Welcome back to Ready, Set, Retina! In this episode, Daniel Epshtein, OD, FAAO, is joined by Carolyn Majcher, OD, FAAO, to discuss a case of geographic atrophy (GA) and review key biomarkers of progression optometrists should be aware of.
Dr. Majcher is the Director of Residency Programs and a professor at the Oklahoma College of Optometry in Tahlequah, Oklahoma.
GA case report
An 83-year-old female patient presented to the clinic; she reported a few systemic risk factors for macular degeneration, such as hypertension and dyslipidemia, but reported never having smoked before. Her best-corrected visual acuity (BCVA) was 20/25 OU.
Figures 1 and 2: Color fundus photography (CFP) and optical coherence tomography (OCT) imaging OD, respectively; the images reveal diffuse small and medium drusen.
Figure 1: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 2: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figures 3 and 4: CFP and OCT imaging OS, respectively; note the reticular pseudodrusen (also known as subretinal drusenoid deposits [SDD]) in the fundus image and on OCT (shown as a nodular hyperreflective subretinal deposit). There are also vertical hyperreflective columns on OCT suggestive of retinal pigment epithelium (RPE) disruption.
Figure 3: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 4: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
2-year follow-up
Figure 5: CFP OS from 2 years after baseline; an extrafoveal hypopigmented area of GA with well-demarcated borders is visible.
Figure 5: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 6: OCT imaging OS from 2 years after baseline; several classic features of GA are shown, such as atrophy of the RPE and outer retina that is exposing the Bruch’s membrane and resulting in choroidal hypertransmission defects.
Figure 6: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 7: Fundus autofluorescence (FAF) imaging OS 2 years after baseline; two hypoautofluorescent areas of GA are clearly visible, demonstrating that the GA has become multifocal, which is another biomarker of progression.1 There is also a small band of hyperautofluorescence around the larger patch of GA that is closer to the optic nerve.
Figure 7: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Pearl: The general rule is that areas of hyperautofluorescence are more likely to progress because these areas signify diseased or degenerating RPE.
Prognostic value of GA phenotype FAF patterns
The GAIN study found that GA lesions with a diffuse or continuous band of hyperautofluorescence (Figures 8 and 9) were more likely to progress and / or progressed faster than lesions with no or focal areas of hyperautofluorescence (Figures 10 and 11).2
Another study found the following rates of GA lesion enlargement with the corresponding FAF abnormalities:3
- Banded hyperautofluorescence along the margin of GA: 1.81 mm2 / year
- Diffuse hyperautofluorescence along the margin of GA and elsewhere: 1.77 mm2 / year
- Focal hyperautofluorescence along the margin of GA: 0.81 mm2 / year
- No abnormalities: 0.38 mm2 / year
Figures 8 and 9: FAF images of GA lesions that are more likely to progress, such as banded GA lesions where there is hyperautofluorescence directly adjacent to the margin of GA in an almost continuous ring shape (Figure 8) or diffuse with hyperautofluorescence at the margin and elsewhere (Figure 9).
Figure 8: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 9: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figures 10 and 11: FAF imaging of GA lesions with traits that indicate they are less likely to progress or will progress more slowly, such as no abnormalities (Figure 10) or focal spots of hyperautofluorescence adjacent directly to the margin of GA (Figure 11).
Figure 10: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 11: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
4-year follow-up
The patient’s BCVA was 20/30 OU at the final follow-up.
Figure 12: CFP OS at the 4-year follow-up; the GA lesions have coalesced and expanded into the superior macular region, though the atrophy has remained extrafoveal.
Figure 12: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 13: FAF OS at the 4-year follow-up; the lesions have enlarged toward the nasal region, which was expected due to the hyperautofluorescence in this area of the lesion’s margin from the 2-year follow-up.
Figure 13: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 14: OCT OS at the 4-year follow-up; there is an enlarged area of choroidal hypertransmission compared to the 2-year scan, and some RPE disruption in the fovea.
Figure 14: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Dr. Majcher noted that FAF can be very valuable in qualitatively tracking the progression of GA area over time compared to CFP alone. Additionally, she highlighted that patients with progressing extrafoveal GA can still have relatively good BCVA, so visual acuity cannot be used as a marker of GA progression when it is nonfoveal.
Using NIR imaging to track GA
Dr. Majcher noted that for practices that do not have access to FAF, near-infrared reflectance (NIR) imaging, which is a gray-scale image generated by OCTs, also has significant utility in tracking GA progression.
Figure 15: NIR imaging OS at baseline; a small hyperreflective area of GA is visible.
Figure 15: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 16: NIR imaging OS at the 2-year follow-up; there is notable hyperreflectivity in the growing areas of GA.
Figure 16: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Figure 17: NIR imaging OS at the 4-year follow-up; the areas of hyperreflectivity have grown in size corresponding with the progression of GA.
Figure 17: Courtesy of Carolyn Majcher, OD, FAAO, FORS.
Conclusion
Multimodal imaging is critical for tracking GA progression, with FAF demonstrating significant utility in monitoring lesion growth.
It is important to identify biomarkers on multimodal imaging that may suggest either a higher risk of progression or risk of faster progression, including:
- Fundus:
- Multifocal GA lesions
- Drusen load
- Sharply demarcated lesion
- Increased visibility of the choroid
- FAF:
- Hypoautofluorescence with a sharply demarcated border
- Hyperautofluorescent bands around GA lesions1
- OCT:
- Reticular pseudodrusen (subretinal drusenoid deposits)
- Choroidal hypertransmission
- Loss of RPE or attenuation of photoreceptors
- NIR:
- Hyperreflective areas of GA
