A prospective pilot study using a low power piggy-back toric implantable Collamer lens to correct residual refractive error after multifocal IOL implantation

Figures & data

Figure 1 The Visian Toric Implantable Collamer Lens^® (VTICL, STAAR Surgical, USA) is available either without (V4b) or with an aquaport (V4c).

Figure 2 (A) VTICL positioned in the ciliary sulcus as a piggy-back lens. (B) mIOL positioned in the capsular bag which has a circular anterior capsulorhexis.

Abbreviations: mIOL, multifocal intraocular lens; VTICL, Visian Toric Implantable Collamer Lens^®.

Figure 3 Scheimpflug image (Pentacam^® HR, Oculus) from a patient at the 90–270° meridian 3 months after VTICL implantation: (A) distance between endothelium and VTICL: 2400 µm and (B) vault between VTICL and mIOL: 1430 µm.

Abbreviations: mIOL, multifocal intraocular lens; VTICL, Visian Toric Implantable Collamer Lens^®.

Table 1 Patient demographics and preoperative clinical information

Parameter
Patients/eyes (n)	23/24
OD/OS (n)	15/9
Age (years)
Mean (SD)	57.46 (9.66)
Median (range)	58 (30–73)
Gender; n (%)
Male	13 (56.5)
Female	10 (43.5)
Before mIOL implantation
AL (mm)
Mean (SD)	23.47 (1.57)
Median (range)	23.48 (19.99–26.43)
ACD (mm)
Mean (SD)	2.71 (0.47)
Median (range)	2.66 (1.89–3.69)
SE (D)
Mean (SD)	0.62 (3.16)
Median (range)	0.81 (−9.00–5.38)
Refractive cylinder (D)
Mean (SD)	−0.93 (1.01)
Median (range)	−0.50 (−4.25–0.00)
Before VTICL implantation
ACD (distance from endothelium to mid-iris plane) (mm)
Mean (SD)	3.29 (0.31)
Median (range)	3.27 (2.70–3.75)
UDVA (logMAR)
Mean (SD)	0.26 (0.14)
Median (range)	0.20 (0.10–0.60)
SE (D)
Mean (SD)	−0.17 (1.04)
Median (range)	0.06 (−1.88–1.63)
Refractive cylinder (D)
Mean (SD)	−0.81 (0.38)
Median (range)	−0.75 (−1.75–−0.50)
CDVA (logMAR)
Mean (SD)	−0.05 (0.06)
Median (range)	−0.10 (−0.20–0.10)

Abbreviations: OD, oculus dexter; OS, oculus sinister; AL, axial length; ACD, anterior chamber depth; SE, spherical equivalent; D, diopter; UDVA, uncorrected distance visual acuity; CDVA, corrected distance visual acuity; VTICL, Visian Toric Implantable Collamer Lens^®.

Table 2 Implanted mIOL and Visian Toric Implantable Collamer Lens^® models

Capsular bag mIOLs
mIOL models; n (%)
SN6AD1	10 (41.7)
SN6AD3	1 (4.2)
SN60D3	1 (4.2)
AT Lisa toric 909	2 (8.3)
AT Lisa tri 839	6 (25.0)
AT Lisa tri toric 939	1 (4.2)
ZMA00	1 (4.2)
Acri.Tec 466TD	2 (8.3)
mIOL power: SE (D)
Mean (SD)	21.24 (4.73)
Median (range)	21.50 (9.50–32.00)
mIOL power: cylinder (D)
Mean (SD)	0.39 (1.20)
Median (range)	0.00 (0.00–5.00)
Piggy-back Visian Toric Implantable Collamer Lens^®
VTICL size; n (%)
12.1 mm	4 (16.7)
12.6 mm	13 (54.2)
13.2 mm	7 (29.2)
VTICL model; n (%)
With aquaport (V4c)	4 (16.7)
Without aquaport (V4b)	20 (83.3)
VTICL power: SE (D)
Mean (SD)	−0.15 (1.26)
Median (range)	0.13 (−2.25–2.00)
VTICL power: cylinder (D)
Mean (SD)	0.92 (0.46)
Median (range)	1.00 (0.50–2.00)

Abbreviations: mIOL, multifocal intraocular lens; SE, spherical equivalent; D, diopter; VTICL, Visian Toric Implantable Collamer Lens^®.

Table 3 Monocular visual acuity and subjective refraction data before and after VTICL implantation

	Mean (SD) Median (range)					P-Value^a
	Preoperative	1 day	1 week	3 months	6 months
UDVA (logMAR)	0.26 (0.14)	0.23 (0.30)	0.07 (0.16)	0.01 (0.11)	−0.01 (0.09)	<0.001
	0.20 (0.10–0.60)	0.15 (−0.10–1.30)	0.00 (−0.–0.49)	0.00 (−0.10–0.20)	0.00 (−0.20–0.20)
SE (D)	−0.17 (1.04)	−0.16 (0.59)	−0.03 (0.57)	−0.08 (0.39)	0.01 (0.32)	0.301
	0.06 (−1.88–1.63)	−0.19 (−1.13–1.25)	0.00 (−0.63–2.00)	−0.13 (−0.88–0.75)	0.00 (−0.50–1.00)
CYL (D)	−0.81 (0.38)	−0.82 (0.70)	−0.34 (0.38)	−0.28 (0.29)	−0.32 (0.30)	<0.001
	−0.75 (−1.75–−0.50)	−0.50 (−2.50–0.00)	−0.25 (−1.25–0.00)	−0.25 (−1.00–0.00)	−0.25 (−1.00–0.00)
CDVA (logMAR)	−0.05 (0.06)	0.14 (0.22)	0.00 (0.12)	−0.02 (0.11)	−0.04 (0.07)	0.308
	−0.10 (−0.20–0.10)	0.05 (−0.10–0.60)	0.00 (−0.20–0.22)	−0.05 (−0.20–0.22)	0.00 (−0.20–0.10)

Note: ^aComparison of preoperative and 6-month data.

Abbreviations: UDVA, uncorrected distance visual acuity; SE, spherical equivalent; CYL, cylinder; D, diopter; CDVA, corrected distance visual acuity; VTICL, Visian Toric Implantable Collamer Lens^®.

Figure 4 Cumulative Snellen visual acuity (20/X or better) of pre- and postoperative UDVA.

Abbreviation: UDVA, uncorrected distance visual acuity.

Figure 5 Pre- and postoperative UDVA and CDVA.

Abbreviations: CDVA, corrected distance visual acuity; UDVA, uncorrected distance visual acuity.

Figure 6 Percentage of eyes achieving the stated accuracy in spherical equivalent.

Figure 7 Percentage of eyes achieving the stated accuracy in refractive cylinder.

Figure 8 Distribution of pre-and postoperative refractive astigmatism.

Figure 9 Vector representation (J0 and J45) of refractive astigmatic change after toric ICL implantation. The origin in this graph (0.0) represents an eye free of astigmatism. Abbreviation: ICL, implantable collamer lens.

Table 4 Postoperative VTICL misalignment data

	Mean (SD)
	Median (range)
TA to 1 week (°)	5.23 (4.49)
	4.00 (0.00–18.00)
TA to 3 months (°)	5.56 (4.26)
	4.50 (0.00–13.00)
TA to 6 months (°)	5.25 (4.06)
	5.00 (0.00–13.00)

Abbreviations: TA, target axis; VTICL, Visian Toric Implantable Collamer Lens^®.

Figure 10 Cumulative VTICL misalignment from the target axis over the follow-up period.

Abbreviation: VTICL, Visian Toric Implantable Collamer Lens^®.

Table 5 Pre- and postoperative ICA data

	Mean (SD) Median (range)
ICA (°) – preop	44.79 (3.51)
	44.90 (38.50–53.00)
ICA (°) – 1 week	23.02 (6.46)
	22.60 (10.90–36.00)
ICA (°) – 3 months	21.36 (7.19)
	21.50 (10.80–36.50)
ICA (°) – 6 months	23.55 (9.29)
	22.90 (11.00–44.90)

Abbreviation: ICA, iridocorneal angle.

Table 6 Postoperative clinical outcomes regarding vault (distance between the VTICL and the mIOL) and the distance between the endothelium and the VTICL

	Mean (SD) Median (range)
	1 week	3 months	6 months
Vault total (µm)	1532 (295)	1385 (240)	1385 (302)
	1483 (1095–2115)	1355 (860–1795)	1425 (1000–2075)
Distance endothelium to VTICL (µm)	2085 (531)	2197 (456)	2205 (524)
	2080 (1050–2950)	2210 (1530–2985)	2123 (1450–3300)

Abbreviations: VTICL, Visian Toric Implantable Collamer Lens^®; mIOL, multifocal intraocular lens.

Table 7 Preoperative versus 6-month postoperative IOP

	Mean (SD) Median (range)
	Preoperative	6 months
IOP all eyes (mmHg) n=23	14.49 (2.74) 14.00 (10.00–21.30)	14.32 (2.27) 14.00 (10.00–19.30)
IOP with Aquaport (mmHg) n=4	15.43 (0.96) 15.85 (14.00–16.00)	13.83 (2.68) 14.65 (10.00–16.00)
IOP without Aquaport (mmHg) n=19	14.29 (2.96) 14.00 (10.00–21.30)	14.43 (2.25) 14.00 (11.30–19.30)