1. Make your Grade! Primary Optometry Midterm is Tuesday November 11, 3:00 – 4:30 in this room. 3 cases to graph, 20 questions.

2. Accommodative demand (diopters) =________1___________ target distance (meters) Convergence demand (prism diopters) = 10 x PD(mm) = PD(cm) distance (cm) distance(M) PD = 60cm and convergence demand at near is 15 prism diopters.

3. Convergence (Meter Angles) = Accommodative demand (diopters) Convergence (prism diopters) = Meter Angles x PD(cm) Donder’s demand line represents perfect accommodation & vergence at every viewing distance; ‘ortho’ line.

4. At distance, perfect accommodation = 0D and perfect vergence = 0 regardless of the PD. At near, perfect accommodation = 1 / distance(M) and perfect vergence = 10 x Pd (mm) / distance (cm). Re-label upper vergence scale with new zero; draw new vertical.

6. The NRA can be limited by either PFV or accommodation. The PRA can be limited by either NFV or accommodation.

7. The calculated AC/A ratio = total change in vergence between distance and near / total change in accommodation Calculated AC/A = 27pd/ 2.5D = 10.8:1

8. The gradient AC/A = difference between near phoria measure and near phoria through +1.00D or –1.00D. Gradient AC/A = 23 ESO – 1 ESO / 2D = 22/2 = 11:1

9. Training or Orthoptics is done to increase fusional vergence and has the effect of shifting the sides of the zone to higher values. Training does not change the phoria.

10. BI Prism shifts the demand line to the left so that the value of the EXOphoria and the BI ranges are reduced and the BO ranges are increased by the value of the prism.

11. The phorometric values expected through added lens power are read from the appropriate accommodative demand off the appropriate vergence scale. Near through +0.75D

12. Sheard’s Criterion For EXOPHORES Reserve (BO to blur) must equal twice the demand (exophoria) to pass Sheard’s. If Sheard’s is not passed, then training, prism or lenses to meet Sheard’s is advised. Prism (BI) = 2/3 Demand - 1/3 Reserve Lens power (-) S = Prism / AC/A

14. Percival’s Criterion For ESOPHORES To pass Percival’s, ZERO must be in the middle one-third of the zone of clear, single, binocular vision. If Percivals’s is not passed, then prism or lenses to meet Percival’s is advised. Prism (BO) = 1/3 Greater - 2/3 Lesser Lens power (+) S = Prism / AC/A

15. Prism:

16. Lens: