Prognostic Factors for Recurrent Rhegmatogenous Retinal Detachment after Silicone Oil Removal.

PURPOSE: To investigate the prognostic factors for recurrent rhegmatogenous retinal detachment following silicone oil removal. METHODS: This retrospective review included 147 consecutive patients with rhegmatogenous retinal detachment treated with silicone oil tamponade at a high-volume referral-based tertiary hospital between January 2012 and May 2022. All patients underwent follow-up for a minimum of 6 months after subsequent silicone oil removal. The primary outcome measure was the rate of recurrent retinal detachment following silicone oil removal, and the secondary outcome was best-corrected visual acuity after silicone oil removal. RESULTS: The mean silicone oil tamponade duration was 4.7 ± 5.01 months (range, 1-38 months; median, 3 months), and the recurrent retinal detachment rate after silicone oil removal was 15.6%. Logistic regression analysis revealed that argon endolaser photocoagulation during silicone oil removal (odds ratio [OR], 0.309; 95% confidence interval [CI], 0.106-0.898; p = 0.031) was associated with a lower rate of anatomical success after silicone oil removal. Demographics, preoperative ocular characteristics, proliferative vitreoretinopathy, previous scleral encircling or buckling, previous retinectomy, concomitant phacoemulsification, duration of silicone oil tamponade, and gas tamponade after silicone oil removal were not significantly associated with recurrent retinal redetachment after silicone oil removal. Duration of silicone oil tamponade (OR, 1.226; 95% CI, 1.073-1.402; p = 0.003) and recurrent retinal detachment after silicone oil removal (OR, 3.400; 95% CI, 1.311-8.817; p = 0.012) were associated with poor visual outcomes after silicone oil removal. CONCLUSIONS: Among all factors examined in this study, including the duration of silicone oil tamponade, laser retinopexy was the only significant prognostic factor for recurrent retinal detachment after silicone oil removal. A longer duration of silicone oil tamponade was associated with worse visual outcomes and a lower rate of visual improvement after silicone oil removal.

In vivo imaging of choroidal angiogenesis using fluorescence-labeled cationic liposomes.

PURPOSE: Precise monitoring of active angiogenesis in neovascular eye diseases such as age-related macular degeneration (AMD) enables sensitive use of antiangiogenic drugs and reduces adverse side effects. So far, no in vivo imaging methods are available to specifically label active angiogenesis. Here, we report such a technique using fluorophore-labeled cationic liposomes (CL) detected with a standard clinical in vivo scanning laser ophthalmoscope (SLO). METHODS: C57Bl/6 mice underwent laser coagulations at day 0 (d0) to induce choroidal neovascularization (CNV). Liposomes labeled with Oregon green, rhodamine (Rh), or indocyanine green (ICG) were injected into the tail vein at various time points after laser coagulation, and their fluorescence was observed in vivo 60 min later using an SLO, or afterwards in choroidal flatmounts or cryosections. RESULTS: SLO detected accumulated fluorescence only in active CNV lesions with insignificant background noise. The best signal was obtained with CL-ICG. Choroidal flatmounts and cryosections of the eye confirmed the location of retained CL in CNV lesions. Neutral liposomes, in contrast, showed no accumulation. CONCLUSIONS: These results establish fluorophore-labeled CL as high affinity markers to selectively stain active CNV. This novel, non-invasive SLO imaging technique could improve risk assessment and indication for current intraocular antiangiogenic drugs in neovascular eye diseases, as well as monitor therapeutic outcomes. Labeling of angiogenic vessels using CL can be of interest not only for functional imaging in ophthalmology but also for other conditions where localization of active angiogenesis is desirable.

Inhibitory efficacy of intravitreal dexamethasone acetate-loaded PLGA nanoparticles on choroidal neovascularization in a laser-induced rat model.

PURPOSE: The aims of this study were to investigate the inhibitory efficacy of intravitreal dexamethasone acetate (DA)-loaded by (D, L-lactide-co-glycolide) (PLGA) nanoparticles on choroidal neovascularization (CNV) in a laser-induced rat model and to evaluate its mode of drug release. METHODS: DA loaded with PLGA nanoparticles containing 50% DA was prepared using an emulsification/solvent evaporation method. CNV was unilaterally induced by laser photocoagulation in rats. Different dosages of sterilized DA-loaded PLGA nanoparticles suspensions by intravitreal injection were evaluated (i.e., 50, 100, 200, and 400 mug) and the blank PLGA vehicle was the control. The concentration of DA in vitreous was measured by reverse-phase high-performance liquid chromatography (RP-HPLC). Flash electroretinography and transmission electron microscopy were performed to assess retinal toxicity. Fluorescein fundus angiography was performed to evaluate the incidence of CNV on days 14 and 56. The animals were sacrificed on day 56, then eyecups were processed for histologic analysis. RESULTS: The in vitro release of DA from nanoparticles showed that 50% of the drug was released over 2 weeks and controlled release in a linear pattern for 40 days. The pharmacokinetics of DA-loaded PLGA nanoparticles in the eyes with CNV demonstrated a triphasic pattern. The DA concentrations in vitreous remained within the effective range, which is capable of inhibiting inflammatory responses for more than 56 days. On day 14 after photocoagulation, the incidence of CNV was 47.4% as for 50 microg, 28.2% for 100 microg, 15.8% for 200 microg and 7.9% for the 400 microg DA-loaded PLGA nanoparticles group, respectively, and 65.8% for the control. On day 56, The inhibition of DA-loaded PLGA nanoparticles on CNV showed a dose-dependent effect. No sign of retinal toxicity was detected. CONCLUSIONS: These results suggest that DA-loaded PLGA nanoparticles can dose-dependently inhibit the development of experimental CNV. The controlled intraocular delivery system of DA-loaded PLGA nanoparticles may be a potentiality for CNV treatment.

Chorioretinal temperature monitoring during transpupillary thermotherapy for choroidal neovascularisation.

AIMS: To investigate the difference in temperature rise between normal choroid and choroidal revascularisation (CNV) during transpupillary thermotherapy (TTT) and the relation between laser spot size and power in the rat fundus. METHODS: A modified slit lamp, which was installed with two laser wavelengths (490 nm for illumination and fluorescein excitation and 810 nm for hyperthermia), was developed for TTT and temperature monitoring. Temperature rise during TTT was monitored by observing fluorescence released from thermosensitive liposomes encapsulating carboxyfluorescein. Two types of liposomes were prepared; their phase transition temperatures were 40 degrees C and 46 degrees C, respectively. Laser power settings required to observe fluorescence released from 46 degrees C liposome in normal choroid or CNV were compared. Next, the power settings with 0.5 mm and 0.25 mm spot sizes were compared following administration of 40 degrees C liposome or 46 degrees C liposome. RESULTS: The minimum power values when release from 46 degrees C liposome was observed showed a significant difference in distribution of power values between normal choroid and CNV. CNV required significantly higher power than normal choroid. With 40 degrees C liposome, the power was 9.7 (1.9) mW (mean (SD)) at a spot size of 0.25 mm, and 12.1 (1.6) mW at 0.5 mm, respectively. When using 46 degrees C liposome, the power setting was 10.2 (1.2) mW at a spot size of 0.25 mm, and 14.6 (2.2) mW at 0.5 mm, respectively. CONCLUSIONS: CNV demonstrated varying heat conduction, compared with normal choroid. Laser power required to raise the temperature should not necessarily be doubled, even when the spot size is doubled. Close attention should be given to the selection of power settings when performing TTT for CNV.

Interstitial laser coagulation and biodegradable self-expandable, self-reinforced poly-L-lactic and poly-L-glycolic copolymer spiral stent in the treatment of benign prostatic enlargement.

BACKGROUND AND PURPOSE: Interstitial laser coagulation of the prostate (ILCP) induces necrosis, edema, and an increased risk of postoperative urinary retention. The object here was to evaluate the efficacy, safety, and utility of a new self-expandable self-reinforced (SR) PLGA copolymer(lactic:glycolic ratio 80/20) spiral stent inserted after ILCP to promote voiding. The SR-PLGA stent has a degradation time of 2 to 2.5 months. PATIENTS AND METHODS: Fifty men with a mean age of 70.5 years (range 52-85 years), suffering from lower urinary tract symptoms secondary to benign prostatic enlargement underwent ILCP. A suprapubic catheter was inserted, ILCP performed, and an SR-PLGA 80/20 spiral stent inserted on completion of the operation. The suprapubic catheter was removed when voiding commenced. As prophylactic antibiotic, ciprofloxacin was used in a single dose before ILCP, followed by trimethoprim or nitrofurantoin for 2 weeks. RESULTS: All except three patients started to void on the first postoperative day. In two of the three cases, the stent had moved proximally and had to be relocated, whereafter voiding succeeded. The mean maximum and average flow rates increased, while DAN-PSS-1 symptom score and post voiding residual urine volume decreased statistically significantly. At 2 months, the stent was still intact in the urethra in all except three patients. At 4 months, it had been degraded into small fragments, and at 6 months, it had been completely eliminated. The only exceptions were three patients with an uncalcified piece of the stent in the bladder. Half of the patients had irritative symptoms caused at least partly by ILCP itself; 10% had asymptomatic urinary infection postoperatively. CONCLUSIONS: The self-expandable SR-PLGA copolymer stent is safe and highly biocompatible. It ensures voiding in the case of temporary obstruction caused by prostatic edema. The degradation time is long enough in all patients to cover the need for postprocedure urinary drainage.

Saline soaked pledgets prevent carbon dioxide laser-induced endotracheal tube cuff ignition.

STUDY OBJECTIVE: To determine whether saline soaked pledgets would protect the cuffs of polyvinylchloride (PVC) endotracheal tubes from carbon dioxide (CO2) laser-induced combustion. DESIGN: 12 PVC endotracheal tubes were studied. The cuffed end of each was placed in a graduated cylinder and flushed with 5 L/min of oxygen for 5 minutes. The endotracheal tube's cuff was then inflated with air and the system pressure set to 20 cm H2O. SETTING: Research laboratory of a university hospital. INTERVENTIONS: Six of the endotracheal tube cuffs were protected with 1 inch by 3 inch saline soaked pledgets and six were left unprotected. A CO2 laser set to 40 watts was then fired at the cuffs. MEASUREMENTS AND MAIN RESULTS: All six unprotected cuffs were ignited in less than 1 second. No significant combustion occurred at the six pledget protected endotracheal tube cuffs after 1 minute of laser fire. CONCLUSIONS: Under the conditions of this experiment, saline soaked pledgets protected PVC endotracheal tube cuffs from the CO2 laser.

[Diode laser-induced retinal thermal damage control with a liposome-dye system]. / Contrôle du dommage thermique rétinien induit par laser diode à l'aide d'un système liposomes-colorant.

PURPOSE: To evaluate the feasibility of retinal thermal damage assessment in a rabbit eye model by using laser-induced release of liposome-encapsulated dye. METHODS: After anesthesia, thermosensitive liposomes (DSPC) loaded with 5,6-Carboxyfluorescein were injected intravenously to pigmented rabbits. Retinal photocoagulations were performed with a 810 nm diode laser (p = 100 to 400 mW, phi = 500 microns, 1s) (OcuLight, IRIS Medical Instruments Inc., USA). Fluorescence measurements in the area of the laser exposures were then made with a digitized angiograph (CF-60UVi, Canon-Europe, The Netherlands; OcuLab, Life Science Resources Ltd, England). RESULTS: Fluorescent spots were observed for power ranging from 100 +/- 5 mW to 400 +/- 5 mW. The fluorescence intensity increased linearly with the power and reached a plateau at 300 +/- 5 mW. The fluorescence intensity was correlated to the maximum temperature at the center of the laser spot with a linear increase from 42 +/- 3 degrees C to 65 +/- 3 degrees C. These results are consistent with our two previous studies with DSPC liposomes for temperature measurements in a tissue model and then in a vascular model. CONCLUSION: This preliminary study demonstrates the possibility of a laser-induced release of liposome-encapsulated dye for a quantification of diode laser induced thermal damage in ophthalmology. Such a method could be useful for a real-time monitoring of laser photocoagulation for conditions such as choroidal neovascular membranes when a precise thermal damage is required near the foveolar area.

Comparison of long-acting bevacizumab formulations in the treatment of choroidal neovascularization in a rat model.

OBJECTIVE: The objective of this study was to compare the reduction in size of experimentally induced choroidal neovascularization (CNV) in rat eyes treated with bevacizumab, poly(ethylene-glycol) (PEG)-bevacizumab conjugate (b-PEG), and poly(lactic-co-glycolic acid) (PLGA)-encapsulated bevacizumab (b-PLGA). METHODS: Forty-eight eyes from 24 rats were divided into 4 groups of 12 eyes. In each group, 3 eyes were assigned to a treatment subgroup, each receiving a different injection-control, bevacizumab, b-PEG, and b-PLGA. In all eyes, laser photocoagulation was used to rupture Bruch's membrane. In group 1, laser was followed by injection, which was then followed by harvesting the rats to assess the CNV area. All 3 steps were separated by a 2-week interval. In groups 2, 3, and 4, injection preceded laser photocoagulation by a variable interval and all rats were harvested 2 weeks postlaser treatment. In group 2, laser and injection were separated by 2 weeks. In group 3, laser followed injection by 4 weeks. In group 4, laser followed injection by 6 weeks. The CNV area was measured for each subgroup and compared against its control. Pairwise comparisons were conducted to assess for statistically significant differences between subgroups. RESULTS: All subgroups in groups 1, 2, and 4 showed statistically significant reduction of CNV area (P<0.05). In group 3, the b-PEG and b-PLGA subgroups showed a 9.0% (P=0.384) and 20.3% (P=0.077) reduction in CNV area versus control, whereas there was no reduction in CNV area in the bevacizumab subgroup. However, this was not found to be statistically significant. In group 4, b-PEG was more effective than bevacizumab and b-PLGA. CONCLUSION: The reduction in CNV area in all treatment subgroups, with the exception of those in group 3, suggests successful creation of the 2 bevacizumab formulations while retaining its active antiangiogenic properties. Further studies varying in dosages and timing of injection and laser are needed to evaluate the formulations' long-acting efficacy.

Retinal detachment after silicone oil removal is prevented by 360 degrees laser treatment.

AIM: To investigate the effect of 360 degrees laser retinopexy on the incidence of retinal detachment (RD) after silicone oil removal. METHODS: In a prospective, randomised clinical trial, 303 patients (303 eyes) affected with primary (n = 211) or recurring (n = 92) rhegmatogenous RD treated by vitrectomy with silicone oil (1000 cSt) and endolaser photocoagulation of retinal breaks were randomised to receive 360 degrees laser retinopexy or not. After at least 4 months, in eyes with a fully attached retina, the silicone oil was removed. The incidence of RD after silicone oil removal was evaluated. RESULTS: 151 eyes received 360 degrees laser retinopexy (completed intraoperatively in 93 eyes and postoperatively in 58 eyes, in nine of them after cataract extraction); 152 eyes served as controls. Silicone oil was removed from 139 laser-treated eyes (92.05%) and 129 controls (84.87%; NS). In the first group, 12 eyes (8.63%) developed an RD posterior to laser treatment (including the macula), three eyes (2.16%) had a localised posterior RD (treated by laser), and 14 (10.07%) had an RD anterior to the laser treatment. In the control group, RD occurred in 27 eyes (20.93%; p = 0.007). CONCLUSIONS: 360 degrees laser retinopexy reduces the incidence of RD after silicone oil removal; it should be completed intraoperatively.

A preliminary clinical and histopathological study of laser skin resurfacing using a frequency-doubled Nd:YAG laser after application of Chromofilm.

BACKGROUND AND OBJECTIVES: Carbon dioxide (CO2) and Er:YAG lasers are commonly used for laser skin resurfacing. In demonstrating their efficacy, intra- and interoperator variability may be important. In attempting to solve this problem, a new concept was developed which combines a previous application of an exogenous chromophore onto the skin in a standardized way (Chromofilm) and irradiation with a millisecond, low-power pulsed laser. MATERIALS AND METHODS: This study aimed to evaluate this new concept in vivo in human skin using a 532-nm Nd:YAG laser connected to a scanner using the following parameters: 532 nm, 2W, 1-mm spot size, 30-mm2 hexagonal surface irradiation and 50-120-ms pulse duration. The laser irradiation was performed both 15 h and 1 h prior to the facelift procedure. Tissue samples were examined histologically to determine the injury depth using nitroblue-tetrazolium chloride (NBTC) staining, haematoxylin-eosin staining and Masson's staining. RESULTS: Morphometric analysis of histological preparations showed that the depth of injury was dose-dependent: 50-ms pulse duration induced total epidermis ablation and fine dermal coagulation; 120-ms pulse duration induced dermal coagulation down to 120 microns. No residual carbon film was observed on histologic sections. CONCLUSION: Laser skin resurfacing using a 532-nm laser irradiation after application of a carbon film transfer is an effective method for skin resurfacing. With this new galenic approach (Chromofilm), the control of all parameters (thickness, chromophore concentration and distribution) can be achieved to predict the thermal injury obtained after laser irradiation.

Biodegradable self-reinforced polyglycolic acid spiral stent in prevention of postoperative urinary retention after visual laser ablation of the prostate-laser prostatectomy.

PURPOSE: The efficacy and safety of a new biodegradable (self-reinforced polyglycolic acid) spiral stent in securing free voiding despite edema after visual laser ablation of the prostate were studied. MATERIALS AND METHODS: A biodegradable spiral stent was inserted into the prostatic urethra in 22 patients immediately after visual laser ablation of the prostate. Uroflowmetry, measurement of residual urine volume, urine culture, cystoscopy and assessment of symptomatic improvement were done before, and 1, 3 and 6 months after visual laser ablation of the prostate. RESULTS: All 22 patients voided freely on day 1 or 2 after visual laser ablation of the prostate. However, 4 patients later had urinary retention due to a short spiral or too rapid spiral degradation. Half of the patients experienced a transient decrease in flow with some obstructive symptoms at 3 weeks that lasted 1 to 2 weeks. At 4 weeks all spirals were degraded and 3 patients had a positive urine culture. The maximum flow rate increased and the residual urine volume decreased significantly concomitantly with significant symptomatic improvement. CONCLUSIONS: The self-reinforced polyglycolic acid spiral stent can effectively and safely prevent postoperative urinary retention after visual laser ablation of the prostate.

Expansion and bioabsorption of the self-reinforced lactic and glycolic acid copolymer prostatic spiral stent.

PURPOSE: Self-reinforced bioabsorbable stents can be made self-expanding due to the viscoelastic memory of the oriented bioabsorbable materials. A new self-expandable self-reinforced copolymer of lactic/glycolic acid, lactic/glycolic molar ratio 80:20 stent was developed to prevent postoperative urinary retention after procedures that induced prostatic edema. In in vitro experiments the expansion rate has been up to 100% during the first few hours at body temperature. We investigated the expansion rate and biodegradation of the self-reinforced lactic and glycolic acid copolymer prostatic spiral stent in vivo in the prostatic urethra. MATERIALS AND METHODS: A total of 39 men, 52 to 84 years old, with lower urinary tract symptoms due to benign prostatic enlargement underwent interstitial laser coagulation of the prostate. A self-reinforced copolymer of lactic/glycolic acid, lactic/glycolic molar ratio 80/20 stent was inserted into the prostatic urethra at the end of the operation. The stent lumen diameter was 4.5 mm. The location and diameter of the lumen and degradation of the stent were studied with transrectal ultrasound at 1, 2, 4 and 6 months postoperatively. At 6 months patients underwent cystoscopy. RESULTS: All except 1 patient voided on postoperative day 1. Mean lumen diameter was 7.4 mm. (range 6.2 to 8.2) at 1 month and 7.2 mm (range 6.2 to 7.5) at 2 months. At 4 months the stent was degraded into small pieces. No pieces of stent were found in the prostatic urethra on ultrasound or cystoscopy at 6 months. However, a portion of the spiral stent was found at the bottom of the bladder in 2 patients. CONCLUSIONS: The speed and expansion rate of the self-reinforced copolymer of lactic/glycolic acid, lactic/glycolic molar ratio 80/20 stent was sufficient to lock the stent in place and ensure voiding in cases of edema induced bladder outlet obstruction. Strength retention greater than 2 months was long enough to avoid later impairments of voiding.

Thermal damage assessment of blood vessels in a hamster skin flap model by fluorescence measurement of a liposome-dye system.

BACKGROUND AND OBJECTIVES: The present study was undertaken to evaluate the feasibility of thermal damage assessment of blood vessels by using laser-induced release of liposome-encapsulated dye. STUDY DESIGN/MATERIALS AND METHODS: Experiments were performed in a hamster skin flap model. Laser irradiation was achieved with a 300 microm fiber connected to a 805 nm diode laser (power = 0.8W, spot diameter = 1.3 mm and pulse exposure time lasting from 1 to 6 s) after potentiation using a specific indocyanine green (ICG) formulation (water and oil emulsion). Liposomes-encapsulated carboxyfluorescein were prepared by the sonication procedure. Carboxyfluorescein (5,6-CF) was loaded at high concentration (100 mM) in order to quench its fluorescence. The measurements were performed after i.v. injection of DSPC liposomes (1.5 ml) and lasted 40 min. Fluorescence emission was measured with an ultra high sensitivity intensified camera. RESULTS: Three different shapes of fluorescent spots were identified depending on target (blood vessel or skin) and energy deposition in tissue: (i) intravascular fluorescence, (ii) transient low fluorescence circular spot, and (iii) persistent high intense fluorescence spot. These images are correlated with histological data. CONCLUSION: Real-time fluorescence imaging seems to be a good tool to estimate in a non-invasive manner the thermal damage induced by a diode laser combined with ICG potentiation.

Diode laser-induced thermal damage evaluation on the retina with a liposome dye system.

BACKGROUND AND OBJECTIVES: The aim of the study was to evaluate the feasibility of retinal thermal damage assessment in a rabbit eye model by using laser-induced release of liposome-encapsulated dye. STUDY DESIGN/MATERIALS AND METHODS: After anesthesia, thermosensitive liposomes (DiStearoyl Phosphatidyl Choline: DSPC) loaded with 5,6-carboxyfluorescein were injected intravenously to pigmented rabbits. Retinal photocoagulations were performed with a 810nm diode laser (P=100-400 mW, laser spot=500 microm, 1s) (OcuLight, IRIS Medical Instruments, Mountain View, CA). Fluorescence measurements in the area of the laser exposures were then realized with a digitized angiograph (CF-60UVi, Canon-Europe, The Netherlands; OcuLab, Life Science Resources, UK). RESULTS: Fluorescent spots were observed for power ranging from 100 +/- 5 mW to 400 +/- 5 mW. The fluorescence intensity increased linearly with the power and reached a plateau at 280 +/- 5 mW. The fluorescence intensity was correlated to the maximum temperature at the center of the laser spot with a linear increase from 42 +/- 3 degrees C to 65 +/- 3 degrees C. These results are in agreement with our two previous studies with DSPC liposomes for temperature measurements in a tissue model and then in a vascular model. CONCLUSION: This preliminary study demonstrates the possibility of a laser-induced release of liposome-encapsulated dye for a quantification of diode laser induced thermal damage in ophthalmology. Such a method could be useful for a real-time monitoring of laser photocoagulation for conditions such as choroidal neovascular membranes when a precise thermal damage is required near the foveolar area.