The Effects of Angle Kappa on Clinical Results and Patient-Reported Outcomes After Implantation of a Trifocal Intraocular Lens

Figures & data

Figure 1 Schematic diagram illustrating angle kappa and the proxy vector from an eye image.

Note: The dot in the front view represents the pupillary center and “x” is the position of the visual axis at the anterior cornea.

Figure 2 Image and angle kappa calculation from the OPD-Scan III.

Notes: MPDist - the vector difference between the mesopic and photopic pupil centers; PDist – the vector difference between the photopic pupil center and the visual axis; MDist – the vector difference between the mesopic pupil center and the visual axis. The small white and purple “+” signs are the mesopic and photopic pupil centers, respectively. The larger dark “+” sign in the reflection of the light source is the location of the visual axis.

Table 1 Demographic, Biometric and Operative Details (28 Subjects, 56 Eyes)

Variables	Results^a	p
Female/male	21/7
Age (years)	68 ± 8 (43 to 83)
Pre AK (mm)	0.29 ± 0.167 (0.01 to 0.67)
Pre MRSE (D)	−0.30 ± 2.77 (−9.25 to 4.125)	0.17
Pre Cylinder (D)	0.95 ± 0.68 (0.00 to 2.50)	0.12
IOL sphere power (D)	20.44 ± 3.31 (11.5 to 26)	0.16

Note: ^amean ± standard deviation (range).

Abbreviations: AK, angle kappa magnitude; MRSE, mean refraction, spherical equivalent; D, diopter.

Table 2 Summary of Postoperative Refractive and VA Outcomes

Variable	Mean	Std.Dev.	Minimum	Maximum	Median	p
MRSE (D)	−0.08	0.25	−0.63	0.50	−0.06	0.49
Refractive cylinder (D)	0.26	0.23	0.00	0.75	0.25	0.47
UDVA (4 m)	0.04	0.09	−0.16	0.20	0.03	0.87
UCIVA (60 cm)	0.13	0.10	−0.06	0.46	0.12	0.43
UCNVA (40 cm)	0.13	0.07	0.00	0.30	0.12	0.051
UCNVA (preferred distance)	0.10	0.07	0.00	0.22	0.10	0.19
Preferred distance (cm)	38.7	2.7	33.0	45.0	38.5	0.58
DCVA	−0.03	0.06	−0.20	0.12	0.00	0.32
DCIVA	0.10	0.10	−0.06	0.42	0.10	0.18
DCNVA	0.12	0.07	0.00	0.24	0.12	0.58

Abbreviations: MRSE, mean refraction, spherical equivalent; D, diopter; UDVA, uncorrected distance visual acuity; UCIVA, uncorrected intermediate visual acuity; UCNVA, uncorrected near visual acuity; DCVA, corrected distance visual acuity; DCIVA, distance corrected intermediate visual acuity; DCNVA, distance corrected near visual acuity; logMAR, log of the minimum angle of resolution.

Figure 3 Frequency of visual disturbances reported. *Negative dysphotopsia.

Figure 4 Frequency of starbursts (top), halos (middle) and glare (bottom) by categorical magnitude of angle kappa.

Abbreviation: AK, angle kappa (vector magnitude).

Table 3 Reported Ability to See at Various Distances in Dim and Bright Light

Distance	Light	Very Poor	Poor	Fair	Good	Very Good	p
Up close	Bright	0%	0%	4%	29%	68%	0.74
	Dim	0%	11%	29%	32%	29%	0.93
Arm’s length	Bright	0%	0%	0%	18%	82%	0.98
	Dim	0%	0%	11%	57%	32%	0.44
Far Away	Bright	0%	0%	7%	25%	68%	0.56
	Dim	0%	0%	14%	50%	36%	0.93

Table 4 Change in AK Categorization After Surgery

Pre AK	Post AK			Total
	< 0.3	0.30 to < 0.40	≥ 0.4
< 0.3	23	1	2	26
0.30 to < 0.40	9	2	3	14
≥ 0.4	5	8	3	16
Total	37	11	8

Abbreviation: AK, angle kappa (vector magnitude, mm).

Table 5 Preoperative and Postoperative AK Centroid Values by Eye

	OD	OS
Preoperative X	−0.27 ± 0.19	0.01 ± 0.29
Postoperative X	−0.16 ± 0.16	0.03 ± 0.20
Preoperative Y	0.02 ± 0.14	0.01 ± 0.14
Postoperative Y	0.03 ± 0.16	0.05 ± 0.18

Note: Values are mm, mean ± standard deviation.

Figure 5 Distribution of angle kappa vectors by eye, preoperative and postoperative (radial scale in mm). (A) preoperative OD, (B) preoperative OS, (C) postoperative OD, (D) postoperative OS.

Notes: OD – right eye; OS – left eye.