Prospective comparison of accuracy of intraocular lens calculation formulas in phacovitrectomy: a pilot study in a real-world clinical practice.

PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculations among IOL formulas after phacovitrectomy. METHODS: We prospectively enrolled 206 eyes of 206 patients who underwent 25-gauge phacovitrectomy, without gas tamponade, for macular pathology. Pre-operative optical biometry used the IOLMaster 700 to calculate the IOL power with the new formulas, i.e. the Barrett Universal II (BU II), Emmetropia Verifying Optical version 2.0, Hill-Radial Basis Function (RBF) version 3.0, Kane, and Ladas Super Formula, and conventional formulas, i.e. Haigis, Hoffer Q, Holladay 1, Holladay 2, and Sanders-Retzlaff-Kraff/T (SRK/T). A single-piece foldable IOL was implanted in all cases. Manifest refractions were measured before and 3 months after surgery. RESULTS: The BU II formula showed the lowest standard deviation and mean and median absolute errors and had the highest percentage of eyes with a refractive prediction error within ± 0.25 D. The absolute error was significantly lower with the four new formulas, except the Hill-RBF, than with the Hoffer Q (all p = ≤ 0.010) and Holladay 1 formulas (all p = < 0.010). The absolute error with the BU II formula was also lower than that with the Holladay 2 (p = 0.012) and SRK/T (p = 0.024) formulas. CONCLUSION: Overall, the new IOL formulas, except the Hill-RBF, were superior to some of the conventional formulas for calculating IOL power in phacovitrectomy.

Fetal atomic bomb survivor dosimetry using the J45 series of pregnant female phantoms with realistic survivor exposure scenarios: comparisons to dose estimates in the DS02 system.

A significant source of information on radiation-induced biological effects following in-utero irradiation stems from studies of atomic bomb survivors who were pregnant at the time of exposure in Hiroshima, and to a lesser extent, from survivors in Nagasaki. Dose estimates to the developing fetus for these survivors have been assigned in prior dosimetry systems of the Radiation Effects Research Foundation as the dose to the uterine wall within the non-pregnant adult stylized phantom, originally designed for the dosimetry system DS86 and then carried forward in DS02. In a prior study, a new J45 (Japanese 1945) series of high-resolution phantoms of the adult pregnant female at 8 weeks, 15 weeks, 25 weeks, and 38-weeks post-conception was presented. Fetal and maternal organ doses were estimated by computationally exposing the pregnant female phantom series to DS02 free-in-air cumulative photon and neutron fluences at three distances from the hypocenter at both Hiroshima and Nagasaki under idealized frontal (AP) and isotropic (ISO) particle incidence. In this present study, this work was extended using realistic angular fluences (480 directions) from the DS02 system for seven radiation source terms, nine different radiation dose components, and five shielding conditions. In addition, to explore the effects of fetal position within the womb, four new phantoms were created and the same irradiation scenarios were performed. General findings are that the current DS02 fetal dose surrogate overestimates values of fetal organ dose seen in the J45 phantoms towards the cranial end of the fetus, especially in the later stages of pregnancy. For example, for in-open exposures at 1000 m in Hiroshima, the ratio of J45 fetal brain dose to DS02 uterine wall dose is 0.90, 0.82, and 0.70 at 15 weeks, 25 weeks, and 38-weeks, respectively, for total gamma exposures, and are 0.64, 0.44, and 0.37 at these same gestational ages for total neutron exposures. For organs in the abdominal and pelvic regions of the fetus, dose gradients across gestational age flatten and later reverse, so that DS02 fetal dosimetry begins to underestimate values of fetal organ dose as seen in the J45 phantoms. For example, for the same exposure scenario, the ratios of J45 fetal kidney dose to DS02 uterine wall dose are about 1.09 from 15 to 38 weeks for total gamma dose, and are 1.30, 1.56, and 1.75 at 15 weeks, 25 weeks, and 38 weeks, respectively, for the total neutron dose. Results using the new fetal positioning phantoms show this trend reversing for a head-up, breach fetal position. This work supports previous findings that the J45 pregnant female phantom series offers significant opportunities for gestational age-dependent assessment of fetal organ dose without the need to invoke the uterine wall as a fetal organ surrogate.

Japanese pediatric and adult atomic bomb survivor dosimetry: potential improvements using the J45 phantom series and modern Monte Carlo transport.

The radiation exposure estimates for the atomic bomb survivors at Hiroshima and Nagasaki have evolved over the past several decades, reflecting a constant strive by the Radiation Effects Research Foundation (RERF) to provide thorough dosimetry to their cohort. Recently, a working group has introduced a new series of anatomical models, called the J45 phantom series, which improves upon those currently used at RERF through greater age resolution, sex distinction, anatomical realism, and organ dose availability. To evaluate the potential dosimetry improvements that would arise from their use in an RERF Dosimetry System, organ doses in the J45 series are evaluated here using environmental fluence data for 20 generalized survivor scenarios pulled directly from the current dosimetry system. The energy- and angle-dependent gamma and neutron fluences were converted to a source term for use in MCNP6, a modern Monte Carlo radiation transport code. Overall, the updated phantom series would be expected to provide dose improvements to several important organs, including the active marrow, colon, and stomach wall (up to 20, 20, and 15% impact on total dose, respectively). The impacts were especially significant for neutron dose estimates (up to a two-fold difference) and within organs which were unavailable in the previous phantom series. These impacts were consistent across the 20 scenarios and are potentially even greater when biological effectiveness of the neutron dose component is considered. The entirety of the dosimetry results for all organs are available as supplementary data, providing confident justification for potential future DS workflows utilizing the J45 phantom series.

Comparison of the Therapeutic Effects of [211At]NaAt and [131I]NaI in an NIS-Expressing Thyroid Cancer Mouse Model.

Astatine (211At) is an alpha-emitter with a better treatment efficacy against differentiated thyroid cancer compared with iodine (131I), a conventional beta-emitter. However, its therapeutic comparison has not been fully evaluated. In this study, we compared the therapeutic effect between [211At]NaAt and [131I]NaI. In vitro analysis of a double-stranded DNA break (DSB) and colony formation assay were performed using K1-NIS cells. The therapeutic effect was compared using K1-NIS xenograft mice administered with [211At]NaAt (0.4 MBq (n = 7), 0.8 MBq (n = 9), and 1.2 MBq (n = 4)), and [131I]NaI (1 MBq (n = 4), 3 MBq (n = 4), and 8 MBq (n = 4)). The [211At]NaAt induced higher numbers of DSBs and had a more reduced colony formation than [131I]NaI. In K1-NIS mice, dose-dependent therapeutic effects were observed in both [211At]NaAt and [131I]NaI. In [211At]NaAt, a stronger tumour-growth suppression was observed, while tumour regrowth was not observed until 18, 25, and 46 days after injection of 0.4, 0.8, and 1.2 MBq of [211At]NaAt, respectively. While in [131I]NaI, this was observed within 12 days after injection (1, 3, and 8 MBq). The superior therapeutic effect of [211At]NaAt suggests the promising clinical applicability of targeted alpha therapy using [211At]NaAt in patients with differentiated thyroid cancer refractory to standard [131I]NaI treatment.

Low Tube Voltage Computed Tomography Venography for Patients With Deep Vein Thrombosis of the Lower Extremities　- A Comparison With Venous Ultrasonography.

BACKGROUND: Low tube voltage computed tomography venography (CTV) can be expected to increase imaging contrast and decrease radiation exposure by using iterative reconstruction (IR). This study evaluated the diagnostic ability of low tube voltage CTV with IR for deep vein thrombosis (DVT), compared to ultrasonography (US).Methods and Results:Two experienced radiologists retrospectively reevaluated the CTV data of 55 of 318 consecutive patients suspected of having DVT or pulmonary embolism between December 2015 and April 2017. The 55 patients had undergone both low tube voltage CTV and US (within 1 day before or after CTV). The lower extremity veins were divided into 10 segments. The DVT forms were categorized into 3 types: complete, concentric, and eccentric. We analyzed the 534 overall segments (16 segments excluded in US) measured using both CTV and US. The sensitivity-specificity was overall 73.3-90.0%, for femoropopliteal, it was 90.0-93.2%, and for the calf, it was 71.1-87.2%. The diagnostic accuracy between the 'eccentric only' and 'others' groups focusing on DVT forms was compared, and significant differences were revealed, especially in the muscular vein. CONCLUSIONS: The DVT diagnostic ability above the knee was comparable between low tube voltage CTV with IR and conventional CTV, and the radiation dose was reduced. It was suggested that eccentric DVT measured by CTV tend to be a false-positive, especially in the calf muscular vein.

Successful repeated uterine artery embolization in postpartum hemorrhage with disseminated intravascular coagulation: a case report and literature review.

BACKGROUND: Postpartum hemorrhage (PPH) is a potentially fatal condition requiring urgent and appropriate intervention. Uterine artery embolization (UAE) has a high hemostatic capacity for PPH, but it may fail. Disseminated intravascular coagulation (DIC) has been reported as a risk factor associated with the failure of UAE. CASE PRESENTATION: A 37-year-old primigravida with dichorionic diamniotic twins and placenta previa underwent cesarean section. The blood loss during surgery was 4950 mL. Hemostasis was achieved using an intrauterine balloon tamponade device. However, she lost a further 2400 mL of blood 5 h after surgery. We embolized both uterine arteries using gelatin sponges and confirmed hemostasis. She was suffering from DIC and received ample blood transfusions. However, a further 1300 mL of blood was lost 18 h after surgery and we performed repeated UAE, with complete recanalization of the uterine arteries on both sides and re-embolization with gelatin sponges. Her DIC was treated successfully by blood transfusions at this time, and she showed no further bleeding after the repeated UAE. CONCLUSIONS: DIC is a risk factor for the failure of UAE. Repeated UAE may be effective after sufficient improvement of the hematological status in patients with PPH and DIC.

A Simplified Cluster Analysis of Electron Track Structure for Estimating Complex DNA Damage Yields.

Complex DNA damage, defined as at least two vicinal lesions within 10-20 base pairs (bp), induced after exposure to ionizing radiation, is recognized as fatal damage to human tissue. Due to the difficulty of directly measuring the aggregation of DNA damage at the nano-meter scale, many cluster analyses of inelastic interactions based on Monte Carlo simulation for radiation track structure in liquid water have been conducted to evaluate DNA damage. Meanwhile, the experimental technique to detect complex DNA damage has evolved in recent decades, so both approaches with simulation and experiment get used for investigating complex DNA damage. During this study, we propose a simplified cluster analysis of ionization and electronic excitation events within 10 bp based on track structure for estimating complex DNA damage yields for electron and X-ray irradiations. We then compare the computational results with the experimental complex DNA damage coupled with base damage (BD) measured by enzymatic cleavage and atomic force microscopy (AFM). The computational results agree well with experimental fractions of complex damage yields, i.e., single and double strand breaks (SSBs, DSBs) and complex BD, when the yield ratio of BD/SSB is assumed to be 1.3. Considering the comparison of complex DSB yields, i.e., DSB + BD and DSB + 2BD, between simulation and experimental data, we find that the aggregation degree of the events along electron tracks reflects the complexity of induced DNA damage, showing 43.5% of DSB induced after 70 kVp X-ray irradiation can be classified as a complex form coupled with BD. The present simulation enables us to quantify the type of complex damage which cannot be measured through in vitro experiments and helps us to interpret the experimental detection efficiency for complex BD measured by AFM. This simple model for estimating complex DNA damage yields contributes to the precise understanding of the DNA damage complexity induced after X-ray and electron irradiations.

Synthesis of Stannole-Containing π-Conjugated Polymers by Post-Element Transformation of Organotitanium Polymer.

The synthesis of stannole-2,5-diyl-containing π-conjugated polymers by the post-element transformation of a regioregular organotitanium polymer is described. For example, a 1,1-diphenylstannole-containing polymer is obtained in 83% yield by the reaction of a regioregular organotitanium polymer, which is prepared from 1,4-bis(2-ethylhexyloxy)-2,5-diethynylbenzene and a low-valent titanium complex with diphenyltin dichloride at -50 °C to ambient temperature. The number-average molecular weight and molecular weight distribution (Mn and Mw /Mn ) of the stannole-containing polymer are estimated as 4800 and 1.8, respectively. The obtained polymer is found to have the extended π-conjugated backbone and relatively low-lying lowest unoccupied molecular orbital (LUMO) energy level (-3.12 eV), which is supported by its UV-vis absorption spectrum and cyclic voltammetric (CV) analysis. In addition, the stannole-containing polymer is found to be applicable to a chemosensor for fluoride anion where the color and photoluminescence intensity of the polymer solution exhibits a distinct change in the presence of a fluoride anion.

Relationship between the morphology of the foveal avascular zone and the degree of aniseikonia before and after vitrectomy in patients with unilateral epiretinal membrane.

PURPOSE: Persistent metamorphopsia, particularly aniseikonia, is a troublesome problem which may occur after epiretinal membrane (ERM) surgery. To clarify if the preoperative foveal avascular zone (FAZ) morphology can be used as a predictor of postoperative residual aniseikonia, the morphological changes in the FAZ and the degree of aniseikonia between before and 12 months after vitrectomy for epiretinal membrane (ERM) were measured and analyzed. METHODS: Thirty patients, each with a unilateral idiopathic ERM, who underwent treatment between September 2016 and March 2017 were enrolled for this prospective case series study. Best-corrected visual acuity (BCVA), the degree of aniseikonia, central foveal thickness (CFT), FAZ area (FAZa), perimeter (FAZp), and circularity in ERM eyes were examined before and 1, 3, 6 and 12 months after surgery. The fellow eye without an ERM was also examined and used as the control. The interocular ratios of the CFT, FAZa, and FAZp in ERM eyes with those in control eyes were also calculated. Multiple regression analysis was performed on preoperative parameters that were found to be significantly correlated with the 12-month aniseikonia in univariate analyses. RESULTS: The BCVA in the ERM eyes was significantly improved at 1 month after surgery (P < .0001) The degree of aniseikonia was significantly reduced only after 12 months (P = .004). The CFT had decreased significantly by 3 months after the surgery and continued decreasing thereafter (P < .0001). Both FAZa and FAZp were significantly smaller in the ERM eyes than in the control eyes throughout the study period (P < .0001 and P < .0001, respectively), with no change in either parameter over the study period. Correlation analyses revealed that the degree of aniseikonia was significantly correlated with pre- and postoperative CFT, CFT ratio, FAZa, FAZa ratio, FAZp, and FAZp ratio. Within preoperative OCT parameters, FAZa ratio remained significant after multiple regression analysis was performed (P < .0001). CONCLUSIONS: Aniseikonia changed little over the long term following ERM surgery. Preoperative FAZ area ratio was identified as a significant predictor of postoperative aniseikonia.

Anatomical and functional changes in paravascular abnormalities after epiretinal membrane removal.

PURPOSE: To investigate the anatomical and functional changes in areas containing paravascular abnormalities (PVA) in eyes with epiretinal membrane (ERM) after surgery. METHODS: Twenty-eight eyes with concurrent idiopathic ERM and PVA were enrolled in this prospective study. Best-corrected visual acuity (BCVA), central macular thickness (CMT), and areas of PVA in the superficial and deep capillary levels detected on en face optical coherence tomography were measured preoperatively and 1, 3, and 6 months postoperatively. Retinal sensitivity in selected PVA lesions was evaluated by microperimetry preoperatively and 1 and 6 months postoperatively. RESULTS: The areas of PVA at the superficial capillary level before and 1, 3, and 6 months after surgery measured 1.65 ± 1.27, 0.44 ± 0.62, 0.40 ± 0.64, and 0.38 ± 0.62 mm2, respectively, while those at the deep capillary level measured 0.27 ± 0.57, 0.10 ± 0.26, 0.09 ± 0.29, and 0.05 ± 0.15 mm2, respectively. The areas of PVA in the superficial and deep capillary levels were significantly smaller postoperatively (all p < 0.001 at the superficial capillary level and p = 0.010 at the deep capillary level). Average retinal sensitivity values in the PVA lesions before and 1 and 6 months after surgery were 11.2 ± 3.5, 12.9 ± 3.2, and 13.2 ± 2.7 dB, respectively; the values at postoperative months 1 and 6 were significantly improved (p = 0.045 and p < 0.001, respectively). BCVA and CMT were significantly improved postoperatively. CONCLUSION: PVA not only improves anatomically but also functionally after ERM surgery. Vitrectomy can improve not only central vision but also retinal sensitivity in areas of PVA.

Surgical Factors Affecting Changes in Ocular Surface Dynamics in the Early Postoperative Period After 25-Gauge Vitrectomy.

OBJECTIVES: Because vitrectomy-associated postoperative ocular surface changes are not well known, we evaluated such changes before and after vitrectomy in eyes with posterior segment diseases and investigated their associations with patients' characteristics and surgical procedures. METHODS: Thirty-five eyes of 32 consecutive patients (16 women; average age 66.6±11.1 years) were included in this prospective, noncomparative case series from tertiary care university hospital. Contact lens wearers and patients with history of ocular surgery or regular use of topical eyedrops were excluded. Patients had undergone primary 25-gauge vitrectomy at Osaka University Hospital in Japan between July and December 2016. Tear break-up time (TBUT), corneal and conjunctival fluorescein staining score (FSS), and tear meniscus height (TMH) were evaluated before, 1 week after, and 1 month after vitrectomy. RESULTS: Conjunctival FSS and TMH were significantly higher at 1 week after vitrectomy than preoperatively. However, they decreased significantly 1 month after. Changes in TBUT and corneal FSS showed a similar course at 1 week, but this was not statistically significant. Multiple linear regression analysis showed no significant correlation between significantly increased ocular parameters and patients' characteristics. By contrast, surgical time and combined cataract surgery significantly contributed to increased and decreased conjunctival FSS, respectively (P=0.011 and 0.033, respectively). Sclerotomy site suturing significantly contributed to increased TMH (P=0.025). CONCLUSIONS: We showed associations between ocular surface changes and specific surgical procedures. Caution should be exercised to minimize the effect of surgical procedures on the ocular surface during vitrectomy.

RETINAL MICROVASCULATURE AND VISUAL ACUITY AFTER INTRAVITREAL AFLIBERCEPT IN EYES WITH CENTRAL RETINAL VEIN OCCLUSION: An Optical Coherence Tomography Angiography Study.

PURPOSE: To investigate vascular perfusion and foveal avascular zone area in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) after intravitreal aflibercept therapy in central retinal vein occlusion eyes and their association with best-corrected visual acuity. METHODS: Thirty-five subjects with central retinal vein occlusion and macular edema were evaluated. After macular edema resolution following intravitreal aflibercept, subjects underwent optical coherence tomography angiography to measure SCP and DCP perfusion and the foveal avascular zone within a 3 × 3-mm area. Correlations between best-corrected visual acuity and optical coherence tomography angiography measurements were examined. RESULTS: After intravitreal aflibercept therapy, mean retinal vascular area was 3.41 ± 0.74 mm in the SCP and 3.25 ± 0.91 mm in the DCP. Foveal avascular zone area was 1.03 ± 1.04 mm in the SCP and 1.78 ± 1.73 mm in the DCP. Improved best-corrected visual acuity was significantly associated with better SCP and DCP perfusion (both P < 0.001) and with smaller SCP and DCP foveal avascular zone areas (both P < 0.001). Additionally, SCP and DCP perfusion were negatively correlated with macular edema before treatment (P < 0.05) and ischemia (determined via pretreatment fluorescein angiography, P < 0.05), and positively correlated with photoreceptor integrity (P < 0.001). CONCLUSION: Patients with better retinal perfusion and less retinal ischemia are associated with better visual outcomes after aflibercept in eyes with central retinal vein occlusion.

Errata: Internal doses from radionuclides and their health effects following the Fukushima accident (J. Radiol. Prot. 2018 38 1253-68).

This article presents errata on a published article.

Internal doses from radionuclides and their health effects following the Fukushima accident.

This paper presents an overview of current internal dose estimates from the Fukushima accident, potential population specific uncertainties in these estimates are investigated, along with the relative effects of internal and external exposures. Thyroid doses were largely due to 131I, but variations in thyroid weight and fractional uptake and retention times of 131I in the thyroid contribute to uncertainties in thyroid dose estimates. Lower values for these parameters in the Japanese population, as compared to international reference assumptions, would lead to underestimation of doses on the basis of reference thyroid weights and overestimation of doses using reference thyroid uptake and retention times. Any overall bias in thyroidal doses due to population specific factors is the net result of the balance between these effects. Internal doses to other organs are largely due to 134Cs and 137Cs and their whole body distribution, population specific differences in these dose estimates are driven by average body mass, due to the inverse relationship between this and retention times. Potential differences in dose estimates and any inferred risks, due to local population specific factors, may be less than a factor of two for children and male adults, but the potential difference may be slightly underestimated for female adults. Recent micro-dosimetric studies have confirmed the existing perception that risk from internal exposures to 137Cs, 134Cs, and 131I should be nearly equivalent to that from external exposure to gamma rays at the same absorbed dose. Epidemiological studies provide comparisons between external and internal exposures to 131I in children and suggest that effects of internal exposure are similar to those of external exposure. Effective dose has been formulated to harmonise internal and external exposure risks for radiation protection purposes. On the basis of this review, the use of effective dose in this context does not seem to be unreasonable.

Intraoperative B-scan ultrasonography and pars plana vitrectomy for severe open globe injury with hemorrhagic retinal and choroidal detachment.

PURPOSE: Our purpose was to report the initial clinical experience of intraoperative B-scan ultrasonography in combination with 25-gauge pars plana vitrectomy for severe open globe injury with hemorrhagic retinal and choroidal detachment. METHODS: Six eyes of six consecutive patients with severe open globe injury underwent intraoperative B-scan ultrasonography and 25-gauge pars plana vitrectomy at Osaka University Hospital in Japan. The feasibility of intraoperative B-scan ultrasonography, best-corrected visual acuity (BCVA), retinal reattachment, and intraoperative and postoperative complications were evaluated. RESULTS: Five patients presented with a ruptured globe and one patient with double penetration. Preoperative best-corrected visual acuity was no light perception in four eyes and light perception in two eyes. All patients underwent intraoperative B-scan ultrasonography and 25-gauge pars plana vitrectomy within 12 h after open globe injury. Intraoperative B-scan ultrasonography was feasible in all cases and was useful for diagnosing choroidal hemorrhage (four eyes), massive subretinal hemorrhage (two eyes), and retinal detachment (five eyes). In addition, serial real-time B-scan imaging facilitated successful evacuation of the choroidal hemorrhage and massive subretinal hemorrhage by external drainage, resulting in opening of the vitreous space to allow subsequent pars plana vitrectomy without entry site-related complications. After surgery, all patients had successful retinal attachment, and there was no loss of light perception. CONCLUSION: Intraoperative B-scan ultrasonography is technically feasible and may potentially improve the safety and efficacy of severe open globe injury repair.

Retinal thickness in parafoveal subfields and visual acuity after vitrectomy for macula-off rhegmatogenous retinal detachment repair.

PURPOSE: To investigate retinal thickness in the central and parafoveal subfields, including segmented analysis of the inner and outer retinal layers, after vitrectomy for macula-off rhegmatogenous retinal detachment (RRD) repair. METHODS: Twenty-four eyes of 24 patients who underwent primary vitrectomy for macula-off RRD repair were enrolled in this study. Spectral-domain optical coherence tomography examination and best-corrected visual acuity (BCVA) measurements were performed at 1, 3, and 6 months after vitrectomy. RESULTS: At 1, 3, and 6 months after vitrectomy, retinal thickness in the temporal parafoveal subfield was more significantly (P = 0.004, 0.001, and 0.003, respectively) correlated with BCVA than the central subfield (P = 0.014, 0.001, and 0.022, respectively). Segmented analysis showed significant correlations between the retinal thickness of both the outer layer (P = 0.018, 0.030, and 0.018, respectively) and the inner layer (P = 0.003, 0.002, and 0.001, respectively) in the temporal parafoveal subfield and BCVA at every time point after vitrectomy. CONCLUSIONS: These results suggest that retinal thickness in the temporal parafoveal subfield may most closely reflect postoperative BCVA after macula-off RRD repair.

Characteristics of cases with postoperative vitreous hemorrhage after 25-gauge vitrectomy for repair of proliferative diabetic retinopathy.

PURPOSE: The purpose of this study was to compare ocular and systemic parameters between proliferative diabetic retinopathy (PDR) cases with postoperative vitreous hemorrhage (PVH) and those without PVH after 25-gauge vitrectomy, and to investigate the predictors of PVH. METHODS: The medical records of 106 eyes of 78 consecutive patients who underwent primary 25-gauge vitrectomy were reviewed. RESULTS: The incidences of early and late PVH were found to be 18.9 % (20/106 eyes) and 17.9 % (19/106 eyes) respectively. On multiple logistic regression analysis, intraoperative bleeding from new vessels on the disc was identified as the most important factor, with the greatest odds ratio, for the development of early PVH (odds ratio = 3.395, P = 0.134), while the HbA1c level was identified as the most important significant factor, with the greatest odds ratio, for the development of late PVH (odds ratio = 1.403, P = 0.014). CONCLUSIONS: Early PVH tends to occur in severe PDR cases, while late PVH tends to occur in cases with poor diabetic control.

Feasibility of a polyethylene glycol-derived polymer as retinal patch to seal retinal breaks during vitrectomy for rhegmatogenous retinal detachment: a prospective, in vivo pilot study in a porcine model.

BACKGROUND: This is a pilot study to test a polyethylene glycol-derived polymer used as a retinal patch to seal retinal breaks during pars plana vitrectomy in the treatment of rhegmatogenous retinal detachment in a porcine model. METHODS: Sixteen eyes from eight pigs were assigned to two study groups (12 eyes) and one control group (four eyes). In all study groups, the polymer was used in vivo, during pars plana vitrectomy, to seal the break of a surgically induced rhegmatogenous retinal detachment. Eyes in study groups were filled with balanced saline solution at the end of the surgery. In the control group, the polymer was not used and the eyes underwent standard rhegmatogenous retinal detachment repair with pars plana vitrectomy. All eyes underwent fundus examination at day 3, week 1 and week 2 after surgery. All eyes from all groups were enucleated and processed for qualitative histological evaluation. RESULTS: Intraoperatively, the polymer showed good adherence and compliance to the retina. At week 1, retina was attached in all cases. The polymer was visible with indirect ophthalmoscopy up to week 1. At week 2, the polymer was no longer visible. Histologically, a mild histiocytic reaction was noticed in the retinas of four out of 12 study eyes (33.3%). In the control eyes, non-specific inflammatory signs of retinal inflammation were reported in two out of four eyes (50%). CONCLUSIONS: This study provides initial data to support the use of this polymer as a promising alternative to standard endo-tamponade agents. Its safety and biocompatibility need to be further assessed.