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GP lens eye Rounds

MYOPIA MANAGEMENT: Adult Corneoscleral Ortho-K Case

Daddi Fadel DOptom, FBCLA, FAAO, FSLS

History

  • 31-year-old male, Caucasian, with high myopia and moderate astigmatism, against-the-rule (ATR) in OD and oblique in OS.
  • He previously wore various soft toric CLs that did not provide comfort and stable vision.
  • The patient desired stable vision during wearing time.

Examination

  • Entering visual acuities:
    • OD: 20/400
    • OS: 20/200
  • Refraction:
    • OD: -6.50 -1.75 x 115, 20/16
    • OS: -5.50 -1.75 x 60, 20/16
  • Slit Lamp Examination:
Lids/Lashes Clean and Clear
Palpebral Conjunctiva No papillae
Cornea Clear and intact, no staining NaFl
Tear film TBUT 16 seconds

 

  • Corneal Topography (Figure 1):
OD OS
Keratometry 7.35 mm / 7.19 mm 7.35 mm / 7.18 mm
Corneal astig. ATR -1.04 x 110 Oblique -1.08 x 37
Eccentricity 0.37 / 0.43 0.45 / 0.32
HVID 11.50 mm 11.35 mm
Biometry 26.50 mm 26.45 mm
Residual Astigmatism -0.46 x 115 -0.42 x 60

Pupil diameter: Photopic 4.70 mm; mesopic 6.00 mm in both eyes
Dilated Fundus Examination: No holes, breaks, or tears OD, OS

Decision-Making Process

Considering costs, the patient’s request for stable vision, and his previous experience with soft contact lenses, ortho-K lenses were selected to correct his refractive error. However, considering the type of corneal astigmatism, corneoscleral ortho-k lenses were designed for better lens alignment and centration. The ortho-K lenses were applied to simply correct the refractive error without any purpose for myopia control. The patient was educated about the potential for increased glare and haloes during nighttime driving.

Fitting and Evaluation

  • Ortho-K lenses were designed empirically using a topography map and based on the Horizontal Visible Iris Diameter (HVID) and refractive target with a Jessen Factor of +0.75D. Lens diameter: 14.80 mm.
  • First dispense: The lenses were properly centered. The fluorescein pattern was optimal.
  • One-week follow-up: Well-centered treatment zone in both eyes. The surrounding red annulus was entirely in the pupil area.
    • ORx: OD -1.00 -0.50 x 115 20/32; OS -0.50 -0.50 x 60 20/22
  • The patient complained of poor vision, especially during the night.
  • The plan was to increase the back optic zone diameter to reduce high order aberrations (HOAs) and flatten the back optic zone radius for better correction of residual myopia.

Figure 2: Tangential difference map of the first pair of lenses showing the corneal topography changes

  • Second dispense: The lenses were properly centered. The fluorescein pattern was optimal.
  • One-week follow-up visit: Well-centered treatment zone in both eyes, with the surrounding red annulus partially within the pupil area. (Figure 3)
    • ORx: OD 0.25 -0.50 x 115 20/20; OS pl -0.50 x 60 20/20; OU 20/20
  • Slit lamp examination: Cornea was clear and intact; no staining with fluorescein application.
  • One-month follow-up visit: All findings remained consistent with the one-week follow-up. The patient was satisfied with the daytime quality of vision and eye comfort. He reported mild glare and halos while driving at night but did not feel that their visual acuity (VA) is negatively affected.
    Plan: Finalize the lens.

Figure 3: Tangential difference map of the second pair of lenses showing the corneal topography changes

Clinical Pearls

  • Listening to patients’ needs is essential to determine the best option to correct their refractive error.
  • Several designs are available for corneal, scleral, and ortho-K lenses. Considering innovative designs is crucial to better managing patients’ requests and expectations.
  • Corneoscleral ortho-K is an option to consider in adults for better lens centration.
  • Glare and halos may impact night driving in adults who wear ortho-K lenses; patients’ expectations should be set before lens application.
  • Proper lens centration and back optic zone diameter are essential to manage HOAs.
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