ABO Cheat Sheet 2026

The 30 highest-yield ABO facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Which of the following is the most common benign intraocular tumor in adults? → Choroidal nevus
2. What is the primary physiological cause of presbyopia? → Decreased elasticity and hardening of the crystalline lens.
3. Which condition is characterized by transient visual loss in one eye described as a 'curtain' descending? → Amaurosis fugax
4. What is the first-line treatment approach for bilateral retinoblastoma in modern practice? → Systemic chemoreduction followed by focal consolidation
5. What is the most common form of intraocular malignancy overall, including secondary tumors? → Choroidal metastases
6. A patient's refraction is -4.50 +1.00 x 090. To correct this refractive error, what type of lens is required? → A sphero-cylindrical concave lens
7. Which muscle is primarily involved in esotropia correction surgery? → Medial rectus
8. Snell's Law (n1 * sin(θ1) = n2 * sin(θ2)) is a fundamental principle in optics that describes: → The refraction of light as it passes between two different media.
9. Which chromosomal abnormality in uveal melanoma is most strongly associated with metastatic risk? → Monosomy 3
10. Which of the following classes of topical glaucoma medications primarily works by increasing the uveoscleral outflow of aqueous humor? → Prostaglandin analogs
11. Which of the following is characteristic of Duane Retraction Syndrome? → Globe retraction
12. Which of the following statements best describes the anatomical and physiological state of the lens nucleus in an elderly patient? → It has the highest concentration of insoluble proteins and is dehydrated.
13. Which test is best to evaluate binocularity in young children? → Worth 4-dot test
14. Which cranial nerve palsy most commonly causes vertical diplopia? → Trochlear nerve (CN IV)
15. Which condition presents with a white pupillary reflex in a child? → Retinoblastoma
16. What is the primary mechanism by which phacoemulsification removes the crystalline lens? → High-frequency ultrasonic vibration
17. Which condition presents with sudden, painful proptosis and ophthalmoplegia? → Orbital cellulitis
18. Which of the following cycloplegic/mydriatic agents has the longest duration of action, often lasting for one to two weeks? → Atropine
19. Conjunctival melanoma most frequently arises from which precursor lesion? → Primary acquired melanosis (PAM) with atypia
20. What is the most common primary intraocular malignancy in adults? → Uveal melanoma
21. During subjective refraction to refine astigmatism, a Jackson Cross Cylinder (JCC) is used. What is the primary function of this instrument? → To refine the cylinder axis and power.
22. Retinoblastoma results from biallelic inactivation of which tumor suppressor gene? → RB1
23. Which genetic mutation is most commonly associated with uveal melanoma? → GNAQ/GNA11
24. What is the most common cause of a relative afferent pupillary defect (RAPD)? → Optic neuritis
25. What is the most appropriate management for a chalazion? → Warm compresses
26. Which of the following optical principles correctly describes the correction for hyperopia? → A converging (convex) lens is used to move the focal point forward onto the retina.
27. Which test is most useful for evaluating posterior uveitis? → Fluorescein angiography
28. Orbital rhabdomyosarcoma in children most commonly presents at which age range? → 5-10 years
29. Which of the following is a hallmark sign of anterior uveitis? → Cell and flare
30. A 50-year-old outdoor worker presents with a fleshy, triangular growth extending from the nasal conjunctiva onto the cornea. What is the most likely diagnosis? → Pterygium