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Biomedical subjects

Christina M Fraser

Publications and source records attributed to Christina M Fraser.

9 recordsLinked to original sources
PubMed2006

Comparison of the magnitude and time course of macular thinning induced by different interventions for diabetic macular edema: implications for sequence of application.

PURPOSE: To determine estimates of the magnitude and time course of macular thinning induced by three interventions for diabetic macular edema (DME). DESIGN: Retrospective observational case series. PARTICIPANTS: Two hundred eleven eyes of 133 patients of a private retina practice, each diagnosed with DME in > or =1 eye. METHODS: Review of clinical charts and optical coherence tomography measurements of eyes receiving focal laser photocoagulation, intravitreal triamcinolone injection (IVTA), or vitrectomy compared to untreated fellow eyes without DME. MAIN OUTCOME MEASURES: Central subfield mean thickness (CSMT; in micrometers), total macular volume (cubic millimeters), visual acuity, and rates of increased macular thickening at follow-up. RESULTS: At 6 months follow-up, predicted change in CSMT is 0 mum for untreated fellow eyes without DME, -28 mum for eyes receiving focal laser, -83 mum for eyes receiving triamcinolone, and -92 mum for eyes receiving vitrectomy. The predicted change in Early Treatment Diabetic Retinopathy Study letters read at 6 months is 0 for untreated fellow eyes without DME, 0 for eyes receiving focal laser, +3 for eyes receiving IVTA, and -1 for eyes receiving vitrectomy. Increased thickening of the macula after interventions designed to thin it were 25.4% for focal laser, 3.8% for IVTA, and 19.0% for vitrectomy. CONCLUSIONS: Interventions for DME differ in effect size, durability of effects, and potential for subsequent increases in macular thickness. A prospective study to elucidate a preferred sequence of interventions in DME may be worthwhile.

Diabetic Retinopathy↗
PubMed2005

Clinical management of silicone intraocular lens condensation.

PURPOSE: To report a novel technique in the management of silicone intraocular lens condensation after gas-fluid exchange. DESIGN: Interventional case report. METHODS: Clinical management of an obstacle to treatment. setting: Private retina practice. patient population: One patient with silicone posterior chamber intraocular lens implant and posterior capsulotomy who subsequently experienced complicated retinal detachment. intervention: Application of a heating pad to clear intraocular lens condensation. main outcome measure: Visibility of the fundus for laser treatment. RESULTS: Application of a heating pad to the closed eyelid significantly reduced the intraocular lens condensation and provided a clear view for the surgeon to apply laser retinopexy. CONCLUSIONS: Treatment of retinal detachment is complicated by lens condensation after gas-fluid exchange in patients who have undergone silicone posterior chamber intraocular lens implantation and posterior capsulotomy. We report a simple, inexpensive, and effective method to reduce lens condensation and enable in-office examination and laser treatment.

Aged↗
PubMed2005

Regional patterns of sight-threatening diabetic macular edema.

PURPOSE: To define regional patterns of macular thickening in diabetic macular edema (DME). DESIGN: Retrospective case series. METHODS SETTING: Retina practice. PATIENT POPULATION: Fifty-two normal eyes of 48 patients and 100 eyes of 80 patients with DME. EXPERIMENTAL PROCEDURE: We measured retinal thickness for nine zones and total macular volume using the 3.5-mm display of an optical coherence tomograph (OCT). We determined the normal ranges of values for zones, and then normal ranges of values for the difference in thickness between each pair of zones, termed comparisons. main outcome measures: Frequencies of increased zonal thickness, increased total macular volume, and abnormalities in zonal comparisons. RESULTS: We found the following abnormalities: increased total macular volume 49% (49/100), increased foveal zone thickness 46% (46/100), increased inner parafoveal zone thickness (average 42.2% for the four zones), and increased outer zone thickness (average 34.3% for the four zones). Abnormal two-zone comparisons were found in 1027 of the 7200 possible comparisons (14.3%). Of these abnormal comparisons, the fovea was thicker relative to another zone in 26%; the four inner parafoveal zones were thicker relative to other zones in 8.7% to 15.2% (average 13.0%); and the four outer zones were thicker relative to other zones in 3.9% to 7.6% (average 6%). Eighty-eight percent (88/100) of the eyes chosen on clinical grounds as needing focal laser photocoagulation were detected. CONCLUSION: A broader concept of OCT abnormality, which includes abnormalities in zonal relationships, may improve automated detection of DME compared with clinical judgment.

Adult↗
PubMed2005

Ocular conditions associated with peripapillary subretinal neovascularization, their relative frequencies, and associated outcomes.

OBJECTIVE: To determine frequency and outcomes of conditions with peripapillary subretinal neovascular membranes (PSRNVMs). DESIGN: Retrospective observational case series. PARTICIPANTS: All patients from a private community-based retina practice diagnosed with a PSRNVM. METHODS: Review of clinical charts, photographs, and fluorescein angiograms of 115 eyes of 96 patients, accrued over 18 years. MAIN OUTCOME MEASURES: Demographics, visual acuity (VA), laterality, neovascular membrane type and recurrence status over treatment course, and associated ocular conditions. RESULTS: Prevalences of reported associations were 52 (45.2%), age-related maculopathy (ARM); 45 (39.1%), idiopathic; 5 (4.3%), multifocal choroiditis; 3 (2.6%), angioid streaks; 2 (1.7%), histoplasmosis; 2 (1.7%), choroidal osteoma; 1 (0.9%), optic disc drusen; and 1 (0.9%), congenital disc anomaly. Newly recognized associations include pattern dystrophy (3 [2.6%]) and peripapillary pseudopodal pigment epithelial and choroidal atrophy (1 [0.9%]). Second-eye involvement was observed in 19.8% of patients over a median follow-up of 2 years. Median initial VAs were 20/40 for ARM-associated eyes and 20/30 for idiopathic eyes (P = 0.0230). Median final VAs were 20/70 for ARM-associated eyes and 20/32 for idiopathic eyes (P = 0.0261). The VA changes in the ARM-associated and idiopathic groups did not differ significantly (P = 0.1453). Recurrence of PSRNVMs after laser ablation was seen in 14 of 73 eyes (19.2%). A case of a PSRNVM as a cause of pseudopapilledema leading to unnecessary neurological imaging is reported. CONCLUSIONS: Close inspection of fellow eyes at the time of first eye diagnosis and regular follow-up afterward are indicated, given the high rate of eventual bilateral involvement regardless of associated condition. Laser ablation of PSRNVMs with broad treatment margins reduces recurrence rates relative to earlier series. The differential diagnosis of disc edema should include PSRNVMs. Pattern dystrophy can be associated with PSRNVMs.

Adult↗
PubMed2004

Optical coherence tomography to detect macular edema in the presence of asteroid hyalosis.

PURPOSE: To propose the use of optical coherence tomography as an effective diagnostic tool for identifying macular edema in patients with asteroid hyalosis obscuring the fundus view. DESIGN: Case report. METHODS: Review of clinical chart and images. SETTING: Private retina practice. PATIENT: One patient diagnosed with diabetic retinopathy and asteroid hyalosis, who was experiencing decreased visual acuity and whose fundus view was inadequate for diagnosis using customary techniques. RESULTS: Usual methods of diagnosis were ineffective until OCT obtained a clear image of the fundus and subsequent macular thickening with vitreomacular adhesion. CONCLUSIONS: Optical coherence tomography is an effective diagnostic tool for discovering macular edema in cases of dense asteroid hyalosis where traditional methods fail to obtain a clear image of the fundus.

Aged↗
PubMed2004

Intraobserver variability in optical coherence tomography.

PURPOSE: To assess the intraobserver variability of optical coherence tomography (OCT) in patients with clinically stable maculas. DESIGN: Retrospective, observational case series using a diagnostic instrument. METHODS: Retrospective study. setting. Private retina practice. patient population. Twenty-two eyes of 19 patients, each studied twice within 4 months. observation procedure. Optical coherence tomograph measurements of the macula obtained by two photographers. main outcome measures. Ordinary least products (OLP) and Bland-Altman analysis of OCT data. RESULTS: No fixed or proportional bias was detected in foveal zone thickness and total macular volume between measurements of either of the OCT operators. The coefficient of repeatability for foveal zone thickness was 37.0 microm for photographer 1 and 34.8 microm for photographer 2. The coefficient of repeatability for total macular volume was 0.29 mm(3) for photographer 1 and 0.10 mm(3) for photographer 2. CONCLUSION: Foveal zone thickness and total macular volume measurements show low intraobserver variability when analyzed by OLP and Bland-Altman techniques. Bounds are given for foveal zone thickness and total macular volume for which longitudinal OCT measurements by the same operator can be considered to reflect natural history or intervention effects rather than intraobserver variability.

Diagnostic Techniques, Ophthalmological↗
PubMed2004

Retinal vein occlusions in patients taking warfarin.

OBJECTIVE: To describe development of retinal vein occlusion (RVO) in patients anticoagulated with warfarin. DESIGN: Retrospective, observational case series. PARTICIPANTS: Thirteen patients drawn from a private retina practice. METHODS: Review of clinical records, laboratory results, color fundus photographs, and fluorescein angiograms. MAIN OUTCOME MEASURES: Primary measures were international normalized ratio (INR), visual acuity, and concurrent systemic disease. RESULTS: The female-to-male ratio was 7 to 6. Age range was 44 to 86 years, with a median age of 73 years. Two patients had systemic lupus erythematosus, 7 had hypertension, and 2 had primary open-angle glaucoma. Two had laboratory abnormalities: 1 with a combination of lupus anticoagulant and anticardiolipin antibodies and 1 with a combination of hyperhomocystinemia and low antithrombin III. Three patients were taking acetylsalicylic acid in addition to warfarin at the time of the RVO. The INRs at the time of RVO were 0.9 to 3.8, with 9 of 13 <==2.0. CONCLUSIONS: Anticoagulation with warfarin does not preclude RVO in predisposed patients, nor does combination therapy with warfarin and acetylsalicylic acid. Attention to keeping the INR >2.0 may be helpful.

Adult↗
PubMedDate not supplied

A spreadsheet template for the analysis of optical coherence tomography in the longitudinal management of diabetic macular edema.

BACKGROUND AND OBJECTIVE: To provide a tool for analyzing optical coherence tomography data in patients with diabetic macular edema. PATIENTS AND METHODS: Retrospective series of 206 patients with diabetic macular edema involving at least one eye and receiving focal laser photocoagulation, intravitreal triamcinolone acetonide injection, or vitrectomy, membrane peeling, and intravitreal triamcinolone acetonide injection, and of untreated fellow eyes without diabetic macular edema. Main outcome measures included foveal subfield mean thickness and thickening relative to normal (microns), total macular volume and its increase relative to normal (mm3), visual acuity (Snellen decimal), and intraocular pressure (mm Hg). RESULTS: The authors demonstrate a graphical display of data based on a spreadsheet template for the longitudinal management of diabetic macular edema. Complex relationships of ocular response and interventions are concisely displayed. CONCLUSION: A graphical display of optical coherence tomography, visual acuity, and intraocular pressure data is a practical aid in the management of diabetic macular edema.

Computer Graphics↗