Astigmatism (in diop)
40–50yo
50–60yo
60–70yo
70–80yo
80 + yo
For with-the-rule and oblique astigmatism
1.00–1.50
60°(1)
50°(1)
50°(1)
40°(1)
30°(1)
1.50–2.00
70°(1)
70°(1)
70°(1)
60°(1)
60°(1)
2.00–2.50
60°(2)
60°(2)
60°(2)
70°(1)
70°(1)
2.50–3.00
70°(2)
70°(2)
70°(2)
60°(2)
60°(2)
3.00–4.00
80°(2)
80°(2)
80°(2)
70°(2)
70°(2)
For against-the-rule astigmatism
1.00–1.50
60°(1)
50°(1)
40°(1)
40°(1)
30°(1)
1.50–2.00
70°(1)
60°(1)
60°(1)
60°(1)
40°(1)
2.00–2.50
60°(2)
80°(1)
80°(1)
70°(1)
60°(1)
2.50–3.00
70°(2)
70°(2)
70°(2)
60°(2)
60°(2)
3.00–4.00
80°(2)
80°(2)
80°(2)
70°(2)
70°(2)
For many years, I always performed paired LRIs, a carry-over from 6 mm OZ astigmatic keratotomies during the radial keratotomy era. I started working with single LRIs after examining a 15-year-old who had suffered a partial peripheral corneal laceration which corrected his 2-D corneal astigmatism that was still present in his fellow eye. I found that since we make the LRI so far in the corneal periphery, single incisions do not create significant irregular astigmatism.