To assess the agreement of the optical low-coherence reflectometry (OLCR) device LENSTAR LS900 with partial coherence interferometry (PCI) device IOLMaster and applanation and immersion ultrasound biometry.
We conducted the study at the Ophthalmology Clinic, University of Malaya Medical Center, Malaysia. Phakic eyes of 76 consecutive cataract patients were measured using four different methods: IOLMaster, LENSTAR and A-scan applanation and immersion ultrasound biometry. We assessed the method agreement in the LENSTAR-IOLMaster, LENSTAR-applanation, and LENSTAR-immersion comparisons for axial length (AL) and intraocular lens (IOL) power using Bland–Altman plots. For average K, we compared LENSTAR with IOLMaster and the TOPCON KR-8100 autorefractor-keratometer. SRK/T formula was used to compute IOL power, with emmetropia as the target refractive outcome.
For all the variables studied, LENSTAR agreement with IOLMaster is strongest, followed by those with immersion and applanation. For the LENSTAR-IOLMaster comparison, the estimated proportion of differences falling within 0.33 mm from zero AL and within 1D from zero IOL power is 100%. The estimated proportion of differences falling within 0.5 D from zero average K is almost 100% in the LENSTAR-IOLMaster comparison but 88% in the LENSTAR-TOPCON comparison. The proportion of differences falling within 0.10 mm (AL) and within 1D (IOL power) in the LENSTAR-IOLMaster comparison has practically significant discrepancy with that of LENSTAR-applanation and LENSTAR-immersion comparisons.
In phakic eyes of cataract patients, measurements of AL, average K, and IOL power calculated using the SRK/T formula from LENSTAR are biometrically equivalent to those from IOLMaster, but not with those from applanation and immersion ultrasound biometry.
LENSTAR; IOL Master; biometry
To compare AcrySof toric intraocular lens (IOL) and non-toric IOL in patients who had combined 23-gauge microincisional vitrectomy surgery (MIVS) and phacoemulsification for vitreoretinal diseases and cataract with pre-existing corneal astigmatism.
This is a prospective comparative study comprised of 30 patients (30 eyes) who had combined 23-gauge MIVS and phacoemulsification for vitreoretinal diseases and cataract with pre-existing regular corneal astigmatism greater than 1 diopters (D). In all, 15 eyes had AcrySof toric IOL (Alcon Laboratories) and 15 eyes had non-toric IOL (Akreos AO MI60; Bausch & Lomb) implantation. Main outcome measures were uncorrected visual acuity (UCVA), refractive cylinder, surgically induced astigmatism (SIA), and IOL misalignment during 6 months.
The mean UCVA of the toric IOL group was better than the non-toric IOL group at postoperative months 1, 3, and 6 (P<0.001, respectively). The mean absolute residual refractive cylinder of the toric IOL group at postoperative week 1, and months 1, 3, and 6 was less than the non-toric IOL group (P=0.008, <0.001, <0.001, and <0.001, respectively). There was no difference in the mean SIA between the two groups (P>0.05, respectively). The mean toric IOL axis rotation was 3.52±2.75°, which was within 5° in 66.7% of the toric IOL group and within 10° in 100%.
Combined 23-gauge MIVS and phacoemulsification with AcrySof toric IOL implantation is an effective method of correcting vitreoretinal diseases and cataract and pre-existing corneal astigmatism, and the toric IOL showed good rotational stability, even in vitrectomized eyes for 6 months.
toric intraocular lens; corneal astigmatism; IOL rotation; phacovitrectomy
The expectations of post-removal cataract surgery patients are extremely high, and best vision acuity is expected. The best refractive results are influenced by two factors – cataract surgical removal and the corneal astigmatism correction. Currently, the two most often applied corneal astigmatism removal methods are laser surgery and toric intraocular lens implantation, with the latter method being both more stable and more reversible. This study aimed to estimate the surgical astigmatism correction efficiency after AcrySof Toric intraocular lens implantation in patients with corneal astigmatism.
We used the AcrySof Toric IOL 1-part hydrophobic acrylic lenses. The retrospective research covered 30 eyeballs in 28 cataract and corneal astigmatism patients, with the AcrySof Toric lens implanted by one surgeon.
In our test group 92.31% of post-surgical patients (phacoemulsification and toric lenses implantation) gained the best uncorrected visual acuity, range 0.6–1.0; and in 7.69% of patients the acuity was 0.4–0.6. Lens rotation was examined three weeks after the surgical procedure and a 3.24±3.41 degree axial displacement was observed; however, this lens rotation was clinically unimportant.
Based on the analysis of post-surgical results, the corneal astigmatism was 84.2% lower than before the procedure.
We noticed clinically and statistically important vision acuity improvement in the corneal astigmatism patients. The patients’ high satisfaction was conditioned by proper pre-surgery qualification. Astigmatism correction by cataract removal surgery is a safe and effective surgical solution. In the future, we expect the use of toric intraocular lenses will become widespread and significant.
cataract; corneal astigmatism; toric intraocular lenses
We compared visual and refractive outcomes after implantation of Visian toric implantable collamer lenses (toric ICLs) and iris-fixated toric pIOLs (toric Artisans).
Patients and methods
A comparative retrospective analysis was performed. Toric ICLs were implanted into 30 eyes of 18 patients, and toric Artisans into 31 eyes of 22 recipients. We measured the logarithms of the minimum angle of resolution of uncorrected visual acuity (logMAR UCVA), logMAR of best spectacle-corrected corrected VA (logMAR BSCVA), MR, SE, and astigmatism (by the power vector method) before surgery and 1, 3, and 6 months thereafter. Differences between patients receiving each type of lens were compared by using a mixed model of repeated measures.
Visual improvements were evident after operation in both groups. By comparing the attempted to the achieved SE values, we were able to confirm that correction of refractive error was similar in both groups. However, the logMAR UCVA was significantly higher in the toric ICL group at all postoperative time points. Although manifest cylinder power and astigmatism (calculated by using the power vector method) gradually decreased in the toric ICL group, cylinder power 1 month postoperatively increased from −2.62 to −2.75 D; astigmatism was also increased at this time in the toric Artisan group.
The two tested toric pIOLs were similar in terms of the ability to correct refractive error, as assessed 3 months postoperatively. However toric ICLs corrected astigmatism more rapidly and safely. Notably, the large difference in astigmatism level between the two groups 1 month postoperatively indicates that toric ICLs are more effective when used to correct astigmatism.
Visian toric implantable collamer lens; iris-fixated toric phakic intraocular lens; Verisys intraocular lens; phakic intraocular lens; correction of astigmatism
To evaluate the long-term efficacy and rotational stability of the AcrySof toric intraocular lens (IOL) in correcting preoperative astigmatism in cataract patients.
This prospective observational study included 30 eyes from 24 consecutive patients who underwent implantation of an AcrySof toric IOL with micro-coaxial cataract surgery between May 2008 and September 2008. Outcomes of visual acuity, refractive and keratometric astigmatism, and IOL rotation after 1 day, 1 month, 3 months, and long-term (mean, 13.3±5.0 months) follow-up were evaluated.
At final follow-up, 73.3% of eyes showed an uncorrected visual acuity of 20/25 or better. The postoperative keratometric value was not different from the preoperative value; mean refractive astigmatism was reduced to -0.28±0.38 diopter (D) from -1.28±0.48 D. The mean rotation of the toric IOL was 3.45±3.39 degrees at final follow-up. One eye (3.3%) exhibited IOL rotation of 10.3 degrees, the remaining eyes (96.7%) had IOL rotation of less than 10 degrees.
Early postoperative and long-term follow-up showed that implantation of the AcrySof toric IOL is an effective, safe, and predictable method for managing corneal astigmatism in cataract patients.
Astigmatism; Cataract surgery; Toric intraocular lens
To evaluate the accuracy of preoperative keratometers used in cataract surgery with toric intraocular lens (IOL).
Twenty-five eyes received an AcrySof toric IOL implantation. Four different keratometric methods, a manual keratometer, an IOL master, a Pentacam and an auto keratometer, were performed preoperatively in order to evaluate preexisting corneal astigmatism. Differences between the true residual astigmatism and the anticipated residual astigmatism (keratometric error) were compared at one and three months after surgery by using a separate vector analysis to identify the keratometric method that provided the highest accuracy for astigmatism control.
The mean keratomeric error was 0.52 diopters (0.17-1.17) for the manual keratometer, 0.62 (0-1.31) for the IOL master, 0.69 (0.08-1.92) for the Pentacam, and 0.59 (0.08-0.94) for the auto keratometer. The manual keratometer was the most accurate, although there was no significant difference between the keratometers (p > 0.05). All of the keratometers achieved an average keratometric error of less than one diopter.
Manual keratometry was the most accurate of the four methods evaluated, although the other techniques were equally satisfactory in determining corneal astigmatism.
Astigmatism; Cataract; Keratometer; Keratometric error; Toric intraocular lenses
To present clinical results of toric intraocular lens (IOL) implantation for preexisting astigmatism correction and determine the time of any postoperative rotation.
Patients and methods:
Twenty-nine eyes of 19 patients underwent uncomplicated phacoemulsification and were implanted with an Acrysof © toric IOL. Uncorrected visual acuity, residual astigmatism, and postoperative rotation of the IOL were estimated one and six months after the operation.
Uncorrected visual acuity was ≥0.5 in 26 of 29 eyes (89.7%) and ≥0.8 in 19 of 29 patients (65.5%). The mean toric IOL axis rotation was 2.2 ± 1.5° (range 0.6–7.8°) one month postoperation and 2.7 ± 1.5° (range 0.9–8.4°) six months postoperation.
Implantation of one-piece hydrophobic acrylic toric IOLs appears to have acceptable stability, which encourages visual outcome and emerges as an attractive alternative for correction of refractive astigmatism.
astigmatism; cataract; stability; implantation
We report the case of a patient in whom simultaneous toric phakic intraocular lens removal and phacoemulsification with toric intraocular lens implantation were beneficial for reducing pre-existing astigmatism and acquiring good visual outcomes in eyes with implantable collamer lens-induced cataract and astigmatism.
A 53-year-old woman had undergone toric implantable collamer lens implantation three years earlier. After informed consent was obtained, we performed simultaneous toric implantable collamer lens removal and phacoemulsification with toric intraocular lens implantation. Preoperatively, the manifest refraction was 0, -0.5 × 15, with an uncorrected visual acuity of 0.7 and a best spectacle-corrected visual acuity of 0.8. Postoperatively, the manifest refraction was improved to 0, -0.5 × 180, with an uncorrected visual acuity of 1.2 and a best spectacle-corrected visual acuity of 1.5. No vision-threatening complications were observed.
Toric intraocular lens implantation may be a good surgical option for the correction of spherical and cylindrical errors in eyes with implantable collamer lens-induced cataract and astigmatism.
The aim of this study was to evaluate and report the visual, refractive and aberrometric outcomes of cataract surgery with implantation of the new aspheric Tecnis ZCT toric intraocular lens (IOL) in eyes with low to moderate corneal astigmatism.
We conducted a prospective study of 19 consecutive eyes of 17 patients (mean age: 78 years) with a visually significant cataract and moderate corneal astigmatism [higher than 1 diopter (D)] undergoing cataract surgery with implantation of the aspheric Tecnis ZCT toric IOL (Abbott Medical Optics). Visual, refractive and aberrometric changes were evaluated during a 6-month follow-up. Ocular aberrations as well as IOL rotation were evaluated by means of the OPD-Station II (Nidek).
The six-month postoperative spherical equivalent and power vector components of the refractive cylinder were within ±0.50 D in all eyes (100%). Postoperative logMAR uncorrected and corrected distance visual acuities (UDVA/CDVA) were 0.1 (about 20/25) or better in almost all eyes (94.74%). The mean logMAR CDVA improved significantly from 0.41 ± 0.23 to 0.02 ± 0.05 (p < 0.01). No significant changes were found in corneal astigmatism (p = 0.73). The mean IOL rotation was 3.33 ± 1.94°. This parameter did not correlate with higher-order aberrations (r = −0.09, p = 0.73). A significant improvement in the Strehl ratio was also observed (p < 0.01), which was consistent with the significant reduction in higher-order aberrations (p = 0.02).
Cataract surgery with implantation of the aspheric Tecnis ZCT IOL is a predictable and effective procedure for visual rehabilitation in eyes with cataract and low to moderate corneal astigmatism, providing an excellent postoperative ocular optical quality.
Tecnis ZCT; Aspheric toric intraocular lens; Cataract surgery; Higher-order aberrations
To assess the 3-year clinical outcomes of toric phakic intraocular lens (Visian ICL™; STAAR Surgical) implantation for moderate to high myopic astigmatism.
This retrospective study evaluated fifty eyes of 28 patients who underwent toric ICL implantation for the correction of moderate to high myopic astigmatism and who regularly returned for postoperative examination. Before, and 1, 3, and 6 months after, and 1, 2, and 3 years after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery in eyes undergoing toric ICL implantation.
The logarithm of the minimal angle of resolution (LogMAR) uncorrected visual acuity and LogMAR best spectacle-corrected visual acuity were –0.10 (corresponding to Snellen equivalents 20/16) ± 0.16 and –0.20 (corresponding to 20/12.5) ± 0.07, 3 years postoperatively, respectively. The safety and efficacy indices were 1.16 ± 0.20 and 0.94 ± 0.28. At 3 year, 82% and 98% of the eyes were within 0.5 and 1.0 D, respectively, of the targeted correction. Manifest refraction changes of –0.15 ± 0.31 D occurred from 1 month to 3 year. No vision-threatening complications occurred during the observation period.
On the basis of the clinical results of this study, toric ICL implantation was good in all measures of safety, efficacy, predictability, and stability for the correction of moderate to high myopic astigmatism throughout a 3-year observation period.
The purpose of this study was to assess predictability, efficacy, safety and stability in patients who received a toric implantable collamer lens to correct moderate to high myopic astigmatism.
Forty-three eyes of 23 patients underwent implantation of a toric implantable collamer lens (STAAR Surgical Inc) for astigmatism correction. Mean spherical refraction was −4. 98 ± 3.49 diopters (D) (range: 0 to −13 D), and mean cylinder was −2.62 ± 0.97 D (range: −1.00 to −5.00 D). Main outcomes measures evaluated during a 12-month follow-up included uncorrected visual acuity (UCVA), refraction, best-corrected visual acuity (BCVA), vault, and adverse events.
At 12 months the mean Snellen decimal UCVA was 0.87 ± 0.27 and mean BCVA was 0.94 ± 0.21, with an efficacy index of 1.05. More than 60% of the eyes gained ≥1 line of BCVA (17 eyes, safety index of 1.14). The treatment was highly predictable for spherical equivalent (r2 = 0.99) and astigmatic components: J0 (r2 = 0.99) and J45 (r2 = 0.90). The mean spherical equivalent dropped from −7.29 ± 3.4 D to −0.17 ± 0.40 D at 12 months. Of the attempted spherical equivalent, 76.7% of the eyes were within ±0.50 D and 97.7% eyes were within ±1.00 D, respectively. For J0 and J45, 97.7% and 83.7% were within ±0.50 D, respectively.
The results of the present study support the safety, efficacy, and predictability of toric implantable collamer lens implantation to treat moderate to high myopic astigmatism.
phakic intraocular lens; toric implantable collamer lens; astigmatism
This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery.
Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the inserted IOL was at 180° or 90°. For ATR patients, the outcomes were analyzed according to the three types of IOLs.
There was no difference in corneal astigmatism, but WTR patients with a 180° haptic axis of the inserted IOL and ATR patients with a 90° hepatic axis of the inserted IOL had a significant decrease in postoperative refractive astigmatism (p < 0.05). The changes in ATR astigmatism according to the IOL type were more effective in single-piece acrylic IOLs than in the three-piece polymethylmethacrylate haptic IOL group.
Insertion of the IOL at the 180° haptic axis in WTR patients and at 90° in ATR patients during cataract surgery may have an effect in reducing pre-existing astigmatism. This observed effect was not consistent among the different types of IOLs.
Cataract; Clear corneal temporal incision; Haptic axis of inserted intraocular lens; Ocular residual astigmatism
Our purpose was to examine the long-term efficacy of toric intraocular lens (IOL) implantation in cataract patients with high astigmatism due to corneal ectasia, who underwent phacoemulsification cataract surgery. Five eyes of 3 cataract patients with topographically stable keratoconus or pellucid macular degeneration (PMD), in which phacoemulsification with toric IOL implantation was used to correct high astigmatism, are reported. Objective and subjective refraction, visual acuity measurement and corneal topography were performed in all cases before and after cataract surgery. In all cases, there was a significant improvement in visual acuity, as well as refraction, which remained stable over time. Specifically, in subjective refraction, all patients achieved visual acuity from 7/10 to 9/10 with up to −2.50 cyl. Corneal topography also remained stable. Postoperative follow-up was 18–28 months. Cataract surgery with toric IOL implantation seems to be safe and effective in correcting astigmatism and improving visual function in cataract patients with topographically stable keratoconus or PMD.
Phacoemulsification; Keratoconus; Pellucid marginal degeneration; Toric intraocular lens; Intraocular lens; Astigmatism
A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages.
A 44-year-old woman with congenital nystagmus and myopic astigmatism in both eyes who was submitted to phakic intraocular lens (pIOL) implantation.
Full ophthalmologic examination including refractive status, corrected (CDVA) and uncorrected (UCVA) monocular and binocular visual acuities, ocular motility, slit-lamp evaluation, tonometry and fundoscopy before and after implantation of toric pIOLs (Artiflex; Ophtec BV, The Netherlands) in both eyes.
Preoperative logMAR CDVA were 0.699 and 0.420 in the right and left eye, respectively. Three months after surgery, logMAR UCVA were 0.398 and 0.182, reaching binocular logMAR UCVA of 0.132. There were no changes in nystagmus characteristics after surgery.
pIOL implantation may be a safe and suitable treatment to correct high refractive errors in patients with congenital nystagmus. Significant improvement in CDVA and UCVA can be achieved.
Nystagmus; Refractive surgery; Toric phakic intraocular lens
We report the refractive correction of high astigmatism in one eye of a 23-year-old woman following deep anterior lamellar keratoplasty (DALK) using an Artisan iris-fixated, toric, phakic intraocular lens (IOL). One year after implantation, uncorrected and corrected distance visual acuities were both 20/25, refraction was −1.00 D cylinder, and the endothelial cell count was 1827 cells/mm2. Iris-fixated phakic IOLs are not recommended for every postkeratoplasty patient with high refractive error; however, this procedure can offer good outcomes in carefully selected cases of previous DALK.
To evaluate the distance vision of Chinese patients with cataracts and corneal astigmatism after implantation of bilateral AcrySof toric intraocular lens (IOL) versus bilateral AcrySof spherical IOL.
This study randomized 60 patients into equal groups to receive toric IOL or spherical IOL. IOL powers targeting emmetropia were selected for 93% of toric IOL patients and for 90% of spherical IOL patients. Assessments included monocular and binocular distance vision, with and without best correction. Patients also completed surveys about their distance vision.
Preoperatively, the two study groups were similar in age, in distance visual acuity, and in the magnitude of corneal astigmatism. At 6 months postoperative, binocular uncorrected distance vision was 0.06±0.14 logMAR in the AcrySof toric IOL group, significantly better than the 0.14±0.11 logMAR in the spherical IOL group (P<0.05). For eyes with emmetropia as a target, the equivalent of 20/20 uncorrected vision was more likely (P<0.001) in the toric IOL group (36% of eyes) than in the spherical IOL group (4% of eyes). No patients in the emmetropia/toric IOL group used distance glasses, as compared to 52% of patients in the emmetropia/spherical IOL group. All patients were satisfied or highly satisfied. Quality of distance vision was rated higher by toric IOL patients than by spherical IOL patients (P<0.05).
Bilateral AcrySof toric IOL is superior to bilateral spherical IOL in providing uncorrected distance vision to cataract patients with corneal astigmatism.
astigmatism; cataract extraction; lenses, intraocular; pseudophakia
The aim was to evaluate visual and refractive results and complications of intraocular lens (IOL) exchange through a 3.2 mm corneal incision for opacified IOLs.
Materials and Methods:
This retrospective study comprised 33 eyes of 32 patients with IOL opacification requiring an IOL exchange between July 2003 and March 2007. Exchange surgery was performed through a 3.2-mm temporal clear corneal incision followed by implantation of a new foldable hydrophobic IOL. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), topographical astigmatism, and refractive cylinder were evaluated. Surgically induced astigmatism (SIA) was calculated and complications were recorded.
Opacification was observed in 25 eyes (76%) with Aqua-Sense, 3 eyes (9%) with Hydroview, 3 eyes (9%) with MemoryLens IOLs, and 2 eyes (6%) with DgR. The mean follow-up period was 36.54 months. An uneventful IOL exchange was achieved in 18 eyes (55%). Zonular dehiscence occurred in 9 eyes (27%), and posterior capsule tear developed in 4 eyes (12%). The mean preoperative BSCVA (mean ± standard deviation, decimal scale) was 0.13 ± 0.08 (mean: 20/150, range 20/2000 to 20/60) and improved to 0.63 ± 0.18 (mean: 20/32, range 20/60 to 20/20, P < 0.001). The mean SIA was 0.70 D. Seven eyes (21%) had 0.5 D or lower SIA.
IOL exchange is a technically challenging procedure with potential risks of reversing the advantages of a prior small-incision cataract surgery. The use of a small corneal incision for IOL exchange could preserve the advantages of modern phacoemulsification surgery with acceptable SIA related to the procedure.
Intraocular lens opacification; small corneal incision; intraocular lens exchange; postsurgical outcomes
To investigate if the parameters measured routinely prior to cataract surgery with multifocal intraocular lens (IOL) implantation can predict the necessity of additional laser in situ keratomileusis (LASIK) to improve visual outcome.
Records of patients undergoing cataract surgery between January 2008 and December 2009 were reviewed. Individuals satisfied with visual outcome of cataract surgery and not satisfied were grouped (group 1 and 2, respectively). Preoperative data of refractive error, axial length, corneal astigmatism, intraocular pressure, and postoperative uncorrected visual acuity were recorded. Data was available for 62 patients (104 eyes), of which LASIK enhancement was deemed necessary in 21 eyes (20%; group 2). The receiver operator characteristic curves were used to discriminate between the groups and linear regression analysis was performed to predict the postoperative visual outcome.
The astigmatism measured preoperatively using manifest refraction had an accuracy of 64% in discriminating between the groups. Age, spherical component of refraction, axial length, corneal astigmatism, and intraocular pressure were very close to chance prediction 59%, 57%, 56%, 51%, and 51%, respectively. The postoperative uncorrected visual acuity had an accuracy of 79% in discriminating the groups. Individuals with uncorrected visual acuity worse than 20/40 after cataract surgery were most likely to undergo LASIK enhancement; however, approximately 20% of group 2 underwent LASIK enhancement despite having visual acuity of 20/30 or better. When combined, preoperative visual acuity accounted for just 7% of variance in postoperative uncorrected visual acuity.
Requirement of LASIK enhancement after cataract surgery with multifocal IOL implant is complex in nature, and parameters routinely measured before surgery cannot successfully identify the group requiring LASIK enhancement or predict postoperative uncorrected visual acuity.
refractive error; axial length; corneal astigmatism; intraocular pressure; uncorrected visual acuity; visual outcome; multivariate analysis; LASIK enhancement
A 56-year-old Caucasian male was referred to the corneal service for the management of post penetrating keratoplasty (PK) astigmatism in his right eye. He had also previously undergone trabeculectomy and cataract surgery in the same eye. Corneal topography showed high postoperative astigmatism of 8.74 dioptres. He was intolerant to contact lens wear and could not tolerate spectacle correction due to high anisometropia. He proceeded to undergo a secondary ‘piggyback’ toric intraocular lens (IOL) insertion procedure with an improvement in his best corrected visual acuity to 6/9. With the decrease in anisometropia he was able to tolerate a full spectacle correction. We report the use of a new injectable sulcus fixated toric piggyback IOL for the correction of post PK astigmatism in a pseudophakic eye. To the best of our knowledge this is the first report on the use of this new ‘add on’ IOL for this clinical condition.
We report the case of a 37-year-old man with a high myopic keratoconus eye that was treated with a posterior chamber toric implantable collamer lens (ICL) in Korea. The patient had a history of contact lens intolerance and did not want to have a corneal transplantation. His uncorrected visual acuity (UCVA) and best spectacle corrected visual acuity were 0.02 and 0.4 in the left eye, respectively. Preoperatively, the manifest refraction was -12.0 -3.5 × 30A. Postoperatively, the manifest refraction was -1.75 × 180A. UCVA improved markedly after implantation. No intraoperative or postoperative complications were observed during 20 months of follow-up. Toric ICL implantation may be a possible alternative surgical option for the visual rehabilitation of high myopic astigmatism in keratoconus patients with rigid gas permeable contact lens intolerance and in patients who do not want to get a corneal transplant.
Astigmatism; High myopia; Keratoconus; Toric implantable collamer lens
Cataracts are a common and significant cause of visual impairment globally. We aimed to evaluate uncorrected distance visual acuity (UDVA) as an outcome in treating astigmatic cataract patients to assist clinicians or ophthalmologists in their decision making process regarding available interventions.
Medline, Embase and Evidence Based Reviews were systematically reviewed to identify relevant studies reporting changes in UDVA, UIVA and UNVA after cataract surgery in presbyopic patients. Strict inclusion/exclusion criteria were used to exclude any non-relevant studies. Relevant outcomes (UDVA, UIVA and UNVA) were identified from the studies retrieved through the systematic review process.
The systematic review identified 11 studies which reported UCVA. All 11 studies reported UDVA. Four brands of toric intraocular lenses (IOLs) were reported in these studies. All studies identified in the literature search reported improvements in UDVA following surgical implant of a toric IOL. The largest improvements in VA were reported using the Human Optics MicroSil toric IOL (0.74 LogMAR, UDVA) and the smallest improvements were also reported using the Human Optics MicroSil toric IOL (0.23 LogMAR, UDVA) in a different study.
The results of this systematic review showed the aggregate of studies reporting a beneficial increase in UDVA with the use of toric IOLs in cataract patients with astigmatism.
Astigmatism; Toric; Intraocular lenses; Uncorrected distance visual acuity; Uncorrected near visual acuity; Visual acuity; Systematic review; Cataracts
AIM—Some surgeons consider hand held surgical keratometers unreliable. This may be due to incorrect use through not realising that the distance that the keratometer is held from the cornea influences the shape of the image. When a keratometer is held closer to the astigmatic cornea, the elliptical image will appear more circular, particularly for larger degrees of astigmatism. However, the keratoscopic astigmatic ruler (KAR) has design features that correct the hitherto unrecognised problems with the use of a hand held keratometer. This study assesses the reliability and accuracy of measurement of astigmatism using the KAR.
METHODS—The KAR and the Bausch & Lomb keratometer (B&L) were compared using six back surface toric cut contact lens blanks representing 1 to 6 dioptres of astigmatism. Two observers (one experienced in the use of the keratometers, the other a novice) took eight randomly repeated "masked" measurements of each lens blank with the KAR and four measurements with the B&L in a similar fashion.
RESULTS—There was no difference between the measurements with either instrument by each of the observers (p=0.95, ANOVA). The standard error of measurement for the KAR was 0.59 D, for the B&L, 0.31 D. The intraclass correlation coefficient of reliability for the KAR was 0.90 and for the B&L it was 0.97. The coefficient of repeatability for the KAR was plus or minus 0.83 D, and for the B&L plus or minus 0.77 D. The interobserver reliability for the KAR was 0.898, and for the B&L, 0.975.
CONCLUSION—These results suggest that the KAR has good reliability and reproducibility and compares favourably with the B&L keratometer. Inexperience with use does not affect reliability.
Keywords: keratometry; calibration
Keratoconus is a progressive non-inflammatory thinning of the cornea that induces myopia and irregular astigmatism and decreases the quality of vision due to monocular diplopia, halos, or ghost images. Keratoconus patients unfit for corneal procedures and intolerant to refractive correction by spectacles or contact lenses have been implanted toric posterior chamber phakic intraocular lenses (PC pIOLs) alone or combined with other surgical procedures to correct the refractive errors associated with keratoconus as an off label procedure with special informed consent from the patients. Several reports attest to the safety and efficacy of the procedure, though the associated corneal higher order aberrations would have an impact on the final visual quality.
Implantable collamer lens; intra corneal ring implants; keratoconous; toric implantable collamer lens
To evaluate success rates in the correction of astigmatism with toric and spherical soft contact lens fitting.
30 patients with soft toric lenses having more than 1.25 D of corneal astigmatism (25 eyes; Group A) or having 0.75–1.25 D of corneal astigmatism (22 eyes; Group B) and 30 patients with soft spheric lenses having 0.75–1.25 D of corneal astigmatism (28 eyes; Group C) or less than 0.75 D of corneal astigmatism (23 eyes; Group D) were included in the study. Corrected and uncorrected monocular visual acuity measurement with logMAR, biomicroscopic properties, autorefractometry and corneal topography were performed for all patients immediately before and at least 20 minutes after the application of contact lenses. Success of contact lens fitting was evaluated by three parameters: astigmatic neutralization, visual success, and retinal deviation.
After soft toric lens application, spheric dioptres, cylindric and keratometric astigmatism, and retinal deviation decreased significantly in Groups A and B (P < 0.05). In Group C, spheric dioptres and retinal deviation decreased (P < 0.05), while cylindric and keratometric astigmatism did not change significantly (P > 0.05). In Group D, spheric dioptres, retinal deviation, and cylindric astigmatism decreased (P < 0.05). Keratometric astigmatism did not change significantly (P > 0.05) and astigmatic neutralization even increased.
Visual acuity and residual spherical equivalent refraction remained between tolerable limits with the use of toric and spheric contact lenses. Spherical lenses failed to mask corneal toricity during topography, while toric lenses caused central neutralization and decrease in corneal cylinder in low and moderate astigmatic eyes.
astigmatism; soft toric lenses; soft spheric lenses; spherical equivalent refraction; surface topography