Aphakia is the absence of the eye's crystalline lens. Without the lens, the eye is hyperopic and vision is blurred for both distance and near. There are several treatment options for aphakia including spectacles, contact lenses, intraocular lenses, and refractive corneal surgery. Spectacles are the most basic option but have several disadvantages like increased retinal image size, decreased field of view, and presence of ring scotomas. Other options aim to address these issues and improve vision.

1. APHAKIA
- REVATHY R

2. What is Aphakia?
• Aphakia – No lens
• Absence of crystalline lens from the eye
• Optically Aphakia means absence of lens from pupillary
area and it does not takes part in refraction

3. Normal Eye

4. Aphakic Eye

5. Optics
 Simply defined
 Total Ocular Refractive power = 60D
 Without lens = 60D-17D = 44D
 Eye become Hyperopic
 Needs Plus lenses to correct the focus

6. Causes
 Congenital
 Inherited disorders
 Trauma
 Surgery

7. Lens subluxation

8. Vision in Aphakia
 Blurred
 Both distance and Near
 Loss of Accommodation
 Loss of Binocular Vision

9. Treatment Options
 Spectacles
 Contact lens
 IOL(intraocular lens)
 Refractive corneal surgery

10. Spectacles
• Conventional
Option
• Convex lenses

11. Advantages of spectacles
Easy
Safe
Inexpensive

12. PROBLEMS OF GIVING SPECTACLES
 1. Increased retinal image size
 2. Decreased field of view
 3. Presence of ring scotoma
 4. Increased lens aberrations
 5. Motion of object in field of view
 6. Appearance of the wearer
 7. Increased ocular rotations
 8. Demand on convergence

13. Increased Retinal image Size
 Large size image
 33% Maginification
 1 cm = 1.36 cm
 Familiar object not only appear to be much larger , they also appear
to be much closer
 Over estimation of Visual Acuity due to increased image size
 Increased magnification weaker reading addition

14. INCREASED IMAGE SIZE

15. DECREASED FIELD OF VIEW WITH
MAGNIFICATION

16. RING SCOTOMA
Ring scotoma moves in opposite direction of the eye
movement ( roving eye scotoma )

17. JACK IN THE BOX PHENOMENA

18. PINCUSHION DISTORTION

19. INCREASED OCULAR ROTATION
 Angle of eye turning in
changing fixation from
one object point to
another increases in
comparison to
emmetropic.
 Due to prismatic effect

20. APPEARANCE OF THE WEARER

21. OTHER FACTORS TO BE CONSIDERED
 Loss of Accommodation
 Binocular Vision

23. DISPENSING ASPECTS
 Plastics
 High Index lenses
 Lenticular designs
 Aspheric designs
 Add limits
 Base In prisms/Decentration of Optic center
 Adjustable Nosepads
 Vertex distance – effective power