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Biomedical subjects

C A Puliafito

Publications and source records attributed to C A Puliafito.

At least 37 records · Page 2Linked to original sources
PubMed1995

Optical coherence tomography of central serous chorioretinopathy.

PURPOSE: To assess the potential of a new imaging technique, optical coherence tomography, for the diagnosis and monitoring of central serous chorioretinopathy. Optical coherence tomography is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution, cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound, except that it uses light rather than sound to obtain higher image resolution in the retina. Cross-sectional tomographs of optical reflectivity within the retina are produced with longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 16 patients at a referral eye center whose initial examination disclosed the clinical diagnosis of central serous chorioretinopathy. The optical coherence tomography results were correlated with slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by optical coherence tomography was effective in objectively quantifying the amount of serous retinal detachment in the disease. Optical coherence tomography disclosed detachments that were undetected by slit-lamp biomicroscopy. Longitudinal measurements with optical coherence tomography were successfully able to track the resolution of subretinal fluid accumulation. CONCLUSION: Optical coherence tomography is potentially useful as a new, noninvasive diagnostic technique for quantitative examination of patients with central serous chorioretinopathy and objectively monitoring the clinical course of the serous retinal detachment in this disease.

Adult↗
PubMed1995

Indocyanine green angiography and choroidal neovascularization obscured by hemorrhage.

BACKGROUND AND OBJECTIVE: To determine the use of indocyanine green (ICG) angiography in detecting choroidal neovascularization obscured by hemorrhage. STUDY/DESIGN: Indocyanine green angiography was performed on 20 consecutive patients who were suspected to have choroidal neovascular membranes (CNVs) that were obscured by subretinal or intraretinal hemorrhage on fluorescein angiography. The etiology of choroidal neovascularization was age-related macular degeneration. RESULTS: In all patients, ICG angiography was able to detect some choroidal neovascularization. The entire extent of the CNV was identified in 12 (60%) of these patients after ICG angiography was performed. In the remaining eight eyes (40%), the CNV still was obscured partially by a thick layer of hemorrhage. Difficulty in detection was due to thick subretinal hemorrhage, lipid exudate, and pigment. CONCLUSION: The authors conclude that ICG angiography is superior to fluorescein angiography in showing the presence and extent of CNVs associated with age-related macular degeneration that are almost entirely obscured by hemorrhage.

Choroid↗
PubMed1995

Optical coherence tomography of macular holes.

PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography (OCT) for diagnosing and monitoring macular holes. This technique is a novel noninvasive, noncontact imaging modality that produces high longitudinal resolution (10-micron) cross-sectional tomographs of ocular tissue. METHODS: Optical coherence tomography is analogous to ultrasound except that optical rather than acoustic reflectivity is measured. Cross-sectional tomographs of the retina profiling optical reflectivity in a thin, optical slice of tissue are obtained with a longitudinal resolution of 10 microns. Optical coherence tomography was used to examine 49 patients with the clinical diagnosis of idiopathic full-thickness macular hole, impending macular hole, epimacular membrane with macular pseudohole, or partial-thickness hole. The resulting OCTs were correlated with contact lens and slit-lamp biomicroscopy, fundus photography, and fluorescein angiography. RESULTS: The cross-sectional view produced by OCT was effective in distinguishing full-thickness macular holes from partial-thickness holes, macular pseudoholes, and cysts. Optical coherence tomography was successful in staging macular holes and provided a quantitative measure of hole diameter and the amount of surrounding macular edema. Optical coherence tomography also was used to evaluate the vitreoretinal interface in patients' fellow eyes and was able to detect small separations of the posterior hyaloid from the retina. CONCLUSION: Optical coherence tomography appears potentially useful as a new, noninvasive, diagnostic technique for visualizing and quantitatively characterizing macular holes and assessing fellow eyes of patients with a macular hole. The tomographic information provided by OCT eventually may lead to a better understanding of the pathogenesis of macular hole formation.

Adult↗
PubMed1995

The digital indocyanine green videoangiography characteristics of well-defined choroidal neovascularization.

PURPOSE: To evaluate the digital indocyanine green (ICG) videoangiography characteristics of well-defined choroidal neovascularization (CNV). METHODS: The authors retrospectively reviewed all ICG angiograms performed at the New England Eye Center over a 2-year period. Included in this study were all patients with the clinical and fluorescein angiographic diagnosis of well-defined CNV according to the Macular Photocoagulation Study Group criteria. RESULTS: Of the 25 eligible patients, 18 (72%) had a well-demarcated area of ICG hyperfluorescence that was observed either both early and late (6 patients = 24%) or only late (12 patients = 48%) on the ICG angiogram. Five patients (20%) showed only poorly demarcated late hyperfluorescence on ICG angiography. Two patients (8%) had type II occult CNV associated with classic CNV as per the Macular Photocoagulation Study Group criteria. Both patients showed a late, well-demarcated area of ICG hyperfluorescence greater than the area imaged with fluorescein angiography. CONCLUSIONS: Choroidal neovascularization which is well-defined on fluorescein angiography has variable ICG appearances. When there is late leakage associated with a well-defined CNV on fluorescein angiography (type II occult CNV), ICG angiography may more completely delineate the extent of the lesion.

Aged↗
PubMed1995

Imaging of macular diseases with optical coherence tomography.

BACKGROUND/PURPOSE: To assess the potential of a new diagnostic technique called optical coherence tomography for imaging macular disease. Optical coherence tomography is a novel noninvasive, noncontact imaging modality which produces high depth resolution (10 microns) cross-sectional tomographs of ocular tissue. It is analogous to ultrasound, except that optical rather than acoustic reflectivity is measured. METHODS: Optical coherence tomography images of the macula were obtained in 51 eyes of 44 patients with selected macular diseases. Imaging is performed in a manner compatible with slit-lamp indirect biomicroscopy so that high-resolution optical tomography may be accomplished simultaneously with normal ophthalmic examination. The time-of-flight delay of light backscattered from different layers in the retina is determined using low-coherence interferometry. Cross-sectional tomographs of the retina profiling optical reflectivity versus distance into the tissue are obtained in 2.5 seconds and with a longitudinal resolution of 10 microns. RESULTS: Correlation of fundus examination and fluorescein angiography with optical coherence tomography tomographs was demonstrated in 12 eyes with the following pathologies: full- and partial-thickness macular hole, epiretinal membrane, macular edema, intraretinal exudate, idiopathic central serous chorioretinopathy, and detachments of the pigment epithelium and neurosensory retina. CONCLUSION: Optical coherence tomography is potentially a powerful tool for detecting and monitoring a variety of macular diseases, including macular edema, macular holes, and detachments of the neurosensory retina and pigment epithelium.

Adult↗
PubMed1995

Optical coherence tomography: a new tool for glaucoma diagnosis.

Optical coherence tomography (OCT) is a novel technique that allows cross-sectional imaging of the anterior and posterior eye. OCT has a resolution of approximately 10 microns, with extremely high sensitivity (approximately 10(-10) of incident light). OCT is analogous to computed tomography, which uses x-rays, magnetic resonance imaging, which uses spin resonance, or B-scan ultrasound, which uses sound waves, but OCT uses only light to derive its image. OCT is a noncontact, noninvasive system by which retinal substructure may be analyzed in vivo. OCT is useful in the evaluation of retinal pathologies and glaucoma. In retinal disease, entities such as macular holes, macular edema, central serous chorioretinopathy, retinal vascular occlusion and other factors have been examined. Separation between the posterior vitreous and retina, or lack thereof, are seen and quantitated. In glaucoma, retinal nerve fiber layer (NFL) thickness is measured at standardized locations around the optic nerve head. A circular scan produces a cylindrical cross-section of the retina, from which the NFL can be analyzed. In addition, radial scans through the optic nerve head are used to evaluate cupping and juxtapapillary NFL thickness. OCT, a new imaging technology by which the anterior and posterior segment are seen in cross-section, may permit the early diagnosis of glaucoma, and the early detection of glaucomatous progression.

Anterior Eye Segment↗
PubMed1995

[Reflection measurement during retinal laser coagulation in patients. Development of an automatically controlled dosimeter].

PURPOSE: Retinal laser coagulation has limited reproducibility, because every laser exposition is unpredictably affected by pigmentation and media opacities. This can lead to complications. A feedback-controlled dosimeter would make retinal laser treatment a safer, more reproducible and faster procedure. METHOD: A reflectometer was developed that allows monitoring of the reflection of laser light during standard photocoagulation. Hundreds of coagulations in rabbit eyes and about 12,000 coagulations in patients undergoing routine laser treatment were recorded. RESULTS: The results of the first reflectance measurements in humans are presented along with extensive animal studies. A typical reflectance history was found for different lesion intensities. The degree of retinal whitening correlates with reflectance characteristics. These characteristics allow an early prediction of lesion intensity. Motion during laser exposure affects each coagulation in a fashion similar to spot size and exposure time. CONCLUSION: Reflectometry is the currently most effective means of monitoring lesion development. An automatic dosimeter for retinal photocoagulation seems feasible.

Animals↗
PubMed1994

One-year results of excimer laser photorefractive keratectomy for low to moderate myopia.

OBJECTIVE: Excimer photorefractive keratectomy is a promising method to reduce myopia. We evaluated the effectiveness, predictability, stability, and safety of photorefractive keratectomy performed by two surgeons at a single site with a 1-year follow-up. METHODS: An excimer laser (Summit Excimed UV200, Summit Technology, Waltham, Mass) was used to treat 47 eyes. Preoperative uncorrected visual acuity averaged 20/277 and ranged from 20/60 to 20/500. Spherical equivalent averaged -3.9 diopters and ranged from -1.5 to -6.1 D. RESULTS: One year postoperatively, best corrected visual acuity averaged 20/13 and ranged from 20/10 to 20/20. No patients lost any of best corrected visual acuity. The uncorrected visual acuity at 1 year averaged 20/20 and ranged from 20/10 to 20/200. Ninety-four percent of eyes had an uncorrected visual acuity of 20/40 or better; 83%, 20/25 or better; and 74%, 20/20 or better. An initial hyperopic overcorrection is followed by gradual regression to emmetropia during a 12-month period. Refractive spherical equivalent averaged 0.44 D and ranged from -3 to +2.6 D at 1 year. The proportion of eyes within 1 D of emmetropia was 80% at 1 year. The most significant shifts in refraction occurred between the first and second months, but small shifts occurred up to 12 months. Subgrouping the results according to age revealed a significantly greater effect with larger residual hyperopia in those older than 40 years. Patient satisfaction with the procedure was high. CONCLUSION: During a 1-year period, excimer photorefractive keratectomy appears to be an effective, predictable, stable, and safe method to reduce myopia. Age may play a role in the effectiveness of the procedure, with greater hyperopia resulting in those older than 40 years.

Adult↗
PubMed1994

Micrometer-scale resolution imaging of the anterior eye in vivo with optical coherence tomography.

OBJECTIVE: To demonstrate a new diagnostic technique, optical coherence tomography, for high-resolution cross-sectional imaging of structures in the anterior segment of the human eye in vivo. Optical coherence tomography is a new, noninvasive, noncontact optical imaging modality that has spatial resolution superior to that of conventional clinical ultrasonography (< 20 microns) and high sensitivity (dynamic range, > 90 dB). DESIGN: Survey of intraocular structure and dimension measurements. SETTING: Laboratory. PATIENTS: Convenience sample. MAIN OUTCOME MEASURES: Correlation with range of accepted normal intraocular structure profiles and dimensions. RESULTS: Direct in vivo measurements with micrometer-scale resolution were performed of corneal thickness and surface profile (including visualization of the corneal epithelium), anterior chamber depth and angle, and iris thickness and surface profile. Dense nuclear cataracts were successfully imaged through their full thickness in a cold cataract model in calf eyes in vitro. CONCLUSIONS: Optical coherence tomography has potential as a diagnostic tool for applications in noncontact biometry, anterior chamber angle assessment, identification and monitoring of intraocular masses and tumors, and elucidation of abnormalities of the cornea, iris, and crystalline lens.

Anterior Chamber↗
PubMed1994

Phthalocyanine photodynamic therapy: new strategy for closure of choroidal neovascularization.

Chloro-aluminum sulfonated phthalocyanine (CASPc) is a photo-chemically active dye employed in photodynamic therapy (PDT). CASPc is a potent generator of singlet oxygen when irradiated with 675 nm light and is also capable of fluorescence, allowing visualization of the dye in tissues. We devised an angiography system using CASPc fluorescence to determine its localization in experimental choroidal neovascularization in monkeys and then investigated the ability of CASPc to produce photochemical closure of neovascularization upon irradiation with 675nm laser light. Fluorescent imaging indicated that CASPc localized angiographically in areas of neovascularization for at least 24 hours. Irradiation with 675 nm laser light 5-30 minutes after CASPc injection produced complete closure of choroidal neovascularization with minimal damage to overlying retina. We conclude that CASPc localizes in neovascular choroidal vessels and that CASPc photodynamic therapy can produce closure of these choroidal vessels.

Aluminum↗
PubMed1994

Retinal and choroidal vessel closure using phthalocyanine photodynamic therapy.

Chloro-aluminum sulfonated phthalocyanine (CASPc) is a photoactive dye capable of generating photochemical reactions when excited with 675 nm light. We used CASPc to produce photochemical closure of retinal medullary ray vessels and choroidal vessels in normal rabbits. Irradiation prior to CASPc injection produced no photographic, angiographic, or histologic lesions in any eyes. Identical irradiation of medullary ray and choroidal vessels after CASPc injection produced complete vessel closure in all eyes. Histopathologic examination showed marked thrombosis of medullary ray and choroidal vessels, with minimal damage to contiguous tissues including the neurosensory retina. We conclude that CASPc can produce profound closure of normal retinal and choroidal vessels with minimal deleterious effect on surrounding tissues.

Aluminum↗
PubMed1994

Intraocular microsurgery with a picosecond Nd:YAG laser.

We investigated the use of picosecond Nd:YAG laser pulses for intraocular microsurgery. With a pulse duration of 100 picoseconds, only 70 microJ of pulse energy is required to consistently produce optical breakdown in the deep vitreous. This pulse energy is nearly two orders of magnitude less than the typical pulse energies used in conventional (nanosecond) photodisruptors. The reduced pulse energy results in a smaller zone of tissue damage, an important consideration when operating close to the retina or other sensitive ocular structures. Efficient cutting action is achieved by applying multiple pulses at a moderately high repetition rate of 50-200 Hz. An in vitro model was developed to assess axial confinement of picosecond photodisruption. In vivo vitreous membrane surgery was performed in experimental rabbit eyes to demonstrate a potential clinical application of picosecond laser-induced optical breakdown.

3T3 Cells↗
PubMed1994

Erbium-YAG and holmium-YAG laser ablation of the lens.

Er-YAG (2.9 microns, 200 microseconds pulsewidth) and Ho-YAG (2.12 microns, 250 microseconds pulsewidth) lasers were used to irradiate bovine crystalline lenses. Mass ablated increased with increasing fluence for both lasers and was greater for the Er-YAG than the Ho-YAG laser at all fluences. The mass loss vs. fluence curve was nonlinear for the Er-YAG and linear for the Ho-YAG laser. Ablation threshold was lower for the Er-YAG. Grossly, the Er-YAG laser produced less charring and expressed fewer, smaller tissue pieces than the Ho-YAG. Scanning electron microscopy indicated that the Er-YAG produced smoother walled craters. The Ho-YAG laser produced more dessicated and disrupted craters. The Er-YAG radiation, delivered by fiberoptic probes, may provide a method of performing minimally invasive cataract surgery.

Animals↗
PubMed1994

Late re-opening of macular holes after initially successful treatment with vitreous surgery.

BACKGROUND: In more than 50% of eyes with idiopathic, full-thickness macular holes, vitrectomy results in clinical closure of the hole and improvement in visual acuity. Other than cataract formation, late complications of the procedure have not been reported. METHODS: Over a 4-year period, 167 eyes underwent successful vitreous surgery for idiopathic macular holes documented by clinical closure of the hole and an improvement in visual acuity of at least two Snellen lines. The authors retrospectively studied eight of these eyes. All initially had successful surgery; however, they subsequently had spontaneous late re-opening of the macular hole with acute diminution in vision. RESULTS: Late re-opening developed in these eyes between 2 and 22 months after initial surgery. The mean time for re-opening was 12.5 months. Three of eight eyes underwent a second vitrectomy, which was successful in improving visual acuity in two eyes. Another patient manifested the growth of an epiretinal membrane that apparently sealed the re-opened macular hole and improved vision. CONCLUSION: Late re-opening can complicate initially successful macular hole surgery and may occur in at least 4.8% (8 of 167) of initially successful operations. Re-opening has been documented as late as 22 months after initial surgery. Repeat vitrectomy with gas injection may result in reclosure of the hole and improvement in vision.

Aged↗
PubMed1994

Adverse reactions due to indocyanine green.

BACKGROUND: Although adverse reactions to indocyanine green (ICG) are known to occur, the dye has been used for more than 30 years in tests of cardiac and hepatic function, with a high level of safety. Improved digital video technology has renewed interest in the use of intravenous ICG in ophthalmic imaging. This report describes the authors' experience regarding the safety of ICG for digital angiography and their recommendations for its use in the ophthalmic setting. METHODS: Digital ICG videoangiography was performed in 1226 consecutive patients, and 1923 ICG videoangiography tests were performed. A registry of adverse reactions to ICG was established. Criteria were used to define mild, moderate, and severe adverse reactions, and these data were recorded for every ICG study performed. RESULTS: There were three (0.15%) mild adverse reactions, four (0.2%) moderate reactions, and one (0.05%) severe adverse reaction. There were no deaths. CONCLUSIONS: This study documents the safety of intravenous ICG for use in ophthalmic videoangiography.

Adult↗
PubMed1994

Endoscopic laser dacryocystorhinostomy.

Endoscopic laser dacryocystorhinostomy (DCR) enables an obstructed lacrimal sac to be opened through an intranasal approach, avoiding the need for a skin incision. The holmium:yttrium aluminum garnet (holmium:YAG) laser is well-suited for this procedure because of its properties of fiberoptic delivery, effective bone cutting, and precise soft-tissue coagulation. Efficient bone ablation is particularly important for primary DCR which requires removal of relatively thick bone along the lateral nasal wall to expose the lacrimal sac. Forty-six endoscopic laser DCRs were performed on 40 patients. There were no intraoperative or postoperative complications. The surgery successfully relieved lacrimal obstruction in 85% of patients. Endoscopic instrumentation allowed for the rapid identification and correction of intranasal causes of DCR failure, including ethmoid sinus disease and middle turbinate hypertrophy. Endoscopic laser DCR appears to be a safe and effective procedure which should be considered as an alternative to external DCR for the surgical treatment of nasolacrimal duct obstruction.

Adolescent↗
PubMed1994

The photodynamic occlusion of choroidal vessels using benzoporphyrin derivative.

We used benzoporphyrin derivative-monoacid (BPD-MA), a new photosensitizing agent, in photodynamic therapy (PDT) to occlude choroidal vessels in the rabbit. Using BPD-MA, seven dutch-belted rabbit eyes were photodynamically treated to achieve acute choroidal vessel closure. Fundoscopy, fluorescein angiography (FA), and histology were performed 1 hour, 1 day, 3 days, 7 days, 14 days, 21 days, and 28 days after PDT. On FA, PDT-treated spots remained nonperfused until day 3 when gradual reperfusion from the periphery began to appear. By day 28 the area of PDT appeared completely reperfused. Histology of lesions showed acute damage to choroidal vascular endothelial cells and retinal pigment epithelial (RPE) cells. Over subsequent days, recovery of RPE cells and regeneration of large choroidal vascular endothelial cells occurred. In addition, retinal degeneration occurred gradually over the 28 days of follow-up. Since current argon laser therapy of retinal neovascularization causes immediate retinal damage, the ability to occlude choroidal vessels without inducing acute thermal damage holds promise for treating clinical pathologic conditions that feature abnormal neovascularization, such as age-related macular degeneration and diabetic retinopathy.

Animals↗