Discovery and insights from DSX mission's high-power VLF wave transmission experiments in the radiation belts.

Space weather phenomena can threaten space technologies. A hazard among these is the population of relativistic electrons in the Van Allen radiation belts. To reduce the threat, artificial processes can be introduced by transmitting very-low-frequency (VLF) waves into the belts. The resulting wave-particle interactions may deplete these harmful electrons. However, when transmitting VLF waves in space plasma, the antenna, plasma, and waves interact in a manner that is not well-understood. We conducted a series of VLF transmission experiments in the radiation belts and measured the power and radiation impedance under various frequencies and conditions. The results demonstrate the critical role played by the plasma-antenna-wave interaction around high-voltage space antennae and open the possibility to transmit high power in space. The physical insight obtained in this study can provide guidance to future high-power space-borne VLF transmitter developments, laboratory whistler-mode wave injection experiments, and the interpretation of various astrophysical and optical phenomena.

Postoperative pain after glide path preparation using manual, reciprocating and continuous rotary instruments: a randomized clinical trial.

AIM: To compare the incidence, intensity and prediction of postoperative pain after glide path preparation with manual, continuous rotary and a novel reciprocating glide path instrument. METHODOLOGY: The study included 240 patients, who were treated by four specialists according to a planned treatment protocol. Following access cavity preparation and prior to glide path preparation, the subjects were randomly assigned to one of the three groups according to the glide path instrument by choosing a sealed envelope containing the group name: R-Pilot (VDW, Munich, Germany), ProGlider (Dentsply Sirona, Ballaigues, Switzerland) and stainless steel K-files (Dentsply Sirona; n = 80). Following glide path preparation, the teeth underwent standardized single visit root canal treatment procedures. The root canals were chemomechanically prepared using the ProTaper Next rotary system (Dentsply Sirona) under copious irrigation with 5.25% NaOCl. Final irrigation was performed with 17% EDTA and distilled water. Root fillings were placed using an epoxy resin sealer and gutta-percha with a cold lateral compaction technique. After coronal restorations were placed, the patients were discharged with a questionnaire about the incidence and intensity of pain at 6, 12, 18, 24, 48 and 72 h postoperatively. The data were analysed using chi-square, anova and Tukey tests and logistic regression analysis. RESULTS: The presence of preoperative pain (OR ranged between 3.5 and 14.3) and the glide path preparation techniques (OR between 2.2 and 4.1) were associated with significant effects on the incidence of postoperative pain when comparing manual versus engine-driven glide path preparation (P < 0.05). Patients in the R-Pilot (Mean VAS ranged between 1.57-0.21) and ProGlider (1.97-0.28) groups reported significantly less postoperative pain scores than those in the manual group (2.82-1.32; P < 0.05). There was no significant difference between R-Pilot and ProGlider groups regarding the postoperative pain scores (P > 0.05). CONCLUSION: Preparation of glide paths with rotating or reciprocating NiTi instruments was associated with less postoperative pain levels and incidence compared to manual glide path preparation with no significant difference between rotating and reciprocating instruments. Preoperative pain was the most significant predictor for the occurrence of postoperative pain.

Effect of interrupted motion on the cyclic fatigue resistance of reciprocating nickel-titanium instruments.

AIM: To compare the cyclic fatigue resistances of WaveOne Gold (Denstply Sirona, Ballaigues, Switzerland), WaveOne (Dentsply Sirona) and Reciproc (VDW, Munich, Germany) in interrupted reciprocation. METHODOLOGY: Three groups of 18 instruments each of WaveOne Gold Primary, WaveOne Primary and Reciproc R25 were subjected to cyclic fatigue tests in reciprocation and interrupted reciprocation. The instruments in group 1 were tested in reciprocation, whereas in groups 2 and 3, reciprocation was interrupted for 1 s in every 5 s and 10 s, respectively. Cyclic fatigue resistance was tested using dynamic test devices in stainless steel, curved canals (60°, r = 5 mm) until fracture, and the time to fracture values were recorded. The lengths of the fractured tips were also recorded, and fractured surfaces were examined with a scanning electron microscope (SEM). Data were evaluated by one-way analysis of variance and Tukey's tests. RESULTS: The cyclic fatigue resistance of WaveOne Gold Primary was not affected by the interruptions (P > 0.05) and exhibited significantly greater cyclic fatigue resistance than WaveOne Primary and Reciproc R25 in all groups (P < 0.05). Interruptions reduced the cyclic fatigue resistance of WaveOne Primary and Reciproc R25 significantly (P < 0.05). CONCLUSION: Interrupted reciprocation reduced the cyclic fatigue resistance of Reciproc R25 and WaveOne Primary. The cyclic fatigue resistance of WaveOne Gold Primary was greater than that of WaveOne Primary and was not dependent on the occurrence of interruptions.

Multicenter study of pars plana vitrectomy for optic disc pit maculopathy: MACPIT study.

PurposeTo evaluate surgical intervention with pars plana vitrectomy (PPV) for correction of optic disc pit maculopathy (ODP-M).Patients and methodsRetrospective chart review from 13 centres of 51 eyes of 50 patients with ODP-M who underwent PPV between 2002-2014. Anatomic and final best-corrected visual acuity (BCVA) outcomes were evaluated for all cases with different adjuvant techniques.ResultsThere were 23 males and 27 females with median age 25.5 (6-68) years. Preoperative median foveal thickness was 694.5 (331-1384) µm and improved to 252.5 (153-1405) µm. Median BCVA improved from 20/200 (20/20000 to 20/40) to 20/40 (20/2000 to 20/20) with 20/40 or better in 31 eyes. Complete retinal reattachment was achieved in 44 eyes (86.3%) at 7.1 (5.9) months. The good surgical outcomes were achieved in different adjuvant groups. Median follow-up was 24 (6 to 120) months.ConclusionsThese results confirm the long-term effectiveness of PPV for ODP-M. Prospective studies are needed to determine the effectiveness of any adjuvant technique in improving the success of PPV for ODP-M.

Evaluation of surface characteristics of rotary nickel-titanium instruments produced by different manufacturing methods.

BACKGROUND: Instrument fracture is a serious concern in endodontic practice. OBJECTIVE: The aim of this study was to investigate the surface quality of new and used rotary nickel-titanium (NiTi) instruments manufactured by the traditional grinding process and twisting methods. MATERIALS AND METHODS: Total 16 instruments of two rotary NiTi systems were used in this study. Eight Twisted Files (TF) (SybronEndo, Orange, CA, USA) and 8 Mtwo (VDW, Munich, Germany) instruments were evaluated. New and used of 4 experimental groups were evaluated using an atomic force microscopy (AFM). New and used instruments were analyzed on 3 points along a 3 mm. section at the tip of the instrument. Quantitative measurements according to the topographical deviations were recorded. The data were statistically analyzed with paired samples t-test and independent samples t-test. RESULTS: Mean root mean square (RMS) values for new and used TF 25.06 files were 10.70 ± 2.80 nm and 21.58 ± 6.42 nm, respectively, and the difference between them was statistically significant (P < 0.05). Mean RMS values for new and used Mtwo 25.06 files were 24.16 ± 9.30 nm and 39.15 ± 16.20 nm respectively, the difference between them also was statistically significant (P < 0.05). CONCLUSION: According to the AFM analysis, instruments produced by twisting method (TF 25.06) had better surface quality than the instruments produced by traditional grinding process (Mtwo 25.06 files).

Effect of posterior subtenon injection of 40 mg of triamcinolone acetonide on glycemic control and serum cortisol and adrenocorticotropic hormone in diabetic patients.

OBJECTIVE: To evaluate the influence of posterior subtenon injection of 40 mg of triamcinolone acetonide (TA) on blood glucose, cortisol and adrenocorticotrophic hormone (ACTH) in patients with clinically significant diabetic macular oedema. PATIENTS AND METHODS: This prospective clinical study included 33 type 2 diabetic patients assigned to receive subtenon injection of 40 mg of TA (study group: 20 patients, 9 women and 11 men, mean age 60.8 ± 10.1 years) or subtenon injection of 1 ml of saline solution (control group: 13 patients, 7 women and 6 men, mean age 57.9 ± 7.5 years) as an adjunct to focal/grid laser therapy. Pre-injection laboratory tests consisted of fasting blood glucose (FBG), glicolised hemoglobin (HbA1c), fructosamine, ACTH and cortisol. Post-injection measurements were performed in a following schedule: FBG in day 1; FBG, ACTH and cortisol at week 1; FBG, fructosamine, ACTH and cortisol at month 1, 2 and 3. HbA1c was also measured at 3 months. The mean ± SD values of groups at each visit were compared. The time-related changes in the parameters in each group were also analyzed using SPSS (Statistical Package for Social Sciences) for Windows 15.0 software. RESULTS: Pre-injection FBG, HbA1c, fructosamine, ACTH and cortisol were similar in both groups (p > 0.05 for all). Pre-injection and final HbA1c values were similar in the study (8.6% ± 1.9 and 8.7% ± 1.8, respectively) and control groups (8.6% ± 1.7 and 8.5% ± 1.8, respectively) (p > 0.05 for all). None of the patients had a decrease in plasma cortisol that decreased below normal values at either time point. There was no statistically significant difference between groups and between each visit in groups according to FBG levels, blood fructosamine, ACTH and cortisol levels (p > 0.05 for all). No adverse event was observed. CONCLUSIONS: Subtenon injection of 40 mg of TA does not increase blood sugar levels significantly, and it does not suppress blood cortisol or ACTH levels at 1 week or later in patients with diabetes mellitus. Subtenon injection of 40 mg TA seems to be safe in respect to elevation of blood sugar levels or systemic corticosteroid pathways.

Long-term outcomes of pars plana vitrectomy without internal limiting membrane peeling for optic disc pit maculopathy.

PURPOSE: To evaluate the results of surgical treatment of maculopathy secondary to congenital optic pit anomaly with pars plana vitrectomy (PPV), endolaser to the temporal edge of the optic disc and C3F8 tamponade without internal limiting membrane (ILM) peeling. PATIENTS AND METHODS: Thirteen eyes of 12 patients with serous macular detachment and/or macular retinoschisis secondary to congenital optic disc pit (ODP) were included in the study. All eyes underwent PPV, posterior hyaloid removal, endolaser photocoagulation on the temporal margin of the optic disc and 12% C3F8 gas tamponade. Anatomic success and functional outcome determined retrospectively by optical coherence tomography and measurement of best corrected visual acuity (BCVA), respectively were the main outcome parameters. RESULTS: Two lines or more improvement in BCVA was obtained in 11 eyes and 6 of these eyes had 20/40 or better BCVA at the final visit. Subretinal or intraretinal fluid was completely resorbed postoperatively in 12 eyes but a little intraretinal fluid persisted in one eye at the 16-month follow-up. Better visual improvement was observed in patients treated by earlier surgical intervention. CONCLUSION: PPV, C3F8 gas tamponade and endolaser to the optic disc margin without ILM peeling may yield favourable results in the treatment of ODP maculopathy.

Evaluation of the change in accommodation amplitude in subjects with pseudoexfoliation.

PURPOSE: To evaluate the changes in accommodation amplitude in cases with pseudoexfoliation. MATERIALS AND METHODS: Twenty-nine eyes having pseudoexfoliation and 37 normal eyes aged between 40-60 years were included in the study. After ophthalmic examination, accommodation amplitude was measured using Powerrefractor II. Besides, axial length, anterior chamber depth, and lens thickness was measured by A-scan ultrasonography. The results obtained were evaluated by independent samples' t-test. RESULTS: There was no difference in mean age between cases with pseudoexfoliation and normal cases (P=0.131). Mean accommodation amplitude was significantly lower in cases with pseudoexfoliation (P=0.002). Axial length, anterior chamber depth, and lens thickness measurements did not show significant change between groups (P=0.55, P=0.66, P=0.36, respectively). CONCLUSION: In the presence of pseudoexfoliation, ciliary apparatus can be affected and accommodation amplitude can be decreased in earlier ages.

Observations of Earth space by self-powered stations in Antarctica.

Coupling of the solar wind to the Earth magnetosphere/ionosphere is primarily through the high latitude regions, and there are distinct advantages in making remote sensing observations of these regions with a network of ground-based observatories over other techniques. The Antarctic continent is ideally situated for such a network, especially for optical studies, because the larger offset between geographic and geomagnetic poles in the south enables optical observations at a larger range of magnetic latitudes during the winter darkness. The greatest challenge for such ground-based observations is the generation of power and heat for a sizable ground station that can accommodate an optical imaging instrument. Under the sponsorship of the National Science Foundation, we have developed suitable automatic observing platforms, the Automatic Geophysical Observatories (AGOs) for a network of six autonomous stations on the Antarctic plateau. Each station housed a suite of science instruments including a dual wavelength intensified all-sky camera that records the auroral activity, an imaging riometer, fluxgate and search-coil magnetometers, and ELF/VLF and LM/MF/HF receivers. Originally these stations were powered by propane fuelled thermoelectric generators with the fuel delivered to the site each Antarctic summer. A by-product of this power generation was a large amount of useful heat, which was applied to maintain the operating temperature of the electronics in the stations. Although a reasonable degree of reliability was achieved with these stations, the high cost of the fuel air lift and some remaining technical issues necessitated the development of a different type of power unit. In the second phase of the project we have developed a power generation system using renewable energy that can operate automatically in the Antarctic winter. The most reliable power system consists of a type of wind turbine using a simple permanent magnet rotor and a new type of power control system with variable resistor shunts to regulate the power and dissipate the excess energy and at the same time provide heat for a temperature controlled environment for the instrument electronics and data system. We deployed such systems and demonstrated a high degree of reliability in several years of operation in spite of the relative unpredictability of the Antarctic environment. Sample data are shown to demonstrate that the AGOs provide key measurements, which would be impossible without the special technology developed for this type of observing platform.

Long-term results of excision of plaque-like foveal hard exudates in patients with chronic diabetic macular oedema.

OBJECTIVE: To analyse the long-term results of surgical removal of plaque-like diabetic foveal hard exudates. METHODS: In this retrospective, interventional, non-randomized, controlled study, vitrectomy and excision of submacular hard exudates was performed on 11 eyes of 11 patients with plaque-like hard exudates. The mean preoperative LogMAR best corrected visual acuity (BCVA) and exudate diameter were 1.35+/-0.3 and 1.19 disks (range, 0.5-1.8), respectively. In the control group, which consisted of 10 eyes of 7 patients who refused the surgery, baseline mean BCVA and exudate diameter were 1.06+/-0.2 and 1.2 disks (range, 0.7-2.0), respectively. Main outcome measures included BCVA, fundus photography, and surgical complications. RESULTS: The mean follow-up was 39.1+/-3.2 months for the study group and 32.5+/-3.6 months for the control group. In the study group, BCVA improved in 8 (73%) eyes at the final examination. The mean final BCVA was 1.08+/-0.4 (P=0.021). Macular oedema and exudates resolved completely in all eyes. In the control group, final LogMAR visual acuity declined to 1.53+/-0.1 (P=0.005). Macular pigment epithelium atrophy or scar formation was observed in 7 (64%) eyes in the study group and in all eyes in the control group. CONCLUSION: Surgical excision of plaque-like foveal hard exudates resulted in better anatomical and functional outcome when compared to observation alone.

Evaluation of arteriovenous crossing sheathotomy for decompression of branch retinal vein occlusion.

PURPOSE: To report the effects of arteriovenous adventitial sheathotomy on anatomical and functional improvements in patients with macular oedema due to branch retinal vein occlusion (BRVO). METHODS: Pars plana vitrectomy and arteriovenous sheathotomy was performed on 11 patients with BRVO who had vision loss due to macular oedema. Ten patients with macular oedema due to BRVO and who have been treated with grid laser photocoagulation were included in the control group. The measurement of visual acuity with ETDRS chart was taken preoperatively and at 1, 3, 6, and 9 months follow-up in the study group and at 1, 3, 6, and 9 months after grid laser in the control group. RESULTS: The mean preoperative logMAR visual acuity was 0.84+/-0.3 in the surgical group and 1.06+/-0.4 in the control group. The postoperative mean logMAR visual acuity was 0.41+/-0.2, 0.40+/-0.2, 0.40+/-0.3, and 0.36+/-0.3 at 1, 3, 6, and 9 months follow-up, respectively. In the control group the postlaser mean logMAR visual acuity was 0.92+/-0.3, 0.87+/-0.4, 0.85+/-0.3, and 0.82+/-0.3 at 1, 3, 6, and 9 months follow-up, respectively. The improvements of visual acuity in both groups were statistically significant when compared to pretreatment (P=0.003 and P=0.007 at 9 months in the study and control group, respectively). CONCLUSION: Arteriovenous sheathotomy for decompression of BRVO in patients who have vision loss due to macular oedema was safe and effective for anatomical and functional improvement and resulted in significantly better visual outcomes than a matched control group of laser-treated eyes.

[Does the cilioretinal artery affect age-related macular degeneration?]. / Können zilioretinale Arterien altersabhängige Makuladegeneration beeinflussen?

PURPOSE: The aim of this study was to investigate the influence of the cilioretinal artery (CRA) on eyes with age-related macular degeneration (AMD). METHODS: One hundred and seventy-five eyes with AMD and 170 eyes without AMD as a control were included in the study. The prevalence of a CRA was compared between the control subjects and the patients with AMD. RESULTS: A CRA was established in 20.6 % of eyes that did not have AMD. 12.5 % of eyes with AMD had a CRA (p = 0.045). A CRA was observed in 13.6 % of eyes with wet AMD, in 10.5 % of eyes with dry AMD and in 19.2 % of eyes with drusen. CONCLUSION: The presence of CRA may have protective effects against the development of AMD.

Canal preparation with Hero 642 rotary Ni-Ti instruments compared with stainless steel hand K-file assessed using computed tomography.

AIM: To compare ex vivo root canal preparation with conventional stainless steel K-files and Hero 642 rotary Ni-Ti instruments. METHODOLOGY: Mesiobuccal canals of 20 maxillary first molars (with angles of curvature between 25 degrees and 35 degrees ) were used. After preparation with Hero 642 rotary instruments and stainless steel K-files, the amount of transportation that occurred was assessed using computed tomography. The teeth were scanned by computed tomography before instrumentation. One millimetre thick slices were prepared from the apical end point to the pulp chamber. The first two sections were 3 mm from the apical end of the root (apical level) and 3 mm below the orifice (coronal level). A further section (mid-root level) was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. Ten teeth were instrumented using Hero 642 rotary instruments and another 10 teeth were instrumented using stainless steel K-files. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross-sectional images taken prior to canal preparation. Amount of transportation and centreing ability was assessed. Student's t-test was used for statistical analysis. RESULTS: Less transportation occurred with Hero 642 rotary instruments than stainless steel K-files at the mid-root and coronal levels (mid-root: P < 0.05 and coronal: P < 0.001). Hero 642 rotary instruments had better centreing ability than K-files at all three levels (apical: P < 0.05, mid-root: P < 0.05 and coronal: P < 0.001). CONCLUSIONS: Hero 642 rotary instruments transported canals less, especially at the middle and coronal thirds of the root canals than stainless steel K-files. Hero 642 instruments had better centreing ability.

Comparing the effects of travoprost and brinzolamide on intraocular pressure after phacoemulsification.

PURPOSE: To evaluate the intraocular pressure (IOP) lowering effect of travoprost and brinzolamide within the first 24 h after phacoemulsification cataract surgery. METHODS: This prospective, randomized, double-masked, controlled study comprised 90 eyes of 90 consecutive patients with senile cataract who had uneventful phacoemulsification surgery. Eyes in the first group received travoprost 0.0015%, second group received brinzolamide 1%. Eyes in the third group received balanced salt solution and were used as control. One drop was instilled immediately after surgery. IOP was measured 24 h preoperatively, 6 and 24 h postoperatively. Analysis of variance, Student's-t and chi2-tests were used for statistical analyses. RESULTS: Preoperatively IOP was not significantly different among the three groups (P = 0.653). At 6 and 24 h postoperatively IOP was lower in both travoprost and brinzolamide group when compared to control group (P = 0.018 and 0.015 at 6 h, P = 0.010 and 0.007 at 24 h between travoprost and brinzolamide group was not significant (P = 0.744 at 6 h and P = 0.672 at 24 h). CONCLUSION: Both travoprost and brinzolamide significantly lowered IOP after small incision phacoemulsification cataract surgery within the first 24 h without any side effect.

Effect of topical dexamethasone and ciprofloxacin on bacterial flora of healthy conjunctiva.

PURPOSE: To investigate the effects of topical dexamethasone and ciprofloxacin, alone and in combination, on the colony counts of conjunctival bacterial flora of healthy subjects. METHODS: A total of 100 healthy subjects were randomly divided into four groups, consisting of 25 subjects each. Group 1 was treated with dexamethasone phosphate 0.1% (Maxidex). Group 2 was treated with ciprofloxacin 0.3% (Ciloxan) and Group 3 with a combination of these drugs. Group 4 received artificial tear solution (Tears Naturale) and served as control. The drops were administered one drop every 1 min. A pretreatment culture and recultures at 30, 90, and 180 min after application of final drops were performed on all subjects. The bacterial growth was evaluated in a quantitative manner. All cultures were performed in a double-masked fashion. ANOVA test was used for statistical analyses. RESULTS: While there was no significant difference among mean number of pretreatment colonies between the groups (P=0.85); the differences at 30, 90, and 180 min were statistically significant (P<0.001). During the study there was no statistically significant change in colony counts in Groups 1 and 4 (P=0.66 and 0.55, respectively). The colony count numbers decreased significantly at 30 and 90 min in Group 2 (P<0.001 and P=0.004) and at 30 min in Group 3 (P=0.002). CONCLUSION: Topically applied dexamethasone did not cause a significant change in colony counts of the healthy conjunctiva. Both ciprofloxacin and a combination of ciprofloxacin and dexamethasone were effective in the reduction of bacterial ocular flora.

Comparing the efficacy and safety of phacoemulsification in white mature and other types of senile cataracts.

AIM: To compare the intraoperative difficulty and postoperative outcome in patients who have white mature cataract in one eye and other types of senile cataract in the other eye undergoing clear corneal phacoemulsification and foldable intraocular lens implantation. METHODS: 82 patients who had white mature cataract in one eye, posterior subcapsular, cortical, nuclear, or mixed type cataract in the other eye were enrolled in this prospective study. Postoperative outcomes, intraoperative difficulties related to capsulorhexis, and phacoemulsification were analysed between the two groups of eyes. Postoperative examinations were done at 1 day, 1 week, 1 and 3 months. RESULTS: Postoperative visual acuity, central corneal thickness, intraocular pressure, and rate of posterior capsule rupture were not significantly different between the two group of eyes (p>0.05). Mean effective phaco time, frequency of postoperative corneal oedema and posterior capsular plaque were found to be significantly higher in the mature cataract group (p<0.05). CONCLUSIONS: A one stage, 5 mm continuous capsulorhexis was achieved using trypan blue and generous amounts of retentive viscoelastic agent in eyes with white mature cataract. Intraoperative difficulties and postoperative outcome of clear corneal incision phacoemulsification surgery and foldable intraocular lens implantation were similar in white mature and other types of senile cataract. Topical anaesthesia in phacoemulsification of eyes with white mature cataract is safe and well tolerated.

Effectiveness of oxygenation and suction in cataract surgery: is suction of CO2-enriched air under the drape during cataract surgery necessary?

PURPOSE: To investigate the effectiveness of aspiration of expired air by a suction system on peripheral oxygen saturation (SpO(2)) and end tidal carbon dioxide (EtCO(2)) during cataract surgery. MATERIALS AND METHODS: In total, 160 pre-medicated patients aged between 40 and 70 years (ASA I-III, classification of patients according to the American Society of Anesthesiologists) scheduled for cataract surgery under retrobulbar or peribulbar block were examined in a randomised, single-blind manner. The patients were sedated with 3 mg midazolam i.v. 15 min before operation and were monitored with an anaesthesia monitor. Heart rate (HR), non-invasive mean arterial pressure (MAP), SpO(2) and EtCO(2) were continuously measured using a standardised monitor. The first group (non-suction group, n = 80) received 4 L min(-1) O(2) with nasal cannule while the second group (suction group, n = 80) received 4 L min(-1) O(2) with nasal cannule, and the expired air was aspired with a Y-piece suction system. EtCO(2) was measured with the line of the sampling tube in the anaesthesia monitor. Respiratory rate (RR) was counted for a period of 1 min at each measurement time with thoracic excursions. The results were evaluated by unpaired t-test and analysis of variance. RESULTS: Severe reduction of SpO(2) and raising of EtCO(2) were observed significantly in the first group during the operation. RR, HR and MAP increased due to hypoxaemia. In the second group, SpO(2) was stabilised at high levels and EtCO(2) did not increase. RR, HR and MAP levels remained within the normal limits. Differences between the two groups were statistically significant (P < 0.05). CONCLUSION: During cataract surgery with local anaesthesia, SpO(2) decreases and RR, HR and MAP increase because of reinspiration of expired air under the drape. Insufflation of O(2) and aspiration of expired air with a suction system have prevented severe reduction of SpO(2) and raising of EtCO(2). It was suggested that O(2) delivery and use of an aspiration system decreased the risk of hypoxaemia significantly in the patients undergoing the cataract surgery.

Prevention of posterior capsule opacification by retinoic acid and mitomycin.

BACKGROUND: Our aim was to evaluate the effect of an intraoperative single dose of retinoic acid (RA) or mitomycin C (MMC) in preventing posterior capsule opacification (PCO). METHODS: Twenty-seven rabbits were divided randomly into three groups. RA (250 microg/ml) and MMC (0.04 mg/ml) were given 0.1 ml by hydrosection and 0.9 ml into the capsular bag after phacoemulsification. The third group served as a control group. Three months after intervention PCO was graded clinically. Furthermore, proliferation of lens epithelial cells was evaluated histologically. RESULTS: Two eyes developed corneal edema in the MMC group. On clinical assessment, RA and MMC were significantly effective in preventing PCO compared with controls (P<0.005). On histological analysis, there was significantly reduced proliferative activity on posterior capsules in the treatment groups, in contrast to multilayer cells in the control group. CONCLUSION: Intraoperative single-dose administration of RA and MMC significantly prevented the development of PCO in rabbit eyes. The optimal biocompatible dosage must be carefully determined by further investigation.

Penetration of topical and oral ofloxacin into the aqueous and vitreous humor of inflamed rabbit eyes.

PURPOSE: This study aimed to investigate the penetration of topical and oral ofloxacin into aqueous humor and vitreous humor in post-traumatic endophthalmitis model in rabbits. METHODS: A standardized intraocular infection after penetrating injury was made in the right eyes of 16 rabbits. Intraocular infection was induced by intravitreal injection of a suspension of Staphylococcus aureus. The intact left eyes were maintained as controls. The animals were divided randomly into two groups. (1) In the topical group, two drops of ofloxacin 0.3% eyedrops were instilled to both eyes every 30 min for 4 h. (2) In the topical-oral group, two doses of 25 mg/kg of ofloxacin at 12-h intervals were given orally, then the protocol of the first group was applied. Aqueous and vitreous humor samples were taken 30 min after the last drop. Ofloxacin concentrations were measured by using HPLC. RESULTS: Mean aqueous levels of ofloxacin in control eyes were: 3.25 +/- 2.55 microg/ml in topical group. 4.58 +/- 5.39 microg/ml in topical-oral group. Mean aqueous levels in inflamed eyes were: 5.21 +/- 4.55 microg/ml in topical group, 10.34 +/- 8.88 microg/ml in topical-oral group. Mean vitreous levels of ofloxacin in control eyes were: 0.17 +/- 0.07 microg/ml in topical group, 1.30 +/- 1.23 microg/ml in topical-oral group. Mean vitreous levels in inflamed eyes were: 0.35 +/- 0.22 microg/ml in topical group, 3.48 +/- 2.69 microg/ml in topical-oral group. There was no significant difference among the groups (P > 0.05), however. CONCLUSIONS: The result of this study suggests that oral supplementation of ofloxacin to topical instillation increased the ocular levels of ofloxacin in the post-traumatic endophthalmitis model. Mean drug concentrations in aqueous and vitreous humors were above the 90% minimum inhibitory concentrations (MIC90) for most of the common microorganisms causing endophthalmitis in all eyes, except in the vitreous humors of the intact eyes instilled topically.

The effects of prolonged acute use and inflammation on the ocular penetration of topical ciprofloxacin.

PURPOSE: To study the aqueous and vitreous penetration of ciprofloxacin after prolonged acute topical administration and to investigate the effects of inflammation on drug penetration. METHODS: A standardized model of intraocular infection after penetrating injury was made in the right eyes of eight rabbits. The intact left eyes were maintained as the control. Two drops of ciprofloxacin 0.3% eyedrops were instilled topically every 1 h for 7 h to all eyes of the rabbits. Aqueous and vitreous samples (100 microl) were obtained half an hour after the last drop. Instillation was continued for 7 h more and samples were obtained as before. Drug concentrations were measured using HPLC. RESULTS: The mean aqueous humor levels of ciprofloxacin were: in control eyes 1.31 +/- 0.78 microg/ml after 7 h and 1.85 +/- 1.69 microg/ml after 14 h of instillation: in inflamed eyes 2.18 +/- 1.02 microg/ml after 7 h and 2.91 +/- 2.12 microg/ml after 14 h. The mean vitreous humor levels were: in control eyes 0.65 +/- 0.44 microg/ml after 7 h and 0.72 +/- 0.8 microg/ml after 14 h of instillation; in inflamed eyes 0.67 +/- 0.77 microg/ml after 7 h and 1.01 +/- 0.43 microg/ml after 14 h. However, the differences among the groups were not significant (P > 0.05). CONCLUSIONS: Ciprofloxacin penetration into aqueous humor was higher in 14-h topical application than that for 7 h. Inflammation increased the penetration of topical ciprofloxacin into aqueous while administered for 7 h and into both aqueous and vitreous humor while administered for 14 h. c