A prospective study of dense spontaneous vitreous hemorrhage.

PURPOSE: We studied the incidence of vitreous hemorrhage in a well-defined population to determine the underlying causes of such hemorrhages. METHODS: We prospectively studied all eyes with dense spontaneous first-time vitreous hemorrhage during a 2 1/2-year period in the greater Göteborg area (542,000 inhabitants). Follow-up time was one year. RESULTS: Ninety-four patients (95 eyes) were included, corresponding to a yearly incidence of seven cases per 100,000 inhabitants. Because of demographic factors and the organization of Swedish ophthalmologic care, we believe that this is close to the true incidence. The cause of vitreous hemorrhage could be verified in all but four eyes but frequently not until late in the follow-up period. The most common underlying cause was vitreous detachment and traction to a retinal vessel (39 eyes). In 28 of these eyes a retinal tear was also present. Five of these eyes developed a retinal detachment. In 19 eyes, bleeding was caused by proliferative diabetic retinopathy. This figure was relatively smaller than in previous studies. Retinal vein occlusion was the cause of hemorrhage in 15 eyes. Retinal macroaneurysm (seven eyes) was an easily overlooked cause, often diagnosed late in the follow-up period. CONCLUSIONS: Because of the common diagnostic difficulties and the frequent need for laser treatment, vitrectomy, or both, it is recommended that eyes with vitreous hemorrhage be followed up in centers with ultrasonographic and surgical expertise.

Transillumination of iris and subnormal visual acuity--ocular albinism?

BACKGROUND: A common clinical sign in children with subnormal visual acuity or slow visual development was iris transillumination. This was used as the inclusion criterion in a study of children shown to have a subnormal visual acuity in a general health examination at age 4 years. METHODS: Refraction values, stereopsis, fundus photography, macular and nerve head appearance, and visual evoked response (VER) recordings were studied in 18 children. The clinical results were compared with 64 controls referred to the eye clinic because of subnormal vision from the general health examination or from school health care. RESULTS: Eight children had VERs showing asymmetry typical for albinism. Another four had only small asymmetries on the VER, indicating a lower degree of decussation abnormality. No simple correlation of visual acuity, degree of iris transillumination, stereopsis, or macular pathology and VER asymmetries were found. However, marked iris transillumination in all four quadrants, absence of a foveal reflex, and low visual acuity were weakly correlated. CONCLUSIONS: In a rather homogeneous group of children with iris transillumination and subnormal visual acuity eight of 18 had typical albino VERs. The findings of small atypical VER asymmetries in four children and no asymmetry in six children suggest that albinism may be considered as a description of a heterogeneous group of conditions including maximal decussation rate (100%) in the chiasma to a condition with almost normal (> or = 50%) decussation rate.

Non-stereo photographic screening after panretinal photocoagulation for proliferative diabetic retinopathy. Compared with 60D enhanced slit-lamp examination.

135 patients treated with panretinal photocoagulation for proliferative diabetic retinopathy were examined in order to detect 7 specific fibrovascular lesions after treatment. Two presumptive methods for long-term follow-up were evaluated and compared, i.e. slit-lamp biomicroscopy enhanced by a 60 D lens and reading from two non-stereo photographs of the posterior pole. Two observers repeated their examinations with respective methods. Comparison of the methods with respect to detecting ability of the fibrovascular lesions showed no significant disagreement except in some eyes with fibrous tissue on the optic disc where new vessels were better detected with the slit-lamp method (P less than 0.001). There was no difference between the methods with respect to the intra- and inter-observer variability. Twenty to 30 patients could be diagnosed per hour with the photographic method compared to 5-6 patients with the slit-lamp. Two non-stereo photographs of the posterior pole can be recommended as a safe and time-saving method for objective documentation and long-time follow-up after panretinal photocoagulation for proliferative diabetic retinopathy.

Low IGF-I suppresses VEGF-survival signaling in retinal endothelial cells: direct correlation with clinical retinopathy of prematurity.

Retinopathy of prematurity is a blinding disease, initiated by lack of retinal vascular growth after premature birth. We show that lack of insulin-like growth factor I (IGF-I) in knockout mice prevents normal retinal vascular growth, despite the presence of vascular endothelial growth factor, important to vessel development. In vitro, low levels of IGF-I prevent vascular endothelial growth factor-induced activation of protein kinase B (Akt), a kinase critical for endothelial cell survival. Our results from studies in premature infants suggest that if the IGF-I level is sufficient after birth, normal vessel development occurs and retinopathy of prematurity does not develop. When IGF-I is persistently low, vessels cease to grow, maturing avascular retina becomes hypoxic and vascular endothelial growth factor accumulates in the vitreous. As IGF-I increases to a critical level, retinal neovascularization is triggered. These data indicate that serum IGF-I levels in premature infants can predict which infants will develop retinopathy of prematurity and further suggests that early restoration of IGF-I in premature infants to normal levels could prevent this disease.