Diode-wing-pumped electro-optically Q-switched 2 μm laser with pulse energy scaling over ten millijoules

Characteristics of diode-wing-pumped highly efficient Tm:LuAG lasers running both in continuous wave (CW) and electro-optical Q-switching regimes have been investigated. Using a simple plane-plane cavity, a maximum CW output power of 8.5 W has been achieved with a corresponding slope efficiency of 44.5% by "wing pumping" at 790 nm. With a V-shaped cavity, a diode-wing-pumped MgO:LiNbO₃ crystal based electro-optically Q-switched Tm:LuAG laser at 2022.9 nm delivered a maximum pulse energy of 10.8 mJ and a minimum pulse width of 52 ns at a corresponding repetition rate of 100 Hz. To the best of our knowledge, the achieved CW output power and Q-switched pulse energy have both set records for all-solid-state Tm:LuAG lasers, which well reveals an efficient way to generate high-power and high-energy lasers at 2 μm wavelength.

Diode-pumped continuous wave tunable and graphene Q-switched Tm:LSO lasers

We have investigated the lasing characteristics of Tm:LSO crystal in three operation regimes: continuous wave (CW), wavelength tunable and passive Q-switching based on graphene. In CW regime, a maximum output power of 0.65 W at 2054.9 nm with a slope efficiency of 21% was achieved. With a quartz plate, a broad wavelength tunable range of 145 nm was obtained, corresponding to a FWHM of 100 nm. By using a graphene saturable absorber mirror, the passively Q-switched Tm:LSO laser produced pulses with duration of 7.8 μs at 2030.8 nm under a repetition rate of 7.6 kHz, corresponding to pulse energy of 14.0 μJ.

Mode-locked Tm,Ho:YAP laser around 2.1 μm

A passively mode-locked Tm,Ho:YAP laser around 2.1 μm wavelength employing a semiconductor saturable absorber mirror is demonstrated. Stable continuous wave mode-locking operation was achieved at variable center wavelengths of 2036.5 nm, 2064.5 nm, 2095.5 nm, 2103.5 nm, and 2130 nm, respectively. Pulses as short as 40.4 ps were obtained at 2064.5 nm with a spectral FWHM of 0.5 nm at output powers of 132 mW and a repetition rate around 107 MHz. A maximum output power of 238 mW was obtained at 2130 nm with a pulse duration of 66 ps.

Passively Q-switched Nd:Sc0.2Y0.8SiO5 dual-wavelength laser with the orthogonally polarized output

We have demonstrated a laser-diode pumped continuous-wave (CW) and passively Q-switched laser with a Nd:Sc(0.2)Y(0.8)SiO(5) (Nd:SYSO) crystal for the first time. In the CW operation, the laser was found to oscillate in tri-wavelength regime at 1074.8 nm, 1076.6 nm and 1078.2 nm, respectively. The maximum CW output power of 1.96 W was obtained, giving an optical-to-optical conversion efficiency of 35% and a slope efficiency of 39%. Using either Cr(4+):YAG or V(3+):YAG crystal as saturable absorber, stable passively Q-switched laser was obtained at dual-wavelength of 1074.8 nm and 1078.2 nm with orthogonal-polarization. The maximum average output power, pulse repetition rate, and shortest pulse width were 1.03 W, 50 kHz, and 24 ns, respectively. The passively Q-switched dual-wavelength laser could be potentially used as a source for generation of terahertz radiation.

Efficient continuous wave and passively mode-locked Tm-doped crystalline silicate laser

An efficient continuous wave and passively mode-locked thulium-doped oxyorthosilicate Tm:LuYSiO5 laser is demonstrated. A maximum slope efficiency of 56.3% is obtained at 2057.4 nm in continuous wave operation regime. With an InGaAs quantum well SESAM, self-starting passively mode-locked Tm:LuYSiO5 laser is realized in the 1929 nm to 2065 nm spectral region. A maximum average output power of 130.2 mW with a pulse duration of 33.1 ps and a repetition rate of about 100 MHz is generated at 1984.1 nm. Pulses as short as 24.2 ps with an average output power of 100 mW are obtained with silicon prisms where used to manage the intracavity dispersion. The shortest pulse duration of about 19.6 ps is obtained with an average output power of 64.5 mW at 1944.3 nm.

Comparative investigations on continuous wave operation of a-cut and b-cut Tm,Ho:YAlO3 lasers at room temperature

The Tm,Ho:YAlO3 laser performance for two crystal orientations pumped by a wavelength tunable Ti:Sapphire laser is presented in this paper. An experimental investigation comparing a- and b-oriented Tm,Ho:YAlO3 crystals laser performance is demonstrated and discussed. Single- and multi-wavelength operations of Tm,Ho:YAlO3 lasers have been investigated in detail. The maximum output powers of 890 mW at 2119 nm for a-oriented Tm,Ho:YAlO3 crystal and 946 mW at 2103 nm for b-oriented Tm,Ho:YAlO3 crystal have been obtained, respectively. The two crystals show very similar performance in terms of output power and conversion efficiency, only that the b-cut Tm,Ho:YAP crystal demonstrates more regimes of multi-wavelength operations.

Methods for Measuring the Crack Length in Rubbery Pure Shear and Sent Specimens

A new approach for measuring crack length, which can be used for automization of fatigue test of rubber materials, is described. The crack length in the pure shear and SENT(Single Edge Notched Tension) specimens is evaluated from the variation of the peak loads under a constant cyclic displacement. For the pure shear specimen, a simple equation to give the crack length was derived from elementary consideration of the deformation pattern. The equation was applied to two constitutive models to simulate the hyperelastic behavior. It was experimentally proven that the crack length can be measured well. For the SENT specimen, an equation to give the crack length was derived from dimensional analysis. The function was assumed to be separated as the product of the deformation and geometry functions. Experiments were performed to prove the validity of the separation and to evaluate the details of the function.

A rapid and successful treatment for airbag-related traumatic macular hole

A 28-year-old female was diagnosed as having an airbag-related traumatic macular hole in the right eye 9 days subsequent to a traffic accident. Four weeks after the trauma, the patient's visual acuity was deteriorating to 20/600. Following vitrectomy, membrane peeling, use of autologous serum and intraocular gas tamponade, the hole healed within 12 days, more rapidly than the expected interval for the treatment of a traumatic macular hole. The visual acuities at the 3-month and 1-year follow-up examinations were 20/50, much better than the conventional surgical treatment of idiopathic macular hole and comparable to previous reports of the treatment of traumatic macular hole. Vitrectomy procedure has been proved to be effective for the treatment of traumatic macular hole. Vitrectomy combined with membrane peeling, autologous serum and intraocular gas tamponade can heal the traumatic macular hole more rapidly than the conventional treatment with vitrectomy only.

Synthesis and muscarinic activity of 1,2,3,4-tetrahydropyrimidine derivatives

3-Methyl-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde O-substituted oximes 4 and 1-(3-methyl-1,2,3,4-tetrahydropyrimidin-5-yl)ethanone O-substituted oximes 9 have been prepared as bioisosteric congeners of arecoline which is a muscarinic agonist for treatment of Alzheimer's disease. Starting from pyrimidine-5-carbaldehyde 1, formation of the 3-methylpyrimidinium salt and subsequent reduction afforded 1,2,3,4-tetrahydropyrimidine derivatives which were converted into oxalate salts in the interest of purity and stability. Binding affinities of prepared compounds for the cloned human muscarinic M1 receptor (h-M1) were determined by radioligand binding assay using [3H]-N-methylscopolamine (NMS).

Triangular transchamber suture

A 64-year-old woman with a fibrous membrane at the lens plane after traumatic loss of all the iris and massive intraocular hemorrhage had posterior chamber intraocular lens (PCIOL) implantation anterior to the fibrous membrane with a triangular transchamber suture to prevent possible PCIOL-corneal touch and enhance the stability of the PCIOL. After 3 years, the PCIOL remained in a good position and visual rehabilitation was satisfactory and without complications.

A traumatic macular hole secondary to a high-energy Nd:YAG laser

A case is reported of a traumatic macular hole caused by a high-energy Nd:YAG laser. The initial ocular examination revealed an explosive, crater-shaped, full-thickness macular hole surrounded by local edema and detachment. By the 12th day after the injury, the hole had shrunk progressively and was covered by a thin fibrin-like membrane. A thick epiretinal membrane covered the injured area 1 month after the injury. Nine months after the injury, the macular hole closed spontaneously with a partially detached epiretinal membrane. This case demonstrates one of the natural healing processes of a traumatic macular hole. Although the hole finally closed, the patient did not regain his vision because of the severe damage to the photoreceptors, retinal pigment epithelium, and choroid.

Gallium-67 scanning in endogenous Klebsiella endophthalmitis with unknown primary focus

A whole-body gallium-67 (Ga-67) scan of a 61-y-old male with diabetes mellitus who suffered from endogenous Klebsiella endophthalmitis is reported. The scan revealed right orbital and lower abdominal lesions. Urinary analysis revealed pyuria. The causes of endogenous Klebsiella endophthalmitis and the usefulness of Ga-67 are discussed.

Bilateral endogenous Klebsiella pneumoniae endophthalmitis associated with meningitis-useful vision regained after treatment: case report

Endogenous endophthalmitis is a rare but devastating complication of bacteremia. Klebsiella pneumoniae is reported to be the leading organism of endogenous endophthalmitis in Taiwan, and the prognosis of endogenous Klebsiella pneumoniae endophthalmitis is extremely poor. A 46-year-old male patient was hospitalized because of fever, chills, and consciousness disturbance for 1 day. Meningitis was the impression by clinical presentation and findings of cerebrospinal fluid analysis. Parenteral ceftriaxone (4 g/day) and gentamicin (180 mg/day) were given, and his consciousness gradually cleared. On hospital day 6, he complained of blurred vision in both eyes and floaters in the left eye for 1 day. After ophthalmic examination, bilateral endogenous endophthalmitis was diagnosed. After aggressive treatment with intravitreal antibiotics and trans pars plana vitrectomy, the visual outcome of both eyes was better than those of other reported cases.

The efficacy of 0.2% brimonidine for preventing intraocular pressure rise following argon laser trabeculoplasty

Brimonidine tartrate of 0.5% was identified as the most effective and safe dose for acute intraocular pressure (IOP) lowering. The efficacy of brimonidine tartrate 0.2% in preventing IOP elevation after an argon laser trabeculoplasty (ALT) was evaluated. Eighty patients were selected for a randomized, prospective study. Each patient was assigned to one of four treatment regimens: (1) brimonidine before and after ALT(B/B), (2) brimonidine before and placebo after ALT(B/P), (3) placebo before and brimonidine after ALT(P/B), (4) placebo before and after ALT(P/P). IOP elevation of 5 mmHg or greater occurred in 3.3% (2/60) of brimonidine-treated patients and in 30% (6/20) of placebo-treated patients. There was a mean decrease of IOP from baseline during the first 3 hours after ALT in all brimonidine-treated groups (7.1 +/- 3.4, 6.2 +/- 4.4, 3.5 +/- 2.9 mmHg for the B/B, B/P, P/B groups), but no change of mean IOP in the Placebo-treated group. Only one drop of brimonidine tartrate of 0.2% installed either before or after ALT was sufficient to prevent post-ALT IOP spike and minimize the undesired systemic adverse effects that two drop installation can produce.

Evaluation of peribulbar anesthesia in encircling scleral buckle surgery and its postoperative pain course

BACKGROUND

Retrobulbar anesthesia is considered effective in ocular surgery but it can give rise to serious complications. We used peribulbar anesthesia with sub-Tenon's irrigation to perform encircling scleral buckling for retinal detachment, as it could reduce the complications caused by retrobulbar anesthesia. We also recorded the course of pain for 72 hours after surgery.

METHODS

Thirty patients who were diagnosed with rhegmatogenous retinal detachment were treated with an encircling scleral buckle. The surgery was performed with peribulbar anesthesia with occasional sub-Tenon's irrigation. We evaluated the patient's pain with a visual analogue scale after surgery at 30 minutes, 1 hour, 2 hours, 4 hours, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours.

RESULTS

In 24 cases (80%), the anesthesia was complete with the peribulbar block. Only 6 patients (20%) needed sub-Tenon's irrigation and four of them felt no pain after augmentation. Although all the surgical procedures proceeded without problem, two of the patients felt pain and were uncomfortable during the surgery. No serious complications occurred. The course of pain peaked 6 hours after surgery when 26 patients (86.7%) felt pain and 12 patients (40%) were uncomfortable (pain score > or = 5). Forty-eight hours after surgery, 9 patients (30%) still felt pain but no one felt uncomfortable.

CONCLUSION

Peribulbar anesthesia can be used safely in encircling scleral buckling for retinal detachment. The postoperative pain is maximal 6 hours after surgery and becomes mild (pain score < or = 4) after 48 hours.

Effects of hyperthermia on the cytoskeleton and focal adhesion proteins in a human thyroid carcinoma cell line

Hyperthermia is reported to act as a sensitizer to chemotherapeutic drugs in the treatment of cancer. Thyroid follicular carcinoma were used to elucidate the effects of hyperthermic treatment (41-43 degrees C) on cell morphology, cytoskeleton, and the focal adhesion complex. The critical temperature that resulted in inhibition of cell proliferation as the cell number in the same area did not increase over a 23 h time course and irreversible changes in cell morphology was 42-43 degrees C. An immunofluorescence study on heat-treated cells (43 degrees C, 1-5 h) demonstrated that depolymerization of actin filaments, intermediate filaments, and microtubules accounted for the rounding-up of cells and detachment from the substratum. Characteristic staining patterns for integrin alphav, focal adhesion kinase, and vinculin were noted in untreated cells, but the immunoreactive intensities for these proteins became weaker with time of heat treatment. Anti-phosphotyrosine staining revealed less immunoreactivity in the focal adhesions in treated cells compared with control cells. The disappearance of integrin alphav from the cell surface may result in inhibition of integrin-mediated activation of focal adhesion kinase, which results in dephosphorylation of focal adhesion components and its disassembly. These results indicate that hyperthermia induces disruption of integrin-mediated actin cytoskeleton assembly and, possibly, of other integrin-mediated signaling pathways.

Combined secondary capsulorhexis and vitreous surgery in a case of anterior capsule contraction and vitreous hemorrhage

A 59-year-old woman with diabetic vitreous hemorrhage and contracted anterior capsule opening received secondary capsulorhexis and trans pars plana vitrectomy in a single operation. The combined surgery was successful. In addition, the anterior capsule opening was enlarged by the procedure and no further vitreous hemorrhage occurred during the 6 month follow-up period in both eyes. When anterior capsule opening reduction is encountered in patients requiring vitreoretinal surgery, combining secondary capsulorhexis and vitreoretinal surgery together in a single operation maybe provide a good treatment alternative.

Extensive destruction of the eyeball by invasion of basal cell carcinoma of the eyelid

BACKGROUND

Eyeball destruction caused by invasion of basal cell carcinoma of the eyelid.

CASE

A 100-year-old woman showed extensive eyeball destruction caused by the invasion of basal cell carcinoma of the eyelid. Complete ophthalmologic examinations, including computed tomographic (CT) scans of the orbit, were performed. The patient underwent incisional biopsy and bacteriological examination of the exudate from the lesion.

OBSERVATIONS

Orbital CT scan showed a mass in the extraconal space of the right orbit, with extension to the adjacent sinus cavity without brain involvement. The remnant of the eyeball was posteriorly displaced. Pseudomonas aeruginosa was identified by culture examination of the exudate. Histological study of the biopsy specimen showed basal cell carcinoma of the noduloulcerative type.

CONCLUSIONS

Basal cell carcinoma of the eyelid had caused severe periorbital and eyeball destruction.

Rapidly resorptive exudative retinal detachment in a patient with renogenic hypertension: case report

We present an 18-year-old woman who developed rapidly resorptive exudative retinal detachment (ERD) due to chronic renal failure and renogenic hypertension. In July 1998, the patient came to our clinic because of a 2-month-history of progressively deteriorating visual acuity. Initially examination of the fundi revealed typical hypertensive retinopathy. Two weeks later, the patient was admitted due to hypertension and consulted our ophthalmic department again. In addition to hypertensive retinopathy, the fundi showed high bullous ERD, involving the temporal retinas in both eyes. Intensive medical therapy was begun, including blood pressure control and maintenance of body fluid and electrolyte balance, resulting in almost complete regression of retinal detachment within two days. The visual acuity improved during the following 2 weeks. The clinical features and treatment response in this rare case indicate that multiple factors, including fluids overload, hypertension, and possibly renal failure, contributed to the development of ERD. Blood pressure control and the balance of fluids are important in patients with renal failure, and may help to prevent the occurrence of ERD.

The role of adjunctive mitomycin C in secondary glaucoma triple procedure as compared to primary glaucoma triple procedure

OBJECTIVE

This study aimed to investigate whether previously failed glaucoma filtration surgery is a risk factor for filtration failure of subsequent trabeculectomy combined with cataract surgery and to determine the role of adjunctive mitomycin C (MMC) in the secondary glaucoma triple procedure (SGTP) as compared to primary glaucoma triple procedure (PGTP).

DESIGN

A prospective, controlled study that was randomized with respect to assignment to adjunctive MMC and a case-control design with respect to comparisons between SGTP and PGTP was studied.

PARTICIPANTS

The SGTP group consisted of 49 eyes of 49 consecutive patients with primary open-angle glaucoma with a history of glaucoma filtration surgery requiring glaucoma medical therapy and in need of cataract surgery, randomized to adjunctive MMC (SGTP MMC subgroup of 21 eyes) and no adjunctive MMC (SGTP control subgroup of 28 eyes). The PGTP group consisted of 49 PGTP cases closely matched to the SGTP cases with respect to age, race, gender, MMC use, C:D ratio, and systemic diseases.

INTERVENTION

Trabeculectomy combined with phacoemulsification and a small incision (5 x 6 mm), all polymethylmethacrylate posterior chamber intraocular lens implantation with or without adjunctive MMC (0.5 mg/ml for 1 minute), was performed.

MAIN OUTCOME MEASURES

Surgery failure was defined as the need of an additional intraocular procedure or the need of more than one medication to achieve intraocular pressure control to the target level. Intragroup and intergroup comparisons were made with respect to filtration outcome among the SGTP and PGTP patients.

RESULTS

Without adjunctive MMC, filtration success was significantly less in SGTP than in PGTP (P = 0.03). Adjunctive MMC significantly increased the success rate of SGTP (P = 0.02) but not that of PGTP (P = 0.89) over the average follow-up period of 2 years.

CONCLUSIONS

Previously failed glaucoma filtration surgery is a significant risk factor for the filtration failure of combined surgery. Intraoperative use of adjunctive MMC significantly improves the filtration success rate of SGTP.

Primary glaucoma triple procedure in patients with primary open-angle glaucoma: the effect of mitomycin C in patients with and without prognostic factors for filtration failure

PURPOSE

To investigate the effect of adjunctive mitomycin C on primary glaucoma triple procedure in patients with primary open-angle glaucoma with and without one or more of the prognostic factors for filtration failure of primary glaucoma triple procedure. Those factors include being of African-American race, having a preoperative intraocular pressure of 20 mm Hg or more on maximum tolerated medications, and being on two or more medications preoperatively.

METHODS

Study patients consisted of 197 consecutive patients with primary open-angle glaucoma who were randomly assigned to receive either no adjunctive mitomycin C (101 eyes of 101 patients) or to receive adjunctive subconjunctival mitomycin C (96 eyes of 96 patients) during the primary glaucoma triple procedure. Kaplan-Meier survival analysis comparisons were made between respective subgroups with and without prognostic indicators for filtration failures using a relatively stringent set of criteria for filtration success of primary glaucoma triple procedure.

RESULTS

There was no statistically significant (P = .117) difference in filtration success of primary glaucoma triple procedure between the control and mitomycin C groups. Adjunctive mitomycin C significantly (P < .05) improved the filtration outcome of the primary glaucoma triple procedure in the subgroups with each of the three prognostic factors for filtration failure of primary glaucoma triple procedure. On the other hand, in the subgroups without the prognostic factors, adjunctive mitomycin C did not significantly (P > .05) change the filtration outcome of the primary glaucoma triple procedure.

CONCLUSION

These findings establish the basis for selective use of mitomycin C in patients with primary open-angle glaucoma undergoing primary glaucoma triple procedure.

A new technique for repositioning a posteriorly dislocated intraocular lens

Pars plana vitrectomy was performed to treat a complete posterior dislocation of an intraocular lens in seven patients. The method that the authors have developed appears to be safer and simpler than those previously described. The haptics are externalized for a secure tie at the proper site, and are then reinternalized back through the pars plana sclerotomies. Only two small needle perforations are made for the scleral fixation of the intraocular lens in the ciliary sulcus. Perfluorocarbon liquid is used to prevent intraoperative retinal damage.

Mitomycin-C supplemented trabeculectomy, phacoemulsification, and foldable lens implantation

PURPOSE

To evaluate the outcome of combined mitomycin-C filtering surgery, phacoemulsification, and foldable intraocular lens (IOL) implantation.

SETTING

Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.

METHODS

This retrospective study evaluated 182 eyes of 174 patients who had combined mitomycin-C trabeculectomy, phacoemulsification, and insertion of a foldable IOL through a 3.5 mm incision. Success of the combined procedure was defined as intraocular pressure (IOP) below 21 mm Hg, with or without medications, and no serious complication. Success rates were calculated using the Kaplan-Meier actuarial method.

RESULTS

Mean follow-up was 16.7 months +/- 5.4 (SD). The probability of success at 6, 12, 18, and 24 months was 98.3, 95.6, 90.6, and 88.0%, respectively. When compared with preoperatively, visual acuity improved one or more lines in 148 eyes (81.3%) and worsened one or more lines in 15 (8.2%); 111 eyes (61.0%) achieved visual acuity of 20/40 or better. The most frequent complication was posterior capsule opacification requiring capsulotomy, which occurred in 22 cases (12.0%).

CONCLUSION

The 1 year and 2 year IOP control rate of combined mitomycin-C filtering procedures and phacoemulsification in glaucoma patients was high.

Primary glaucoma triple procedure with or without adjunctive mitomycin. Prognostic factors for filtration failure

PURPOSE

The prerequisite for selective use of adjunctive mitomycin C (MMC) in primary glaucoma triple procedure (PGTP) is a better understanding of the prognostic factors. Therefore, the authors carried out the current study on the outcome of PGTP with and without adjunctive MMC to determine the prognostic factors for filtration failure of PGTP.

METHODS

The study patients consisted of 174 consecutive primary open-angle glaucoma (POAG) patients undergoing PGTP. They were assigned randomly to either no adjunctive MMC (93 eyes of 93 patients) or adjunctive subconjunctival MMC (81 eyes of 81 patients) during the PGTP. After surgery, the patients were examined at regular intervals for visual acuity, intraocular pressure (IOP) control, medical therapy requirements, and complications. Filtration failure was determined according to two different criteria: (1) a less stringent set of criteria (criterion I) and (2) a more stringent set of criteria (criterion II).

RESULTS

There were no statistically significant differences between the groups with and without adjunctive MMC with respect to postoperative IOP, number of medications, and visual acuity outcome during mean follow-up (+/- standard deviation) of 25.1 +/- 5.5 months (P > 0.05 for each). However, there were prognostic factors for filtration failure in the control group but not in the MMC group. Black race, diabetes mellitus, preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than two were found to be significant prognostic factors for filtration failure by criterion I. Black race, preoperative IOP greater than or equal to 20 mmHg and number of preoperative medications greater than 1 were significant prognostic factors for filtration failure by criterion II.

CONCLUSION

There was no statistically significant difference in the overall outcome of PGTP between control and MMC groups of nonselected patients with primary open-angle glaucoma. Black race, diabetes mellitus (by criterion I only), preoperative IOP greater than or equal to 20 mmHg, and number of preoperative medications greater than 2 (by criterion I) or greater than 1 (by criterion II) were found to be significant independent prognostic factors for filtration failure of PGTP without adjunctive MMC but no with adjunctive MMC. The use of adjunctive subconjunctival MMC in PGTP may have to be selective, primarily in those patients with primary open-angle glaucoma with one or more of the prognostic factors for filtration failure.