Ophthalmology 50 Facts for MRCP Part 1: Key Differences You Must Know

TL;DR: 

This clinician-written guide distils ophthalmology into 50 high-yield facts for MRCP Part 1, focusing on the differences that most often decide exam marks. It covers the five most tested subtopics, highlights common traps, and includes a short MCQ with explanation. Use it alongside the Crack Medicine hubs and question bank for efficient, exam-focused revision.

Why ophthalmology matters in MRCP Part 1

Ophthalmology questions in MRCP Part 1 are usually conceptual and pattern-based, not detail-heavy. Examiners favour contrasts—painful vs painless red eye, optic nerve vs retinal disease, acute vs chronic vision loss. Candidates who revise these differences consistently outperform those who memorise isolated facts.

This article supports the main MRCP Part 1 overview (https://crackmedicine.com/mrcp-part-1/) and is designed as a rapid, high-yield revision resource for the weeks leading up to the exam.

Scope: what this article covers

You will revise ophthalmology through five core subtopics, each framed around exam-relevant contrasts:

1. Acute vs chronic vision loss

2. Red eye differentials

3. Optic nerve vs retinal disease

4. Glaucoma patterns

5. Neuro-ophthalmology essentials

Together, these account for the vast majority of ophthalmology questions in MRCP Part 1.

Ophthalmology 50 facts for MRCP Part 1 (high-yield differences)

A. Acute vs chronic vision loss (Facts 1–10)

1. Sudden, painless monocular vision loss → retinal artery or vein occlusion.

2. Sudden, painful loss → acute angle-closure glaucoma or uveitis.

3. Transient monocular blindness (amaurosis fugax) → embolic disease; carotid pathology.

4. Central vision loss → macular or optic nerve disease.

5. Peripheral vision loss first → glaucoma or retinitis pigmentosa.

6. Curtain-like visual loss → retinal detachment.

7. Altitudinal field defect → anterior ischaemic optic neuropathy.

8. Early colour vision loss → optic nerve disease.

9. Relative afferent pupillary defect (RAPD) → optic nerve or severe retinal disease.

10. Bilateral acute visual loss → consider intracranial, toxic, or metabolic causes.

B. Red eye: painful vs painless (Facts 11–20)

11. Pain + photophobia → anterior uveitis.

12. Severe pain + headache + nausea → acute angle-closure glaucoma.

13. Painless red eye → conjunctivitis or subconjunctival haemorrhage.

14. Purulent discharge → bacterial conjunctivitis.

15. Itching + watery discharge → allergic conjunctivitis.

16. Ciliary flush → deeper ocular inflammation.

17. Corneal fluorescein staining → abrasion or keratitis.

18. Contact lens wearer with pain → assume keratitis until proven otherwise.

19. Normal visual acuity → conjunctivitis more likely.

20. Reduced vision with red eye → serious pathology until excluded.

C. Optic nerve vs retinal disease (Facts 21–30)

21. Optic neuritis → pain on eye movement, colour desaturation.

22. Papilloedema → bilateral disc swelling with preserved early vision.

23. Papillitis → disc swelling with visual loss.

24. Retinal disease → haemorrhages/exudates on fundoscopy.

25. Optic nerve disease → RAPD common.

26. Macular disease → central scotoma.

27. Peripheral retinal disease → tunnel vision.

28. Cherry-red spot → central retinal artery occlusion.

29. “Blood and thunder” fundus → central retinal vein occlusion.

30. Optic disc pallor → chronic optic nerve damage.

D. Glaucoma patterns (Facts 31–40)

31. Primary open-angle glaucoma → chronic, asymptomatic early.

32. Angle-closure glaucoma → acute, painful emergency.

33. Raised intraocular pressure → risk factor, not diagnostic alone.

34. Optic disc cupping → hallmark of glaucomatous damage.

35. Peripheral field loss precedes central loss in glaucoma.

36. Normal-tension glaucoma still causes optic nerve damage.

37. Systemic or topical steroids can precipitate glaucoma.

38. African ancestry → higher risk of open-angle glaucoma.

39. Hypermetropia → risk factor for angle-closure.

40. Family history → major risk factor.

E. Neuro-ophthalmology essentials (Facts 41–50)

41. Bitemporal hemianopia → optic chiasm compression.

42. Homonymous hemianopia → post-chiasmal lesion.

43. Ptosis + dilated pupil → compressive third nerve palsy.

44. Ptosis with normal pupil → consider myasthenia gravis.

45. Internuclear ophthalmoplegia → medial longitudinal fasciculus lesion.

46. Sixth nerve palsy → failure of eye abduction.

47. Raised intracranial pressure commonly affects the sixth nerve first.

48. Horner syndrome → ptosis, miosis, anhidrosis.

49. Visual neglect → cortical, not ocular pathology.

50. Pain on eye movement → inflammatory optic nerve disease.

High-yield comparison table

Feature	Optic neuritis	Papilloedema
Visual acuity	Reduced early	Preserved early
Pain	With eye movement	Absent
Laterality	Often unilateral	Bilateral
Underlying cause	Inflammatory/demyelinating	Raised intracranial pressure

Mini-MCQ (exam style)

A 30-year-old woman presents with subacute unilateral visual loss, pain on eye movement, and reduced colour vision. Fundoscopy is normal. What is the most likely diagnosis?

Answer: Optic neuritis. Explanation: Pain on eye movement and colour desaturation strongly indicate optic nerve inflammation. A normal disc does not exclude optic neuritis (retrobulbar neuritis).

Practise similar questions in the Crack Medicine MRCP question bank: https://crackmedicine.com/qbank/

Common pitfalls (five examiner favourites)

• Assuming all red eyes are conjunctivitis

• Missing optic nerve disease when fundoscopy appears normal

• Confusing papilloedema with papillitis

• Over-relying on intraocular pressure alone to diagnose glaucoma

• Ignoring colour vision testing in visual complaints

Practical study-tip checklist

• Revise differences, not isolated facts

• Link symptoms to anatomy (retina vs optic nerve vs cortex)

• Use short, focused sessions before full mock tests

• Review errors immediately after MCQs

• Reinforce weak areas with concise video lectures

Useful revision hubs:

• MRCP Part 1 hub: https://crackmedicine.com/mrcp-part-1/

• Mock exams: https://crackmedicine.com/mock-tests/

• Lectures: https://crackmedicine.com/lectures/

FAQs

Is ophthalmology heavily tested in MRCP Part 1?

No, but it is highly predictable. A small number of recurring concepts appear frequently.

What is the most common ophthalmology trap?

Misdiagnosing serious red eye (uveitis or glaucoma) as simple conjunctivitis.

Do I need detailed ophthalmic pharmacology?

No. MRCP Part 1 focuses more on diagnosis than treatment detail.

How should I revise ophthalmology quickly?

Focus on contrasts, practise MCQs, and revise mistakes rather than rereading textbooks.

Ready to start?

Use this article as a rapid revision aid, then consolidate with the MRCP Part 1 overview and attempt targeted questions in the question bank. For exam-day readiness, complete at least one full mock test.

Sources

• MRCP(UK) Examination Blueprint: https://www.mrcpuk.org

• Kumar & Clark’s Clinical Medicine, 10th edition

• Oxford Handbook of Ophthalmology, Oxford University Press