Chronic Visual Loss (OSCE focused)

Candidate Instructions: You are a final-year medical student in the GP clinic. A 72-year-old patient attends complaining of gradual visual deterioration over the last year. Take a focused history, perform an appropriate examination (as directed), and discuss your likely differential diagnosis and initial management plan.

Key History Points 📝

• ⏱️ Onset & Progression: Gradual or stepwise? Symmetrical or asymmetrical?
• 📍 Laterality: One eye vs both eyes.
• 🔎 Quality: Blurring, central vs peripheral loss, glare/halos, distortion (metamorphopsia).
• ⚡ Associated Symptoms: Floaters, flashing lights, eye pain, night blindness, photophobia.
• 📜 PMHx: Diabetes, hypertension, glaucoma, previous eye surgery or trauma.
• 💊 Drugs: Steroids (can cause cataracts & glaucoma).
• 👪 Family history: Glaucoma, macular degeneration, retinal disease.
• ⚖️ Functional impact: Driving, reading, falls risk.

Focused Examination 👀

• 🎯 Visual acuity (Snellen chart).
• 🖐️ Visual fields (confrontation or perimetry).
• 💡 Pupillary reflexes (afferent defect?).
• 🔬 Fundoscopy (lens opacities, optic disc cupping, retinal changes, macular degeneration).

Key Differentials ⚖️

Investigations 🔬

• 🧪 Bloods: HbA1c (diabetes), ESR/CRP if suspect inflammatory disease.
• 👁️ Ophthalmic tests: Optical coherence tomography (OCT), intraocular pressure, slit-lamp exam.
• 🧠 Imaging (MRI/CT) if optic nerve compression or atypical features.

Management 💊

• Cataract: Refer for cataract surgery when daily life is affected.
• Glaucoma: Lifelong treatment – topical prostaglandin analogues (e.g. latanoprost), sometimes surgery.
• AMD: Dry → lifestyle (smoking cessation, diet); Wet → urgent referral for intravitreal anti-VEGF injections.
• Diabetic Retinopathy: Strict glycaemic & BP control, laser therapy or anti-VEGF for proliferative disease.

Examiner’s Marking Guide 📋

• Identifies chronic, progressive course and functional impact.
• Covers key sight-threatening differentials: cataract, glaucoma, AMD, diabetic retinopathy.
• Performs focused eye exam (acuity, fields, fundoscopy).
• Recognises when urgent vs routine ophthalmology referral is needed.
• Explains management sensitively, addresses patient concerns (driving, independence).

🧑‍⚕️ Case Examples - Chronic Visual Loss

• Case 1 (Cataract): 👁️‍🗨️ A 72-year-old woman complains of progressive, painless blurring of vision over 2 years. She struggles with night driving due to glare from headlights. Fundoscopy is difficult because of lens opacity. Diagnosis: Age-related cataract. Teaching point: Painless, gradual decline in vision with glare and faded colours; treatment is surgical lens replacement.
• Case 2 (Primary Open-Angle Glaucoma): 🌫️ A 68-year-old man presents with gradual loss of peripheral vision, often described as “tunnel vision.” Intraocular pressure is raised and optic disc cupping is seen. Diagnosis: Chronic open-angle glaucoma. Teaching point: Insidious, bilateral disease causing peripheral field loss; managed with prostaglandin analogues or surgery to lower intraocular pressure.
• Case 3 (Diabetic Retinopathy): 🍬 A 60-year-old man with poorly controlled type 2 diabetes presents with gradual worsening of vision. Fundoscopy reveals microaneurysms, dot-and-blot haemorrhages, and cotton wool spots. Diagnosis: Diabetic retinopathy (background proliferative changes). Teaching point: Regular screening and tight glycaemic/BP control are key; advanced disease may require laser or intravitreal therapy.
• Case 4 (Age-Related Macular Degeneration – Wet type): 🌅 A 75-year-old woman reports distortion of central vision (straight lines appear wavy) and difficulty reading. Fundoscopy shows subretinal fluid and haemorrhage at the macula. Diagnosis: Neovascular (wet) AMD. Teaching point: Central vision loss with distortion suggests macular disease; treat wet AMD with intravitreal anti-VEGF injections.
• Case 5 (Optic Atrophy from Multiple Sclerosis): 🧠 A 45-year-old woman with a history of relapsing-remitting MS reports gradual visual decline in one eye after previous episodes of optic neuritis. Fundoscopy shows a pale optic disc. Diagnosis: Optic atrophy secondary to demyelinating disease. Teaching point: Past optic neuritis can leave residual optic atrophy; vision loss is usually irreversible, but relapse prevention is key.