A novel nomogram for the treatment of astigmatism with femtosecond-laser arcuate incisions at the time of cataract surgery

Figures & data

Table 1 Modification of Donnenfeld nomogram

Axis orientation	Degrees of astigmatism	Percentage of Donnenfeld nomogram
With-the-rule	60–120	70
Against-the-rule	0–30 and 150–180	100
Oblique	31–59 and 121–149	80

Figure 1 Basic procedure: place incisions, (A) align suction ring, (B) set parameters, (C and D) confirm 3D depth with optical coherence tomography.

Table 2 Preoperative Kcyl, postoperative Kcyl, and postoperative RRA (in diopters)

Measures	WTR astigmatism (n=104) Mean ± SD (range)	ATR astigmatism (n=43) Mean ± SD (range)	OBL astigmatism (n=14) Mean ± SD (range)	All eyes (n=161) Mean ± SD (range)
Preoperative Kcyl	0.829±0.314 (0.5–2.0)	0.947±0.302 (0.5–1.75)	0.779±0.360 (0.5–1.9)	0.856±0.318 (0.5–2.0)
Postoperative Kcyl	0.664±0.397 (0.0–1.5)	0.573±0.486 (0.0–2.00)	0.526±0.303 (0.0–1.0)	0.626±0.417 (0.0–2.0)
Postoperative RRA	0.389±0.328 (0.0–1.25)	0.709±0.475 (0.0–1.75)	0.689±0.446 (0.0–2.25)	0.495±0.400 (0–1.5)
Mean Δ Kcyl	0.165±0.383 (-0.55–1.5)	0.374±0.536 (-0.85–1.5)	0.253±0.416 (-0.45–1.15)	0.230±0.436 (-0.85–1.5)
P-values of Δ Kcyl	<0.001	<0.001	0.02	<0.001

Note: Mean Δ Kcyl = preoperative Kcyl–postoperative Kcyl.

Abbreviations: Kcyl, keratometric corneal cylinder; RRA, residual refractive astigmatism; WTR, with-the-rule; ATR, against-the-rule; OBL, oblique.

Figure 2 Percentage of eyes with ≤0.5 diopters of keratometric cylinder preoperative and postoperative in eyes with against-the-rule, oblique, and with-the-rule astigmatism, and all astigmatic eyes combined.

Abbreviations: ATR, against-the-rule; OBL, oblique; WTR, with-the-rule.

Figure 3 Correction index vector plots, preoperative Kcyl and postoperative Kcyl.

Abbreviations: Kcyl, keratometric corneal cylinder; WTR, with-the-rule; ATR, against-the-rule; OBL, oblique.

Table 3 Distribution of overcorrected eyes after femtosecond-assisted arcuate incisions

Axis orientation	>150%		>125%		>100%
	Kcyl	RRA	Kcyl	RRA	Kcyl	RRA
WTR astigmatism	2.8% (3/104)	9.6% (10/104)	4.8% (5/104)	16.3% (17/104)	10.6% (11/104)	24.0% (25/104)
ATR astigmatism	18.6% (8/43)	2.3% (1/43)	37.2% (16/43)	13.9% (6/43)	41.8% (19/43)	25.5% (11/43)
OBL astigmatism	14.2% (2/14)	7.1% (1/14)	21.4% (3/14)	14.2% (2/14)	35.7% (5/14)	14.2% (2/14)

Abbreviations: Kcyl, keratometric corneal cylinder; RRA, residual refractive astigmatism; WTR, with-the-rule; ATR, against-the-rule; OBL, oblique.