**4. Treatment of DME**

## **4.1 Systemic control**

The control of all systemic risk factors is vital in the treatment of DME. Optimizing control of diabetes, hypertension, and serum lipids should be emphasized. Optimization of care involves visits to the internist. The intervention aims to reduce glycated hemoglobin, elevated blood pressure, and elevated serum lipids to produce measurable effects in macular thickness in as little as six weeks [114].

The Diabetes Control and Complications Trial (DCCT) reported that tight blood glucose control in patients with type 1 diabetes reduced the cumulative incidence of macular edema at 9-year follow-up by 29% and reduced the application of focal laser treatment for DME by half [115, 116].

The United Kingdom Prospective Diabetes Study (UKPDS), a randomized clinical trial of patients with type 2 diabetes, reported that tighter blood glucose control reduced the requirement for laser treatment at ten years by 29%, compared with looser control; 78% of the laser treatments were for DME [50]. This study also demonstrated that a mean systolic blood pressure reduction of 10 mm Hg and a diastolic blood pressure reduction of 5 mm Hg over a median follow-up of 8.4 years led to a 35% reduction in retinal laser treatments 78% were for DME [51].

The Action to Control Cardiovascular Risk in Diabetes (ACCORD) eye study compared the progression of DR in a Simvastatin plus placebo group, Simvastatin plus fenofibrate group. The rate of progression of DR was lower in the fenofibrate group than in the placebo group [117].

High plasma cholesterol may be associated with more severe hard exudates at the macula [118, 119]. It has been reported that oral Atorvastatin reduced lipid migration to the subfoveal region and decreased the severity of hard exudates in type 2 DM patients with dyslipidemia who had CSME [120]. Nephropathy and anemia can contribute significantly to the risk of DR and DME. Weight loss and cessation of smoking are also crucial in preventing DR and DME.


**7. Authors' case reports**

Over the past year, the authors studied 40 patients with macular dystrophies (27 patients with Best's disease and adult-onset vitelliform foveomacular dystrophy, and 13 patients with Stargardt's disease). SS-OCT and SS-OCTA images were acquired using the DRI OCT Triton machine version 10.11 (Topcon Corporation, Tokyo, Japan). Herein, we present representative cases to demonstrate our findings regarding the morphological alteration in retinal microstructure, retinal vascular plexuses, and choriocapillaris in different stages of both diseases.

#### **7.1. SS-OCT and SS-OCTA findings in Stargardt's disease**

Case 1. Early stage of Stargardt's disease. A 26-year-old male presented with defective vision in both eyes of approximately 1-year duration. His best-corrected visual acuity (BCVA) was 20/63 and 20/50 in the right eye (RE) and the left eye (LE), respectively. Fundus examination revealed bilateral numerous yellowish discrete flecks in the macular area at the level of the RPE. The lesions were identical in appearance though more numerous in the RE. SS-OCT examination revealed bilateral foveal thinning, disrupted ELM and IS/OS photoreceptor junction, and thinning of the choriocapillaris with enhanced visualization of the larger choroidal vessels. SS-OCTA revealed bilateral rarefaction of the SCP and the DCP layers. Affection was more pronounced in the DCP layer. The choriocapillaris showed a moth-eaten appearance instead of the normal hyperintense homogeneous texture, due to the presence of multiple black areas that could correspond to areas of flow void or masking effect by the pisciform lesions. The corresponding flow density maps showed a reduced vessel density that corresponded to vascular rarefaction in the SCP, the DCP, and the choriocapillaris (**Figures 1** and **2**).

disease is controversial. One explanation is that the vitelliform material causes centrifugal displacement of blood vessels in the macular area with resultant progressive atrophy due to mechanical compression. Occasionally, the DCP layer shows a central area of hypointense signal caused by vascular rarefaction and a reduced vessel density surrounded by an annulus of hyperintense signal. This peculiar configuration could be due to overcrowding of vessels being displaced by the vitelliform lesion, or due to compensatory dilatation of the para-macular vascular bed secondary to vessel rarefaction in the macula, with consequent increased blood flow. Likewise, the choriocapillaris shows vascular rarefaction with multiple hypointense flow-void areas, which could be explained by vascular impairment due to degenerative changes induced by mechanical compression or due to masking effect by the accumulating

The most dreadful complication of Best's disease is CNV formation, which could develop in some cases secondary to compromised RPE/Bruch's complex [30, 32–34]. The advent of CNV on top of Best's disease could pose a diagnostic challenge due to overlapping fluorescein patterns of the vitelliform material and PEDs in Best's disease and the fibrovascular and neovascular components of CNV. Likewise, SD-OCT could yield inconclusive results, even when deploying the ultrahigh-definition versions, due to similar backscattering light intensity properties between the amorphous vitelliform and the CNV. OCTA helps disentangle this overlap by its ability to separate erythrocytes from the surrounding static tissue, hence displaying flow in a vascular network that is pathognomonic of CVN formation. In addition, OCTA integrates light-scattering reduction technology (reduced sensitivity roll-off) that preserves the integrity of the incident infra-red laser beam, hence allowing deeper penetration, layer segmentation, and delineation of the neovascular network of CNV from the surround-

Over the past year, the authors studied 40 patients with macular dystrophies (27 patients with Best's disease and adult-onset vitelliform foveomacular dystrophy, and 13 patients with Stargardt's disease). SS-OCT and SS-OCTA images were acquired using the DRI OCT Triton machine version 10.11 (Topcon Corporation, Tokyo, Japan). Herein, we present representative cases to demonstrate our findings regarding the morphological alteration in retinal microstructure, retinal vascular plexuses, and choriocapillaris in different stages of both diseases.

Case 1. Early stage of Stargardt's disease. A 26-year-old male presented with defective vision in both eyes of approximately 1-year duration. His best-corrected visual acuity (BCVA) was 20/63 and 20/50 in the right eye (RE) and the left eye (LE), respectively. Fundus examination

**6.3. Choroidal neovascularization secondary to Best's disease: a diagnostic**

vitelliform material [30–35].

8 OCT - Applications in Ophthalmology

ing vitelliform material [20, 27, 36–40].

**7.1. SS-OCT and SS-OCTA findings in Stargardt's disease**

**7. Authors' case reports**

**predicament**

Case 2. Late stage of Stargardt's disease. A 58-year-old female who was a known case of Stargardt's disease presented for follow-up with complaints of defective vision in both eyes of approximately 2-year duration. Her BCVA was 20/400 and 20/200 in the RE and the LE, respectively. Fundus examination of the RE revealed a sharply circumscribed area of geographic atrophy occupying the macula, approximately of 4 disc diameters (DD) in size. On

**Figure 1.** Case 1. Top left, color photograph of the RE of a 26-year-old male in early stage of Stargardt's disease. Note the numerous subretinal pisciform yellowish flecks occupying the macular area. Bottom left, radial scan SS-OCT shows foveal thinning (168 μ), disrupted ELM and IS/OS photoreceptor junction, and thinning of the choriocapillaris with enhanced visualization of the larger choroidal vessels. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers show vascular rarefaction. Affection is more pronounced in the DCP layer. The choriocapillaris shows a moth-eaten appearance instead of the normal homogeneous hyperintense texture, due to the presence of multiple black areas of flow voids. The corresponding flow density maps show a reduced vessel density that corresponds to vascular rarefaction in the SCP, the DCP, and the choriocapillaris.

the choroidoscleral junction. SS-OCTA of the LE reflected the relatively less advance disease compared to the RE, especially in the choriocapillaris layer which showed multiple flow-void

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Case 3. Adult-onset vitelliform foveomacular dystrophy. A 61-year-old female presented with defective vision in the RE of approximately 6-month duration. Her BCVA was 20/100 and 20/400 in the RE and the LE, respectively. Fundus examination of the RE revealed a subfoveal plaque of amorphous yellowish-white material surrounded by numerous satellite lesions varying in size and in shape, and scattered in the anatomic macula region. On the corresponding FFA, the sub-foveal lesion showed blocked hypofluorescence with multiple pinpoint hyperfluorescent spots due to leakage within PED. The satellite lesions seen in the color

**Figure 3.** Case 2. Top left, color photograph and FFA of the RE of a 58-year-old female in late stage of Stargardt's disease. The fundus shows a sharply circumscribed area of geographic atrophy occupying the macula, approximately 4 DD in size. On FFA, the RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels. More peripheral areas of the lesion demonstrated transmission fluorescence. Bottom left, high-definition line scan (12.0 mm) SS-OCT of the same eye shows marked foveal thinning (84 μ), wiping out of the ELM and the IS/OS layer in the sub-foveal area. The RPE layer is extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers show vascular rarefaction and reduced vessel density. These changes are most pronounced in the DCP layer. The choriocapillaris shows complete loss of vessels in the central portion of the lesion with clear view of the larger choroidal vessels. The central region is surrounded by an annulus of hypointense flow-void areas and vessel rarefaction

areas but with less diffuse atrophy than noted in the RE (**Figures 3** and **4**).

**foveomacular dystrophy**

(arrows).

**7.2. SS-OCT and SS-OCTA findings in Best's disease and adult-onset vitelliform**

**Figure 2.** Case 1. Top left, color photograph of the LE of the same patient as in **Figure 1**. The fundus shows identical lesions to those seen in the RE though less numerous. Bottom left, radial scan SS-OCT reveals foveal thinning (144 μ), disrupted ELM and IS/OS photoreceptors junction, and thinning of the choriocapillaris with enhanced visualization of the larger choroidal vessels. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers demonstrate vascular rarefaction. Affection is more pronounced in the DCP layer. The choriocapillaris shows multiple black areas of flow voids. The corresponding flow density maps show a reduced vessel density that corresponds to vascular rarefaction in the SCP, the DCP, and the choriocapillaris.

FFA, the lesion seen in the color photograph demonstrated that the RPE in the center of the lesion has virtually disappeared with unveiling of the underlying large choroidal vessels. More peripheral areas of the lesion demonstrated transmission fluorescence. SS-OCT of the same eye showed foveal thinning, wiping-out of the ELM, and the IS/OS layer in the subfoveal area. The RPE layer was extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. SS-OCTA of the SCP and the DCP layers of the same eye showed vascular rarefaction and reduced vessel density. These changes were most pronounced in the DCP layer. SS-OCTA at the level of the choriocapillaris showed complete loss of the vessels in the central portion of the lesion with clear view of the larger choroidal vessels. This peculiar configuration could be explained by severe atrophy of the choriocapillaris and Sattler's layer, and visualization of an anteriorly displaced Haller's layer to the level of the choriocapillaris. The central region was surrounded by an annulus of hypointense flow-void areas and vessel rarefaction (arrows). The LE had a similar lesion though slightly smaller in size (3DD) and less advanced in terms of the extent of geographic atrophy. SS-OCT of the same eye showed fairly preserved ELM though disrupted IS/OS layer and marked RPE thinning. The diffuse atrophy of the choriocapillaris resulted in irregular thickening of the choroid with loss of the normal bowl-shaped configuration of the choroidoscleral junction. SS-OCTA of the LE reflected the relatively less advance disease compared to the RE, especially in the choriocapillaris layer which showed multiple flow-void areas but with less diffuse atrophy than noted in the RE (**Figures 3** and **4**).

#### **7.2. SS-OCT and SS-OCTA findings in Best's disease and adult-onset vitelliform foveomacular dystrophy**

Case 3. Adult-onset vitelliform foveomacular dystrophy. A 61-year-old female presented with defective vision in the RE of approximately 6-month duration. Her BCVA was 20/100 and 20/400 in the RE and the LE, respectively. Fundus examination of the RE revealed a subfoveal plaque of amorphous yellowish-white material surrounded by numerous satellite lesions varying in size and in shape, and scattered in the anatomic macula region. On the corresponding FFA, the sub-foveal lesion showed blocked hypofluorescence with multiple pinpoint hyperfluorescent spots due to leakage within PED. The satellite lesions seen in the color

FFA, the lesion seen in the color photograph demonstrated that the RPE in the center of the lesion has virtually disappeared with unveiling of the underlying large choroidal vessels. More peripheral areas of the lesion demonstrated transmission fluorescence. SS-OCT of the same eye showed foveal thinning, wiping-out of the ELM, and the IS/OS layer in the subfoveal area. The RPE layer was extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. SS-OCTA of the SCP and the DCP layers of the same eye showed vascular rarefaction and reduced vessel density. These changes were most pronounced in the DCP layer. SS-OCTA at the level of the choriocapillaris showed complete loss of the vessels in the central portion of the lesion with clear view of the larger choroidal vessels. This peculiar configuration could be explained by severe atrophy of the choriocapillaris and Sattler's layer, and visualization of an anteriorly displaced Haller's layer to the level of the choriocapillaris. The central region was surrounded by an annulus of hypointense flow-void areas and vessel rarefaction (arrows). The LE had a similar lesion though slightly smaller in size (3DD) and less advanced in terms of the extent of geographic atrophy. SS-OCT of the same eye showed fairly preserved ELM though disrupted IS/OS layer and marked RPE thinning. The diffuse atrophy of the choriocapillaris resulted in irregular thickening of the choroid with loss of the normal bowl-shaped configuration of

in the SCP, the DCP, and the choriocapillaris.

10 OCT - Applications in Ophthalmology

**Figure 2.** Case 1. Top left, color photograph of the LE of the same patient as in **Figure 1**. The fundus shows identical lesions to those seen in the RE though less numerous. Bottom left, radial scan SS-OCT reveals foveal thinning (144 μ), disrupted ELM and IS/OS photoreceptors junction, and thinning of the choriocapillaris with enhanced visualization of the larger choroidal vessels. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers demonstrate vascular rarefaction. Affection is more pronounced in the DCP layer. The choriocapillaris shows multiple black areas of flow voids. The corresponding flow density maps show a reduced vessel density that corresponds to vascular rarefaction

> **Figure 3.** Case 2. Top left, color photograph and FFA of the RE of a 58-year-old female in late stage of Stargardt's disease. The fundus shows a sharply circumscribed area of geographic atrophy occupying the macula, approximately 4 DD in size. On FFA, the RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels. More peripheral areas of the lesion demonstrated transmission fluorescence. Bottom left, high-definition line scan (12.0 mm) SS-OCT of the same eye shows marked foveal thinning (84 μ), wiping out of the ELM and the IS/OS layer in the sub-foveal area. The RPE layer is extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers show vascular rarefaction and reduced vessel density. These changes are most pronounced in the DCP layer. The choriocapillaris shows complete loss of vessels in the central portion of the lesion with clear view of the larger choroidal vessels. The central region is surrounded by an annulus of hypointense flow-void areas and vessel rarefaction (arrows).

**Figure 4.** Case 2. Top left, color photograph and FFA of the LE of the same patient as in **Figure 3**. The fundus shows a sharply circumscribed area of geographic atrophy occupying the macula, approximately 3 DD in size. FFA in the macular area demonstrated transmission fluorescence due to marked RPE attenuation. Bottom left, high-definition line scan (12.0 mm) SS-OCT of the same eye shows foveal thinning (177 μ), wiping out of the IS/OS layer in the sub foveal area. The RPE layer was extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. The diffuse atrophy of the choriocapillaris resulted in irregular thickening of the choroid with loss of the normal bowl-shaped configuration of the choroidoscleral junction. Sub-foveal choroidal thickness is 257 μ. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers show vascular rarefaction and reduced vessel density. These changes are most pronounced in the DCP layer. The choriocapillaris shows vascular rarefaction with development of multiple hypointense flow-void areas.

Case 4. Cicatricial stage of Best's disease. A 30-year-old female presented with defective vision in both eyes of 3–6 months duration. Her BCVA was 20/80 and 20/100 in the RE and the LE, respectively. Fundus examination of the LE revealed a sub-foveal sharply circumscribed ovoid area of RPE changes with central scarring. The lesion measured approximately 1 DD. On the corresponding FFA, the lesion seen in the color photograph demonstrated transmitted fluorescence due to RPE attenuation with late staining of scar tissue. The RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels in earlier phases of the angiogram. SS-OCT of the same eye showed marked thinning of the fovea with a hyper-reflective scar tissue replacing the sub-foveal outer retinal layers, the choriocapillaris, and extending well into the underlying choroid. The immediate para-foveal area showed a sub-retinal pouch of optically lucent space with optically opaque sub-retinal clumps representative of degenerative changes peculiar of an earlier vitelliruptive stage. SS-OCTA of the DCP layer showed extensive vascular rarefaction in the area previously occupied by the vitelliform material. The choriocapillaris shows a central hypointense flow-void area surrounded by an outer zone of vascular rarefaction. The RE had rather similar fundus changes. The corresponding FFA revealed foveal RPE atrophy with on outer rim of blocked fluorescence due

**Figure 5.** Case 3. Color photograph and FFA of the RE and the LE of a 61-year-old female in the vitelliruptive stage of Best's disease. The fundus of the RE shows a sub-foveal plaque of amorphous yellowish-white material surrounded by numerous satellite lesions varying in size and shape, and scattered in the anatomic macula. On the corresponding FFA, the sub-foveal lesion shows blocked hypofluorescence with multiple pin-point hyperfluorescent spots due to leakage within PED. The satellite lesions seen in the color photograph demonstrate hyperfluorescence caused by a combination of staining, pooling in PED, and transmission fluorescence due to RPE atrophy. The LE had rather similar fundus

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Case 5. CNV complicating cicatricial stage of Best's disease. A 28-year-old female complaining of recent diminution of vision in the RE 10 days ago. Her BCVA was 20/80 and 20/400 in the RE and the LE, respectively. Fundus examination of the RE showed an area of shallow neurosensory detachment in the foveal region, approximately 1.5 DD. The lesion showed yellowish-white precipitates gravitating in its inferior portion. On FFA, the lesion seen in the color photograph demonstrated early well-defined disc-shaped hyperfluorescence inferiorly with progressively increasing fluorescence intensity suggestive of classic CNV formation. The lesion was surrounded by diffuse and fuzzy hyperfluorescence due to pooling in

to RPE hyperplasia (**Figures 7** and **8**).

changes though FFA revealed more extensive RPE atrophy.

photograph demonstrated hyperfluorescence caused by a combination of staining, pooling in PED, and transmission fluorescence due to RPE atrophy. SS-OCT of the same eye showed a dome-shaped hyper-reflective sub-foveal lesion corresponding to the yellowish vitelliform deposits seen in the color fundus photograph. The entire lesion was optically opaque except for a small optically lucent area caused by breakdown of the vitelliform material. The underlying RPE was thickened and irregular with multiple PED formation and marked thinning of the underlying choriocapillaris. SS-OCTA of the SCP layer was essentially normal in appearance apart from irregularity of the FAZ (arrow) and scattered flow-void areas (circles). The DCP layer showed centrifugal displacement of the peri-foveal vessels with extensive vascular rarefaction and enlargement of the FAZ (arrows). The para-foveal area showed hyperintense signal derived from abnormally high flow within the overcrowded vessels due to lateral displacement by the vitelliform material (asterisk). The choriocapillaris showed patchy hypointense areas that corresponded to the abovementioned vitelliform lesions. The hypointense signal might represent flow-void areas due to choriocapillaris atrophy or due to masking by the vitelliform material. The LE had rather similar fundus changes though FFA revealed more extensive RPE atrophy (**Figures 5** and **6**).

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**Figure 5.** Case 3. Color photograph and FFA of the RE and the LE of a 61-year-old female in the vitelliruptive stage of Best's disease. The fundus of the RE shows a sub-foveal plaque of amorphous yellowish-white material surrounded by numerous satellite lesions varying in size and shape, and scattered in the anatomic macula. On the corresponding FFA, the sub-foveal lesion shows blocked hypofluorescence with multiple pin-point hyperfluorescent spots due to leakage within PED. The satellite lesions seen in the color photograph demonstrate hyperfluorescence caused by a combination of staining, pooling in PED, and transmission fluorescence due to RPE atrophy. The LE had rather similar fundus changes though FFA revealed more extensive RPE atrophy.

Case 4. Cicatricial stage of Best's disease. A 30-year-old female presented with defective vision in both eyes of 3–6 months duration. Her BCVA was 20/80 and 20/100 in the RE and the LE, respectively. Fundus examination of the LE revealed a sub-foveal sharply circumscribed ovoid area of RPE changes with central scarring. The lesion measured approximately 1 DD. On the corresponding FFA, the lesion seen in the color photograph demonstrated transmitted fluorescence due to RPE attenuation with late staining of scar tissue. The RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels in earlier phases of the angiogram. SS-OCT of the same eye showed marked thinning of the fovea with a hyper-reflective scar tissue replacing the sub-foveal outer retinal layers, the choriocapillaris, and extending well into the underlying choroid. The immediate para-foveal area showed a sub-retinal pouch of optically lucent space with optically opaque sub-retinal clumps representative of degenerative changes peculiar of an earlier vitelliruptive stage. SS-OCTA of the DCP layer showed extensive vascular rarefaction in the area previously occupied by the vitelliform material. The choriocapillaris shows a central hypointense flow-void area surrounded by an outer zone of vascular rarefaction. The RE had rather similar fundus changes. The corresponding FFA revealed foveal RPE atrophy with on outer rim of blocked fluorescence due to RPE hyperplasia (**Figures 7** and **8**).

photograph demonstrated hyperfluorescence caused by a combination of staining, pooling in PED, and transmission fluorescence due to RPE atrophy. SS-OCT of the same eye showed a dome-shaped hyper-reflective sub-foveal lesion corresponding to the yellowish vitelliform deposits seen in the color fundus photograph. The entire lesion was optically opaque except for a small optically lucent area caused by breakdown of the vitelliform material. The underlying RPE was thickened and irregular with multiple PED formation and marked thinning of the underlying choriocapillaris. SS-OCTA of the SCP layer was essentially normal in appearance apart from irregularity of the FAZ (arrow) and scattered flow-void areas (circles). The DCP layer showed centrifugal displacement of the peri-foveal vessels with extensive vascular rarefaction and enlargement of the FAZ (arrows). The para-foveal area showed hyperintense signal derived from abnormally high flow within the overcrowded vessels due to lateral displacement by the vitelliform material (asterisk). The choriocapillaris showed patchy hypointense areas that corresponded to the abovementioned vitelliform lesions. The hypointense signal might represent flow-void areas due to choriocapillaris atrophy or due to masking by the vitelliform material. The LE had rather similar fundus changes though FFA revealed more

**Figure 4.** Case 2. Top left, color photograph and FFA of the LE of the same patient as in **Figure 3**. The fundus shows a sharply circumscribed area of geographic atrophy occupying the macula, approximately 3 DD in size. FFA in the macular area demonstrated transmission fluorescence due to marked RPE attenuation. Bottom left, high-definition line scan (12.0 mm) SS-OCT of the same eye shows foveal thinning (177 μ), wiping out of the IS/OS layer in the sub foveal area. The RPE layer was extremely rarified with extensive loss of the choriocapillaris and enhanced visualization of the underlying choroidal vessels. The diffuse atrophy of the choriocapillaris resulted in irregular thickening of the choroid with loss of the normal bowl-shaped configuration of the choroidoscleral junction. Sub-foveal choroidal thickness is 257 μ. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The SCP and the DCP layers show vascular rarefaction and reduced vessel density. These changes are most pronounced in the DCP layer. The choriocapillaris shows vascular

extensive RPE atrophy (**Figures 5** and **6**).

rarefaction with development of multiple hypointense flow-void areas.

12 OCT - Applications in Ophthalmology

Case 5. CNV complicating cicatricial stage of Best's disease. A 28-year-old female complaining of recent diminution of vision in the RE 10 days ago. Her BCVA was 20/80 and 20/400 in the RE and the LE, respectively. Fundus examination of the RE showed an area of shallow neurosensory detachment in the foveal region, approximately 1.5 DD. The lesion showed yellowish-white precipitates gravitating in its inferior portion. On FFA, the lesion seen in the color photograph demonstrated early well-defined disc-shaped hyperfluorescence inferiorly with progressively increasing fluorescence intensity suggestive of classic CNV formation. The lesion was surrounded by diffuse and fuzzy hyperfluorescence due to pooling in

**Figure 6.** Case 3. Left, radial scan SS-OCT of the RE of the same patient as in **Figure 5**. Note the dome-shaped hyperreflective sub-foveal lesion. The entire lesion is optically opaque except for a small optically lucent area caused by breakdown of the vitelliform material. The underlying RPE is thickened and irregular with multiple PED formation and marked thinning of the underlying choriocapillaris. Sub-foveal choroidal thickness measured 159 μ. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 4.5 × 4.5 mm field (upper row), and the corresponding flow density maps (lower row). The SCP layer is essentially normal in appearance apart from irregularity of the FAZ (arrow) and scattered flow-void areas (circles). The DCP layer shows centrifugal displacement of the perifoveal vessels with extensive vascular rarefaction and enlargement of the FAZ (arrows). Note the hyperintense signal derived from abnormally high flow within overcrowded vessels in the para-foveal area (asterisk). The choriocapillaris shows patchy hypointense flow-void areas that corresponded to the location of the abovementioned vitelliform lesions.

the neurosensory detachment cavity. An inferior rim of transmission fluorescence is noted. SS-OCT of the same eye showed sub-foveal shallow neurosensory detachment with hyperreflective amorphous lesion, along with disrupted outer retinal layers and marked atrophy of the RPE. SS-OCTA of the DCP layer showed vascular rarefaction in the area previously occupied by the vitelliform material. The normally avascular outer retina showed a para-central hyperintense signal characteristic of active CNV formation. The LE had a macular scar with

**Figure 8.** Case 4. Left, radial scan SS-OCT of the LE of the same patient as in **Figure 7**. Note marked thinning of the fovea with a hyper-reflective scar tissue replacing the sub-foveal outer retinal layers, the choriocapillaris, and extending well into the underlying choroid. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The DCP layer shows extensive vascular rarefaction in the area previously occupied by the vitelliform material. The choriocapillaris shows a central hypointense

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Case 6. CNV complicating cicatricial stage of Best's disease. A 9-year-old male presented to our clinic complaining of recent diminution of vision in the RE of few days duration. The patient was a known case of Best's disease. His BCVA was 20/200 and 20/400 in the RE and the LE, respectively. Fundus biomicroscopy examination of both eyes showed the typical scrambled-egg lesion occupying the macular area. The lesion was surrounded by residual neurosensory detachment and showed inferior migration of yellowish material and RPE alteration. The entire lesion measured approximately 2 DD in size. In the RE, the inferior portion of the scrambled-egg lesion was surrounded by a ring of deep retinal hemorrhage. FFA of both eyes demonstrated stippled fluorescence pattern due to RPE alteration, late staining of the yellowish material, and pooling of the dye in the neurosensory detachment but without conclusive evidence of CNV formation. SS-OCT of both eyes showed the typical dome-shaped hyperreflective lesion at the level of RPE extending into—and surrounded by—empty sub-retinal space. On the other hand, SS-OCTA of the RE at the plane of the outer retina demonstrated

corresponding transmission fluorescence on FFA (**Figures 9** and **10**).

flow-void area surrounded by an outer zone of vascular rarefaction.

**Figure 7.** Case 4. Color photograph and FFA of the RE and the LE of a 30-year-old female in the cicatricial stage of Best's disease. The fundus of the LE reveals a sub-foveal sharply circumscribed ovoid area of RPE changes with central scarring. The lesion measures approximately 1 DD. On the corresponding FFA, the lesion demonstrates transmitted fluorescence due to RPE attenuation with late staining of scar tissue. The RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels in earlier phases of the angiogram. The RE shows rather similar fundus changes. The corresponding FFA reveals foveal RPE atrophy with an outer rim of blocked fluorescence due to RPE hyperplasia.

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**Figure 8.** Case 4. Left, radial scan SS-OCT of the LE of the same patient as in **Figure 7**. Note marked thinning of the fovea with a hyper-reflective scar tissue replacing the sub-foveal outer retinal layers, the choriocapillaris, and extending well into the underlying choroid. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The DCP layer shows extensive vascular rarefaction in the area previously occupied by the vitelliform material. The choriocapillaris shows a central hypointense flow-void area surrounded by an outer zone of vascular rarefaction.

the neurosensory detachment cavity. An inferior rim of transmission fluorescence is noted. SS-OCT of the same eye showed sub-foveal shallow neurosensory detachment with hyperreflective amorphous lesion, along with disrupted outer retinal layers and marked atrophy of the RPE. SS-OCTA of the DCP layer showed vascular rarefaction in the area previously occupied by the vitelliform material. The normally avascular outer retina showed a para-central hyperintense signal characteristic of active CNV formation. The LE had a macular scar with corresponding transmission fluorescence on FFA (**Figures 9** and **10**).

Case 6. CNV complicating cicatricial stage of Best's disease. A 9-year-old male presented to our clinic complaining of recent diminution of vision in the RE of few days duration. The patient was a known case of Best's disease. His BCVA was 20/200 and 20/400 in the RE and the LE, respectively. Fundus biomicroscopy examination of both eyes showed the typical scrambled-egg lesion occupying the macular area. The lesion was surrounded by residual neurosensory detachment and showed inferior migration of yellowish material and RPE alteration. The entire lesion measured approximately 2 DD in size. In the RE, the inferior portion of the scrambled-egg lesion was surrounded by a ring of deep retinal hemorrhage. FFA of both eyes demonstrated stippled fluorescence pattern due to RPE alteration, late staining of the yellowish material, and pooling of the dye in the neurosensory detachment but without conclusive evidence of CNV formation. SS-OCT of both eyes showed the typical dome-shaped hyperreflective lesion at the level of RPE extending into—and surrounded by—empty sub-retinal space. On the other hand, SS-OCTA of the RE at the plane of the outer retina demonstrated

**Figure 7.** Case 4. Color photograph and FFA of the RE and the LE of a 30-year-old female in the cicatricial stage of Best's disease. The fundus of the LE reveals a sub-foveal sharply circumscribed ovoid area of RPE changes with central scarring. The lesion measures approximately 1 DD. On the corresponding FFA, the lesion demonstrates transmitted fluorescence due to RPE attenuation with late staining of scar tissue. The RPE in the center of the lesion has virtually disappeared with unveiling of the large choroidal vessels in earlier phases of the angiogram. The RE shows rather similar fundus changes. The corresponding FFA reveals foveal RPE atrophy with an outer rim of blocked fluorescence due to RPE hyperplasia.

**Figure 6.** Case 3. Left, radial scan SS-OCT of the RE of the same patient as in **Figure 5**. Note the dome-shaped hyperreflective sub-foveal lesion. The entire lesion is optically opaque except for a small optically lucent area caused by breakdown of the vitelliform material. The underlying RPE is thickened and irregular with multiple PED formation and marked thinning of the underlying choriocapillaris. Sub-foveal choroidal thickness measured 159 μ. Right, en face SS-OCTA projection of the SCP, the DCP, and the choriocapillaris in a 4.5 × 4.5 mm field (upper row), and the corresponding flow density maps (lower row). The SCP layer is essentially normal in appearance apart from irregularity of the FAZ (arrow) and scattered flow-void areas (circles). The DCP layer shows centrifugal displacement of the perifoveal vessels with extensive vascular rarefaction and enlargement of the FAZ (arrows). Note the hyperintense signal derived from abnormally high flow within overcrowded vessels in the para-foveal area (asterisk). The choriocapillaris shows patchy hypointense flow-void areas that corresponded to the location of the abovementioned vitelliform lesions.

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**Figure 9.** Case 5. Color photograph and FFA of the RE and the LE of a 28-year-old female with CNV secondary to cicatricial stage of Best's disease. The fundus of the RE shows an area of shallow neurosensory detachment in the foveal region, approximately 1.5 DD. The lesion shows yellowish-white precipitates gravitating in its inferior portion. The corresponding FFA demonstrates early well-defined disc-shaped hyperfluorescence inferiorly with progressively increasing fluorescence intensity suggestive of classic CNV. The LE had a macular scar with corresponding transmission fluorescence on FFA.

**Figure 11.** Case 6. Left, color fundus photograph and FFA of the RE shows a scrambled-egg lesion of vitelliform macular dystrophy surrounded by residual neurosensory detachment. The entire lesion measures approximately 2 DD in size. Note the inferior migration of the yellowish material with a ring of deep retinal hemorrhage (arrow). The corresponding FFA in arteriovenous phase of the same eye shows early transmitted fluorescence corresponding to RPE mottling seen in color photograph. Late phases of FFA show staining of the scrambled-egg lesion and residual sub-retinal yellowish deposits. Note the late pooling of the dye into the neurosensory detachment seen at the inferior edge of the vitelliform

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**Figure 12.** Case 6. Left, en face SS-OCTA projection of the outer retina and the corresponding flow density map in a 3 × 3 mm field of the RE of the same patient as in **Figure 11**. Note the hyperintense signal due to high flow within an interlacing curvilinear neovascular tuft characteristic of active CNV. Note the bright red color code denoting high vessel density. Corresponding SS-OCT shows the hyper-reflective lesion in the sub-retinal space. Right, en face SS-OCTA projection of the outer retina and the corresponding flow density map in a 3 × 3 mm field of the LE demonstrating hyperintense signal due to flow within an inactive lesion (vascularized disciform scar). Note the much less vessel density represented by a faint yellow color code compared to the RE signal intensity. The quality of SS-OCTA image of the LE is degraded by motion artifacts due to poor fixation. Corresponding SS-OCT shows the hyper-reflective lesion in the sub-retinal space.

lesion. Right, color fundus photograph and FFA of the LE show essentially similar features to the RE.

**Figure 10.** Case 5. Left, radial scan SS-OCT of the RE of the same patient as in **Figure 9**. Note the sub-foveal shallow neurosensory detachment with hyper-reflective amorphous lesion, along with disrupted outer retinal layers and marked atrophy of the RPE. Right, en face SS-OCTA projection of the SCP, the DCP, and the outer retina in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The DCP layer shows vascular rarefaction in the area previously occupied by the vitelliform material. The outer retina shows a Para-central hyperintense signal characteristic of active CNV formation.

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**Figure 11.** Case 6. Left, color fundus photograph and FFA of the RE shows a scrambled-egg lesion of vitelliform macular dystrophy surrounded by residual neurosensory detachment. The entire lesion measures approximately 2 DD in size. Note the inferior migration of the yellowish material with a ring of deep retinal hemorrhage (arrow). The corresponding FFA in arteriovenous phase of the same eye shows early transmitted fluorescence corresponding to RPE mottling seen in color photograph. Late phases of FFA show staining of the scrambled-egg lesion and residual sub-retinal yellowish deposits. Note the late pooling of the dye into the neurosensory detachment seen at the inferior edge of the vitelliform lesion. Right, color fundus photograph and FFA of the LE show essentially similar features to the RE.

**Figure 12.** Case 6. Left, en face SS-OCTA projection of the outer retina and the corresponding flow density map in a 3 × 3 mm field of the RE of the same patient as in **Figure 11**. Note the hyperintense signal due to high flow within an interlacing curvilinear neovascular tuft characteristic of active CNV. Note the bright red color code denoting high vessel density. Corresponding SS-OCT shows the hyper-reflective lesion in the sub-retinal space. Right, en face SS-OCTA projection of the outer retina and the corresponding flow density map in a 3 × 3 mm field of the LE demonstrating hyperintense signal due to flow within an inactive lesion (vascularized disciform scar). Note the much less vessel density represented by a faint yellow color code compared to the RE signal intensity. The quality of SS-OCTA image of the LE is degraded by motion artifacts due to poor fixation. Corresponding SS-OCT shows the hyper-reflective lesion in the sub-retinal space.

**Figure 10.** Case 5. Left, radial scan SS-OCT of the RE of the same patient as in **Figure 9**. Note the sub-foveal shallow neurosensory detachment with hyper-reflective amorphous lesion, along with disrupted outer retinal layers and marked atrophy of the RPE. Right, en face SS-OCTA projection of the SCP, the DCP, and the outer retina in a 6 × 6 mm field (upper row), and the corresponding flow density maps (lower row). The DCP layer shows vascular rarefaction in the area previously occupied by the vitelliform material. The outer retina shows a Para-central hyperintense signal

**Figure 9.** Case 5. Color photograph and FFA of the RE and the LE of a 28-year-old female with CNV secondary to cicatricial stage of Best's disease. The fundus of the RE shows an area of shallow neurosensory detachment in the foveal region, approximately 1.5 DD. The lesion shows yellowish-white precipitates gravitating in its inferior portion. The corresponding FFA demonstrates early well-defined disc-shaped hyperfluorescence inferiorly with progressively increasing fluorescence intensity suggestive of classic CNV. The LE had a macular scar with corresponding transmission

characteristic of active CNV formation.

fluorescence on FFA.

16 OCT - Applications in Ophthalmology

a distinct active neovascular complex which appeared as a small tuft of bright high-flow (hyperintense signal) curvilinear vessels, whereas SS-OCTA of the LE at the plane of the outer retina demonstrated flow within inactive lesion (vascularized disciform scar). It is worth noting that in this case, both FFA and SS-OCT were inconclusive in confirming the diagnosis and the state of activity of CNV; meanwhile, SS-OCTA unequivocally displayed active CNV in the RE and vascularized disciform scar in the LE (**Figures 11** and **12**).

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