Niels Vesti Nielsen

Prevalence and causes of visual impairment according to World Health Organization and United States criteria in an aged, urban Scandinavian population: The Copenhagen City Eye Study

PURPOSE To evaluate the prevalence and causes of visual impairment in an epidemiologic study of aged, urban individuals in Denmark. DESIGN Cross-sectional study. PARTICIPANTS The study population consisted of 1000 randomly selected residents aged 60 to 80 years in Copenhagen, Denmark. Of 976 eligible persons, 946 (96.9%) could be examined. Information about best-corrected visual acuity (VA) was obtained from 944 cooperative persons (96.7%). METHODS Data from the Copenhagen City Eye Study were used to assess the cause-specific prevalence of visual impairment as defined by the World Health Organization (WHO) (VA worse than 20/60-20/400 in the better eye) and the criteria used most commonly in the United States (VA worse than 20/40 but better than 20/200 in the better eye). Eligible subjects underwent an extensive ophthalmologic examination at The National University Hospital of Denmark. MAIN OUTCOME MEASURES Best-corrected VA and primary causes of visual impairment. RESULTS The prevalence of low vision according to the WHO definition ranged from 2.6% in subjects aged 70 to 74 years to 4.8% in subjects 75 to 80 years of age, with an age-adjusted relative prevalence of 1.58%. Using the U.S. definition, the overall age-adjusted prevalence of visual impairment was 2.9%. The causes of visual impairment according to the WHO criteria were age-related macular degeneration (AMD) (44.4%), cataract (33.3%), glaucoma in combination with cataract (11.1%), myopic macular degeneration (5.6%), and diabetic retinopathy (5.6%). However, according to the U.S. criteria, cataract was the most frequent primary cause (50.0%) and AMD was the second most frequent primary cause (34.4%) of visual impairment. Furthermore, using the U.S. criteria diabetic retinopathy was revealed as equally important as AMD and cataract as a cause of visual impairment among persons aged 65 to 69 years (33.3%). CONCLUSIONS Increasing age was an independent predictor of visual impairment. Cataract and AMD were the leading causes. Adequate implementation of surgery to treat cataract could reduce visual impairment by 33.3% according to the WHO criteria and by 50% according to the U.S. criteria.

RETINOPATHY CAUSED BY TREATMENT WITH TAMOXIFEN IN LOW DOSAGE

In 17 patients treated with tamoxifen in a low dosage (30 mg daily) ophthalmological examination was performed. This revealed 2 cases with possible retinotoxic effect. A 64 year‐old woman treated with tamoxifen for 9 months for metastatic breast cancer developed retinopathy with transitory visual impairment. The retinopathy was morphological characterised by multiple yellowish‐white dots in the posterior pole, a parafoveal haemorrhage and accumulation of reticular pigment changes in the periphery of the retina. By retinal fluorescein angiography multiple non‐fluorescent dots and hyperfluorescent areas were seen in the posterior pole. The retinal lesions remained unchanged except for the haemorrhage after discontinuation of the tamoxifen treatment. In another patient some of these changes were also found. The retinotoxic effect of tamoxifen has been reported previously with tamoxifen in high dosage (≥ 180 mg daily, minimal total dosage of 90 g) used for long periods, but never from this drug in low dosage (30 mg daily, minimal total dose 8.1 g‐12.0 g).

Diabetic retinopathy I. The course of retinopathy in insulin-treated diabetics. A one year epidemiological cohort study of diabetes mellitus. The Island of Falster, Denmark.

The course of diabetic retinopathy was investigated in 215 out of 227 insulin‐treated diabetics in a one year epidemiological cohort study. Twelve diabetics, all with an onset age ≥ 30 years, could not be re‐examined due to deaths in 11 diabetics and deny in 1 diabetic. At the one year follow‐up no change (P > 0.10) occurred in the prevalence of background retinopathy (50.0% vs 51.6%) or of proliferative retinopathy (16.3% vs 18.6%). The one year incidence of newly developed background retinopathy was 3.7% and of deteriorated retinopathy 10.7%. Newly developed proliferative retinopathy was found in 2.3 % of the diabetics after one year. Deterioration of pre‐existing background retinopathy developed most frequently among diabetics with a diabetes duration above 10 years. Deterioration of both background retinopathy and proliferative retinopathy showed a sudden onset in some diabetics. Partial sight and legal blindness caused by diabetic retinopathy developed in 3.7% of the diabetics, respectively.

TIMOLOL TRANSITORY MANIFESTATIONS OF DRY EYES IN LONG TERM TREATMENT

In 64 patients treated with timolol eye drops (0.25% and 0.50%) seven patients developed transitory sensation of dry eyes. Two of these subjects also had xerostomia. Conjunctival and corneal defects were disclosed simultaneously with rose bengal staining. Morphologically, some of these lesions might have the same appearance as of the early stages of kerato‐conjunctivitis sicca. A reduction of Schirmer test and break‐up time was noted. The duration of symptoms ranged from 3 to 13 days. The mean time of treatment at the début of symtoms was 30 weeks (range 23–43 weeks). A pathogenesis of these seemingly harmless findings is at the present obscure.

The concentration of lysozyme and secretory IgA in tears from healthy persons with and without contact lens use

Abstract. A comparison of tear lysozyme and tear secretory IgA, determined by micropipette sampling and immunoassay technique, between 18 long‐term contact lens wearers (median age 35 years, median lysozyme concentration 1.93 g/l, median IgA concentration 0.72 g/l) and 42 non‐contact lens wearers (median age 41 years, median lysozyme concentration 2.21 g/l, median IgA concentration 2.42 g/l) disclosed a significant decrease (P < 0.01) of secretory IgA in the contact lens group. The decrease of secretory IgA was associated (P < 0.01) with the presence of deposits on lens surface. No differences in lysozyme concentration was found between the two groups (P > 0.05). The duration of lens wear was 8.5 years in average ranging from 1 to 23 years. These findings of decreased secretory IgA might partly explain the fact that contact lens wearers are more exposed to infectious corneal and conjunctival complications than non‐contact lens wearers.

OCULAR HYPERTENSION. A 15-YEAR FOLLOW-UP

A group of 55 subjects with ocular hypertension were followed‐up after 15 years. They were detected at a glaucoma screening on the island of Falster between 2031 volunteer blood donors, and they had an applanation pressure of ≧ 20 mmHg in one or both eyes. All the subjects were traced. Nine have died, all from general causes, and one of the deceased subjects was treated for simple glaucoma. Of the remaining 46 living subjects, 3 developed glaucomatous visual field defects despite treatment. In another 4 subjects anti‐glaucoma treatment was felt to be indicated. Of the non‐treated 39 living subjects, 20 had a decreased applanation pressure, well below 20 mmHg, and 19 had an unaltered applanation pressure. We found that neither the common blood groups nor a water provocative test performed in 1962 were of any help in predicting glaucomatous visual field defects. Central corneal thickness measurements performed in 1977 could not allocate the subjects to the groups simple glaucoma, applanation pressure > 20 mmHg or ≦ 20 mmHg.

Timolol. Hypotensive effect, used alone and in combination for treatment of increased intraocular pressure.

In 43 persons with increased intraocular pressure (IOP) Timolol maleate eye drops (0.25 % and 0.5 %) were used as a single and combined treatment. A significant decrease in IOP was noticed in 34 persons (P < 0.001) initially. No diminished effect of treatment was apparent after 9 weeks in 34 subjects or after 15 weeks in 23 subjects with Timolol alone. In nine persons with high IOP, Timolol had a significant (P < 0.001) but insufficient lowering effect. Epinephrine (1 %) and acetazolamide appeared to have an additive effect in these cases. No serious local or systemic adverse effects were discovered.

Corneal sensitivity and vibratory perception in diabetes mellitus.

36 patients suffering from diabetes mellitus and 45 controls were subjected to blind studies for corneal sensitivity using Cochet & Bonnets aesthesiometer and of vibratory perception of the left index finger and great toe by biothesiometer. 83 per cent of the diabetics had a corneal sensitivity below 60 mm against 38 per cent of the controls. Likewise a significantly reduced vibratory perception was noticed among the diabetics. Further, the reductions of corneal sensitivity and vibratory perception were correlated in the diabetics. In both groups falling corneal sensitivity and vibratory perception were found with increasing age over and above 50 years.

The prevalence of glaucoma and ocular hypertension in type 1 and 2 diabetes mellitus. An epidemiological study of diabetes mellitus on the island of Falster, Denmark.

The prevalence of glaucoma and ocular hypertension was investigated in an epidemiological study of diabetics traced by registration of prescriptions on insulin and oral hypoglycaemic agents (OHA) on the island of Falster (inhabitants 44 498), Denmark. Among 533 diabetics (227 insulin‐ and 306 OHA‐treated) the prevalence rate of primary open angle glaucoma and ocular hypertension was 6.0% and 3.0%, respectively. Neovascular glaucoma occurred in 2.1% of all diabetics and in 21.3% of diabetics with proliferative retinopathy. Open angle glaucoma was more prevalent (P < 0.01) in type 2 diabetes mellitus compared with type 1 diabetes mellitus. No difference in the prevalence of neovascular glaucoma was found between type 1 and type 2 diabetics. The occurrence of open angle glaucoma correlated positively (P < 0.01) to the current age (> 65 years) in both groups and the diabetes onset age (> 40 years) in insulin‐treated diabetics. Neovascular glaucoma correlated positively (P < 0.05) with diabetic macrovascular complications in total (myocardial infarction, ischemic heart disease, arterial hypertension, cerebrovascular stroke, gangrene/amputation), neuropathy and severe microvascular complications (proliferative retinopathy, retinovascular occlusion). Diabetics with open angle glaucoma and ocular hypertension showed a higher frequency (P < 0.05) of ischemic heart disease, arterial hypertension and retinovascular occlusion compared with diabetics without glaucoma or ocular hypertension.

The prevalence and causes of impaired vision in diabetics. An epidemiological study of diabetes mellitus on the island of Falster, Denmark.

The prevalence of partial sight and legal blindness was studied in 533 diabetics traced by prescriptions on insulin and oral hypoglycaemic agents (OHA) on the island of Falster (44 498 inhabitants). The prevalence of insulin‐treated diabetics (30 September 1980) was 0.52 per 1000 inhabitants and 0.72 per 1000 inhabitants of OHA‐treated patients. In the insulin‐treated group 106 patients had an onset age of diabetes below 30 years. Legal blindness occurred in 7.9% of 227 investigated insulin‐treated and in 4.9% of 306 OHA‐treated patients. Thus, the overall frequency of blindness in these 533 investigated diabetics was 6.2%. Partial sight was found in 4.9% of insulin‐treated and in 10.5% of OHA‐treated diabetics. In the insulin‐treated patients partial sight and legal blindness was caused by retinopathy (background and proliferative) in 81.8% and 84.8% of patients, respectively. Retinopathy contributed to partial sight in 46.8% and legal blindness in 80% of OHA‐treated diabetics. Proliferative retinopathy and background retinopathy caused visual loss in 48.4% and 36.4%, respectively, of legal blind diabetics. In diabetics with partial sight, background retinopathy was a more frequent cause of impaired vision (44.2% of the patients) than proliferative retinopathy (9.3% of the patients). In 50% of OHA‐treated patients with partial sight maculopathy without diabetic retinopathy (senile maculopathy) was the cause of visual impairment in contrast to 1% of insulin‐treated patients with partial sight. The severity of visual impairment was significantly associated with the duration of diabetes (> 15 years), the current age (> 50 years) and age at onset of diabetes (> 30 years) in insulin‐treated group. Relation between duration of diabetes (> 5 years) current age (> 70 years) and a visual acuity 0.10 could be demonstrated in OHA‐treated patients. Impaired vision was more common among females in both the insulin‐ and OHA‐treated group. In the females no association appeared between the frequency of pregnancies and a visual acuity 0.33. In diabetics with nephropathy, gangrene or amputation impairment of vision occurred more frequently.