Toric Group Research Articles

Rotational performance and corneal astigmatism correction during cataract surgery: Aspheric toric intraocular lens versus aspheric nontoric intraocular lens with opposite clear corneal incision

To compare the astigmatism-reducing effect of an aspheric toric intraocular lens (IOL) and an aspheric nontoric IOL with an opposite clear corneal incision (OCCI) in cataract surgery. Vienna Institute for Research in Ocular Surgery, Hanusch Hospital, Vienna, Austria. Prospective randomized clinical study. Patients with low to moderate corneal astigmatism scheduled for cataract surgery received an aspheric toric IOL (Lentis L-312T) or an aspheric nontoric IOL (Lentis L-312) combined with an OCCI. Keratometry and corneal tomography were performed 1 hour, 1 week, 3 months and 9 months postoperatively. Postoperative residual astigmatism was measured using an autorefractor. Rotational toric IOL stability was analyzed using retroillumination photography. Fifty-five patients were included. Three months postoperatively, the mean reduction in corneal astigmatism was 0.67 diopter (D) ± 0.58 (SD) in the toric group and 0.18 ± 0.52 D in the nontoric-OCCI group. The mean uncorrected distance visual acuity was 0.29 ± 0.30 logMAR and 0.09 ± 0.18 logMAR, respectively (P=.02). The mean refractive astigmatism was 1.02 ± 0.54 D and 0.68 ± 0.52 D, respectively (P=.05). One hour, 3 months, and 9 months postoperatively, the mean absolute IOL misalignment of toric IOLs was 4.99 ± 4.66 degrees, 13.59 ± 11.29 degrees, and 19.90 ± 14.48 degrees, respectively. The toric IOL tended to rotate significantly postoperatively. Visual acuity was good in both groups. Residual refractive cylinder was significantly lower in the toric IOL group. No author has a financial or proprietary interest in any material or method mentioned.

High-cylinder toric intraocular lens implantation versus combined surgery of low-cylinder intraocular lens implantation and limbal relaxing incision for high-astigmatism eyes.

Clinical outcomes were compared between high-cylinder toric intraocular lens (IOL) implantation and the combined surgery of low-cylinder toric IOL implantation and limbal relaxing incision (LRI) for correcting preexisting high-amplitude corneal astigmatism. Fifty-seven eyes with preexisting corneal astigmatism of 2.5 diopter (D) or greater were divided into the following two groups: (1) eyes that underwent Alcon AcrySof® IQ Toric T6, T7, T8, or T9 IOL implantation (toric group); and (2) eyes that underwent the combined surgery of AcrySof® IQ Toric T5 IOL implantation and LRI (LRI group). Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest, refractive and corneal cylinder (MC, RC, CC), were compared postoperatively. Corneal and ocular higher-order aberrations (HOA) were also compared. At 1 day postoperative, UCVA was significantly better and MC and RC were significantly less in the toric group, however, at 1 and 6 months postoperative, there was no significant difference in those parameters. Postoperative corneal and ocular HOA were significantly greater in the LRI Group. For correcting astigmatism in eyes with a high amount of preexisting astigmatism, high-cylinder toric IOL implantation achieves better clinical outcomes, especially in the early postoperative period, than the combined procedure of moderate-cylinder toric IOL implantation and LRI.

Effect of preoperative corneal astigmatism orientation on results with a toric intraocular lens

To compare the Acrysof IQ toric intraocular lens (IOL) and the Acrysof IQ aspheric nontoric IOL and evaluate the effect of preoperative corneal astigmatism orientation on results. Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan. Comparative case series. This retrospective chart review comprised patients with cataract and preoperative corneal astigmatism between 1.0 diopter (D) and 2.5 D having toric IOL (toric group) or aspheric nontoric IOL (nontoric group) implantation. Eyes were grouped depending on the preoperative axis of corneal astigmatism; that is, with the rule (WTR), against the rule (ATR), and oblique. Preoperative and postoperative analyses included uncorrected (UDVA) and corrected (CDVA) distance visual acuities and cylindrical power preoperatively and 3 months postoperatively. The postoperative CDVA was not significantly different between the 2 IOLs; however, the postoperative UDVA was significantly better in the toric group than in the nontoric group (P<.0001). The postoperative residual cylindrical power was significantly smaller in the toric group (P<.0001). In eyes with ATR and oblique astigmatism, the mean postoperative UDVA was significantly better in the toric group, whereas there were no differences between the 2 groups in patients with WTR astigmatism. There was significant improvement in postoperative cylinder and UDVA with toric IOLs compared with nontoric IOLs. With a superior corneal incision, the benefits of astigmatism correction with the toric IOL were more significant in patients with ATR and oblique astigmatism than in those with WTR astigmatism.

Comparative analysis of the visual and refractive outcomes of an aspheric diffractive intraocular lens with and without toricity

To analyze and compare the postoperative visual and refractive outcomes and patients' visual satisfaction after implantation of an aspheric or an aspheric toric multifocal diffractive intraocular lens (IOL) in eyes with equivalent biometric characteristics. Private clinic, Munich, Germany. Comparative case series. Patients having cataract surgery were assigned to 1 of 2 groups: aspheric, which had AT Lisa 809M IOL implantation, and aspheric toric, which had AT Lisa 909M IOL implantation (corneal toricity ≥0.75 diopter [D]). Visual and refractive postoperative outcomes were evaluated, as was the patient's ability to perform daily tasks related to vision and the incidence of photic phenomena. The aspheric group comprised 77 eyes (42 patients) and the aspheric toric group, 26eyes (17 patients). A significant improvement in corrected distance and near visual acuity was observed postoperatively in both groups, as was a significant reduction in the astigmatic component J0 (P<.01). The aspheric toric group had significantly better uncorrected intermediate visual acuity (P=.01). In both groups, the postoperative astigmatic power vectors and spherical equivalent were within ±0.50 D in 100% of eyes and in more than 88% of eyes, respectively. No statistically significant differences were found in any subjective patient questionnaire item. There was no difference in the incidence of photic phenomena between the groups (P≥0.16). The addition of a toric surface to the aspheric diffractive multifocal platform resulted in a comparable visual performance and ability to perform visual tasks. The author has no financial or proprietary interest in any material or method mentioned.

Pacientes com astigmatismo submetidos à cirurgia de catarata: LIO tórica x LIO asférica?

Compare the visual acuity of patients who underwent cataract surgery by phacoemulsification with IOL AcrySof(®) toric implantation versus AcrySof(®) IQ and evaluate the reduction of cylindrical diopters (CD) in the postoperative period. Analytical and retrospective study of 149 eyes with 1 or more diopters of regular symmetrical keratometric astigmatism, which underwent cataract surgery by phacoemulsification. The eyes were divided into two groups: the toric group with 85 eyes and the non-toric group with 64 eyes. In the pre-operative phase, topographic data and refraction of each eye to be operated were assessed. In the postoperative phase, refraction and visual acuity with and without correction were measured. The preoperative topographic astigmatism ranged from 1.00 to 5.6 DC in both groups. Average reduction of 1.37 CD (p<0.001) and 0.16 CD (p=0.057) was obtained for the toric and non-toric group when compared to the refractive astigmatism, respectively. Considering visual acuity without correction (NCVA), the toric group presented 44 eyes (51.7%) with NCVA of 0 logMAR (20/20) or 0.1 logMAR (20/25) and the toric group presented 7 eyes (10.93%) with these same NCVA values. The results show that patients with a significant keratometric astigmatism presented visual benefits with the toric IOL implantation. The reduction of the use of optical aids may be obtained provided aberrations of the human eye are corrected more accurately. Currently, phacoemulsification surgery has been used not only for functional improvement, but also as a refraction procedure.

Combined 25-gauge vitrectomy and cataract surgery with toric intraocular lens with idiopathic epiretinal membrane

To evaluate the stability of axis rotation, astigmatism correction, and improvement in uncorrected distance visual acuity (UDVA) up to 6 months postoperatively using an astigmatism-correcting intraocular lens (IOL) in a 25-gauge transconjunctival sutureless vitrectomy combined with cataract surgery. Department of Ophthalmology, Kagawa University Faculty of Medicine, Kagawa, Japan. Prospective nonrandomized interventional study. Eyes with a preoperative corneal cylinder of more than 0.75 diopter (D) had a triple procedure for idiopathic epiretinal membrane (ERM) using an Acrysof IQ toric IOL. Outcome measures were the amount of IOL axis rotation up to 3 months postoperatively, UDVA, corrected distance visual acuity, and corneal and refractive astigmatism up to 6 months postoperatively. A comparison was performed between patients with a target postoperative spherical refraction of emmetropia (toric emmetropic group) and patients who previously had a triple procedure for idiopathic ERM using a nontoric IOL (control group). The mean IOL axis rotation from the end of surgery until 3 months postoperatively was 3.67 degrees ± 3.13 (SD). Six months postoperatively, the mean corneal and refractive cylinders were 1.32 ± 0.61 D and 0.51 ± 0.31 D, respectively, showing a significant difference (P<.0001, paired t test). In addition, the mean UDVA was significantly improved 6 months postoperatively in the control and toric emmetropic group (0.57 logMAR versus 0.35 logMAR) (P=.028), although the toric group was more improved than the control group. In vitrectomy (triple procedure) for idiopathic ERM with a toric IOL, postoperative IOL axis stability was similar to that reported for cataract surgery alone. Furthermore, the UDVA was better than with implantation of a spherical IOL.

Astigmatism correction with toric intraocular lenses: wavefront aberrometry and quality of life

Background/aimTo evaluate wavefront aberrations and subjective quality of life after toric intraocular lens (TIOL) implantation.MethodsThree groups of subjects who underwent unilateral cataract surgery with intraocular lens (IOL) implantation were compared:...

A Symmetry Result on Submanifolds of Space Forms and Applications

In this paper we prove a symmetry result on submanifolds of codimension one in a (n + 1)-dimensional space form, related to the geodesic distance and to the normal curvature of some fixed vector field. As applications we will prove sphere characterization type theorems for Kahler manifolds endowed with a toric group action.

Effects of the toric intraocular lens on correction of preexisting corneal astigmatism

To examine the effects of a toric intraocular lens (IOL) on the correction of preexisting corneal astigmatism after cataract surgery. Fifty eyes that underwent phacoemulsification were enrolled in three group: (1) eyes with corneal astigmatism ≥1.0 diopter (D) that received a toric IOL (Alcon SN6AT) (toric), (2) eyes with astigmatism ≥1.0 D that received a nontoric IOL (high-astigmatism group), and (3) eyes with astigmatism <1.0 D that received the nontoric IOL (low-astigmatism group). Refractive and corneal astigmatism, astigmatic change, and uncorrected visual acuity (UCVA) were examined. The postoperative refractive astigmatism in the toric and low-astigmatism groups was significantly lower than that of the high-astigmatism group (P ≤ 0.0040), and the reduction in the refractive astigmatism was greater in the toric than in the high- and low-astigmatism groups (P < 0.0001), although the corneal astigmatism was greatest in the toric group, followed by the high- and low-astigmatism groups (P < 0.0001). The mean UCVA in the toric and low-astigmatism groups was better than that in the high-astigmatism group (P < 0.0001). The toric IOL proved effective in astigmatism correction, and both the residual astigmatism and UCVA in the eyes with the the toric IOL were better than those in the eyes with high astigmatism and were comparable to those in the eyes with low astigmatism.

Higher-order aberrations and visual function in pseudophakic eyes with a toric intraocular lens

To compare higher-order aberrations (HOAs) and visual function in eyes with a toric intraocular lens (IOL) and eyes with a nontoric IOL. Hayashi Eye Hospital, Fukuoka, Japan. Case-control study. Eyes that had phacoemulsification were enrolled in 1 of the following 3 groups: (1) preoperative corneal astigmatism of 1.00 diopter (D) with a toric IOL (toric group), (2) astigmatism of 1.00 D or more with a nontoric IOL (high-astigmatism group), and (3) astigmatism less than 1.00 D with a nontoric IOL (low-astigmatism group). Ocular and corneal HOAs were measured using a wavefront analyzer. Photopic and mesopic visual acuities at high- to low-contrast visual targets were measured using a contrast sensitivity tester. The mean ocular and corneal total HOAs and 3rd-order aberrations in the toric and high-astigmatism groups tended to be greater than in the low-astigmatism group; HOAs and 3rd-order aberrations at 3 months and HOAs at 6 months were significantly different (P ≤.0403). The mean corrected visual acuity did not differ significantly between groups. However, photopic low-contrast visual acuity (LCVA) and mesopic high- to low-contrast visual acuity was significantly worse in the toric and high-astigmatism groups than in the low-astigmatism group (P ≤.0210). Postoperatively, ocular and corneal HOAs were greater in eyes with a toric IOL and in eyes with high preexisting corneal astigmatism than in eyes with low preexisting astigmatism, which impaired photopic LCVA and mesopic visual acuity. No author has a financial or proprietary interest in any material or method mentioned.

Resident experience with toric and multifocal intraocular lenses in a public county hospital system

To study the outcomes of toric and multifocal intraocular lens (IOL) implantation performed by resident surgeons. Parkland Health and Hospital System, Dallas, Texas, USA. Case series. Patients seen between July 2008 and May 2011 and meeting inclusion criteria (including >1.0 diopter [D] of astigmatism in toric group and <0.75 D astigmatism in multifocal group) were offered implantation of the study IOLs. Major outcomes were uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) and, for the multifocal IOL, near visual acuity. Residents were surveyed about their knowledge regarding these IOLs. Seventy-nine eyes of 60 patients received an Alcon Acrysof toric IOL. Eighteen eyes of 10patients received an Alcon Acrysof Restor IOL. In the toric group, 57% of eyes achieved a postoperative UDVA of 20/25 or better and 90% achieved 20/40 or better. The CDVA was 20/25 or better in 92% of eyes. The mean refractive cylinder was 1.69 D preoperatively and 0.38 D postoperatively. In the multifocal group, 78% of patients achieved a UDVA of 20/25 or better and 94% achieved 20/40 or better. All patients had a CDVA of 20/25 or better. Near vision was Jaeger 3 or better in 94%. The survey showed that residents have a strong comfort level with preoperative and surgical techniques for premium IOLs after their experience in the residency setting. Residents in public county hospitals can be taught to use premium IOLs with good success rates, comparable to those in other published studies. Dr. McCulley is a consultant to Alcon Laboratories, Inc., and Dr. Aggarwal is on the speaker's bureau for Alcon Laboratories, Inc. No author has a financial or proprietary interest in any material or method mentioned.

A Note on the Complete Rotational Invariance of Biradial Solutions to Semilinear Elliptic Equations

Abstract We investigate symmetry properties of solutions to equations of the form -Δu = + f(|x|, u) in ℝN for N ≥ 4, with at most critical nonlinearities. By using geometric arguments, we prove that solutions with low Morse index (namely 0 or 1) and which are biradial (i.e. are invariant under the action of a toric group of rotations), are in fact completely radial. A similar result holds for the semilinear Laplace-Beltrami equations on the sphere. Furthermore, we show that the condition on the Morse index is sharp. Finally we apply the result in order to estimate best constants of Sobolev type inequalities with different symmetry constraints.

Comparison of the AcrySof SA60 spherical intraocular lens and the AcrySof Toric SN60T3 intraocular lens outcomes in patients with low amounts of corneal astigmatism

Toric intraocular lenses (IOLs) have been reported to be an effective method of reducing postoperative refractive astigmatism and spectacle dependence following cataract surgery. This study compares a series of patients with low corneal astigmatism implanted with either the AcrySof SA60 spherical IOL or the AcrySof Toric SN60T3 IOL in a quantitative fashion to establish the merit of toric IOLs in these cases. A retrospective chart audit was undertaken of 12 patients receiving the AcrySof Toric SN60T3 IOL (1.5 DC, Alcon, Fort Worth) and 10 patients receiving the AcrySof SA60 IOL (Alcon, Fort Worth). Preoperative corneal astigmatism and postoperative refractive astigmatism were recorded and converted into a non-signed Astigmatic Power Vector for statistical analysis. Postoperative vision (uncorrected visual acuity, UCVA) was also recorded for both groups. A statistical analysis was performed to examine for differences in outcomes between groups. The mean magnitude of the preoperative corneal Astigmatic Power Vector was not significantly different between the groups. The mean magnitude of the postoperative refractive vector was significantly smaller in the AcrySof Toric group. The mean UCVA was significantly better in the AcrySof Toric group compared with the AcrySof group. The AcrySof Toric IOL provides a significant improvement in postoperative astigmatism and UCVA when compared statistically with its spherical counterpart for patients with low degrees of corneal astigmatism.

Contact Lens Related Quality of Life in Patients With Keratoconus

To assess the impact of the different types of contact lenses (CLs) on quality of life (QoL) in patients with keratoconus based on self-reported results from The Contact Lens Impact on Quality of Life (CLIQ) Questionnaire. Consecutive keratoconus patients who wore CLs (rigid gas permeable [RGP], hybrid or soft toric) at least in one eye were asked to complete the CLIQ questionnaire on the Cornea Service, Wills Eye Institute. A total of 71 patients with a mean age of 42.6 +/- 13.1 year were included in the study. One eye of each patient was included in the study. Of these, 40 eyes used rigid gas-permeable lenses, 20 eyes used hybrid lenses and 11 eyes used soft toric lenses. The mean CLIQperson measure was 45.5 +/- 8.2 in RGP group, 45.4 +/- 7.5 in hybrid group and 48.4 +/- 10.5 in soft toric group. There was no significant difference among the three groups in self-reported results from the CLIQ questionnaire (P = 0.8). Subjects with keratoconus who wear RGP, hybrid or soft toric CLs, reported similar contact lens impact on their QoL.

Toric intraocular lens versus opposite clear corneal incisions to correct astigmatism in eyes having cataract surgery

To compare toric intraocular lens (IOL) implantation with paired opposite clear corneal incisions (OCCIs) for astigmatism correction in patients having cataract surgery. Ophthalmology Service, Donostia Hospital, San Sebastián, Spain. This randomized prospective clinical study comprised eyes with more than 1.00 diopter (D) of preexisting corneal astigmatism. One group had AcrySof toric IOL implantation and the other, paired 2.75 mm/3.20 mm OCCIs in the steep axis with spherical IOL implantation. Uncorrected (UCVA) and best corrected (BCVA) visual acuity, refraction, corneal and total higher-order aberrations (HOAs), photopic and mesopic contrast sensitivity, and toric IOL axis were measured 3 months postoperatively. Forty eyes (40 patients) were evaluated. In the toric group, 95% of eyes achieved 20/40 or better UCVA and 70%, 20/25 or better. In the OCCI group, 80% of eyes achieved 20/40 or better UCVA and 50%, 20/25 or better. All eyes achieved 20/25 or better BCVA. Mean refractive cylinder decreased significantly from preoperatively to postoperatively (-1.75 +/- 0.71 to -0.62 +/- 0.46 D, toric group; -1.61 +/- 0.67 to -0.97 +/- 0.51 D, OCCI group) (P<.01). In the toric group, 95% and 100% of eyes were within +/-0.50 D for J(0) and J(45), respectively. In the OCCI group, the percentages were 70% and 100%, respectively. No significant differences in HOA were found between groups (P>.1). Contrast sensitivity was similar except at the highest spatial frequency, being better in the toric group (P<.01). Toric IOL implantation achieved a slight enhanced effect over OCCIs in treating preexisting astigmatism.

Toric varieties with NC toric actions: NC type IIA geometry

Extending the usual C ∗r actions of toric manifolds by allowing asymmetries between the various C ∗ factors, we build a class of non-commutative (NC) toric varieties V d+1 ( nc) . We construct NC complex d dimension Calabi–Yau manifolds embedded in V d+1 ( nc) by using the algebraic geometry method. Realizations of NC C ∗r toric group are given in presence and absence of quantum symmetries and for both cases of discrete or continuous spectrums. We also derive the constraint equations for NC Calabi–Yau backgrounds M d nc embedded in V d+1 nc and work out their solutions. The latters depend on the Calabi–Yau condition ∑ i q i a =0, q i a being the charges of C ∗r ; but also on the toric data {q i a,ν i A;p I α,ν iA ∗} of the polygons associated to V d+1 . Moreover, we study fractional D-branes at singularities and show that, due to the complete reducibility property of C ∗r group representations, there is an infinite number of fractional D-branes. We also give the generalized Berenstein and Leigh quiver diagrams for discrete and continuous C ∗r representation spectrums. An illustrating example is presented.

NC Calabi–Yau manifolds in toric varieties with NC torus fibration

Using the algebraic geometry method of Berenstein and Leigh (BL) (hep-th/0009209 and hep-th/0105229), and considering singular toric varieties Vd+1 with NC irrational torus fibration, we construct NC extensions Mdnc of complex d dimension Calabi–Yau (CY) manifolds embedded in Vd+1nc. We give realizations of the NC C∗r toric group, derive the constraint equations for NC Calabi–Yau (NCCY) manifolds Mncd embedded in Vd+1nc and work out solutions for their generators. We study fractional D branes at singularities and show that, due to the complete reducibility property of C∗r group representations, there is an infinite number of noncompact fractional branes at fixed points of the NC toric group.

Laser in situ keratomileusis for moderate and high myopia and myopic astigmatism

Objective This study evaluated the predictability, stability, and safety of laser in situ keratomileusis (LASIK) in myopia and myopic astigmatism. Design The study design was a prospective, unmasked, nonrandomized clinical trial. Participants Participating were 25 patients with myopia (37 eyes) with astigmatism of less than 1.00 diopter (D), divided into 3 subgroups (−5.00 to −9.90 D, 8 eyes; −10.00 to −14.90 D, 10 eyes; −15.00 to −29.00 D, 19 eyes), and 37 patients with myopia (56 eyes) with corneal astigmatism of 1.00 to 4.50 D, divided into 3 subgroups (−5.00 to −9.90 D, 12 eyes; −10.00 to −14.90 D, 24 eyes; −15.00 to −29.00 D, 20 eyes). Intervention LASIK was performed using the Automatic Corneal Shaper and the Keracor 116 excimer laser. Main outcome measures Visual acuity, manifest refraction, central corneal islands, ablation decentration, and patient satisfaction were measured. Results At 12 months, predictability, regression between 1 and 12 months, uncorrected visual acuity (UCVA), loss of two or more lines of corrected visual acuity, and patient satisfaction of the spherical (toric) groups are reported. Subgroups −5.00 to −9.90 D: 100% (75%) ±1.00 D; regression less than or equal to 1.00 D in 100% (91.7%); UCVA greater than or equal to 20/40 in 87.5% (70%); none lost two or more lines; 100% (84%) highly satisfied. Subgroups −10.00 to −14.90 D: 60% (78.3%) ±1.00 D; regression less than or equal to 1.00 D in 100% (87%); UCVA greater than or equal to 20/40 in 77.8% (86.4%); 10% (4.3%) lost two lines; 90% (91%) highly satisfied. Subgroups −15.00 to −29.00 D: 38.9% (21.4%) ±1.00 D; regression less than or equal to 1.00 D in 72.2% (64.3%); UCVA greater than or equal to 20/40 in 33.3% (40%); 5.6% (7.1%) lost two lines; 78% (50%) highly satisfied. Differences of predictability and change of manifest refraction between subgroups of −5.00 to −9.90 D and −15.00 to −29.00 D were statistically significant. Central islands (decentrations) were observed in 17% (5.6%) of eyes of the spherical and in 16% (4.1%) of the toric group. Overall, the corneal interface was visible in 8.2%. Conclusions The LASIK method used in this study showed stability of manifest refraction and adequate uncorrected central visual acuity in a large percentage of patients with myopia up to −15.00 D. Corneal stability was not as uniform. Central corneal islands were observed in a sizable minority of patients despite pretreatment. For myopia greater than 15.00 D, accuracy and patient satisfaction were sufficiently poor to advise against using the authors’ treatment technique in these groups. Visually significant microkeratome and laser-related problems were noted in a smaller percentage of patients. Patients with astigmatism correction were less pleased with results than were patients who received spherical corrections.