Age, lens transmittance, and the possible effects of light on melatonin suppression

Recently it has been suggested that a previously undetected, rhodopsin-based, visual pigment, located in some retinal ganglion cells and having a peak sensitivity around 460 nm, may be responsible for light-induced melatonin suppression and, perhaps, maintenance of the circadian rhythm. Using data from the literature, it is shown that, as absorption in the crystalline lens for shorter visible wavelengths increases substantially with age, while the pupil diameter tends to decrease, the effective retinal exposure received under the same ambient lighting conditions by the pigment is almost 10 times lower in an old, as compared with a young, eye. Interestingly, replacement of the old crystalline lens by an intraocular implant restores the exposure to youthful levels. The possible effects of these changes with age on circadian rhythms are discussed.     

Sub‐retinal neovascular membrane in exudative macular degeneration

Age‐related macular degeneration is a major cause of serious vision loss. The earliest stages of age‐related maculopathy may be defined by the size of the drusen present in the macula and the effects on vision. Further manifestations may include soft drusen, choroidal neovascularisation, macular haemorrhage and cicatricial or disciform degeneration of the macula. This report describes a patient with a macular haemorrhage, a choroidal neovascular membrane and serious loss of vision. In addition, the pathogenesis, diagnosis and treat‐ment options of macular degeneration are reviewed.     

Thrombophilic risk factors and unusual clinical features in three Italian CADASIL patients

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically transmitted cerebrovascular disease. Typically, the first clinical manifestation is migraine and the full clinical spectrum of the disease with recurrent strokes of the subcortical type, cognitive, and mood disorders is seen during the fourth and fifth decades of life. Vascular risk factors are usually absent in CADASIL patients and the diagnosis of the disease is particularly suspected in young adults with cerebrovascular events of unknown cause, diffuse leukoencephalopathy on computed tomography or magnetic resonance imaging, and a history of cerebrovascular diseases or dementia in many family members. We describe three Italian CADASIL patients who presented to medical attention for cerebrovascular events occurred after the age of 55 and had, in addition to hypertension and hyperlipidemia, thrombophilic risk factors such as hyperhomocysteinemia, elevated levels of lipoprotein(a), and antiphospholipid antibodies. Symptoms possibly related to cortical involvement, such as dysphasia and visual field deficits, were reported by two of these patients. We conclude that a diagnosis of CADASIL should not be disregarded in patients with vascular risk factors and presenting with symptoms not immediately referable to subcortical damage at ages more advanced than commonly reported.     

Macular electroretinogram as a function of age of subjects

Macular and paramacular electroretinograms in response to two adjacent checks (6 deg/side), alternating at constant mean luminance, were recorded in 34 normal subjects ranging in age from 16 to 74 years. The macular electroretinogram declines progressively in amplitude with age (R = –0.42; P = 0.013). The amplitude ratio between macular and paramacular responses tends to be independent of age (R = -0.21; P = 0.22).Age-related changes in the macular electroretinogram shown in our study are consistent with previous anatomical and functional studies, which indicate a deterioration of photoreceptors beyond 20 years of age. These results suggest a possible use of this technique for future studies on macular degeneration.     

Does ageing have an effect on midbrain premotor nuclei for vertical eye movements?

Currently, there is debate in the clinical literature as to whether defects in vertical gaze are a consequence of normal ageing or a component of an underlying neurodegenerative disorder. Although pathological changes have been demonstrated in diseased subjects, no study to date has addressed the question of normal ageing effects. In this retrospective study, we examined 23 neurologically and pathologically normal subjects (age 18-91). Using an unbiased, frame-based sampling method, we quantified neuronal and glial cell densities in 10 young (<50) and 13 aged (>65) subjects in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), the key premotor substrate in the vertical gaze pathway. We found no statistically significant difference in neuronal density, glial cell density, or neuron-to-glial cell ratios between the young and the aged. We conclude, therefore, that neuronal loss, neuronal atrophy, or gliosis in the riMLF are not consequences of normal ageing.     

Changes in elderly suicides in the USA and the developed world 1974–87: Comparison with current homicide

Between 1974 and 1987 there were increases overall in male suicide rates in the USA, with the greatest increases among elderly men. While female suicide levels overall fell in the USA, elderly female suicide rates failed to show the same improvement. Compared with the rest of the western world, suicide rates for elderly people in the USA were among the worst. Suicide was far more prevalent than homicide, but this is not reflected in the media, where homicide is given a high profile but where there is relative silence surrounding suicide among elderly people.     

The Dubbelman eye model analysed by ray tracing through aspheric surfaces

Dubbelman and co-workers have determined intraocular spacings and surface shapes in living eyes by means of corrected Scheimpflug images in a large number of subjects of different age at several levels of accommodation. They give relationships for key anterior segment parameters as a function of age and level of accommodation. These are used in this paper to build a schematic eye incorporating aspheric surfaces. This eye model is analysed by means of ray tracing with a technique developed for use with a common spreadsheet computer program. The Dubbelman eye model appears to be well corrected for spherical aberration. Compared with measurements on real eyes it agrees well in general, but spherical aberration is negative, while in real eyes it tends to be positive.     

早产儿与足月新生儿血清脂联素水平比较

目的探讨早产对血清脂联素水平的影响及早产成为成人期2型糖尿病、心血管疾病发生的重要危险因素可能机制。方法 采用放射免疫分析法,测定30例正常足月新生儿和21例早产儿血清脂联素水平结果早产儿血清脂联素水平(34.29±7.24)mg/L,正常足月新生儿血清脂联素水平(62。47±28.33)mg/L,早产儿血清脂联素水平显著低于足月新生儿(P<0.001);血清脂联素水平与胎龄(r-0.386 P<0.005)、出生体质量(r=0.432 P<0.005)均呈显著正相关 结论 早产儿具有较低血清脂联素水平;胎儿宫内发育不良引起早产或低出生体质量,进而降低其血清脂联素水平,可能是该群体日后发生2型糖尿病、动脉粥样硬化、代谢综合征的重要危险因素     

Age-Dependent Prevalence of Cardioembolic Sources Detected by TEE: Diagnostic and Therapeutic Implications

To define the prevalence of cardioembolic sources found by transesophageal echocardiography (TEE) in different age groups of patients with and without cryptogenic systemic embolism, TEE risk factors for cardiogenic embolism were identified from 341 consecutive patients referred for TEE. One hundred and thirty-five had cryptogenic cerebral or systemic peripheral embolic events (CEE) and 206 other indications for TEE (CTR). Cardioembolic sources were found in 40% of CEE and in 29% of CTR (P < 0.02). Specifically, left atrial (LA) thrombi (P < 0.0001), atrial septal aneurysm with right-to-left shunt (P < 0.002), and atherosclerotic aortic plaques (P < 0.02) were more frequent. The prevalence of potential cardioembolic sources was significantly higher in patients ≥ 70-years old than in younger patients (P < 0.03), specifically LA thrombi (P < 0.004) and atherosclerotic aortic plaques (P < 0.0001). In patients ≥ 70-years old, potential cardioembolic sources were found in 63% and in 40% in CEE and CTR (P = 0.073), respectively. However, LA thrombi were more frequent in CEE (P < 0.003). Thus, potential cardioembolic sources observed by TEE are found more frequently in patients ≥ 70-years old than in younger patients. LA thrombi were more frequent in CEE than in CTR patients ≥ 70-years old. In patients ≥ 70-years old with CEE who are eligible for an anticoagulant regimen, a search for potential cardioembolic sources by TEE should be considered.