg/ml at 6 h. The bioassay showed almost no antifibrotic activity in sclera. In vivo release of mitomycin-C was high from the first to the sixth hour.CONCLUSION:After filtering surgery, mitomycin-C in the collagen implant is clearly released and ocular tissues are effectively impregnated.

The aqueous leaves the anterior segment via two different pathways, the classical and the uveoscleral routes. The main resistance to aqueous egress lies at the level of the juxtacanalicular trabeculum and the inner wall of Schlemm's canal. Impaired function of either one of these structures leads to a decrease in the outflow facility which eventually results in a significant increase in intraocular pressure. Success of non-penetrating surgery lies in the physical removal of these resisting elements without compromising of the structural integrity of the eye, thus preventing a sudden drop in the intraocular pressure. The selective filtration through the trabeculodescemetic membrane, the evacuation of the aqueous in the intrascleral space, the subconjunctival bleb and the subchoroidal space, and the final drainage into collector channels and drain veins are the key elements for a successful deep sclerectomy.

The nonpenetrating filtering procedure requires a functioning intrascleral space. This space is created after a careful dissection and resection of the deep scleral flap. In order to prevent a collapse of the remaining superficial flap that forms the roof of the intrascleral cavity, a space maintainer is usually inserted at this stage of surgery. Two different types of drainage devices are used: absorbable and nonabsorbable implants. The first type is currently made of porcine collagen material that is slowly absorbed over time, whereas the second is usually made of nondegradable materials that permanently remain in the scleral bed. No significant differences in the surgical technique can be found between the two types of implant. The long-term results are fairly similar for both of them, the absorbable implant being slightly more advantageous.

Purpose: To determine the absorption and the release of mitomycin-C from a collagen implant and tissue impregnation in the anterior structures of the rabbit eye.Methods: Determining the quantity of mitomycin-C that a collagen implant can absorb with the difference between dry and soaked weight. Mitomycin-C release was measured in vitro using spectrophotometry. The measurement was repeated using a bioassay. Ocular tissue impregnation was determined in 12 eyes of six rabbits. Sclera, implant, aqueous, and ciliary body specimens were collected for concentration measurement using HPLC from 1 to 6 h after surgery.Results: The mean mitomycin-C quantity absorbed in the implant was 3.22 +/- 0.2 mu g. In vitro release was 0.13 mg/ml after 10 min and 0.05 mu g/ml at 6 h. The bioassay showed almost no antifibrotic activity in sclera. In vivo release of mitomycin-C was high from the first to the sixth hour.Conclusion: After filtering surgery, mitomycin-C in the collagen implant is clearly released and ocular tissues are effectively impregnated.

The nonpenetrating filtering procedure requires a functioning intrascleral space. This space is created after a careful dissection and resection of the deep scleral flap. In order to prevent a collapse of the remaining superficial flap that forms the roof of the intrascleral cavity, a space maintainer is usually inserted at this stage of surgery. Two different types of drainage devices are used: absorbable and nonabsorbable implants. The first type is currently made of porcine collagen material that is slowly absorbed over time, whereas the second is usually made of nondegradable materials that permanently remain in the scleral bed. No significant differences in the surgical technique can be found between the two types of implant. The long-term results are fairly similar for both of them, the absorbable implant being slightly more advantageous.

An accurate determination of the soil hydraulic functions is crucial for using soil water simulation models. The purpose of this study is to compare different methods to estimate hydraulic properties and their effects on the simulation of soil water movement. Soil water retention and hydraulic conductivity functions were either measured in the laboratory (core method) and in the field (instantaneous profile method and crust method) or estimated from other soil properties (pedo-transfer functions, PTFs). The data were fitted to the van Genuchten equations and the resulting parameter sets were used as input of the mechanistic WAVE model to simulate soil water flow. Calculated and observed water content values were compared to assess the different methods used for determining the soil hydraulic properties.The hydraulic parameter sets generated from the different approaches were found to be significantly different and to have a strong impact on the soil water flow simulation. Soil water retention data obtained from field experiments and laboratory tests differ significantly near saturation but are similar for lower water content values. On the whole, retention curves given by the Rawls and Vereecken PTFs perform best while the other tested PTFs give poorer results. Unsaturated hydraulic functions given by the Saxton, Cosby and Rawls PTFs are relatively close to the measured data in the silt loam layers while the Vereecken PTF leads to good estimations in the pressure head mid-range values, but poor results in the high and low ranges. In the sandy loam layer characterized by low clay and organic matter content, all the tested PTFs perform very poorly. Globally, when considering prediction of both soil hydraulic functions, the Rawls PTFs were found to be the most adequate.The comparison between observed and simulated soil water content values indicates that the best agreement is achieved with hydraulic properties estimated from field experiments. Results are less satisfactory with the parameter sets obtained from the laboratory tests and very poor with the parameter sets given by the Rawls PTFs. (c) 2005 Elsevier B.V. All rights reserved.

Fast, simple, safe, efficient? In the past 5 years, the Ex-PRESS drainage device has been mentioned in the discussions of glaucoma surgeons. Its place in the surgical management of glaucoma has not been clear so far and much contradictory information and controversy have been circulated. In this issue of the BJO (p 425) is presented the first written clinical report on the Ex-PRESS tube used in combined cataract and glaucoma surgery. Glaucoma drainage devices (GDDs) were first introduced a century ago. Much experience has been gained in the use of these devices, and has led to many modifications in design, construction, and implantation techniques.1 In 1969 Molteno launched the concept of a tube and plate for glaucoma drainage, in which the plate is secured onto the episclera, helping with the formation of a posterior orbital filtering bleb.2,3 Contemporary GDDs, which dominate the market are the Molteno, Krupin, Baerveldt, Ahmed, and OptiMed devices, which all share the essential design concept of posterior filtration via a tube (outer diameter 0.56–0.63 mm) from the anterior chamber to a plate element secured to the episclera; they differ in plate design and size (135–500 mm2) and their provision for a …

Computer simulation of complex biological structures such as the human eye by finite element model enables us to develop a model of the outflow facility components that play a key role in the dynam...

Field experiments were performed on the site of Kamboinsé (Burkina Faso) to study the impacts of different irrigation schedules on the water balance components. Two different irrigation treatments were evaluated, one based on a scientific approach (“optimal” treatment) with different irrigation frequencies (daily and bi-weekly applications) and the second one based on the empirical practices of the farmers of the area (“farmer” treatment). The field data allowed the evaluation and calibration of a deterministic mechanistic model (HYDRUS) which was subsequently used as a prediction tool to study various irrigation management scenarios. The experimental results demonstrate a poor efficiency of the farmers’ practices and that inadequate water supply leads to lower yields than in the case of “optimal” irrigation. The irrigation frequency was found to be important with irrigating twice a week instead of once a day leading to an increase of the root-zone water storage, a better crop water availability through the whole root zone and higher yields. It appears that, in the specific climatic context of the study area, frequent applications of small irrigation depths cause the irrigation water to remain near the soil surface where it is subsequently evaporated. The simulated results confirm that changes of the irrigation frequency have a strong influence on the components of the water balance. A decrease of the irrigation frequency causes an increase of the water stored in the root zone, an augmentation of the crop transpiration and a decrease of the water content in the immediate vicinity of the soil surface, leading to reduced evaporation. At the same time, drainage increases somewhat, but remains nevertheless low enough not to threat seriously the quality of the groundwater.

Purpose To compare retinal nerve fiber layer (RNFL) thickness measured by Heidelberg retina tomograph (HRT) and nerve fiber analyzer (GDx). Methods Twenty eyes of 20 consecutive healthy subjects were recruited for this study. Each subject had a normal visual field and a normal optic nerve head, which was assessed by slit-lamp biomicroscopy using a 90° lens. Using the HRT and GDx, RNFL measurement was calculated as for software vs 2.01 and vs 1.0.14, respectively. Retinal nerve fiber layer thickness was evaluated for the entire annulus surface every 5° degrees. RNFL was assessed by HRT and GDx. HRT RNFL measurement was calculated at 0 üm from the edge, while GDx RNFL measurement at 1.75 disc diameter as for software. The difference between the highest points and the deepest points was calculated and compared. Furthermore, because of the possibility of different scales in the two systems, the following ratio was calculated: superior/inferior, superior/temporal, superior/nasal, inferior/temporal, and inferior/nasal. Results When the entire RNFL thickness was considered, a significant (p<0.001) difference was found between the HRT and GDx measurements. A difference of 200 üm was found between the highest and the deepest HRT points while a difference of 40 üm was found between the highest and the deepest GDx points. Conclusions HRT and GDx RNFL measurements were statistically different in each sector. However, ratio parameters showed no difference between the obtained values except for superior/temporal ratio and inferior/temporal ratio.

Purpose: To investigate, in vitro, the influence of non-penetrating glaucoma surgery ( NPGS) and the influence of tightly suturing the superficial scleral flap on the aqueous outflow facility of isolated porcine eyes.Materials and methods: The anterior chambers of 12 enucleated porcine cadaver eyes were cannulated and perfused. NPGS was performed by the same surgeon. The overall ocular aqueous outflow facilities were assessed before and after the surgical interventions of NPGS, as well as after scleral flap closure.Results: The mean (SD) aqueous outflow facility, which was 0.164 (0.014) mul/min/mm Hg before surgery, increased significantly after NPGS to 1.584 (0.217) mul/min/mm Hg, p < 0.001. When the superficial flap was closed, the aqueous outflow facility significantly decreased (0.754 (0.107) &mu;l/min/mm Hg, p, 0.001) but remained significantly higher than preoperatively (p < 0.01). After suturing the superficial flap, the overall resistance increased to 1.625 (0.210) mul/min/mm Hg. The difference in the resistance to outflow before and after flap closure was 0.848 (0.169) mul/min/mm Hg.Conclusion: After NPGS suturing the scleral flap can modulate aqueous outflow resistance. The experimental set up described might provide an efficient model for the technical training of glaucoma surgeries.

AIM:To identify the value of using collagen implant in deep sclerectomy.METHODS:A prospective randomised trial of 104 eyes (104 patients) with medically uncontrolled primary and secondary open angle glaucoma. All patients had deep sclerectomy (DS), half of them with and the other half without a collagen implant (CI) sutured in the scleral bed. The main outcome measures were intraocular pressure (IOP), visual acuity, number of treatments preoperative and postoperative, and Nd:YAG goniopunctures.RESULTS:Mean follow up period was 44.5 (SD 21) months for the DS group and 43.9 (SD 14) months for the deep sclerectomy with a collagen implant (DSCI) group. The mean preoperative IOP was 23.3 (SD 7.2) mm Hg for the DS group and 25.6 (SD 4.9) mm Hg for the DSCI group. The mean IOP at the first postoperative day was 6.1 (SD 4.21) mm Hg for the DS group and 5.1 (SD 3.3) mm Hg for the DSCI group. At 48 months IOP was reduced by 40% (14 versus 23.3 mm Hg) for the DS group and by 50% (12.7 versus 25.6 mm Hg) for the DSCI group. Complete success rate, defined as IOP lower than 21 mm Hg without medication, was 34.6% (18/52 patients) at 48 months for the DS group, and 63.4% (33/52 patients) for the DSCI group. Qualified success rate; patients who achieved IOP below 21 mm Hg with or without medication, was 78.8% (41/52 patients) at 48 months and 94% (49/52 patients) for the DSCI group. The mean number of medications was reduced from 2.1 (SD 0.8) to 1.0 (SD 1) after DS, and was reduced from 2.2 (SD 0.7) to 0.4 (SD 0.6) in the DSCI group (p = 0.001)CONCLUSION:The use of a collagen implant in DS enhances the success rates and lowers the need for postoperative medication.

Aim: To study the possibility of using intraocular pressure (IOP) in the first postoperative day after sclerectomy as a prognostic indicator. Methods: Non-randomised prospective trial involving 105 eyes of 105 patients with medically uncontrolled primary and secondary open angle glaucoma. Visual acuity, IOP, and slit lamp examinations were performed before and after surgery at 1 and 7 days, and 1, 3, 6, 9, 12, 18, 24, 30, 36, 48, 54, 60, and 66 months. Visual field examinations were repeated every 6 months. A split point on day 1 IOP of less than or equal to 5 mm Hg (61%) versus more than 5 mm Hg (39%) was used. The first postoperative day IOP was examined in relation to the need for subsequent Nd:YAG goniopuncture, the subsequent use of postoperative antiglaucoma medications, and as a stratification variable in the Kaplan-Meier analyses. Results: The mean follow up was 43.2 (SD 14.3) months. The mean preoperative IOP was 26.8 (SD 7.7) mm Hg; the mean postoperative IOP was 5.1 (3.3) mm Hg at day 1 and 11.8 (3.1) mm Hg at month 60. Patients with IOP ⩽5 mm Hg had significantly fewer Nd:YAG goniopunctures (p = 0.0478). A significant (log rank test 0.0122) improvement for those with IOP ⩽5 mm Hg in terms of survival was detected using the most stringent criterion (IOP ⩽15 mm Hg with no medications). For patients with first postoperative day IOP ⩽5 mm Hg, the median time to failure was 24 months (95% CI: 12 to 30), but for those with an IOP >5 mm Hg, the median time to failure was only 6 months (CI 2 to 9). No significant difference in postoperative antiglaucoma medications was observed. Conclusion: First postoperative day IOP can be considered to be a significant prognostic indicator in deep sclerectomy.

PurposeTo compare the efficacy and safety of T-Flux implant versus Healon GV® in deep sclerectomy. MethodsRandomized prospective trial of 23 eyes of 20 patients with medically uncontrolled open angle glaucoma over a period of 24 months, who underwent deep sclerectomy with either Healon GV® or T-Flux implant. ResultsMean postoperative intraocular pressure was 13.2 ± 3.0 mm Hg with T-Flux implant (group 1) and 12.2 ± 3.5 mm Hg with Healon GV® (group 2), with a pressure reduction of 53.0% in group 1 (13.2 mm Hg vs. 28.1 mm Hg) and of 48.1% in group 2 (12.2 mm Hg vs. 23.5 mm Hg). Qualified and complete successes were 100% and 95.4% respectively. Pressures equal to or less than 15 mm Hg were 81.8% in group 1 and 90.9% in group 2 with or without treatment, and 63.6% in group 1 and 81.8% in group 2 without treatment. The number of glaucoma treatments dropped from 2.5 ± 0.9 to 0.4 ± 0.7 in group 1 and from 2.2 ± 1.0 to 0.2 ± 0.4 in group 2. The goniopuncture rate was 63.6% in group 1 and 36.4% in group 2, with a mean pressure drop of 6.1 ± 3.9 mm Hg and 3.25 ± 1.2 mm Hg respectively. Overall, slit-lamp diagnosed surgery-related complications included positive Seidel (13.6%), hyphaema (22.7%), choroidal detachment, and iris incarceration (4.5% each). At 2 years, ultrasound biomicroscopy showed mainly low reflective (40.1%) and flattened (36.4%) blebs. Principally latter ones were associated with the need for adjunctive treatment. A hypoechoic area in the suprachoroidal space was seen in at least 59.1% of eyes at 2 years and was not associated with lower intraocular pressure. ConclusionDeep sclerectomy is an effective and safe surgery. However, longer follow up and larger study groups are required to assess the additional benefit of nonabsorbable implants.