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Biomedical subjects

A Alhalel

Publications and source records attributed to A Alhalel.

15 recordsLinked to original sources
PubMed2001

Management of persistent loculated subretinal fluid after pneumatic retinopexy.

AIM: To report on the incidence and management of a unique and troublesome complication of pneumatic retinopexy-localised, delayed subretinal fluid absorption (DSRFA). METHODS: A retrospective chart review was done for all patients who underwent pneumatic retinopexy for retinal detachment over a 5 year period to identify the patients with DSRFA. RESULTS: Seven phakic patients (five females, two males, age range 26-87 years) were identified with the phenomenon of delayed resolution of subretinal fluid after pneumatic retinopexy and cryotherapy. In four patients the subretinal fluid involved the macula. Time taken to complete absorption of the subretinal fluid ranged from 10 to 26 months. In one patient there was still residual fluid inferiorly at 18 months of follow up. During the follow up period additional procedures were performed--scleral buckling (five eyes), pars plana vitrectomy (one eye), and mild laser scatter to extramacular areas of shallow subretinal fluid (four eyes). None of these procedures appeared to influence the rate of fluid absorption. CONCLUSIONS: Loculated subretinal fluid following pneumatic retinopexy may persist for very long periods, extending up to more than 2 years. Additional surgical procedures or laser photocoagulation do not affect the rate of subretinal fluid absorption. Spontaneous reattachment eventually occurs in most eyes, and conservative management is indicated.

Adult↗
PubMed2000

Reduced rate of retinal detachment following silicone oil removal.

PURPOSE: To investigate the rate of retinal redetachment and other complications after silicone oil removal over a 4-year period. METHODS: Retrospective analysis of charts of patients who underwent vitrectomy and silicone oil injection between January 1994 and June 1998 followed by oil removal. RESULTS: Sixty-eight eyes of 67 patients were included. The average follow-up time after oil removal was 15 months. Significant retinal redetachment developed in 6 eyes (8.8%). The redetachment rate was slightly higher in the 32 eyes with proliferative vitreoretinopathy (9.3%) than in the 36 eyes with other pathologies (8.3%). The average time to redetachment was 4.2 months. These eyes were reoperated and reattached, and at the end of the follow-up, three retained silicone oil. Two other eyes without redetachment were hypotonus after oil removal. Cataract extraction and intraocular lens implantation were performed at the time of oil removal in 18 eyes; 2 (11%) developed redetachment. Visual acuity improved significantly after oil removal (P < 0.001). CONCLUSION: The rate of retinal redetachment after removal of silicone oil in recent years is low compared with previous series. The authors attribute this reduction to the improved surgical management of complicated retinal detachments; particularly, the introduction of perfluorocarbon liquids and wide-field viewing systems and the widespread use of endolaser.

Adolescent↗
PubMed2000

ICGA-guided laser photocoagulation of feeder vessels of choroidal neovascular membranes in age-related macular degeneration. Indocyanine green angiography.

PURPOSE: To report the ability of indocyanine green angiography (ICGA) with a confocal scanning laser ophthalmoscope (SLO) to identify feeder vessels of choroidal neovascular membranes (CNVM) secondary to age-related macular degeneration (ARMD) and to show the feasibility of inducing complete closure of the CNVM by photocoagulation targeted exclusively to the feeder vessels. METHODS: Five consecutive patients with exudative ARMD in whom ICGA with the confocal SLO showed extrafoveal feeder vessels supplying choroidal neovascular nets had laser photocoagulation done only to the feeder vessels. In two patients, two separate membranes were seen. RESULTS: Laser photocoagulation resulted in closure of the feeder vessels and the CNVM in four patients. Complete closure was achieved with one treatment in one patient and with two treatments in three patients. In one patient, two treatments failed to close the feeder vessel and the CNVM, but a third, more intense laser treatment resulted in temporary closure of the feeder vessel and CNVM, which recanalized 2 to 4 weeks later with development of a large rip in the retinal pigment epithelium. In one patient, two separate CNVMs grew from the edge of the laser scars, but they were not directly related to the original CNVM and its feeder vessel, and were treated successfully. The same eye later developed subfoveal occult CNVM with gradual deterioration of visual acuity. In the other four patients, visual acuity improved in two and was unchanged in two. CONCLUSIONS: Indocyanine green angiography with the confocal SLO can identify choroidal feeder vessels supplying CNVM secondary to ARMD. Laser treatment to such extrafoveal feeder vessels, particularly in membranes that are large or subfoveal, may be effective in closing the feeder vessel and CNVM with preservation of the fovea and central vision. More than one treatment may be required, however, and failures and complications may be expected with this treatment modality.

Aged↗
PubMed1996

Role of blood components in ocular silicone oil emulsification. Studies on an in vitro model.

PURPOSE: To develop an in vitro model for silicone oil emulsification and to explore the blood components involved in this process. METHODS: The capacity of various blood components to support silicone oil (1000 CS) emulsification was studied by applying 0.5 ml oil on top of 0.5 ml saline containing various blood components. Each tube was sonicated for 150 seconds and centrifuged at 5000 g for 20 minutes. Three phases were noted in the tube: At the top was clear silicone oil, in the middle was emulsified silicone oil, and at the bottom was aqueous solution. The tubes were photographed, and the percentage of the phase length containing emulsified silicone oil (middle) of the total length of the three phases was calculated from the projected image of each tube. RESULTS: Emulsified silicone oil in plasma or serum was initiated after 100 seconds of sonication and quickly reached maximum (approximately 80%) at 120 seconds. The size of these oil droplets prepared in vitro was 0.0467 +/- 0.028 mm, closely resembling that observed in oil samples removed from a patient's anterior chamber (0.038 +/- 0.018 mm). Under these conditions, silicone oil emulsified in the presence of whole blood cells occurred only at a concentration of 120 micrograms protein/ml; in the presence of red blood cell membranes, it occurred at a concentration of 60 micrograms protein/ml. Lipoprotein-deficient serum failed to support emulsification; however, samples of high-density lipoprotein and low-density lipoprotein supported this process. Purified high-density lipoprotein-apolipoproteins supported oil emulsification. The addition of phosphatidylcholine further enhanced this process, but phosphatidylcholine alone failed to support emulsification. CONCLUSIONS: A simple and fast in vitro model to study factors affecting silicone oil emulsification was developed. Using this model, red blood cell membranes, plasma lipoproteins, and purified HDL-apolipoproteins supported silicone oil emulsification. Lipids did not, but they had the capacity to enhance the apolipoprotein-supported emulsification.

Blood Cells↗
PubMed1995

The impact of the macular photocoagulation study results on the treatment of exudative age-related macular degeneration.

OBJECTIVE: To determine the percent of cases with all primary forms of exudative age-related macular degeneration that are eligible for treatment by the Macular Photocoagulation Study (MPS) guidelines in a retina clinic serving both as a primary care center and as a referral center. DESIGN: Fluorescein angiograms of patients with age-related macular degeneration examined at the Goldschleger Eye Institute, Sheba Medical Center, Tel Hashomer, Israel, during a 5-year period (1985 to 1990) were randomly selected and reviewed. Angiograms showing all forms of exudative age-related macular degeneration were eligible. The first 100 eligible angiograms identified constituted the study series and were classified into four groups: active choroidal neovascularization (CNV), pigment epithelium detachment, hemorrhage, and disciform scars. The active CNVs were further divided into three subgroups: classic (well defined), occult (poorly defined), and combined. Eligibility for laser treatment was determined exclusively with use of the published MPS recommendations for treatment of extrafoveal, juxtafoveal, and subfoveal membranes. RESULTS: There were 10 cases in the pigment epithelium detachment group, 11 cases in the hemorrhagic group, and 16 cases with disciform scars. All of these 37 cases were ineligible for treatment by MPS guidelines. Sixty-three eyes had active membranes; 37 were classic CNVs (eight extrafoveal, seven juxtafoveal, and 22 subfoveal). All extrafoveal and juxtafoveal CNVs were found to be eligible for laser treatment. Eleven membranes of the subfoveal group were larger than 2 disc areas, a size for which the MPS did not demonstrate benefit from laser treatment. There were 19 membranes in the strictly occult CNV subgroup, all of them untreatable by MPS criteria. Seven cases had both occult and classic CNV, and all were larger than 3.5 disc areas and therefore ineligible for treatment. Overall, 26 cases were eligible for treatment by strict MPS criteria; these constitute 26% of the whole series and 41% of the active CNV cases in the series. CONCLUSIONS: Our results indicate that the MPS guidelines for laser treatment are applicable only to a minority of the cases with exudative age-related macular degeneration presenting to our clinic. Further studies should be conducted to identify additional treatment modalities for this common eye disease.

Choroid↗
PubMed1995

Ocular effects of hyoscine in double dose transdermal administration and its reversal by low dose pyridostigmine.

The potential of low dose (30 mg t.i.d) pyridostigmine to reduce the ocular side effects of double dose transdermal controlled release hyoscine was evaluated by the study of near visual acuity, accommodation amplitude and pupil diameter in a placebo controlled, double masked study. We studied 47 healthy men (age 18-21 yr) in 3 groups: 16 assigned to placebo hyoscine and placebo pyridostigmine, 15 assigned to double dose hyoscine and placebo pyridostigmine, and 16 to double dose hyoscine and pyridostigmine. Subjects were tested during 48 h of treatment and 48 h of washout period. Blood cholinesterase inhibition level and amount of hyoscine released from the patches were used as parameters of reliability. Difference between groups was assessed using change from baseline scores. Double dose hyoscine caused decrease in near visual acuity to a mean of 14/18. Accommodation amplitude was decreased in the double dose transdermal hyoscine group from 9.19 +/- 1.04 to 4.83 +/- 1.97 diopters of accommodation. This decrease was significant when compared to the placebo group (p < 0.05) and to the pyridostigmine-protected group (p < 0.05). Pyridostigmine, however, did not significantly change the hyoscine-induced mydriasis of 1.47 + 0.15 mm change from baseline (p < 0.05). These results suggest that pyridostigmine administration may be beneficial in shortening recovery time when near vision impairment is experienced following single and double dose transdermal hyoscine administration.

Adolescent↗
PubMed1993

Long-term follow up of accidental parafoveal laser burns.

The findings after 12 years of follow-up evaluation of 2 patients who sustained accidental parafoveal and juxtafoveal Nd:YAG laser injuries are reported. In both cases, the fovea was not destroyed by the initial insult and early scar formation. Both cases demonstrated, after more than a decade, minimal visual deficit without significant late complications. In spite of early decrease in visual performance, the long-term prognosis for Q-switched Nd:YAG laser retinal lesions in which the fovea was not directly involved in the injury or its repair mechanisms is relatively benign.

Adult↗
PubMed1992

Prevention of peripheral side-effects of transdermal hyoscine by adjunctive therapy with low dosage of pyridostigmine.

1. The value of low dosage of pyridostigmine (30 mg three times daily) in preventing peripheral anti-muscarinic side effects of a transdermal controlled-release formulation of hyoscine, was tested in a double-blind placebo-controlled study, involving 47 healthy subjects. 2. Salivary excretion was repeatedly measured during 48 h of combined therapy of two transdermal hyoscine patches with pyridostigmine and 14 h after its cessation. Blood acetylcholinesterase activity was also measured, serving as an index of pyridostigmine bioavailability. 3. The adjunctive therapy with pyridostigmine was highly effective in preventing the substantial impairment in salivary flow caused by the transdermal formulation. An associated 23% inhibition of blood acetylcholinesterase activity was observed. 4. Small doses of pyridostigmine may therefore have a role in increasing the tolerability of transdermal hyoscine therapy. In some patients this drug combination might also allow some increment of the hyoscine dose.

Acetylcholinesterase↗
PubMed1992

Continuous control of intraocular pressure in pseudophakic retinal detachment surgery.

We describe a method for continuous control of intraocular pressure in pseudophakic retinal detachment surgery done shortly after extracapsular cataract extraction and posterior chamber intraocular lens implantation. The system consists of a special needle inserted into the anterior chamber through the corneal limbus. The needle is attached by a regular intravenous administration set to an infusion bag. This allows fluids to exit the eye when the eyeball is compressed and to return to the eye when pressure on the eye is released. The presence of an intact posterior capsule and an intraocular lens do not impose a significant barrier to the passage of fluids between the anterior chamber and the vitreous cavity. Using this technique, intraocular pressure can be stabilized throughout the operation. The implementation of this system is demonstrated by a case report.

Cataract Extraction↗
PubMed1992

The protective effect of early intraoperative injection of viscoelastic material in trabeculectomy.

In a prospective study, we evaluated the effect of intracameral injection of sodium hyaluronate (HA) in trabeculectomy on short- and long-term results, including the effect on the corneal endothelium. Twenty-two patients were randomly assigned into two groups: group A, consisting of 11 patients, underwent standard trabeculectomy; in group B (11 patients), additionally, HA was injected into the anterior chamber immediately following paracentesis in an attempt to minimize shallowing of the chamber after the subsequent trabeculectomy. Both groups had comparable age distributions, preoperative intraocular pressures (IOPs), preoperative endothelial cell counts, postoperative IOPs after 3 months, and glaucoma medication indices. The reduction in the number of endothelial cells after 1 month was significantly greater in group A than in group B (16.1% vs 6.7%). Also, significantly more shallow anterior chambers occurred in group A (three eyes vs one eye). However, 1 day postoperatively, the average IOP was 16.4 mm Hg in group A, as compared with 25 mm Hg in group B. Thus, although HA, injected early in trabeculectomy, appeared to protect against corneal endothelial loss and flat anterior chamber, it also seemed to be associated with early IOP spikes.

Aged↗
PubMed1991

The intravitreal penetration of orally administered ciprofloxacin in humans.

To evaluate the penetration of ciprofloxacin, a new wide-spectrum oral antibiotic, into the vitreous, ciprofloxacin was administered orally to 21 patients who were scheduled to undergo vitreal surgery. Seven patients received 750 mg ciprofloxacin 4 hr before surgery (group I), seven patients received this dose 8 hr before surgery (group II), and seven patients received two 750-mg doses of oral ciprofloxacin every 12 hr. The last dose was administered 12 hr before surgery (group III). Vitreous and blood samples were collected simultaneously and assayed for ciprofloxacin concentrations by bioassay and high-performance liquid chromatography.

Administration, Oral↗