Ординатура / Офтальмология / Английские материалы / Optical Coherence Tomography in Age-Related Macular Degeneration_Coscas_2009

Clinical and Biomicroscopic Signs

A 73-year-old woman presented with minor symptoms in the right eye and a slight relative reduction of visual acuity. VA RE: 20/40 - VA LE: 20/80.

Biomicroscopic examination revealed several mediumsized soft drusen, predominantly perifoveal, but no SRF, hemorrhage, or hard exudates.

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Autofluorescence Reference Image

No alteration of xanthophyll pigment. Presence of a minimal, oval-shaped, hyper-fluorescence at the temporal macular area suggesting a macular lesion.

Fluorescein Angiography

Progressive, heterogeneous, and poorly-delineated macular hyper-fluorescence over 2 DD, masked in its center by xanthophyll pigment with late fluorescein leakage and pinpoints.

SLO-ICG Angiography

Vast, rounded, poorly-delineated hyper-fluorescent area occupying the entire subfoveal zone and suggesting a neovascular network within the dark PED (Figure 7).

Suggested Angiographic Diagnosis:

Small area of occult CNV within a vascularized PED.

At the RPE Level

Presence of a regular, moderately large elevation, composed of multiple flat domes with a wavy appearance, suggestive of fairly extensive flat PED in the fovea.

This PED was relatively flat, allowing good visibility of Bruch’s membrane. The RPE band was occasionally slightly thinned.

The PED cavity was hypo-reflective and almost optically empty and slightly more organized in the nasal sector. The PED had induced partial and moderate posterior shadowing.

Anterior to the RPE

The neurosensory retina was only slightly altered with good preservation of retinal structure.

The foveal depression was almost normal, confirming the recent nature of the lesion, with preservation of good visual acuity.

There was intraretinal fluid with slightly increased retinal thickness, subretinal fluid, and a subfoveal SRF.

As expected, the CNV itself was barely visible on OCT.

Diagnosis

OCT examination demonstrated a relatively small, wavy pigment epithelium detachment with a slightly reflective cavity, especially just underneath the RPE,

indicating the presence of low-density fibrovascular

tissue. Adjacent to the PED, an exudative reaction with diffuse infiltration (moderate retinal thickening)

and an SRF. The retinal layers were not disorganized.

Fluorescein angiography immediately demonstrated irregular hyper-fluorescence with pinpoints, suggestive of occult neovascularization with a false image of foveal sparing due to xanthophyll pigment.

SLO-ICG angiography confirmed the presence of

choroidal neovascularization and localized it to the subfoveal area, approximately 1.5 DD in size.

The diagnosis was therefore confirmed: recent occult

choroidal neovascularization or vascularized PED with no signs of decompensation and only moderate

symptoms at this stage (Figures 7 and 8).

Treatment was offered, but the patient preferred to wait until completion of treatment of the other much more severely affected eye.

The natural history was followed routinely, assessing the usual functional and morphological parameters for almost 3 years.

Visual acuity, initially considered to be satisfactory, slowly deteriorated, causing increasing disability.

However, this vision loss was well-tolerated and accepted

8by the patient over time, as this eye was always better than the fellow eye.

OCT examinations demonstrated relatively minor and moderate changes with no sudden complications.

Serial OCT examinations remained essentially stable, not revealing any convincing signs of marked deterioration (Figure 9a-d).

At the third month, the PED had spread with the formation of a few cystic spaces but remained relatively flat, moderately reflective, with a small SRF and a small amount of intraretinal fluid with no loss of the foveal depression (Figure 9a).

At the end of the first year, lesions had progressed: the PED was more prominent, the SRF was more extensive with diffuse intraretinal fluid causing loss of the foveal depression (Figure 9b).

However, this deterioration was only limited, as the retinal layers remained well-organized and not dissociated.

The OCT findings were practically unchanged at the end of the second year (Figure 9c).

However, at the third year, the OCT features, although similar to those of previous examinations, showed worsening of the lesions: the PED was much more extensive and had become wavy with several cysts and moderate hyper-reflectivity.

These findings were suggestive of fibrosis underneath the pigment epithelium but with no exudative reaction or disorganization of retinal layers (Figure 9d).

On angiography, the lesions remained relatively stable over time.

On fluorescein angiography, the shape of the lesion and its overall surface area, as well as pinpoint leakage remained almost unchanged with no complications, no classic CNV, and no hemorrhage.

On ICG angiography, the initially well-defined choroidal neovascularization, gradually spread to invade all of the surface area of the PED but without causing any other complications.

PED

Figure 9: Typical early occult CNV–Natural history.

c): Twp years: virtually stable appearance on angiography and OCT. Decline of visual acuity. VA: 20/100.

ICG

c

Clinical Signs

A 79-year-old patient presented with progressive and moderate decline of visual acuity in the left eye that was immediately worrying due to a longstanding fibrovascular lesion in the right eye.

VA RE: 20/640 - VA LE: 20/63.

Biomicroscopic Examination

Biomicroscopic examination showed few changes in the

8macular region, limited to a few soft drusen in the temporal macular zone.

Autofluorescence

Autofluorescence visualized reticular drusen in the region of the superior temporal arcade and a small inferior juxtafoveal hyper-fluorescent zone (Figure 10).

Fluorescein and ICG Angiography

Fluorescein angiography: progressive hyper-fluorescence with pinpoint fluorescein leakage in the inferior and temporal region, masked by xanthophyll pigment in its center.

SLO-ICG angiography: vast hypo-fluorescent area, suggesting the presence of a heterogeneous, irregular, subfoveal PED, but well-delineated on late phases and surrounded by several soft drusen (Figure 10).

Suggested Angiographic Diagnosis:

Recent decompensation of a vascularized PED

with the characteristic appearance of small occult

CNV without hemorrhage on fluorescein angiog-

raphy.

Stratus* horizontal section

At the RPE level, a small temporal PED is present, extending as far as the fovea. This PED had an irregular appearance with several cysts. The PED cavity was moderately reflective but homogeneous.

Anterior to the RPE, the neurosensory retina was only slightly modified with relative preservation of the retinal structure. However, it was diffusely thickened by intraretinal fluid predominantly in the outer layers and also subretinal fluid

Vertical section

The PED was visible but appeared to be fairly flat on the vertical section.

In contrast, the SRF was more extensive with marked settling of intraretinal fluid (Figure 11).

The foveal depression was relatively unchanged, confirming the recent nature of the lesion with preservation of good visual acuity.

Diagnosis

The OCT examination demonstrated a small, ir-

regular, heterogeneous, and fairly flat pigment epithelium detachment with a moderately reflec-

tive cavity.

An exudative reaction with moderately increased

retinal thickness and a small subfoveal SRF was

demonstrated adjacent to the PED, and the retinal layers were not disorganized.

These features are typical of recent small occult CNV

Fluorescein angiography was highly suggestive of this lesion, indicating early decompensation in this eye.

SLO-ICG angiography confirmed these findings and reaffirmed the diagnosis.

This recent lesion with moderate symptoms justified immediately anti-VEGF therapy in an attempt to prevent progression.

Anti-VEGF therapy was administered by repeated intravitreal injections over a period of 18 months due to persistent PED and downward shifting SRF. There was a certain degree of extension of the angiographic lesions contrasting with slow improvement and stabilization of the symptoms Visual acuity varied in parallel with treatment: several moderate variations with initial improvement followed by slight deterioration, each time that treatment was stopped. Treatment was therefore administered every 2 months to restore visual acuity to 20/40.

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Clinical Features

Lesions slowly deteriorated: autofluorescence photographs showed extension of the lesion and the hyperfluorescent halo (Figure 12a).

TD-OCT examinations (using the Stratus* during the first year) demonstrated the course of intraretinal and subretinal fluid and the PED.

▬The overall aspect of OCT sections appeared to accurately reflect partial resolution of exudation during the first 3 months but with persistence of shifting fluid (Figure 12b).

▬After a brief phase of paradoxical deterioration, the third injection provided marked improvement.

▬Injections were subsequently performed every 2 to 3 months due to recurrence of symptoms or morphological changes on the various imaging modalities.

▬At the end of the first year and after 6 intravitreal injections, the retina had normal thickness and organization (contrasting slightly with the angiographic appearance). The PED had collapsed with slight fibrosis and moderate reflectivity (Figure 12c).

▬However, during the second year, although the lesions appeared to be stabilized, the patient experienced a relapse marked by recurrence of intraretinal fluid.

Spectralis* SD-OCT demonstrated changes such as: alterations of the IS/OS interface and external limiting membrane, disrupted or thickened in various places over the vascularized PED.

The outer nuclear layer was invaded by a denser material and bright hyper-reflective spots suggesting recurrent CNV (Figure 12d).

Anti-VEGF therapy was therefore continued with one injection every 2 months allowing functional (VA: 20/40) and morphological stabilization.

On fluorescein angiography, the irregular hyper-fluo- rescence and pinpoints became increasingly visible, occupying all of the foveal region but with no increase of its overall surface area. All the occult CNV persisted and appeared to become stabilized during treatment with neither complications nor new hemorrhages.

On ICG angiography, the overall surface area of the vascularized PED remained stable. The CNV was increasingly visible and gradually occupied all of the PED.

This persistence of the PED did not appear to be due to a new complication, but rather to slow scarring.

Overall, this case presented a favorable course, despite

recurrences and persistence of the PED, with shifting

SRF and slight extension of the angiographic lesions.

These features indicated the need for prolonged

treatment with repeated anti-VEGF IVT injections for

18 months.

Spectral-Domain OCT

Spectral-Domain OCT analysis of the outer retinal layers allowed monitoring of the course of this clinical case and the effects of choroidal neovascularization and the vascularized PED on the photoreceptors themselves.

Signs of recurrence were observed at the time of the 7th injection:

▬The IS/OS interface was no longer visible over the dome of the PED.

8▬ In the subfoveal region, the IS/OS interface was replaced by a zone of hyper-reflectivity and several

temporal bright hyper-reflective spots (Figure 13a).

After each of the following injections

▬These abnormalities gradually resolved with return of a continuous IS/OS interface (Figure 13b).

Conclusion

This typical, moderately large, occult CNV lesion with recent decompensation marked by loss of visual acuity and subretinal and intraretinal fluid, justified treatment with repeated IVT injections of anti-VEGF.

Throughout the course, with a current follow-up of 18 months, the response to treatment was generally satisfactory but always partial and incomplete, marked by several recurrences.

Treatment corresponded to the usual regimen: first a

series of 3 injections followed by injections as required, according to the imaging findings and visual acuity.

Injections were therefore repeated every 2 to 3 months, depending on the results of these examinations. The current result is overall satisfactory with visual acuity maintained at 20/40.

▬Bright hyper-reflective spots became smaller and less numerous and then became considerably rarer (Figure 13b, c, and d).

▬The outer nuclear layer gradually regained almost normal thickness and reflectivity (Figure 13d). [Note that the fourth section is slightly eccentric downwards, which gives a false impression of regression of the PED itself].

▬The PED persisted, but was flatter, wavy, and hyporeflective.

▬A small SRF persisted and remained detectable throughout the course, but all retinal layers regained an almost normal organization (Figure 13d).

▬The vitreous appeared to be detached at this stage of the disease (Figure 13d).

However, the PED, although flattened, still persisted

with a characteristic wavy profile and no marked fibrosis.

A layer of subretinal fluid remains visible and has never completely resolved.

Analysis of the outer retinal layers demonstrated marked changes during active phases (disruption of the IS/OS interface, bright hyper-reflective spots and progressive return to normal with successive treatment sessions in parallel with improvement of visual acuity, indicating a favorable prognosis at this stage.

However, persistence of intraretinal fluid and the PED justifies prolonged observation for a currently undefined duration.