Late-phase Indocyanine Green Angiography Research Articles

Choroidal Thickness, Vascular Hyperpermeability, and Complement Factor H in Age-Related Macular Degeneration and Polypoidal Choroidal Vasculopathy

To investigate the relationship between subfoveal choroidal thickness, choroidal vascular hyperpermeability, and complement factor H (CFH) gene polymorphism in typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV). Fifty-eight patients with typical AMD and 63 patients with PCV underwent fluorescein angiography, indocyanine green angiography (IA), and spectral-domain optical coherence tomography (OCT) using enhanced depth imaging (EDI). Subfoveal choroidal thickness was measured using EDI-OCT images, and choroidal hyperpermeability was evaluated using late-phase IA images. The major AMD-associated single-nucleotide polymorphisms were genotyped in 86 patients. Mean subfoveal choroidal thickness was significantly lower in eyes with typical AMD than that in eyes with PCV (P = 0.025). Subfoveal choroidal thickness was greater in eyes with choroidal hyperpermeability than that in eyes without it in typical AMD (P < 0.001) and PCV (P = 0.020), and in the fellow eyes of typical AMD (P < 0.001) and PCV (P = 0.027). In eyes without choroidal hyperpermeability, the mean subfoveal choroidal thickness was greater in PCV than that in typical AMD (P = 0.001). Choroidal thickness decreased after photodynamic therapy combined with intravitreal ranibizumab in typical AMD (P = 0.016) and PCV (P = 0.036). In eyes with PCV, the I62V polymorphism in the CFH gene contributed to choroidal thickness (P = 0.043). Choroidal thickness is related to the AMD subtypes, choroidal hyperpermeability, and I62V CFH gene polymorphism. In eyes without choroidal hyperpermeability, EDI-OCT is useful as an auxiliary measure for differentiating typical AMD and PCV.

USEFULNESS OF INDOCYANINE GREEN ANGIOGRAPHY TO DEPICT THE DISTANT RETINAL VASCULAR ANOMALIES ASSOCIATED WITH BRANCH RETINAL VEIN OCCLUSION CAUSING SEROUS MACULAR DETACHMENT

To report the usefulness of indocyanine green angiography (ICGA) to depict the retinal vascular anomalies associated with distant branch retinal vein occlusion resulting in serous retinal detachment at the macula. This was a retrospective, case series of 6 patients (6 eyes) with serous retinal detachments. Fluorescein angiography and ICGA showed that those 6 eyes had a distant branch retinal vein occlusion. The characteristics in ophthalmic examinations such as fundus appearance, fluorescein angiography, ICGA, optical coherence tomography, and clinical courses were evaluated. In addition to serous retinal detachments, five eyes exhibited hard exudates around the macula. Fluorescein angiography and ICGA clearly showed the vessel occlusion; however, no apparent abnormalities appeared in the macular area in any of the eyes. In four eyes, early-phase ICGA depicted the retinal vascular anomalies within the area of venous occlusion and those were seen as hyperfluorescent patches on late-phase ICGA. In two eyes, punctate hyperfluorescent spots were seen in the area of venous occlusion on late-phase ICGA. Optical coherence tomography depicted a serous retinal detachment at the macula and retinal swelling in the outer nuclear layer from the macula to the hyperfluorescent abnormalities on ICGA. The macular serous retinal detachments were resolved within 3 months after laser photocoagulation was applied to the hyperfluorescent areas on ICGA. Leakage from subsequent vascular anomalies after branch retinal vein occlusion can cause submacular fluid. Indocyanine green angiography is useful for detecting the causative vascular regions of the fluid.

Diagnostic Evaluation of Type 2 (Classic) Choroidal Neovascularization: Optical Coherence Tomography, Indocyanine Green Angiography, and Fluorescein Angiography

To evaluate the diagnostic characteristics of type 2 (classic) choroidal neovascularizations secondary to age-related macular degeneration using spectral domain-optical coherence tomography (SD OCT), indocyanine green angiography (ICGA), and fluorescein angiography (FA). Observational case series. Institutional. Thirteen treatment-naïve eyes with type 2 choroidal neovascularization without an occult component. Greatest horizontal dimension, based on the anatomic features of the neovascular complex by SD OCT (Spectralis; Heidelberg Engineering), ICGA, and FA; retinal leakage area in late-phase FA and ICGA; and the area of retinal edema in SD OCT. For direct comparison, ICGA and FA images were overlaid manually on infrared plus SD OCT images using VirtualDub and Paint.NET software. Greatest horizontal dimension was measured using Image J software (National Institutes of Health). The mean greatest horizontal dimension of the neovascular complex and the retinal leakage area consistently were smaller on ICGA compared with the area of retinal edema on SD OCT. According to FA, the greatest horizontal dimension of early, well-demarcated hyperfluorescence was significantly smaller than the neovascular complex on SD OCT. In addition, the greatest horizontal dimension of the retinal leakage area in late-phase FA consistently was smaller than the area of retinal edema on SD OCT. In classic choroidal neovascularization, ICGA and FA seem to underestimate the extension of the neovascular complex and the associated retinal pathologic features compared with SD OCT imaging.

Centrifugal Fundus Abnormalities in Pseudoxanthoma Elasticum

To investigate the Bruch's membrane-retinal pigment epithelium (RPE) complex in pseudoxanthoma elasticum (PXE) by imaging techniques capable of visualizing deep retinal structures with high contrast. Prospective cross-sectional study. Patients with PXE, confirmed by mutation analysis, skin histopathologic examination, or both. Sixteen patients were investigated by indocyanine green (ICG) and fluorescein angiography, confocal near-infrared (NIR) reflectance, and fundus autofluorescence imaging using a confocal scanning laser ophthalmoscope (Spectralis HRA-OCT; Heidelberg Engineering, Heidelberg, Germany). Composite digital fundus photography also was performed. Characterization and topographic distribution of abnormalities detected by retinal imaging. On late-phase ICG angiography, a central area of decreased fluorescence centered on the posterior pole was a characteristic finding in all patients. A second area characterized by increased fundus reflectivity on NIR reflectance imaging extended further into the periphery. A third and most eccentric area showed neither decreased ICG fluorescence nor increased fundus reflectivity. These 3 areas were separated by 2 transition zones, the second being the equivalent of peau d'orange. Angioid streaks did not extend into the third area. The abnormalities detected by this multimodal imaging approach suggest a centrifugal spread of the retinal pathologic features of the Bruch's membrane-RPE complex in PXE. Decreased fluorescence on late-phase ICG angiography is a consistent sign of retinal pathologic features in PXE. Bruch's membrane calcification may be the underlying cause for the increased reflectivity observed on NIR reflectance imaging. Proprietary or commercial disclosure may be found after the references.

Indocyanine green angiography-guided laser photocoagulation combined with sub-Tenon's capsule injection of triamcinolone acetonide for idiopathic macular telangiectasia

AimsType 2 (perifoveal) telangiectasia often is refractory to treatment, because focal targets such as aneurysms are not detected by fluorescein angiography (FA) in these eyes. The authors evaluated the efficacy...

Polypoidal choroidal vasculopathy and late geographic hyperfluorescence on indocyanine green angiography

Background/aims:To report the clinical significance of late geographic hyperfluorescence (LGH) on indocyanine green angiography (ICGA) in cases of polypoidal choroidal vasculopathy (PCV).Methods:The medical records of 43 eyes with PCV, all...

LACQUER CRACK FORMATION AND CHOROIDAL NEOVASCULARIZATION IN PATHOLOGIC MYOPIA

To clarify the characteristics of choroidal neovascularization (CNV) due to myopic CNV (mCNV) and the relation to lacquer crack (LC) formation. Thirty-seven eyes with mCNV underwent fluorescein angiography (FA) and indocyanine green angiography (ICGA) using Heidelberg Retina Angiograph 2 (HRA2; Heidelberg, Germany). mCNV was detected by FA and ICGA; LCs were detected by late-phase ICGA. Thirty-five eyes (95%) had classic mCNV, and 2 (5%) had occult CNV. LCs developed in 35 (95%) of 37 eyes. In 33 eyes (94%), classic mCNV originated from LCs; the 2 other eyes had small horizontal dotlike LCs, but mCNV originated from the adjacent area of LC. No occult CNV was associated with LCs. Two morphologic types of LCs were observed, linear (21 eyes [62%]) and stellate (12 eyes [32%]) from which mCNV originated, with no significant differences in parameters between the two types. Classic mCNV demonstrated well-delineated hyperfluorescence by late-phase ICGA in 10 eyes (29%), which was significantly correlated with absence of a dark rim (P = 0.022). ICGA using HRA2 provides more detailed information on mCNV and LCs. LC formation is essential for classic mCNV to develop. Morphologic variations of LCs were not different clinically. Late-phase hyperfluorescence, probably due to the absence of pigment epithelium around the mCNV, may represent its activity.

Effects of photodynamic therapy on the choriocapillaris and retinal pigment epithelium in the irradiated area

To evaluate the effect of photodynamic therapy (PDT) on the choriocapillaris and retinal pigment epithelium (RPE) in the irradiated area surrounding choroidal neovascularization (CNV) during 12 months of follow-up. We reviewed the medical records, and indocyanine green angiography (IA), fluorescein angiography (FA), and fundus photographic findings of 72 eyes (72 patients) with CNV associated with age-related macular degeneration (AMD) or polypoidal choroidal vasculopathy (PCV). Patients were divided into three groups based on the number of PDT sessions. Twelve months after PDT, we evaluated the relationship between the number of sessions and both the presence of hypofluorescence in the late phase of IA and window defects observed on FA in the irradiated areas. Twenty-three patients had one PDT session (group I), 25 had two (group II), and 24 had three or four (group III). IA revealed hypofluorescence indicating a choriocapillaris filling defect within the irradiated area in 11 eyes (48%) in group I, 18 (72%) in group II, and 22 (91%) in group III. The correlation between the number of PDT sessions and hypofluorescence in the irradiated areas was significant. FA showed window defects surrounding CNV in 26%, 52%, and 71% of eyes from groups I, II, and III, respectively. Subretinal hemorrhages had been present in 23 eyes (32%) and exudation in 13 (18%) prior to PDT. Areas without hemorrhages or exudation prior to PDT had a normal appearance within the irradiated area in all 72 eyes. Although the RPE in the irradiated area was preserved, 12 months after PDT, mild choriocapillaris occlusion was detected in the irradiated area in eyes that had undergone multiple PDT sessions.

Autofluorescence and Angiographic Findings of Retinal Astrocytic Hamartomas in Tuberous Sclerosis

Objective: To describe fundus autofluorescence (AF), fluorescein angiography (FA) and indocyanine green angiography (ICGA) in different types of retinal astrocytic hamartomas in tuberous sclerosis (Morbus Bourneville-Pringle). Methods: Two eyes with 8 lesions, i.e. type 1 (n = 7) and type 3 (n = 1), were examined. AF pictures were taken prior to injection, FA and ICGA images were obtained in the early and the late phase. To achieve additional cases, a systematic literature review with exten- sive Internet and library search was performed. Results: Strong AF was seen in type 2 and type 3 retinal astrocytic hamartomas, whereas type 1 lesions blocked the physiologic fundus AF. Fluorescence angiography of all types of lesions revealed hypofluorescence in early frames and hyperfluorescence originating from leakage in late frames. ICGA showed a subtle blockade in type 1, a total blockade in type 2 and in the central part and a partial blockade in the peripheral part in type 3 lesions. Conclusions: Retinal astrocytic hamartomas in tuberous sclerosis can be easily detected by angiography, especially type 1 lesions which are difficult to visualize by funduscopy. Early- and late-phase fluorescein angiography and ICGA are helpful to differentiate the three lesion types.

Sequence of early vascular events after photodynamic therapy.

To identify early vascular changes in choroidal neovascularization (CNV) and in adjacent normal choroid, after photodynamic therapy (PDT). In a prospective study, 40 patients with predominantly classic CNV due to age-related macular degeneration (AMD) were treated with PDT performed with verteporfin. Verteporfin was administered intravenously at a dose of 6 mg/m(2) body surface area. A near infrared laser light dose of 50 J/cm(2), an irradiance of 600 mW/cm(2) and a wavelength of 692 nm was applied. A scanning laser system was used to perform confocal fluorescein angiography (FA) and indocyanine green angiography (ICGA) before treatment and regularly at 5 hours, 1 day, 1 week, and 3 months after PDT. Images were analyzed for CNV size and leakage area as seen by FA and ICGA. Collateral damage within the surrounding choroid was documented based on the hypofluorescence in early- and late-phase ICGA. No immediate occlusion of the CNV complex was found angiographically, but a dynamic change over time was observed in the early perfusion patterns and late-phase hyper- and hypofluorescence. At 5 hours after treatment, large portions of the CNV lesion were still perfused. One day after PDT, CNV size in early FA and early ICGA reached its minimum, at 0.49 mm(2) (15.7%) and 0.78 mm(2) (31.1%) of the initial area, respectively. In late-phase FA and ICGA, however, an immediate massive exudation with a continuous increase in hyperfluorescence originated from the CNV and surrounding choroid, with a maximum in leakage area at 1 day. At 1 week PDT-induced exudation slowly resolved. Eyes in 36 patients showed some choroidal hypofluorescence by ICGA before treatment. A progressive increase of the hypofluorescent area surrounding the CNV was observed, which correlated with the size of the laser spot. Maximum hypofluorescence was noted at 1 week with an average size of 11.1 mm(2) in early- and late-phase ICGA. In contrast to findings in experimental animals, PDT in humans with classic CNV did not induce immediate thrombosis, but primarily caused a breakdown of vascular barriers. A characteristic sequence of vascular changes was observed with early, enhanced leakage from the CNV and normal choroid followed by nonperfusion later. Occlusion of the CNV lesions occurred 1 day after treatment, but closure of the adjacent choroidal vessels proceeded slowly over as long as 1 week.

Indocyanine Green Angiograms of Choroidal Nevi: Comparison Between Confocal and Nonconfocal Scanning Laser Ophthalmoscope and Fundus Video Camera

Purpose: A fundus video camera and a nonconfocal scanning laser ophthalmoscope (SLO) detect direct light and indirect light, whereas a confocal SLO detects mostly direct light. Differences in confocal and nonconfocal SLO images and fundus video camera images are most likely due to their different optical systems. These differences were examined in indocyanine green (ICG) angiograms of a choroidal nevus. Methods: A confocal SLO, a nonconfocal SLO, and a high resolution digital fundus video camera were used to obtain ICG angiograms of pigmented choroidal nevi in 4 patients for 30 minutes following dye injection. Results: All the angiograms showed a hypofluorescent region in the nevus until 10–14 minutes after dye injection, except in 1 patient in whom no hypofluorescent region was seen in an early confocal-SLO angiogram. From 20 minutes to 30 minutes postinjection, the hypofluorescent regions were still visible in all fundus video camera angiograms and nonconfocal SLO angiograms but not in confocal SLO angiograms. Conclusions: Early angiograms taken with the three angiography systems showed a similar appearance of the choroidal nevus. However, late ICG angiograms with a confocal SLO showed different images from those taken with a nonconfocal SLO or a fundus video camera. It is suggested that the angiography system and the aperture size of an SLO should be selected according to the aspect of the pigmented choroidal nevus that is of interest in late-phase ICG angiography.

Treatment of Exudative Age-related Macular Degeneration

I. Prophylactic Treatment We followed 75 eyes contralateral to eyes with exudative age-related macular degeneration (AMD), using indocyanine green angiography (IA), for more than one year. Hyperfluorescent areas in the late phase of IA were seen in 19 eyes at the initial examination, and in 25 eyes during follow-up. Exudative AMD developed in 9 of the 25 eyes. Using timetable analysis, we estimated that 11% of these 27 eyes developed AMD within one year and 55% within three years. The hyperfluorescent areas seen on IA appeared to be latent choroidal neovascularization (CNV) under the retinal pigment epithelium. We propose that photocoagulation aimed at hyperfluorescent areas should be considered in such cases. We performed prophylactic laser photocoagulation in 21 eyes, which were then followed up for at least six months. These eyes all had 10 or more serous drusen within 1,500 μm of the fovea and did not show hyperfluorescence, suggesting latent CNV in the late phase of IA. The majority or a small fraction of the serous drusen disappeared in 48% and 18% of the 21 eyes, respectively. CNV appeared adjacent to the laser scar in one eye (5%). Judging from these results, it is important to establish a method of definitively abolishing drusen and preventing the development of CNV. II. Treatment of CNV Of 229 eyes which showed occult CNV in fluorescein angiography (FA), 124 eyes (54%) showed classic CNV outside the fovea on IA. One hundred and two of the 124 eyes (45%) underwent laser photocoagulation. We evaluated indocyanine green guided laser photocoagulation of extrafoveal CNV in 139 eyes. The success rate was 81% at 3 months after laser photocoagulation. This was estimated using timetable analyses to have decreased to 78% at one year and 71% at three years. Eighty percent of successfully treated eyes showed maintained or improved visual acuity. These results did not differ significantly from those obtained with laser photocoagulation based on FA findings. When classic CNV is not detected on FA, IA is indicated and if classic CNV is detected outside the fovea, photocoagulation should be performed aggressively. We compared the histological findings of removed subfoveal CNV with the IA findings prior to removal. IA findings of CNV before removal were divided into four types. Types I and II showed numerous vascular lumina in von Willebrand factor staining. Prominent proliferation in types I and II was demonstrated with Ki-67. Vascular endothelial growth factor (VEGF) showed strong staining in types I, II and III. Therefore, CNV in eyes with types I, II and III, and especially type I, requires urgent treatment. We compared visual outcomes one year after treatment between 52 eyes that underwent removal and 56 eyes that underwent laser photocoagulation of subfoveal CNV. When CNV size was one disc diameter or less, mean visual acuity, the percentage of eyes with improved vision and with a visual acuity of 0.1 or more, was significantly greater in operated eyes than in coagulated eyes. Removal is therefore superior to photocoagulation in subfoveal CNV of one disc diameter or less in size. We evaluated preoperative factors influencing the best corrected visual acuity at least six months after removal of subfoveal CNV in 67 eyes. Factors influencing the best corrected visual acuity were IA findings, feeder vessel ingrowth sites and CNV sizes. Good indications for removal included types I, II and III IA findings, extra foveal location feeder vessel ingrowth sites, and small CNV. III. Low Vision Care We performed reading tests using the MN read J chart for 90 eyes with the scar stage of CNV. Reading speed profiles of the 90 eyes were classified into two groups: 48 eyes showing a plateau with a relatively constant reading rate at the maximum level; and 42 eyes showing steadily increasing reading rate without a plateau. Eyes without a plateau had worse visual acuity, worse reading acuity, and slower reading speed. We evaluated newspaper reading performance by comparing conventional versus new methods based on the critical print size of the MN read J chart. Magnification power based on the critical print size were similar to those finally chosen as the best aid by the patients. On the other hand, magnification power was lower when conventional methods were used. The critical print size of the MN Read J chart appears to be valuable for determining low vision aids which facilitate reading by AMD patients.

Hyperfluorescent Areas Observed in Late-phase Indocyanine Green Angiography (IA) of IA Findings in Fellow Eyes of Unilateral Age-related Macular Degeneration

Purpose: To evaluate abnormal findings of indocyanine green angiography (IA), predisposing to exudative age-related macular degeneration (AMD) in fellow eyes of unilateral exudative AMD. Methods: We categorized 83 fellow eyes of unilateral exudative AMD into two groups, ie, 55 eyes with early age-related maculopathy, and 28 eyes with normal aging. We performed IA. Results: The late phase of IA demonstrated hyperfluorescent areas in 27 of the 83 fellow eyes, which included 22 of the 55 eyes with early age-related maculopathy and five eyes of 28 eyes with normal aging. The prevalence of the late-phase hyperfluorescence was statistically significant in early age-related maculopathy. Eight of the 22 eyes with early age-related maculopathy and one of the five eyes with normal aging progressed to exudative AMD. Conclusions: Hyperfluorescent areas observed in late-phase IA before the manifestation of exudative AMD suggested the possible presence of choroidal neovascular membrane in the subretinal pigment epithelial space.

Case Report: Indocyanine Green Dye Leakage from Retinal Artery in Branch Retinal Vein Occlusion

Little is known about retinal vascular lesions underlying hemorrhage in the acute phase of branch retinal vein occlusion (BRVO). A 64-year-old woman presented with a decrease in visual acuity of ten-day duration in her left eye. At the initial examination, her left fundus showed the typical appearance of BRVO, including retinal bleeding and soft exudates in the lower half of the fundus, after the arteriovenous crossing. Fluorescein angiography showed no detail in the retinal vessels, which were occluded by retinal bleeding. However, in the early phase of indocyanine green (ICG) angiography, ICG dye leaked from the retinal artery at a point proximal to the first bifurcation. In the late phase of ICG angiography, the dye pooled along the retinal artery in a fusiform fashion. One year after laser photocoagulation was performed in the area of the BRVO, ICG dye leakage from the retinal artery had completely disappeared. These findings suggest that the changes in the retina detected by ICG angiography may have been associated with the onset of BRVO. In patients with acute BRVO, ICG angiography may be used to evaluate retinal arterial lesions covered by hemorrhage and provide useful information.

Knobby-like Choroidal Neovascularization Accompanied With Retinal Pigment Epithelial Detachment

Purpose: To evaluate the clinical features of knobby choroidal neovascularization (CNV) which was detected using indocyanine green (ICG) angiography and the association between knobby CNV and idiopathic polypoidal choroidal vasculopathy (IPCV). Method: We studied 164 eyes with retinal pigment epithelial detachment (PED) accompanied with CNV. These patients were older than 50 years. We detected knobby CNV in 96 eyes of 164 PED eyes (58.5%). Knobby CNV was defined as follows: knobbed blood vessels were observed from the early phase and remained hyperfluorescent through the ICG angiography. We classified 3 groups on the basis of the types of vessels with knobby CNV: group I, multiple isolated knobby CNVs without continuous vessels (24 eyes); group II, knobby dilatations in some parts of CNV (45 eyes); group III, network vessels ending in multiple aneurysmal swelling as in IPCV (27 eyes). Result: We found knobby CNV is only 20% of eyes with serous PED, but about 70% in neovascular, serosanguineous, and hemorrhagic PED. The ratio of each group showed no distinction statistically. Knobby CNV mostly appeared in macular areas, and was frequently accompanied with subretinal or subpigment epithelial hemorrhage. Subretinal reddish-orange lesions were seen in 50% of group I, 60% of group II, and 89% of group III. Knobby CNV showed occult CNV in fluorescein angiography. In late phase ICG angiography, knobby CNV leaked ICG. New lesions occurred in all groups. Conclusion: We think that knobby CNV is a common finding in subpigment epithelial neovascularization, and that IPCV vascular lesion is one type of subpigment epithelial neovascularization.

Indocyanine Green Angiography of Drusen

To analyze the indocyanine green angiographic findings of drusen in the early stages of age-related macular degeneration. Sixty-nine eyes of 53 consecutive patients with drusen but without exudative complications of age-related macular degeneration were studied. Drusen were classified into four groups: hard drusen, drusen derived from clusters of hard drusen (hard cluster-derived drusen and soft cluster-derived drusen), membranous drusen, and regressing drusen. An additional category was constituted by reticular pseudodrusen that could be associated with drusen of either the inner or outer macula. Results of contact lens biomicroscopy and fluorescein angiography were compared with findings on indocyanine green angiography. Hard drusen, either isolated hard drusen or hard cluster-derived drusen, were hyperfluorescent during indocyanine green angiography; in contrast, all sizes of soft drusen derived from clusters of hard drusen were hypofluorescent throughout the angiogram. Membranous drusen, visible on biomicroscopy and fluorescein angiography, were not visible during indocyanine green angiography. Regressing drusen may have showed hyperfluorescence at the early stages of indocyanine green angiography, but associated calcium and pigmentation were hypofluorescent. Reticular pseudodrusen were visible on red-free photographs; on midphase and late-phase indocyanine green angiography using the scanning laser ophthalmoscope only, reticular pseudodrusen were seen as a pattern of hypofluorescent dots. The indocyanine green angiographic findings add to and support the clinicopathologic classification of drusen. Indocyanine green angiography may help to distinguish the different types of drusen and may thus be of use in evaluating the risk of progressive age-related macular degeneration in patients with drusen.

Observations of different presentations of choroid neovascularization in indocyanine green angiography

The interpretation of choroidal neovascular membranes (CNV) in indocyanine green angiography (ICG-A) is difficult. It is not known whether demarcated hyperfluorescence in the ICG-A reliably reflects the true morphology and the total extent of a CNV. Therefore, in this retrospective study, the patterns of fluorescein and ICG angiograms were evaluated and compared in both occult and well-defined CNV. In 153 out of a total of 168 cases with CNV, age-related macular degeneration (AMD) was the underlying disease. CNV was occult in 114 and well-defined in 39 cases. The angiographic examinations with both dyes were performed with a modified fundus camera combined with a digital imaging system. In the group of AMD patients with occult or ill-defined CNV. 42 cases (36.8%) showed a defined membrane in the ICG stain. The filling patterns of ICG were extremely variable. In the group of AMD patients with classic CNV, ICG-A showed evidence of staining in the early and late phase in 14/39 cases (36%), exclusively in the early phase in 5/39 (13%) cases and only in the late phase in 17/39 cases (44%). Surprisingly, three well-defined membranes in fluorescein angiography (FLA) were not seen in any phase of the ICG-A. Compared with FLA, the 17 CNVs with demarcation only in the late phase of the ICG-A were seen to be larger in 8 and smaller in 9 cases while all CNVs seen in the early phase, or in both early and late phase, were of identical size with the early fluorescein staining. The pattern of ICG staining of CNV is complex. The single finding of a demarcated hyperfluorescence in the late phase of ICG-A should be interpreted with utmost caution, particularly in regard to planning laser therapy.

Indocyanine green angiography in choriocapillary atrophy induced by sodium iodate

•Background: The interpretation of indocyanine green (ICG) angiograms is uncertain in many aspects. We performed a study to examine the involvement of the choriocapillaris (CC) in the late phase of ICG angiography. •Methods: An animal model of chorioretinal atrophy prepared by means of injection of sodium iodate 4 months previously was used. The findings of ICG angiography and histological analysis were compared. • Results: In the late phase of ICG angiography, three fluorescence patterns were observed: the normal region with diffuse ICG fluorescence, a hypofluorescent region with no diffuse fluorescence, and a region with a mixture of hypofluorescence and bright fluorescence. Histological analysis revealed that there were normal CC endothelial cells bearing fenestrae in the region of normal fluorescence. In the region of hypofluorescence, the CC was almost completely obstructed and remnants of capillaries contained thick cytoplasm and lacked fenestrae. In the mixed region of hypofluorescence and bright fluorescence, the CC was partially obstructed and thickened endothelial cells formed intercellular junction complexes by overlapping each other in a complicated manner. Amorphous substances were deposited in some parts of the choroidal interstitium. • Conclusion: The CC may play some role in generating diffuse fluorescence in the late phase of ICG angiography, and the findings of hypofluorescence and bright fluorescence may be related to CC obstruction and increased permeability of abnormal vessels, respectively.