Vision Assessment: Examination Essentials
NEET PG / Board Examination High-Yield
1. Distance Visual Acuity (DVA)
- Snellen Chart: Standard method. Tested at 6 meters (or 20 feet).
- Illiterate E / Landolt C Chart: Used for children or illiterate patients.
- LogMAR Chart: Preferred in research for more accurate, linear scaling of visual acuity.
2. Assessment for Subnormal Vision
When a patient cannot read the largest letter (6/60), follow this standard sequence:
| Step | Assessment |
|---|---|
| Counting Fingers (CF) | Assess distance (in meters) where fingers are counted. |
| Hand Movements (HM) | Assess the distance where hand motion is perceived. |
| Perception of Light (PL) | PL+ (Light perceived) vs. PL- (No Light Perception / NLP). |
| Projection of Rays (PR) | Test light projection in 4 quadrants to evaluate retinal function. |
3. Near Vision Assessment
- Jaeger Chart: The most common clinical standard for near vision (J1 to J16).
- Roman Chart / N-notation: (e.g., N6, N8, N10). N6 is equivalent to 6/6 distance vision.
4. NEET PG High-Yield Pearls
- Pinhole Test: Used to distinguish refractive error from pathological vision loss. If acuity improves with a pinhole, the cause is a refractive error.
- 6/60 Vision: If a patient can only see at 1 meter, the vision is expressed as 1/60.
- Light Projection: Essential before cataract surgery to assess for underlying retinal detachment or optic nerve disease.