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The Silicone Hydrogels website is partially supported through an educational grant from CIBA VISION

 
In The Practice | Previous Articles
November 2007

 

The Use of O2 OPTIX Custom™ in a Case of Paediatric Aphakia

 

Deborah Jones, BSc FCOptom DipCLP FAAO

Debbie Jones is currently the Clinic Director and Head of Paediatrics & Special Needs in the School of Optometry at the University of Waterloo, Ontario, Canada. Debbie graduated in Optometry from City University in London, UK. She is a past Clinical Tutor in binocular vision and contact lenses at the Institute of Optometry in London, UK and a former Clinical Research Co-ordinator for Bausch & Lomb in the UK.
Lyndon Jones, PhD FCOptom DipCLP DipOrth FAAO (DipCL) FIACLE

Lyndon Jones is currently Professor at the School of Optometry, and the Departments of Physics, Biology, Chemistry & Chemical Engineering (cross-appointed), and Associate Director of the Centre for Contact Lens Research at the University of Waterloo in Ontario, Canada. He graduated in Optometry from the University of Wales, UK in 1985 and gained his PhD from the Biomaterials Research Unit at Aston University, UK in 1998. He is a Fellow and Diplomate of the American Academy of Optometry, has authored over 200 papers and conference abstracts, one text-book and given over 200 invited lectures at conferences worldwide.

 


When practitioners are faced with the challenge of fitting the unilateral pediatric aphake with a contact lens they have previously had to base their fitting strategy on the contact lens parameters available from the manufacturer. The introduction of custom made silicone hydrogel lenses has resulted in clinicians being able to fit the patient with the most appropriate CL parameters.

Table 1: CIBA Vision Silicone Hydrogel Lenses
Product Details
O2OPTIX™
NIGHT & DAY®
O2OPTIX Custom™
Material
lotrafilcon B
lotrafilcon A
sifilcon A
Water Content
33%
24%
32%
Dk & Dk/t @
-3.00D
110 & 138
140 & 175
82 & 117
Surface Treatment
permanent plasma
surface treatment
permanent plasma
surface treatment
permanent plasma
surface treatment
Modulus
1.0 MPa
1.2 MPa
1.1 MPa
Handling Tint
Light blue
None
Light green
Wearing Schedule
DW and EW up to 6N
DW and CW up to 30N
DW
Replacement Schedule
2 Weekly
Monthly
Quarterly
Packaging
6 pack
6 pack
1 & 4 pack
Design
Bi-Aspheric
Bi-Aspheric
Bi-Aspheric
Diameters
14.2
13.8
13.2 / 14.0 / 14.8
Base Curves
8.6
8.4, 8.6
7.4 – 9.2
Sphere Powers
 
+6.00 D to -10.00D
+6.00 D to -10.00D
+20.00 D to -20.00D
Center Thickness
0.08 @ -3.00D
0.08 @ -3.00D
0.07 @ -3.00D
Manufacturing Process
Mold Cast
Mold Cast
Lathe Cut

Table 2: O2 OPTIX Custom™ Parameters

Diameter

Base Curves

13.2
7.4, 7.7, 8.0, 8.3
14.0
7.8, 8.1, 8.4, 8.7, 9.0
14.8
8.0, 8.3, 8.6, 8.9, 9.2

A 7 year old unilateral aphake had been unsuccessfully fit with RGP lenses. He was refit with B&L Silsoft lenses. At the age of 5 the optimal lens parameters required for fit and acuity were outside of the available range. He needed the dimensions of an adult aphakic lens with the prescription of pediatric aphakic lens. Compromising the fit resulted in poor comfort and compromising the prescription resulted in poor acuity. An O2 Optix custom- made silicone hydrogel lens was fit in April 2007. The lens ordered was 8.7:14.00 +21.00D. On collection the patient reported superior comfort to other lenses he had worn.  Visual acuity was equivalent to the best corrected spectacle acuity (previously not achieved with a contact lens). The lens appeared to mask 1.00D of corneal astigmatism.

Fig 1: Master NB
Fig 2: Deposited silicone elastomer lens
Fig 3a: Master NB in
spectacles due to contact
lens intolerance
Fig 3b: Master NB wearing
O2 Optix Custom contact
lens
Fig 4: Fit of O2 Optix Custom lens on NB, showing excellent centration. Lenticulation due to high BVP is clearly seen

This case illustrates how a custom made SiHy lens can be used for aphakic patients who fall outside of the parameters of conventional aphakic lens designs.

Case Report

Age 6 months

  •  Master NB (Fig 1) was diagnosed with unilateral congenital cataract (OD).
  •  Surgery followed within one month.
  •  Post operatively fitted with a silicone elastomer contact lens (B&L Silsoft).

Age 12 months

  •  Due to heavy deposition, NB was refit with an RGP lens.
  •  Intensive patching regime of 2/3 waking hours.
  •  RGP wear was unsuccessful, with frequent lens loss and poor comfort.

Age 4 years

  •  NB refit once again with the B&L Silsoft lens.
  •  The Silsoft lens proved unsuccessful again due to:
    •  heavy deposits (Fig 2)
    •  poor comfort
    •  poor visual acuity compared to spectacles
    •  limited parameter range
  •  Reverted to mainly spectacles (Fig 3a)

Age 7 years

  •  April 2007 refit with CIBA Vision O2OPTIX Custom™ silicone hydrogel lens
    •  8.70:14.00 + 20.00D
  •  Collection - May 2007
    •  Acuity 6/15 - equivalent to spectacle acuity
      •  1.00 D corneal astigmatism masked by the lens
    •  Fit - well centered, moving well
    •  Comfort - good
  •  Progress check - June 2007
      •  Acuity 6/15
      •  Comfort – excellent (Fig 3b)
      •  Fit – excellent centration and movement (Fig 4)
      •  Wearing daily for 12-13 hours
  1. Moore BD: Pediatric aphakic contact lens wear: rates of successful wear. J Pediatr Ophthalmol Strabismus 1993; 30;4: 253-8.
  2. Ma JJ, Morad Y, Mau E, Brent HP, Barclay R, Levin AV: Contact lenses for the treatment of pediatric cataracts. Ophthalmology 2003; 110;2: 299-305.
  3. Polse KA, Sarver MD, Harris MG: Corneal effects of high plus hydrogel lenses. Am J Optom Physiol Opt 1978; 55;4: 234-7.
  4. Polse KA, Holden BA, Sweeney D: Corneal edema accompanying aphakic extended lens wear. Arch Ophthalmol 1983; 101;7: 1038-41.
  5. Rae ST, Huff JW: Studies on initiation of silicone elastomer lens adhesion in vitro: binding before the indentation ring. CLAO J 1991; 17;3: 181 - 186.
  6. Huth S, Wagner H: Identification and removal of deposits on polydimethylsiloxane silicone elastomer lenses. Int Contact Lens Clin 1981; 8;7/8: 19-26.

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