Outcomes of levator advancement and Müller muscle-conjunctiva resection for the repair of upper eyelid ptosis.

Both the Müller muscle-conjunctiva resection (MMCR) and levator advancement (LA) procedures can be used to manage ptosis in patients with good levator function. The aim of this article is to evaluate the efficacy and cosmetic outcomes of the two procedures. The clinical records of 29 consecutive eyelids of 26 patients undergoing MMCR and 30 eyelids of 23 patients undergoing LA were analysed. Eleven (42%) in the LA group and 9 (39%) in the MMCR group were male. The preoperative eyelid measurements were significantly different in the LA compared to the MMCR groups, in terms of palpebral aperture (PA) (6.3 vs 7.4, p = 0.01), marginal reflex distance 1 (MRD1) (-0.1 vs 1.5, p < 0.001) and levator function (LF) (12.1 vs 13.4, p = 0.03). The MRD1 1 month post-surgery was slightly less in the LA group compared to the MMCR group (2.6 vs 3.18 mm, p = 0.047) but not significantly different at months 3 and 6. The final change in MRD1 was significantly higher in the LA group (2.93 vs 1.76, p = 0.004). The MMCR group had a lower incidence of lid contour abnormalities (0% vs 20%, p = 0.01) and overcorrection (0% vs 13%, p = 0.04). There was no statistically significant difference in the rates of undercorrection in either group. Both the MMCR as well as LA procedures are effective for mild to moderate ptosis in patients with good levator function. Patients undergoing MMCR had higher success rates, better preservation of the natural lid contour, and a lower incidence of overcorrection than patients undergoing LA.

Necrotising fasciitis of the eyelid with toxic shock due to Pseudomonas aeruginosa.

Necrotising fasciitis is a rare and rapidly spreading soft tissue infection characterised by widespread necrosis of the superficial fascia and usually occurring in the limbs and the abdominal wall. Periocular necrotising fasciitis is unusual due to the excellent blood supply of the facial region. The usual pathogens are Group A beta-haemolytic Streptococcus and Staphylococcus aureus. We report a case of Pseudomonas necrotising fasciitis of the eyelid with septic shock, initially diagnosed as hordeolum in a young immunocompromised Chinese woman. Early recognition of the condition, followed by timely intervention with surgical debridement and intensive intravenous antibiotic treatment led to a favourable prognosis. It is important for general physicians to recognise the cardinal signs of necrotising fasciitis, as early treatment with timely surgical debridement and supportive medical therapy is the mainstay to successful management.

Partitioning of etofenprox under simulated California rice-growing conditions.

BACKGROUND: The pyrethroid insecticide etofenprox is of current interest to rice farmers in the Sacramento Valley owing to its effectiveness against the rice water weevil, Lissorhoptrus oryzophilus Kuschel. This study aimed to describe the partitioning of etofenprox under simulated rice field conditions by determining its Henry's law constant (H) (an estimate of volatilization) and organic carbon-normalized soil-water distribution coefficient (K(oc)) at representative field temperatures. A comparison of etofenprox and lambda-cyhalothrin is presented using a level-1 fugacity model. RESULTS: Experimental determination of H revealed that etofenprox partitioned onto the apparatus walls and did not significantly volatilize; the maximum value of H was estimated to be 6.81 x 10(-1) Pa m(3) mol(-1) at 25 degrees C, based on its air and water method detection limits. Calculated values for H ranged from 5.6 x 10(-3) Pa m(3) mol(-1) at 5 degrees C to 2.9 x 10(-1) Pa m(3) mol(-1) at 40 degrees C, based on estimated solubility and vapor pressure values at various temperatures. Log K(oc) values (at 25 degrees C) were experimentally determined to be 6.0 and 6.4 for Princeton and Richvale rice field soils, respectively, and were very similar to the values for other pyrethroids. Finally, temperature appears to have little influence on etofenprox sorption, as the log K(oc) for the Princeton soil at 35 degrees C was 6.1. CONCLUSION: High sorption coefficients and relatively insignificant desorption and volatilization of etofenprox suggest that its insolubility drives it to partition from water by sorbing to soils with high affinity. Offsite movement is unlikely unless transported in a bound state on suspended sediments.

The behavior of clomazone in the soil environment.

BACKGROUND: Clomazone is a herbicide used to control broadleaf weeds and grasses. Clomazone use in agriculturally important crops and forests for weed control has increased and is a potential water contaminant given its high water solubility (1100 microg mL(-1)). Soil sorption is an environmental fate parameter that may limit its movement to water systems. The authors used model rice and forest soils of California to test clomazone sorption affinity, capacity, desorption, interaction with soil organic matter and behavior with black carbon. RESULTS: Sorption of clomazone to the major organic matter fraction of soil, humic acid (HA) (K(d) = 29-87 L kg(-1)), was greater than to whole soils (K(d) = 2.3-11 L kg(-1)). Increased isotherm non-linearity was observed for the whole soils (N = 0.831-0.893) when compared with the humic acids (N = 0.954-0.999). Desorption isotherm results showed hysteresis, which was greatest at the lowest solution concentration of 0.067 microg mL(-1) for all whole soils and HA extracts. Aliphatic carbon content appeared to contribute to increased isotherm linearity. CONCLUSION: The results indicate that clomazone does not sorb appreciably to sandy or clay soils. Its sorption affinity and capacity is greater in humic acid, and consequently clomazone has difficulty desorbing from soil organic matter. Sorption appears to follow processes explained by the dual-mode model, the presence of fire residues (black carbon) and a recently proposed sorption mechanism.

Environmental fate and toxicology of carbaryl.

Carbaryl is an agricultural and garden insecticide that controls a broad spectrum of insects. Although moderately water soluble, it neither vaporizes nor volatilizes readily. However, upon spray application the insecticide is susceptible to drift. It is unstable under alkaline conditions, thus easily hydrolyzed. Carbaryl has been detected in water at ppb concentrations but degradation is relatively rapid, with 1-naphthol identified as the major degradation product. Indirect and direct photolysis of carbaryl produces different naphthoquinones as well as some hydroxyl substituted naphthoquinones. Sorption of the insecticide to soil is kinetically rapid. However, although both the mineral and organic fractions contribute, because of its moderate water solubility it is only minimally sorbed. Also, sorption to soil minerals strongly depends on the presence of specific exchangeable cations and increases with organic matter aromaticity and age. Soil microbes (bacteria and fungi) are capable of degrading carbaryl; the process is more rapid in anoxic than aerobic systems and with increased temperature and moisture. Carbaryl presents a significant problem to pregnant dogs and their offspring, but some have questioned the applicability of these data to humans. In addition, for toxicokinetic and/or physiological reasons, it has been argued that dogs are more sensitive than humans to carbaryl-induced reproductive or developmental toxicity. However, these arguments are based on either older pharmacokinetic studies or on speculation about possible reproductive differences between dogs on the one hand and rats and humans on the other. In view of the wider evidence from both human epidemiological and laboratory animal studies, the question of the possible developmental and reproductive toxicity of carbaryl should be considered open and requiring further study.

Review of orbital imaging.

CT and MRI are commonly used in the evaluation of patients with suspected orbital disease. Many different diseases may present within this small anatomical space. The purpose of this article is to present a diagnostic strategy based on a compartment model. Localizing pathology to sinus, bone, extraconal space, muscle cone, intraconal space, optic nerve, globe or lacrimal fossa allows significant reduction in the number of differential diagnoses as these compartments contain different tissues which disease may involve or arise from. Certain diseases may also present in multiple compartments. Common diseases which might present in one or multiple compartments will be discussed.

Chemistry and fate of simazine.

Simazine, first introduced in 1956, is a popular agricultural herbicide used to inhibit photosynthesis in broadleaf weeds and grasses. It is a member of the triazine family, and according to its physicochemical properties, it is slightly soluble in water, relatively nonvolatile, capable of partitioning into organic phases, and susceptible to photolysis. Sorption and desorption studies on its behavior in soils indicate that simazine does not appreciably sorb to minerals and has the potential to leach in clay and sandy soils. The presence of organic matter in soils contributes to simazine retention but delays its degradation. The primary sorptive mechanism of simazine to OM has been proposed to be via partitioning and/or by the interaction with functional groups of the sorbent. Farming practices directly influence the movement of simazine in soils as well. Tilled fields lower the runoff of simazine when compared to untilled fields, but tilling can also contribute to its movement into groundwater. Planting cover crops on untilled land can significantly reduce simazine runoff. Such practices are important because simazine and its byproducts have been detected in groundwater in The Netherlands, Denmark, and parts of the U.S. (California, North Carolina, Illinois, and Wisconsin) at significant concentrations. Concentrations have also been detected in surface waters around the U.S. and United Kingdom. Although the physicochemical properties of simazine do not support volatilization, residues have been found in the atmosphere and correlate with its application. Although at low concentrations, simazine has also been detected in precipitation in Pennsylvania (U.S.), Greece, and Paris (France). Abiotically, simazine can be oxidized to several degradation products. Although hydrolysis does not contribute to the dissipation of simazine, photolysis does. Microbial degradation is the primary means of simazine dissipation, but the process is relatively slow and kinetically controlled. Some bacteria and fungal species capable of utilizing simazine as a sole carbon and nitrogen source at a fast rate under laboratory conditions have been identified. Metabolism of simazine in higher organisms is via cytochrome P-450-mediated oxidation and glutathione conjugation.

Influence of phosphate and copper on reductive dechlorination of thiobencarb in California rice field soils.

The potential for reductive dechlorination of the herbicide thiobencarb (TB) by microbes and its prevention in saturated anaerobic rice field soils was examined in laboratory microcosms. TB is effective in controlling both annual grasses and broadleaf weeds. In anoxic microcosms, TB was effectively degraded within 30 days to its dechlorinated product, deschlorothiobencarb (DTB), in two Sacramento Valley rice field soils. TB dechlorination, and subsequent degradation, followed pseudo-zero- (lag phase) and first-order (degradation phase) kinetics. Logistic regression analysis (r2 > 0.841) produced a half-life (t(1/2)) in nonsterile soils ranging from 10 to 15 days, which was also observed when microcosms were amended with low concentrations (<3 mg L(-1)) of copper (Cu2+; as the fungicides Cu(OH)2 and CuSO4.5H2O). High Cu2+ concentrations (>40 mg L(-1)) were added to the microcosms to determine if copper toxicity to dechlorinating microbes is concentration dependent within the range used. After 30 days, the low-copper-amended soils closely resembled the nonsterile experiments to which no Cu2+ was added while the high-copper-amended microcosms were similar to the sterile experiment. Microcosms were also separately amended with 5.7 g L(-1) phosphate (PO4(2-); as KH2PO4), a nutrient regularly applied to rice fields. Phosphate-amended experiments also showed TB degradation, but no DTB formation, indicating the phosphate played a role, possibly as a microbial inhibitor or an alternative electron acceptor, in limiting the dechlorination of TB. In summary, TB dechlorination was inhibited at high Cu(OH)2, CuSO4.5H2O, and KH2PO4 concentrations.

An unusual presentation of a giant frontal sinus mucocele manifesting with a subcutaneous forehead mass.

INTRODUCTION: To describe the unusual manifestation of a giant frontal sinus mucocele. CLINICAL PICTURE: A 33-year-old female presented with blurring of vision in the left eye, periorbital swelling and a painless forehead mass. There was proptosis, partial ptosis, and an elongated, soft, subcutaneous mass over the left side of the forehead. CT scan showed a mass arising from the frontal sinus with both intraorbital and intracranial extension. TREATMENT: Surgical excision of the mass confirmed the diagnosis of a mucocele. OUTCOME: Postoperatively, the patient was asymptomatic. CONCLUSIONS: A subcutaneous soft-tissue mass may be the presenting complaint of a frontal mucocele. Careful examination of the surrounding skin may suggest the diagnosis of sinus-related disease and thus direct appropriate investigations.

Identification and characterization of sorption domains in soil organic matter using strucuturally modified humic acids.

The sorption of phenanthrene was examined in humic acids (HAs) from different sources: a compost, a peat soil, and a mineral soil. Sub-samples of each HA were subjected to bleaching or hydrolysis to remove predetermined chemical groups from their structures. Bleaching successfully removed a large percentage of rigid, aromatic moieties, whereas hydrolysis removed the mobile, carbohydrate components. Phenanthrene sorption by all HAs was nonlinear (N < 1). However, the phenanthrene isotherms of the bleached HAs were more linear than those of the untreated HAs, whereas the removal of the carbohydrate components by hydrolysis produced more nonlinear isotherms. The introduction of pyrene to the phenanthrene sorption system yielded more linear isotherms for all the HAs, indicative of competitive sorption. Proton spin-spin (1H T2) relaxation determined by nuclear magnetic resonance (NMR) was used to identify separate rigid (condensed) and flexible (expanded) 1H populations and to determine their distribution. These 1H domains were highly sensitive to temperature and correlated well with reported glass transition temperatures for HAs. In combination with the chemical treatments, sorption, and spectroscopic data, we were able to observe some significant relationships among chemical groups, sorption behavior, and structural characteristics.

Sorption and desorption of naphthalene by soil organic matter: importance of aromatic and aliphatic components.

Nonlinear isotherm behavior has been reported for the sorption of hydrophobic organic compounds (HOCs) in soil organic matter (SOM), but the exact mechanisms are unknown. Our objective was to provide insight into the sorption mechanism of HOCs in SOM by studying the sorption-desorption processes of naphthalene in a mineral soil, its humic fractions, and lignin. Additionally, humin and lignin were used for studying the effects of temperature and cosolvent on HOC sorption. All isotherms were nonlinear. The humin and lignin isotherms became more linear at elevated temperatures and with the addition of methanol indicating a condensed to expanded structural phase transition. Isotherm nonlinearity and hysteresis increased in the following order: soil humic acid (HA) < soil < soil humin. Of the samples, aliphatic-rich humin exhibited the largest degree of nonlinearity and had the highest sorption capacity for naphthalene. High nonlinearity and hysteresis in humin were most likely caused by its condensed structure. A novel aliphatic, amorphous condensed conformation is proposed. This conformation can account for both high sorption capacities and increased nonlinearity observed for aliphatic-rich samples and can explain many sorption disparities discussed in the literature. This study clearly illustrates the importance of both aliphatic and aromatic moieties for HOC sorption in SOM.

Antero-medial orbital masses associated with nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal carcinoma (NPC) involves the orbits through direct extension to the orbital apex via the cavernous sinus. Anterior orbital masses are very rare with only a few anecdotes in the literature about an anterior spread via nasal cavity or tumour arising de novo from the lacrimal sac. Reactive lymphoid hyperplasia in the orbit has never been reported in association with NPC. MATERIALS AND METHODS: Three cases that presented with antero-medial orbital mass in association with NPC are described. Two of the three cases including one with bilateral orbital mass, had biopsy proven NPC in the orbit and presented with tearing due to lacrimal sac involvement with a palpable mass in the anteromedial orbit. The third case presented with a left antero-medial orbital mass, which on biopsy proved to be a reactive lymphoid hyperplasia. He was detected to have NPC while investigating the orbital mass. All had raised serum levels of IgA against Epstein-Barr virus (EBV). DISCUSSION: The possible mode of spread in our case with bilateral involvement is most likely to be a metastasis, though a microscopic anterior spread through the nasal cavity and nasolacrimal duct could not be ruled out despite there being no evidence of tumour in the original site or nasal cavity. In the second case, the tumour spread from the nasal cavity into the orbit is clearly via the nasolacrimal duct. The third patient presents an interesting association of lymphoproliferative disorder and NPC with Epstein-Barr virus infection. CONCLUSION: Anterior orbital masses involving nasolacrimal duct and lacrimal sac are rare in NPC, but can occur. A rare association of a reactive lymphoid hyperplasia in the orbit with NPC is described.

Ophthalmic involvement in cranio-facial trauma.

OBJECTIVES: This is a retrospective descriptive case study which will look into the spectrum of ophthalmic involvement in cases with orbital and eye injuries after cranio-facial trauma and to analyse the visual and motility outcome. MATERIAL: One hundred and four cases with ophthalmic involvement after cranio-facial trauma that were referred to and seen in the eye department of a tertiary teaching hospital in Singapore between 1991-97 were included in the study. METHODS: The case records of 104 such patients were traced. The demographic data, the mode of injury, the type of fracture sustained and presence of serious eye injury were noted. The details about visual acuity, significant diplopia and enophthalmos at the first and last visits were charted. Presence of traumatic optic neuropathy including the type of treatment given was recorded. RESULTS: There was a male preponderance (82%). The industrial accidents were 21%, only next to road traffic accidents, which constituted approximately 36.5%. The predominant types of fractures seen were blow-out orbital fractures, complex fractures comprising of Le-Fort II, III, panfacial and fronto-basilar skull fractures. Diplopia was the most common presenting feature (40%) with visual acuity disturbance (23% having <6/60) as the next most common finding. Traumatic optic neuropathy was seen in 20% of patients and serious eye injury was present in 9% of patients. The incidence of traumatic optic neuropathy was significantly higher (p<0.001) in patients with complex fractures and fronto-basilar fractures, as compared to the blow-out and zygomatico-maxillary fractures. Analysis of final results indicated 15% as having significant diplopia in one or more gazes and 12.5% as having a vision of <6/60. CONCLUSION: Diplopia and visual acuity disturbances seem to be the most common ophthalmic presentations in cranio-facial trauma. A significant number of patients suffer from poor vision and significant diplopia despite treatment.

Ocular prosthetics: use of a tissue conditioner material to modify a stock ocular prosthesis.

The custom-made ocular prosthesis contributes to enhanced tissue health of the anophthalmic socket. For this purpose, an acrylic resin ocular prosthesis may be modified, by using an appropriate dental impression material and being adapted closely to the anophthalmic socket. The modeling impression material is subsequently replaced by acrylic resin. This article describes the application of a viscoelastic tissue conditioner material, as an impression medium for prosthetic modification of an ocular prosthesis. The tissue conditioner material exhibits favorable tissue compatibility, adhesion to acrylic resin, and detailed surface registration. These advantages facilitate the clinical procedure and evaluation of modifications made to the ocular prosthesis.

Visual recovery following treatment with very high dose corticosteroid in traumatic optic neuropathy.

Optic nerve compression is a true ophthalmic emergency. In addition to causes such as tumours, infection, mucoceles and granulomas, the majority of cases are the result of orbitofacial or closed-head trauma. The appropriate management of such cases is controversial; with some authors favouring surgical decompression while others advocate medical treatment using very high-dose corticosteroids, or a combination of both. We report a case of traumatic optic neuropathy in which there was marked improvement in visual acuity following the administration of methylprednisolone.

Oriental eyelids--anatomical and surgical considerations.

There are subtle anatomical differences between the oriental and occidental eyelids. Creation of upper eyelid crease, otherwise known as "Double Eyelid" has been the single most popular cosmetic surgical procedure among the affluent Asians to enhance the beauty of their eyelids. It is important for the surgeon to be familiar with the anatomical differences in order not to westernise their facial features but to blend his creation with the existing facial features. This is true of any surgical procedure in the lids, be it ptosis correction or blepharoplasty for excess skin and bags in the eyelids, in order to produce good cosmetic results.

Spontaneous hematic cysts of the orbit presenting with acute proptosis. A report of three cases.

Three cases of spontaneous hematic cyst of the orbit are described. All cases presented with acute onset of proptosis, conjunctival chemosis, choroidal folds, restricted ocular movement, and optic nerve compression syndrome with very poor vision. A computed tomography scan demonstrated a cystic lesion situated in the upper part of the orbit. Exploration revealed a cyst containing chocolate-colored fluid. Visual recovery was complete in two of three cases. There was no definite history of trauma in all three cases. Chronic hematic cysts have been described recently, but cases with acute onset such as ours have not to our knowledge been described clearly.