Although lectures are excellent for establishing optometric theory, some things are easier to glean in practice. If you’re wanting to put your analytical skills to the test, join Jeffry D. Gerson, OD, FAAO, FORS; Julie Rodman, OD, MSc, FAAO, FORS; and Sara LeMay, OD, FAAO, as they take on Damon Dierker, OD, FAAO’s Wheel of Diagnosis. The rules are simple: we’ll present different case studies; all you need to do is determine each patient’s diagnosis and outline how you’d manage them. If you’re ready, let’s see where the wheel lands!
The Silent Stealer
You’re performing a routine exam on a 72-year-old patient who came in without any complaints. Her best-corrected visual acuity (BCVA) is 20/20, OD, and 20/25, OS. Considering her health, you note she doesn’t take nutritional supplements and has a history of hypertension, hyperlipidemia, and osteoporosis, alongside being a former smoker – having quit, aged 55, after 20 pack-years. She also has a mother who lost her central vision in her 80s.
The patient’s preliminary Amsler Grid demonstrates mild central distortion in both eyes; and in her fundus photography, you observe large drusen, OU, with the left eye in particular having multiple drusen larger than 125 µm. You confirm that there’s no subretinal fluid, hemorrhage, or pigment epithelial detachment; however, you struggle to see a foveal light reflex, especially in the left eye.
What are your initial thoughts regarding this patient’s diagnosis?
For all three experts, this is reflective of a case most practitioners will see every day. However, even before delving into potential diagnoses, this patient’s case history has several things that stand out. First are her age, history of smoking, and family history of vision loss, which all immediately lead Dr. Rodman to consider macular degeneration – with genetics especially being a key risk factor. And the fundus photography solidifies this worry. “We know if a patient has at least one drusen greater than 125 µm – equivalent to the size of the lumen or caliber of the central retinal vein leaving the optic nerve – they automatically have intermediate AMD, if not worse,” she explains.
But is that enough information to confidently manage this patient? Dr. Rodman argues not, highlighting that multimodal imaging, with ocular coherence tomography (OCT) and fundus autofluorescence (FAF), may be needed to unveil any geographic atrophy (GA) or choroidal neovascularisation hidden within the fundus photography. This may also help explain the visual acuity imbalance between the patient’s eyes.
But what if a condensing lens is all you have? “I certainly wouldn’t feel comfortable diagnosing, especially for that left eye, in that circumstance,” answers Dr. Rodman. “It’s so important to evaluate what’s happening underneath all this deposition; if I didn’t have the instruments needed, I’d probably refer it out.”
The Imposter
Prior to this appointment, the 45-year-old patient you’re assessing had been told she has macular degeneration. The referral you received came with a diagnosis of macular changes, OU, compared to an exam five years prior. At this appointment, her BCVA is 20/30, OD and 20/40, OS. She appears healthy – with no reports of systemic disease – isn’t taking any medications, and has never smoked. The patient does have a mother diagnosed with macular degeneration in her 60s and a sister made aware of some sort of ‘retinal problem.’ Additionally, she was given a color vision test which appeared normal.
Given all this information, what’s your assessment of this patient’s presentation?
If you’re like Dr. Gerson, you’ll first question the idea that, despite what she’s been told, this patient has AMD. As he says, “you can’t have an age-related disease without enough age.” This, plus the lack of traditional AMD biomarkers, such as deposit hyperautofluorescence, confirmed this for Dr. LeMay too. Instead, she feels the FAF pattern appears to more closely resemble inherited retinal diseases (IRDs).
But which IRD exactly? “This looks a little like Stargardt's Disease, given the retinal flecks and central loss – I wouldn't even rule out a TIMP3, Sorsby’s fundus dystrophy diagnosis,” Dr. LeMay says. “However, I’ve been fooled so often by IRDs that my preference is to avoid getting into the specific types and instead order a genetic test for more details regarding possible identifiable genetic variables.” She’d also hold off on AREDS2 supplementation, or recommending complement inhibition therapy until the genetic test comes back.
But not all practitioners are convinced this is the best avenue for diagnosis. Dr. Rodman – especially given that Stargardt's Disease isn’t common in women – would instead make use of her university’s electrodiagnostics clinic to see whether, as her initial judgment leans, this patient has a retinal pigment epithelium-pattern dystrophy, specifically spider dystrophy. However, even with differing ideas on how best to reach a diagnosis – and what that diagnosis might be, our experts all agree it’s important to avoid automatically hitting the accelerator and offering an AMD diagnosis and complement inhibition when you’re not certain.
The Detachment
An 80-year-old patient comes into your practice reporting something alarming: she suddenly can’t see out of her left eye. You don’t have much historical data, but at this appointment her BCVA is 20/50 OD and light perception OS. The information you do have highlights that she takes AREDS2 supplements and her left eye is being treated with aflibercept every 12 weeks for neovascular AMD – however, she missed her last dose, having last been treated four months ago. She also has hypertension and is a former smoker, smoking for 40 years before quitting 10 years ago.
So what happened to her left eye?
To Dr. Gerson, this case on the surface is the simplest presented so far, one whose clues point to this patient extending the time between treatment injections too far. Although he acknowledges treat-and-extend regimens are common, they’re typically done in a more controlled manner. “This is someone requiring treatment for their wet AMD and to hopefully regain some of the vision they’ve probably lost,” he explains.
So is that all that’s needed? Well, several other things give our experts pause. Dr. LeMay, for example, found herself perplexed by this patient’s OS light perception given that this eye also has a large subretinal hemorrhage, visible using OCT – another cause for specialist referral. A subretinal hemorrhage also affects the prognosis and treatment approach. “When vision goes down this far, we usually go in with a guarded prognosis,” she says. “We’ll inform the patient that their recovery might be very different. We do resume treatment until we see resolution of the bleeding and fluid, but if we’re not seeing a lot of vision recovery, we’ll discuss whether there’s any further benefit to continuing anti-VEGF therapy.”
But there are even more things to avoid overlooking. As Dr. Rodman highlights, if you only focus on the left eye, you’ll miss that the right eye appears to have potential GA encircling the fovea that may benefit from a closer look with multimodal imaging. Similarly, Dr. Gerson reminds us that although hemorrhages can certainly result in dramatic vision loss, light perception in macular degeneration isn’t normal. “Just because someone has macular degeneration doesn't mean they can't have an optic nerve event or something else that happens,” he says. “So we need to ensure we're not solely focused on the macula and recognize that other things can happen too.”
Behind the wheel
So did your assessments line up with our experts’ assessments? Whether you concurred completely or your opinions differed in places, hopefully being able to put your skills to the test alongside others has given you some new clinical pearls to hold close the next time you’re in-clinic.
Want to continue the challenge? For extra cases and our experts’ full insights, watch the VOD of the Wheel of Diagnosis!
