Case Study – Keratoconus and High Myopia

History and Symptoms

  • Mrs S, a 41 year old nurse
  • RGP contact lens wearer
  • Worn glasses for myopia since childhood
  • Diagnosed with keratoconus in her left eye only in 1997
  • Interested in halting the progression of keratoconus – wants to avoid a corneal transplant

Initial Examination

UCVA Sphere Cyl Axis BCVA Near VA
Right <6/120 -16.00 -0.50 130 6/7.5 N5
Left <6/120 -15.00 -2.00 100 6/12 N5

 

Right Left
512 Pachymetry (µm) 500
5.6 Colvard Pupil (mm) 5.6
12 Goldmann Contact Tonometry (mmHg) 12
42.80 @ 93, 42.30 @ 3 Orbscan Keratometry (D) 45.50 @ 28, 42.90 @ 118
3.19 ACD (mm) 3.08
  • —  Anterior segment examination:

– Right Eye: Normal

– Left Eye: Keratoconus – Vogt’s striae visible

  • —  Bilateral posterior sub-capsular congenitial cataract
  • —  Fundus dilated Volk examination – typically myopic appearance however unremarkable.

Treatment Plan

Mrs S prescription is too high for laser treatment.

Keratoconus is also an absolute contra indication for laser treatment.

A Clear Lens Exchange could be considered however due to the increased risk of retinal detachment with patients ’under 50 years of age, an Implantable Contact Lens was advised with collagen cross linking treatment first in the LE to address the keratoconus.

Results

4 months after Left Eye Collagen Cross Linking

UCVA Sphere Cyl Axis BCVA
Right
Left <6/120 -14.00 -2.00 100 6/10

Pent1 Pent2

Right eye and left eye Pentacam taken 15/11/2012

16 months after Collagen Cross Linking and 3 months after bilateral Toric ICL

UCVA Sphere Cyl Axis BCVA
Right 6/7.5 Plano 6/7.5
Left 6/7.5 Plano 6/7.5

 

Mrs S was delighted with her vision and showed a marked improvement in best corrected visual acuity in her left eye.

Points to remember:

  • Collagen cross linking is a safe and effective treatment to halt keratoconus
  • High, complex prescriptions can be treated safely providing accurate ocular measurements are taken and patients are counselled carefully.
  • Multiple stage treatments are often required when developing a treatment plan for complex prescriptions

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