Search PubMed⌕ Search

Biomedical subjects

T R Friberg

Publications and source records attributed to T R Friberg.

At least 19 recordsLinked to original sources
PubMed2001

Infrared micropulsed laser treatment for diabetic macular edema--subthreshold versus threshold lesions.

PURPOSE: To assess the effectiveness of subthreshold (invisible after placement) and threshold (barely visible after placement) 810nm laser photocoagulation in the treatment of clinically significant diabetic macular edema. METHODS: A grid of subthreshold laser spots was used to treat patients with diabetic edema. Retrospectively, the results of treatment of 20 eyes of 20 patients were compared to the results of treatment of 120 eyes of 120 patients using a grid of threshold laser lesions. RESULTS: At six months, 60% of subthreshold treated eyes and 75% of threshold treated eyes showed anatomic resolution of macular edema. Improvement or stabilization of visual acuity was achieved in 85% of threshold or subthreshold treated eyes. CONCLUSION: Gentle grid treatment of regions of diabetic macular edema was effective in ameliorating the edema and limiting visual loss. Subthreshold laser was less effective in promoting resolution of edema compared to threshold lesions, though the difference was not significant in this instance.

Chi-Square Distribution↗
PubMed2001

Transpupillary thermotherapy (TTT) for age-related macular degeneration.

PURPOSE: To review the results of transpupillary thermotherapy (TTT) on choroidal neovascular membranes associated with age-related macular degeneration (AMD). MATERIALS AND METHODS: 35 eyes of 35 patients with AMD and choroidal neovascularization and exudation were treated with TTT and had fundus photographs and fluorescein angiography (FA) before and at least six months after TTT. 28 eyes had predominantly occult lesions as seen on FA, while 7 demonstrated primarily classic lesions. All were treated with 650mw power or less using the 810 nm diode laser (3000 micron spot, duration of 60 seconds). Visual acuity, lesion size, and amount of subretinal fluid were determined by results of examination and review of photographs and fluorescein angiograms. RESULTS: A 50% reduction in subretinal fluid was achieved in 67% of treated eyes overall, with stabilization of vision (less than three lines of visual acuity lost) in 86%. Complications from treatment were infrequent (9%) and involved hemorrhage noted in the region of treatment upon follow-up. CONCLUSION: TTT promotes resolution of subretinal fluid and appears to stabilize visual acuity in patients with exudative AMD.

Choroidal Neovascularization↗
PubMed2000

Migration of silicone oil into the brain: a complication of intraocular silicone oil for retinal tamponade.

PURPOSE: To report a case in which intravitreal silicone oil migrated along the intracranial portion of the optic nerve and into the lateral ventricles of the brain after the repair of a retinal detachment secondary to cytomegalovirus retinitis. METHODS: A 42-year-old man with acquired immunodeficiency syndrome (AIDS) developed a rhegmatogenous retinal detachment in his left eye secondary to a cytomegalovirus infection of the retina. The detachment was repaired using 5000 cs intraocular silicone oil for a long-term tamponade. Subsequently, the affected eye developed glaucoma, which was poorly controlled. Fifteen months after the retinal surgery, he developed a peripheral neuropathy that was thought to be AIDS related. Computed tomography and magnetic resonance imaging of the head were performed to investigate the neuropathy. RESULTS: The patient was found to have a foreign substance within his lateral ventricles that shifted with position and was identical with respect to its imaging properties to the remaining intraocular silicone oil. Additional material was found along the intracranial portion of his optic nerve. CONCLUSION: Under certain circumstances, intraocular silicone oil may migrate out of the eye, along the intracranial portion of the optic nerve, and into the lateral ventricles of the brain.

AIDS-Related Opportunistic Infections↗
PubMed2000

Diminished perception of ambient light: a symptom of clinical depression?

OBJECTIVE: In a non-randomized, uncontrolled pilot study, the authors investigated whether depressed patients were more likely to perceive the lighting in their environment as being dimmer than usual. METHOD: 120 patients (46 males, 74 females) who presented for possible admission for depression at a psychiatric facility were administered a Diagnostic and Statistical Manual of disorders (DSM-IV) based questionnaire and underwent psychiatric evaluation. A question asking whether 'the lights in my surroundings seem dimmer than usual' was included in the 15-point question survey. Statistical analyses were performed to determine whether an affirmative response to this dimness question was correlated with the depth of depression (mild, moderate, severe) and also whether significant correlation was present between the percentage of patients answering yes to the dimness question versus the number of yes responses to the core symptoms of depression. RESULTS: Two thirds of the patients categorized as severely depressed responded that their ambient environment appeared dimmer than usual compared to 21% of moderately and 14% of mildly depressed patients. This difference was statistically significant (P<0.05). The degree of depression as determined by the number of core questions answered affirmatively and the presence of this 'dimness' symptom were highly correlated (P=0.002, R=0.87). LIMITATIONS: The specificity of the finding has not been tested in reference to non-affective psychiatric patient groups. CONCLUSION: A patient's perception of the ambient light in the environment being dimmer than usual may be an important symptom of a major depressive disorder. Further replication and objective testing of visual function in depressed patients appears warranted.

Adult↗
PubMed1999

Therapeutic benefits of infrared (810-nm) diode laser macular grid photocoagulation in prophylactic treatment of nonexudative age-related macular degeneration: two-year results of a randomized pilot study.

OBJECTIVE: This pilot study collected preliminary information on the effectiveness and safety of infrared (810-nm) diode laser macular grid photocoagulation in patients with nonexudative age-related macular degeneration (AMD). Results from this pilot study were used in designing a larger, multicenter, randomized clinical trial. DESIGN: A multicenter, randomized, controlled, clinical trial. PARTICIPANTS: A total of 229 eyes of 152 patients with AMD were enrolled in the pilot study. Seventy-five patients with 1 eye eligible (75 eyes) were enrolled in the unilateral arm of the study; 77 patients with both eyes eligible (154 eyes) were enrolled in the bilateral arm of the study. In the unilateral study arm, 32 eyes were randomized to the observation group, 27 eyes were treated with visible endpoint burns, and 16 eyes were treated with invisible endpoint (subthreshold) lesions. In the bilateral study arm, 77 eyes were in the observation group, 36 eyes were treated with visible burns, and 41 eyes were treated with subthreshold (invisible) lesions. INTERVENTION: Eyes were treated with infrared (810-nm) diode laser macular grid photocoagulation using either visible burns or subthreshold (invisible) lesions and compared to eyes receiving no treatment. MAIN OUTCOME MEASURES: Reduction of drusen, change in visual acuity, and rate of choroidal neovascularization (CNV) membrane formation. RESULTS: At 12 months after treatment, 62% of eyes treated with visible burns had a clinically significant reduction in drusen, whereas this proportion (65%) was reached in 18 months for eyes treated with subthreshold lesions. At 24 months' follow-up, treated eyes had a significant reduction in drusen compared to observation eyes (P < 0.0001). Visual acuity was significantly improved in treated eyes at 12, 18, and 24 months compared to observation eyes (P < 0.001). Choroidal neovascularization formation was similar in treated and observation eyes through 24 months' follow-up. Complications included CNV associated with six eyes treated with visible burns and a juxtafoveal laser scar in one eye treated with visible burns. CONCLUSIONS: Infrared (810-nm) diode laser macular grid photocoagulation in patients with nonexudative AMD significantly reduces drusen levels (P < 0.0001) and significantly improves visual acuity (P < 0.001) when either visible endpoint burns or subthreshold endpoint lesions are used. Complications were fewer using subthreshold endpoint lesions. A larger, multicenter, prospective clinical trial with longer follow-up is needed to determine the efficacy of treatment in reducing the rate of CNV formation. Data from this clinical pilot study have been used to design the Prophylactic Treatment of AMD Trial (PTAMD), a multicenter, randomized, prospective clinical trial currently in progress comparing subthreshold (invisible) treatment to observation in eyes with nonexudative AMD.

Aged↗
PubMed1999

Laser photocoagulation of eyes with drusen: will It help?

Drusen are deposits located deep in the sensory retina that are seen characteristically in eyes with macular degeneration (AMD). As multiple large drusen are a risk factor for the development of visual loss from AMD, laser strategies to cause drusen to resorb have been devised. Two large, randomized controlled trials using laser photocoagulation prophylactically for the treatment of AMD are underway to determine the efficacy of such treatment.

Clinical Trials as Topic↗
PubMed1997

The treatment of macular disease using a micropulsed and continuous wave 810-nm diode laser.

OBJECTIVE: The purpose of the study is to determine whether the 810-nm diode wavelength using a rectangular waveform is clinically effective in the treatment of choroidal neovascularization from age-related macular degeneration and to determine whether macular edema secondary to branch vein occlusion or diabetic retinopathy can be effectively treated with this laser using the micropulse waveform. DESIGN: Review of consecutive nonrandomized patients whose eyes were treated with the diode laser over a 30-month period. PARTICIPANTS: Fifty-three patients with an initial presentation of choroidal neovascularization located subfoveally (77%), extrafoveally (17%), and juxtafoveally (6%); 14 patients with macular edema from a branch vein occlusion; and 59 patients with diabetic macular edema, 40 of which were treated for the first time. INTERVENTION: Ablative rectangular wave laser photocoagulation was applied to the choroidal neovascular membranes and very light threshold treatment was applied in a macular grid to treat retinal edema. Microaneurysms were not targeted. MAIN OUTCOME MEASURES: Anatomic resolution of macular edema or choroidal neovascularization and visual acuity. RESULTS: Sixty percent of eyes treated for choroidal neovascularization had no persistence or recurrence at 6 months, and 72% achieved visual stabilization. In 8% of eyes, some localized bleeding occurred during photocoagulation. Clinical resolution of macular edema from branch vein occlusion occurred by 6 months in 92% of eyes, and 77% had stabilization of visual acuity. At 6 months, 76% of newly treated patients with diabetic macular edema and 67% of previously treated patients had clinical resolution of their edema. Vision was improved or stabilized in 91% and 73% of newly treated and retreated patients at 6 months, respectively. CONCLUSIONS: The micropulsed 810-nm diode laser is clinically effective in the treatment of macular edema from venous occlusion and diabetic retinopathy, and the rectangular (normal) mode diode laser can be used in many eyes with choroidal neovascularization.

Aged↗
PubMed1995

Sudden visual loss associated with sexual activity.

OBJECTIVE: To characterize the ocular fundus findings of patients who suffered sudden visual loss associated with sexual activity. DESIGN: Case series. SETTING: Outpatient ophthalmic practice. PATIENTS: Six patients presented with a precipitous decrease in vision in one eye with no apparent predisposing factors. After obtaining a careful history, each patient revealed that he or she had been engaging in rigorous sexual activity immediately before experiencing the visual loss. INTERVENTION: Five of the six patients were followed up without intervention. One patient required prophylactic laser photocoagulation of a retinal tear to decrease the risk of retinal detachment. RESULTS: Six patients aged 24 to 53 years suffered sudden loss of vision secondary to intraretinal, preretinal, or vitreous hemorrhaging. Visual acuity in the affected eyes ranged from a mild decrease (20/40) to profound visual loss (counting fingers at 6 in). Five of the six patients were followed up for at least 1 month and showed spontaneous improvement in vision as the blood cleared. Those who returned for long-term follow-up enjoyed complete visual recovery without any sequelae. CONCLUSIONS: Sudden debilitating visual loss may occur during sexual activity from the rupture of retinal blood vessels in the macular region or from the development of vitreous bleeding from an induced retinal tear. The long-term prognosis after such hemorrhaging appears to be excellent, with good visual recovery occurring as the blood resorbs spontaneously.

Adult↗
PubMed1995

Alteration of pulse configuration affects the pain response during diode laser photocoagulation.

BACKGROUND AND OBJECTIVE: The shape of the treatment pulse of the diode laser (810 nm) can be easily altered electronically in contrast to ion laser photocoagulators. We investigated whether changes in laser pulse shape influenced the subjective pain responses in patients undergoing retinal photocoagulation when only topical anesthesia was used. STUDY DESIGN/MATERIALS AND METHODS: Twenty consecutive patients required peripheral retinal photocoagulation for proliferative diabetic retinopathy or extensive retinal breaks. Three diode pulse waveforms including a square wave, shaped-wave, and an envelope of micropulses were compared to one another. Power was adjusted so that each waveform delivered the same total energy. The patients subjectively ranked the intensity of any pain they experienced for each group of lesions. Responses were compared to one another using an analysis of variance. RESULTS: 40% of patients found the standard square wave pulse to be significantly more painful (P < 0.05) than the shaped pulse mode and 30% found the square wave significantly more painful (P < 0.05) than the micropulse mode. CONCLUSION: Modification of the laser pulse waveform may ameliorate pain induced by diode laser photocoagulation of the retinal periphery.

Analysis of Variance↗
PubMed1995

Lens-sparing vitrectomy with perfluorocarbon liquid for the primary treatment of giant retinal tears.

PURPOSE: To evaluate the surgical success of vitrectomy without initial lensectomy in the primary treatment of retinal detachment associated with giant tears without proliferative vitreoretinopathy. METHODS: Thirty-four consecutive phakic eyes with idiopathic giant retinal tears underwent vitrectomy, injection of perfluorocarbon liquid, endolaser, and gas tamponade. Encircling scleral buckling was performed in 14 of 34 patients. Preoperative visual acuity ranged from 20/25 to hand motions. Giant tear size ranged from 90 degrees to 330 degrees. Follow-up ranged from 10 to 64 months. RESULTS: Anatomic retinal re-attachment was achieved intraoperatively in all eyes. The re-operation rate was 14% for eyes that underwent scleral buckling with the initial vitrectomy and 45% in eyes without primary scleral buckling. In 59% of eyes with cataract formation, 32% underwent cataract surgery with or without intraocular lens implantation. Best-corrected final visual acuity ranged from 20/15 to 20/400. CONCLUSION: Most phakic eyes with giant retinal tear not associated with proliferative vitreoretinopathy can be re-attached successfully with initial preservation of the lens.

Adolescent↗
PubMed1995

Antihistamines reduce blood-retinal barrier permeability in type I (insulin-dependent) diabetic patients with nonproliferative retinopathy. A pilot study.

PURPOSE: To determine if histamine receptor stimulation mediates increased blood-retinal barrier (BRB) permeability in patients with diabetic retinopathy, as it does in experimental diabetes. METHODS: Fourteen patients with type I (insulin-dependent) diabetes and mild nonproliferative diabetic retinopathy were treated with combined astemizole, 20 mg, and ranitidine, 600 mg, or an identical placebo for 6 months in a double-masked fashion. Blood-retinal barrier permeability was measured by vitreous fluorometry at baseline and at 3 and 6 months. RESULTS: Permeability was significantly reduced in the group treated with antihistamines (P < 0.05) compared with the placebo group. There were no concomitant significant changes in systemic arterial blood pressure or HbA1c values. CONCLUSION: These pilot data suggest that histamine receptors influence permeability of the BRB in human diabetes. Further studies of the effects of antihistamines on diabetic retinopathy are warranted.

Adult↗
PubMed1993

Vitreous cultures in suspected endophthalmitis. Biopsy or vitrectomy?

BACKGROUND: Isolation of bacteria from vitreous biopsy often guides therapy in suspected endophthalmitis. Therapeutic vitrectomy provides an additional source of culture material. The authors compared the ability of these two techniques to isolate organisms from patients with acute endophthalmitis. METHODS: In a large ophthalmic microbiology laboratory during a 4-year period, the authors analyzed 206 microbial culture results from patients with suspected endophthalmitis. RESULTS: Two hundred six cases were evaluated. While cultures of vitreous biopsy specimens obtained using a needle and syringe were positive in 91 (53.8%) of 169 patients, culturing the contents of the vitrectomy cassettes produced positive cultures in 29 (74.8%) of 39 patients. Both techniques were performed on 23 patients. Vitreous biopsy allowed isolation of the causative organism in 43% of these patients, whereas vitrectomy was 76% successful. Both comparisons were significant at the P < 0.01 level. No positive vitreous biopsy cultures had associated negative vitrectomy cultures. CONCLUSION: Culturing the contents of the vitrectomy cassette significantly increases the likelihood of obtaining a positive culture compared with merely culturing a vitreous biopsy.

Acute Disease↗