|Year : 2017 | Volume
| Issue : 2 | Page : 66-70
Correlation of fundus autofluorescence patterns in early dry age-related macular degeneration with optical coherence tomography findings
Ashraf S Shaarawy, Amr S Bessa, Mohamed A Lolah, Ahmed Mahmoud Ragab
Department of Ophthalmology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
|Date of Web Publication||17-Nov-2017|
Ahmed Mahmoud Ragab
309 Malak Hefney Street, Alexandria
Source of Support: None, Conflict of Interest: None
Background: Correlation of abnormal fundus autofluorescence (FAF) patterns with optical coherence tomography (OCT) findings. Aims: The aim of this study was to evaluate FAF patterns in eyes with early dry age-related macular degeneration (AMD) and correlate these patterns with OCT findings. Settings and Design: This was an institutional, observational, cross-sectional study. Subjects and Methods: One hundred and fifty-six eyes of 102 patients with early dry AMD were recruited, FAF imaging was done for all patients with the aid of confocal scanning laser ophthalmoscopy. In addition, OCT imaging was done for all patients. Statistical Analysis Used: Chi-square test was used for analysis. Results: Six FAF patterns have been identified (normal, minimal change, focal increased, linear, patchy, and reticular pattern). There was a statistically significant difference in OCT findings (drusenoid retinal pigment epithelial detachment and inner- and outer-segment junction integrity) among various FAF patterns. Conclusions: The OCT findings were statistically significant variable among different FAF patterns in eyes with early AMD suggesting a possible link between each FAF pattern and the changes which take place in retinal structure. This finding can aid in determining the visual prognosis of eyes with early AMD according to FAF pattern in large sample studies.
Keywords: Autofluorescence patterns in dry age-related macular degeneration, dry age-related macular degeneration, fundus autofluorescence, optical coherence tomography in dry age-related macular degeneration
|How to cite this article:|
Shaarawy AS, Bessa AS, Lolah MA, Ragab AM. Correlation of fundus autofluorescence patterns in early dry age-related macular degeneration with optical coherence tomography findings. Egypt Retina J 2017;4:66-70
|How to cite this URL:|
Shaarawy AS, Bessa AS, Lolah MA, Ragab AM. Correlation of fundus autofluorescence patterns in early dry age-related macular degeneration with optical coherence tomography findings. Egypt Retina J [serial online] 2017 [cited 2020 Apr 5];4:66-70. Available from: http://www.egyptretinaj.com/text.asp?2017/4/2/66/218591
| Introduction|| |
Lipofuscin accumulation is the hall mark of age-related macular degeneration (AMD). With age lipofuscin accumulates progressively in retinal pigment epithelium (RPE) and subretinal space.,
Lipofuscin has an autofluorescence property, which can lead to abnormal patterns of fundus autofluorescence (FAF). Lipofuscin accumulation can be seen as hyperreflective drusen on optical coherence tomography (OCT) with characteristic retinal changes in the form of drusenoid RPE detachment and inner- and outer-segment (IS/OS) junction disruption.
The aim of this study is to identify the changes on OCT that can company different abnormal FAF patterns among early AMD patients.
| Subjects and Methods|| |
The study was conducted at Alexandria main university hospital between January 2015 and December 2015, Alexandria, Egypt. The study adhered to the tenets of the Declaration of Helsinki. Institutional Review Board/Ethics Committee approval for human studies has been obtained.
Patients with early dry AMD were eligible for enrolment. Inclusion criteria were patients above age of 55 years with clinically documented dry AMD. Exclusion criteria were patients with choroidal neovascular membrane from any cause, patients with any retinal pathology other than dry AMD, patients with previous retinal treatment, myopic patients more than −6 D, also patients with visually significant cataract or media opacity that can affect imaging quality. Patients who had other ocular pathologies, such as uveitis, previous trauma, previous ocular intervention, glaucoma, current use of oral or topical anti-inflammatory agents (steroidal or nonsteroidal), history of steroid responsiveness, were also excluded from the study.
One hundred and fifty-six eyes of 102 patients with early AMD were enrolled in this observational cross-sectional study. All patients were informed about the design of the study and the procedure involved, and all gave written informed consent. A complete patient's evaluation was performed, which included the patient's age, medical, and ocular history. A detailed preoperative ophthalmic evaluation including slit-lamp examination, intraocular pressure measurement with Goldman applanation tonometry, and dilated fundus examination was performed. In addition, best-corrected visual acuity (BCVA) using Snellen acuity chart was examined then converted to logMAR BCVA for statistical analysis. Color fundus photography (Topcon Retinal Camera, TRC50X, Japan) was done for all patients.
FAF images were obtained with (confocal scanning laser ophthalmoscopy) (Heidelberg Retina Angiograph, HRA classic, Heidelberg Engineering, Germany). For excitation, 488 nm argon blue laser was used and emission is recorded above 500 nm with a barrier filter. For acquisition of FAF images, the best 100 single images were aligned, and a mean image was generated. Images of FAF of early AMD eyes were assessed and classified according to classification of FAF patterns in early AMD study.
All patient underwent spectral domain-OCT (Spectralis OCT; Heidelberg Engineering, Germany) scanning. Two main changes on OCT were evaluated in the current study, presence and the location of drusenoid RPE detachment as well as presence of IS/OS junction and its position in relation to the fovea.
Statistical analysis was performed using SPSS software (Statistical Package for the Social Sciences, version 9.0, SPSS Inc., Chicago, III, USA). The difference in OCT changes among different patterns were compared using Chi-square test. A P ≤ 0.05 was considered statistically significant.
| Results|| |
In all 102 patients, 156 eyes had early dry AMD, 77 females and 25 males with mean age 63.35 ± 4.8 years. Six patterns of FAF have been identified in this study; normal, minimal change, focal increased, patchy, and reticular pattern. [Table 1], however, speckled pattern and lacelike pattern which had been described in Bindewald et al. study could not be identified in this study.
|Table 1: Distribution of the studied cases according to fundus autofluorescence phenotypes in early dry age-related macular degeneration|
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The difference in distribution of OCT changes among different patterns was statistically significant (P ≤ 0.05). Interestingly, all eyes with reticular pattern and half the number of eyes with normal pattern showed no drusenoid RPE detachment, while all other patterns showed RPE detachment. Foveal drusenoid RPE detachment was present in all eyes with linear or patchy pattern [Table 2].
|Table 2: Relation between optical coherence tomography drusenoid detachment and early fundus autofluorescence patterns|
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Regarding IS/OS junction disruption, more than one-third of eyes with the normal pattern showed intact IS/OS junction. Conversely, all eyes with other patterns showed the disruption. Foveal IS/OS junction disruption was variable among the patterns with this abnormality, however eyes with reticular, patchy, and linear patterns all had foveal IS/OS junction disruption [Table 3] and [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6].
|Table 3: Relation between optical coherence tomography inner segment/outer segment junction disruption and early fundus autofluorescence patterns|
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|Figure 1: Normal pattern. (a) Left color fundus picture showing multiple hard drusen deposition, right: Fundus autofluorescence of patient showing no fundus autofluorescence abnormality. (b) Optical coherence tomography image of the same patient revealing just retinal pigment epithelium line irregularity with no retinal pigment epithelium detachment and an intact inner- and outer-segment junction.|
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|Figure 2: Minimal change pattern. (a) Left color fundus picture showing hard drusen at the macular area, right: Fundus autofluorescence of the same patient demonstrating abnormal fundus autofluorescence. (b) Optical coherence tomography image demonstrating foveal inner- and outer-segment junction disruption.|
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|Figure 3: Focal increased pattern. (a) Left: Color fundus picture showing hard and soft drusen, right: Fundus autofluorescence of the same patient revealing hyperautofluorescence spots all are <200 μm. (b) Optical coherence tomography image revealing foveal retinal pigment epithelium detachment and extrafoveal inner- and outer-segment junction disruption.|
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|Figure 4: Patchy pattern. (a) Left: Color fundus picture showing predominantly soft drusen at the macular area, right: Fundus autofluorescence of the same patient showing multiple areas of hyperautofluorescence larger than 200 μm with ill-defined borders. (b) Optical coherence tomography image demonstrating foveal retinal pigment epithelium detachment and foveal inner- and outer-segment junction disruption.|
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|Figure 5: Linear pattern. (a) Left color fundus picture showing a large number of soft drusen, right: Fundus autofluorescence of the same patient showing vertical linear hyperautofluorescence. (b) Optical coherence tomography image demonstrating foveal retinal pigment epithelium detachment and foveal inner- and outer-segment junction disruption.|
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|Figure 6: Reticular pattern. (a) Left color fundus picture showing multiple hard drusen along the superiotemporal arcade, right: Fundus autofluorescence of the same patient revealing reticular hypoautofluorescence corresponding to the color fundus lesions. (b) Optical coherence tomography image demonstrating fovea inner- and outer-segment junction disruption.|
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| Discussion|| |
Advancement in retinal imaging has led to more understanding of AMD. FAF as well as OCT represents important investigation tools in evaluating eyes with AMD. Abnormal FAF resulting from drusen deposition and lipofuscin accumulation which can be mapped and followed up. Many classification systems for eyes with early AMD have been described. However, these systems were limited to some extent as changes in eyes with early AMD may not be demonstrated by conventional imaging such as color fundus photography or angiographic imaging. To overcome this, Bindewald et al. have described a new classification for early AMD depending on FAF imaging.
OCT has been used as an effective tool in evaluating eyes with AMD to exclude the presence of fluid in AMD eyes. In this study, it was found that there is a difference between each FAF phenotype in early AMD and the structural changes which have been observed on OCT scan. Two main changes on OCT were studied; IS/OS junction integrity and RPE drusenoid detachment. There was statistical significant difference in RPE drusenoid detachment distribution among the different patterns. Furthermore, this difference has been observed in IS/OS junction disruption among the studied eyes. This was demonstrated previously by Querques et al. who found that a reduced retinal sensitivity always correlates with abnormal FAF and a disrupted IS/OS interface.
The current study has many limitations. The study failed to demonstrate speckled and lacelike pattern which were described by Bindewald et al. This may be related to intra- and inter-observer variability in assessing each pattern. Furthermore, some eyes with early AMD may show confusing pattern of FAF that makes naming some forms of abnormal FAF difficult.
| Conclusions|| |
Changes seen on OCT which are associated with early AMD may be correlated to each FAF pattern. These changes may be linked to certain structural abnormalities that are associated with each pattern. Accordingly, this might indicate a difference in each pattern behavior and, hence, its visual prognosis. Follow-up of these eyes may predict patterns with the highest risk of progression and this may help determining novel risk assessment criteria for progression or conversion to wet AMD.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3]