Topography-Guided Refractive Astigmatism Outcomes: Predictions Comparing Three Different Programming Methods

Figures & data

Figure 1 Treatment planning page for the WaveLight Contoura® Vision laser.

Table 1 Treatment Method Actually Used at Each Site

Site	Eyes	Method
1	10	LYRA^a
2	14	LYRA
3	6	LYRA
4	9	MR^b
5	8	LYRA
6	5	MR

Notes: ^aLayered Yolked Reduction of Astigmatism.⁴ bManifest refraction.

Table 2 Refractive Data Summary

	Mean	SD	Minimum	Maximum	p
Age	32.73	8.01	19	50
Preop CDVA^a (logMAR)	−0.08	0.06	−0.125	0.000
High	−0.08	0.06	−0.125	0.000	0.35
Low	−0.09	0.06	−0.125	0.000
Preop MR Sphere (D)	−3.64	1.78	−8.000	−0.500
High	−3.54	1.67	−6.750	−0.500	0.59
Low	−3.82	2.00	−8.000	−1.000
Preop MR Cylinder (D)	−0.89	0.56	−2.750	0.000
High	−0.95	0.64	−2.750	0.000	0.38
Low	−0.80	0.40	−1.750	0.000
Treatment Sphere (D)	−3.62	1.66	−7.550	−0.600
High	−3.56	1.56	−6.500	−0.870	0.72
Low	−3.73	1.87	−7.550	−0.600
Treatment Cylinder (D)	−1.01	0.53	−2.430	0.000
High	−1.06	0.52	−2.430	−0.400	0.38
Low	−0.93	0.56	−2.010	0.000
Postop UCDVA^b(logMAR)	−0.07	0.09	−0.300	0.100
Postop CDVA (logMAR)	−0.11	0.07	−0.300	0.000

Notes: ^aCorrected distance visual acuity. ^bUncorrected distance visual acuity.

Table 3 Difference in Refractive and Topographic Astigmatism Angle and Magnitude

Difference in Magnitude (D)	Difference in Orientation (Degrees)
	≤10	11 to 20	21 to 40	41 to 60	61 to 80	Total
≤0.50	1^a	5	4	3	1	14
0.51 < and ≤ 1.00	15	5	7	1	1	29
1.01 < and ≤ 1.50	6	1				7
1.51 < and ≤ 2.00	1		1			2

Note: ^aNumber of eyes.

Figure 2 Cumulative uncorrected visual acuities at 3 months.

Figure 3 Change in corrected distance visual acuity from preoperative exam to the 3-month postoperative exam.

Table 4 Centroids and Error Magnitude for Expected or Actual Cylinder Error by Method

Method	Group	X Coordinate	Y Coordinate	Magnitude (D)	Mean Error (D)
Manifest	High	−0.48 [0.47]^a	0.15 [0.28]	0.51	0.70 [0.46]
	Low	−0.17 [0.25]	−0.07 [0.15]	0.18	0.33 [0.23]
	All	−0.43 [0.47]	0.11 [0.28]	0.44	0.56 [0.42]
Topo	High	0.49 [0.37]	0.03 [0.31]	0.49	0.47 [0.35]
	Low	0.36 [0.33]	−0.08 [0.20]	0.37	0.48 [0.31]
	All	0.37 [0.36]	0.02 [0.28]	0.37	0.47 [0.33]
Phorcides	High	−0.17 [0.34]	0.10 [0.33]	0.19	0.48 [0.28]
	Low	−0.01 [0.28]	−0.08 [0.17]	0.08	0.26 [0.20]
	All	−0.15 [0.36]	0.06 [0.28]	0.16	0.39 [0.28]

Note: ^aValue[SD].

Table 5 Magnitude of Actual and Calculated Error Vectors by Method

Method	Magnitude of Error Vectors (D)
	≤0.25	≤0.50	≤0.75	≤1.00	>1.00
Manifest	16^a	29	36	44	8
Topo	17	30	43	50	2
Phorcides	19	36	45	50	2

Notes: ^aNumber of eyes.

Figure 4 Error vectors: difference between calculated Manifest and Best outcomes. Ellipses are the centroid ± SD for the low (

) and high (- - -) groups.

Figure 5 Error vectors: difference between Topo and Best outcomes. Ellipses are the centroid ± SD for the low (

) and high (- - -) groups.

Figure 6 Error vectors: difference between Phorcides and Best outcomes. Ellipses are the centroid ± SD for the low (

) and high (- - -) groups.

Motwani M. The use of WaveLight(R) Contoura to create a uniform cornea: the LYRA protocol. Part 1: the effect of higher-order corneal aberrations on refractive astigmatism. Clin Ophthalmol. 2017;11:897–905. doi:10.2147/OPTH.S133839

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