Identical twins JD1 and JD2 started a course of orthokeratology with me some years ago.
Both had lenses fitted successfully, allowing them to have perfect vision during the waking hours and needing to wear their lenses only while sleeping to maintain the effect.
Research has shown that ortho-K has the added benefit of myopia control. This case describes how both had stable prescriptions after fitting but how one started to change as soon as she stopped wearing the lenses.
JD1 was fitted with BE orthokeratology lenses for her myopia. Her prescription was RE -2.50 -0.50×120 LE -2.50 -0.50×45. The parameters of her lens were RE 7.90/11.0 LE 7.80/11.0.
Topography plots (Figure 1) show she had a good central treatment zone with a central flattening of about 3.50 D. We ordered these lenses and organised a review for six months later.
Figure 1. Topography plots show twin JD1 had a good central treatment zone with a central flattening of about 3.50 D. Her twin sister’s (JD2) vision was still 6/6 in each eye two years after fitting, and almost identical topography.
She was lost to follow up and returned to the practice just over two years later. She had lapsed in the care of her lenses and for the past 12 months had not used them at all but had returned to her spectacles.
When we repeated her refraction we found her prescription had increased to RE 3.25 0.50×120 LE -3.50 -0.50×45. This represented an increase in the sphere power of 0.75 D in the left and 1.00 D in the right.
During these visits her twin sister (JD2) had accompanied her. I asked about her progress and she said she had stayed with the lenses and her vision was still fine. A review found her vision was still 6/6 in each eye and almost identical topography.
I concluded there was a very real and measurable effect of myopia control for these sisters with identical genetic backgrounds. The ortho-K lenses in JD2 seemed to have held back the progress of her myopia while her sister had deteriorated, presumably some time after she had ceased lens wear.
Her change in prescription meant we had to refit JD1 with new lenses. Because of the higher script we fitted her with GOV XMJ lenses with parameters of RE 45.75/10.4/-3.50 LE 45.75/10.4/-3.50.
Within four nights her vision had returned to 6/6 in each eye after lens removal and she was happy.
* ANZ Distributor, GOV Oceania orthokeratology contact lenses