Edge profile of commercially available square-edge intraocular lenses

1
Edge profile of commercially available
square-edge intraocular lenses
Mayank A. Nanavaty1 David J. Spalton1 James
Boyce2 Anthony Brain2 John
Marshall2
1. St. Thomas Hospital, London 2. Kings
College, London
Financial interests None
2
Aim
To analyze the sharpness of the posterior optic
edge of intraocular lenses (IOLs) marketed with a
square-edge profile.
Methods

• Seventeen IOLs of different designs and
  material all marketed as square-edge IOLs
• 20 Diopter IOL of each selected
• IOLs examined with environmental scanning
  electron microscopy

3
FEI Quanta 200F field emission gun environmental
scanning electron microscope was used to examine
IOLs

• Parameters standardized for all IOLs
• 93.3 Pascal (0.7 torr),
• Specimen temperature of 20oC,
• Voltage of 15 KV
• Magnification x 500
• Average processing time 25 minutes

IOLs mounted using a simple microscope
Haptic excised
Some IOLs required cutting of the haptic and/or
optic to view edge
Posterior edge appears always on the left
4
Measurement of Radius of Curvature of Posterior
Optic Edge
Customised computer program measures the local
radius of curvature
L
L
P
P
R
r
R
r
Sharper optic edge Smaller r
See details in J Cataract Refract Surg, April
2008.
5
Hydrophobic Acrylic IOLs
9.9µ
9.3µ
8.5µ
Alcon AcrySof IQ
Alcon AcrySof Natural
Alcon AcrySof MA60AC
6
Hydrophobic Acrylic IOLs
8.3µ
19.9µ
Hoya AF-1(UY)
AMO Sensar AR40e
7
Hydrophilic Acrylic IOLs
15.9µ
14.3µ
B L MI60
B L Akreos
23.1µ
15.5µ
Rayner Superflex
Lenstec Tetraflex
8
Hydrophilic Acrylic IOLs
9.1µ
8.6µ
Human Optics 1CU
Human Optics MC611 MI-B
9
Silicone IOLs
7.6µ
8.3µ
Bausch Lomb Soflex SE
Bausch Lomb SofPort AO
10
Silicone IOLs
9.2µ
8.3µ
9.0µ
AMO Tecnis Z9000
AMO Clariflex
AMO Tecnis ZM9000
11
Summary
Radii of curvature (µ)
8.5
9.3
9.9
8.3
19.9
Alcon AcrySof SN60WF
Alcon AcrySof SN60AT
Alcon AcrySof MA60AC
AMO Sensar AR40e
Hoya AF-1(UY)
Hydrophobic Acrylic IOLs
Rayner C-flex (thinnest ridge)
Rayner C-flex (thickest ridge)
Rayner Superflex (thinnest ridge)
Rayner Superflex (thickest ridge)
Bausch Lomb Akreos
Bausch Lomb MI60
HumanOptics 1CU
HumanOptics MC 611 MI-B
Tetraflex
18.2
19.6
15.6
10.6
15.9
14.3
8.6
9.1
23.1
Hydrophilic Acrylic IOLs
Bausch Lomb Soflex
Bausch Lomb SofPort AO
AMO Clariflex
AMO Tecnis Z9000
AMO Tecnis ZM9000
8.3
7.6
8.3
9.2
9.0
Silicone IOLs
12
Conclusion

• Commercially marketed square edge IOLs differ
  in posterior edge sharpness.
• Most hydrophobic acrylic and silicone IOLs have
  sharper posterior optic square edges compared to
  most hydrophilic acrylic IOLs. This probably
  reflects difference in manufacturing techniques.
• The difference in the posterior optic edge
  profile may explain why some IOLs have relatively
  poor PCO performance and may explain why some IOL
  materials appear to have better PCO performance
  than others.