OPTOMETRY

1. OPTOM ASKAR.PK

2. Typically include:
Patient’s name, age, gender &
occupation
power of the lenses
any prism
The pupillary distance
Expiration date
The prescriber's signature.

3. 1. Prescription
 −1.00 /+0.25 x 180 :
horizontal power of −1.00 D
vertical power of −0.75 D.
Only ophthalmologists write prescriptions in +
cylinder.

4.  An optometrist would write a prescription in (minus) cylinder.
 All spectacle and contact lenses would be made in minus cylinder.
Therefore, the above prescription would be
written as −0.75 −0.25 × 90.

6. 2. Interpupillary distance

7. Measurement:
1. Ruler
2. pupilometer

8. Additional points to write in
prescription

9. Points to remember
 Prefer is given to prescription in minus cylinder form unless vision is
improves significantly with plus cylinder
 If axis of cyl. component is not vertical & horizontal, it is better to under
correct cylinder power.
 Prescription should be written clearly with correct sign & power

10. Some examples

12. Knapp’s Law and Axial Ametropia
According to Knapp’s law, “When a correcting lens i
s
so placed before the eye that its second principal
plane coincides with the anterior focal point of an
axially ametropic eye, the size of the retinal image
will be the same as though the eye were emmetropic.”
 (It should be noted that for Knapp’s law to be
fulfilled, the ametropia must be purely axial, and
there must be no anatomic Aniseikonia present.)

17. Abbreviation
 DV - distance vision.
 NV - near vision
 OD -oculus dexter
 OS -oculus sinister
 OU- oculi uterque
 United Kingdom, RE (right eye), LE (left eye),
and BE (both eyes) are used.
 Sometimes, just right and left are used.


18. Abbreviation
 SPH, CYL, and AXIS are values for describing the power of the lens using plus
cylinder or minus cylinder notation.
 ADD - Near Addition.
 Prism and Base Prism
 PL -plano or plain (meaning no prescription)
 PD or IPD Pupillary Distance or Interpupillary Distance.
 BVD Back vertex distance

19. TRIAL SET

32.  The JCC comes in +0.25/-0.25 or +0.50/-0.50
formats. The commonly used JCCs are +0.25/ -
0.50 (or -0.25/ +0.50) and +0.50/ -1.0 (or -
0.50/ +1.0).

36. 1-1.2 mm
mm