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Biomedical subjects

Teresa C Chen

Publications and source records attributed to Teresa C Chen.

At least 19 recordsLinked to original sources
PubMed2006

The course of glaucoma during pregnancy: a retrospective case series.

OBJECTIVE: To better understand the course of glaucoma during pregnancy in women with preexisting disease. METHODS: Retrospective case series of 28 eyes of 15 women with glaucoma followed up during pregnancy. Data were analyzed for age, race/ethnicity, medications, glaucoma type, intraocular pressure (IOP), and visual fields before, during, and after pregnancy. RESULTS: In 16 (57.1%) of 28 eyes, IOP was stable during pregnancy, with no progression of visual field loss. In 5 eyes (17.9%), visual field loss progressed during pregnancy, while IOP remained stable or increased. In 5 eyes (17.9%), IOP increased during pregnancy, but there was no progression of visual field loss. In 2 eyes (7.1%), data were inconclusive because of medication noncompliance and preexisting severe visual field loss. Glaucoma medications were used by 13 of 15 patients to control glaucoma during pregnancy. The classes of medications used most frequently were beta-blockers, alpha2-adrenergic agents, cholinergic agents, and topical carbonic anhydrase inhibitors. CONCLUSIONS: The course of glaucoma during pregnancy is variable, and women must be monitored closely during pregnancy. Medications may be necessary to control IOP and to prevent vision loss during pregnancy.

Adult↗
PubMed2006

Histologic correlation of in vivo optical coherence tomography images of the human retina.

PURPOSE: To correlate in vivo human retina optical coherence tomography (OCT)3 images with histology. DESIGN: Case series. METHODS: Linear OCT3 scans through the macula and optic nerve were obtained in three eyes of three patients who then underwent exenteration surgery for orbital cancers. OCT3 images were then correlated with histology. RESULTS: On histology, two eyes were normal, and one eye had dry macular degeneration. The plexiform layers on histology correlated with the green/yellow areas on the OCT3 scans, and the nuclear layers correlated with the black areas on the OCT3 scans. CONCLUSIONS: The authors are unaware of previous reports correlating histology to in vivo human retina OCT3 images. Our findings using human eyes are not different from previous animal studies, in that the plexiform layers are optically highly backscattering and the nuclear layers are not.

Aged↗
PubMed2005

Spectral domain optical coherence tomography: ultra-high speed, ultra-high resolution ophthalmic imaging.

OBJECTIVE: To introduce a new ophthalmic optical coherence tomography technology that allows unprecedented simultaneous ultra-high speed and ultra-high resolution. METHODS: Using a superluminescent diode source, a clinically viable ultra-high speed, ultra-high resolution spectral domain optical coherence tomography system was developed. RESULTS: In vivo images of the retina, the optic nerve head, and retinal blood flow were obtained at an ultra-high speed of 34.1 microseconds (ms) per A-scan, which is 73 times faster than commercially available optical coherence tomography instruments. Single images (B-scans) consisting of 1000 A-scans were acquired in 34.1 ms, allowing video rate imaging at 29 frames per second with an axial resolution of 6 mum. Using a different source in a slightly slower configuration, single images consisting of 500 A-scans were acquired in 34 ms, allowing imaging at 29 frames per second at an axial resolution of 3.5 microm, which is 3 times better than commercially available optical coherence tomography instruments. The amount of energy directed into the eye in both cases, 600 microW, is less than that of the Stratus OCT3 and is safe for intrabeam viewing for up to 8 hours at the same retinal location. CONCLUSION: Spectral domain optical coherence tomography technology enables ophthalmic imaging with unprecedented simultaneous ultra-high speed and ultra-high resolution.

Adult↗
PubMed2005

Brimonidine 0.15% versus apraclonidine 0.5% for prevention of intraocular pressure elevation after anterior segment laser surgery.

PURPOSE: To compare the efficacy and safety of brimonidine 0.15% with those of apraclonidine 0.5% in preventing intraocular pressure (IOP) elevations after anterior segment laser surgery. SETTING: Massachusetts Eye and Ear Infirmary, Glaucoma Service, Boston, Massachusetts, USA. METHODS: This double-masked randomized trial 80 eyes of 80 patients who had laser peripheral iridotomy, argon laser trabeculoplasty, or neodymium:YAG laser capsulotomy. Eyes received 1 drop of brimonidine 0.15% or apraclonidine 0.5% before laser surgery. Intraocular pressure, heart rate, and blood pressure were measured before laser surgery and at 1 hour, 3 hours, 24 hours, and 1 week after laser surgery. RESULTS: Before laser treatment, 41 patients received brimonidine 0.15% and 39 received apraclonidine 0.5%. Thirteen (31.7%) patients in the brimonidine group and 11 (28.2%) in the apraclonidine group had postoperative IOP elevations of 5 mm Hg or more (P = .5). Four patients (9.8%) in the brimonidine group and 3 (7.7%) in the apraclonidine group had IOP increases of 10 mm Hg or more (P = .5). There were no statistically significant changes in mean heart rate or blood pressure in either group except a slight reduction in diastolic blood pressure at 1 hour in the brimonidine group (-4.7 +/- 9.2 mm Hg) compared with that in the apraclonidine group (-0.1 +/- 9.1 mm Hg) (P = .01). No clinically significant side effects were noted in either group. CONCLUSION: A single preoperative drop of brimonidine 0.15% had similar efficacy and safety as apraclonidine 0.5% in preventing IOP elevations immediately after anterior segment laser surgery.

Adrenergic alpha-Agonists↗
PubMed2004

In vivo human retinal imaging by ultrahigh-speed spectral domain optical coherence tomography.

An ultrahigh-speed spectral domain optical coherence tomography (SD-OCT) system is presented that achieves acquisition rates of 29,300 depth profiles/s. The sensitivity of SD-OCT and time domain OCT (TD-OCT) are experimentally compared, demonstrating a 21.7-dB improvement of SD-OCT over TD-OCT. In vivo images of the human retina are presented, demonstrating the ability to acquire high-quality structural images with an axial resolution of 6 microm at ultrahigh speed and with an ocular exposure level of less than 600 microW.

Humans↗
PubMed2004

Aphakic glaucoma after congenital cataract surgery.

OBJECTIVE: To describe the largest series of patients who developed aphakic glaucoma after lensectomy for congenital cataracts. METHODS: A retrospective review was performed of all patients seen by a pediatric glaucoma specialist between October 1, 1970, and November 30, 2002. Patients with intraocular pressures greater than 25 mm Hg after lensectomy were studied. Patients with either conditions independently associated with glaucoma or any signs of glaucoma before lensectomy were excluded. RESULTS: We studied 170 eyes of 117 patients. The mean +/- SD follow-up period was 8.6 +/- 7.6 years. The most common cataract types were complete (40.8%) and nuclear (22.5%). For the lensectomies, 103 eyes underwent modern vitrectomy techniques, and 10 underwent older techniques. Lensectomies were performed in 80.6% of eyes before age 1 year. Onset of glaucoma after lensectomy was by 1 year in 37.1% of eyes, by 6 years in 75.9%, and by 33 years in 100%. Of eyes that had gonioscopy, 93.9% had open angles. Glaucoma surgery was needed in 57.1% of eyes. The median final visual acuity was 20/400. CONCLUSIONS: Most cases of aphakic glaucoma are of the open-angle type. Various risk factors are suggested, and the prognosis is guarded. Lifelong follow-up is needed to screen for glaucoma.

Aphakia, Postcataract↗
PubMed2004

Thickness and birefringence of healthy retinal nerve fiber layer tissue measured with polarization-sensitive optical coherence tomography.

PURPOSE: Thinning of the retinal nerve fiber layer and changes in retinal nerve fiber layer (RNFL) birefringence may both precede clinically detectable glaucomatous vision loss. Early detection of RNFL changes may enable treatment to prevent permanent loss of vision. Polarization-sensitive optical coherence tomography (PS-OCT) can provide objective information on RNFL thickness and birefringence. METHODS: PS-OCT scans around the optic nerve head (ONH) of two healthy young volunteers were made using 10 concentric circles of increasing radius. Both the mean RNFL thickness and mean retinal nerve fiber birefringence for each of 48 sectors on a circle were determined with data analysis. RESULTS: Both the RNFL thickness and birefringence varied as a function of sector around the ONH. The RNFL became thinner with increasing distance from the ONH. In contrast, the birefringence did not vary significantly as a function of radius. CONCLUSIONS: Birefringence of healthy RNFL is constant as a function of scan radius but varies as a function of position around the ONH, with higher thickness values occurring superior and inferior to the ONH. Measured double-pass phase retardation per unit depth around the ONH ranged between 0.10 and 0.35 deg/microm, equivalent to birefringences of 1.2 x 10(-4) and 4.1 x 10(-4) respectively, measured at a wavelength of 840 nm. Consequently, when a spatially constant birefringence around the ONH is assumed, the conversion of scanning laser polarimetry (SLP) phase-retardation measurements to RNFL thickness may yield incorrect values. The data do not invalidate the clinical value of a phase-retardation measurement, but affect the conversion of phase retardation to RNFL thickness.

Adult↗
PubMed2003

Biologic activity of cytotoxic T lymphocyte-associated antigen 4 antibody blockade in previously vaccinated metastatic melanoma and ovarian carcinoma patients.

A large number of cancer-associated gene products evoke immune recognition, but host reactions rarely impede disease progression. The weak immunogenicity of nascent tumors contributes to this failure in host defense. Therapeutic vaccines that enhance dendritic cell presentation of cancer antigens increase specific cellular and humoral responses, thereby effectuating tumor destruction in some cases. The attenuation of T cell activation by cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) further limits the potency of tumor immunity. In murine systems, the administration of antibodies that block CTLA-4 function inhibits the growth of moderately immunogenic tumors and, in combination with cancer vaccines, increases the rejection of poorly immunogenic tumors, albeit with a loss of tolerance to normal differentiation antigens. To gain a preliminary assessment of the biologic activity of antagonizing CTLA-4 function in humans, we infused a CTLA-4 blocking antibody (MDX-CTLA4) into nine previously immunized advanced cancer patients. MDX-CTLA4 stimulated extensive tumor necrosis with lymphocyte and granulocyte infiltrates in three of three metastatic melanoma patients and the reduction or stabilization of CA-125 levels in two of two metastatic ovarian carcinoma patients previously vaccinated with irradiated, autologous granulocyte-macrophage colony-stimulating factor-secreting tumor cells. MDX-CTLA4 did not elicit tumor necrosis in four of four metastatic melanoma patients previously immunized with defined melanosomal antigens. No serious toxicities directly attributable to the antibody were observed, although five of seven melanoma patients developed T cell reactivity to normal melanocytes. These findings suggest that CTLA-4 antibody blockade increases tumor immunity in some previously vaccinated cancer patients.

Abatacept↗
PubMed2002

Retrobulbar chlorpromazine injections for the management of blind and seeing painful eyes.

PURPOSE: To report the efficacy of primary retrobulbar chlorpromazine injections for the management of blind and seeing painful eyes. PATIENTS AND METHODS: Retrospective case series from three university hospitals was done. Twenty eyes of 20 patients with at least 3 months of follow-up are reported. Ten of these 20 eyes did not receive any other ophthalmic medications either 2 weeks before chlorpromazine injection or at any time point after injection. Treatment was considered successful if pain control lasted for at least 3 months, without the need for reinjection or enucleation. RESULTS: Sixteen of 20 (80.0%) eyes achieved successful pain control. There were no permanent complications in any patient. CONCLUSIONS: Retrobulbar chlorpromazine appears to be safe and effective for the management of pain in blind eyes.

Adolescent↗
PubMedDate not supplied

In vivo birefringence and thickness measurements of the human retinal nerve fiber layer using polarization-sensitive optical coherence tomography.

Glaucoma causes damage of the nerve fiber layer, which may cause loss of retinal birefringence. Therefore, PS-OCT is a potentially useful technique for the early detection of glaucoma. We built a fiber-based PS-OCT setup that produces real-time images of the human retina in vivo, coregistered with retinal video images of the location of PS-OCT scans. Preliminary measurements of a healthy volunteer show that the double-pass phase retardation per unit of depth of the RNFL is not constant and varies with location, with values between 0.18 and 0.37 deg/microm. A trend in the preliminary measurements shows that the nerve fiber layer located inferior and superior to the optic nerve head is more birefringent than the thinner layer of nerve fiber tissue in the temporal and nasal regions.

Adult↗
PubMedDate not supplied

Ahmed valve surgery for refractory pediatric glaucoma: a report of 52 eyes.

PURPOSE: To describe the results of Ahmed valve surgery for refractory pediatric glaucoma. PATIENTS AND METHODS: We performed a retrospective review of patients younger than 18 years of age who had Ahmed valve surgery from November 1994 to January 2003. Success was defined as a reduction of the intraocular pressure (IOP) to 22 mm Hg or lower with or without medications at the last two follow-up visits, no additional glaucoma surgery, and no visually significant complications. RESULTS: There were 52 eyes of 41 patients. The two most common diagnoses were congenital glaucoma (38.5%) and aphakic glaucoma (36.5%). The mean number of glaucoma surgeries before Ahmed valve implantation was 1.7 +/- 1.7. The mean age at the time of implantation was 4.9 +/- 6.5 years. The mean IOP decreased from 38.1 +/- 6.4 mm Hg to 20.7 +/- 8.2 mm Hg at last follow-up. The final visual acuity was improved or within one Snellen line in 81.5% of the eyes. Cumulative probabilities of success were 85.1%, 63.2%, 51.7%, and 41.8% at 1, 2, 3, and 4 years, respectively. The mean postoperative follow-up period or time to failure for all patients was 2.2 +/- 1.8 years (range, 3 months to 7.5 years). CONCLUSIONS: The Ahmed valve was found to be useful in the management of refractory pediatric glaucoma. Although our success rates were similar to those observed in adults, the rates of certain post-operative complications were different.

Adolescent↗