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At least 865 records · Page 48Linked to original sources

Endoresection of choroidal melanoma.

AIMS: The results of 52 endoresections for choroidal melanoma are reported. METHODS: The current technique involves vitrectomy, retinal incision over or peripheral to the tumour, haemostasis by raising intraocular pressure and by moderate hypotensive anaesthesia, choroidal incision around tumour, endoresection with vitrector, endodiathermy to bleeding points and residual tumour, fluid-air exchange to reattach retina, endolaser to achieve retinal adhesion around the coloboma and destroy residual tumour in the sclera, silicone oil injection with removal after 12 weeks, cryotherapy to the sclerotomies, and adjunctive ruthenium plaque radiotherapy in selected cases. RESULTS: Patients receiving primary endoresection had a mean age of 53 years, a mean largest basal tumour diameter of 8.2 mm, and a mean tumour thickness of 3.9 mm. 40 tumours extended to within 2 disc diameters of the optic disc, with 17 involving disc. Follow up ranged from 40 days to 7 years (median 20 months). At the last visit, 90% of eyes were retained, with vision of 6/6-6/12 (two), 6/18-6/36 (three), 6/60 to counting fingers (18), hand movements (nine), and light perception (four). The main complications were retinal detachment in 16 and cataract in 25. Secondary endoresection (11) was performed after plaque radiotherapy (four), photocoagulation (four), trans-scleral local resection (two), and proton beam radiotherapy (one), with retention of the eye in nine cases. By the close of the study, no patients developed definite local tumour recurrence but one died of metastatic disease 41 months postoperatively. CONCLUSION: Depending on tumour location, endoresection may conserve central vision or temporal field when radiotherapy would be expected to cause optic neuropathy. Longer follow up is necessary to establish the efficacy of tumour control.

Adult↗

The effect of acetazolamide on the movement of sodium into the posterior chamber of the dog eye.

The rate of appearance (entry) of 22Na into the posterior chamber of the eye was determined in eight dogs under control conditions and again after pretreatment with acetazolamide, 50 mg/kg i.v. In comparison with the paired controls, pretreatment with acetazolamide decreased the average rate of entry of 22Na by 29% during the first 3 minutes after the intravenous administration of a tracer dose of the isotope. In separate experiments, the volumes of the chambers of the dog eye and the rate of aqueous humor formation were determined for the purpose of calculating nascent fluid ion concentrations. Comparisons of sodium data with the previously reported anion data are made. Results support the suggestion that reduction of intraocular pressure caused by acetazolamide is partially, if not wholly, the result of the action of the drug to reduce the secretion of aqueous humor.

Acetazolamide↗

Treatment of reopened macular hole after vitrectomy by laser and outpatient fluid-gas exchange.

OBJECTIVE: This study aimed to assess a new nonsurgical treatment for patients who have previously undergone vitrectomy for macular hole with either persistent or reopened holes. DESIGN: A prospective, noncomparative, consecutive case series. PARTICIPANTS: Fifteen patients (15 eyes) were studied. INTERVENTION: Patients were treated by an outpatient method consisting of laser photocoagulation to the foveal pigment epithelium followed by fluid-gas exchange with 20% perfluoropropane gas and prone positioning. Patients without known allergy were treated with two doses of oral Diamox (250 mg) and ciprofloxacin (500 mg). MAIN OUTCOME MEASURES: Visual acuity, intraocular pressure, anatomic status of the macular hole, and cataract were the principal outcome measures studied. RESULTS: Thirteen of 15 macular holes were closed successfully with 1 or more procedures. All patients with macular hole closure achieved two lines or greater of vision improvement on Snellen testing. Three patients (20%) achieved 20/40 and nine (60%) achieved 20/80 or better. Three patients required more than one procedure. Four patients developed mild transient ocular hypertension. CONCLUSIONS: The combination of office-based outpatient fluid-gas exchange and laser appears to be a safe and cost-effective alternative to repeat surgery in selected patients with persistent or reopened macular holes after vitrectomy, in whom there are no visible epiretinal membranes, or in whom return to the operating room is undesirable for medical or personal reasons.

Aged↗

Effect of chitosan and of N-carboxymethylchitosan on intraocular penetration of topically applied ofloxacin.

The effects of chitosan hydrochloride (Ch-HCl) and of N-carboxymethylchitosan (CMCh), formulated in ophthalmic solutions, on the ocular pharmacokinetics of ofloxacin were studied in rabbits. The carboxymethylation of a chitosan of high molecular mass (1460 kDa) and deacetylation degree (89.9%) introduced 0.84 N-carboxymethyl groups per repeating unit. Aqueous solutions containing 1% (w/v) of either polymer showed a pseudoplastic rheologic behaviour, and, when instilled in rabbit eyes, produced no irritation. The kinetics of drug disappearance from tear fluid and the profiles of drug concentration in the aqueous humour versus time were determined and interpreted in the light of a pharmacokinetic model and of drug-polymer binding. Ch-HCl significantly enhanced intraocular drug penetration with respect to an isoviscous drug solution containing poly(vinyl alcohol) and to commercial ofloxacin eyedrops. This effect, which resulted in about 190% increase of the peak concentration in the aqueous, was ascribed to an increased corneal permeability. The polyanionic CMCh failed to enhance intraocular drug penetration. It nevertheless increased precorneal drug retention in virtue of its viscosity and of ofloxacin binding. Consequently, the residence time at concentrations higher than the MIC90 and the bioavailability of the antibiotic in the aqueous were increased by about 150 and 240%, respectively, with respect to the reference vehicle.

Animals↗

Refractive changes in silicone oil-filled pseudophakic eyes.

PURPOSE: We examined the refractive changes in pseudophakic eyes of patients with idiopathic macular hole treated with silicone oil injection. METHODS: Twenty consecutive eyes of 19 patients with idiopathic macular hole who had undergone successful pars plana vitrectomy using silicone oil tamponade were studied retrospectively. Lensectomy with intraocular lens (IOL) implantation was performed on each patient before vitreous surgery. Five biconvex type IOL models were used. After pars plana vitrectomy and fluid-air exchange, silicone oil was injected to replace the air completely. Macular hole closure was confirmed by optical coherence tomography, and silicone oil removal was performed. Manifest refractions before silicone oil filling, with silicone oil filling, and after silicone oil removal were determined. RESULTS: A mean hyperopic shift +/- SD in spherical equivalents of +5.69 +/- 1.71 diopters (P < 0.0001) was observed with silicone oil instillation. In contrast, a mean myopic shift +/- SD of -5.63 +/- 1.33 diopters was observed after silicone oil removal (P < 0.0001). The absolute value of the refractive shift showed a strong correlation with the posterior radius of the IOL (r = 0.699, P < 0.0001). CONCLUSION: IOL models with steeper posterior convex curvature result in larger refractive deviations in patients scheduled for silicone oil instillation.

Aged↗

Filtering blebs imaging by optical coherence tomography.

PURPOSE: To assess the ability of standard optical coherence tomography to visualize filtering blebs after glaucoma surgery. METHODS: A prospective interventional case series was conducted in a private practice. Twenty-nine eyes of 24 patients (21 with good, 2 with fair and 6 with poor intraocular pressure [IOP] control) were investigated. After the focus was manually adjusted on the conjunctiva, blebs were scanned perpendicularly to the limbus. RESULTS: Hyporeflective fluid-filled spaces were detected in 19 out of the 21 eyes with good IOP. Within this group, blebs were classified into three different categories according to their optical coherence tomography pattern: type A (featuring a thick wall and a single large fluid-filled space), type B (featuring a thin wall and multiple large fluid-filled spaces) and type C (featuring multiple, irregular and flattened fluid-filled spaces). Fluid-filled spaces were not observed in three out of the six eyes with poor IOP control. Trabeculectomy without antimetabolites was associated with type A blebs (P = 0.015, Fisher's exact test), mitomycin-C trabeculectomy with type B blebs (P = 0.0025) and mitomycin-C phacotrabeculectomy with type C blebs (P = 0.0173). CONCLUSIONS: Although it was not developed to evaluate the anterior segment of the eye, standard optical coherence tomography can visualize filtering blebs and reveal interesting details of their morphology. Clinicians using optical coherence tomography to diagnose glaucoma can take advantage of this ability of the instrument to obtain more information about their patients in the postoperative course of trabeculectomy and phacotrabeculectomy.

Adolescent↗

Ocular penetration of cyclosporin A. III: The human eye.

The distribution of cyclosporin A (CsA) in the blood, saliva, tears, aqueous humour, vitreous, and cerebrospinal fluid has been studied after oral treatment with 5 mg/kg/day of CsA or application of 2% CsA eye drops in olive oil solution. After oral treatment all patients had high CsA levels in blood. Measurable levels of CsA were also found in the saliva and tears. Patients without any intraocular inflammation or patients with mild uveitis did not have any detectable CsA in the aqueous humour. However, patients with severe uveitis had significant levels of CsA in the aqueous humour and in the vitreous. No CsA was found in the cerebrospinal fluid of two patients with central nervous system manifestations of Behçet's disease. After local treatment with 2% CsA eye drops no detectable levels of CsA were found in the blood, the saliva, the aqueous humour, or the vitreous even in patients with severe uveitis.

Aqueous Humor↗

Endogenous Serratia marcescens endophthalmitis with dark hypopyon: case report and review.

A case of endogenous Serratia marcescens endophthalmitis in a patient with diabetes, end-stage renal disease, and an indwelling venous catheter is reported. The patient presented with a tan hypopyon and elevated intraocular pressure. Diagnosis was established by positive blood, vitreous, conjunctival, and catheter tip cultures. After a deteriorating course the eye was enucleated. Gross and histopathologic examination revealed the presence of a dark hypopyon with iris necrosis and pigment dispersion and possible spontaneous globe perforation. This is the eleventh reported case of endogenous Serratia endophthalmitis. Previous association of a pink hypopyon and of pigmented vitreous fluid and Serratia endophthalmitis has been reported. This is the first case of dark hypopyon in endogenous Serratia marcescens endophthalmitis reported in the medical literature. Previous entities associated with dark hypopyon have been limited to intraocular melanoma and Listeria monocytogenes endophthalmitis. Dark hypopyon in the appropriate clinical setting may be useful in aiding diagnostic and therapeutic decisions.

Anterior Chamber↗

Modifying subsceral fluid pressure in an experimental model of mitomycin-C diffusion.

BACKGROUND: Episcleral application of mitomycin-C (MMC) during glaucoma filtration surgery hinders the post-operative wound healing. Diffusion through the sclera might result in a toxic effect on the ciliary body resulting in reduced aqueous humor production leading to post-operative hypotony. We developed an experimental model to investigate the influence of intraocular pressure on the diffusion of MMC through the sclera and in subscleral compartments. METHODS: Scleral quadrants of 10 human donor eyes were mounted on PMMA tubes filled with saline imitating the intraocular volume. By height variation of a coupled infusion line different intraocular pressures were simulated (0, 8, 23 and 80 mmHg). Additionally the model included a subscleral sponge to mimic the compartment of the ciliary body. The episcleral sides of the scleral quadrants were exposed for 1 min to sponges soaked with 200 microg ml(-1) MMC. An 8-mm-diameter scleral disk was punched out with a trephine and horizontally dissected with a kryotome. The MMC concentrations of scleral layers, epi-and subscleral sponges and the fluid within the tubes were analysed by means of high-performance liquid chromatography. RESULTS: The MMC concentration gradually declined from the episcleral sponge (165 microg ml(-1)) to the superficial (3.3 microg ml(-1)) and deep scleral layers (1.2 microg ml(-1)), and to the subscleral sponge (0.2 microg ml(-1)). We were able to detect very small concentrations of MMC in the fluid within the PMMA tubes (0.01 microg ml(-1)). CONCLUSION: We developed a new experimental in vitro model for investigating transscleral MMC diffusion. The different simulated intraocular pressures had no effect on the concentration gradient through the investigated compartments of our model.

Diffusion↗

Effect of humidity on posterior lens opacification during fluid-air exchange.

OBJECTIVE: To study the relationship of humidity and the rate of lens opacity formation during fluid-air exchange using an animal model. METHODS: Vitrectomy and fluid-air exchange was carried out using 16 eyes of 8 pigmented rabbits. One eye of each rabbit was exposed to dry air and the fellow eye received humidified air using an intraocular air humidifier. In each case, the percent humidity of the intraocular air was measured using an in-line hygrometer. Elapsed time from initial air entry to lens feathering was recorded for each eye, with the surgeon-observer unaware of the percent humidity of the air infusion. RESULTS: In each rabbit, use of humidified air resulted in a delay in lens feathering (P<.02), with an overall increase in time to feathering of 80% for humidified air vs room air. CONCLUSIONS: Use of a humidifier during fluid-air exchange prolongs intraoperative lens clarity in the rabbit model, suggesting that humidified air should prolong lens clarity during phakic fluid-air exchange in patients. CLINICAL RELEVANCE: Use of humidified air during vitrectomy and fluid-air exchange may retard the intraoperative loss of lens clarity, promoting better visualization of the posterior segment and enhancing surgical performance.

Air↗

Variations in intraocular pressure during closed-system surgical procedures.

True intraocular pressure (IOP) during closed-chamber anterior segment surgery and vitrectomy was measured in rabbits by inserting a miniature pressure sensor directly into the anterior chamber or into the vitreous. Infusion fluid pressure was also measured simultaneously with a sensor in the infusion line. Significant and rapid changes in IOP up to 110 mm Hg were observed during routine anterior segment and vitreous procedures. None of these IOP changes affected infusion line pressure, which was governed solely by the infusion bottle height. Furthermore, raising the infusion bottle produced minimal IOP elevation whenever fluid was flowing into and out of the eye via a surgical instrument or a wound. These results show the limitations of monitoring of infusion line pressure as a means for assessing IOP and stress the need for IOP control during surgery.

Animals↗

Pharmacological regulation of protein expression from adeno-associated viral vectors in the eye.

The control, over time and space, of the levels of therapeutic proteins is crucial for successful retinal gene therapy. We tested the ability of adeno-associated viral vectors (AAV) delivered intraocularly to release a secreted protein (erythropoietin (Epo) used as a marker) in the eye, either constitutively or in a pharmacologically regulated manner using the dimerizer-inducible transcriptional regulatory system. Following delivery of a constitutively expressing vector to the intravitreal or subretinal space of nude rats, Epo protein was detected in both the anterior chamber and vitreous fluids. A dual-vector system inducible by the dimerizer rapamycin and expressing Epo was administered into the subretinal space in an attempt to achieve pharmacologic control of trangene expression in the eye. Before induction with rapamycin, the intraocular Epo level was negligible. However, following a systemic administration of rapamycin, Epo was detected in the anterior chamber, peaking on day 3 and returning to baseline 2-3 weeks after withdrawal of the drug. Peak-induced Epo in the anterior chamber was proportional to the dose of rapamycin and was not detected in serum. Similar results were obtained following subretinal administration of the vectors in one nonhuman primate. The rapamycin inducible system promises to be useful for developing gene therapies for inherited retinal degeneration and ocular neovascularization.

Animals↗

Penetration of topically applied ciprofloxacin, norfloxacin and ofloxacin into the aqueous humor of the uninflamed human eye.

This study was undertaken to compare aqueous humor penetration of topical 0.3% ciprofloxacin, 0.3% norfloxacin and 0.3% ofloxacin in 63 patients undergoing cataract surgery. The patients were divided into two groups. Group 1 (long-term treatment) involved 30 patients undergoing cataract extraction who received either 0.3% ciprofloxacin, 0.3% norfloxacin or 0.3% ofloxacin topical drops. Each patient was preoperatively given a single drop per hour six times. At the time of surgery, 0.1 ml aqueous fluid was aspirated from the anterior chamber and immediately stored at -70 degrees C. Topically applied ciprofloxacin, ofloxacin and norfloxacin achieved mean aqueous humor levels of 2.80 +/- 1.07, 2.95 +/- 1.19 and 1.50 +/- 0.48 micrograms/ml respectively. There was no statistically significant difference in intraocular mean aqueous levels of ciprofloxacin versus ofloxacin. Topical ciprofloxacin and ofloxacin achieved mean aqueous humor levels significantly higher than norfloxacin (p < 0.001 and p < 0.0008 respectively). Group 2 (short-term treatment) involved 33 patients undergoing cataract extraction who received 0.3% ciprofloxacin, 0.3% ofloxacin and 0.3% norfloxacin topical drops. These patients were given one drop at 90 minutes and one drop 30 minutes preoperatively. At the time of surgery, 0.1 ml aqueous fluid was aspirated from the anterior chamber and immediately stored at -70 degrees C. Topically applied ciprofloxacin, ofloxacin and norfloxacin achieved mean aqueous humor levels of 1.11 +/- 0.50, 1.50 +/- 0.62 and 1.20 +/- 0.43 micrograms/ml respectively. There was no statistically significant difference in intraocular mean aqueous humor levels of ofloxacin versus norfloxacin and ciprofloxacin versus norfloxacin. Topical ofloxacin achieved a significantly higher mean aqueous humor level than ciprofloxacin (p < 0.03). All levels were above the minimum inhibitory concentrations of ciprofloxacin, ofloxacin and norfloxacin for most of the sensitive organisms.

Administration, Topical↗

Combined macular hole and cataract surgery.

PURPOSE: Cataract often develops after macular hole surgery, necessitating cataract surgery. We report a combination of macular hole surgery and cataract surgery on four eyes of four patients. METHODS: Four eyes of four patients had a full-thickness stage III or IV macular hole and some degree of cataract. Combined cataract surgery with intraocular lens implant and macular hole surgery was associated with intravitreal perfluoropropane at 15% concentration and with face-down positioning for 21 days. RESULTS: After combined cataract and macular hole surgery, the rim of subretinal fluid resolved successfully in four eyes of four patients. Twelve months after surgery, the macular hole reopened in one eye in association with the new onset of macular pucker. Best-corrected visual acuities ranged from 20/25 to 20/100 12 months after surgery, while preoperative visual acuities with best correction were 20/70 to 20/200. CONCLUSIONS: In selected cases, a combination of cataract surgery with intraocular lens implant and macular hole surgery offers advantages. This combined approach warrants consideration.

Aged↗

Pseudophakic corneal edema: A review of mechanisms and treatments.

PURPOSE: To review the pathological mechanisms and treatments for pseudophakic corneal edema (PCE), one of the most common indications for penetrating keratoplasty. METHODS: The literature was examined for the molecular biology associated with PCE and for the surgical and medical treatments for this disorder. RESULTS: The incidence of PCE has recently been decreasing because of improved surgical instrumentation, including improvements in intraocular lens designs that cause less trauma to the corneal endothelium. Extracellular matrix and growth factor abnormalities occur in PCE corneas and recently, the role of aquaporins, which are involved in the regulation of fluid movement across cells, has been investigated. CONCLUSIONS: Although newer treatment options have been suggested, penetrating keratoplasty still remains the most definitive treatment and has the highest success rate.

Cataract Extraction↗