bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of microsatellite loci in red king crab (Paralithodes camtschaticus)
Authors: Seeb L. W. , Kretschmer E. J. , Olsen J. B. , Templin W. D. , Jones K. C. , Grant W. S.
Published: March 2003

Polymerase chain reaction (PCR) primers for three trinucleotide and three tetranucleotide microsatellite loci were developed for red king crab (Paralithodes camtschaticus) to aid in studies of genetic population structure in Alaskan waters. Number of alleles ranged from six to 18 alleles (N = 562), and locus heterozygosities ranged from 0.505 to 0.839. Six primers were cross amplified with golden king crab (Lithodes aequispinus); five primers with blue king crab (P. platypus); and one primer with the splendid hermit crab (Labidochirus splendescens), the ‘missing link’ between pagurid and lithodid crabs. No cross amplification occurred with Tanner crab (Chionoecetes bairdi) or Aleutian hermit crab (Pagurus aleuticus).
Isolation and characterization of 20 polymorphic microsatellite loci for Scaptodrosophila hibisci
Authors: Wilson Alex C. C. , Sunnucks Paul , Barker J. S. F.
Published: March 2003

Scaptodrosophila hibisci
is an endemic Australian Drosophilidae that breeds in the flowers of native
Hibiscus
. Here we report the isolation and amplification of 20 polymorphic microsatellite loci
.
We cloned these microsatellites because loci developed for
Drosophila melanogaster
failed to amplify in
S. hibisci
. Null alleles were detected at six loci, and five were X‐linked. Two of the primer pairs amplified an unlinked ‘bonus’ locus. One locus containing juxtaposed microsatellite loci was suitable for designing an additional set of primers. Mean number of alleles per locus was 10, mean
H
O
and
H
E per locus were 0.532 and 0.636, respectively.
Microsatellite loci for genetic research in the hornet Vespa mandarinia and related species
Authors: Hasegawa Eisuke , Takahashi Jyunichi
Published: March 2003

We developed 5 microsatelitte loci in the hornet Vespa mandarinia from RAPD fragments. The 5 loci showed 3–7 alleles in V. mandarinia and many were also polymorphic in the related species, V. ducalis, V. analis, Dolichovespula norvegicoides and Vespula schrenckii. These results suggested the loci will be useful for analyzing genetic structure of Vespinae, at both the colony and population levels.
Isolation of microsatellite loci in spotted salamanders (Ambystoma maculatum)
Authors: Wieczorek A. M. , Zamudio K. R. , King T. L. , Gjetvaj B.
Published: March 2003

To assess the level and spatial pattern of genetic diversity in the spotted salamander, Ambystoma maculatum, we characterized hypervariable molecular markers by screening genomic libraries enriched for microsatellite motifs. We designed primers that reliably amplify twelve polymorphic loci and checked for variability in individuals from populations in the vicinity of Ithaca, New York. Loci show high variability in the number of alleles and heterozygosities, suggesting they will be useful for determining local population differentiation and mating systems in this pond‐breeding amphibian.
Microsatellite loci from the pink shrimp Farfantenaeus notialis (Crustacea, Decapoda)
Authors: Robainas A. , Monnerot M. , Solignac M. , Dennebouy N. , Espinosa G. , García‐Machado E.
Published: March 2003

Farfantepenaeus notialis is an important resource for fisheries in Cuba. For this reason and for a sustainable exploitation it is important to study their population structure and genetic variability. We report and characterize microsatellites as genetic markers from this species. Fifteen microsatellite polymerase chain reaction (PCR) primers were designed and tested in some individuals from different populations. Seven pair of primers showed reliable amplification products and five were polymorphic. The allele number ranged from 4 to 33, and the observed and expected heterozygosities were relatively high with values between 0.63 and 0.74 and 0.56 and 0.81, respectively. Departures from Hardy–Weinberg equilibrium were observed for all loci.
Novel primer sets for species‐specific amplification of the mitochondrial 12S rRNA genes in four Japanese woodpeckers (Picidae, Piciformes)
Authors: Nakamura Mitsuhiro , Ishibashi Yasuyuki , Syuiti Abe
Published: March 2003

In birds, feathers and faeces can be used as a source of DNA for genetic analyses. If the materials are derived from an absentee bird(s), however, the species must first be identified. Here, we developed four pairs of primers for amplification of mitochondrial 12S ribosomal RNA fragments in the black woodpecker Dryocopus martius, a vulnerable species in Japan, and three other sympatric woodpeckers including Dendrocopos leucotos, D. major and Picus awokera. Because each primer pair gave a PCR product in only one of the examined species, these primer sets will be useful in identifying the species of woodpeckers.
Isolation and characterization of polymorphic microsatellites in the tropical plant‐ant Cataulacus mckeyi (Formicidae: Myrmicinae)
Authors: Debout G. , Dalecky A. , Mondor G. , Estoup A. , Rasplus J.‐Y.
Published: March 2003

Eleven microsatellite loci were isolated from the plant‐ant Cataulacus mckeyi (Hymenoptera: Myrmicinae) and their polymorphism was characterized. High levels of within‐population variation were observed at most loci, with number of alleles ranging from one to 16, and heterozygosity from 0 to 0.929 per population sample. Cross‐species amplification of these loci was also tested in four other species of the ant genus Cataulacus.
Molecular sex identification of tinamous with PCR using primers derived from the spindlin gene
Authors: De Kloet Siwo R.
Published: March 2003

This paper describes results which show that the spindlin gene has different forms on the tinamid W and Z chromosome, providing a sensitive and accurate procedure for a molecular, polymerase chain reaction‐based procedure for sex identification of tinamous.
spagedi: a versatile computer program to analyse spatial genetic structure at the individual or population levels
Authors: Hardy Olivier J. , Vekemans Xavier
Published: March 2003

spag
e
d
i version 1.0 is a software primarily designed to characterize the spatial genetic structure of mapped individuals or populations using genotype data of codominant markers. It computes various statistics describing genetic relatedness or differentiation between individuals or populations by pairwise comparisons and tests their significance by appropriate numerical resampling.
spag
e
d i is useful for: (i) detecting isolation by distance within or among populations and estimating gene dispersal parameters; (ii) assessing genetic relatedness between individuals and its actual variance, a parameter of interest for marker based inferences of quantitative inheritance; (iii) assessing genetic differentiation among populations, including the case of haploids or autopolyploids.
Microsatellite loci for studies of population differentiation and range expansion in Solidago sempervirens L. (Asteraceae)
Authors: Wieczorek A. M. , Geber M. A.
Published: March 2003

For studies of population differentiation and range expansion in the seaside goldenrod, Solidago sempervirens, we identified hypervariable molecular markers by screening genomic libraries enriched for microsatellite motifs. We designed primers that reliably amplified nine polymorphic loci. High polymorphism in a population from Delaware Bay, USA suggests that the loci will be useful in population studies. The success of cross‐amplifications in 11 species of Asteraceae varied among loci and did not appear to reflect phylogenetic relationships within Solidago.
Isolation and characterization of microsatellite loci from the forage species Arachis pintoi (Genus Arachis)
Authors: Palmieri D. A. , Hoshino A. A. , Bravo J. P. , Lopes C. R. , Gimenes M. A.
Published: March 2003

Arachis pintoi
is an alternative to forage production in the tropics. Its germplasm comprises more than 150 accessions, that could be used to improve it. Our objective was the isolation and characterization of microsatellite loci in
A. pintoi
to be used to molecular evaluation of this germplasm and of
A. repens
(section
Caulorrhizae
). Seven loci were analyzed using five accessions of
A. repens
and 20 accessions of
A. pintoi
. The high variation found makes clear the high potential of this marker in genetic studies in these species. The developed markers showed total transferability to
A. repens .
A5. Psychopathological screening: psychopathological evaluation instruments in aesthetic surgery
Authors: Gotti M , Borghetti G
Published: March 2003

Incidences of psychiatric disorders are higher among patients who undergo plastic surgery than they are among patients undergoing other types of surgery. This literature makes reference to those pathologies consisting of a denial of one's own body or part(s) of it. Among the pathologies considered the most widespread is physical dysmorphophobia.

Studies have shown that clients afflicted by this pathology can deteriorate even following aesthetic surgery. These procedures, even though correctly performed, do not give the expected results and the patients are unsatisfied. Commonly, these patients experience the onset of new concerns which may worsen their clinical portfolio. Further postoperative deterioration may lead to legal implications. The law asserts the inviolability of the individual even though he/she may suffer from latent psychological disorders. The perturbation of mental equilibrium, even though labile, represents a refundable damage. Law, as well as surgery, asserts the importance of psychological wellbeing. Clinical evaluation instruments are presently employed in America as well as in Italy.
A7. Non‐invasive skin rejuvenation techniques
Authors: Karam Paula
Published: March 2003

Skin ageing manifests itself as loss of lustre and elasticity, irregular pigmentation and wrinkling ranging from fine to deep. Most of these changes can be reversed and, depending on the procedures used, the results last from few months to several years.

A baseline for all types of treatment of skin ageing is the use of anti‐ageing gels or creams. These consist of the daily application of vitamin C, fruit acid, vitamin A acid and depigmenting agents. This type of treatment will bring a youthful appearance to the whole skin and reduces blemishes and fine wrinkles. Often we need to combine one or more of the cosmetic procedures available to achieve a more pronounced result. Superficial wrinkles are best treated by superficial or medium‐depth peels, while deeper wrinkles indicate the use of laser skin resurfacing. Other methods to correct fine and deep wrinkles include fillers, ranging from hyaluronic acid to collagen, silicone and fat, botulinum and others.

In conclusion, to achieve the best results we often need to combine two or many of the above procedures, keeping in mind that certain patients should be advised to have a face lift in conjunction with these treatments.
A8. Time‐related macro‐ and microanatomical modifications observed in vascular malformations: signs of relentless, uncontrollable evolution?
Authors: Kiryu Hiromaro
Published: March 2003

Cutaneous haemangiomas can be a cosmetic problem mainly because of their colour and due to any secondarily‐associated lesions which the patient feels to be unattractive.

Strawberry marks and portwine stains are common malformations and it is recommended that they are treated by laser as early as possible. Strawberry marks usually appear shortly after birth and develop for a short while before shrinking. The subsequently damaged skin, however, may have a rough and wrinkled appearance which sometimes needs surgical correction.

Portwine stains are usually present at birth.1 The lesion does not diminish and the colour darkens later. Some nodules, named hypertrophic portwine stains, will appear later in life within the macular lesions and also need to be treated surgically.
The Koebner phenomenon: review of the literature
Authors: Weiss G , Shemer A , Trau H
Published: March 2003

First described in 1877 as the appearance of psoriatic lesions in the uninvolved skin of psoriatic patients as a consequence of trauma, the Koebner phenomenon has since been described in numerous diseases. Other authors have tried to implicate either infections or parasitic causes as the pathogenesis of this phenomenon. Subsequent research by many authors have contributed to our poor understanding of this reaction in the hope of understanding the pathogenesis of psoriasis. We present a review of the literature covering the following topics as they relate to the Koebner phenomenon: diseases that koebnerize and their possible causes, predisposing and provoking factors, type, site, depth and degree of trauma, the all or none phenomenon, time lag, site preference, medications, inhibition of koebnerization and reverse koebnerization.
Accident and emergency medicine specialist registrars’ perceptions of the ‘essential’ aspects of a training placement
Authors: Stewart Jane , Bregazzi Richard , O'Halloran Catherine
Published: March 2003

This study set out to identify the important aspects of training placements as perceived by specialist registrars (SpRs) in accident and emergency medicine (A&EM). These data were to be used to gain greater insight into the collective wishes of this group in order to inform the development of quality assurance systems. A self‐administered questionnaire was developed from repertory grid data and was used to identify what were the ‘essential’, ‘useful’ and ‘not needed’ aspects of A&EM training placements. The questionnaire covered ‘the job’, ‘the department’, ‘clinical experiences’, ‘support for learning’ and ‘training’. SpRs were also asked how frequently they wished certain activities to take place. The questionnaire was completed by 16 of the 17 A&EM SpRs (94%) training in the Northern Deanery. Of the 82 statements submitted to the SpRs, 40% (33) were marked as ‘essential’ by 75% or more of the registrars. Aspects classed as ‘essential’ by the highest number of SpRs were concerned with the recognition of their role as learners within a service environment and with how their learning was supported. SpRs felt it was essential to be integrated into the work team with a clear role that was understood to combine ‘education’ and service provision. Although there was consensus, the findings also showed the SpRs’ individuality in terms of their learning and support needs. The study illustrates the complexity of defining quality indicators for evaluating training processes in work placements and suggests that quality lies not just in the components of a system for managing education but also in the flexibility of its application and in aspects of the ‘learning culture’.
Sensitivity of breeding parameters to food supply in Black‐legged Kittiwakes Rissa tridactyla
Authors: Gill Verena A. , Hatch Scott A. , Lanctot Richard B.
Published: March 2003

We fed Herring Clupea pallasi to pairs of Black‐legged Kittiwakes Rissa tridactyla throughout the breeding season in two years at a colony in the northern Gulf of Alaska. We measured responses to supplemental feeding in a wide array of breeding parameters to gauge their relative sensitivity to food supply, and thus their potential as indicators of natural foraging conditions. Conventional measures of success (hatching, fledging and overall productivity) were more effective as indicators of food supply than behavioural attributes such as courtship feeding, chick provisioning rates and sibling aggression. However, behaviour such as nest relief during incubation and adult attendance with older chicks were also highly responsive to supplemental food and may be useful for monitoring environmental conditions in studies of shorter duration. On average, the chick‐rearing stage contained more sensitive indicators of food availability than prelaying or incubation stages. Overall, rates of hatching and fledging success, and the mean duration of incubation shifts were the most food‐sensitive parameters studied.
Extrapair paternity in the HoopoeUpupa epops: an exploration of the influence of interactions between breeding pairs, non‐pair males and strophe length
Authors: Martín‐Vivaldi Manuel , Martínez Juan Gabriel , Palomino José Javier , Soler Manuel
Published: March 2003

Previous studies of the HoopoeUpupa epopshave shown that the strophe length of male songs influences female mate choice, and is correlated with female reproductive rates and male production of fledglings in the male’s own brood. However, frequent interactions between breeding pairs and non‐pair males suggests that extrapair copulations could occur and could affect the real number of fledglings sired by males, and therefore the relationship between strophe length and breeding success. Here we analyse the incidence of interactions between breeding pairs and non‐pair males, and of extrapair paternity, the interrelation of these parameters, the influence of male strophe length on them, and whether extrapair fertilizations affect the correlation between strophe length and breeding success of males, in a colour‐ringed population of Hoopoes in south‐eastern Spain. Multilocus DNA‐fingerprinting revealed that 10% of the broods contained offspring sired by extrapair males, representing 7.7% of the chicks. However, the interactions between pairs and non‐pair males were more frequent, with more than 25% of broods being visited by non‐pair males, and about 10% being helped (fed or defended) by males other than the nest owner. Most of these relationships were apparently attempts by visitor males to obtain copulations with paired females, or to obtain access to such females or nests in future breeding attempts. However, there was no significant link between the detection of interactions with alien males in a nest and the occurrence of extrapair paternity in it, indeed extrapair paternity was found in only 30% of the nests with interactions, and therefore the detection of visits or helping by non‐pair males cannot be considered evidence of extrapair paternity in visited or helped broods. Males that sang with long strophes never suffered losses of paternity within their broods, while 25% of males that sang with short strophes did. However, these differences were not significant. Nevertheless, strophe length of males was significantly positively correlated with per brood and seasonal production of fledglings after accounting for losses of paternity within their own broods.
A comparison of infestation patterns byIxodesticks in urban and rural populations of the Common BlackbirdTurdus merula
Authors: Gregoire Arnaud , Faivre Bruno , Heeb Philipp , Cezilly Frank
Published: March 2003

Although spatial variation in the patterns of parasite infestations among host populations may have important ecological and epidemiological consequences, the causes underlying such variation are poorly known. In the context of a long‐term study on the population biology of Common BlackbirdsTurdus merula, we examined the prevalence and intensity of infestation byIxodesticks between birds living in rural vs. urban habitats. The overall prevalence of tick infestations was significantly higher in the rural habitat where 74% of individuals (n = 130) were infested. This result contrasted markedly with the situation in the urban habitat where less than 2% of individuals (n = 360) carried ticks. There was no significant effect of the sex of the host on the intensity or prevalence of tick infestations. There was a significant effect of the age of the host on tick infestations essentially due to the absence of ticks on nestlings. Possible mechanisms responsible for the differences between habitats could include differences in tick survival and/or host resistance towards ticks. Previous studies have shown higher population densities and suggested longer survival for Blackbirds in urban than in rural habitats. Given that ixodid ticks are known to transmit pathogens likeBorreliaspp. to wild birds, and that Blackbirds can act as reservoirs for these pathogens, the infection patterns observed in our study area provide a suitable situation to study the interrelations between ticks, Blackbirds and pathogens.
Genetic and morphological differentiation between remnant populations of an endangered species: the case of the Seychelles White‐eye
Authors: Rocamora Gérard J. , Richardson David S.
Published: March 2003

The Seychelles White‐eyeZosterops modestusis a critically endangered species that survives in two remnant populations on the islands of Mahé and Conception. Multilocus minisatellite DNA fingerprinting and morphometric measurements were used to assess the levels of variation between these populations. Mahé White‐eyes are on average significantly larger than Conception birds, as are males compared to females. The mean level of bandsharing (c. 60%) indicates low levels of genetic variability within both populations. Bandsharing is significantly lower between populations (32%), suggesting that the two populations are genetically isolated from each other, and that one is not a subsample from the other. Both populations should therefore be considered as equally important genetic reservoirs that deserve to be safeguarded. Although each population appears locally adapted to its particular island environment, such limited differentiation is not considered of major taxonomic significance. Recombining genetic variation by mixing individuals from both populations may be beneficial for the species in view of future island transfers. This illustrates the importance of investigating differentiation between remnant populations of a threatened species to orientate future conservation and management measures.
Mate choice in Pied Flycatchers Ficedula hypoleuca: can females use song to find high‐quality males and territories?
Authors: Lampe Helene M. , Espmark Yngve O.
Published: March 2003

High‐quality male Pied Flycatchers Ficedula hypoleuca (defined by brighter plumage, better condition and more experience) have previously been shown to have larger syllable repertoires and greater song versatility than males of inferior quality. Thus, by preferring more complex songs, females could choose a high‐quality male. Females may also use song as a cue to find a high‐quality territory since early arriving males may obtain the best territories and these males have more complex songs than late‐arriving males. We found that males with more complex songs had a greater chance of becoming paired and stayed unpaired for a shorter period than males with less elaborate songs. When controlling for arrival order, however, only strophe versatility was still correlated with pairing order. Males defending popular territories had more complex and longer songs and were also in better body condition than males in less popular territories. A multiple logistic regression showed that song length was important in explaining whether a male defended a popular nestbox or not. Thus, male arrival time seems to be important in deciding the quality of a male's territory, which in turn explains female choice. However, song quality seems to add important information. Thus, females could find both high‐quality males and high‐quality territories by using song cues during mate choice.
Chart construction and letter legibility/readability
Authors: McMonnies Charles W.
Published: March 2003

Variation in legibility/readability between charts letters may be due to differences in chart construction and/or examination protocols and/or subject selection. An examination of legibility/readability of letters that are common to two chart constructions was undertaken. Identical examination and subject selection protocols for both charts were employed. It was found that ranking of error frequencies for some letters varied between the Bausch & Lomb Compact Acuity Projector and Bailey–Lovie charts. Despite many similarities in ranking, the differences found for the letters D and E indicate that caution should be observed before assuming that legibility/readability determined with one letter chart would apply when using another. Lack of standardisation for chart construction, as well as measurement methods and conditions of measurement, invalidate inter‐practice comparisons for visual acuity.
Influence of chronic alcohol abuse and ensuing forced abstinence on static subjective accommodation function in humans
Authors: Campbell Hugh , Doughty Michael J. , Heron Gordon , Ackerley Roger G.
Published: March 2003

Purpose. Acute alcohol ingestion can change accommodation, but the long term effects of sustained alcohol consumption on accommodative function have not been studied in detail. This study was thus undertaken on individuals with a history of alcohol abuse.

Methods. Thirty‐seven male individuals aged 25–56 years (average 40 years) from an alcohol rehabilitation centre in Inverness, Scotland, were assessed on admission and after a week of forced abstinence. The results were compared to a paired age‐matched set of control male subjects. The static amplitude of accommodation was measured by an RAF rule, and the pupil size measured with a pupil gauge.

Results.
On admission, the group mean measured amplitude of accommodation was 4.7±2.2 D (mean±SD). These values for the alcoholics were lower than age‐matched controls (of5.9±2.9 D). The slope of the age‐dependent decline in RAF rule accommodation measures was significantly smaller for the alcoholics compared to controls (at 0.215±0.027 D/year versus0.332±0.015 D/year, respectively;
p <0.001), with the younger alcoholics showing a greater impairment. Following abstinence, there was no measurable change in accommodation measured, indicating the lower amplitude in the alcoholics was not attributable to circulatory alcohol levels. The resting pupil diameter in the alcoholics was4.37±0.63 mm compared to the controls of3.97±0.75 mm, with a higher incidence of small pupils (≤3 mm) in the controls.

Conclusions. The results indicate that chronic alcohol use can adversely affect subjective static accommodation, especially in younger alcoholics, as well as cause slight mydriasis.
The ChromaGen contact lens system: colour vision test results and subjective responses
Authors: Swarbrick Helen A. , Nguyen Phuong , Nguyen Tuyen , Pham Phuong
Published: March 2003

The ChromaGen lens system is designed to enhance colour perception in colour vision deficiency (CVD). To investigate its efficacy, 14 CVD subjects were prescribed ChromaGen contact lenses. Colour vision tests (Ishihara, Farnsworth Munsell D‐15, Farnsworth Lantern) were administered at baseline, lens dispensing, and after a 2‐week lens‐wearing trial during which subjective responses were recorded daily using visual analogue scales. ChromaGen lenses significantly reduced Ishihara error rates(p<0.001; ANOVA), particularly for deutan subjects. There was also a significant reduction in errors(p<0.005) on the D‐15 test. Conversely, lens wear had no significant effect on Farnsworth Lantern test performance. Subjectively, subjects reported enhanced colour perception, but poor vision in dim light. Judgement of distance and motion were only slightly affected. We conclude that ChromaGen lenses may enhance subjective colour experience and assist in certain colour‐related tasks, but are not indicated as an aid for CVD in occupations with colour vision‐related restrictions.
Optimal reading speed in simulated cataract: development of a potential vision test
Authors: Patel Bhavesh , Elliott David B. , Whitaker David
Published: March 2003

Previous studies suggest that optimal reading speed is unaffected by cataract, yet is significantly reduced in age‐related macular disease. This raises the question of whether a reading speed test could be developed to assess potential vision after cataract surgery. In this study, 20 young subjects, with and without a simulation of dense cataract, read aloud Bailey‐Lovie word charts. From the results, critical print size, optimal reading speed and word acuity were calculated. The simulated cataract reduced word acuity and increased the critical print size, yet optimal reading speed remained unchanged. Measurements were also taken with the charts in reversed contrast polarity. Reversing the contrast polarity of the charts improved the word acuity and optimal reading speed with the cataract simulation. The results suggest that optimal reading speed could be used as a potential vision test. Further investigations using patients with cataract and ARMD are required.
Peripheral astigmatism in emmetropic eyes
Authors: Gustafsson Jörgen , Terenius Erik , Buchheister Jan , Unsbo Peter
Published: March 2003

The long‐term aim of the work introduced here is to investigate the influence of off‐axis aberrations on human vision, especially for subjects with a large central scotoma. The latter use their peripheral vision in spite of its poor off‐axis optical quality, and a correction of the off‐axis aberrations might be of great assistance. The eccentric fixation angles used by these subjects can be up to 20–30°. In this initial study we have measured oblique astigmatism, the major off‐axis aberration, in 20 emmetropic eyes in 10° steps out to 60° nasally and temporally using a ‘double pass’ setup. The results show very large individual differences and the oblique astigmatism also varies from nasal to temporal side. In an off‐axis measurement angle of 30° the astigmatism varied between subjects from 1 to 7‐D, with a mean astigmatism of about 4‐D on the nasal side and about 1.5‐D lower on the temporal side. At 60° temporally, the mean astigmatism was 7‐D. At 60° nasally, all subjects had astigmatism larger than 8‐D and the mean astigmatism was 11‐D. The results indicate that any attempt to correct the off axis astigmatism in an eye with central scotoma cannot be based on central refraction; instead, individual measurements are necessary.
Diagnosis of eccentric fixation using a calibrated ophthalmoscope: defining clinically significant limits
Authors: Cleary M. , Thompson C.M.
Published: March 2003

Visuscopy and other ophthalmoscopic methods are widely applied in the assessment of fixation behaviour in amblyopia, although the reliability and inter‐examiner variability of this test has not been established. Typically eccentric fixation is diagnosed solely on the basis of retinal position, but this fails to address the accompanying sensorimotor adaptations. A double‐blind (masked) trial of a paediatric population was undertaken (n=30, age range 3 years 9 months to 11 years, mean 5.6±1.5 years), involving three examiners applying a detailed protocol. The criteria for eccentric fixation were established from the non‐amblyopic eyes. The most reliable criterion for the diagnosis of fixation was established from the results of the study. No single parameter proved 100% reliable, and amplitude showed greatest inconsistencies. It is recommended that a consensus of at least three parameters from position, zero retinomotor point, principal visual direction and percent foveation is required to diagnose the fixation status reliably.
A multiple regression approach to study optical components of myopia in Singapore school children
Authors: Tong Louis , Wong Ee Hwee , Chan Yiong Huak , Balakrishnan Vivian
Published: March 2003

Purpose: Previous studies on the optical components of childhood myopia adjusted only for age and gender or reported only the change of individual components with time. We perform a study to assess the association of the optical components of the eye contributing to the degree of myopia by building a statistical model which can better assess the individual effects of each optical component.

Methods: Children 6–12 years old with myopia of −1 to −6 D were used in this study. Autokeratometry was performed to determine the mean corneal power in two perpendicular meridia. Ultrasonography was used to determine the vitreous chamber depth (VCD). Ultrasonography and Scheimflug biometry were used to determine lens thickness (LT) and anterior chamber depth. A stepwise multiple linear regression was used to determine statistically significant independent variables that explain the variation in the mean spherical equivalent of the left eye. The independent variables investigated were anterior chamber length, LT, VCD, mean corneal power, age and gender. The first regression model used measurements of anterior chamber depth and LT from ultrasonography, while the second model used measurements from Scheimflug photography. Statistical significance was set atp < 0.05.

Results: Both statistical models have the same significant independent variables – VCD, LT and gender, with similar estimates. In both models, VCD was found to have the strongest partial association with mean spherical equivalent, followed by gender and LT. A more myopic refractive error was associated with (1) a longer eye, (2) an increased LT, and (3) female gender.

Conclusions: Myopia was associated with a longer vitreous chamber. This remained the primary determinant of myopia in Chinese children after consideration of other optical components. The effect of gender and LT on myopia requires further study. These results are in agreement with multiple regression analyses in Singapore adults.
Diffraction haloes resulting from corneal oedema and epithelial cell size
Authors: Caldicott Anna , Charman W. Neil
Published: March 2003

Corneal oedema was induced by exposing the corneas of nine subjects, covering an age range from 20 to 64 years, to distilled water for approximately 25 min. Measurement of the diameters of the associated diffraction haloes observed around a small 633 nm source allowed the size of the diffracting elements within each cornea to be estimated as about 10 μm, in good agreement with direct measurements by in vivo confocal microscopy of the subject's basal epithelial cells.
Optimal green (red‐free) digital imaging of conjunctival vasculature
Authors: Owen Christopher G. , Ellis Timothy J. , Rudnicka Alicja R. , Woodward E. Geoffrey
Published: March 2003

Aims/background: Green illumination is commonly used to image vessels of the retina and conjunctiva. The purpose was to derive the best optical set‐up for imaging vessels of the conjunctiva.

Methods: The concept of exposure density was used to predict a digital camera response to imaging vessels on a scleral background. Practical verification was performed to verify vessel contrast because of the difficulties in measuring the spectral components of the imaging system, such as the spectral reflectivity of vessels and sclera. Images of the same conjunctiva were repetitively taken through different coloured filters, using the Nikon FS‐2 photo slit‐lamp and recorded on different coloured channels of the Kodak DCS 100 digital camera. Gaussian blurred tubular models were fitted to densitometric profiles across three vessels from each image, allowing vessel contrast and width to be objectively measured. These measures were compared using different optical set‐ups.

Results: Optimal exposure density calculations and vessel contrast was obtained with the xenon light source filtered with Wratten 99 (green) and Wratten 96 (neutral density, 0.2 log units) gelatine absorption filters using the green channel of the digital camera. This image set‐up was associated with a 46% (99% CI 43–51%) to 64% (99% CI 58–72%) increase in contrast compared with vessels imaged without filtration, using the combined colour channel of the digital camera. Although differences in vessel widths resulted, absolute differences were marginal.

Conclusion: With the increased use of digital imaging, and the need for image processing of vascular networks, image optimisation is beneficial. This study verified the optimal set‐up for non‐invasively imaging vessels of the bulbar conjunctiva.
An assessment of the orthogonal astigmatism test for the subjective measurement of astigmatism
Authors: Murphy Paul J. , Beck Alan J. , Coll Eunan P.
Published: March 2003

The orthogonal astigmatism test (OAT) is a newly developed method for assessing ocular astigmatism. This study compares the OAT with the Jackson crossed‐cylinder (JCC), Raubitschek arrow (RA) and the fan and block (FB) (fan chart). Fifty emmetropes or corrected spherical ametropes (<0.25 DC of astigmatism) were recruited, with a visual acuity of at least 6/5 in both eyes. Pseudo‐astigmatism was induced by placing a +0.75 DC lens in front of the right eye at a random axis. With the left eye occluded, each subjective test was performed in a random order and the correcting lens power and axis noted. No significant difference was found in the ability of the OAT to locate the power and axis of the induced astigmatism over the JCC, RA and FB. In conclusion, the OAT offers the clinician an alternative method for locating and correcting ocular astigmatism. It has a similar but not superior accuracy to the other three subjective tests assessed.
Benefit of coloured lenses for age‐related macular degeneration
Authors: Wolffsohn J. S. , Dinardo C. , Vingrys A. J.
Published: March 2003

Purpose: To evaluate and compare the functional and perceived benefits of wearing coloured lenses by patients with age‐related macular degeneration (ARMD).

Method: Ten subjects with early ARMD and five elderly controls wore a selection of NoIR wrap‐around coloured lenses (yellow 29.7% light transmission, orange 22.9%, red 16.8% and grey 10.3%), each for a duration of 7 days. Contrast sensitivity, colour vision, visual acuity, the effect of glare and peripheral sensitivity were measured for each lens and compared with a control (no lens) condition. Subjective ratings of visual performance were also scored.

Results: Compared with the no filter condition, red and grey lenses reduced contrast sensitivity whereas yellow and orange lenses increased contrast sensitivity. These objective changes were supported by subjective ratings in subjects with ARMD. Grey lenses reduced the loss of contrast sensitivity usually suffered in the presence of glare, whereas visual acuity and peripheral sensitivity decreased with red lenses. Colour vision became distorted with red lenses in control subjects, but was relatively unaffected by the use of coloured lenses in subjects with ARMD.

Conclusions: The subjective benefit of coloured lenses appears to be due to a minor enhancement of contrast sensitivity.
Information within optometric practice: comprehension, preferences and implications
Authors: Fylan Fiona , Grunfeld Elizabeth A.
Published: March 2003

The partnership approach to health care, in which patients take an active role in decision making, can potentially improve patient satisfaction and adherence to clinician recommendations. However, the process can be impeded by insufficient or poor‐quality information provision. This study explored participants' understanding of, and requirements for, optometric information. Information leaflets were obtained from 12 optometry practices and four internet‐based resources. Sixty‐four patients/clients participated in focus groups that explored: (1) their understanding of diagrams of visual function, (2) perceptions of good information, (3) information requirements and (4) perceptions of the effects of improved information. A theory‐led thematic analysis identified three major themes within each of the four categories. The use of jargon and the inappropriate layout of diagrams and text impeded comprehension of the leaflets. High‐quality information was defined as being written concisely with simple explanations and clear diagrams. There was also a preference for information to be relevant and applicable to the patient's own eye care needs. In addition, participants expressed a desire for both written and verbal information regarding eye examination procedures and interpretation of prescriptions. Advice regarding eye care was also requested. To facilitate a partnership approach and improve patient satisfaction, patients should be provided with jargon‐free concisely written and clearly presented information. In addition to general information, patients would also benefit from personalised information regarding test results and eyecare regimes.
Ocular optics, electroretinography and primary open angle glaucoma
Authors: Drasdo Neville , Aldebasi Yousef H. , Mortlock Katharine E. , Chiti Zohreh , Morgan James E. , North Rachel V. , Wild John M.
Published: March 2003

Abstract Advancing the knowledge of ocular image quality is important in the development of new tests for the earlier detection of primary open angle glaucoma (POAG). Loss of blue sensitivity is an important feature of POAG; however, it is difficult to separate this loss from the effects of wavelength related intraocular light scatter and media absorption. A technique for recording the S‐cone electroretinogram is described which may solve these problems. The effect of scattered light is avoided by a Ganzfeld stimulus and the absorption of short wavelength light is compensated by a photometric balancing of blue and green stimuli using the M‐cone response. The modulation transfer function of the eye has enabled the true spatial tuning function of the retina to be determined by pattern electroretinography (PERG). This has demonstrated the role of retinal ganglion cells in the generation of the PERG. These techniques are shown to be highly sensitive tests in the early stages of POAG.
Steady‐state VEP and behavioural measures of visual acuity in infants and children with Down syndrome
Authors: John Ff. M. , Bromham N. R. , Candy T. R. , Woodhouse J. M.
Published: March 2003

Purpose:  Children with Down syndrome (DS) have reduced behavioural visual acuity (VA). This may reflect sensory deficits, or alternatively, a loss of performance in later mechanisms responsible for behavioural responses. This study compared acuity measured using visual‐evoked potentials (VEP), with behavioural tests, in children with DS. The goal was to determine whether reduced VA could be detected in VEP recordings from the first stages of the response pathway.

Methods:  The subject group contained 34 children with DS and 35 controls, aged 3 months to 14 years. VA was measured using steady‐state, swept VEP (Norcia and Tyler, 1985). VA was also measured using behavioural techniques.

Results:  Visual acuity was analysed using a subject group (DS vs controls) × test type (behavioural vs VEP) anova with age as a covariate. A significant effect of subject group was observed (F1,59 = 8.632, p < 0.001) and a significant interaction between subject group and test type (F1,59 = 5.169, p = 0.027). The DS group showed reduced VA compared with the controls in both VEP and behavioural tests, but the deficit was more pronounced with behavioural testing. Reduced VA in the DS group was still seen when analysis was restricted to children who accommodate accurately (F1,26 = 8.047, p = 0.009).

Conclusions:  Reduced VEP acuity in the DS group supports the idea of an underlying sensory deficit in the DS visual system. Increased reduction with behavioural techniques implies additional losses at later stages of processing. Accommodative inaccuracy does not fully explain reduced VA in DS. Children with DS who do not have significant levels of defocus still exhibit reduced VA when compared with controls.
Distribution of rod bipolar cells in the retina of the albino rat
Authors: Davda P. , Dovey M. , Jeffery G. , Baker G.
Published: March 2003

Purpose:  In the retina of albino mammals so far examined there is a deficit in the rod photoreceptor population. We reasoned that a consequence of the rod deficit might be a subsequent abnormality in the next level of the rod pathway, the rod bipolar cell. We therefore compared the distribution of rod bipolar cells in pigmented and albino rats.

Methods:  Rod bipolar cells were labelled in 15 µm thick sections of fixed retinas with a monoclonal antibody directed against protein kinase C, and visualized using the ABC method. Counts of the cell bodies and processes of rod bipolar cells were undertaken at various locations across the retina.

Results:  Qualitatively, the protein kinase C staining suggested differences between the albino and pigmented phenotypes both in the outer and inner plexiform layers and in the inner nuclear layer. Staining was denser in the pigmented retina and the bipolar cell bodies were arranged in multiple rows rather than a single row as found in the albino retina. The actual number of rod bipolar cells was reduced in the albino phenotype. At the neonatal age we examined (post‐natal day 15), there was a 14% reduction in the total number whereas in the adult retina the reduction was around 9%.

Conclusions:  Although the reduction in the rod bipolar population is not as great as that previously found for the rod photoreceptors (∼25%), the reduction in both populations suggests a general abnormality in the rod pathway of albinos. Further, our data support the view that melanin is crucially involved in the normal development of retinal structure.
Postural stability changes in elderly subjects due to disruption of the somatosensory and vestibular system inputs, refractive blur and dual tasking
Authors: Anand V. , Elliott D. B.
Published: March 2003

Purpose:  To determine the effect of disruption of the inputs from the somatosensory and vestibular systems, refractive blur and dual tasking on postural stability in healthy, elderly subjects.

Methods:  Fifteen healthy, elderly subjects (mean age 71 ± 5 years, binocular VA −0.07 ± 0.05 logMAR, Snellen 20/17) with no history of falls and normal vision were recruited. Postural stability during standing was assessed using an AMTI force plate, and was determined as the Root Mean Square (RMS) of the Centre of Pressure (COP) signal in the anterior–posterior (AP) and medial–lateral (ML) directions collected over 30 s periods. Data were collected under normal standing conditions and when the inputs from the somatosensory and vestibular systems were disrupted. Measurements were also repeated with the subject being given an additional physical task (holding a tray of cups) and/or mental task (counting backwards). For all measurement conditions, postural sway was measured under conditions of binocular refractive blur of 0,1, 2, 4 and 8 D and with eyes closed. The data were analysed using a population‐averaged linear model.

Results:  All factors except the additional physical task significantly decreased postural stability (p < 0.001). The greatest decreases in postural stability were because of disruption of the somatosensory system (95% AP increase) and disruption of both the somatosensory and vestibular systems (152% AP increase). Increasing refractive blur caused decreasing postural stability, with 8 D blur causing a 44% increase in AP RMS COP under normal standing conditions. The effect of refractive blur was greater when the input from the other sensory systems was disrupted (81% increase in AP RMS COP with 8 D blur). Performing an additional mental and physical task increased AP RMS COP by approximately 24%. All these detrimental effects on postural stability were cumulative.

Conclusions:  All the factors tested, except the additional physical task, significantly decreased postural stability and were cumulative. This highlights the multifactorial nature of balance control. Findings indicate that the visual system becomes increasingly relied upon when inputs from the other two balance control systems are disrupted.
Mindsight: pathological completion in a case of occipital damage without neglect
Authors: McCarthy R. A. , Galton M. , Plant G T.
Published: March 2003

Purpose:  Islands of blindness (scotomata) caused by damage to the visual regions of the brain may be accompanied by the subjective experience of completion of forms that ‘should’ be occluded by the visual defect, a symptom termed Pathological Visual Completion. We report our investigations of the basis of this phenomenon and the level of visual processing that is implicated.

Methods:  We report a single case with left occipital brain injury who showed pathological visual completion in a clear and reliable form. His disorder could not be explained by residual vision or an attentional disorder.

Results:  The likelihood of completion was systematically influenced by changes in the stimulus display. Pattern masking, varying the contrast characteristics of stimuli and changing visible cues to structural symmetry all had precise effects whereas familiarity and structural coherence did not.

Conclusion:  We suggest that in this case, pathological completion may be a positive cognitive event implicating processes that underpin the normal experience of occluded forms.