Toric Intraocular Lenses for the Management of Corneal Astigmatism at the Time of Cataract Surgery

Aims/Background. To assess astigmatic outcomes with the use of toric intraocular lenses (IOLs) for patients with significant amounts of corneal astigmatism undergoing cataract surgery. Methods. This audit was conducted in a UK ophthalmology department and included 48 eyes of 42 patients. Surgery was performed during 2019 in patients with 2.50 diopters (D) or more corneal astigmatism. Anterior keratometry readings were used to determine the toric IOL power. Vector analysis using the Alpins method was used to assess changes in astigmatism pre to postoperatively. Results. There were 18 right and 26 left eyes included. In terms of gender, 61% of patients were female and 39% were male. The mean (±standard deviation (SD)) age was 70 (±11) years. The mean (±SD) axial length, K1, K2, and delta K was 23.55 (±1.4) mm, 42.71 (±1.39) D, 45.78 (±1.60) D, and 3.01 (±0.89) D, respectively. Postoperatively, the median spherical, cylinder, and spherical equivalent refraction was 0.00 D, −1.00 D, and 0.00 D, respectively. Postoperatively, 41% of the eyes had ≤0.50 D of spectacle astigmatism and 80% had ≤1.00 D. No patient required a secondary procedure to reposition the IOL from rotation. In vector analysis with the use of polar diagrams, there was a tendency for overcorrection of with-the-rule astigmatism and undercorrection of against-the-rule astigmatism. Conclusions. Significant reductions in astigmatism can be achieved with the use of toric IOLs in patients undergoing cataract surgery. Further improvements may be possible with surgeon-specific determination of their surgically induced astigmatism and flattening effect from the main corneal incision. Furthermore, the use of an optical biometer that directly measures the posterior corneal curvature and permits automatic toric IOL power determination with modern formulas avoiding the need for manual data entry may reduce the risk of human error and improve visual and refractive outcomes.

Long-term changes in the refractive effect of a toric intraocular lens on astigmatism correction

Purpose To examine the long-term changes in the astigmatism-correcting effect of a toric intraocular lens (IOL) after stabilization of surgically induced astigmatic changes due to cataract surgery. Methods Unilateral eyes of 120 patients that received a toric IOL for against-the-rule (ATR) or with-the-rule (WTR) astigmatism were enrolled. Manifest refractive and anterior corneal astigmatism, and ocular residual astigmatism which is mainly derived from internal optics were examined preoperatively, at approximately 2 months postoperatively (baseline) and at 5 ~ 10 years postbaseline. The astigmatism was decomposed to vertical/horizontal (Rx) and oblique components (Ry), which was compared between baseline and 5 ~ 10 years postbaseline. Results In the eyes having ATR astigmatism, the mean Rx and Ry of the manifest refractive and corneal astigmatism significantly changed toward ATR astigmatism between the baseline and 5 ~ 10 years postbaseline (p ≤ 0.0304), but those of ocular residual astigmatism did not change significantly between the 2 time points. In the eyes having WTR astigmatism, the Rx and Ry of refractive, corneal, and ocular residual astigmatism did not change significantly between the 2 time points. Double-angle plots revealed an ATR shift in refractive and corneal astigmatism and no marked change in the ocular residual astigmatism in the eyes with ATR astigmatism, and there is no change in this astigmatism in the eyes with WTR astigmatism. Conclusion The long-term changes with age in the effect of a toric IOL significantly deteriorated due to an ATR shift of corneal astigmatism in the eyes having ATR astigmatism, while it was maintained in eyes having WTR astigmatism, suggesting that ATR astigmatism should be overcorrected.

Calculation of Toric Intraocular Lens Power with the Barrett Calculator and Data from Three Keratometers

Aim. To investigate the interdevice agreement for differences in toric power calculated using data on anterior corneal astigmatism obtained with corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam). Methods. The analysis included 101 eyes (101 subjects) with regular astigmatism. The main outcome measures were corneal cylinder power, axis of astigmatism, and keratometry values. Toricity and toric IOL power were calculated using the online Barrett toric calculator. Interdevice agreement for measurement and calculation was assessed using a paired sample t-test and a nonparametric test. Results. Significant interdevice differences were noted in the magnitude of astigmatism and flat, steep, and mean keratometry values between iTrace and IOLMaster (all P < 0.01 ); in flat, steep, and mean keratometry values (all P < 0.001 ) but not in the magnitude of astigmatism ( P = 0.325 ) between iTrace and Pentacam; and in the magnitude of astigmatism and steep and mean keratometry values (all P < 0.01 ) but not in flat keratometry values ( P = 0.310 ) between IOLMaster and Pentacam. The toric IOL power calculated using data from the three devices showed the following trend: iTrace > IOLMaster (0.49 ± 0.36, P < 0.001 ) and Pentacam (0.39 ± 0.42, P < 0.001 ) and Pentacam was <IOLMaster (−0.10 ± 0.39, P = 0.009 ). There were differences in toricity calculated using data from the three devices ( P = 0.004 ). Conclusions. Differences in toric IOL power and toricity calculated using anterior keratometry data from iTrace, IOLMaster 500, and Pentacam should be noted in clinical practice.

Astigmatic correction of simultaneous femtosecond laser-assisted cataract surgery (FLACS) with intrastromal arcuate keratotomy (ISAK) versus Toric intraocular Lens Impantation with conventional phacoemulsification

Background To compare the efficacies in astigmatic correction of simultaneous femtosecond laser-assisted cataract surgery (FLACS) with intrastromal arcuate keratotomy (ISAK) versus toric intraocular lens (IOL) implantation with conventional phacoemulsification in moderate astigmatism. Methods A retrospective chart review was conducted for patients who had undergone cataract surgery by one surgeon. We identified patients with preoperative corneal astigmatism from + 0.75 to + 2.00 diopters (D) who had undergone astigmatic correction with FLACS with ISAK or toric IOL implantation with conventional phacoemulsification. We measured the visual acuity, intraocular pressure, automated keratometer, manifest refraction, and topography preoperatively and 1-day, 1-month, 3-month, and 6-month postoperatively. The vector analysis of refractive astigmatism was performed. Results Of a total of 48 eyes of 48 patients, 27 eyes of 27 patients had FLACS with ISAK (AK group), and 21 eyes of 21 patients had conventional cataract surgery with toric IOL implantation (toric IOL group). Refractive astigmatism was significantly decreased in both groups. The mean preoperative and 6-month postoperative refractive astigmatism were 1.85 ± 1.07 and 0.99 ± 0.51 D, respectively, in the AK group (P = 0.028), and 1.84 ± 0.81 and 0.68 ± 0.21 D, respectively, in the toric IOL group (P < 0.001). There was no significant difference in refractive astigmatism between the two groups at 6-month postoperatively (0.99 ± 0.51 vs 0.68 ± 0.21 D, P = 0.057). At 6-month postoperatively, parameters for vector analysis of refractive astigmatism showed no statistical difference between the two groups. Corneal astigmatism was significantly decreased in the AK group. Corneal astigmatism from topography and the automated keratometer were significantly lower in the AK group 6-month postoperatively compared to toric IOL group (0.94 ± 0.40 vs. 1.53 ± 0.46 D, P = 0.018 for topography; and 0.98 ± 0.69 vs. 1.37 ± 0.41 D, P = 0.032 for the automated keratometer). Conclusions FLACS with ISAK could be an effective procedure for reducing astigmatism as well as toric IOL implantation in cataract surgery.

ĐÁNH GIÁ ĐỘ XOAY TRỤC CỦA THỦY TINH NHÂN TẠO ĐA TIÊU ĐIỀU CHỈNH LOẠN THỊ

Mục tiêu: đánh giá độ xoay trục của thể thủy tinh nhân tạo (TTTNT) đa tiêu điều chỉnh loạn thị Acrysof ReSTOR Toric (ART) trên bệnh nhân được phẫu thuật phaco đặt TTTNT ART. Đối tượng và phương pháp nghiên cứu: Nghiên cứu can thiệp lâm sàng tiến cứu trên 52 mắt của 46 bệnh nhân đục thể thủy tinh kèm loạn thị giác mạc từ 1,00-3,00D, được phẫu thuật phaco đặt thể thủy tinh nhân tạo đa tiêu điều chỉnh loạn thị Acrysof ReSTOR Toric. Thời gian theo dõi sau 1 tuần, 1 tháng, 3 tháng, 6 tháng, 1 năm bao gồm độ xoay trục IOL, thị lực, độ loạn thị tồn dư. Kết quả: Sau mổ 1 tuần, 15,38% mắt lệch trục IOL trong đó 75% dưới 3 độ, 25% từ 3 độ đến 5 độ, độ xoay trục trung bình 2,42±1,12˚. Sau mổ 1 tháng đến 12 tháng có 17,31% mắt xoay trục IOL, 100% dưới 5 độ, độ xoay trục trung bình là 2,28±1,34˚. Khi trục IOL xoay dưới 3 độ, độ loạn thị tồn dư trung bình là -0,12±0,08 D, khi trục IOL xoay trên 3 độ, độ loạn thị tồn dư trung bình là -0,37±0,26. Trục IOL xoay càng nhiều thì độ loạn thị tồn dư càng lớn với p<0,05. Những mắt bị lệch trục IOL có thị lực nhìn xa, nhìn gần và nhìn trung gian chưa chỉnh kính sau mổ thấp hơn so với những mắt không bị lệch trục IOL với p<0,001. Kết luận: Điều chỉnh loạn thị bằng toric IOL đã trở thành một lựa chọn cho nhiều phẫu thuật viên nhãn khoa. Đánh giá độ xoay trục IOL là một bước quan trọng không thể thiếu khi theo dõi bệnh nhân sau phẫu thuật bởi nó ảnh hưởng trực tiếp đến kết quả phẫu thuật cũng như sự hài lòng của bệnh nhân.

Influence of frosted haptics on rotational stability of toric intraocular lenses

We investigated the unfolding property and rotational stability of a new toric intraocular lens (IOL); TECNIS toric II (toric-II, ZCW, Johnson & Johnson) that is an improved version of TECNIS toric IOL (toric-I, ZCV). Both IOLs are based on an identical platform, except for the frosted haptics with toric-II IOL. The study consisted of two parts; experimental study and clinical, retrospective, case series. Experimental study indicated that the overall time from IOL ejection to unfolding to 11 mm was significantly shorter with toricII than toric-I IOLs (p = 0.032), due to the earlier separation of the haptics from the optic with toric-II IOL. Clinical study included 131 eyes of 99 patients who had undergone phacoemulsification and toric IOL implantation. At 3 months postoperatively, toric-II IOL showed significantly better rotational stability than toric-I IOL, including smaller residual manifest astigmatism (p = 0.018), less amount of axis misalignment from the intended axis (p = 0.04), lower incidence of misalignment > 10º (p = 0.0044), and less degree of prediction errors (p = 0.043). Postoperative uncorrected distance visual acuity tended to be better in the toric-II than in the toric-I groups, with marginal statistical difference (p = 0.057). TECNIS toric II IOL with the frosted haptics showed significantly better rotational stability than its predecessor, probably due to quicker unfolding and greater friction with the capsular bag.

Refractive Status in Eyes Implanted with Toric and Nontoric Intraocular Lenses during Combined Cataract Surgery and Microhook Ab Interno Trabeculotomy

Purpose. To compare the refractive status between eyes implanted with toric and nontoric intraocular lenses (IOLs) during combined cataract surgery and microhook ab interno trabeculotomy (μLOT), a minimally invasive glaucoma surgery (MIGS). Methods. Twenty eyes of 20 patients who had open-angle glaucoma, cataract, and preexisting regular corneal astigmatism exceeding 1.5 diopters (D) and underwent combined μLOT and phacoemulsification were recruited retrospectively. Ten eyes were implanted with a toric IOL and 10 eyes with a nontoric IOL. The primary outcomes were the uncorrected visual acuity (UCVA) and refractive cylinder at 3 months postoperatively. Results. The mean UCVA of the toric IOL group (logarithm of the minimum angle of resolution (logMAR), 0.23 ± 0.25) was significantly better than that of the nontoric IOL group (logMAR, 0.45 ± 0.26) at 3 months postoperatively ( p < 0.05 ). The mean absolute residual refractive cylinder of the nontoric IOL group (2.25 ± 0.62 D) was significantly greater than that of the toric IOL group (1.30 ± 0.68 D) ( p < 0.05 ). Postoperatively, 60% of eyes in the toric IOL group and 10% in the nontoric IOL group had an absolute refractive astigmatism level of 1.5 D or less. Surgically induced astigmatism (0.77 ± 0.43 D for toric group and 0.60 ± 0.32 D for nontoric group) and IOP reduction (33.9 ± 15.6% for toric group and 29.4 ± 11.7% for nontoric group) were not different between groups. Conclusions. Use of toric IOL during combined cataract surgery and μLOT is possible and better than not, but physician should prevent their patient of persisting residual astigmatism. The study was registered at https://www.umin.ac.jp/, and the clinical trial accession number is https://clinicaltrials.gov/ct2/show/UMIN000043141.