Sublime Wong Kar-wai

In the films of Wong Kar-wai one finds a double or parallel sensing of the sublime. Numerous characters are seen to experience perceptual moments of unbounded terror, where they are faced with the weight, enormity or formlessness of objects, things, and natural phenomena that they cannot initially or fully comprehend. These ‘textual’ sublime moments are simultaneously rendered receptively, experientially sublime through the way Wong Kar-wai conjures up a series of refracted, defamiliarised images of heightened intensity, such as bejeweled juke boxes, incandescent lampshades, thick waterfalls, and wispy cigarette smoke rising. Such awesome images are of artifice and nature, conjoined, blurred, or delineated, so that the sublime moment is of the postmodern moment, irrational and irregular, and ‘monstrous’ because of it. In the films of Wong Kar-wai, character and viewer become aligned in a process of identification in which each recognizes their mortality, and inadequacy, in the face of such dazzling, incomprehensible moments that trace across the retina of the eye. The pleasure and the pain of this is something that I will explore in this paper, using such sublime films as Fallen Angels, Chungking Express, Happy Together, In the Mood for Love, 2046, and Blueberry Nights, to illustrate my arguments.

Resolution considerations in spatially variant sensors

Log polar transformations for space variant systems have been proposed and used in active vision research. The idea is to generate an image with a varying resolution over a wide angle field of view. The fovea is of high resolution and the periphery is of exponentially reduced resolution. The justifications for such a sensor are: (i) it provides high resolution and a wide viewing angle, (ii) feature invariance in the fovea simplifies foveation, and (iii) it allows multiresolution analysis. The receptor density of the human retina is very high, i.e. of the order of 106 receptors at the fovea. The question is, what resolution should space variant active vision systems have? Real visual sensors have been implemented but is the resolution produced high enough? This paper investigates the resolution requirements of a space variant sensor by simulation for a tracking system using raytracing

Absorbance of retinal oil droplets of the budgerigar : sex, spatial and plumage morph-related variation

Intraspecific variation in photoreceptor physiology is known in several vertebrate taxa, but is currently unknown in birds, despite many avian traits varying intraspecifically, and avian visual ecology encompassing a wide range of environments and visual stimuli, which might influence spectral sensitivity. Avian retinal photoreceptors contain light absorbing carotenoid-rich oil droplets that affect vision. Carotenoids are also important plumage components. However, our understanding of the regulation of carotenoids in oil droplets remains rudimentary. Among birds, Melopsittacus undulatus has probably the best-studied colour vision, shows profound intraspecific variation in plumage colour, and increased plasma carotenoids during moult. We used microspectrophotometry to determine whether a relationship exists between oil droplet carotenoid concentration and plumage pigmentation, and tested for sex and spatial variation in droplet absorbance across the retina. Absorbance of one variety of P-type droplets was higher in males. No relationship was found between droplet absorbance and plumage colour. We found a spatial pattern of droplets absorbance across the retina that matched a pattern found in another parrot, and other avian species. Our work provides insights into the development and maintenance of retinal oil droplets and suggests a common mechanism and function for carotenoid deposition in the retina across bird species.

Shared care for chronic eye diseases : perspectives of ophthalmologists, optometrists and patients

Objective: To report the perspectives of optometrists, ophthalmologists and patients on a model of shared care for patients with chronic eye diseases.

Design, setting and participants: Qualitative study of a model of shared care between optometrists and ophthalmologists for patients with stable age-related macular degeneration, diabetic retinopathy and glaucoma, trialled by the Royal Victorian Eye and Ear Hospital in Melbourne during 2007–2009. Semi-structured interviews were conducted with optometrists, ophthalmologists and patients at completion of the project to obtain their perspectives on this model.

Results: Seventeen optometrists submitted expressions of interest to participate, and 12 completed web-based training modules and clinical observerships and adhered to specified examination and reporting protocols. All five participating ophthalmologists and 11 of the optometrists were interviewed. Ninety-eight patients participated and 37 were interviewed. Optometrists not only met ophthalmologists’ expectations but exceeded them, appropriately detecting and referring patients with additional, previously undetected conditions. Patients reported savings in travel time and were satisfied with the quality of care they received. Optometrists, ophthalmologists and patients indicated a general acceptance of shared care arrangements, although there were some issues relating to interprofessional trust.

Conclusions: Shared care between local optometrists and hospital-based ophthalmologists can help to reduce patient waiting time for review and offers an opportunity for these two groups of eye care professionals to collaborate in providing localised care for the benefit of patients. However, trust and relationship building need to be further developed.

Blood pressure modifies retinal susceptibility to intraocular pressure elevation

Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP) is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP). An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine) Long-Evan rats with low (~60 mmHg, sodium nitroprusside infusion), moderate (~100 mmHg, saline), or high levels (~160 mmHg, angiotensin II) of mean arterial pressure (MAP, n = 5–10 per group) were subjected to IOP challenge (10–120 mmHg, 5 mmHg steps every 3 minutes). Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave) and inner retinal function (scotopic threshold response or STR). Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow.

Electroretinography in streptozotocin diabetic rats following acute intraocular pressure elevation

Background
We consider whether pre-existing streptozotocin induced hyperglycemia in rats affects the ability of the eye to cope with a single episode of acute intraocular pressure (IOP) elevation.
Methods
Electroretinogram (ERG) responses were measured (−6.08 to 1.92 log cd.s.m−2) in anaesthetized (60:5 mg/kg ketamine:xylazine) dark-adapted (>12 h) adult Sprague–Dawley rats 1 week after a single acute IOP elevation to 70 mmHg for 60 min. This was undertaken in rats treated 11 weeks earlier with streptozotocin (STZ, n = 12, 50 mg/kg at 6 weeks of age) or citrate buffer (n = 12). ERG responses were analyzed to derive an index of photoreceptor (a-wave), ON-bipolar (b-wave), amacrine (oscillatory potentials) and inner retinal (positive scotopic threshold response, pSTR) function.
Results
One week following acute IOP elevation there was a significant reduction of the ganglion cell pSTR (−35 ± 11 %, P = 0.0161) in STZ-injected animals. In contrast the pSTR in citrate-injected animals was not significant changed (+16 ± 14 %). The negative component of the STR was unaffected by IOP elevation in either citrate or STZ-treated groups. Photoreceptoral (a-wave, citrate-control +4 ± 3 %, STZ +4 ± 5 %) and ON-bipolar cell (b-wave, control +4 ± 3 %, STZ +4 ± 5 %) mediated responses were not significantly affected by IOP elevation in either citrate- or STZ-injected rats. Finally, oscillatory potentials (citrate-control +8 ± 23 %, STZ +1 ± 17 %) were not reduced 1 week after IOP challenge.
Conclusions
The ganglion cell dominated pSTR was reduced following a single episode of IOP elevation in STZ diabetic, but not control rats. These data indicate that hyperglycemia renders the inner retina more susceptible to IOP elevation.

Feedback of personal retinal images appears to have a motivational impact in people with non-proliferative diabetic retinopathy and suboptimal HbA1c: findings of a pilot study

AIM:
To conduct a pilot study to explore the potential impact of visual feedback of personal retinal images on diabetes outcomes.

METHODS:
Twenty-five participants with non-proliferative diabetic retinopathy and suboptimal HbA1c (> 53 mmol/mol; > 7%) were randomized to receive visual feedback of their own retinal images or to a control group. At baseline and 3-month follow-up, HbA1c, standard measures of beliefs, diabetes-related distress and self-care activities were assessed.

RESULTS:
In unadjusted models, relative to controls, the intervention group showed significantly greater improvement in HbA1c at 3-month follow-up (–0.6% vs. +0.3%, P < 0.01), as well as enhanced motivation to improve blood glucose management (P < 0.05).

CONCLUSIONS:
This small pilot study provides preliminary evidence that visual feedback of personal retinal images may offer a practical educational strategy for clinicians in eye care services to improve diabetes outcomes in non-target compliant patients. A fully powered randomized controlled trial is required to confirm these findings and determine the optimal use of feedback to produce sustained effects.

Expression of muscarinic receptor subtypes in tree shrew ocular tissues and their regulation during the development of myopia

Muscarinic receptors are known to regulate several important physiologic processes in the eye. Antagonists to these receptors such as atropine and pirenzepine are effective at stopping the excessive ocular growth that results in myopia. However, their site of action is unknown. This study details ocular muscarinic subtype expression within a well documented model of eye growth and investigates their expression during early stages of myopia induction. Total RNA was isolated from tree shrew corneal, iris/ciliary body, retinal, choroidal, and scleral tissue samples and was reverse transcribed. Using tree shrew-specific primers to the five muscarinic acetylcholine receptor subtypes (CHRM1-CHRM5), products were amplified using polymerase chain reaction (PCR) and their identity confirmed using automated sequencing. The expression of the receptor proteins (M1-M5) were also explored in the retina, choroid, and sclera using immunohistochemistry. Myopia was induced in the tree shrew for one or five days using monocular deprivation of pattern vision, and the expression of the receptor subtypes was assessed in the retina, choroid, and sclera using real-time PCR. All five muscarinic receptor subtypes were expressed in the iris/ciliary body, retina, choroid, and sclera while gene products corresponding to CHRM1, CHRM3, CHRM4, and CHRM5 were present in the corneal samples. The gene expression data were confirmed by immunohistochemistry with the M1-M5 proteins detected in the retina, choroid, and sclera. After one or five days of myopia development, muscarinic receptor gene expression remained unaltered in the retinal, choroidal, and scleral tissue samples. This study provides a comprehensive profile of muscarinic receptor gene and protein expression in tree shrew ocular tissues with all receptor subtypes found in tissues implicated in the control of eye growth. Despite the efficacy of muscarinic antagonists at inhibiting myopia development, the genes of the muscarinic receptor subtypes are neither regulated early in myopia (before measurable axial elongation) nor after significant structural change.

Exploring retinal and functional markers of diabetic neuropathy

Diabetic peripheral neuropathy (DPN) is one of the most debilitating complications of diabetes. DPN is a major cause of foot ulceration and lower limb amputation. Early diagnosis and management are key factors in reducing morbidity and mortality. Current techniques for clinical assessment of DPN are relatively insensitive for detecting early disease or involve invasive procedures such as skin biopsies. There is a need for less painful, non-invasive, safe evaluation methods. Eye-care professionals already play an important role in the management of diabetic retinopathy but recent studies have indicated that the eye may also be an important site for the diagnosis and monitoring of neuropathy. Corneal nerve morphology is a promising marker of diabetic neuropathy occurring elsewhere in the body. Emerging evidence tentatively suggests that retinal anatomical markers and a range of functional visual indicators could similarly provide useful information regarding neural damage in diabetes, although this line of research is less well established. This review outlines the growing body of evidence supporting a potential diagnostic role for retinal structure and visual functional markers in the diagnosis and monitoring of peripheral neuropathy in diabetes.

Photoreceptor topography and spectral sensitivity in the common brushtail possum (Trichosurus vulpecula)

Marsupials are believed to be the only non-primate mammals with both trichromatic and dichromatic color vision. The diversity of color vision systems present in marsupials remains mostly unexplored. Marsupials occupy a diverse range of habitats, which may have led to considerable variation in the presence, density, distribution, and spectral sensitivity of retinal photoreceptors. In this study we analyzed the distribution of photoreceptors in the common brushtail possum (Trichosurus vulpecula). Immunohistochemistry in wholemounts revealed three cone subpopulations recognized within two spectrally distinct cone classes. Long-wavelength sensitive (LWS) single cones were the largest cone subgroup (67-86%), and formed a weak horizontal visual streak (peak density 2,106 ± 435/mm2) across the central retina. LWS double cones were strongly concentrated ventrally (569 ± 66/mm2), and created a "negative" visual streak (134 ± 45/mm2) in the central retina. The strong regionalization between LWS cone topographies suggests differing visual functions. Short-wavelength sensitive (SWS) cones were present in much lower densities (3-10%), mostly located ventrally (179 ± 101/mm2). A minority population of cones (0-2.4%) remained unlabeled by both SWS- and LWS-specific antibodies, and may represent another cone population. Microspectrophotometry of LWS cone and rod visual pigments shows peak spectral sensitivities at 544 nm and 500 nm, respectively. Cone to ganglion cell convergences remain low and constant across the retina, thereby maintaining good visual acuity, but poor contrast sensitivity during photopic vision. Given that brushtail possums are so strongly nocturnal, we hypothesize that their acuity is set by the scotopic visual system, and have minimized the number of cones necessary to serve the ganglion cells for photopic vision.

Upregulation of sodium iodide symporter (NIS) protein expression by an innate immunity component: promising potential for targeting radiosensitive retinoblastoma

Retinoblastoma (RB), a malignant tumour of the eye arising from developing retina, is the most frequent primary intraocular malignancy of childhood. Its primary management with chemotherapy involves combination regimen of etoposide, vincristine and carboplatin and intra vitreal chemotherapy using melphalan when vitreous seeds develop. Radiotherapy is another effective mode in treating RB. We recently explored the notion if radiotherapy in RB can be mediated via Sodium Iodide Symporter (NIS), an intrinsic membrane glycoprotein which is a key regulator of iodide access to thyroid gland. Its expression has been exploited successfully for diagnostic imaging and molecular radionuclide-based therapy of thyroid cancer. We determined that NIS is expressed endogenously in RB tumour tissues, and in retinoblastoma cell lines Y79 and Weri-Rb-1, and therefore made an attempt to enhance the endogenously low expression of NIS protein in both Y79 and Weri-Rb-1 cells. Here we report about the potential of bovine lactoferrin (bLf) which is a known chemo preventive and emerging safe anti-cancer bio drug, as well as a natural transcriptional activator of genes, to enhance the endogenous expression of NIS in Y79 and Weri-Rb-1 cells. Real time PCR revealed that both cell lines express mRNA of lactoferrin receptors while flow cytometry and confocal microscopy showed the cells efficiently internalize bLf which upregulates NIS expression. These findings highlight an important step that could be taken towards the development of less harmful approaches for the treatment of RB by employing natural supplement bLf (with its clinically proven safe profile), and warrants further studies in future, focussing on enhancing NIS expression in RB cells and NIS functional assays in these cells.

Visually guided eye growth in the squid

Summary Eyes with refractive error have reduced visual acuity and are rarely found in the wild. Vertebrate eyes possess a visually guided emmetropisation process within the retina which detects the sign of defocus, and regulates eye growth to align the retina at the focal plane of the eye's optical components to avoid the development of refractive error, such as myopia, an increasing problem in humans [1]. However, the vertebrate retina is complex, and it is not known which of the many classes of retinal neurons are involved [2]. We investigated whether the camera-type eye of an invertebrate, the squid, displays visually guided emmetropisation, despite squid eyes having a simple photoreceptor-only retina [3]. We exploited inherent longitudinal chromatic aberration (LCA) to create disparate focal lengths within squid eyes. We found that squid raised under orange light had proportionately longer eyes and more myopic refractions than those raised under blue light, and when switched between wavelengths, eye size and refractive status changed appropriately within a few days. This demonstrates that squid eye growth is visually guided, and suggests that the complex retina seen in vertebrates may not be required for emmetropisation.