Regulation of oxygen saturation in retinal blood vessels in response to dynamic exercise

Purpose: To evaluate the impact of dynamic exercise on retinal vessel oxygen saturation in healthy individuals. Methods: Twenty-six healthy participants underwent moderate dynamic exercise (modified Master’s two step exercise). All subjects intraocular pressures (IOP), systolic and diastolic blood pressure (SBP and DBP), retinal vessel calibres and retinal arterial and venous oxygen saturation was measured at baseline, immediately following exercise and 15 minutes post exercise. Results: Moderate dynamic exercise increased systolic and diastolic blood pressures immediately post exercise (SBP: 116 (+/-13) mmHg to 150 (+/-21) mmHg; p<0.001 and DBP: 69 (+/-10) mmHg to 74 (+/-10); p<0.001) while IOP decreased by an average of 2 mmHg (baseline: 13 (+/-3) mmHg)) immediately post exercise (11 (+/-2) mmHg). Oxygen saturation in retinal arteries remained unchanged (baseline= 93 +/-8%; immediately post exercise=94 +/-9% and 15 minutes post exercise=96 +/-8%; p=0.069) but increased in retinal veins immediately post exercise and did not return to baseline values within 15 minutes post exercise (baseline=54 +/-12%; immediately post exercise=56 +/-15%; 15 minutes post exercise=57 +/-12%; p=0.036).  Conclusion: There is a mild increase in retinal venous oxygen saturation and a trend towards an increase in arterial saturation in otherwise healthy individuals following dynamic exercise

Submarine groundwater discharge and associated chemical input to a coastal sea

This paper presents a theoretical model of flow and chemical transport processes in subterranean estuaries (unconfined brackish groundwater aquifers at the ocean-land interface). The model shows that groundwater circulation and oscillating flow, caused by wave setup and tide, may constitute up to 96% of submarine groundwater discharge (SGWD) compared with 4% due to the net groundwater discharge. While these local flow processes do not change the total amount of land-derived chemical input to the ocean over a long period (e.g., yearly), they induce fluctuations of the chemical transfer rate as the aquifer undergoes saltwater intrusion. This may result in a substantial increase in chemical fluxes to the ocean over a short period (e.g., monthly and by a factor of 20 above the averaged level), imposing a possible threat to the marine environment. These results are essentially consistent with the experimental findings of Moore [1996] and have important implications for coastal resources management

Ocular disease in patients with ANCA-positive vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-positive vasculitis—the term recently applied to Wegener's granulomatosis—is a rare multi-system inflammation characterized by necrotizing granulomas and vasculitis. We investigated the ocular manifestations of this disease in a group of patients drawn from five inflammatory eye disease clinics across the United States. Of 8,562 persons with ocular inflammation, 59 individuals were diagnosed with ANCA-positive vasculitis; 35 males and 21 females, aged 16 to 96 years, were included in this study. Ocular diagnoses were scleritis (75.0%), uveitis (17.9%), and other ocular inflammatory conditions (33.9%) including peripheral ulcerative keratitis and orbital pseudotumor. Mean duration of ocular disease was 4.6 years. Oral corticosteroids and other systemic immunosuppressive agents were used by 85.7% and 78.5% of patients, respectively. Over time, patients with ANCA-positive vasculitis experienced 2.75-fold higher mortality than other patients with inflammatory eye disease

The Prevalence of Visual Impairment in People with Dementia (the PrOVIDe study): a cross-sectional study of people aged 60–89 years with dementia and qualitative exploration of individual, carer and professional perspectives

Background: The prevalence of visual impairment (VI) and dementia increases with age and these conditions may coexist, but few UK data exist on VI among people with dementia. Objectives: To measure the prevalence of eye conditions causing VI in people with dementia and to identify/describe reasons for underdetection or inappropriate management. Design: Stage 1 – cross-sectional prevalence study. Stage 2 – qualitative research exploring participant, carer and professional perspectives of eye care. Setting: Stage 1 – 20 NHS sites in six English regions. Stage 2 – six English regions. Participants: Stage 1 – 708 participants with dementia (aged 60–89 years): 389 lived in the community (group 1) and 319 lived in care homes (group 2). Stage 2 – 119 participants. Interventions: Stage 1 gathered eye examination data following domiciliary sight tests complying with General Ophthalmic Services requirements and professional guidelines. Cognitive impairment was assessed using the Standardised Mini-Mental State Examination (sMMSE) test, and functional ability and behavior were assessed using the Bristol Activities of Daily Living Scale and Cambridge Behavioural Inventory – Revised. Stage 2 involved individual interviews (36 people with dementia and 11 care workers); and separate focus groups (34 optometrists; 38 family and professional carers). Main outcome measures.: VI defined by visual acuity (VA) worse than 6/12 or worse than 6/18 measured before and after refraction. Results: Stage 1 – when participants wore their current spectacles, VI prevalence was 32.5% [95% confidence interval (CI) 28.7% to 36.5%] and 16.3% (95% CI 13.5% to 19.6%) for commonly used criteria for VI of VA worse than 6/12 and 6/18, respectively. Of those with VI, 44% (VA 80% of participants. There was no evidence that the management of VI in people with dementia differed from that in older people in general. Exploratory analysis suggested significant deficits in some vision-related aspects of function and behaviour in participants with VI. Stage 2 key messages – carers and care workers underestimated how much can be achieved in an eye examination. People with dementia and carers were unaware of domiciliary sight test availability. Improved communication is needed between optometrists and carers; optometrists should be informed of the person’s dementia. Tailoring eye examinations to individual needs includes allowing extra time. Optometrists wanted training and guidance about dementia. Correcting VI may improve the quality of life of people with dementia but should be weighed against the risks and burdens of undergoing examinations and cataract surgery on an individual basis. Limitations: Sampling bias is possible owing to quota-sampling and response bias. Conclusions: The prevalence of VI is disproportionately higher in people with dementia living in care homes. Almost 50% of presenting VI is correctable with spectacles, and more with cataract surgery. Areas for future research are the development of an eye-care pathway for people with dementia; assessment of the benefits of early cataract surgery; and research into the feasibility of specialist optometrists for older people

Wegener's granulomatosis: Ophthalmic manifestations and management

ObjectivesTo provide an up-to-date and comprehensive review of Wegener's granulomatosis (WG) as a disease entity, focusing on the ophthalmic manifestations and management options.MethodsA search of Medline was undertaken between 1966 and 2005 regarding WG, systemic vasculitis, and the ocular manifestations of WG. Major ophthalmic and medical textbooks also were reviewed for content, as well as original references.ResultsInvolvement of ocular and orbital structures in patients with WG is common and may be a presenting feature. The ocular manifestations range from mild conjunctivitis and episcleritis to more severe inflammation with keratitis, scleritis, uveitis, and retinal vasculitis. Involvement of the nasolacrimal system and orbital tissues also can occur. Except for some cases of anterior segment inflammation, the ocular involvement will not respond to topical agents, but rather to systemic antiinflammatory and immunosuppressive regimens. Surgical intervention may be of value for obtaining tissue diagnosis, in achieving orbital decompression in cases of significant orbital disease with optic nerve compromise, or in cases of nasolacrimal duct obstruction.ConclusionWG is an important clinical entity that needs to be recognized early and treated appropriately. Ophthalmic manifestations are frequently encountered and can result in significant morbidity and even blindness. The management is challenging and often requires a multidisciplinary approach.Nima Pakrou, Dinesh Selva and Igal Leibovitc

Neuro-ophthalmic manifestations of intracranial cavernous hemangiomas

PurposeTo describe the neuro-ophthalmic manifestations of patients with intracranial cavernous hemangiomas (cavernomas).MethodsA retrospective review of all patients with intracranial cavernomas with neuroophthalmic manifestations who were treated at the Royal Adelaide Hospital in Australia between 1994 and 2004.ResultsThere were nine patients (three men and six women), with a mean age of 39 years (range 22-61). There was one cerebellar lesion, two thalamic, four pontine, one midbrain/pontine, and one midbrain. Ophthalmic presentations included internuclear ophthalmoplegia (one patient), third cranial nerve (CN) palsy (one patient), fourth CN palsy (one patient), and sixth CN palsy (six patients). Three patients underwent extraocular muscle surgery, and six were treated medically or observed. In five patients the diplopia resolved, in three it was only mild, and in one patient no significant change was noted during the follow-up period.ConclusionsDiplopia is the main neuro-ophthalmic manifestation of intracranial cavernomas. Sixth CN palsy is the most common cause. Neurosurgical or conservative treatment leads to improvement in most cases, and later use of spectacles or extraocular muscle surgery may lead to further improvement