Electroretinography (ERG)

1. ERG measures the function of:
A. Optic nerve
B. Retina ✅
C. Visual cortex
D. Lens
Exp: ERG records retinal electrical activity in response to light.

2. The main waveforms of ERG are:
A. a-wave, b-wave ✅
B. P100 wave
C. Alpha, beta waves
D. Hippus wave
Exp: a-wave (photoreceptors), b-wave (Müller & bipolar cells).

3. The a-wave of ERG represents activity of:
A. Photoreceptors ✅
B. Bipolar cells
C. Ganglion cells
D. RPE
Exp: a-wave = negative deflection from photoreceptors.

4. The b-wave of ERG originates from:
A. Müller & bipolar cells ✅
B. Photoreceptors
C. Ganglion cells
D. Optic nerve
Exp: Positive deflection, inner retina response.

5. c-wave of ERG originates from:
A. RPE ✅
B. Ganglion cells
C. Müller cells
D. Lens
Exp: Generated by RPE and Müller cells.

6. Normal ERG is extinguished in:
A. Retinitis pigmentosa ✅
B. Optic neuritis
C. Cataract
D. Glaucoma
Exp: Rod-cone degeneration → flat ERG.

7. ERG is normal in:
A. Optic nerve diseases ✅
B. Retinitis pigmentosa
C. Cone dystrophy
D. CSNB (congenital stationary night blindness)
Exp: ERG tests retina, not optic nerve.

8. Photopic ERG tests:
A. Cones ✅
B. Rods
C. Bipolar cells only
D. Optic nerve
Exp: Done in light → cone function.

9. Scotopic ERG tests:
A. Rods ✅
B. Cones
C. RPE
D. Optic nerve
Exp: Dark-adapted ERG → rod function.

10. ERG is useful in diagnosis of:
A. Retinitis pigmentosa ✅
B. Glaucoma
C. Optic neuritis
D. Cataract
Exp: Detects rod-cone dystrophy.

Electrooculography (EOG)

11. EOG records electrical activity of:
A. Retina
B. RPE ✅
C. Lens
D. Optic nerve
Exp: EOG measures potential between cornea and retina, mainly RPE function.

12. The normal Arden ratio (light/dark ratio) is:
A. >180%
B. >200%
C. >1.85 (185%) ✅
D. <1.0
Exp: Normal EOG = Arden ratio ≥185%.

13. Subnormal EOG is seen in:
A. Best’s disease ✅
B. Optic neuritis
C. Retinitis pigmentosa
D. Cataract
Exp: Best’s vitelliform macular dystrophy shows abnormal EOG.

14. In Best’s disease, ERG is:
A. Normal ✅
B. Absent
C. Extinguished
D. Reduced
Exp: ERG normal but EOG abnormal.

15. EOG light peak arises due to:
A. RPE function ✅
B. Müller cells
C. Photoreceptors
D. Ganglion cells
Exp: RPE activity increases corneoretinal potential in light.

16. EOG is normal in:
A. Optic nerve disease ✅
B. Best’s disease
C. Cone dystrophy
D. RPE dystrophy
Exp: RPE must be intact for normal response.

17. Arden ratio is reduced in:
A. Best’s disease ✅
B. Retinitis pigmentosa
C. Stargardt’s disease
D. All of the above ✅
Exp: Several RPE disorders show low Arden ratio.

18. Which is more sensitive for RPE dysfunction?
A. ERG
B. EOG ✅
C. VEP
D. OCT
Exp: EOG specifically assesses RPE integrity.

19. EOG is recorded in:
A. Darkness & light ✅
B. Only light
C. Only dark
D. With visual evoked stimulus
Exp: Compares dark trough and light peak.

20. Arden ratio compares:
A. Light peak to dark trough ✅
B. a-wave to b-wave
C. ERG to VEP
D. Cones to rods
Exp: Ratio used to quantify RPE activity.

Visual Evoked Potential (VEP)

21. VEP measures activity of:
A. Retina
B. Optic nerve → visual cortex ✅
C. RPE
D. Lens
Exp: Records cortical response to visual stimulus.

22. The most important VEP wave is:
A. a-wave
B. b-wave
C. P100 ✅
D. N1
Exp: P100 latency is most consistent and clinically useful.

23. Delayed P100 latency in VEP is seen in:
A. Optic neuritis ✅
B. Retinitis pigmentosa
C. Best’s disease
D. Cataract
Exp: Demyelination delays conduction → optic neuritis.

24. VEP is abnormal in:
A. Optic nerve disease ✅
B. Cortical blindness ✅
C. Both A & B ✅
D. Retinitis pigmentosa
Exp: VEP evaluates post-retinal visual pathway.

25. Normal VEP with poor vision suggests:
A. Non-organic visual loss ✅
B. Optic neuritis
C. Retinitis pigmentosa
D. RPE dysfunction
Exp: Functional vision loss shows normal VEP.

26. Flash VEP is used in:
A. Uncooperative patients & infants ✅
B. Adults with normal vision
C. Only macular disorders
D. ERG abnormalities
Exp: Flash VEP doesn’t require fixation.

27. Pattern VEP assesses:
A. Macular & optic nerve function ✅
B. Peripheral retina
C. Lens
D. Vitreous
Exp: Requires fixation, central visual function tested.

28. Absent VEP with extinguished ERG suggests:
A. Retinal disease ✅
B. Optic nerve disease
C. Cortical disease
D. Refractive error
Exp: Both abnormal → retinal origin.

29. Normal ERG but abnormal VEP suggests:
A. Optic nerve disease ✅
B. Retinal disease
C. RPE disease
D. Vitreous degeneration
Exp: Retinal function intact, conduction defect post-retinal.

30. Normal VEP with abnormal ERG suggests:
A. Retinal disease ✅
B. Optic nerve disease
C. Cortical blindness
D. Functional loss
Exp: Retinal dysfunction, optic nerve & cortex intact.

Clinical Correlations

31. ERG extinguished but VEP normal in:
A. Retinitis pigmentosa ✅
B. Optic neuritis
C. Cortical blindness
D. Functional vision loss
Exp: RP affects photoreceptors, optic nerve intact.

32. ERG normal but VEP abnormal in:
A. Optic neuritis ✅
B. RP
C. Best’s disease
D. Cataract
Exp: Post-retinal conduction defect.

33. Both ERG & VEP abnormal in:
A. Leber’s congenital amaurosis ✅
B. Optic neuritis
C. Cortical blindness
D. Best’s disease
Exp: Diffuse retinal + optic nerve involvement.

34. EOG abnormal with normal ERG in:
A. Best’s disease ✅
B. Retinitis pigmentosa
C. Stargardt’s
D. Glaucoma
Exp: Classic finding.

35. VEP is normal in:
A. Functional visual loss ✅
B. Optic neuritis
C. Cortical blindness
D. Amblyopia
Exp: Confirms malingering.

36. Delayed VEP P100 latency suggests:
A. Demyelination (e.g., MS, optic neuritis) ✅
B. Retinal dystrophy
C. Cataract
D. Corneal opacity
Exp: Slowed conduction along optic nerve.

37. ERG is useful in differentiating:
A. Retinal vs optic nerve disease ✅
B. Lens vs vitreous disease
C. RPE vs cornea disease
D. Glaucoma vs cataract
Exp: ERG normal in optic nerve disease.

38. Abnormal Arden ratio indicates:
A. RPE dysfunction ✅
B. Optic nerve lesion
C. Retinal ganglion cell loss
D. Vitreous opacity
Exp: Specific for RPE.

39. EOG & ERG both normal, but VEP abnormal suggests:
A. Optic nerve disease ✅
B. Retinitis pigmentosa
C. Best’s disease
D. Vitamin A deficiency
Exp: Confirms conduction defect post-retinal.

40. Which test best localizes optic nerve conduction defects?
A. ERG
B. EOG
C. VEP ✅
D. OCT
Exp: VEP specifically tests optic nerve → cortex.