Does Type II Diabetes Predispose to Retinal Vein Occlusion?

Retinal vein occlusion (RVO) not infrequently occurs in diabetic patients. Although the aetiology is unclear, it could relate to the other microvascular complications of diabetes. In the non-diabetic, both the central (CRVO) and branch (BRVO) forms are commonly associated with hypertension and hyperlipidaemia. We have therefore studied fifty type II diabetic patients with RVO compared to a carefully matched diabetic control group (n = 50) to elucidate underlying medical conditions and hence the aetiology of RVO in diabetic patients. The two groups were well matched. Diabetics with RVO showed a strikingly high prevalence of hypertension compared to the controls (72% versus 32%: p < 0.001) and a trend to increased hyperlipidaemia (54% versus 36%). Diabetic microvascular complications were more common in the control group (diabetic retinopathy and proteinuria). No significant differences were observed in mean HbA1 or weight, but current smoking habits and blood pressure levels were increased in the diabetics with RVO. 80% of diabetic patients with the BRVO form, were hypertensive. We conclude that the main underlying medical conditions for RVO in diabetics are hypertension and hyperlipidaemia, and these may be important in the aetiology as in the non-diabetic. RVO is more common in type II rather than type I diabetes, and does not associate with the presence of diabetic microvascular complications. Clinical assessment for hypertension and hyperlipidaemia is therefore important in diabetic patients with RVO, especially if recurrence of the condition and further visual loss is to be prevented.

Use of oral fluorescein angiography in the diagnosis of macular oedema within a diabetic retinopathy screening programme

AIMS

To assess if oral fluorescein angiography (OFA) is a suitable screening method to detect macular oedema in diabetic retinopathy.

METHODS

Eighty-four diabetic patients were included in the study. They were from a consecutive series of patients attending the diabetic eye-screening clinic, with retinopathy at the macula requiring ophthalmology assessment. All patients were subsequently examined in the eye hospital, by ophthalmologist slit lamp biomicroscopy assessment as the gold standard, followed by oral fluorescein angiography.

RESULTS

This study indicates a sensitivity of 92% and specificity of 81%. Only 4.8% of patients developed a minor reaction to oral fluorescein; 84.5% of images were of good quality.

CONCLUSIONS

Oral fluorescein angiography is an efficient and highly sensitive tool for the detection of macular oedema. It can be used as an adjunct in the diabetic screening service to identify patients with oedema within a disc diameter of the macula. Ultimately it will ensure that only necessary and smaller numbers of patients are referred to ophthalmologists.

Nine year follow-up study of morbidity and mortality in retinal vein occlusion

PURPOSE

The aim of this study was to conduct a detailed retrospective follow-up of a large cohort of patients with retinal vein occlusion (RVO), examining morbidity and mortality, to investigate a possible relationship between RVO, large vessel disease and stroke, and to determine whether recurrence of RVO was influenced by treatment of associated medical conditions.

METHODS

A follow-up study was undertaken in 1994 of all patients (n = 588) who presented to the medical ophthalmology clinics of the Birmingham and Midland Eye Hospital between 1982 and 1989 with a definitive diagnosis of RVO.

RESULTS

Follow-up data were obtained on 549 patients (93%). Results showed that recurrence of RVO in the same or fellow eye was decreased by more than half in the follow-up group (3.3%) when compared with the known recurrence rate at initial presentation (8.8%). Comparison of the deceased with the survivors showed that the deceased patients were significantly older (mean age 70.2 vs 63.4 years). The prevalence of rubeosis iridis and smoking were statistically significantly increased when comparing the deceased with the survivors (p < 0.016 and p < 0.008 respectively). The deceased had a higher prevalence of diabetes (15.8% vs 10.1%), and there was a trend towards increased clinically evident macrovascular disease in those patients who had died (23.2% vs 19.5%). Neither hypertension nor hyperlipidaemia predicted death, as the prevalence rates of the two conditions were similar in survivors and those who had died (60.0% vs 60.6% and 48.4% vs 53.3%). The percentage of patients taking antiplatelet drug therapy was not different in the two groups (36.8% vs 38.3%). Analysis of the causes of death of the RVO population (n = 95) compared with the causes of death in the West Midlands population as a whole, showed that the percentage of deaths from myocardial infarction in the RVO population was significantly higher (23.1% vs 14.4%, p < 0.05). There was no statistical difference between the populations for ischaemic heart disease and stroke, although there was a trend for increased mortality from stroke (19% vs 13.5%).

CONCLUSION

These data suggest a relationship between RVO, mortality and increased cardiovascular risk factors (smoking, diabetes and macrovascular disease), and support the possibility of an association between RVO and stroke. They also support the potential value of medical treatment of underlying medical conditions in preventing recurrence of RVO.

Electrophysiological findings in Stargardt's-fundus flavimaculatus disease

PURPOSE

To determine the incidence of electrophysiological abnormalities in patients with Stargardt's-fundus flavimaculatus (STGD/FFM) disease.

METHODS

A retrospective review was carried out of the hospital records of 46 patients who had undergone a scotopic, single flash photopic and 30 Hz electroretinogram (ERG), pattern ERG (PERG) and electro-oculogram (EOG).

RESULTS

Patients were classified in two groups: those with flecks (n = 26) and those without flecks (n = 20). The incidence of abnormalities (amplitude and/or latency) for the two groups was: PERG, 90% and 98%; 30 Hz ERG, 55.8% and 50%; scotopic ERG, 38.5% and 27.5%; and single flash photopic ERG, 26% and 16%, respectively. EOG abnormalities occurred significantly more frequently in the group with flecks compared with the group without flecks: 69% and 42.5% respectively (p < 0.025). Furthermore, in the group with flecks the group mean scotopic ERG b-wave, 30 Hz ERG b-wave and PERG (P50) amplitude were significantly lower than in the group without flecks (p < 0.01).

CONCLUSIONS

The most consistent electrophysiological abnormality in STGD/ FFM is the reduction of the PERG. However, EOG, 30 Hz ERG, scotopic and photopic ERG abnormalities can also frequently occur. ERG and EOG abnormalities occur more often in the presence of flecks.

A 'fail-safe' screening programme for diabetic retinopathy

OBJECTIVE

To improve screening for diabetic retinopathy in a hospital diabetic clinic through the use of the audit process.

DESIGN

Comparison of an existing system of screening for diabetic retinopathy (a specialist optometrist using ophthalmoscopy alone) with a new system in which a specialist optometrist examined retinal Polaroid photographs taken through pharmacologically dilated pupils and combined this with ophthalmoscopy in all cases except when the photographs were perfect and definitely showed no retinopathy. In this new system, the optometrist could discuss cases of uncertainty with a diabetes physician while the patient was still in the clinic with eyes dilated.

SETTING

Inner city hospital diabetes clinic.

SUBJECTS

289 hospital diabetic clinic patients not already attending an ophthalmologist; a consecutive series of 144 such patients for the first audit, 145 for the repeat audit.

MAIN OUTCOME MEASURES

Assessment of each screening system against a gold standard. For the first audit this was agreement by two of four diabetes physicians, who combined examination of the photographs with the findings from dilated ophthalmoscopy, on the classification of the retinae of each patient, guided by standard European criteria. For the second audit, the gold standard was enhanced by discussing the photographs and findings of all patients with an independent ophthalmologist. For patients requiring referral, a second ophthalmologist also commented on the case.

RESULTS

The addition of retinal photography to universal pupil dilatation, and the availability of diabetes physician backup to discuss cases of uncertainty, greatly increased the optometrists' detection rate. Sensitivities for the first (ophthalmoscopy only) and second (ophthalmoscopy plus photography plus diabetologist back-up) audits were, respectively, 71.4% vs 100% for sight-threatening retinopathy, 33% vs 100% for retinopathy requiring six-month review, and 40.3% vs 97.2% for any retinopathy (p = 0.002).

CONCLUSIONS

Optometrists specialising in diabetic retinopathy using Polaroid retinal photography and ophthalmoscopy, both through dilated pupils, backed up by experienced diabetologists to discuss cases of uncertainty, could form the basis of a retinopathy screening service that accurately identifies and categorises retinopathy and does not miss sight-threatening cases.

Instant electronic imaging systems are superior to Polaroid at detecting sight-threatening diabetic retinopathy

Polaroid photography in diabetic retinopathy screening allows instant image availability to enhance the results of ophthalmoscopy. Retinal cameras are now being developed which use video/digital imaging techniques to produce an instant enlarged retinal image on a computer monitor screen. We aimed to compare one such electronic imaging system, attached to a Canon CR5 45NM, with standard Polaroid retinal photography. Two hundred and thirteen eyes from 107 diabetic patients were photographed through dilated pupils by both systems in random order and the images were analysed blind. Diabetic retinopathy was present in 58 eyes of which 55/58 (95%) were detected on the electronic image and only 49/58 (84%) on the Polaroid. Of 34 eyes requiring ophthalmologist referral according to standard European criteria, 34/34 (100%) were detected on the electronic image and only 24/34 (71%) on the Polaroid. Side by side comparisons showed electronic imaging to be superior to Polaroid at lesion detection. Using linear analogue scales, the patients assessed the electronic imaging photographic flash as less uncomfortable than the Polaroid equivalent (p < 0.0001). Other advantages of electronic imaging include: ready storage of the images with other patient clinical data on the diabetes computerized register/database; potential for image enhancement and analysis using image analysis software and electronic transfer of images to ophthalmologist or general practitioner. Electronic imaging systems represent a potential major advance for the improvement of diabetic retinopathy screening.

Posterior scleritis and polymyalgia rheumatica

Scleritis is typically a non-infectious granulomatous inflammatory process. It may be found in conjunction with systemic disease, more commonly in those patients with necrotising anterior scleritis. We describe a patient with posterior scleritis and polymyalgia rhematica. This association has not previously been reported.

Diabetic eye disease: a natural history study

In previous studies on diabetic retinopathy it has not been possible to relate risk factors to reduced vision because of the influence of vision-preserving treatment. Demographic data, cardiovascular risk factors and ocular features from the diabetic population of the Seychelles are described. Diabetic retinopathy in this population had not been modified by laser treatment. The population described consists of entirely type 2, maturity onset diabetics. Using a multivariate logistic regression model, the risk factors were deduced for three outcome variables: (1) reduced vision, defined as 6/36 or worse in both eyes; (2) the presence of diabetic retinopathy; and (3) the presence of maculopathy, preproliferative and proliferative retinopathy, grouped as severe retinopathy. Insulin treatment was associated with all outcome variables, duration from diagnosis of diabetes with retinopathy of all forms, and increasing age with reduced vision and severe retinopathy. Hypertensive diabetic patients were twice as likely to have reduced vision as compared with non-hypertensive diabetic individuals.

Sex hormone preparations and retinal vein occlusion

Retinal vein occlusion (RVO) is most commonly seen in middle-aged or older patients and is associated with underlying cardiovascular risk factors. It is much less common in younger patients. Use of the oral contraceptive pill (OCP) is known to be a risk factor for cardiovascular and cerebrovascular disease. There have previously been a few isolated case reports of patients sustaining an RVO whilst taking the OCP. The aim of this study was to investigate patients sustaining an RVO whilst taking the OCP or hormone replacement therapy (HRT). From a large series of 588 patients, we found 11 with an RVO associated with sex hormone preparations. Of these, 6 had taken the OCP and 5 were HRT users. From this large group there were only 9 female patients aged under 35 years who sustained an RVO. Of these, 6 were associated with use of the OCP. All patients were investigated for recognised medical risk factors for RVO. None of these factors were identified in the patients who had used the OCP. Of the patients taking HRT, 4 of the 5 had other potential risk factors. From our large series, the prevalence of RVO in female patients under 35 years taking the OCP was 66%. There is a 30% uptake of the OCP in the general population. These data support the view that RVO is a contraindication to the use of the OCP. Additionally, it would appear (albeit from limited data) that patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.

Imaging of optic disc drusen: a comparative study

The choice of imaging technique to identify the presence of optic disc drusen has not been well established. We performed computed tomography (CT), magnetic resonance imaging (MRI), fundus fluorescein angiography and B-mode ultrasonography (B-USG) on four patients with optic disc drusen as the sole identifiable pathological process. CT, MRI and examination for autofluorescence demonstrated the presence of drusen in only one case each. B-USG showed characteristic features of optic disc drusen in all cases. We suggest that B-USG, a non-invasive and inexpensive technique, may be the imaging method of choice in identifying the presence of disc drusen.

Dye enhanced laser photocoagulation in the treatment of a peripapillary subretinal neovascular membrane

A 45-year-old female with an elevated peripapillary subretinal neovascular membrane was treated with dye enhanced laser photocoagulation, using indocyanine green and the diode laser. Following treatment the membrane regressed, with flattening of the lesion. No side effects occurred and excellent visual acuity was maintained over a 12 month follow-up period.

Are there medical conditions specifically underlying the development of rubeosis in central retinal vein occlusion?

Two hundred and thirty five patients with central retinal vein occlusion (mean age 64.9 years, 95% CI (63.3, 66.5) years), comprising 221 white Europeans, 10 Asians and 4 West Indians) were studied over a 7 year period of whom 13.2% (n = 31) developed rubeosis (mean age 70.1 years, 95% CI (66.3, 73.9) years; all white Europeans). Comparisons were made with 31 of the original 235 CRVO patients who did not develop rubeosis, and who were individually matched for age, sex and ethnic origin. The 31 patients developing rubeosis were significantly older (p = 0.013) than the 204 patients not developing rubeosis (mean age 64.1 years, 95% CI (62.3, 65.9) years). There was no significant difference between the CRVO group with rubeosis and the uncomplicated matched CRVO group in the prevalence rates of hypertension (64.5% vs. 45.2%), hyperlipidaemia (48.4% vs. 38.7%) or diabetes mellitus (9.7% vs. 12.9%). We conclude that neovascular glaucoma is more likely to occur in older subjects with CRVO.

Management of retinal vein occlusion

Retinal vein occlusion is a common cause of visual loss. The clinical features, pathogenesis, aetiology and management of this condition are presented and discussed. It is an advantage to involve both the physician and the ophthalmologist in the management of the condition.

Diabetes mellitus and retinal vein occlusion in patients of Asian, west Indian and white European origin

The incidence of retinal vein occlusion (RVO) is known to be related to several cardiovascular risk factors including diabetes mellitus, hypertension and hyperlipidaemia. We have assessed the prevalence of these risk factors in Caucasian (N = 536, mean age = 65.21 years), West Indians (N = 24, mean age = 57.3 years) and Asian (N = 28, mean age = 51.4 years) patients presenting with RVO. We found no significant differences between the three groups in the distribution of hyperlipidaemia, but diabetes mellitus was more common amongst both the Asians and W. Indians (10% v 29% and 38%, p < 0.01 and p < 0.001). Hypertension was also more common in both the Asians and the West Indians (59% v 64% and 83% m p < 0.001 and p < 0.0001). The Asians and West Indians presenting with RVO were significantly younger and had significantly higher body mass index than their Caucasian counterparts (Ethnic origin, BMI, mean age: Asian, 28.1 +/- 4.3, 51.5 +/- 12.3 years; West indian: 30.2 +/- 7.7, 57.3 + 10 years; White: 24.8 +/- 4.2, 65.2 +/- 11.4 years). In this study RVO occurred at a younger age in Asians and West Indians, and was associated with a greater prevalence of diabetes mellitus and hypertension. The prevalence of hyperlipidaemia was no different in the three groups.

Electroretinography as a prognostic indicator or neovascularisation in CRVO

A prospective study was carried out to compare the efficacy of electroretinography, fundus fluorescein angiography and clinical examination in identifying those at risk of rubeotic glaucoma following central retinal vein occlusion (CRVO). Our preliminary observations are described. The findings suggest a complementary role for electroretinography in the management of CRVO. Particularly significant were interocular differences in 30 Hz flicker latency, the ability to elicit pattern ERGs and the ratio of scotopic and photopic a:b wave amplitudes. Of the clinical measures the depth of the relative afferent pupil defect was a sensitive indicator of rubeosis. Factors of lesser statistical prognostic value included poor visual acuity and the extent of deep retinal haemorrhages. Fundus fluorescein angiography in this study had limited value in predicting those patients at risk of rubeosis.

Randomised blind controlled trial of a high fibre, low fat and low sodium dietary regimen in mild essential hypertension

Thirty-four patients with essential hypertension were allocated, in a controlled trial, to a treatment diet of high fibre, low fat and low sodium composition, or to a control diet by the hospital dietitian. Clinical observations were made by a separate 'blinded' nursing sister. After three months treatment, the modified diet-treated group showed a significant reduction in mean systolic (169.4 +/- 23.4 to 150.6 +/- 16.1 mmHg) and diastolic blood pressure (101.5 +/- 7.3 to 89.4 +/- 6.8 mmHg), accompanied by significant reductions in urinary sodium excretion (140.4 +/- 34.6 to 93.7 +/- 44 mmol/day) and weight (73.1 +/- 10 to 71.2 +/- 8.4 kg). The changes in control were; systolic 171.2 +/- 14.1 to 162.1 +/- 19.5 mmHg and diastolic pressure 97.2 +/- 10.8 to 91.7 +/- 9.7 mmHg. The mean differences in reductions between treated and control were 8.8 mmHg Systolic (95% confidence intervals: -2.6 to 21.2 mmHg) and 7.0 mmHg diastolic blood pressure (95% confidence intervals: 0.4 to 14.4 mmHg). The number of patients with normal blood pressure in the diet treated group at three months was double that in the control (eleven versus five). No relationships were shown between blood pressure changes and those of weight or urinary sodium excretion during the trial. The findings in this study are broadly in agreement with similar ones in essential hypertension and suggest that this form of dietary regimen has a clinically worthwhile hypotensive effect and this should be readily achievable in routine clinical practice.

Ocular toxicity of desferrioxamine--an example of copper promoted auto-oxidative damage?

Three patients with rheumatoid disease were given the 'iron chelating' drug desferrioxamine (DFX), which also has an appreciable affinity for copper. The drug was injected cautiously, in lower doses than in patients with thalassaemia, and intramuscularly to evaluate its anti-inflammatory effects. Two of the three patients developed ocular abnormalities. One patient, who also received methyldopa, developed severe but reversible visual failure associated with an abnormal electro-oculogram (EOG); another showed reversible depression of the EOG. Analysis of the cerebrospinal fluid (CSF) of this patient showed an increase in phenanthroline detectable (non-caeruloplasmin-bound) copper. Analysis of the CSF of the third patient, who did not develop any clinical or electrophysiological ocular abnormalities, was normal. Haematological assessments indicated that all three patients probably had reduced iron stores. With in-vitro systems DFX was shown to mobilise copper from albumin and to facilitate copper movement across a cell membrane model, a property that was enhanced by methyldopa. Our observations are consistent with the concept that in rheumatoid patients low iron stores may result in binding of copper by DFX and that this may be of central importance in causing the ocular toxicity of DFX.

Medical conditions underlying recurrence of retinal vein occlusion

Seventeen patients with recurrent retinal vein occlusion were investigated for underlying medical conditions and compared with 61 patients with single retinal vein occlusion (26 with central, 35 with branch vein occlusion). The two study groups were comparable for age, sex, and weight. Patients with recurrence had a significantly increased prevalence rate of hypertension (88% versus 48%: p less than 0.01), with a trend to increased hyperlipidaemia (47% versus 33%) compared with patients with a single episode. A significantly raised mean systolic (p less than 0.05) but not diastolic blood pressure was found in patients with recurrence. Other cardiovascular risk factors in patients with recurrence were also found and included lower mean levels of high density lipoprotein (HDL)-cholesterol (p less than 0.02) and the HDL2 subfraction (p less than 0.001), and a significantly increased proportion of patients with regular alcohol intake (p less than 0.01). We conclude that hypertension and hyperlipidaemia with an increase in other cardiovascular risk factors are commonly found in patients with recurrent retinal vein occlusion and may therefore be important aetiological factors. The possible benefits of treatment of these underlying conditions to prevent recurrence need to be assessed in well designed prospective studies.

Permeability of blood-retinal barriers in urethane-induced rat retinopathy: a fluorescein angiographic, vitreous fluorophotometric, and fluorescence microscopic study

Urethane-induced rat retinopathy, characterised by permeability abnormalities of the blood-retinal barriers (BRB), was studied during the developmental phases by fluorescein fundus angiography (FFA), vitreous fluorophotometry (VF), and fluorescence microscopy (FM). A distinction based on VF values could be made at the p less than 0.02 confidence level between the retinopathic rats as a group and the control rats. Fluorescence microscopy provided a basis, however, for subdividing the test group into those rats with evidence of intraretinal leakage of NaFl and those without. Statistical analysis of the VF values of the control (A), nonleaky retinopathic (B), and leaky retinopathic (C) rats showed no significance between groups A and B, but highly significant differences between groups A and C (p less than 0.001) and between groups B and C (p less than 0.01). Fluorescence microscopy also showed that leakage of NaFl from retinal vessels occurred only after the retinopathy has progressed to the point where retinal vessels had become incorporated into the pigment epithelium. We conclude from this fluorescent marker clinicopathological study that breakdown of the blood-retinal barriers is a result of an interaction between the retinal pigment epithelium (RPE) and the retinal vessels after the vessels become incorporated into the RPE.

Long-term morbidity of herpes zoster ophthalmicus

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