Global Insight

by Laura Batres, M.Sc. Optometry and Vision

Orthokeratology (ortho-k) lenses are currently limited to the correction of myopia and low astigmatism. New designs of toric orthokeratology lens and toric optic zone lenses have been shown to be effective and safe in patients with myopia combined with astigmatism who were previously not satisfied with the corrected visual acuity.

Woman, 50-year-old, was interested in ortho-k because she could not tolerate her soft contact lenses.

Ocular surface: Keratoconjunctivitis sicca in both eyes.

Break up Time: < 5 seconds in both eyes.

Patient was recommended not to wear her soft contacts for 4 weeks and to insert artificial tear with 0.2% hyaluronate 3 times a day.

Spectacle Rx

OD -5.25 -1.50 x 150 VA 1.2

OS -4.25 -2.00 x 175 VA 1.2

Keratometry

OD 7.61@ 166    7.39 @ 76

OS 7.59 @ 177   7.22 @ 87

Corneal Diameter

WTW 11.92 (R); 11.84 (L)

Toric Ortho-K Contact Lenses: ESA ORTHO-6 Toric. 

OD – Nk 7.60 F’v +0.50 TPwr -4.75 Tor -1.50 Diam 10.80

OS – Nk 7.60 F’v +0.50 TPwr -3.75 Tor -2.50 Diam 10.80

After 1 week of wear, the fluorescein pattern of the left lens revealed small excessive toricity in the vertical meridian, but it was decided not to change this parameter because of high visual acuity.

Visual Acuity

From the very beginning, the patient reported some blur in both eyes despite high visual acuity, but it was decided not to change the lens parameters as very often this blur disappears after 2 – 3 months of wear.

1m

OD -0.50 -0.25 x 180  1.2

OS -0.25 -0.75 x 180  1.2

4m

OD +0,00

OS +0.50 -0.50 x 150 1.2

8m

OD +0,00

OS  +0,00 -1.50 x 180 1.2

12m

OD +0.50 -0.50 x 35

OS +0.25 -1.25 x 15

R – Topography

L – Topography

Considering the patient’s continued reports of some blur in both eyes, after 1 year of wear, it was decided to change lens parameters by adding central toricity to correct residual astigmatism. The peripheral toricity of the left lens was also reduced by 0.5 D.

OD – Nk 7.60 F’V +1.25 Tpwr -5.00 Tor -1.50 Diam 10.80 BOZ -1.00 x 165

OS – Nk 7.60 F’V +0.75 Tpwr -3.50 Tor -2.00 Diam 10.80 BOZ -1.00 x 15

R – Topography

L – Topography

Visual Acuity with New Dual Toric Ortho-K Lenses

	BASELINE	16M	20M
R	<0,05	1,2	1,2
L	<0,05	1,1	1,2

Spectacle Rx

OD  +0.50 -0.50 x 50 1.2

OS +0.50 1.2

With dual toric ortho-k lenses, residual astigmatism has been minimized and the patient’s visual quality has been subjectively improved.

Conclusion

Ortho-k lenses fitted with peripheral toricity and back toric optical zone are a viable option in some cases with more demanding patients to help improve their visual quality. 

Thank you to Laura Batres for contributing to Global Insight.