International harmonization of procedures for measuring and analyzing of vessel underwater radiated noise

The habitat of the endangered southern resident killer whale (SRKW) overlaps major international shipping lanes near the Port of Vancouver, British Columbia. Shipping is a dominant source of underwater noise, which can hinder SRKW key life functions. To reduce environmental pressure on the SRKWs, Vancouver Fraser Port Authority offers incentives for quieter ships. However, the absence of a widely accepted underwater radiated noise (URN) measurement procedure hinders the determination of relative quietness. We review URN measurement procedures, summarizing results to date from two Canadian-led projects aimed at improving harmonization of shallow-water URN measurement procedures: One supports the International Organization for Standardization (ISO) in the development of a URN measurement standard; the other supports the alignment of URN measurement procedures developed by ship classification societies. Weaknesses in conventional shallow-water URN metrics are identified, and two alternative metrics proposed. Optimal shallow-water measurement geometry is identified.

An international collaborative evaluation of central serous chorioretinopathy: different therapeutic approaches and review of literature. The European Vitreoretinal Society central serous chorioretinopathy study

PURPOSE

To study and compare the efficacy of different therapeutic options for the treatment of central serous chorioretinopathy (CSCR).

METHODS

This is a nonrandomized, international multicentre study on 1719 patients (1861 eyes) diagnosed with CSCR, from 63 centres (24 countries). Reported data included different methods of treatment and both results of diagnostic examinations [fluorescein angiography and/or optical coherent tomography (OCT)] and best-corrected visual acuity (BCVA) before and after therapy. The duration of observation had a mean of 11 months but was extended in a minority of cases up to 7 years. The aim of this study is to evaluate the efficacy of the different therapeutic options of CSCR in terms of both visual (BCVA) and anatomic (OCT) improvement.

RESULTS

One thousand seven hundred nineteen patients (1861 eyes) diagnosed with CSCR were included. Treatments performed were nonsteroidal anti-inflammatory eye drops, laser photocoagulation, micropulse diode laser photocoagulation, photodynamic therapy (PDT; Standard PDT, Reduced-dose PDT, Reduced-fluence PDT), intravitreal (IVT) antivascular endothelial growth factor injection (VEGF), observation and other treatments. The list of the OTHERS included both combinations of the main proposed treatments or a variety of other treatments such as eplerenone, spironolactone, acetazolamide, beta-blockers, anti-anxiety drugs, aspirin, folic acid, methotrexate, statins, vitis vinifera extract medication and pars plana vitrectomy. The majority of the patients were men with a prevalence of 77%. The odds ratio (OR) showed a partial or complete resolution of fluid on OCT with any treatment as compared with observation. In univariate analysis, the anatomical result (improvement in subretinal fluid using OCT at 1 month) was favoured by age <60 years (p < 0.005), no previous observation (p < 0.0002), duration less than 3 months (p < 0.0001), absence of CSCR in the fellow eye (p = 0.04), leakage outside of the arcade (p = 0.05) and fluid height >500 μm (p = 0.03). The OR for obtaining partial or complete resolution showed that anti-VEGF and eyedrops were not statistically significant; whereas PDT (8.5), thermal laser (11.3) and micropulse laser (8.9) lead to better anatomical results with less variability. In univariate analysis, the functional result at 1 month was favoured by first episode (p = 0.04), height of subretinal fluid >500 μm (p < 0.0001) and short duration of observation (p = 0.02). Finally, there was no statistically significant difference among the treatments at 12 months.

CONCLUSION

Spontaneous resolution has been described in a high percentage of patients. Laser (micropulse and thermal) and PDT seem to lead to significant early anatomical improvement; however, there is little change beyond the first month of treatment. The real visual benefit needs further clarification.

Evaluating the predictive strength of underwater noise exposure criteria for marine mammals

The aim of underwater noise exposure criteria in a regulatory context is to identify at what received levels noise-induced effects are predicted to occur, so that those effects may be appropriately considered in an evaluation or mitigation context under the respective regulatory regime. Special emphasis has been given to hearing related impairment of marine mammals due to their high sensitivity to and reliance on underwater sound. Existing regulations of underwater noise show substantial qualitative and quantitative discrepancies. A dataset acquired during an experiment that induced temporary threshold shift (TTS) in a harbor porpoise (Phocoena phocoena) from Lucke, Siebert, Lepper, and Blanchet [(2009). J. Acoust. Soc. Am. 125, 4060-4070] was reanalyzed to see if various exposure criteria predicted TTS differently for high-frequency cetaceans. This provided an unambiguous quantitative comparison of predicted TTS levels for the existing noise exposure criteria used by regulatory bodies in several countries. The comparative evaluation of the existing noise exposure criteria shows substantial disagreement in the predicted levels for onset for auditory effects. While frequency-weighting functions evolved to provide a better representation of sensitivity to noise exposure when compared to measured results at the criteria's onset, thresholds remain the most important parameter determining a match between criteria and measured results.

Techniques for distinguishing between impulsive and non-impulsive sound in the context of regulating sound exposure for marine mammals

Regulations designed to mitigate the effects of man-made sounds on marine mammal hearing specify maximum daily sound exposure levels. The limits are lower for impulsive than non-impulsive sounds. The regulations do not indicate how to quantify impulsiveness; instead sounds are grouped by properties at the source. To address this gap, three metrics of impulsiveness (kurtosis, crest factor, and the Harris impulse factor) were compared using values from random noise and real-world ocean sounds. Kurtosis is recommended for quantifying impulsiveness. Kurtosis greater than 40 indicates a sound is fully impulsive. Only sounds above the effective quiet threshold (EQT) are considered intense enough to accumulate over time and cause hearing injury. A functional definition for EQT is proposed: the auditory frequency-weighted sound pressure level (SPL) that could accumulate to cause temporary threshold shift from non-impulsive sound as described in Southall, Finneran, Reichmuth, Nachtigall, Ketten, Bowles, Ellison, Nowacek, and Tyack [(2019). Aquat. Mamm. 45, 125-232]. It is known that impulsive sounds change to non-impulsive as these sounds propagate. This paper shows that this is not relevant for assessing hearing injury because sounds retain impulsive character when SPLs are above EQT. Sounds from vessels are normally considered non-impulsive; however, 66% of vessels analyzed were impulsive when weighted for very-high frequency mammal hearing.

Abstract 503: Molecular characterization of in vivo isolated EpCAM-positive circulating tumor cells in breast cancer

Introduction: In the early stages of cancer, the chance to detect rare CTCs is increasing by increasing the sample volume. The aim of our study was to evaluate the diagnostic sensitivity of a novel clinical device for the in-vivo isolation of EpCAM-positive CTCs (CellCollectorTM, GILUPI, GmBH), by using highly sensitive RT-qPCR molecular assays.

Patients and methods: 29 breast cancer patients without overt metastases before the beginning of adjuvant chemotherapy (M0), 26 breast cancer patients with overt metastases before starting of therapy (M1) and 12/26 of them before the second cycle of therapy (M2), as well as 18 healthy donors participated in the study. After in-vivo isolation, total RNA was extracted from captured cells, lysed in Trizol, followed by cDNA synthesis. RT-qPCR was used for the molecular characterization of captured cells, for: CK-19, HER-2, TWIST1, VEGF, ER, PR, EGFR, CD44, CD24, and ALDH1, while B2M was used as a reference gene. Peripheral blood was also collected for CTC analysis by the FDA cleared CellSearchTM system. In addition, immunofluorescence staining of cytospins was performed and screened for CTCs using the ARIOL system, using ER, HER2, CK (8, 18, 19) and CD45 for CTC identification.

Results: Results are shown in Table 1. At least one gene was expressed in 10(34.5%) of M0, 15(57.7%) of M1 and 4(33.3%) of M2 patient groups, but in none of healthy donors 0/18(0%). CellSearchTM gave positive results in 5(17.2%) of M0, 10(38.5%) of M1 and 0(0%) of M2. Immunofluorescence (Ariol system) was positive for ER, HER2, CK (8, 18, 19) in 5/15(33.3%) M0, in 4/12(33.3%) M1 and in 1/7(14.3%) M2 groups. Table 1.Gene expression in CTCHealthy N = 18M0 N = 29M1 N = 26M2 N = 12CK-190 (0%)6(20.7%)6 (23.1%)2 (16.7%)HER20 (0%)2 (6.9%)0 (0%)0 (0%)ER0 (0%)2 (6.9%)0 (0%)0 (0%)PR0 (0%)0 (0%)0 (0%)0 (0%)EGFR0 (0%)0 (0%)0 (0%)0 (0%)TWIST10 (0%)1 (3.4%)0 (0%)2 (16.7%)VEGF0 (0%)3 (10.3%)5 (19.2%)1 (8.3%)CD44+/CD24−,0 (0%)4 (13.8%)3 (11.5%)1 (8.3%)ALDH1high/CD24−,0 (0%)2 (6.9%)8 (30.8%)1(8.3%)

Conclusions: In-vivo isolation of CTC is minimally invasive, and in combination with high specific and sensitive RT-qPCR assays for CTC detection and molecular characterization seems promising. Comparison studies with the CellSearch and immunofluorescence have shown poor agreement. These results should be validated in large patient cohorts, and in respect to the clinical outcome.

Citation Format: Areti D. Strati, Martha Zavridou, Galateia Kallergi, Eleni Politaki, Tobias Gorges, Andra Kuske, Anna-Lena Bohnen, George Koutsodontis, Amanda Psyrri, Klaus Lucke, Vasilis Georgoulias, Klaus Pantel, Evi Lianidou. Molecular characterization of in vivo isolated EpCAM-positive circulating tumor cells in breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 503.

Assessing auditory evoked potentials of wild harbor porpoises (Phocoena phocoena)

Testing the hearing abilities of marine mammals under water is a challenging task. Sample sizes are usually low, thus limiting the ability to generalize findings of susceptibility towards noise influences. A method to measure harbor porpoise hearing thresholds in situ in outdoor conditions using auditory steady state responses of the brainstem was developed and tested. The method was used on 15 live-stranded animals from the North Sea during rehabilitation, shortly before release into the wild, and on 12 wild animals incidentally caught in pound nets in Denmark (inner Danish waters). Results indicated that although the variability between individuals is wide, the shape of the hearing curve is generally similar to previously published results from behavioral trials. Using 10-kHz frequency intervals between 10 and 160 kHz, best hearing was found between 120 and 130 kHz. Additional testing using one-third octave frequency intervals (from 16 to 160 kHz) allowed for a much faster hearing assessment, but eliminated the fine scale threshold characteristics. For further investigations, the method will be used to better understand the factors influencing sensitivity differences across individuals and to establish population-level parameters describing hearing abilities of harbor porpoises.

Auditory sensitivity in aquatic animals

A critical concern with respect to marine animal acoustics is the issue of hearing "sensitivity," as it is widely used as a criterion for the onset of noise-induced effects. Important aspects of research on sensitivity to sound by marine animals include: uncertainties regarding how well these species detect and respond to different sounds; the masking effects of man-made sounds on the detection of biologically important sounds; the question how internal state, motivation, context, and previous experience affect their behavioral responses; and the long-term and cumulative effects of sound exposure. If we are to better understand the sensitivity of marine animals to sound we must concentrate research on these questions. In order to assess population level and ecological community impacts new approaches can possibly be adopted from other disciplines and applied to marine fauna.

Communication masking in marine mammals: A review and research strategy

Underwater noise, whether of natural or anthropogenic origin, has the ability to interfere with the way in which marine mammals receive acoustic signals (i.e., for communication, social interaction, foraging, navigation, etc.). This phenomenon, termed auditory masking, has been well studied in humans and terrestrial vertebrates (in particular birds), but less so in marine mammals. Anthropogenic underwater noise seems to be increasing in parts of the world's oceans and concerns about associated bioacoustic effects, including masking, are growing. In this article, we review our understanding of masking in marine mammals, summarise data on marine mammal hearing as they relate to masking (including audiograms, critical ratios, critical bandwidths, and auditory integration times), discuss masking release processes of receivers (including comodulation masking release and spatial release from masking) and anti-masking strategies of signalers (e.g. Lombard effect), and set a research framework for improved assessment of potential masking in marine mammals.

Seasonal migrations of North Atlantic minke whales: novel insights from large-scale passive acoustic monitoring networks

BACKGROUND

Little is known about migration patterns and seasonal distribution away from coastal summer feeding habitats of many pelagic baleen whales. Recently, large-scale passive acoustic monitoring networks have become available to explore migration patterns and identify critical habitats of these species. North Atlantic minke whales (Balaenoptera acutorostrata) perform seasonal migrations between high latitude summer feeding and low latitude winter breeding grounds. While the distribution and abundance of the species has been studied across their summer range, data on migration and winter habitat are virtually missing. Acoustic recordings, from 16 different sites from across the North Atlantic, were analyzed to examine the seasonal and geographic variation in minke whale pulse train occurrence, infer information about migration routes and timing, and to identify possible winter habitats.

RESULTS

Acoustic detections show that minke whales leave their winter grounds south of 30° N from March through early April. On their southward migration in autumn, minke whales leave waters north of 40° N from mid-October through early November. In the western North Atlantic spring migrants appear to track the warmer waters of the Gulf Stream along the continental shelf, while whales travel farther offshore in autumn. Abundant detections were found off the southeastern US and the Caribbean during winter. Minke whale pulse trains showed evidence of geographic variation, with longer pulse trains recorded south of 40° N. Very few pulse trains were recorded during summer in any of the datasets.

CONCLUSION

This study highlights the feasibility of using acoustic monitoring networks to explore migration patterns of pelagic marine mammals. Results confirm the presence of minke whales off the southeastern US and the Caribbean during winter months. The absence of pulse train detections during summer suggests either that minke whales switch their vocal behaviour at this time of year, are absent from available recording sites or that variation in signal structure influenced automated detection. Alternatively, if pulse trains are produced in a reproductive context by males, these data may indicate their absence from the selected recording sites. Evidence of geographic variation in pulse train duration suggests different behavioural functions or use of these calls at different latitudes.

In-air evoked potential audiometry of grey seals (Halichoerus grypus) from the North and Baltic Seas

In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1–20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ≤40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4–20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal.

The use of an air bubble curtain to reduce the received sound levels for harbor porpoises (Phocoena phocoena)

In December 2005 construction work was started to replace a harbor wall in Kerteminde harbor, Denmark. A total of 175 wooden piles were piled into the ground at the waters edge over a period of 3 months. During the same period three harbor porpoises were housed in a marine mammal facility on the opposite side of the harbor. All animals showed strong avoidance reactions after the start of the piling activities. As a measure to reduce the sound exposure for the animals an air bubble curtain was constructed and operated in a direct path between the piling site and the opening of the animals' semi-natural pool. The sound attenuation effect achieved with this system was determined by quantitative comparison of pile driving impulses simultaneously measured in front of and behind the active air bubble curtain. Mean levels of sound attenuation over a sequence of 95 consecutive pile strikes were 14 dB (standard deviation (s.d.) 3.4 dB) for peak to peak values and 13 dB (s.d. 2.5 dB) for SEL values. As soon as the air bubble curtain was installed and operated, no further avoidance reactions of the animals to the piling activities were apparent.

Trouble-shooting deployment and recovery options for various stationary passive acoustic monitoring devices in both shallow- and deep-water applications

Deployment of any type of measuring device into the ocean, whether to shallow or deeper depths, is accompanied by the hope that this equipment and associated data will be recovered. The ocean is harsh on gear. Salt water corrodes. Currents, tides, surge, storms, and winds collaborate to increase the severity of the conditions that monitoring devices will endure. All ocean-related research has encountered the situations described in this paper. In collating the details of various deployment and recovery scenarios related to stationary passive acoustic monitoring use in the ocean, it is the intent of this paper to share trouble-shooting successes and failures to guide future work with this gear to monitor marine mammal, fish, and ambient (biologic and anthropogenic) sounds in the ocean-in both coastal and open waters.

[Visual development of postoperative persistent macular holes with and without surgical revision]

BACKGROUND

Postoperative persistent macular holes after vitrectomy are a rare, but typical phenomenon. Without further surgical intervention the visual acuity remains unchanged. There are no generally accepted treatment recommendations for these cases. We report on 23 cases with postoperative persistent macular holes with and without further surgical treatment and analyzed the clinical outcome.

METHODS

A retrospective case control study was performed and visual acuity and anatomic status of the macular holes were analysed in 23 cases with a persistent macular hole after previous vitrectomy. Seven patients refused further surgical treatment (group 1) and were used as a control group. Three patients received a second intravitreal gas tamponade without further surgical manipulation (group 2). A vitrectomy revision with endotamponade was performed in 13 eyes (group 3). Additional autologous blood on the macular hole was used in 4 cases and adjuvant ICG-assisted peeling of the inner limiting membrane around the macular hole was performed in another 9 cases.

RESULTS

The eyes of group 1 showed a statistically not significant (p = 0.56) change of the median LogMAR visual acuity from 1.3 (range 0.7 - 1.4) to 1.2 (range 0.3 - 2.0) over a median follow-up of 11.8 months. No eye in group 2 developed a closure of the macular hole. After a median follow-up of 3.6 months the LogMAR visual acuity dropped statistically not significantly from 0.7 (range 0.7 - 1.9 to 1.0 (range 0.8 - 1.0; p = 0.5). 61 % of eyes showed a closure of the macular hole after a second vitrectomy (group 3). Eight out of 16 retreated eyes had finally a persistent macular hole. In these cases median LogMAR visual acuity decreased insignificantly from 1.0 (range 0.7 - 1.4) to 1.1 (range 0.7 - 1.4; p = 0.27) during a median follow-up of 13.7 months. In 8 eyes with a finally closed macular hole median LogMAR visual acuity increased statistically significantly from 0.8 (rage 0.4 - 1.3) to 0.35 (range 0.04 - 0.9; p = 0.016) after a median follow-up of 8.1 months.

CONCLUSION

Surgical revision of postoperative persistent macular holes using vitrectomy and endotamponade showed a success rate of 61 %. Eyes that had unsuccessful subsequent surgery had a slight decay of the visual acuity during the follow-up that was similar to that of eyes without further surgical treatment. In contrast, the final closure of the macular hole after a second surgery was associated with a significantly increased visual acuity.

Temporary shift in masked hearing thresholds in a harbor porpoise (Phocoena phocoena) after exposure to seismic airgun stimuli

An auditory study was conducted to derive data on temporary threshold shift (TTS) induced by single impulses. This information should serve as basis for the definition of noise exposure criteria for harbor porpoises. The measurements of TTS were conducted on a harbor porpoise by measuring the auditory evoked potentials in response to amplitude-modulated sounds. After obtaining baseline hearing data the animal was exposed to single airgun stimuli at increasing received levels. Immediately after each exposure the animal's hearing threshold was tested for significant changes. The received levels of the airgun impulses were increased until TTS was reached. At 4 kHz the predefined TTS criterion was exceeded at a received sound pressure level of 199.7 dB(pk-pk) re 1 microPa and a sound exposure level (SEL) of 164.3 dB re 1 microPa(2) s. The animal consistently showed aversive behavioral reactions at received sound pressure levels above 174 dB(pk-pk) re 1 microPa or a SEL of 145 dB re 1 microPa(2) s. Elevated levels of baseline hearing sensitivity indicate potentially masked acoustic thresholds. Therefore, the resulting TTS levels should be considered masked temporary threshold shift (MTTS) levels. The MTTS levels are lower than for any other cetacean species tested so far.

Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes

AIM

To evaluate the effect of verteporfin photodynamic therapy (PDT) on endostatin with regard to expression of vascular endothelial growth factor (VEGF) in human choroidal neovascular membranes (CNVs) secondary to age-related macular degeneration.

METHODS

A retrospective review of an interventional case series of 68 patients who underwent removal of CNV. 29 patients were treated with PDT 3-655 days before surgery. 39 CNVs without previous treatment were used as controls. CNVs were stained for CD34, CD105, Ki-67, cytokeratin 18, endostatin, E-selectin and VEGF. "Predominance score of VEGF over endostatin" (mean) was defined as the difference between VEGF and endostatin staining scores.

RESULTS

In four CNVs treated by PDT 3 days previously, PS was significantly higher in the retinal pigment epithelium (mean = 2.5, p = 0.006) and stroma (mean = 2, p = 0.015) than in the control group (mean = 0). At longer post-PDT intervals, PS was significantly decreased in the retinal pigment epithelium (mean = 0, p = 0.019) and stroma (mean = 0, p = 0.015). Proliferative activity was high (p = 0.023), but mostly related to inflammatory cells. PDT did not influence E-selectin expression significantly.

CONCLUSIONS

VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.

Expression of endostatin in human choroidal neovascular membranes secondary to age-related macular degeneration

Endostatin is an endogenous angiogenesis inhibitor which requires E-selectin for its antiangiogenic activity. The aim of this study was to investigate the expression of endostatin in human choroidal neovascular membranes (CNV) secondary to age-related macular degeneration (AMD) with regard to vascularization and proliferative activity. An interventional case series of 36 patients who underwent removal of CNV were retrospectively investigated. Thirty-six CNV were analyzed by light microscopic immunohistochemistry for the expression of CD34 (endothelial cells, EC), CD105 (activated EC), Ki-67 (cell proliferation), Cytokeratin 18 (epithelial cells), VEGF (vascular endothelial growth factor), E-selectin and endostatin. Donor eyes (n=7) including one with AMD were used as controls. Endostatin immunoreactivity was present in choroidal vessels of five as well as in the retinal pigment epithelium (RPE)-Bruch's membrane complex of two donor eyes without AMD. In one eye with AMD, endostatin was detected in RPE, Bruch's membrane and choroidal vessels. Ninety-two percent (33/36) of CNV disclosed endostatin staining. RPE-Bruch's membrane complex, choroidal vessels and stroma were positive in 50% (18/36), 72% (26/36), and 78% (28/36) of the membranes, respectively. Both control eyes and CNV expressed all the investigated markers except E-selectin being positive only in membranes. Endostatin, an endogenous angiogenesis inhibitor, is expressed in CNV and its therapeutic up-regulation may be a new strategy in the treatment of neovascular AMD.

Antennae on transmitters on penguins: balancing energy budgets on the high wire

The effect of externally mounted antennae on the energetics of penguins was studied by mounting various antennae on a transducer fixed to a model Magellanic penguin Spheniscus magellanicus to determine drag, run at speeds of up to 2 m s(-1) in a swim canal. For rigid antennae set perpendicular to the water flow, measured drag increased with increasing swim speed. Increasing antenna length (for lengths between 100 and 200 mm) or diameter (for diameters between 1 and 4 mm) resulted in accelerating increased drag as a function of both antenna length and diameter. Where antennae were positioned at acute angles to the water flow, drag was markedly reduced, as was drag at higher speeds in flexible antennae. These results were incorporated in a model on the foraging energetics of free-living Magellanic penguins using data (on swim speeds, intervals between prey encounters, amount ingested per patch and dive durations) derived from previously published work and from a field study conducted on birds from a colony at Punta Norte, Argentina, using data loggers. The field work indicated that free-living birds have a foraging efficiency (net energy gain/net energy loss) of about 2.5. The model predicted that birds equipped with the largest rigid external antennae tested (200 mm x 3 mm diameter), set perpendicular to water flow, increased energy expenditure at normal swim speeds of 1.77 m s(-1) by 79% and at prey capture speeds of 2.25 m s(-1) by 147%, and ultimately led to a foraging efficiency that was about 5 times less than that of unequipped birds. Highly flexible antennae were shown to reduce this effect considerably. Deleterious antenna-induced effects are predicted to be particularly critical in penguins that have to travel fast to capture prey. Possible measures taken by the birds to increase foraging efficiency could include reduced travelling speed and selection of smaller prey types. Suggestions are made as to how antenna-induced drag might be minimized for future studies on marine diving animals.

Chronic cystoid macular edema in an eye with a capsule defect and posteriorly dislocated capsular tension ring

A 72-year-old man presented with visual deterioration and cystoid macular edema (CME) 9 months after cataract surgery elsewhere. A slitlamp examination showed a large posterior capsule defect and a slightly decentered intraocular lens (IOL). In addition, a curved poly(methyl methacrylate) (PMMA) haptic-like structure was seen behind the IOL in the superoanterior vitreous cavity. The foreign body was entangled by vitreous fibers and moved in accordance with ocular motility. A broken PMMA haptic was suspected. During vitrectomy for removal of the suspected IOL haptic, an intact, posteriorly dislocated capsular tension ring (CTR) was found. It was cut in 2 and excised carefully via the sclerectomies. Postoperatively, the CME resolved and vision improved.

Clinicopathologic correlation in hemorrhagic age-related macular degeneration

PURPOSE

To analyze and compare the histopathology of surgically extracted membranes in hemorrhagic age-related macular degeneration (AMD) versus extracted classic, mixed and occult choroidal neovascularization (CNV) in AMD.

METHODS

Thirty consecutive membranes, surgically removed in hemorrhagic AMD, were analyzed and compared with consecutive series of 50 classic, 20 mixed and 20 occult membrane specimens in exudative AMD. The specimens were serially sectioned and stained in a stepped fashion with hematoxylin-eosin, Masson trichrome and periodic acid-Schiff stain.

RESULTS

Diffuse drusen were observed in all hemorrhagic AMD specimens, fibrovascular tissue was found in 29 of 30 specimens which was located subretinally in 11 specimens and/or in Bruch's membrane in 28 specimens. A hemorrhage was located subretinally in 21 specimens, in the stroma of the fibrovascular tissue in 17 specimens, at the choroidal side of the diffuse drusen adjacent to fibrovascular tissue in 13 specimens and at the choroidal side of the fibrovascular tissue in Bruch's membrane in 8 specimens. Grossly dilated thin-walled vessels were identified in one hemorrhagic AMD case, suggestive of polypoidal choroidal vasculopathy. Scarred tears of the retinal pigment epithelium were identified in two specimens.

CONCLUSION

A large spectrum of histo-architectural lesions is recognized in hemorrhagic maculopathy. Hemorrhages do not only characteristically appear in the subretinal space or in the stroma of the neovascular tissue but also at the choroidal side of the diffuse drusen adjacent to the neovascular complex and at the choroidal side of the intra-Bruch's fibrovascular tissue.

Peripheral visual field loss after vitreous surgery for macular holes

BACKGROUND

Vitreous surgery for Idiopathic macular holes can result in both anatomic closure of the hole and visual improvement. In some patients even normal visual acuity is achieved. Postoperative visual field loss is a newly recognized complication. This prospective study evaluates the frequency and significance of scotomas after vitrectomy with gas tamponade for stage I-IV macular holes.

METHODS

Over a period of 10 months, a consecutive series of 30 patients and 31 eyes with macular holes underwent pre- and postoperative automatic perimetry (Octopus 07, 70 degrees) and macular perimetry (Octopus M1, 24 degrees) to characterize the pattern of visual field defects after vitrectomy with gas tamponade. Success rates were evaluated and complications were analyzed.

RESULTS

Anatomic success after one surgical procedure was achieved in 85% of cases, visual improvement in 58%. Some 70.1% of patients had peripheral scotomas postoperatively; some of these were highly symptomatic and others were detected by visual field testing only. The most consistently affected areas were the temporal and lower periphery of the visual field. The central visual field, however, was not disturbed.

CONCLUSION

Visual field loss after otherwise successful surgery for macular holes is an unexpectedly frequent and serious complication. The authors discuss various factors that may contribute to the postoperative scotomas. From the localization of the scotomas it seems most likely that they are caused by the persistent pressure of the gas bubble on the peripheral retina. Further investigations are necessary to confirm this hypothesis, and ways must be found to avoid this complication in order to be able to proceed with this otherwise promising new indication group for vitreous surgery.

[Endotamponade with silicon oil in severe proliferative retinopathy with attached retina]

Silicone oil as endotamponade in cases with attached retina is only indicated in a few very selected cases. These are cases with a high risk of intravitreal hemorrhage and a need for quick visual rehabilitation. We examined 23 patients, who had undergone pars plana vitrectomy and silicone oil filling. All patients were diabetics with proliferative retinopathy and recurrent intravitreal hemorrhage. In 14 cases it was the only eye; 11 eyes previously had a vitrectomy. We analyzed these cases for visual acuity, rubeosis, bleeding tendency, reproliferations, cataract development and glaucoma. The follow-up time was 32 months. In 22 of 23 eyes quick visual rehabilitation was achieved, and the patients had at least ambulatory vision within the first week. In one case poor visual acuity was due to exudative maculopathy. No relevant bleeding occurred. In 14 of 16 phacic patients we observed a cataract. Seven patients developed glaucoma, which was due to neovascularization in 5 cases. It was successfully treated in all cases and no visual loss occurred. In 5 cases we observed a peripheral traction retinal detachment, in one case a traction retinal detachment at the posterior pole. In selected cases silicone oil can prevent recurrent intravitreal hemorrhage, allowing rapid visual recovery. Considering the complications, the silicone oil should be removed as soon as possible.

[Experimental studies of the risks of endocapsular polymerization of injectable intraocular lenses]

Various experimental lens refilling procedures have been proposed. One of these methods uses endocapsular polymerization of the injected material by light exposure. In this study we wanted to characterize the potential risks of this procedure due to light and temperature hazards. We performed in vitro experiments on enucleated pig eyes and an in vivo study on 15 rabbits. During the polymerization process the highest temperature recorded (45.1 degrees C) was measured at the posterior lens capsule for a few seconds. The measured irradiance (0.065 W/cm2) and the risk of photochemical damage to the retina during 20 s of polymerization was comparable to that caused by 1.5 min of standard coaxial illumination with our operating microscope. In vivo we found no serious inflammatory reactions except for four cases where surgical problems had occurred. No direct retinal damage could be detected histopathologically. In conclusion, we think that lens refilling and endocapsular polymerization are promising techniques. However, refilling materials with better physical properties than those available so far need to be developed.

Vitreoretinal surgery in advanced Coat's disease

Massive subretinal exudates as well as vitreal traction often induce complicated retinal detachments in patients with advanced Coats' disease. If left untreated, most patients experience secondary glaucoma by rubeosis and phthisis bulbi in addition to irreversible visual loss. We report on the surgical procedures used and results obtained in three patients aged between 21 and 28 years with combined exudative and traction-induced detachment. In all cases, extensive but unsuccessful retinal coagulation had been performed. The surgical intervention was done by application of an encircling buckle followed by vitrectomy and removal of preretinal membranes and subretinal lipid exudates via retinectomies. Particular attention was paid to the intensive endodiathermy of retinal teleangiectasies during surgery. Surgery was concluded by siliconeoil tamponade. Postoperatively, progressive resorption of remaining exudates and teleangiectatic vessels could be observed. All patients demonstrated stable functional and anatomic results at the last follow-up examination performed at 13 months to 6 years after surgery. A stabilization of the anatomic and functional situation can be achieved even in advanced cases of Coats'-induced traction retinal detachment by vitreoretinal surgery.

[Clinical heterogeneity of non-Hodgkin's lymphoma of the eye with extraocular manifestations]

Primary, ocular Non-Hodgkin lymphoma is a multicentric disease. The prognosis is mostly determined by involvement of the central nervous system and/or visceral organs. Since ocular symptoms often precede accompanying manifestations and since the eye is easily accessible to diagnostic measures, the ophthalmological diagnosis is essential for early detection and treatment of this complex disease, which has a poor prognosis. To illustrate the extraordinary heterogeneity of the clinical symptoms, four case reports have been selected which demonstrate various ocular symptoms and extraocular localizations. The ophthalmological variability ranges from typical uveitis to retinitis and vasculitis with varying symptoms during the progression of the disease. Completely different extraocular features were induced by long-standing, local infiltrates within basal ganglia, a diffuse infiltration of the brain leading to an acute increase in intracranial pressure, a peripheral tumour within the spinal channel or massive infiltrates of liver, lung and kidneys. Lack of pathognomonic features, high clinical variability and the limited value of imaging techniques and histopathological measures often lead to serious delays in diagnosis.

Lens refilling and endocapsular polymerization of an injectable intraocular lens: in vitro and in vivo study of potential risks and benefits

Endocapsular cataract removal and injection of a liquid artificial lens has several advantages, including restitution of accommodation, small corneoscleral incision, a more physiological position of the intraocular lens, and a reduced rate of secondary opacification. Our technique consists of bimanual phacofragmentation followed by injection of a fluid monomeric material that can be polymerized inside the capsular bag by short light exposure. Our study assessed the potential risks of the technique (e.g., heat damage to ocular tissue, light damage to the retina) and investigated the technique in vivo. We performed in vitro experiments on porcine cadaver eyes and an in vivo study on 15 rabbits. After a clinical follow-up of at least 12 weeks, the eyes were investigated histopathologically. During the polymerization process, the highest temperature measured at the posterior lens capsule was 45.1 degrees Celsius for a few seconds. The measured irradiance (0.065 watts per cm2) and the risk of photochemical damage to the retina during 20 seconds of polymerization were comparable to that caused by 1.5 minutes of standard coaxial illumination with the operating microscope. In vivo there were no serious inflammatory reactions except in four cases in which there had been intraoperative problems. The rate of secondary opacification appeared less than in conventional intraocular lens implantation in rabbits, especially when the capsule refilled completely. Retinal damage could not be detected histopathologically. In conclusion, refilling techniques may be successful once appropriate refilling materials become available.

[Silicone oil in surgery of complicated retinal detachment]

Silicone oil has established itself as an internal tamponade in the treatment of complicated retinal detachments. The most common indications are PVR, advanced proliferative diabetic retinopathy, giant tears and severe trauma to the posterior segment of the eye. Other rarer indications have meanwhile been added. By its use success rates can be achieved that were thought impossible only ten years ago. Serious complications such as secondary glaucoma and keratopathy, much dreaded in the early years of its use, are better understood and are generally not considered contraindications anymore. Secondary glaucoma occurs in about 20% of eyes, has a wide variety of causes and is rarely attributable to the silicone oil itself, provided purified and highly viscous oil is used. The development of keratopathies has been greatly reduced by the introduction of the Andoiridectomy and this complication is now largely confined to eyes with severe trauma, hypotony or aniridia. Toxic effects of silicone oil have so far not been convincingly demonstrated. Whereas similar results can be obtained by the use of long-acting intraocular gases in milder cases of the conditions described, silicone oil tamponade has proved to be an effective treatment in the more advanced forms of complicated retinal detachments.

[Removal of silicone oil in treatment of so-called emulsification glaucoma]

We investigated whether emulsification glaucoma after silicone oil implantation can be influenced positively by removal of the oil. In 16 of 264 patients successfully operated upon with purified silicone oil 5000 cps, we found a glaucoma refractory to medical therapy and probably caused by emulsification. We removed the silicone oil from these eyes and followed them up for a period of 6 months (12.5 +/- 7.3 months). In 12 of the 16 eyes, the intraocular pressures were normalized after silicone oil removal with or without antiglaucomatous therapy. Four eyes showed raised intraocular pressures in spite of silicone oil removal. These could, however, be largely explained by neovascularization or chronic inflammation with increasing anterior synechia formation. In eyes with possible emulsification glaucoma, early and thorough removal of the silicone oil is therefore recommended since this can result in normalization of intraocular pressures in a large percentage of cases.

[Fluorescein angiography findings after retinotomy and retinectomy]

Drainage-retinotomies and relaxing retinectomies are helpful techniques in extreme vitreoretinal surgery. They have become established as a surgical instrument, but their possible pathophysiologic effects on the retina, pigment epithelium and choroid have not been investigated as yet. 30 Patients with retinotomies or retinectomies after vitrectomy with silicone oil filling for advanced proliferative vitreoretinopathy were studied angiographically. Fluorescein angiographic findings revealed 1. a predominant effect of endophotocoagulation in the area of the retinotomy/retinectomy with occlusion of the choriocapillaris and hyperpigmentation and window effects of the retinal pigment epithelium, but sometimes there was a localized traction effect with retinal and choroidal folds, 2. that retinal perfusion is unaffected in untreated and coagulated areas without evidence for a breakdown of the blood-retina-barrier or retinal ischemia, 3. an intact blood-retinal-barrier in areas of uncovered retinal pigment epithelium, 4. no evidence for significant reproliferations in the areas of retinotomies and retinectomies, 5. choroidal neovascular membranes which may occur postoperatively at the retinotomy site probably as a complication for intraoperative injury of Bruch's membrane, 6. a cystoid macular edema, an optic atrophy, pigment-fallout, depigmented tracks and choroidal folds as unspecific findings post retinal detachment surgery. The angiographic data support the clinical impression, that retinotomies and retinectomies performed in otherwise untreatable cases cause no significant damage in the attached retina.

[Results after retinotomy and retinectomy in the treatment of complicated retinal detachment]

Of 241 cases operated with pars-plana vitrectomy and silicone oil filling for complicated retinal detachment we performed retinotomies for drainage of subretinal fluid or removal of subretinal strands in 48 cases (20%) and retinectomies for relief of traction in 80 cases (33%). We found no negative influence of these retinotomies and retinectomies on the anatomic or functional outcome in our major indication groups--PVR, PDR and perforating injury. With increasing size of the retinectomy the anatomic success rate fell from 100% in cases with a 90 degrees retinectomy to 76% with a retinectomy larger than 270 degrees. In 21 out of 80 cases traction relief was insufficient so that we had to enlarge the retinectomy. 17 of these 21 cases could then be attached permanently.

[Secondary glaucoma after silicone oil surgery]

In spite of advances in surgical technique and the development of purified silicone oils, secondary glaucoma still develops in 10-20% of cases following silicone oil surgery. In the first part of this study it is shown by life-table analysis that factors such as early lens removal, inferior iridectomy, early silicone removal or the use of purified silicone oil have little or no influence on the development of glaucoma. In the second part an attempt is made to pinpoint possible causes of secondary glaucoma by re-examining all cases in which elevated intraocular pressure developed some time after silicone oil surgery. It was found that a multitude of factors (e.g., inflammation, angle-block, anterior peripheral synechiae and emulsification) were involved in the pathogenesis of temporary or persistent secondary glaucomas. In most cases pre-existing pathology was found to be responsible rather than the silicone oil itself. The majority of the cases in which the silicone oil caused secondary glaucoma by emulsification responded well to medication alone or removal of the silicone oil.

[Acute retinal necrosis]

The authors report on three patients with acute retinal necrosis who were treated with the virostatic agent Acyclovir and who underwent vitreoretinal surgery with silicone oil filling for total retinal detachment. In two eyes the retina was reattached, but useful vision was only preserved in one patient. Titers from blood and the vitreous, as well as microscopic findings in retinal biopsies, support the view that the necrosis is caused by a herpes simplex virus infection. After therapy with Acyclovir was instituted no further progression on the necrosis was observed. However, the development of retinal detachment could not be prevented. Early diagnosis and antiviral therapy are essential to improve the otherwise poor prognosis in this rare syndrome.

Effect of intravitreal liquid silicone on optic nerve function

We recorded visual-evoked cortical potentials before and after pars plana vitrectomy and intravitreal liquid silicone filling in 30 patients (30 eyes) with complicated retinal detachments without vascular eye disease or glaucoma. The flash- and flicker-evoked cortical potentials increased in amplitude in all cases. Of 21 eyes followed up for more than 50 days, eight had a 30-Hz flicker response before and after surgery. Of 13 eyes with preoperatively reduced flicker-frequency responses, ten (77%) were improved after surgery. The visual-evoked cortical potential parameters did not deteriorate in any of the patients. We concluded that no toxic effect of intravitreal liquid silicone on the optic nerve could be shown by electrophysiologic methods.

[Development and current status of silicone oil surgery]

On the basis of a series of 500 patients the authors describe the development of silicone oil surgery, the surgical technique, and present-day indications for it, as well as the results that can be achieved with this procedure. The postoperative problems (cataract, glaucoma, and keratopathy) are analyzed and guidelines presented for reducing the complication rate.

[Retinal complications of pars plana vitrectomy]

A series of 500 consecutive pars plana vitrectomies was evaluated with regard to retinal complications. If the retina is attached preoperatively the risk of retinal complications is only 2.0%; however, in cases with preoperative detachment it rises to 9.2%. When membrane peeling is performed the risk rises by a further 7.3%. These statistics support the view that early vitrectomy is today a safe operation in cases with a simple initial anatomical situation. In contrast, late vitrectomy in cases where the initial anatomical situation is complex and membrane-peeling has to be performed is necessarily associated with a higher rate of complications.