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At least 109 records · Page 6Linked to original sources
PubMed1996

Multicenter clinical experience using an erbium:YAG laser for vitreoretinal surgery.

PURPOSE: To evaluate the advantages, disadvantages, safety, complications, and surgical applicability of an erbium:YAG laser system for maneuvers in vitreoretinal surgery. METHODS: A prospective, consecutive trial of 68 eyes in 66 patients undergoing vitreoretinal surgery in which an erbium:YAG laser with graduated output from 0.2 to 5.0 mJ per pulse, repetition rate of 2 to 30 Hz, and equipped with a flexible fiber optic and interchangeable 20-gauge intraocular fiber optic endoprobes was used to perform specific maneuvers, including transection, incision, and ablation of membranes, retinotomy, vessel coagulation, iridectomy, and lens tissue ablation. The patients were treated in five centers in contemporary vitreoretinal surgical settings for surgical indications, including proliferative diabetic retinopathy, proliferative vitreoretinopathy, epiretinal membrane, and retinopathy of prematurity. RESULTS: One hundred seventy-four maneuvers were performed with an overall surgical efficacy rating of excellent or good in 84% of maneuvers, ranging from a high of 100% for subretinal membrane transection to a low of 25% for coagulation of blood vessels. Complications included retinal break or photocoagulative injury in 5% of epiretinal membrane incisions, minor bleeding from transected retinal vessels during 29% of retinotomies, and intraocular lens damage during two posterior capsulotomies. The most significant limitation was the cautious pace used during maneuvers near the retinal surface. CONCLUSION: The erbium:YAG laser is capable of versatile new approaches offering precise tissue cutting and ablation in vitreoretinal surgical maneuvers with a high degree of safety. The main limitation encountered was the slow speed of certain critical maneuvers near the retina.

Adult↗
PubMed2006

Novel stoichiometrically erbium-ytterbium cocrystalline complex exhibiting enhanced near-infrared luminescence.

Three beta-diketonate complexes of erbium and ytterbium, Er(HFA)3(TPPO)3, Yb(HFA)3(TPPO)3, and Er(1/2)Yb(1/)(2)(HFA)3(TPPO)2 (HFA = hexafluoroacetylacetonate, TPPO = triphenylphosphine oxide) are synthesized and structurally characterized, and their luminescent properties are examined in detail. Compared with monometallic complexes Er(HFA)3(TPPO)3 and Er(HFA)3(TPPO)3, the stoichiometrically Er-Yb cocrystalline complex Er(1/2)Yb(1/2)(HFA)3(TPPO)2 exhibits special indirect near-infrared (NIR) luminescence with the acceptor and sensitizer (donor) coexisting in a single crystal. Of interest is that the NIR luminescence of the erbium ion in Er(1/2)Yb(1/2)(HFA)3(TPPO)2 is significantly enhanced because of the coexistence of the ytterbium ion through the energy-transfer between the ytterbium and erbium ions. The estimated donor-acceptor energy-transfer critical radii R(C,DA), obtained from the Förster model, are in good agreement with those determined from the single X-ray crystal structure, confirming the dipole-dipole character for such a Yb-Er energy-transfer process.

Journal Article↗
PubMed2002

Crystallographic characterization of the structure of the endohedral fullerene [Er2@C82 isomer I] with C(s) cage symmetry and multiple sites for erbium along a band of ten contiguous hexagons.

The structure of one of the three previously separated isomers of {Er2@C82} has been determined through a single-crystal X-ray structure determination of the noncovalent adduct, {Er2@C82 Isomer I}.{CoII(OEP)}.1.4(C6H6).0.3(CHCl3). The C82 cage is identified specificlly as the Cs(82:6) isomer (one of nine possible isolated pentagon isomers) from the crystallographic data. The carbon atoms of the C82 cage were individually identified and refined with only a constraint that required the two halves of the cage to possess similar bond lengths. Although the carbon cage is well ordered at 113 K, the erbium atoms are disordered. The electron density within the cage of {Er2@C82 Isomer I} has been modeled with two major sites with occupancies of 0.35 and 21 other individual erbium sites with occupancies ranging from 0.138 to 0.011. These erbium sites all reside near the walls of the fullerence and cluster near a band of ten contiguous hexagons that encircles the carbon cage. Since two other isomers of C82 (C3v(82:8) and C2v(82:9)) have a similar band of ten contiguous hexagons, it is tempting to speculate that the other two known isomers of {Er2@C82} have these cage structures.

Journal Article↗
PubMed2000

Dermatologic surgery: pulsed erbium:YAG laser-assisted autologous epidermal punch grafting in vitiligo.

BACKGROUND: A pilot study was conducted to evaluate the efficacy and safety of pulsed erbium:YAG laser ablation of autologous minipunch grafted sites for the treatment of refractory or stable vitiligo. METHODS: Thirteen patients, seven men and six women, aged between 19 and 58 years, with Fitzpatrick skin types ranging from type IV to VI, were grafted. The pulsed erbium: YAG laser was used to create recipient graft sites. RESULTS: Repigmentation was observed in 12 out of 13 patients. Failure of grafts to repigment ranged from 3% to 100%. No untoward side-effects of surgery were noted. CONCLUSIONS: Using an erbium:YAG laser to create graft recipient sites permits the survival of punch harvested grafts and the spread of pigmentation to the surrounding skin.

Adult↗
PubMed1999

Erbium:YAG laser resurfacing for refractory melasma.

BACKGROUND: Melasma is a facial dyspigmentation which is a common complaint in patients with darker skin tones. Many current therapies used for this condition are ineffective and can cause significant adverse effects. OBJECTIVE: The purpose of this study was to evaluate the role of erbium:YAG laser resurfacing in the management of refractory melasma. METHODS: Ten female patients with melasma unresponsive to previous therapy of bleaching creams and chemical peels were included in this study. Full face skin resurfacing using an erbium: YAG laser (2.94 microm) was performed using 5.1-7.6 J/cm2 energy. Clinical evaluations using the Melasma Area and Severity Index (MASI) and melanin reflectance spectrometry measurements were taken preoperatively and at 0.5, 1, 1.5, 3, and 6 weeks and 3, 5, and 6 months postoperatively. Adverse effects after laser resurfacing such as prolonged erythema, infection, and hyperpigmentation were recorded. RESULTS: There was marked improvement of the melasma immediately after laser surgery using the parameters outlined; however, between 3 and 6 weeks postoperatively, all patients exhibited post-inflammatory hyperpigmentation. Decreased MASI and melanin reflectance spectrometry measurement scores were noted after biweekly glycolic acid peels and at the end of 6 months, significant clinical improvement in the melasma was seen compared to the preoperative evaluation. CONCLUSION: Erbium:YAG laser resurfacing effectively improves melasma; however, the almost universal appearance of transient post-inflammatory hyperpigmentation necessitates prompt and persistent intervention. The use of this laser therapy is recommended only for refractory melasma.

Adult↗
PubMed2002

Nonablative laser skin resurfacing using a 1540 nm erbium glass laser: a clinical and histologic analysis.

BACKGROUND: A variety of laser systems have recently become available that allow for selective dermal remodeling without disruption of the epidermal surface. Modest clinical improvement in mild to moderate photoinduced facial rhytides with minimal morbidity is typical of these nonablative lasers, providing a significant advantage over traditional ablative laser systems. OBJECTIVE: To determine the clinical and histologic effects of a novel 1540 nm erbium glass laser on facial rhytides. METHODS: Patients with mild to moderate periorbital and perioral rhytides received a series of three monthly treatments with a 1540-nm erbium-doped phosphate glass laser by a single operator. Photographic and clinical evaluations were independently conducted by the patient and a masked medical observer at each treatment visit and at 1, 3, and 6 months following the final treatment session. Skin biopsies were obtained for histologic analysis by a board-certified dermatopathologist at baseline, immediately following laser irradiation, and at one and six months post-treatment. RESULTS: Slow, progressive clinical improvement of rhytides was noted in all patients after each treatment and continued throughout the extended follow-up period. Side effects of treatment were limited to transient erythema and edema immediately following laser irradiation. No serious adverse effects were noted. Histologic skin changes were not apparent until several months following treatment, when an increase in dermal collagen was noted. CONCLUSIONS: The nonablative 1540 nm erbium glass laser system with contact cooling produces gradual clinical and histologic improvement in mild to moderate facial rhytides with minimal risk of serious adverse sequelae.

Adult↗
PubMed2003

[Results after erbium:YAG-laser stapedotomy].

BACKGROUND: The analysis of postoperative results after Erbium : YAG-Laser stapedotomy in patients with otosclerosis. METHODS: For all operations the microscope-integrated Erbium : YAG-Laser Twin ER (Zeiss, Oberkochen) was used by different surgeons. Data of 53 patients who were operated on between October 1993 and May 1999 were analysed. The mean follow-up time was 17 months. Postoperative bone-conduction and air-conduction thresholds and the presence of postoperative tinnitus and vertigo were analysed. The data were analysed according to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (1994). RESULTS: In 49 patients unchanged preoperative minus postoperative pure tone bone conduction averages at 1, 2, and 4 kHz were observed. In 4 patients a slight deterioration between 10 and 20 dB was seen. In 2 patients a new postoperative tinnitus was observed. No patient suffered from vertigo at the time of evaluation. In 22 patients the postoperative air-bone gap was between 0 and 10 dB, in 25 patients between 11 and 20 dB, and in 6 patients between 21 and 30 dB. No patient had a postoperative air-bone gap of more than 30 dB. CONCLUSIONS: The Erbium : YAG-Laser stapedotomy is a safe technique. Good postoperative hearing results may be achieved in patients with otosclerosis.

Adolescent↗
PubMed2003

Erbium:YAG laser skin resurfacing: a Pakistani experience.

BACKGROUND AND OBJECTIVES: To evaluate the use of the erbium:YAG laser for resurfacing in type IV skin patients in Pakistan. STUDY DESIGN/MATERIALS AND METHODS: Ten patients with skin type IV underwent laser skin resurfacing with an erbium:YAG laser to treat wrinkles, acne/chickenpox scars and hyperpigmentation. An evaluation was done by the treating physician and a photographic evaluation and grading was done by a blinded observer. RESULTS: The treating physician's records show no erythema, pigmentary alteration, infection or scarring at the 3-month follow-up. The blinded observer's evaluation of the 3-month photographs showed moderate to excellent improvement in 80% of patients in their respective underlying condition. CONCLUSION: The erbium:YAG laser is safe and effective in treating wrinkles, acne/chickenpox scars and hyperpigmentation in skin type IV patients.

Acne Vulgaris↗
PubMed1999

Skin contraction with pulsed CO2 and erbium:YAG laser.

The purpose of this study was to assess the physical response of skin to laser resurfacing in a real-time, quantitative fashion. The study was designed to assess skin contraction from two opposite standpoints. First, change in tension was measured during laser application while samples were held at constant length. Second, change in length of a sample under no tension was measured during laser treatment. These two disparate analyses represent the two possible extremes of the clinical situation in which skin exists under some tension with some laxity to allow for decrease in length. A custom apparatus with digital interface for skin tension measurements was used to produce single sample tracings of change in skin tension with laser treatment. Length change was measured for individual samples by continuous sonomicrometer readings. Individual sample data were then plotted in a time versus tension/length graph. Skin contracts immediately to a peak level and then relaxes to a sustained plateau level for both CO2 and erbium:YAG lasers. Increased contraction was noted when the beam penetrated into the dermis. Greater peak and plateau contraction is observed after the beam has penetrated into the dermis. Skin contraction varies directly with energy for CO2 and erbium:YAG laser. Findings were similar when skin tension was measured with the sample held at constant length and when length change was measured with the sample under no tension. Char left on the skin after a pass with CO2 laser substantially decreases skin contraction. High-density settings with CO2 laser yield pulse stacking, which effectively irradiates the same portion of tissue with char on it. Skin contraction varies inversely with computer pattern density settings for CO2 laser due to this pulse stacking effect. Density has little effect on skin contraction for the erbium:YAG laser because little char is generated. Histologic analysis identified a zone of coagulated dermis that correlates linearly with skin contraction.

Animals↗
PubMed2003

Increasing the efficiency of erbium-based sources using silicon quantum dots.

Silicon nanoclusters exhibit novel and interesting optical and electrical properties that are not observed in bulk silicon. Moreover, it has been discovered that there exists a strong coupling between nanoclusters and rare-earth ions that results in efficient energy exchange between the two species. This paper presents a review of recent work at University College London in this area, in which we have studied the optical properties of silicon nanoclusters in silica with rare-earth co-dopants and have developed a model for the excitation of erbium ions in erbium-doped silicon nanocrystals via coupling from optically generated excitons confined within the silicon nanoclusters. The model provides a phenomenological description of the exchange mechanism and allows us to evaluate an effective absorption cross-section for erbium that is up to four orders of magnitude higher than the corresponding value in stoichiometric silica. This paper also discusses the origin of the 1.6 eV emission band associated with the silicon nanoclusters and determines absorption cross-sections and excitonic lifetimes for nanoclusters in silica.

Journal Article↗
PubMed2006

Transmission electron microscopy characterization of the erbium silicide formation process using a Pt/Er stack on a silicon-on-insulator substrate.

Very thin erbium silicide layers have been used as source and drain contacts to n-type Si in low Schottky barrier MOSFETs on silicon-on-insulator substrates. Erbium silicide is formed by a solid-state reaction between the metal and silicon during annealing. The influence of annealing temperature (450 degrees C, 525 degrees C and 600 degrees C) on the formation of an erbium silicide layer in the Pt/Er/Si/SiO(2)/Si structure was analysed by means of cross-sectional transmission electron microscopy. The Si grains/interlayer formed at the interface and the presence of Si grains within the Er-related layer constitute proof that Si reacts with Er in the presence of a Pt top layer in the temperature range 450-600 degrees C. The process of silicide formation in the Pt/Er/Si structure differs from that in the Er/Si structure. At 600 degrees C, the Pt top layer vanishes and a (Pt-Er)Si(x) system is formed.

Journal Article↗
PubMed1998

Erbium:YAG laser resurfacing in Asians.

BACKGROUND: Although laser resurfacing has become increasingly popular in the treatment of Caucasian skin, concerns about healing and postinflammatory pigmentary changes have limited its use in Asian skin. OBJECTIVE: The purpose of this study was to determine the efficacy and safety of the Erbium(ER):YAG laser used in the treatment of Asian skin. METHODS: Fifty Asian individuals with Rhytids, scars, pigmentary alteration, and a variety of cutaneous growth were treated with the Erbium:YAG laser. Patients were evaluated for clinical efficacy, wound healing, post-operative erythema, and post-inflammatory pigmentary changes. RESULTS: Significant improvement was noted in all individuals. Shorter periods for re-epithelization and erythema duration were noted when compared to previously reported results following carbon dioxide laser resurfacing. CONCLUSION: The Erbium:YAG laser is safe and effective in the treatment of Asian skin.

Adolescent↗
PubMed2006

Efficacy and safety of the short-pulse erbium:YAG laser in the treatment of acquired melanocytic nevi.

BACKGROUND: Various laser systems have been used in the treatment of acquired melanocytic nevi. However, CO2 lasers may cause scarring, and some nevi cannot be removed with pigment-specific lasers completely. To date, no study has evaluated the efficacy and safety of an erbium:yttrium-aluminum-garnet (YAG) laser, with its small penetration depth and fewer adverse effects, in the treatment of acquired melanocytic nevi. OBJECTIVE: To investigate the efficacy and safety of the short-pulse erbium:YAG laser in the treatment of acquired melanocytic nevi. METHODS: The study included 28 nevi in 14 patients. The lesions were pigmented, flat, or just palpable nevi. Nevi were irradiated with single-pulse laser energy of 1,000 mJ and a pulse duration of 300 microseconds. Fluences between 5.2 and 14.4 J/cm2 were used. Four months following laser treatment, the entire lesion was excised. Each specimen was histopathologically and immunohistochemically examined for the presence of nevus cells. RESULTS: Clinically, all of the nevi and, histopathologically, 27 of 28 nevi (96%) were completely removed without scarring. Post-inflammatory hyperpigmentation was seen in two patients and hypopigmentation in three patients. CONCLUSIONS: Short-pulse erbium:YAG laser treatment is an effective and safe method for removing acquired melanocytic nevi.

Adult↗
PubMed2007

Fractional photothermolysis: treatment of facial and nonfacial cutaneous photodamage with a 1,550-nm erbium-doped fiber laser.

PURPOSE: To evaluate the safety and effectiveness of a novel nonablative 1,550 nm erbium-doped fiber laser in the treatment of facial and non-facial photodamaged skin. METHODS: 50 patients with mild to moderate cutaneous photodamage, rhytides, and dyspigmentation received 3 successive treatments at 3-4 week intervals with a 1,550 nm erbium-doped fiber laser (Fraxel, Reliant Technologies Inc., San Diego, CA). Clinical improvement of treatment areas was independently determined by two masked assessors' evaluations of comparative photographs at baseline and 3, 6, and 9 months post-treatment using a quartile grading scale. Patient satisfaction surveys were also obtained at each follow-up visit. RESULTS: Mean clinical improvement at 3 months for the face was 2.23 and 1.85 for non-facial skin (p<0.001). Mean improvement at 6 months was 2.10 for the face and 1.81 for non-facial skin (p<0.001). Mean improvement at 9 months was 1.96 for the face and 1.70 for non-facial skin (p<0.001). At least 51% to 75% improvement in photodamage at the 9-month follow-up was achieved in 73 and 55% of facial and non-facial treated skin, respectively. Side effects were limited to transient erythema and edema in the majority of patients. No prolonged pigmentary changes or scarring were observed. Patient satisfaction surveys mirrored the observed clinical effects. CONCLUSION: The nonablative 1,550 nm erbium-doped fiber laser is an effective treatment for facial and non-facial photodamage, rhytides, and dyspigmentation with a favorable recovery and side effect profile.

Adult↗
PubMed2004

Conception and characterization of a dual-concentric-core erbium-doped dispersion-compensating fiber.

We present an erbium-doped dispersion-compensating fiber made up of two asymmetric concentric cores, inner and outer matched claddings, and erbium located in the central core only. We demonstrate a high negative chromatic dispersion value [-700 ps/(nm km) at 1568 nm], significant modification of the gain spectrum compared with that of a classic erbium-doped fiber amplifier, and 30-dB peak small-signal gain at 1535 and 1553 nm.

Journal Article↗
PubMed2005

Continuous-wave supercontinuum laser based on an erbium-doped fiber ring cavity incorporating a highly nonlinear optical fiber.

We experimentally demonstrate a novel erbium-doped fiber based continuous-wave (cw) supercontinuum laser. The laser has a simple ring-cavity structure incorporating an erbium-doped fiber and a highly nonlinear dispersion-shifted fiber (HNL-DSF). Differently from previously demonstrated cw supercontinuum sources based on single propagation of a strong Raman pump laser beam through a highly nonlinear fiber, erbium gain inside the cavity generates a seed light oscillation, and the oscillated light subsequently evolves into a supercontinuum by nonlinear effects such as modulation instability and stimulated Raman scattering in the HNL-DSF. High quality of the depolarized supercontinuum laser output with a spectral bandwidth larger than 250 nm is readily achieved.

Journal Article↗
PubMed2006

Wavelength-spacing tunable multiwavelength erbium-doped fiber laser based on four-wave mixing of dispersion-shifted fiber.

We experimentally demonstrate a wavelength-spacing tunable multiwavelength erbium-doped fiber laser based on degenerate four-wave mixing in a dispersion-shifted fiber incorporating multiple-fiber Bragg gratings. We have achieved stable operation of the multiwavelength erbium-doped fiber laser, which has 0.8 nm spacing ten-channel lasing wavelengths and a high extinction ratio of more than approximately 45 dB, at room temperature. The output power of the multiwavelength erbium-doped fiber laser is stable, so the peak fluctuation is less than approximately 0.2 dB. By changing the properties such as loss and polarization state of multiple fiber Bragg grating cavities, we can exercise flexible control of the wavelength spacing of the multiwavelength output. We can also obtain switchable multiwavelength lasing operation by elimination of the effects of alternate single-fiber Bragg gratings.

Journal Article↗
PubMedDate not supplied

Use of Erbium:YAG laser in the treatment of palpebral xanthelasmas.

OBJECTIVE: In light of the research and the use of lasers in the therapy of xanthelasmas, the authors report their experience in the treatment of this pathology with Erbium:YAG laser. MATERIALS AND METHODS: In 30 patients, all female, 70 xanthelasmas were treated with Erbium:YAG laser, 65 (93%) of which were on the upper eyelid and 5 (7%) on the lower eyelid, varying from 1 x 1.5 mm to 11 X 20 mm in size. Spots with a diameter of 1.6 mm, energy of 300 mJ, frequency of 1-5 Hz and in a number varying were used in relation to the extent of the pathology. RESULTS: In all cases, the appearance and functional results were good, without leaving scars and/or dyschromia. CONCLUSIONS: Erbium:YAG laser, in the treatment of xanthelasmas, is a parasurgical method that is simple to perform and because of the successful aesthetic and functional results, is a valid alternative to the more traditional treatment methods.

Adult↗