Angle-supported phakic IOLs withdrawn from the French market
OSN SuperSite Top Story 6/7/2007
Angle-supported phakic IOLs withdrawn from the French market
Angle-supported phakic IOLs will no longer be sold and implanted in France due to an alarming amount of endothelial cell loss found in a significant number of patients 2 to 3 years after implantation.
Manufacturers IOLTech/Carl Zeiss Meditec and Corneal, in accordance with the French Agency for the Sanitary Safety of Health Products (AFSSAPS), ordered the withdrawal from the market of the Vivarte and NewLife phakic IOLs (both IOLTech/Carl Zeiss Meditec) in January and the Icare lens (Cornéal) in March.
An alert was first raised in February 2006, when a warning note was distributed by the manufacturers of the NewLife and Vivarte presbyopic IOLs to all ophthalmology departments. The document mentioned cases of "explantation of these lenses due to endothelial cell loss, occurring 2 to 3 years after implantation." It also announced a retrospective study to determine the incidence and causes of this late complication.
Commercialization of the NewLife and Vivarte presbyopic lenses was temporarily suspended while the manufacturers waited for the study results. In the meantime, yearly examinations of the corneal endothelium and endothelial cell counts were recommended for all patients who had been implanted. Surgeons were also required to report all cases of endothelial cell loss to the authorities.
Iatrogenic ring scotoma after LASIK
Journal of Cataract and Refractive Surgery
October 2002 Volume 28, Number 10
Sandra M. Brown, MD, Jose Morales, MD
A 37-year-old ophthalmologist had bilateral simultaneous laser in situ keratomileusis (LASIK) for moderate myopia with astigmatism using the Alcon Summit LADARVision laser; an ablation zone of 5.5 mm was used. Five months after surgery, the uncorrected visual acuity was 20/20 and 20/25 but despite regular corneal topographies, the patient experienced prominent ghost images under photopic and scotopic conditions. To elucidate the nature of the problem, automated static perimetry was performed, which revealed a significant depression between 10 degrees and 30 degrees compared with a baseline study obtained 3 years earlier. The patient started brimonidine 0.2% 1 drop in both eyes every morning, which caused 1.5 to 2.0 mm of pupillary miosis (tonic pupil size 3.0 to 4.0 mm in dim light) and eradicated the ghost images. Repeat perimetry showed significant improvement in all indices. The mechanism of improvement is unclear but may be due to elimination of light scatter from the transition zone between the ablated and unablated cornea. The issue of perimetric changes after refractive surgery deserves more attention; postoperative testing may be indicated for patients in whom the ablation zone diameter is close to the mesopic or scotopic pupil size to provide an accurate lifetime baseline visual field.
Accurate intraocular lens power calculation after myopic LASIK, bypassing corneal power
J Cataract Refract Surg. 2006 Mar;32(3):425-9
Walter KA, Gagnon MR, Hoopes PC Jr, Dickinson PJ.
PURPOSE: To describe a novel method for calculating intraocular lens (IOL) power after myopic laser in situ keratomileusis (LASIK) without using the inaccuracies of the post-LASIK corneal power.
SETTING: Department of Ophthalmology, Wake Forest University Eye Center, Wake Forest University School of Medicine, Winston Salem, North Carolina, USA.
METHODS: This retrospective chart review comprised 9 eyes of 9 patients who had phacoemulsification after LASIK using our method for IOL calculation. This new method assumes the patient never had myopic LASIK to calculate IOL power and then targets the IOL at the pre-LASIK amount of myopia. The pre-LASIK keratometry values, pre-LASIK manifest refraction, and the current axial length are placed in the Holladay formula, bypassing the post-LASIK corneal power. In theory, assuming that the patient had satisfactory LASIK results, the correct IOL can then be determined.
RESULTS: The mean spherical equivalent postoperative refraction was +0.03 diopter (D) +/- 0.42 (SD) (range -0.625 to +0.75 D). In all 9 eyes, our method consistently chose the most accurate and precise IOL compared with other methods.
CONCLUSIONS: The new method of calculating IOL power after LASIK provided excellent results and the most accurate and precise results to date.
Intrastromal corneal ring implantation for the correction of myopia: 12-month follow-up
J Cataract Refract Surg 2003; 29:322–328
Magda Rau, MD, Dieter Dausch, MD
Purpose: To evaluate the efficacy, predictability, and stability of refraction obtained after intrastromal corneal ring segment (ICRS) implantation for low to moderate myopia
Setting: Single-center clinical practice.
Methods: In this prospective 2-surgeon study, 9 patients (15 eyes) with low to moderate myopia were recruited to receive ICRS implants.
Results: At 1 day, 10 of the 15 eyes had an uncorrected visual acuity (UCVA) of 20/40 or better. At 12 months, all eyes had this UCVA and 66.6% had 20/25 or better. The mean manifest refraction stabilized after the first week at <−0.5 diopter (D). At 12 months, all eyes were within ±1.0 D of the intended manifest refraction; 67% were within ±0.5 D. Sixty percent of eyes had no change from the preoperative best corrected visual acuity; 13.3% improved by 1 line, and 26.6% lost 1 line. The postoperative complications included lamellar channel deposits (n = 12), ICRS dislocation (n = 2), corneal infiltrates (n = 2), bleeding in the positioning ring hole (n = 1), 0.3 mm segment decentration (n = 1), and prolonged wound healing (n = 1).
Conclusions: Intrastromal corneal ring segment implantation for the correction of low to moderate myopia afforded good visual recovery and efficacy similar to that with laser in situ keratomileusis and superior to that with photorefractive keratectomy. However, light or blunt trauma and insufficient hygiene can have serious consequences and there is the potential for induced astigmatism. Corneal infiltrates can occur and must be treated immediately. The ring implantation technique is demanding. Advantages of ICRS implantation include rapid and stable visual recovery as well as reversibility.
Preventing IOP increase after phacoemulsification and the role of perioperative apraclonidine
J Cataract Refract Surg 2002; 28:2177–2180
Savitha R. Kasetti, FRCSEd, Shrivatsa P. Desai, FRCOphth, Subramaniam Sivakumar, FRCSEd, Palaniswamy Sunderraj, FRCOphth, FRCSEd
Purpose: To evaluate the effectiveness of prophylactic topical apraclonidine 1% in preventing an intraocular pressure (IOP) rise in the early period after uneventful phacoemulsification with intraocular lens (IOL) implantation. Setting: District general hospital, United Kingdom.
Methods: In this prospective masked randomized trial, 61 patients had elective, routine, corneal tunnel, sutureless phacoemulsification with in-the-bag foldable IOL implantation. A single surgeon operated on all the patients. Patients were randomized to receive topical apraclonidine 1% eyedrops (n = 31) or artificial tears (control group, n = 30) 1 hour preoperatively and at the end of the surgery. An observer masked to the perioperative drops used measured the IOP preoperatively and 3 to 6 hours and 16 to 24 hours postoperatively. The primary outcome was the change in IOP between the baseline and the 2 postoperative intervals. The IOP changes within and between the groups were analyzed using the t test and chi-square test.
Results: The changes between the postoperative and preoperative IOPs in the study groups were statistically significant (apraclonidine, P = 0.018 and P = 0.007, respectively; artificial tears, P = 0.028 and P = 0.023, respectively; paired t test). There was no significant difference in the postoperative IOP between the apraclonidine and control groups 3 to 6 hours and 16 to 24 hours postoperatively (P = 0.717 and P = 0.497, respectively; independent t test). The mean difference was 0.2 mm Hg (95% confidence interval [CI], −3.4 to 3.1) in the apraclonidine group and 2.2 mm Hg (95% CI, −2.5 to 7.0) in the control group. In each group, a few patients had an IOP greater than 30 mm Hg in the first 24 hours.
Conclusion: Prophylactic topical perioperative apraclonidine 1% did not cause a significant reduction in the postoperative IOP when compared with a control group.
Pupil diameter changes and reaction after posterior chamber phakic intraocular lens implantation
J Cataract Refract Surg 2002; 28:2170–2172
Richard J. Keuch, MD, Heinrich Bleckmann, MD
Purpose: To compare the different aspects of pupil constriction before and after the implantation of an implantable contact lens (ICL).
Setting: Augenabteilung der Schlosspark-Klinik Berlin, Berlin, Germany.
Methods: This study comprised 15 myopic and 9 hyperopic eyes that were evaluated before and after the implantation of an ICL using a compact integrated pupillograph (CIP, AMTech) under standardized conditions. The preoperative and postoperative pupil diameters, rate and latency of the pupil reaction, and amplitude of constriction were compared. Results: The latency and the duration of pupil constriction were significantly prolonged after ICL implantation. The rate of pupil contraction and redilation, the pupil diameter, and the amplitude of pupil constriction were reduced after ICL implantation.
Conclusion: The pupil reaction after implantation of a phakic posterior chamber ICL was slower. The postoperative pupil diameter was smaller, and the amplitude of constriction was reduced. The changes have not proved to be clinically significant to date.
Change in IOP measurements after LASIK the effect of the refractive correction and the lamellar flap
Ophthalmology. 2005 Jun;112(6):1009-16.
Chang DH, Stulting RD. Department of Ophthalmology, Emory University School of Medicine, Atlanta, Georgia, USA.
OBJECTIVE: To study the relationship between intraocular pressure (IOP) readings after LASIK and the amount of refractive correction.
DESIGN: Retrospective noninterventional case series.
PARTICIPANTS: Patients receiving primary LASIK for myopia and myopic astigmatism.
METHODS: A database of preoperative, intraoperative, and 3-month postoperative data for 8113 consecutive eyes that underwent primary myopic and myopic astigmatic LASIK was retrospectively reviewed. Linear regression analysis of measured IOP change as a function of refractive change was then performed. Age and preoperative keratometry were also reviewed by multiple regression.
MAIN OUTCOME MEASURES: Best-fit curve relating change in measured IOP to refractive change.
RESULTS: The mean spherical equivalent of the refractive change was -4.98+/-2.64 diopters (mean +/- standard deviation). The mean decrease in measured IOP was 2.0+/-3.3 mmHg. Linear regression analysis revealed a decrease of 0.12 mmHg of measured IOP per diopter of refractive change (95% confidence interval [CI], 0.09-0.15, R(2) = 0.009, P<0.001). Extrapolation of the data to a theoretical correction of zero diopters revealed a decrease of 1.36 mmHg (95% CI, 1.20-1.51, P<0.001), suggesting a component of measured IOP change that is independent of laser ablation.
CONCLUSIONS: The reduction of IOP readings after corneal refractive surgery is a linear function of the amount of refractive correction, with an additional constant reduction that is probably related to the lamellar corneal flap. These data suggest that the lamellar corneal flap makes no contribution to the load-bearing characteristics of the post-LASIK cornea.
A Correction Formula for the Real IOP After LASIK for the Correction of Myopic Astigmatism
JOURNAL OF REFRACTIVE SURGERY
Vol. 22 No. 3 March 2006
Markus Kohlhaas, MD; Eberhard Spoerl, PhD; Andreas G. Boehm, MD; Katharina Pollack, MD
PURPOSE: To create a correction formula to determine the real intraocular pressure (IOP) after LASIK considering the altered corneal thickness, corneal curvature, and corneal stability.
METHODS: This prospective clinical trial comprised 101 eyes of 59 patients (34 women and 25 men) that underwent LASIK with a mean preoperative spherical equivalent refraction of –6.3±2.17 diopters (D) (–3.0 to –11.5 D). Mean patient age was 32±9 years. Preoperatively and 6 months postoperatively, IOP (by Goldmann applanation tonometry), keratometry (by topography), and central corneal thickness (CCT) (by ultrasound pachymetry) were evaluated. These parameters were measured in all patients between 8 and 11 o’clock in the morning.
RESULTS: Due to the LASIK procedure, IOP was reduced from 16.5±2.1 mmHg (range: 12 to 22 mmHg) to 12.9±1.9 mmHg (range: 8 to 16 mmHg). Multiple linear regression analysis of the IOP values before and after LASIK showed a significant correlation between the measured IOP and CCT and keratometry values (R2=0.631; P<.001). After LASIK, the biomechanical bending strength of the cornea is reduced by the cut so that the measured IOP must be additionally corrected by 0.75 mmHg. An equation containing all three changes is given: IOP (real) = IOP (measured) + (540-CCT)/71 + (43 - K-value)/2.7 + 0.75 mmHg.
CONCLUSIONS: Intraocular pressure measurements after LASIK for the correction of myopia are inaccurate as a consequence of changes in CCT, corneal curvature, and corneal flap stability. After LASIK, the measured IOP should be corrected to avoid false low IOP applanation readings. [J Refract Surg. 2006;22:263-267.]
A predictive model for postoperative intraocular pressure among patients undergoing LASIK
Yang CC, Wang IJ, Chang YC, Lin LL, Chen TH.
Department of Ophthalmology, Taipei County San-Chung Hospital, Taipei, Taiwan.
PURPOSE: The aim of this study was to develop a predictive model based on preoperative variables for estimating postoperative intraocular pressure (IOP) of those eyes undergoing LASIK surgery, to predict the amount of underestimated IOP after LASIK for myopia and myopic astigmatism.
DESIGN: Pretest-post-test longitudinal study.
METHODS: Both eyes of 193 eligible subjects who underwent LASIK procedures at the Department of Ophthalmology, National Taiwan University Hospital, from July 2000 to December 2002 for myopia and myopic astigmatism were identified to build up the predictive models. IOPs were measured with noncontact air-puff tonometry. Information on age, gender, preoperative central corneal thickness (CCT), preoperative central corneal curvature (CCK), preoperative spherical equivalent refractive error, and ablation depth was collected and applied for predicting postoperative IOP after LASIK based on linear mixed model.
RESULTS: Significant predictors for postoperative IOP after myopic LASIK procedures included age, gender, preoperative IOP, ablation depth, preoperative CCT, and preoperative spherical equivalent refractive errors. The linear mixed model, taking into account these significant preoperative correlates and the correlation of IOPs between both eyes of the same patient, explained 91% of the variation of postoperative IOP.
CONCLUSIONS: A statistical model was developed for predicting the amount of underestimated IOP after LASIK for myopia and myopic astigmatism, which is of clinical importance to uncover ocular hypertension among patients whose information on postoperative IOP immediately after LASIK is not available.
Effect of microkeratome suction during LASIK on ocular structures
Ophthalmology. 2005 Apr;112(4):645-9.
Mirshahi A, Kohnen T. Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt am Main, Germany.
PURPOSE: To study the effect of microkeratome suction on ocular structures during LASIK. DESIGN: Observational, prospective case series.
PARTICIPANTS: Twenty-one eyes of 11 patients with myopia or astigmatic myopia (8 females, 3 males) were included. The mean patient age was 36.3 years (median, 37 years; range, 24-48 years), and the mean spherical equivalent was -5.03 diopters (D) (median, -4.63 D; range, -2.38 to -8.38 D).
METHODS: We performed preoperative and intraoperative A-scan ultrasonography during application of suction using the Hansatome microkeratome (Bausch & Lomb Surgical, Munich, Germany) to create corneal flaps during LASIK. We also performed preoperative and postoperative B-scan ultrasonography of the posterior ocular segment with special attention to the presence and size of posterior vitreous detachment (PVD).
MAIN OUTCOME MEASURES: We measured changes in the axial length, anterior chamber depth, lens thickness, and vitreous distance (distance from the posterior lens capsule to the posterior pole) during application of the microkeratome suction ring and recorded new occurrences of or increases in the size of the PVD after surgery.
RESULTS: The lens thickness decreased (mean change, -0.20 mm; P = 0.001; 95% confidence interval [CI], -0.11 to -0.30) in 18 eyes during application of the suction ring. The vitreous distance increased (mean change, 0.20 mm; P = 0.004; 95% CI, 0.08-0.32) in 16 eyes. No statistically significant changes were found in the anterior chamber depth (P = 0.75) or axial length (P = 0.51). After surgery, 3 of 14 eyes (21.4%) experienced PVD that did not have echographic signs of PVD before surgery. Of 7 eyes with preoperative PVD, the PVD enlarged in 1 eye (14.3%).
CONCLUSIONS: During application of microkeratome suction, the lens thickness decreases, whereas the vitreous distance increases, suggesting anterior traction on the posterior segment. The relationship between the observed PVD and LASIK merits further investigation.
The AS biometry technique-A novel technique to aid accurate intraocular lens power calculation after
...corneal laser refractive surgery.
Cont Lens Anterior Eye. 2006 Apr 4;
The AS biometry technique-A novel technique to aid accurate intraocular lens power calculation after corneal laser refractive surgery.
Sambare C, Naroo S, Shah S, Sharma A. The Ophthalmic Department, Kempston Road, Bedford Hospital, Bedford MK42 9DJ, UK.
Intraocular lens power (IOL) calculation for cataract surgery has been shown to be inaccurate after photorefractive keratectomy (PRK), laser-assisted subepithelial keratectomy (LASEK) and laser in situ keratomileusis (LASIK). Many techniques exist to calculate corneal power with varying results and require the clinician to be aware of the pitfalls of IOL power calculation in post-refractive eyes. The AS biometry method proposed here is a simple method which does not rely on the calculation of corneal power. This new method is compared to the current gold standard the clinical history method (CHM). Twenty-nine eyes of 15 patients had routine biometry prior to LASIK, LASEK or PRK. The range of pre-operative spherical equivalent refractive error was -5.37 to +4.00diopters. The post-operative refraction was measured at 3-6 months. The IOL power calculation was calculated using the AS biometry method and the CHM. The two methods were compared using the Student's paired t-test and the Bland Altman technique. There was no statistical difference between the AS biometry method and the CHM. The paired Student's t-test comparing the AS biometry method and the CHM showed no statistical difference, t=0.33 with a p-value of 0.75, at a 95% confidence interval. The authors conclude that the AS biometry technique is as accurate as the CHM. The former is a simpler method which avoids many of the pitfalls and confounding factors involved in IOL power calculation following corneal excimer laser surgery. However, like the CHM it requires measurements prior to laser surgery.
Contact Wearers, Beware!
Dr. William Trattler asks that patients lobby against contact lenses
"LASIK question" Posted by William B. Trattler, MD
Excerpt: "My last comment is to inform some of the LASIK bashers that one of the alternatives to LASIK - contact lenses - can also be a serious health risk to the eye. As a cornea specialist, I take care of contact lens-associated corneal infections on a daily basis. Many patients in the United States go blind every day from the use of contact lenses (especially when patients sleep in them). So please also lobby against the use of contact lenses if you want to reduce the risk of eye injury in the U.S.".
Bill Trattler, MD
Contact lens overrefraction variability in corneal power estimation after refractive surgery
J Cataract Refract Surg. 2005 Dec;31(12):2287-92.
Joslin CE, Koster J, Tu EY. From the Department of Ophthalmology and Visual Sciences (Joslin, Koster, Tu) and School of Public Health (Joslin), Division of Epidemiology and Biostatistics, University of Illinois, Chicago, Illinois, USA.
PURPOSE: To evaluate the accuracy and precision of the contact lens overrefraction (CLO) method in determining corneal refractive power in post-refractive-surgery eyes.
SETTING: Refractive Surgery Service and Contact Lens Service, University of Illinois, Chicago, Illinois, USA.
METHODS: Fourteen eyes of 7 subjects who had a single myopic laser in situ keratomileusis procedure within 12 months with refractive stability were included in this prospective case series. The CLO method was compared with the historical method of predicting the corneal power using 4 different lens fitting strategies and 3 refractive pupil scan sizes (3 mm, 5 mm, and total pupil). Rigid lenses included 3 9.0 mm overall diameter lenses fit flat, steep, and an average of the 2, and a 15.0 mm diameter lens steep fit. Cycloplegic CLO was performed using the autorefractor function of the Nidek OPD-Scan ARK-10000. Results with each strategy were compared with the corneal power estimated with the historical method. The bias (mean of the difference), 95% limits of agreement, and difference versus mean plots for each strategy are presented.
RESULTS: In each subject, the CLO-estimated corneal power varied based on lens fit. On average, the bias between CLO and historical methods ranged from -0.38 to +2.42 diopters (D) and was significantly different from 0 in all but 3 strategies. Substantial variability in precision existed between fitting strategies, with the range of the 95% limits of agreement approximating 0.50 D in 2 strategies and 2.59 D in the worst-case scenario. The least precise fitting strategy was use of flat-fitting 9.0 mm diameter lenses.
CONCLUSIONS: The accuracy and precision of the CLO method of estimating corneal power in post-refractive-surgery eyes was highly variable on the basis of how rigid lense were fit. One of the most commonly used fitting strategies in clinical practice-flat-fitting a 9.0 diameter lens-resulted in the poorest accuracy and precision. Results also suggest use of large-diameter lenses may improve outcomes.
Contact lens fitting post-refractive surgery
Ophthalmic Physiol Opt. 2006 Mar;26(2):212.
Department of Optometry, Royal Berkshire Hospital, London Road, Reading RG1 5AN, UK.
Purpose: A number of patients who had undergone refractive surgery still required contact lens fitting. Indications for fitting included the correction of residual ametropia, anisometropia, and regular and irregular astigmatism. In some cases, a post-treatment therapeutic bandage soft contact lens was used to protect the treated eye and to promote regular epithelial healing. Lens fitting was reviewed to give recommendations for problem solving and fitting this category of patient.
Methods: Before lens fitting, a full history and symptoms and refraction were obtained. The practitioner explained the results of the refractive surgery, advised on advantages and limitations of lens wear and described the choices available. The fitting procedure involved anterior segment assessment and measurement of ocular parameters. Several steps were often required to achieve a successful lens fit and tolerance. Three main categories of refractive surgery were outlined: (1) Internal procedure, e.g. implantation of an intra-ocular lens or a special soft lens draped over the crystalline lens. (2) Corneal incision, e.g. penetrating and lamellar keratoplasty, radial keratotomy (RK), transverse incision for astigmatism reduction, and stromal lens insertion. (3) Laser techniques, e.g. PRK, LASIK, LASEK, Holmium laser and thermo-keratoplasty.
Results: Contact lenses were fitted aiming to cause least disturbance to the cornea which had already been compromised by previous surgery. Good oxygen transmission, surface wettability and lens design were important features. A rigid gas permeable (RGP) lens could support and protect the cornea, provide a corrective tear lens between the lens and the new corneal contour, and help to stabilise visual acuity. Often a RGP lens of large diameter was required to bridge over the contours of the central cornea region and assist lens centration. Good visual acuity was usually achieved unless residual stromal haze prohibited this. A soft lens draped over the cornea gave good comfort and lens centration. However, it was less effective on irregular astigmatism and led to variable visual acuity on RK or over wide laser ablation zones.
Conclusion: Fitting the post-refractive surgery cornea was challenging. Extra time and assessment were recommended as the new corneal topography could lead to problems with contact lens centration and stability of visual acuity. Waiting 3 months post-treatment to allow the corneal topography to stabilise before commencing fitting is particularly recommended for RK and PRK. Lens aftercare included management of the patients' high expectations.