Welcome back to Ready, Set, Retina. In this episode, Daniel Epshtein, OD, FAAO, sits down with Raman Bhakhri, OD, FAAO, to discuss how geographic atrophy (GA) can impact functional vision and tests optometrists can use to monitor vision loss.
Dr. Bhakhri is a professor at the Illinois College of Optometry in Chicago, Illinois, with a special interest in retina, low vision, and ocular pharmacology.
Low vision in GA: A case report
A 91-year-old white female patient presented to the clinic with a complaint of difficulty reading, which had worsened over the past 2 years. The patient was a retired English teacher and avid reader. She had been diagnosed with GA in both eyes (OU) and was followed every 6 months in the clinic.
At this point, complement inhibition therapy for GA had just been approved and was not yet widely used, so she was managed under the old paradigm of monitoring without medical intervention. Her best-corrected visual acuity (BCVA) was 20/30-2 in the right eye (OD) and 20/25-2 in the left eye (OS).
Figure 1: Fundus and optical coherence tomography (OCT) imaging OD of the patient at baseline; fundus shows two atrophic lesions with pigmentary changes and drusen surrounding the lesions, while OCT highlights significant outer retinal and RPE degeneration, an area of cRORA with choroidal hypertransmission defects. The patient still has some relatively intact retinal pigment epithelium (RPE) and outer retina in the nasal aspect of her fovea, which explains why she still has relatively good vision.
Figure 1: Courtesy of Daniel Epshtein, OD, FAAO.
Figure 2: Fundus and OCT imaging OS of the patient at baseline; fundus shows one large atrophic lesion with visible choroidal vessels due to loss of the RPE. OCT demonstrates relatively intact foveal RPE and ellipsoid zone surrounded by cRORA with choroidal hypertransmission defects.
Figure 2: Courtesy of Daniel Epshtein, OD, FAAO.
Figure 3: Macular thickness map OU; the left eye demonstrates more significant retinal degeneration, and the atrophic lesions from the fundus photos correspond with the hyperreflective lesions on the infrared (IR) fundus imaging.
Figure 3: Courtesy of Daniel Epshtein, OD, FAAO.
Figure 4: Atrophic lesions on color photography and fundus autofluorescence (FAF) imaging OD; note the multifocal areas of hypoautofluorescence highlighting smaller atrophic lesions surrounding the two central lesions.
Figure 4: Courtesy of Daniel Epshtein, OD, FAAO.
Figure 5: Atrophic lesion on color photography and FAF imaging OS; note the large hypoautofluorescent lesion with a band of hyperautofluorescence inferiorly, which is a biomarker of increased risk of lesion progression.1
Figure 5: Courtesy of Daniel Epshtein, OD, FAAO.
Monitoring functional vision in GA patients
Dr. Bhakhri highlighted functional issues GA patients may experience that optometrists should be aware of, such as: central vision loss / paracentral vision loss / scotomas, low light and reading difficulties, driving, and mental health issues due to reduced vision.
Testing functional vision in GA patients can consist of a variety of exams, including:
- Visual acuity
- Snellen and ETDRS testing
- Contrast testing
- Bailey-Lovie and MARS testing
- Perimetry and microperimetry
- Static and kinetic perimetry
- Microperimetry tests the central 10 to 20° of the macula and can be used to identify the preferred retinal locus (PRL), which patients can then be trained to use for daily tasks2
- Low luminance visual acuity
To learn more about when to refer GA patients to low vision, watch the full interview!
Conclusion
Though this patient would have likely benefited from complement inhibition therapy if it had been approved earlier, it is important to look past her BCVA to understand her complaints.
Understanding the impact of geographic atrophy on functional vision is critical to providing optimal patient care, as low vision rehabilitation can offer patients tools to make navigating day-to-day life with significant vision loss easier.
