Faculty Bibliography

PURPOSE: To determine if peroxidized lipids occur in Bruch's membrane isolates and to characterize the type present in human necropsy specimens. METHODS: Bruch's membrane isolates from eye bank eyes obtained from 13 white donors were homogenized. Measurement of peroxidized lipids was done with the fluorometric thiobarbituric acid assay and high pressure liquid chromatography. RESULTS: Bruch's membrane isolate homogenates contained native unsaturated fatty acids and peroxidized lipids in a ratio of about 200:1. The amount of thiobarbituric acid reacting substances increased exponentially with age. The peroxidized lipids identified in Bruch's membrane isolates were derived from long chain polyunsaturated fatty acids, particularly docosahexaenoic acid and linolenic acid, which are normally found in the photoreceptor outer segments. CONCLUSIONS: Lipids are known to accumulate in Bruch's membrane, an acellular layer with no known intrinsic mechanisms to combat lipid peroxidation. In related studies, lipid peroxides have been shown to induce neovascularization by inducing expression of a cascade of angiogenic cytokines. This is the first study to show that lipid peroxides, biological molecules that have the potential to incite new vessel growth, occur in Bruch's membrane. The increase in amount of peroxidized lipids with age, combined with their vasogenic potential, suggests that peroxidized lipids may play a role in the etiology of age-related macular degeneration, particularly choroidal neovascularization

OBJECTIVE: Recent studies have shown that indocyanine-green videoangiography (ICG-V) is useful to image occult choroidal neovascularization. The authors studied the ICG-V findings in fellow drusen eyes of patients with unilateral exudative age-related macular degeneration (AMD). The authors also studied the occurrence of exudative changes to determine whether ICG-V is useful in predicting future exudative changes in these eyes with only drusen. DESIGN: Cohort study. PARTICIPANTS: The authors studied 432 consecutive patients diagnosed with unilateral exudative AMD in whom the fellow eye had only drusen by clinical fundus examination and fluorescein angiography. All of these eyes had ICG-V performed. Follow-up data were obtained in all eyes with abnormal indocyanine-green (ICG) angiograms and randomly sampled ICG angiograms of normal eyes. MAIN OUTCOME MEASURES: The initial ICG findings were classified as showing normal or abnormal hyperfluorescence. Abnormal hyperfluorescence eyes were subdivided into focal spots (focal areas of hyperfluorescence < 1 disc area in size) and plaques (areas of hyperfluorescence > 1 disc area). The development of exudative changes in eyes with normal and abnormal hyperfluorescence was compared. RESULTS: Of the 432 fellow eyes, 386 (89%) eyes with drusen had a normal ICG-V study, whereas 46 (10 focal spots and 36 plaques) (11%) eyes had an abnormal ICG-V. Exudative changes occurred in 6 (10%) of 58 normal ICG eyes and 9 (24%) of 38 eyes with abnormal ICG findings during a mean follow-up period of 21.7 months. The difference between drusen eyes with normal ICG angiograms and those with plaques on ICG-V regarding future exudative changes (10% vs. 27%, respectively) was statistically significant (P = 0.038). CONCLUSIONS: Abnormal ICG findings were found in 11% of eyes with clinically and fluorescein angiographically nonsuspicious drusen. The subgroup of patients with plaques on ICG-V had a higher chance of having exudative changes develop. Indocyanine-green videoangiography may be a predictive indicator of future exudative changes in eyes with drusen. A much larger prospective study seems justified

OBJECTIVE: The authors evaluated the clinical, fluorescein, and indocyanine green (ICG) angiographic characteristics of the macular variant of idiopathic polypoidal choroidal vasculopathy (IPCV). DESIGN: Observational case series. PARTICIPANTS: The records, photographs, and fluorescein and ICG angiograms of eight eyes of seven patients with IPCV lesions confined to the macula were reviewed. MAIN OUTCOME MEASURES: The visual acuity, fundus examination, fluorescein and ICG angiographic characteristics, and clinical course were compared. RESULTS: All patients demonstrated polypoidal lesions arising from macular choroidal vessels on ICG angiography. One patient had bilateral lesions. These lesions appeared hyperfluorescent in the early phases of both fluorescein and ICG angiography. Late-phase leakage was seen in cases associated with subretinal fluid or exudate. None of these patients demonstrated polypoidal lesions arising from the peripapillary choroidal circulation or peripapillary choroidal neovascularization. Three eyes with polypoidal lesions that were associated with subretinal fluid and exudates were treated with photocoagulation. Five eyes were not treated. Final visual acuity ranged from 20/20 to hand motions. Severe visual loss was associated with vitreous and subretinal hemorrhage, but this resolved without permanent severe visual loss in several cases. CONCLUSIONS: In the macular variant of IPCV, ICG and fluorescein angiography demonstrate characteristic macular polypoidal lesions without evidence of peripapillary lesions. The vascular origin of these polypoidal lesions appears to be the macular choroidal circulation. This is distinguished from classic IPCV, in which lesions appear to arise from the peripapillary choroidal circulation. Visual prognosis appears to be good, with most patients retaining visual acuity of 20/80 or better. If subretinal fluid or exudates reduce visual acuity, photocoagulation should be considered

OBJECTIVE: This study aimed to use a new technique for ocular imaging, digital subtraction indocyanine green angiography (DS-ICGA), to evaluate patients with occult choroidal neovascularization (CNV). DESIGN: The design was a cross-sectional study of patients with occult CNV. PARTICIPANTS: A total of 31 eyes of 31 patients were studied. INTERVENTION: Digital subtraction of sequentially acquired indocyanine green angiographic frames was used to image the progression of the dye front in eyes with occult CNV. A method of pseudocolor imaging of the choroid was developed that allows differentiation and identification of underlying choroidal arteries and veins. RESULTS: The DS-ICGA of occult CNV showed consistent findings. Occult CNV was imaged with greater detail and in a shorter period of time than with conventional indocyanine green angiography. The fundus landmarks were retained with DS-ICGA much better than with conventional indocyanine green angiography. CONCLUSIONS: The DS-ICGA uses time to dissect the choroidal circulation. With DS-ICGA, occult CNV could be imaged more quickly and in greater detail than with conventional imaging techniques. The DS-ICGA may improve the authors ability to image, and subsequently treat, occult CNV