Comparative evaluation of toric intraocular lens alignment and visual quality with image-guided surgery and conventional three-step manual marking

Figures & data

Figure 1 Postoperative assessment of toric IOL alignment with ray tracing aberrometer in a case in group I (conventional manual marking). A 6° deviation from target axis of implantation is present.

Abbreviation: IOL, intraocular lens.

Figure 2 Postoperative assessment of toric IOL alignment with ray tracing aberrometer in a case in group II (image-guided surgery). A 1° deviation from target axis of implantation is present.

Abbreviation: IOL, intraocular lens.

Table 1 Demographic details and preoperative characteristics of cases undergoing toric IOL implantation

Demographic variables	Group I (manual marking) N=40	Group II (Callisto assisted) N=40	p-value
Age (years)	63.1±13.7	60.1±10.3	0.271
Sex (M:F)	17:23	19:21	0.822
Right eye: left eye	24:16	18:22	0.263
Preoperative characteristics
Corneal cylinder (D)	2.1±0.9	2.5±0.9	0.057
Defocus equivalent	1.2±2.8	2.0±3.2	0.211
Keratometry 1	42.6±1.8	42±1.8	0.148
Keratometry 2	44.6±1.9	44.4±2.2	0.724
UDVA (logMAR units)	0.78±0.37	0.97±0.28	0.013
CDVA (logMAR units)	0.56±0.38	0.59±0.29	0.746
IOP (mmHg)	14.9±3.01	14.4±3.04	0.508
Target axis of implantation	100.2±74.8	104.2±68.8	0.804

Abbreviations: M, male; F, female; D, Diopter; UDVA, uncorrected distance visual acuity; CDVA, corrected distance visual acuity; logMAR, logarithm of minimum angle of resolution; IOP, intraocular pressure.

Table 2 Postoperative visual outcomes and toric IOL alignment in cases undergoing toric IOL implantation with manual marking or image-guided surgery

Outcome measures	Group I (manual marking) N=40	Group II (Callisto assisted) N=40	p-value
Refractive sphere	0.39±0.44	0.15±0.79	0.105
Refractive cylinder	−0.89±0.35	−0.64±0.36	0.003
Corneal cylinder	2.1±0.9	2.3±1.2	0.474
Defocus equivalent	0.01±0.2	0.07±0.3	0.208
UDVA (logMAR units) POD 1	0.055±0.09	0.03±0.07	0.184
CDVA (logMAR units) POD 1	0.01±0.03	0.005±0.02	0.402
UDVA (logMAR units) POD 30	0.025±0.06	0.017±0.05	0.541
CDVA (logMAR units) POD 30	0.008±0.03	0.005±0.02	0.649
IOP (mmHg)	15.2±2.9	14.4±2.9	0.272
Axis of IOL implantation	82.6±72.3	104.6±69.0	0.169
Deviation from target axis (POD 1)	5.8±3.7	3.7±2.8	0.005
Deviation from target axis (POD 30)	5.5±3.3	3.6±2.6	0.005

Note: p-values less than 0.05 are shown in bold.

Abbreviations: D, Diopter; UDVA, uncorrected distance visual acuity; CDVA, corrected distance visual acuity; logMAR, logarithm of minimum angle of resolution; IOP, intraocular pressure; IOL, intraocular lens; POD, postoperative day.

Table 3 Assessment of visual quality in cases undergoing toric intraocular lens alignment with manual marking or image-guided surgery

Visual quality parameters	Group I (manual marking) N=40	Group II (Callisto assisted) N=40	p-value
Postoperative day 1
Strehl ratio internal	0.051±0.056	0.109±0.142	0.019
Strehl ratio total	0.090±0.104	0.136±0.182	0.170
MTF internal 5 cpd	0.344±0.214	0.484±0.235	0.007
MTF internal 10 cpd	0.172±0.115	0.249±0.174	0.021
MTF internal 15 cpd	0.107±0.072	0.153±0.121	0.042
MTF internal average	0.218±0.085	0.273±0.115	0.016
MTF total 5 cpd	0.517±0.202	0.550±0.209	0.480
MTF total 10 cpd	0.249±0.146	0.273±0.178	0.508
MTF total 15 cpd	0.162±0.103	0.187±0.119	0.327
MTF total average	0.282±0.101	0.302±0.109	0.406
Postoperative day 30
Strehl ratio internal	0.075±0.081	0.149±0.162	0.012
Strehl ratio total	0.101±0.085	0.134±0.120	0.160
MTF internal 5 cpd	0.373±0.250	0.492±0.271	0.045
MTF internal 10 cpd	0.190±0.142	0.264±0.186	0.051
MTF internal 15 cpd	0.110±0.078	0.165±0.129	0.023
MTF internal average	0.226±0.102	0.282±0.130	0.036
MTF total 5 cpd	0.546±0.179	0.599±0.215	0.245
MTF total 10 cpd	0.277±0.136	0.312±0.169	0.301
MTF total 15 cpd	0.197±0.158	0.212±0.168	0.675
MTF total average	0.299±0.088	0.319±0.107	0.343

Note: p-values less than 0.05 are shown in bold.

Abbreviations: MTF, modulation transfer function; cpd, cycles per degree.

Table 4 Correlation between postoperative visual quality and deviation from target axis of implantation of toric intraocular lens on postoperative days 1 and 30

Correlation parameters	Deviation from target axis, day 1		Deviation from target axis, day 30
	Pearson’s correlation coefficient	p-value	Pearson’s correlation coefficient	p-value
Strehl ratio internal	−0.621	<0.001	−0.730	<0.001
Strehl ratio total	−0.396	<0.001	−0.469	<0.001
MTF internal 5 cpd	−0.788	<0.001	−0.795	<0.001
MTF internal 10 cpd	−0.710	<0.001	−0.794	<0.001
MTF internal 15 cpd	−0.671	<0.001	−0.772	<0.001
MTF internal average	−0.771	<0.001	−0.828	<0.001
MTF total 5 cpd	−0.307	0.006	−0.313	0.005
MTF total 10 cpd	−0.322	0.004	−0.206	0.067
MTF total 15 cpd	−0.309	0.005	−0.232	0.038
MTF total average	−0.320	0.004	−0.239	0.033

Abbreviations: MTF, modular transfer function; cpd, cycles per degree.