Optic disk anomalies [abstract]

There are a number of development defects of the nerve that result in disk anomalies that present as diagnostic and management problems. These include pseudo-papilloedema, disk hypoplasia; crescent anomalies; and partial colobomas. These will be discussed in clinical context, especially "misdiagnosis". (AU)

Cortical visual loss in a young woman with systemic lupus erythematosus

A 29-year old West Indian woman presented with a one year history of gradual visual loss. There was a past history of psychiatric illness. Examination revealed normal optic nerve function bilaterally. The retinae appeared healthy. Visual acuities were down. A computed tomography brain scan showed mark cerebral atrophy particularly in the occipital areas. The ESR was elevated at 111 mm, Westergen, 1st hour. The ANF was strongly positive. A diagnosis of cerebral lupus was made. The patient has been started on immunosuppressive therapy. (AU)

"Back from the brink": benign intracranial hypertension [abstract]

Benign intracranial hypertension (BIH) is a misnomer. The prefix underscores the fact that the condition can cause irreversible blindness. BIH is an enigmatic condition, which can be associated with ingestion of various substances such as excess vitamin A, nalidixic acid, steroids and tetracyclines. It can also be produced by diverse conditions such as dural sinus thrombosis and sleep apnoea. A case is presented which emphasizes the gravity of the condition and the damage that can ensue to the optic nerves. The management needs to be aggressive if this damage is to be minimized and halted. BIH appears to be more common that previously thought and clues are emerging as to its aetiology particularly in relation to sleep apnoea. This demonstrates that the optic nerves, structurally or metabolically, can be subject to influences from a number of systemic conditions. By extrapolation, it begs the question as to whether another opthalmic conundrum - the optic neuropathy of chronic open angle glaucoma - may have some parallels with the pathogenesis of BIH. In particular, it suggests that a broader prospective should be taken in seeking the pathogenesis of chronic open angle glaucoma. (AU)

All that glitters is not glaucoma

The twentieth century has witnessed great strides in the understanding and management of the major ophthalmic conditions. For example, the surgical treatment of cataract is being honed to perfection with only the goal of accommodative restoration remaining to complement visual clarity. Understanding of the mode of transmission of Chlamydia trachomaitis, plus the new macrolide antimicrobial, azithromycin, which can cure 80 percent of acute trachoma, offers hope in managing this infection. Similarly, the control of the vector Simulium and the microfilariacidal, Ivermectin, promise to eradicate onchocerciasis volvolus. Increasing understanding of the pathogenesis of the microangiopathy of diabetic retinopathy and the recent trials - Diabetic Control and Complication Trial and the European Prospective Study - have paved the way for the control of this condition. However, our understanding and management of chronic open angle glaucoma remains frustratingly elusive. Problems related to the early detection and monitoring progression remain imprecise and sometimes non-specific and misleading. Two cases are presented to illustrate the limitations of the visual field test and underline the fact that it should never be viewed in isolation. Further treatment modalities will dictate more precise objective tests for monitoring optic nerve function, focusing on early diagnosis and small degrees of progression.(AU)

The approach of neuroprotection for the new millennium

A review of the mechanism of retinal ganglion cell and optic nerve damage in glaucoma will be discussed as well as autoregulation of blood flow in the optic nerve. Treatment utilizing the approach of neuroprotection and the evolution of calcium channel blocking activity will be shown. (AU)

Neuroprotection in glaucoma

Neuroprotection has emerged as an important conception the treatment of ocular neurodegenerative diseases, including glaucoma. In order to identify drugs with neuroprotective potential, animal models of retina and optic nerve degeneration have been developed. The optic nerve mechanical injury and pressure induced retinal ischaemia rodent models evaluate activity at the inner retina/optic nerve; and at the outer retina the light induced photoreceptor degeneration rodent model was utilized. Functional and morphometric assessment of the retina was made up to two weeks following the mechanical insults to quantitate secondary neuronal degeneration after injury. This type of neuronal cell death shares some characteristics with chronic neurodegenerative diseases. Brimonidine, an alpha-2 adrenoceptor agonist, was neuroprotective in these animal models. Moreover, the data show that the effect is mediated through alpha-2 adrenoceptors and involves, in part, the upregulation of antiapoptotic and neuronal survival genes.(AU)

Optic nerve and retinal contributions to visual loss in epidemic optic neuropathy

The largest neurological epidemic this century has recently occurred in Cuba where 50,000 cases of epidemic optic and peripheral neuropathy have been reported. The disorder closely resembles Strachan's syndrome described in the Caribbean in the late 19th century and a similar epidemic disorder which I have studied in Tanzania. Electrophysiological studies have indicated both optic nerve and retinal involvement in cases from Tanzania. (Plant et al..., J Neurol Sci 145 1997 127-140). Subsequently 25 Cuban patients have been studied, all in the chronic phase of the disease all with a stable residual deficit. Electroretinography revealed normal rod function but an unusual abnormality of post-receptoral core function. Specifically the response to turning the light stimulus off was abnormal showing a lower amplitude than in control subjects. These results will be discussed in the context of other toxic and nutritional disorders affecting the retina and optic nerve in the tropics and elsewhere.(AU)

Cupping of the optic disc in the Jamaican population

The cup/disc of the optic nerves of 289 normal eyes of 145 persons were studied. The frequency of wide physiological cups in a Jamaican group was compared with eight other groups. The Jamaican group had an incidence of wide physiological cups that exceeded that of the others by two or three times. This high incidence of wide cups in the normal Jamaican population has profound implications for the management of glaucoma in Jamaica. The high incidence of wide, non-glaucomatous, cupping can be explained on the basis of racial factors (AU)

Demyelinating disease in a woman from tropical South America with features of multiple sclerosis and neuromyelitis opticaz: clinical, protein chemistry and pathological findings

The ocurrence of demyelinating disease with many of multiple sclerosis and of neuromyelitis optica in a patient born and brought up in Guyana in tropical South America is so exceptional as to merit an individual case report. The similarities and differences between the findings in this patient and those accepted as typical of these diseases, as they are commonly known, are discussed in detail. (AU)