Invivo generated autologous plasmin enzyme assisted vitrectomy, partial circumferential-oral retinotomy, silicone oil injection in patients with chronic retinal detachment without posterior vitreous detachment.

PURPOSE: To report the results of invivo generated autologous plasmin enzyme(IVAP) assisted vitrectomy, partial circumferential-oral retinotomy and silicone oil injection for surgical treatment of patients with chronic retinal detachment without posterior vitreous detachment(PVD). METHODS: Study was performed in retrospective, comparative manner. A total of 16 consecutive eyes with chronic retinal detachment who had intravitreal injection of 50 µgr of t-PA and 0.1 ml of autologous whole blood, 3 days before surgery, underwent lens extraction with phacoemulsification, IVAP assisted vitrectomy, partial circumferential-oral retinotomy, and silicone oil injection(Study Group) were compared to a similar group of 15 eyes who had undergone vitrectomy, with or without lens extraction and silicone oil injection(Control Group) for the treatment of chronic retinal detachment. Primary outcome measures were initial retinal reattachment and number of operations at postoperative 6 months. RESULTS: Mean age of 16 patients of whom 7 were female, was 39.31 ± 17.76 years in study group and 15 patients of whom 4 were female, was 35.40 ± 11.92 years (p = 0.607). Mean follow-up time was 10.68 ± 7.15 months in study group and 29.13 ± 18.83 months in control group (p = 0.001). Initial retinal reattachment was achieved in 87.50% (14 out of 16 patients) in the study group, whereas it was 46.66% (7 out of 15 patients) in the control group (p = 0.017). The mean number of operations for reattachment in the study group was 1.12 ± 0.34, whereas it was 1.46 ± 0.51 in the control group (p = 0.039) at postoperative 6 months While the preoperative LogMAR visual acuity was 1.25 ± 0.64, it was 0.53 ± 0.37 at postoperative 6 months in study group (p = 0.001). Conversely, in the control group, the preoperative LogMAR visual acuity was 1.22 ± 0.33, it was 1.20 ± 0.89 at postoperative 6 months (p = 0.780). At postoperative 6 months,, epiretinal membrane developed in 2 eyes of the study group, 1 eye in the control group, and phthisis bulbi occurred in 1 eye of control group. CONCLUSION: IVAP assisted vitrectomy, partial circumferential-oral retinotomy and silicone oil injection is effective and safe for the surgical treatment of chronic retinal detachment without PVD.

Preoperative co-application of bevacizumab and tissue plasminogen activator in vitrectomy for proliferative diabetic retinopathy.

PURPOSE: To investigate the clinical benefits of the co-application of bevacizumab and tissue plasminogen activator as adjuncts in the surgical treatment of proliferative diabetic retinopathy. METHODS: Patients who underwent vitrectomy for proliferative dia-betic retinopathy complications were preoperatively given in-travitreal injection with either bevacizumab and tissue plasminogen activator (Group 1) or bevacizumab alone (Group 2). Primary outcomes were surgery time and number of intraoperative iatrogenic retinal breaks. Secondary outcomes included changes in the best-corrected visual acuity and postoperative complications at 3 months postoperatively. RESULTS: The mean surgery time in Group 1 (52.95 ± 5.90 min) was significantly shorter than that in Group 2 (79.61 ± 12.63 min) (p<0.001). The mean number of iatrogenic retinal breaks was 0.50 ± 0.59 (0-2) in Group 1 and 2.00 ± 0.83 (0-3) in Group 2 (p<0.001). The best-corrected visual acuity significantly improved in both groups (p<0.001). One eye in each group developed retinal detachment. CONCLUSION: Preoperative co-application of bevacizumab and tissue plasminogen activator as adjuncts in the surgical treatment of proliferative diabetic retinopathy shortens the surgery time and reduces the number of intraoperative iatrogenic retinal breaks.

Foveal light exposure is increased at the time of removal of silicone oil with the potential for phototoxicity.

BACKGROUND: There is sudden and dramatic visual function deterioration in 1-10 % of eyes filled with silicone oil at the time of removal of silicon oil. Transmission of high-energy blue light is increased in eyes filled with silicone oil. We sought to identify if increased foveal light exposure is a potential factor in the pathophysiology of the visual loss at the time of removal of silicone oil. METHODS: A graphic ray tracing computer program and laboratory models were used to determine the effect of the intraocular silicone oil bubble size on the foveal illuminance at the time of removal of silicone oil under direct microscope light. The graphic ray tracing computer program revealed a range of optical vignetting effects created by different sizes of silicone oil bubble within the vitreous cavity giving rise to an uneven macular illumination. The laboratory model was used to quantify the variation of illuminance at the foveal region with different sizes of silicone oil bubble with in the vitreous cavity at the time of removal of silicon oil under direct microscope light. To substantiate the hypothesis of the light toxicity during removal of silicone oil, The outcome of oil removal procedures performed under direct microscope illumination in compared to those performed under blocked illumination. RESULTS: The computer program showed that the optical vignetting effect at the macula was dependent on the size of the intraocular silicone oil bubble. The laboratory eye model showed that the foveal illuminance followed a bell-shaped curve with 70 % greater illuminance demonstrated at with 50-60 % silicone oil fill. The clinical data identified five eyes with unexplained vision loss out of 114 eyes that had the procedure performed under direct microscope illumination compared to none out of 78 eyes that had the procedure under blocked illumination. CONCLUSIONS: Foveal light exposure, and therefore the potential for phototoxicity, is transiently increased at the time of removal of silicone oil. This is due to uneven macular illumination resulting from the optical vignetting effect of different silicone oil bubble sizes. The increase in foveal light exposure may be significant when the procedure is performed under bright operating microscope light on already stressed photoreceptors of an eye filled with silicon oil. We advocate the use of precautions, such as central shadow filter on the operating microscope light source to reduce foveal light exposure and the risk of phototoxicity at the time of removal of silicone oil. The graphic ray tracing computer program used in this study shows promise in eye modeling for future studies.

In vivo generated autologous plasmin assisted vitrectomy in young patients.

BACKGROUND: Autologous plasmin enzyme facilitates the induction of posterior vitreous detachment(PVD) during vitrectomy in young patients. We proposed the concept of in-vivo generated plasmin which is based on the injection of tissue plasminogen activator(t-PA) and autologous whole blood(AWB) into the vitreous cavity. The purpose of this pilot study is to report the efficacy of preoperative simultaneous intravitreal injection of(t-PA) and autologous whole blood in facilitating the intraoperative induction of PVD in young patients with various vitreoretinal pathologies. METHODS: Seventeen eyes of 16 young patients with various vitreoretinal pathologies requiring vitrectomy, who received simultaneous intravitreal injection of 0.1 ml of AWB and 25 µg of t-PA, 3 days prior to surgery were retrospectively reviewed. Outcome measures were the number of attempts required to achieve successful intraoperative separation of the posterior hyaloid; the postoperative visual acuity; and intraoperative and postoperative complications. RESULTS: The mean age of the patients was 23.87 ± 10.09 years, ranging from 10 to 39 years. Eight of 16 patients were men. The mean follow-up time was 19.35 ± 5.04 months, ranging from 12 to 26 months. Surgical indications for vitrectomy were chronic retinal detachment (n = 7), traumatic retinal detachment without proliferative vitreoretinopathy(n = 3), traumatic macular hole(n = 1), secondary vasoproliferative tumor(n = 4) and optic pit maculopathy(n = 2). Patients with retinal detachment complicated with PVR and those who were older than 40 years of age were excluded from the study. Separation of the Weiss ring from the optic nerve head was achieved intraoperatively in all cases, with a mean number of 2.86 ± 1.4 attempts. While the mean preoperative LogMAR visual acuity was 1.38 ± 0.59, ranging from 2.40 to 0.50, it was a mean of 0.51 ± 0.29, ranging from 1.00 to 0.10 at final postoperative exam(p < 0.001; paired samples t-test). No preoperative or intraoperative complications were noted. CONCLUSION: Preoperative simultaneous intravitreal injection of 25 µg t-PA with 0.1 ml of AWB facilitates the intraoperative induction of posterior vitreous detachment in young patients.

The Influence of Slit Lamp Shield Size and Design in Reducing Aerosol Transmission.

Purpose: Previous studies have highlighted the effectiveness of slit lamp shields in reducing aerosol spread. Our study investigated the optimal size and design for such shields. Methods: Two sets of shields were made; each set included five cardboards of the following dimensions: 1 (44 × 52 cm), 2 (44 × 44 cm), 3 (22 × 52 cm), 4 (22 × 33.5 cm), and 5 (44 × 22.5 cm). Cardboards in set 1 were kept flat whereas those in set 2 were curved using plastic frames. Aerosol was generated at the patient's position using a water spray bottle, and aerosol levels were measured at the face position of the examiner and on the slit lamp table using two GP2Y1014AU0F sensors. The measurements were recorded in particles/0.01f3 and analyzed using a Mann Whitney U test. Results: Mean background indoor aerosol was 559. After aerosol generation, the level increased to a mean of 571 in the absence of any kind of shield but to a mean of 567 when shields were in place (P < 0.05). Flat shield 1 provided the best protection against inhaled aerosol. Flat shield 2, despite its shorter height compared to shield 1, provided the best protection against precipitated aerosol on the table. Curving shield 5 significantly improved its protective properties against both inhaled and precipitated aerosol while keeping the short height that allowed better access during examinations. Conclusions: Shields reduced aerosol spread with curved shields being more effective while creating fewer physical restrictions. GP2Y1014AU0F particle sensors are effective tools for quantifying aerosol spread. Translational Relevance: An understanding of optimal slit lamp shield design will provide protection for examiners while facilitating effective examination.

The Surgeon's Role in Inducing and Controlling Motion Errors During Intraocular Membrane Peeling Procedures

Objectives: To understand the surgeon's role in inducing and correcting movement inaccuracies during intraocular membrane peeling procedures. Materials and Methods: Optical sensors were used to record movement errors during actuation at the distal tip of 23-gauge pneumatic forceps both when the handle was handheld and when fixed with no human contact. Movements were also recorded at the proximal part of the forceps shaft (near the sclerotomy site) and compared to movement recorded at the distal end. The root mean square (RMS) and range values of the signals obtained from the sensors were calculated before and after applying high (7-13 Hz) and low (<5 Hz) frequency filters. Results: Comparison of RMS and range values of movement errors at the distal end of the forceps during actuation when the forceps handle was fixed and handheld showed that without human contact, these values were significantly lower in the X axis at all frequencies and in the Z axis at high frequencies compared to handheld (p<0.05), while there were no significant differences in the Y axis. Comparison of values from the distal and proximal ends of the forceps showed that when the forceps were fixed, RMS and range values were significantly higher for movement errors at the distal end compared to the proximal end at all frequencies (p<0.05). There was significant positive correlation between the extent of actuation and the RMS and range values for high-frequency movement errors but not low-frequency errors in all three axes with the fixed pneumatic handle (r=0.21-0.51, p<0.05). Conclusion: Surgeon- and non-surgeon-related errors are apparent in all axes, but skilled surgeons correct these errors through visual feedback, resulting in better correction in the visible planes. Sclerotomy sites provide a pivoting and stabilizing point for the shaft of the forceps and it is likely that skilled surgeons make use of the sclerotomy point to dampen motion errors, a skill worth teaching to beginners.

Experimental Laboratory Modeling of Choroidal Vasculature: A Study of the Dynamics of Intraoperative Choroidal Hemorrhage during Pars Plana Vitrectomy

Objectives: Choroidal hemorrhages (CH) result from rupture of choroidal vessels leading to extravasation of blood into the suprachoroidal space. In this study, we aimed to understand the hemodynamics of CH by developing a purpose-built scale model of the choroidal vasculature and calculating stress levels in the model under different conditions. Materials and Methods: We modeled the choroidal vasculature using a rubber tube 10 cm in length and 1 cm in diameter that was wrapped with conductive thread to enable the measurement of stress at the walls of the tube. Stress levels across the tube were continuously measured under different systemic intravascular blood pressure levels (IVP), intraocular pressure (IOP) levels, and distortion. Results: Stress values across the choroidal vessel model correlated negatively with IOP and positively with IVP and distortion. All correlations were statistically significant (p<0.05) and were stronger when the model was filled with expansile tamponade compared to non-expansile tamponades. Distortion showed the strongest correlation in terms of increasing stress across the model, while IVP showed stronger correlation compared to IOP. Raising IOP to counteract the stress in the model was effective when the stress in the model was secondary to increased IVP, but this approach was not effective when the stress in the model was caused by distortion. Conclusion: Excessive distortion of the globe during surgical maneuvers could be the primary reason for the rarely observed intraoperative CH. Non-expansile ocular tamponade provides better support for the vascular bed against CH and should be the recommended choice of tamponade in patients with existing CH. Increasing IOP excessively is of limited effect in preventing CH in vessels that are under stress as a result of distorting surgical maneuvers.

Standardized Classification of Mechanical Ocular Injuries: Efficacy and Shortfalls.

OBJECTIVES: The aim of this study was to examine the efficacy and the shortfalls of the Birmingham Eye Trauma Terminology classification system for ocular trauma in predicting the visual outcome. METHODS: The records of 256 eyes of 246 patients with a diagnosis of mechanical ocular trauma admitted to the Osman Gazi University Hospital ophthalmology department between 1995 and 2000 were retrospectively reviewed. The zone, type, grade, and pupil status of the injuries were determined according to the Birmingham classification system. Injuries with a good prognosis were defined as injuries that resulted in vision of equal to or better than counting fingers at 1 meter. Fischer's exact test was used to determine the statistical significance of relationships between the final visual acuity and the initial clinical findings. RESULTS: Open eye injuries restricted to zone I, those with no afferent pupillary defect, and those graded as 3 or better or classed as type B were significantly associated with a better visual outcome (p<0.05). Open eye injuries that extended to zone III, had an afferent pupillary defect, or were graded as 4 or worse were significantly associated with a poorer visual outcome (p<0.05). Closed eye injuries classified as type B or grade 4 were significantly associated with a poor visual outcome (p<0.05). CONCLUSION: The Birmingham classification system for mechanical ocular trauma offers a standardized method for both open and closed eye injuries, however, adding subclasses to type C (injuries with foreign body involvement) could enhance the classification method and help to understand the influence of foreign body properties and sizes on the outcome.

Performance of a North American field population and a laboratory colony of the potato tuberworm, Phthorimaea operculella, on foliage of resistant and susceptible potato clones.

Foliar resistance of two potato clones was tested against a Columbia Basin field population (CBFP) and a Colorado laboratory colony (COLC) of the potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae). The first clone was a cross of a cultivated potato, Solanum tuberosum L. (Solanales: Solanaceae), and a wild potato, Solanum berthaultii Hawkes (Q 174-2); the second clone was cv. Allegany, S. tuberosum L.. In no-choice assays, defoliation by P. operculella larvae of COLC and CBFP did not differ on Allegany and Q174-2. Larval weight and production of COLC and CBFP colonies were similarly reduced on Q174-2 compared to cv. Allegany, although larval weights and production of the CBFP population were slightly less affected by the host. Larval production by the COLC on Allegany was greater than that on Q174-2, while that of the CBFP on Allegany and Q174-2 did not differ. However, production of P. operculella larvae by the CBFP on Q174-2 during no-choice assays was greater than that in choice tests, indicating reduced host preference. Most of the larvae recovered from either host were fourth instars, followed by third instars. Although the levels of resistance expressed by Q174-2 potato clone to the two P. operculella populations differed in magnitude, nearly all of P. operculella performance criteria measured in this study were adversely affected by Q174-2 foliage compared to the commercial potato cultivar, cv. Allegany.

A method for subsampling terrestrial invertebrate samples in the laboratory: estimating abundance and taxa richness.

Significant progress has been made in developing subsampling techniques to process large samples of aquatic invertebrates. However, limited information is available regarding subsampling techniques for terrestrial invertebrate samples. Therefore a novel subsampling procedure was evaluated for processing samples of terrestrial invertebrates collected using two common field techniques: pitfall and pan traps. A three-phase sorting protocol was developed for estimating abundance and taxa richness of invertebrates. First, large invertebrates and plant material were removed from the sample using a sieve with a 4 mm mesh size. Second, the sample was poured into a specially designed, gridded sampling tray, and 16 cells, comprising 25% of the sampling tray, were randomly subsampled and processed. Third, the remainder of the sample was scanned for 4-7 min to record rare taxa missed in the second phase. To compare estimated abundance and taxa richness with the true values of these variables for the samples, the remainder of each sample was processed completely. The results were analyzed relative to three sample size categories: samples with less than 250 invertebrates (low abundance samples), samples with 250-500 invertebrates (moderate abundance samples), and samples with more than 500 invertebrates (high abundance samples). The number of invertebrates estimated after subsampling eight or more cells was highly precise for all sizes and types of samples. High accuracy for moderate and high abundance samples was achieved after even as few as six subsamples. However, estimates of the number of invertebrates for low abundance samples were less reliable. The subsampling technique also adequately estimated taxa richness; on average, subsampling detected 89% of taxa found in samples. Thus, the subsampling technique provided accurate data on both the abundance and taxa richness of terrestrial invertebrate samples. Importantly, subsampling greatly decreased the time required to process samples, cutting the time per sample by up to 80%. Based on these data, this subsampling technique is recommended to minimize the time and cost of processing moderate to large samples without compromising the integrity of the data and to maximize the information extracted from large terrestrial invertebrate samples. For samples with a relatively low number of invertebrates, complete counting is preferred.

Resistance of potato germplasm to the potato tuberworm (Lepidoptera: Gelechiidae).

The evaluation of potato germplasm for resistance to potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae), is a valuable component of integrated pest management; however, few attempts have been made to identify natural genetic tuber resistance to tuberworm on potato germplasm. The objective of this study was to screen potato germplasm with potential tuberworm resistance for tuber resistance under field and laboratory conditions. Experiments were conducted over a 2-yr period at the Hermiston Agricultural Research and Extension Center, Hermiston, OR. Of 125 germplasm that were tested in 2006, q13 were selected for further screening in 2007. These germplasm were: A0008-1TE, A97066LB, NY123, PA00N10-5, PA99N2, PA99N82, Paciencia, Q174-2, Russet Burbank, Rubi, Ranger Russet, Spunta G2, and T88-4. Tuber resistance of potato germplasm was determined based on the number of mines per tuber and the number of live larvae. Tubers of transgenic clone Spunta G2 were resistant to tuberworm damage. All other germplasm tested in this study, including Russet Burbank and Ranger Russet, were susceptible to tuberworm in the field and laboratory experiments. Incorporation of host plant resistance to tuber penetration by larvae together with appropriate cultural practices including limiting exposure time of tubers in the field may provide the best management option in the future.

Preoperative co-application of bevacizumab and tissue plasminogen activator in vitrectomy for proliferative diabetic retinopathy

ABSTRACT Purpose: To investigate the clinical benefits of the co-application of bevacizumab and tissue plasminogen activator as adjuncts in the surgical treatment of proliferative diabetic retinopathy. Methods: Patients who underwent vitrectomy for proliferative dia-betic retinopathy complications were preoperatively given in-travitreal injection with either bevacizumab and tissue plasminogen activator (Group 1) or bevacizumab alone (Group 2). Primary outcomes were surgery time and number of intraoperative iatrogenic retinal breaks. Secondary outcomes included changes in the best-corrected visual acuity and postoperative complications at 3 months postoperatively. Results: The mean surgery time in Group 1 (52.95 ± 5.90 min) was significantly shorter than that in Group 2 (79.61 ± 12.63 min) (p<0.001). The mean number of iatrogenic retinal breaks was 0.50 ± 0.59 (0-2) in Group 1 and 2.00 ± 0.83 (0-3) in Group 2 (p<0.001). The best-corrected visual acuity significantly improved in both groups (p<0.001). One eye in each group developed retinal detachment. Conclusion: Preoperative co-application of bevacizumab and tissue plasminogen activator as adjuncts in the surgical treatment of proliferative diabetic retinopathy shortens the surgery time and reduces the number of intraoperative iatrogenic retinal breaks.

Unintentional Movements During the Use of Vitreoretinal Forceps.

PURPOSE: Intraocular forceps used in vitreoretinal surgery are actuated by squeezing their handles. We studied the relationship between actuation and any accompanying unintentional movements of the instrument tip, and compared different handle designs and gauges. METHODS: Optical sensors were used to measure involuntary movements of forceps tips while monitoring the extent of actuation. Mean root mean square (RMS) and ranges of signals obtained from sensors were computed before and after applying high (7-13 Hz) and low (<5 Hz) frequency filters. Four handle designs, two gauge sizes, and two users were compared to each other. RESULTS: In the absence of human contact, mean RMS of noise was 6.47 µ and mean range was 21.67 µ. When the forceps were held by the surgeon but kept motionless (no actuation), mean RMS was 58.01 µ and mean range was 156.66 µ. When the forceps were actuated, mean RMS was 214.71 µ and mean range was 566.11 µ. The differences were statistically significant (P < 0.001). The process of actuation by both users was positively correlated with unintentional movements mainly at low frequencies. No statistically significant differences were found between users and between two gauges (23 and 27) at mixed and low frequencies. Pneumatic handles showed less RMS and range values at higher frequencies compared to conventional handle designs. Eliminating human error by fixing pneumatic forceps to the model did not reduce unintentional movements, but eliminated their correlation with actuation. CONCLUSIONS: Actuating forceps was associated directly with increased unintentional low frequency movements at the tip of the forceps when held by hand. TRANSLATIONAL RELEVANCE: A novel system of measuring unintentional forceps tip movement during actuation is described which could be used to guide improved design.

Spatial pattern and sequential sampling of squash bug (Heteroptera: Coreidae) adults in watermelon.

Spatial distribution patterns of adult squash bugs were determined in watermelon, Citrullus lanatus (Thunberg) Matsumura and Nakai, during 2001 and 2002. Results of analysis using Taylor's power law regression model indicated that squash bugs were aggregated in watermelon. Taylor's power law provided a good fit with r2 = 0.94. A fixed precision sequential sampling plan was developed for estimating adult squash bug density at fixed precision levels in watermelon. The plan was tested using a resampling simulation method on nine and 13 independent data sets ranging in density from 0.15 to 2.52 adult squash bugs per plant. Average estimated means obtained in 100 repeated simulation runs were within the 95% CI of the true means for all the data. Average estimated levels of precision were similar to the desired level of precision, particularly when the sampling plan was tested on data having an average mean density of 1.19 adult squash bugs per plant. Also, a sequential sampling for classifying adult squash bug density as below or above economic threshold was developed to assist in the decision-making process. The classification sampling plan is advantageous in that it requires smaller sample sizes to estimate the population status when the population density differs greatly from the action threshold. However, the plan may require excessively large sample sizes when the density is close to the threshold. Therefore, an integrated sequential sampling plan was developed using a combination of a fixed precision and classification sequential sampling plans. The integration of sampling plans can help reduce sampling requirements.

Tritrophic interaction of parasitoid Lysiphlebus testaceipes (Hymenoptera: Aphidiidae), greenbug, Schizaphis graminum (Homoptera: Aphididae), and greenbug-resistant sorghum hybrids.

Interactions of the parasitoid Lysiphlebus testaceipes (Cresson) and the greenbug, Schizaphis graminum (Rondani), on greenbug-resistant 'Cargill 607E' (antibiosis), 'Cargill 797' (primarily tolerance), and -susceptible 'Golden Harvest 510B' sorghum, Sorghum bicolor (L.) Moench, were tested using three levels of biotype I greenbug infestation. The parasitoid infestation rate was 0.5 female and 1.0 male L. testaceipes per plant. For all three greenbug infestation levels, the parasitoid brought the greenbug under control (i.e., prevented the greenbugs from killing the plants) on both resistant hybrids, but it did not prevent heavy leaf damage at the higher greenbug infestation rates. At the low greenbug infestation rate (50 greenbugs per resistant plant when parasitoids were introduced), greenbugs damaged 5 and 18% of the total leaf area on 'Cargill 797' and 'Cargill 607E', respectively, before greenbugs were eliminated. Leaf damage was higher for the intermediate infestation study (120 greenbugs per plant), 21% and 30% leaf area were damaged on the resistant sorghum hybrids 'Cargill 797' and 'Cargill 607E', respectively. At the high greenbug infestation rate (300 greenbugs per plant), heavy damage occurred: 61% on 'Cargill 607E' and 75% on 'Cargill 797'. The parasitoids did not control greenbugs on the susceptible sorghum hybrid 'Golden Harvest 510B'. L. testaceipes provided comparable control on both greenbug-resistant hybrids. This study supports previous studies indicating that L. testaceipes is effective in controlling greenbugs on sorghum with antibiosis resistance to greenbugs. Furthermore, new information is provided indicating that L. testaceipes is also effective in controlling greenbugs on a greenbug-tolerant hybrid.

Comparison of management strategies for squash bugs (Hemiptera: Coreidae) in watermelon.

Two watermelon pest management practices, a squash trap crop and a standard recommendation using soil-applied carbofuran, were compared using large-scale field plots to assess trap crop suitability as a replacement for the standard in 2000, 2001, and 2002. In both systems, foliar insecticide applications were used to control squash bugs when populations exceeded threshold levels. During 2001 and 2002, a treatment of untreated watermelon was used. Early season adult insects, from seedling to fruit set, are most critical for watermelon. Significantly fewer early adult bugs were found on watermelon in the trap crop than in the standard recommended practice in 1 of 3 yr. In both years, significantly fewer adult squash bugs were found in watermelon in the trap crop than in untreated fields. The standard recommended practice significantly reduced adult squash bugs in watermelon compared with the untreated in 1 of 2 yr. There was no significant correlation of watermelon yield and squash bug density, indicating that squash bug densities were too low to impact yield. Although squash bugs were reduced significantly by the trap crop, marketable watermelon yields were lower in the squash trap crop than in untreated watermelon, suggesting that pest management treatments may interfere with crop productivity factors other than squash bug colonization. Results suggest that mid-season production squash bug should be managed by monitoring populations and using insecticides as needed rather than using at-plant treatment. Further research is needed to compare treatments during early-season production.

Dynamics of epiretinal membrane removal off the retinal surface: a computer simulation project.

AIM: To use a computer simulation to discern the safest angle at which to peel epiretinal membranes. METHODS: We used ANSYS V.14.1 software to analyse the dynamics involved in membrane removal off the retinal surface. The geometrical values were taken from optical coherence tomography of 30 eyes with epiretinal membranes. A range of Young's modulus values of 0.03, 0.01 and 0.09 MPa were assigned to the epiretinal membrane and to the retina separately. The ratio of maximum shear stress (MSS) recorded at the attachment pegs over that recorded at the membrane (P/E ratio) was determined at nine displacement angles (DA). RESULTS: Mean MSS values recorded at the attachment pegs, epiretinal membrane and retina were significantly different at 0.8668, 0.6091 and 0.0017 Pa consecutively (p<0.05). There was a significant negative linear correlation between DA and MSS recorded at the epiretinal membrane when the Young's modulus for the epiretinal membrane was higher than or equal to that for the attachment pegs and the retina. Nevertheless, there was a significant positive linear correlation between DA and P/E ratio when the Young's modulus for the epiretinal membrane was equal to or lower than that for the attachment pegs and the retina. CONCLUSIONS: Attachment pegs appear to be the most likely part to fail (tear) during removal procedures. Changing the direction at which the edge of the membrane is pulled can relocate the MSS within in the tissue complex. Safer and effective removal could be achieved by pulling epiretinal membranes onto themselves at 165° DA.

Macular displacement following rhegmatogenous retinal detachment repair.

AIMS: To investigate the incidence of macula displacement and symptoms of distortion following rhegmatogenous retinal detachment (RRD) repair, quantify the displacement where seen and further characterise the nature of the displacement. METHODS: Consecutive patients undergoing primary RRD repair were assessed postoperatively with fundus autofluorescence and optical coherence tomography imaging, and the extent of macula displacement quantified using a novel means. Findings were examined for correlations with symptoms and pre-operative features. RESULTS: Macula displacement was evident postoperatively in 72% of 32 consecutive fovea-involving detachments treated with vitrectomy and gas. It was also evident in 5/17 foveal-sparing cases treated with vitrectomy and gas and in two of two patients with fovea-involving detachments treated with vitrectomy and oil. There was a significant correlation between the presence of macula displacement and symptoms of distortion in the early postoperative period (p=0.013). Symptomatic patients described bending of lines with or without objects appearing smaller or narrower in the operated eye. Quantifying the displacement demonstrated that the extent of displacement was associated with distance from the optic disc (p=0.005) and the extent of retinal detachment. CONCLUSIONS: Displacement of the macula is common following RRD repair and heterogeneous in nature. Most affected patients are symptomatic in the early postoperative period.