Bioenergetics, Trophic Ecology, and Niche Separation of Tunas.

Tunas are highly specialized predators that have evolved numerous adaptations for a lifestyle that requires large amounts of energy consumption. Here we review our understanding of the bioenergetics and feeding dynamics of tunas on a global scale, with an emphasis on yellowfin, bigeye, skipjack, albacore, and Atlantic bluefin tunas. Food consumption balances bioenergetics expenditures for respiration, growth (including gonad production), specific dynamic action, egestion, and excretion. Tunas feed across the micronekton and some large zooplankton. Some tunas appear to time their life history to take advantage of ephemeral aggregations of crustacean, fish, and molluscan prey. Ontogenetic and spatial diet differences are substantial, and significant interdecadal changes in prey composition have been observed. Diet shifts from larger to smaller prey taxa highlight ecosystem-wide changes in prey availability and diversity and provide implications for changing bioenergetics requirements into the future. Where tunas overlap, we show evidence of niche separation between them; resources are divided largely by differences in diet percentages and size ranges of prey taxa. The lack of long-term data limits the ability to predict impacts of climate change on tuna feeding behaviour. We note the need for systematic collection of feeding data as part of routine monitoring of these species, and we highlight the advantages of using biochemical techniques for broad-scale analyses of trophic relations. We support the continued development of ecosystem models, which all too often lack the regional-specific trophic data needed to adequately investigate climate and fishing impacts.

Glistenings with long-term follow-up of the Surgidev B20/20 polymethylmethacrylate intraocular lens.

PURPOSE: To evaluate the incidence and progression of small refractile vacuoles in a consecutive series of patients implanted with the Surgidev B20/20 (Surgidev Corporations, Goleta, California) polymethylmethacrylate intraocular lens. METHODS: Observational case series. A 4-year prospective study of the progression of glistenings in patients implanted with the Surgidev B20/20 intraocular lenses. In a consecutive series of 51 patients (73 eyes) that received the Surgidev B20/20 intraocular lens onset, number, and location of intraocular lens glistenings, best-corrected visual acuity, and associated ocular pathology were noted. RESULTS: With mean follow-up of 98 +/- 27 months (range, 48 to 176 months), 65 of 73 (89%) eyes had intraocular lens glistenings. Glistenings increased in frequency and size with increasing follow-up (P =.001). CONCLUSION: Glistenings may occur in polymethylmethacrylate intraocular lenses with long-term follow-up, and they are progressive.

Patient satisfaction after uneventful cataract surgery with implantation of a silicone or acrylic foldable intraocular lens. Comparative study.

PURPOSE: To compare patient satisfaction with vision 12 months after implantation of a silicone or acrylic foldable intraocular lens (IOL). SETTING: John A. Moran Eye Center, University of Utah Medical Center, Salt Lake City, Utah, USA. METHODS: Selection criteria included patients who had uneventful cataract extraction by phacoemulsification with a temporal clear corneal incision or superior scleral tunnel incision, a curvilinear capsulorhexis, and in-the-bag IOL placement. One hundred sixty-two patients surveyed had a mean follow-up of approximately 15 months (range 12 to 18 months). Patients were divided into 3 groups of 54 each based on IOL type: AMO SI-30/40, Alcon MA30BA, and Alcon MA60BA. All patients were surveyed over the telephone using a standardized questionnaire protocol. They were questioned about their perception of vision with best optical correction in relation to visual blurring symptoms, glare symptoms, night vision, near vision, and overall vision. RESULTS: There were no significant differences in patient satisfaction among the 3 IOL groups in visual blurring or night vision. Patients in the SI-30/40 and MA60BA groups reported significantly higher satisfaction with glare symptoms, near vision, and overall satisfaction than patients in the MA30BA group. CONCLUSION: The SI-30/SI-40 and the MA60BA IOLs received significantly higher patient satisfaction scores than the MA30BA IOL in glare symptoms, near vision, and overall satisfaction.

Introduction of corneal astigmatism through placement of a scleral fixation ring in eye bank eyes.

PURPOSE: To determine the effect of scleral fixation ring placement in induction of astigmatism by topographic analysis. METHODS: Baseline measurements were used in human eyes from the Utah Lions Eye Bank. In two control eyes, the effect of placing and replacing the eye in the holder was determined. In nine eyes, the effect of placing a 14-mm ring 2.0-mm from the limbus and an 18-mm ring 4.0-mm from the limbus, both in line with and between the rectus muscles, was determined. Induced astigmatism (IA) was determined by Alpins' vector analysis method. RESULTS: Control eyes had a mean variation of 0.26 +/- 0.18 diopters (D) (range, 0.07-0.65). The study eyes had a mean IA of 1.55 D with statistically significant differences noted when comparing 14-mm rings (0.92 +/- 2.00 D) versus 18-mm rings in line with the rectus (3.02 +/- 1.49 D; p = 0.02), with 18-mm rings in line with the rectus muscles (3.02 +/- 1.46 D) versus between the muscles (1.37 +/- 1.14 D; p = 0.03), and all measurements with the 14-mm ring (1.0 +/- 1.49 D) versus the 18-mm ring (2.14 +/- 1.51 D; p = 0.04.). CONCLUSIONS: Significant IA can occur with placement of fixation rings, especially when suture placement is near the insertions of the rectus muscles.

Glistenings in the AcrySof intraocular lens: pilot study.

PURPOSE: To evaluate the prevalence, severity, and visual significance of glistenings seen in the AcrySof intraocular lens (IOL) and determine whether a large in-depth study of this lens is warranted. SETTING: John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Patients who had the AcrySof IOL implanted at 1 institution over the past 4 years were serially selected. Forty-two eyes that had phacoemulsification with implantation of the AcrySof IOL were evaluated. The examination consisted of visual acuity, glare, contrast sensitivity, and dilated fundus and dilated slitlamp evaluations. Glistenings in the IOL were graded at the slitlamp from trace to 4+. RESULTS: All 42 IOLs had some degree of lenticular glistenings. The glistenings were graded as trace in 27 IOLs (64%), 1+ in 5 (12%), 2+ in 5 (12%), 3+ in 3 (7%), and 4+ in 2 (5%). The Snellen acuity in eyes with severe glistenings (> or = 2+) was one-half line lower than in eyes with mild glistenings (+) (P =.01). In all eyes, the Brightness Acuity Tester score was a little more than one-half line lower than the Snellen acuity, and the difference was 1 full line in eyes with glistenings graded above 2+. Fourteen of 15 IOLs (93%) with glistenings graded greater than trace had been in the eye for more than 1 year. There was no evidence that contrast sensitivity was affected by the glistenings. CONCLUSIONS: Glistenings occurred frequently in AcrySof IOLs, with most cases mild. A larger study of this lens is needed to determine whether severe presentations affect visual function and to understand how glistenings change over time.

Vacuoles in the Acrysof intraocular lens as factor of the presence of serum in aqueous humor.

OBJECTIVE: Acrysoftrade mark (Alcon) foldable lenses (IOLs) have been shown to be highly biocompatible and exhibit a low incidence of posterior capsular opacification. However, minute vacuoles or 'glistenings' have been observed in some Acrysof IOLs. The clinical relevance of vacuole formation is presently unclear. To help clarify the influence of factors present under in vivo conditions on vacuole formation, the present experimental study examines the influence of aqueous humor components on the occurrence of vacuoles in Acrysof IOLs. METHODS: A total of 12 sterile Acrysof IOLs (Alcon, MA60BM) were incubated at body temperature (37 degrees C) for 3 or 6 months in anterior-chamber aqueous humor with or without human serum. The center portion was cut from two unconditioned, unhydrated, sterile control IOLs and the 12 conditioned IOLs and examined using light microscopy for vacuole formation. A third unconditioned, hydrated control IOL was examined using light and scanning electron microscopy. MEASURES: The incidence of vacuoles was quantified by two independent investigators using light microscopy. After hydration with balanced salt solution, the surface quality of a control IOL was examined using scanning electron microscopy. RESULTS: The control IOLs exhibited no or very few vacuoles. Scanning electron microscopy revealed that the control IOLs had normal surface texture without any surface vacuoles. IOLs that had been conditioned in aqueous humor without serum exhibited no great increase in the number of vacuoles, whereas IOLs conditioned in aqueous humor with serum exhibited a greater number of vacuoles that increased over time. CONCLUSIONS: The number of vacuoles increases with incubation time in aqueous humor containing serum. The addition of serum increased the proportion of lipids and proteins in the solution, which also occurs with a breakdown in the blood-aqueous barrier. The results of the present study point to a physiological factor that may lead to vacuole formation in IOLs and may aid clinicians in identifying risk factors involved in the formation of vacuoles.

Wound complications associated with incision enlargement for foldable intraocular lens implantation during cataract surgery.

PURPOSE: To ascertain whether enlarging the incision for implantation of MA60 intraocular lenses (IOLs) causes increased wound instability and compare the incidence of wound-related complications with that after SI-40NB IOL implantation through an unenlarged incision. METHODS: This retrospective study comprised operative and postoperative notes of consecutive patients who had implantation of an Allergan SI-40NB IOL using the Unfolder or an Alcon MA60 AcrySof IOL from April 30, 1999, and before. The operative reports were used to determine whether there were any wound problems, particularly the need to suture the wound. Records from the first postoperative day were reviewed for evidence of wound leak or other wound-related complications. RESULTS: Of the 200 eyes receiving an SI-40NB IOL, 3 (1.5%) required the placement of a suture during surgery to secure the wound. None had a wound leak 1 day postoperatively. Of the 200 eyes receiving an MA60 IOL, 12 (6.0%) required the placement of a suture during surgery to secure the wound. One eye had a wound leak 1 day postoperatively. The difference in the number of wound-related complications between the 2 IOL groups was significant (P =.01). CONCLUSIONS: Significantly more wound-related complications occurred after incision enlargement for implantation of MA60 IOLs than after implantation of SI-40NB IOLs through unenlarged incisions.

Direct evidence for Mendelian inheritance of the variations in the ribosomal protein gene introns in yellowfin tuna (Thunnus albacares).

Restriction fragment length polymorphism found in the S7 ribosomal protein gene introns of yellowfin tuna (Thunnus albacares) was compared between a single pair of parents and their offspring. The sizes of the first intron ( RP1) and second intron ( RP2) amplified by polymerase chain reaction were 810 bp and 1400 bp, respectively. The dam and sire had different restriction types from one another in HhaI and RsaI digestions for RP1 and in DdeI, HhaI, and ScrFI digestions for RP2. Putative genotypes in both introns of 64 larvae were found to be segregated in Mendelian proportions. Genotype distributions in a wild yellowfin tuna sample ( n = 34) were in Hardy-Weinberg proportions, and observed heterozygosity ranged from 0.149 to 0.388. This study presents novel Mendelian markers, which are feasible for tuna population genetic study and pedigree analysis.

Visual complaints associated with the AcrySof acrylic intraocular lens(1).

PURPOSE: To describe the visual complaints of a series of patients implanted with the AcrySof(R) (Alcon Surgical) acrylic intraocular lens (IOL) that resolved with IOL exchange. SETTING: Jules Stein Eye Institute, Los Angeles, California, and John A. Moran Eye Center, Salt Lake City, Utah, USA. METHODS: This was a retrospective review of patients who had AcrySof IOL exchange from January 1997 to December 1998. RESULTS: Eight patients (9 eyes) with bothersome visual symptoms following AcrySof IOL implantation were identified. Problems included glare, halos around point light sources, and peripheral arcs of light, often worse at night. In each case, the IOL was well-centered in the capsular bag and there was no significant posterior capsule opacification. Six patients (7 eyes) had the MA30BA model with a 5.5 mm optic, and 2 patients (2 eyes) had the MA60BM model with a 6.0 mm optic. No extralenticular reasons for the patients' complaints could be identified. Exchanging the AcrySof IOLs with silicone or poly(methyl methacrylate) IOLs alleviated most symptoms. In 5 of 8 patients, dysphotopsias resolved completely. CONCLUSIONS: A small number of patients implanted with AcrySof IOLs have specific complaints of glare, halos, and peripheral arcs of light. Optical considerations that may help explain these symptoms include the high refractive index of the IOL material and the truncated design of the optic. Patients who are highly observant and those with large pupils may be particularly symptomatic. Intraocular lens exchange may be necessary in some cases.

Penetrating keratoplasty for keratoconus: a long-term review of results and complications.

PURPOSE: To study the long-term complications of penetrating keratoplasty (PKP) to evaluate current recommendations to patients with keratoconus. SETTING: John Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Retrospective study of all PKP procedures for keratoconus performed by 4 surgeons during a 312 year period. Follow-up was 1 day and 1, 3, 6, 12, and 24 months post-PKP. Data from 93 eyes were reviewed for allograft reaction, astigmatism, visual acuity, reasons for decreased visual acuity, and other complications. RESULTS: Allograft reaction was seen in 31% of cases but no graft failure due to allograft reaction. Mean astigmatism was 2.76 diopters (D) +/- 1.99 (SD) at 24 months, with only 15% > 5.00 D. Last best corrected visual acuity was 20/25 or better in 77% of cases (87% had 20/25 or better at some time during follow-up). Complications that did not cause decreased visual acuity were noted. Punctate keratitis was noted in 20% of patients 180 days or more after surgery. CONCLUSIONS: Penetrating keratoplasty is a good treatment option for patients with keratoconus but should be reserved for those who do not tolerate contact lenses or do not get needed visual acuity with contact lenses because of complications. This procedure has become a second-line treatment for keratoconus patients and has generally good results.

Update on a long-term, prospective study of capsulotomy and retinal detachment rates after cataract surgery.

PURPOSE: To evaluate the retinal detachment risks and neodymium:YAG (Nd:YAG) capsulotomy rates associated with different cataract approaches and intraocular lens (IOL) styles in a long-term,prospective clinical study. SETTING: Clinical practice of 1 ophthalmologist, Fort Collins, Colorado, USA. METHODS: Prospectively studied were surgical approach, date, and complications; IOL type; axial length; patient age and sex; Nd:YAG capsulotomy and date; and retinal detachment and date. RESULTS: Phacoemulsification had a lower risk of retinal detachment than intracapsular cataract extraction (ICCE) (0.4% versus 5.4%; P <.001) and extracapsular cataract extraction (ECCE) (0.4% versus 1.6%; P =. 002). Although retinal detachment was significantly associated with Nd:YAG for ECCE (3.1% versus 1.0%; P =.01), no patient in the phacoemulsification group had a retinal detachment after an Nd:YAG treatment. Retinal detachment was strongly associated with axial length of 24.0 mm and greater (P <.001), age of 60 years or less if axial length was 24.0 mm or greater (for ECCE, P =.001; for phacoemulsification, P =.01) and sex; that is, male (for ECCE, P =. 04; for phacoemulsification, P =.02). Regarding IOL styles the Surgidev B20/20 (P <.001) and AcrySof MA60 (P <.001) had significantly lower Nd:YAG rates, while the Cilco UPB 320 GS had a significantly higher Nd:YAG rate (P <.001). CONCLUSIONS: Cataract surgical approach and IOL style significantly affect Nd:YAG and retinal detachment rates. Being a man, being 60 years or younger, and especially having an axial length of 24.0 mm or greater were associated with detachment. Some Nd:YAG approaches may not put the patient at increased risk for retinal detachment.

Dysphotopsia in phakic and pseudophakic patients: incidence and relation to intraocular lens type(2).

PURPOSE: To determine the relationship between various intraocular lens (IOL) types and the incidence of unwanted light images. SETTING: The Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: A telephone questionnaire was administered to 302 postoperative patients who had received 1 of 6 commonly used IOLs between January and September 1998. Patients were included only if they had uneventful cataract surgery, no additional ocular pathology, and a postoperative best corrected visual acuity of 20/25 or better. A control group of 50 patients with the diagnosis of presbyopia only also participated in the questionnaire. Patients reported on incidence of glare, light sensitivity, and unwanted images. The data were analyzed for statistically significant relationships between incidence of photopsias and IOL type. RESULTS: The AcrySof 5.5 mm, AcrySof 6.0 mm, and SI-40 groups reported significantly more unwanted images than the control group (P =.0014). The 2 AcrySof groups also reported a greater incidence of light to the side causing a central flash, and the SI-40 group, a higher incidence of glare. The control group was more likely to experience symptoms of glare than any pseudophakic group. Overall, a mean of 49% of patients reported some light-related phenomenon postoperatively. The majority in all groups reported being satisfied with their eyesight despite the light-related problems. CONCLUSIONS: A significant number of pseudophakic patients reported symptoms of dysphotopsia. Patients who received an acrylic IOL with flattened edges were at increased risk of experiencing images associated with edge reflections. The SI-40 lens group, although less than the AcrySof groups, reported a higher incidence of glare than the non-AcrySof groups; however, it also had the highest number of patients still driving at night. The phakic population commonly experienced glare reported as more severe than several of the IOL groups.

Postoperative sterile endophthalmitis (TASS) associated with the memorylens.

PURPOSE: To report 10 cases of delayed-onset acute intraocular inflammation following cataract extraction and posterior chamber implantation of the MemoryLens(R) intraocular lens (IOL). SETTING: John A. Moran Eye Center, Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA. METHODS: This retrospective study evaluated 10 cases of postoperative inflammation that occurred after cataract extraction with placement of the posterior chamber MemoryLens IOL. Protocols of the Intermountain Ocular Research Center used to analyze outbreaks of unexplained postoperative inflammation as well as medical records were reviewed. RESULTS: Nine patients had uneventful cataract extraction and 1 had a small anterior capsule tear with placement of the MemoryLens IOL. All 10 patients presented with increased anterior segment inflammation a mean of 7.8 days (range 1 to 21 days) after surgery. Three cases were tapped and were culture negative, and 7 were presumed noninfectious. The anterior segment inflammation improved in all patients. Treatment of the 7 patients included intensive topical steroids. Careful analysis of the inflammation has not revealed an obvious etiology; however, the MemoryLens was associated with all the cases. CONCLUSIONS: We postulate that these cases of noninfectious postoperative endophthalmitis may be associated with the MemoryLens.

Protecting the retina during MemoryLens insertion.

BACKGROUND: To determine the light-scattering power of the folded MemoryLens(R). SETTING: Department of Ophthalmology, University of Utah, Salt Lake City, Utah, USA. METHODS: The focusing power of 10 unfolded MemoryLenses (Mentor Ophthalmics) was measured using an optical bench. The IOLs were then unfolded in a 37 degrees C distilled water bath and reexamined within 15 seconds of removal from the bath. Resolutions were read after the lenses were dried for 1 hour and cooled to room temperature and again after they were rehydrated and reheated in the water bath. RESULTS: In the rolled state, all lenses diffused the illumination of the light source. After the IOLs were unfolded in the water bath at 37 degrees C, they gave readings of acceptable to high resolution. After the lenses were air dried for 1 hour and cooled to room temperature, the resolution of all lenses decreased. However, after the IOLs were rehydrated and reheated for 1 more hour, resolution was similar to that of the original hydrated lenses. CONCLUSION: When folded, at a low temperature, or dehydrated, the MemoryLens may provide protection from the operating microscope by scattering light.

Photosynthetic characteristics of marine phytoplankton from pump-during-probe fluorometry of individual cells at sea.

BACKGROUND: Active fluorescence techniques are becoming commonly used to monitor the state of the photosynthetic apparatus in natural populations of phytoplankton, but at present these are bulk water measurements that average all the fluorescent material in each sample. Here we describe two instruments that combine individual-cell "pump-during-probe" (PDP) measurements of chlorophyll (Chl) fluorescence induction, on the time scale of 30 to 100 micros, with flow cytometric or visual characterization of each cell. METHODS: In the PDP flow cytometer, we measure Chl fluorescence yield as a function of time during a 150 micros excitation flash provided by an argon ion laser; each particle is subsequently classified as in a conventional flow cytometer. In the PDP microfluorometer, individual cells in a sample chamber are visually identified, and fluorescence excitation is provided by a blue light-emitting diode that can be configured to provide a saturating flash and also a subsequent series of short flashlets. This sequence allows both saturation and relaxation kinetics to be monitored. RESULTS: Phytoplankton from natural samples and on-deck iron-enrichment incubation experiments in the Southern Ocean were examined with each PDP instrument, providing estimates of the potential quantum yield of photochemistry and the functional absorption cross section for photosystem 2, for either individuals (for cells larger than a few micrometers) or populations (for smaller cells). CONCLUSIONS: Results from initial field applications indicate that single-cell PDP measurements can be a powerful tool for investigating the nutritional state of phytoplankton cells and the regulation of phytoplankton growth in the sea.

Comparison of the effects of viscoelastic agents on clinical properties of the Unfolder lens injection system.

PURPOSE: To evaluate the effect of 7 viscoelastic materials on the physical properties of the Unfolder lens injection system. SETTING: John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, Utah, USA. METHODS: New sterile SI-40NB intraocular lenses (IOLs) were loaded into the Unfolder (AMO PhacoFlex II SofTip insertion system (Allergan) using 7 viscoelastic materials: sodium hyaluronate 1.0% (Healon, Provisc), sodium hyaluronate 1.4% (Healon GV), sodium hyaluronate 1.6% (Amvisc Plus), hydroxypropyl methylcellulose 2.0% (Occucoat), sodium chondroitin 4.0%--sodium hyaluronate 3.0% (Viscoat), and hyaluronate 3.0% (Vitrax). The IOLs were then injected after 10 or 120 seconds in the chamber (chamber dwell time) and 10, 60, or 180 seconds in the barrel of the Unfolder cartridge (barrel dwell time). Torque values (g/cm) required to extrude the lenses were measured with a torque gauge, and the cartridges and IOLs were inspected for damage. RESULTS: Longer chamber dwell times resulted in lower torque values to extrude the IOLs (P < .001). Conversely, longer barrel dwell times resulted in higher torque requirements for IOL extrusion (P < .001). Furthermore, rates of adverse events, such as nondelivery, IOL damage, or Unfolder cartridge damage, were higher with shorter chamber dwell times and longer barrel dwell times (P < .001). However, IOL damage was avoided when the manufacturer's recommended chamber and barrel times were used. CONCLUSION: Increasing chamber dwell time and decreasing barrel dwell time resulted in lower torque values to extrude IOLs from the Unfolder and increased successful use. Moreover, dispersive viscoelastic agents tended to be more forgiving of changing dwell times and therefore had lower torque values and adverse event rates overall.

Cataract surgery complications in 1 year at an academic institution.

PURPOSE: To delineate all complication rates of cataract surgery and define normative rates, trends, and outliers as part of continuous quality management. SETTING: John A. Moran Eye Center, University of Utah Health Sciences Center, Salt Lake City, Utah, USA. METHODS: All cataract surgeries done at the John A. Moran Eye Center from July 1, 1996, to June 30, 1997 (1 complete academic year) were reviewed for intraoperative complications using operative reports. Cases with documented preoperative zonular dehiscence, traumatic capsule breakage, previous vitreous in the anterior chamber, or an accompanying major secondary procedure (e.g., trabeculectomy, corneal transplantation) were eliminated from the study. Over this year, 1729 cataract surgeries were performed by 12 attending physicians, 3 fellows, and 4 residents. Cases of cataract removal with intraocular lens implantation ranged from 18 to 510 per surgeon. RESULTS: There were 44 cases (2.54%) of posterior capsule rupture, with 29 (1.68%) requiring vitrectomy. Most capsule breakages occurred during phacoemulsification. The Student t test showed no statistically significant difference in the incidence of capsule breakage among surgeons (incidence from 0% to 6.25%). All cases were started as phacoemulsification, with 6 conversions (0.35%) to planned extracapsular cataract extraction. CONCLUSIONS: In evaluating continuous quality management, no outliers were found within our center. Phacoemulsification was the part of cataract surgery most likely to cause posterior capsule rupture.