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Biomedical subjects

E L Chuang

Publications and source records attributed to E L Chuang.

12 recordsLinked to original sources
PubMed1992

Management of retinal detachment associated with CMV retinitis in AIDS patients.

In patients with AIDS, the most important ocular opportunistic infection, CMV retinitis, can now be treated effectively with virostatic agents. Associated retinal detachment is encountered frequently, and its management has become increasingly significant to quality of life as improvements in medical care have helped to preserve vision and extend life expectancy. Although retinal detachment in these eyes is typically rhegmatogenous, the pathophysiology is distinctive due to the association with CMV retinitis which, even in remission, is characterised by atrophic changes at all levels of affected retina and alterations of the vitreous. Despite initially successful surgical reattachment, multiple, small, often posterior holes may develop because of progressive CMV infection. For these reasons, vitrectomy and silicone oil injection with scleral buckling may currently provide the best overall means of maintaining retinal reattachment and restoring visual function. Nevertheless, management must be individualised in each case, with the realisation that progressive visual loss frequently ensues from retinitis progression.

AIDS-Related Opportunistic Infections↗
PubMed1991

Detection of herpesvirus DNA in vitreous and aqueous specimens by the polymerase chain reaction.

Members of the herpesvirus family, cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus (HSV), have been recognized as causal agents of chorioretinal inflammatory diseases. We investigated the use of the polymerase chain reaction for the detection of CMV, HSV, and EBV genomes in aqueous, subretinal fluid, and vitreous specimens in patients with clinically diagnosed CMV retinitis. Cytomegalovirus but not HSV or EBV genomic sequences were detected in all of these clinical specimens. We also investigated 18 normal aqueous and eight normal vitreous specimens obtained from patients undergoing cataract or vitrectomy surgery. Cytomegalovirus, HSV, and EBV DNA were not detected in any of the normal aqueous specimens. There was one weakly positive CMV normal vitreous, but none was HSV or EBV positive by the polymerase chain reaction. These results indicate that the polymerase chain reaction may be useful as a rapid and sensitive diagnostic technique to aid in the confirmation of clinical observations.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Treatment of iatrogenic choriovitreal neovascularisation in sickle cell disease.

The effect of scatter photocoagulation on the perfusion of iatrogenic choriovitreal neovascularisation (CVN) has been assessed by a randomised trial in 35 CVN lesions in 18 eyes with proliferative sickle retinopathy. No difference in size or vascularity of CVN lesions was apparent between the nine treated and nine control eyes over a median follow-up of 42 months. Scatter photocoagulation by the stated protocol was not effective in the treatment of CVN.

Adult↗
PubMed1989

The risk of fellow eye visual loss with unilateral retinal pigment epithelial tears.

To identify the magnitude of risk of fellow-eye visual loss, we reviewed the records of 43 patients with unilateral central visual loss caused by a tear of detached retinal pigment epithelium seen in our institution over a period of one to 13 years. Loss of vision because of complications of age-related macular disease occurred in 16 of 43 patients (37%) in the first year, seven of 23 patients (30%) in the second year, and eight of 16 patients (50%) in the third year. An additional five patients lost visual acuity between the third and eighth years of follow-up. The cumulative risk of loss of visual acuity was 37% in one year, 59% in two years, and 80% in three years. Visual loss occurred in 29 of the 36 eyes as a result of a complication of retinal pigment epithelial detachment. The magnitude of risk to the fellow eye was greater than has been documented in unselected age-related macular degeneration.

Aged↗
PubMed1988

The pathogenesis of tears of the retinal pigment epithelium.

We compared drusen in the fellow eye of patients with unilateral retinal pigment epithelial tears with those in an age- and sex-matched group of patients with unilateral primary neovascular disciform lesions. In the fellow eye of patients with tears, drusen were more confluent and manifested less fluorescence on angiography than in the comparison group. These observations are in accord with the concept that Bruch's membrane represents a significant barrier to fluid flow, and that fluid beneath detached pigment epithelium is derived in part or wholely from the pigment epithelium.

Aged↗
PubMed1988

Repair after tears of the retinal pigment epithelium.

Sixty-three eyes (in 59 patients) with tears of detached retinal pigment epithelium have been studied for a period of up to 10 years after the acute event. In the majority of cases a plaque of fibrous tissue was laid down gradually in the bed of the tear. In a few eyes the inner surface of Bruch's membrane appeared to remain relatively unaltered for up to 2 years, and in four eyes it was recovered with pigmented tissue resembling normal retinal pigment epithelium. These and other changes progressively obscured the distinctive feature of the original lesion; the nature of the original lesion was evident at 6 months in all cases, by 1 year it was recognisable in 94 per cent, by 2 years in 77 per cent and by 6 years in none. Choroidal neovascularisation was detected or suspected in one third of cases in the acute stages and developed in others weeks to months after the acute event. Alteration of the morphology occurred more quickly, and there was greater scarring, in those with new vessels or significant blood in the subretinal space, when compared with those without such features. Visual acuity was surprisingly good in many patients immediately after the tear. However, loss of vision accompanied the reactive tissue remodelling, and no case had long term retention of good visual acuity.

Aged↗
PubMed1988

Bilaterality of tears of the retinal pigment epithelium.

Eyes with tears of detached retinal pigment epithelium have been studied for up to 10 years following the acute event. In a retrospective study it has been determined that such a lesion in one eye implies a high risk of a similar event occurring in the fellow eye. Patients with loss of vision in their second eye as a result of a pigment epithelial tear were also studied; in 10 of 22 patients a similar lesion could be identified in the first eye. These observations suggest that these patients have specific changes at the level of Bruch's membrane which predispose to this particular manifestation of age related macular disease.

Age Factors↗
PubMed1987

Retinal dysfunction in central serous retinopathy.

Patients with acute and chronic central serous retinopathy (CSR) were studied by psychophysical and photochemical means to establish the extent of visual depression and to investigate the basis of rod dysfunction in this disorder. In acute disease with serous detachment of the retina, the loss of sensitivity attains 3 log units and parallels the height of retinal elevation as does its recovery with resolution of the episode. Immediately after resolution, there is a residual 0.5 log unit threshold elevation. In chronic disease, marked loss of function exists over areas of abnormal retinal pigment epithelium in the absence of clinically detectable serous detachment. Although rhodopsin levels are low in both acute and chronic CSR, this relative lack of visual pigment does not totally account for the functional deficits in either situation.

Fluorescein Angiography↗
PubMed1987

Management of the ageing macula.

Age-related Macular Degeneration (AMD) is responsible for the majority of registered blindness in the elderly. Laser photocoagulation can be offered as a treatment of proven value to only a proportion of patients with neovascular AMD. Clinically, our expectations must be tempered by the high incidence of recurrent subretinal vessels, the anatomic limitations of treatable lesions and the large number of ageing eyes for which there is no place for laser. In addition to improvements in education, referral habits and the application of laser therapy which may have an impact upon visual loss due to AMD, there are promising directions to be explored in alternative modes of treatment and prevention.

Aged↗
PubMed1985

Retinal lesions following long bone fractures.

Patients with long bone fractures are at risk for the fat embolism syndrome (FES). Although an estimated 50% of patients with overt FES have retinal abnormalities, the overall incidence of fundus lesions in patients with long bone fractures has not been studied. We examined 100 consecutive patients who had suffered long bone or pelvic fractures in the absence of head, abdominal, or thoracic injury, and who had no other diseases associated with retinopathy. Only one patient had visual symptoms. Cotton-wool spots and retinal hemorrhages were observed in four patients, none of whom were suspected of FES prior to our examination. Subclinical FES may be found by ophthalmoscopy in patients with long bone fractures.

Adolescent↗
PubMed1978

Studies on the mechanism of reduced urinary osmolality after exposure of renal papilla.

Studies were performed in Munich-Wistar rats to determine whether changes in papillary plasma flow might be responsible for the concentrating defect which occurs after exposure of the extrarenal papilla. Papillary plasma flow was measured by (125)I-albumin accumulation. Initial studies in hydropenic animals revealed that papillary plasma flow was 40% higher in the kidney with the exposured papilla, 41 vs. 29 ml/min per 100 g of papilla (P < 0.001). This increase in papillary plasma flow was detectable 15 or 45 min after removing the ureter. Because it was unclear whether the rise in papillary plasma flow was a cause or the result of the fall in urine osmolality, similar studies were performed in animals undergoing a water diuresis. In this setting, papillary plasma flow still increased on the exposed side compared to the control side, 81 vs. 60 ml/min per 100 g, despite similarly low urine osmolalities of 155 and 174 mosmol/kg, respectively. This finding is compatible with the possibility that papillary exposure per se causes an increase in papillary plasma flow and that this hemodynamic alteration may lead to a reduction in urinary osmolality secondary to washout of the medullary interstitium. A final group of hydropenic rats was given either indomethacin or meclofenamate before removing the ureter. In these studies, there was no difference in either the papillary plasma flow or the urine osmolality between control and exposed kidneys. It is therefore suggested that opening the ureter induces an increase in papillary plasma flow by some mechanism which may involve an alteration in prostaglandin synthesis.

Animals↗