Clinical application of digital indocyanine green videoangiography in senile macular degeneration

Distribution and Location of Vortex Vein Ampullae in Healthy Human Eyes as Assessed by Ultra-Widefield Indocyanine Green Angiography

PURPOSE

To study the number and distribution of vortex ampullae in healthy eyes using ultra-wide field (UWF) indocyanine green angiography (ICGA).

DESIGN

Prospective, observational study.

PARTICIPANTS

Thirty-six eyes of 36 healthy participants with no evidence of ocular or systemic disease.

METHODS

The UWF ICGA images (central and peripheral steered) were captured using the Optos California (Optos, Dunfermline, United Kingdom) instrument. The images were projected stereographically to correct for peripheral distortion and obtain accurate measurements. All images were graded and analyzed for number, location, and distance of the vortex vein ampullae from the center of optic nerve.

MAIN OUTCOME MEASURES

Mean number and the distance of ampullae from the center of optic nerve in all quadrants.

RESULTS

The mean number of ampullae observed by UWF ICGA was 8.0±2.1 (range, 5-13). The mean distance of a vortex vein ampulla from the optic nerve was 14.2±1.1 mm (range, 10.3-17.7 mm). The frequency of ampullae was higher in the superior and inferior quadrants than the nasal and temporal quadrants. Ampullae were never observed in the 3- or 9-o'clock meridians. Multiple regression analysis showed no relationship with age, gender, axial length, or ethnicity. Excellent intergrader reproducibility was found between graders with an intraclass correlation coefficient (distance measurements: intraclass correlation coefficient, 0.99; 95% CI, 0.979-0.999; P < 0.001; number of ampullae: intraclass correlation coefficient, 0.99; 95% CI, 0.988-0.999; P < 0.001).

CONCLUSIONS

The number of discrete vortex vein ampullae that can be discerned by UWF ICGA in healthy individuals is greater frequently and substantially than the 4 that are traditionally thought to drain the major quadrants. Considerable variability in the number and position of the ampullae may be apparent in healthy individuals.

Choroidal vasculature imaging with laser Doppler holography

The choroid is a highly vascularized tissue supplying the retinal pigment epithelium and photoreceptors. Its implication in retinal diseases is gaining increasing interest. However, investigating the anatomy and flow of the choroid remains challenging. Here we show that laser Doppler holography provides high-contrast imaging of choroidal vessels in humans, with a spatial resolution comparable to state-of-the-art indocyanine green angiography and optical coherence tomography. Additionally, laser Doppler holography contributes to sort out choroidal arteries and veins by using a power Doppler spectral analysis. We thus demonstrate the potential of laser Doppler holography to improve our understanding of the anatomy and flow of the choroidal vascular network.

Incidence of Fellow Eye Involvement in Patients With Unilateral Exudative Age-Related Macular Degeneration

Importance

Since the advent of optical coherence tomography angiography (OCT-A), nonexudative neovascularization has been described in the fellow eyes of unilateral exudative age-related macular degeneration (AMD). However, there is limited literature describing the natural course and optimal management of these lesions.

Objective

To determine the incidence of fellow eye involvement in patients presenting with unilateral typical AMD or polypoidal choroidal vasculopathy and to evaluate the patterns of OCT-A changes within 6 months before the onset of exudative changes, especially focusing on nonexudative neovascularization.

Design, Setting, and Participants

Data for this study were taken from a prospective, observational cohort study involving Asian patients with exudative AMD in the Asian AMD Phenotyping Study between October 2015 and March 2016. Analyses began in June 2017. Only patients who had gradable OCT-A and indocyanine green angiography (ICGA) scans of the fellow eye at baseline and follow-up at least 6 months apart were included for the analysis. The contralateral eye was evaluated for presence of nonexudative neovascularization based on multimodal imaging, which included ICGA, spectral domain optical coherence tomography, and OCT-A.

Main Outcomes and Measures

The difference between the incidence of those with nonexudative choroidal neovascularization and those without as analyzed using log-rank test and qualitative analysis of OCT-A images.

Results

We included 95 fellow eyes of 95 patients who presented with unilateral exudative AMD with a mean (SD) age of 68.6 (8.6) years. Nonexudative neovascularization was present in 18 eyes (19%) (8 [22.9%] and 10 [19.0%] fellow eyes with typical AMD and polypoidal choroidal vasculopathy, respectively; 8 [44.4%] on OCT-A; 5 [27.8%] on ICGA; and 5 [27.8%] on both OCT-A and ICGA). Development of exudative changes was noted in 6 fellow eyes (6.3%). Four eyes developed exudation from previously noted nonexudative neovascularization, and 2 eyes arose exudative changes from de novo. The probability of developing exudation within 6 months was significantly higher in eyes with baseline nonexudative neovascularization (0.087; 95% CI, 0.0033-0.210) compared with eyes without (0.010; 95% CI, 0.0026-0.041) (P = .008). In all eyes whose OCT-A images were available immediately before the onset of exudative changes, there was an increase in the size of network vessels compared with baseline.

Conclusions and Relevance

The presence of nonexudative neovascularization may predispose to the development of exudative changes.

CLINICAL ENDPOINTS FOR THE STUDY OF GEOGRAPHIC ATROPHY SECONDARY TO AGE-RELATED MACULAR DEGENERATION

PURPOSE

To summarize the recent literature describing the application of modern technologies in the study of patients with geographic atrophy (GA) secondary to age-related macular degeneration.

METHODS

Review of the literature describing the terms and definitions used to describe GA, imaging modalities used to capture and measure GA, and the tests of visual function and functional deficits that occur in patients with GA.

RESULTS

In this paper, we describe the evolution of the definitions used to describe GA. We compare imaging modalities used in the characterization of GA, report on the sensitivity and specificity of the techniques where data exist, and describe the correlations between these various modes of capturing the presence of GA. We review the functional tests that have been used in patients with GA, and critically examine their ability to detect and quantify visual deficits.

CONCLUSION

Ophthalmologists and retina specialists now have a wide range of assessments available for the functional and anatomic characterization of GA in patients with age-related macular degeneration. To date, studies have been limited by their unimodal approach, and we recommend that future studies of GA use multimodal imaging. We also suggest strategies for the optimal functional testing of patients with GA.

Age-dependent variations in the drusen fluorescence on indocyanine green angiography

PURPOSE

To examine the fluorescence patterns of macular drusen using indocyanine green (ICG) angiography in human subjects of different ages.

METHODS

A total of 180 eyes in 100 consecutive patients aged 34-90 years with macula drusen were evaluated with ICG angiography using the Topcon 1024 ImageNet system. Eyes were divided into two groups depending on age. The older group (subjects over the age of 55 years) comprised 170 eyes. The younger group (subjects 55 years or younger) comprised 10 eyes. The fluorescence patterns of the drusen were graded as hyper-fluorescent (brighter than the background fluorescence), hypofluorescent (darker than the background fluorescence) or isofluorescent (unable to be distinguished from the background fluorescence). The ICG angiogram appearances were correlated with the clinical types of drusen in differing age groups.

RESULTS

An age-dependent difference in the fluorescence pattern of drusen was observed. Drusen in the older group were hypofluorescent or isofluorescent (169/170 eyes). In contrast, drusen in the younger group (55 years or younger) were hyperfluorescent (10/10 eyes).

CONCLUSIONS

This study defines the distinct age-dependent differences in the ICG fluorescence pattern of drusen. This heterogeneity might be due to differential binding of extravasated ICG to the constituents and histological site of the drusen deposits. Furthermore, ICG angiography is able to differentiate drusen types not possible by clinical and fluorescein angiographic evaluation.

Eligibility for treatment and angiographic features at the early stage of exudative age related macular degeneration

AIMS

To determine the eligibility for laser photocoagulation treatment or for photodynamic therapy (PDT) with verteporfin in eyes at the earliest stage (first month of symptoms) of exudative age related macular degeneration (AMD) based on fluorescein angiographic (FA) features; to evaluate the potential contribution of indocyanine green angiography (ICG-A) for occult choroidal neovascularisation (CNV) at this stage.

METHODS

Retrospective review of 252 consecutive patients (269 eyes) examined within the first month of symptoms of exudative AMD.

RESULTS

On FA, 97 eyes (36%) had classic CNV alone. Occult CNV associated with fibrovascular retinal pigment epithelium detachments (PEDs) was observed in 71 eyes (26%) and without fibrovascular PED in 101 eyes (38%). 91 eyes (34%) met the Macular Photocoagulation Study criteria for laser photocoagulation. 53 eyes (20%) met the Verteporfin In PDT (VIP) or Treatment of AMD with PDT (TAP) studies criteria. By ICG-A, occult CNV was visualised as focal spots in 49% of eyes examined within 15 days v 32% of eyes examined between 16 and 30 days after the onset of symptoms (p=0.07). 8.5% of late staining plaques disclosed in eyes examined within 15 days were combined with focal spots v 36% in eyes examined between 16 and 30 days (p<0.01).

CONCLUSIONS

Early examination of eyes with exudative AMD would allow the treatment of 47% of eyes. 60% of eyes with subfoveal CNV would be eligible for PDT with verteporfin. Up to half of eyes with occult CNV would be converted by ICG-A into well delineated focal spots.

Fluorescence properties and metabolic features of indocyanine green (ICG) as related to angiography

Indocyanine green (ICG) is a fluorescent dye that has been used for the imaging of retinal and choroidal vasculatures for more than 30 years. Its high molecular weight, specific metabolic features, and its infrared spectra make the specificity of the images obtained with this dye in ophthalmology. The focus of this paper is to review the basic properties of ICG and to show how some clinical features related to basic properties also depend on the instrumentation used to perform ICG angiography. Indocyanine green has a complex molecular structure that leads to amphiphilic properties, that is, both hydrophilic and lipophilic properties. These properties explain that a specific interaction with phospholipids influences the emission spectrum and the fluorescence yield of ICG. The composition of cell membranes mainly composed of phospholipid bilayers is consistent with a binding and/or a diffusion of ICG molecules observed on angiograms. Likewise, ICG can bind to the lipid component of miliary drusen, explaining their hyperfluorescence. A knowledge of ICG basic properties and interactions may allow a better understanding of angiograms performed with this dye.

Indocyanine-green videoangiography of drusen as a possible predictive indicator of exudative maculopathy

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.

Indocyanine green angiography of drusen

PURPOSE

To analyze the indocyanine green angiographic findings of drusen in the early stages of age-related macular degeneration.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Indocyanine green hyperfluorescence associated with serous retinal pigment epithelial detachment in age-related macular degeneration

PURPOSE

Indocyanine green (ICG) angiography may improve visualization of choroidal neovascularization (CNV) associated with serous retinal pigment epithelial detachment (RPED) in age-related macular degeneration (AMD). The features of ICG hyperfluorescence associated with serous RPED and therapeutic effect of ICG-directed laser photocoagulation in eyes with serous RPED is evaluated.

DESIGN

Retrospective review of all simultaneous fluorescein/ICG angiograms (n = 918) performed over an 18-month period to identify 44 eyes in 39 patients with serous RPED secondary to AMD on fluorescein angiography.

PARTICIPANTS

Thirty-nine patients with AMD, aged 53 to 89 years, participated.

INTERVENTION

Eyes were nonrandomly treated with ICG-directed laser photocoagulation or observation.

MAIN OUTCOME MEASURES

Characteristics of ICG hyperfluorescence associated with a serous RPED are reviewed. Final visual acuity and anatomic appearance of the serous RPED are given.

RESULTS

Twenty-three (52%) of the 44 eyes had an isolated serous RPED without obvious CNV, and 21 (48%) of the 44 eyes had a serous RPED associated with occult CNV on fluorescein angiography. Indocyanine green angiography demonstrated underlying CNV in 19 eyes (83%) with an isolated serous RPED and in all 21 eyes (100%) with serous RPED and occult CNV. The pattern of ICG hyperfluorescence revealed focal CNV in 15 eyes and plaque CNV in 4 eyes with an isolated serous RPED. In eyes with serous RPED and occult CNV, focal CNV and plaque CNV were noted with ICG in 8 and 13 eyes, respectively. No follow-up was available for two eyes. Twenty eyes were treated with ICG-directed laser photocoagulation. In these eyes, the visual acuity remained stable in 6 eyes (30%) and decreased in 14 eyes (70%). Twenty-two eyes were observed, and the visual acuity remained stable in 8 (36%), improved in 2 (9%), and decreased in 12 eyes (55%).

CONCLUSIONS

Although ICG angiography may enhance visualization of CNV associated with serous RPED in AMD, ICG-directed laser treatment did not appear to improve visual acuity when compared with observed eyes in this series.

Classification of choroidal neovascularization by digital indocyanine green videoangiography

PURPOSE

The majority of patients with exudative maculopathy due to age-related macular degeneration present with poorly defined or occult choroidal neovascularization (CNV) that cannot be imaged adequately by fluorescein angiography. Digital indocyanine green (ICG) videoangiography is a new technique that allows enhanced imaging of these poorly defined or occult vessels. The authors studied 1000 consecutive cases of occult CNV using digital ICG angiography to describe the various types of neovascularization observed by this technique and to determine the frequency and natural history of the various lesions.

MATERIALS AND METHODS

Digital ICG videoangiography was performed as described previously on 1000 consecutive eyes with occult CNV by fluorescein angiography.

RESULTS

One thousand consecutive eyes with occult CNV by fluorescein angiography were imaged using digital ICG videoangiography. Three morphologic types of CNV were noted by ICG videoangiography, which included focal spots, plaques (well-defined or poorly defined), and combination lesions (in which both focal spots and plaques are noted). Combination lesions can be subdivided into marginal spots (focal spots at the edge of plaques of neovascularization), overlying spots (hot spots overlying plaques of neovascularization), or remote spots (a focal spot remote from a plaque of neovascularization). The relative frequency of these lesions was as follows: there were 283 cases (29%) of focal spots; 597 cases (61%) of plaques, consisting of 265 cases (27%) of well-defined plaques and 332 cases (34%) of poorly defined plaques; and 84 cases (8%) of combination lesions, consisting of 35 cases (3%) of marginal spots, 37 cases (4%) of overlying spots, and 12 cases (1%) of remote spots. In seven additional cases (1%), a mixture of the above lesions was noted. In 13 additional eyes (1%), no lesions were noted on the ICG angiogram. The studies of 16 eyes were unreadable or unobtainable.

CONCLUSIONS

There are three types of CNV that can be observed by digital ICG videoangiography. Plaques are the most common type and have a poor natural history. Focal spots or hot spots are the next most frequently seen lesion and can potentially be treated by ICG-guided laser photocoagulation. Combination lesions, in which both focal spots and plaques are present, are rare. This study of 1000 consecutive cases of eyes with occult neovascularization that were imaged with digital ICG videoangiography serves to classify the various types of neovascularization observed by this technique. Digital ICG videoangiography is an important tool in better delineating eyes with occult CNV. Future studies are necessary to validate our findings.

Indocyanine green angiographic findings in central serous chorioretinopathy

There has been great controversy about the pathogenesis of the focal changes in the retinal pigment epithelium (RPE) causing detachment of the neurosensory retina in central serous chorioretinopathy (CSC). This study was performed to evaluate changes in choroidal perfusion in 15 patients with CSC. Fluorescein and indocyanine green (ICG) angiography was performed in patients with acute or chronic recurrent CSC. In all patients delayed arterial filling followed by capillary and/or venous congestion, in some cases adjacent to ischemic areas, was found in the choroid. Leakage from the RPE in fluorescein angiography was only observed in those areas with choroidal capillary and/or venous congestion. The preliminary results suggest that venous congestion possibly in association with ischemia causes hyperpermeability of choroidal vessels already described in the literature.

Digital indocyanine-green videoangiography of occult choroidal neovascularization

BACKGROUND

Occult choroidal neovascularization (CNV) secondary to age-related macular degeneration occurs in the majority of patients with exudative maculopathy. Since occult CNV cannot be imaged clearly by fluorescein angiography, this condition is untreatable. The authors performed digital indocyanine-green videoangiography (ICG-V) on 657 consecutive eyes with occult CNV by fluorescein angiography to determine if this technique could be useful in enhancing the imaging of the neovascularization, and thus increasing treatment eligibility.

MATERIALS AND METHODS

Six hundred fifty-seven consecutive eyes with occult CNV were studied. The fluorescein and ICG angiograms were compared, and the percentage of patients potentially eligible for laser therapy based on ICG findings was calculated.

RESULTS

Of 413 eyes with occult CNV without pigment epithelial detachments, focal areas of neovascularization were noted in 89 (22%). Overall, 142 (34.3%) eyes had lesions that were potentially treatable by laser photocoagulation based on additional information provided by ICG-V. Of the 235 eyes with occult CNV and vascularized pigment epithelial detachments, 98 (42%) were eligible for laser therapy based on ICG-V findings. The authors calculate that ICG-V enhances the treatment eligibility by approximately one third.

CONCLUSIONS

In diagnosing occult CNV, ICG-V is an important adjunctive technique to fluorescein angiography. This technique is especially useful in delineating occult neovascularization, neovascularization with overlying subretinal hemorrhage or serosanguineous fluid, and neovascularization associated with pigment epithelial detachments. The authors currently suggest that ICG-V be performed in eyes in which well-delineated neovascularization cannot be identified by fluorescein angiography. Based on their preliminary study, it can be expected that one in three patients with occult CNV potentially will be eligible for laser photocoagulation based on ICG-V. Further studies are necessary to confirm these findings.