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ESCRS Endophthalmitis Study results highlight annual meeting in London
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LONDON — Final results of a multicenter European study confirm that intracameral antibiotics can play a role in preventing endophthalmitis after cataract surgery, according to Peter Barry, FRCS, the chairman of the study.
Dr. Barry described the results of the European Society of Cataract and Refractive Surgeons Endophthalmitis Study in delivering the 2006 Ridley Medal Lecture at the ESCRS meeting here.
“Cefuroxime injection lowers the chances of bacterial contamination by a factor of five. This means that the risk rate is reduced to less than five in 10,000 cases,” he said.
Cefuroxime seems to be particularly protective against streptococci, which can cause severe blinding infections, Dr. Barry said. No cases of streptococcal infection were seen in patients who received cefuroxime, he said. Cefuroxime is not approved for intraocular use, Dr. Barry noted. For the study, investigators were required to obtain special exemptions for its use. Most countries allow physicians to use cefuroxime off-license, although physicians are responsible for the ramifications, he said.
 Peter Barry, FRCS, presented results of the ESCRS Endophthalmitis Study. |
Cefuroxime is not approved for intraocular use, Dr. Barry noted. For the study, investigators were required to obtain special exemptions for its use. Most countries allow physicians to use cefuroxime off-license, although physicians are responsible for the ramifications, he said.
“In practical terms, taking 750 mg of cefuroxime powder and diluting it by yourself to a concentration of 1 mg [per] 0.1 mL exposes you to all of the risks of a kitchen pharmacy, with errors in dilution, a possible induction of toxic anterior segment syndromes and the frightening possibility of contamination, for example with Pseudomonas, against which cefuroxime is not effective,” Dr. Barry said.
Because of this, Dr. Barry appealed to the pharmaceutical industry to provide ophthalmologists with single sterile unit doses of cefuroxime for use in the millions of cataract procedures performed annually worldwide.
In addition to the beneficial role of cefuroxime, the study established the crucial contribution of a polymerase chain reaction in proving infection in suspected cases. It also established the incidence of endophthalmitis risk factors other than non-use of cefuroxime injection. In particular, silicone IOLs as opposed to acrylic lenses, as well as the use of clear corneal incisions rather than scleral tunnel incisions, were found to significantly increase the likelihood of experiencing such infections.
The ESCRS Endophthalmitis Study involved nearly 16,000 patients examined in 24 centers in nine European countries, making it “the largest study of an antibiotic in the history of medicine,” Dr. Barry said.
Below are additional highlights from the ESCRS meeting as first published on the OSN SuperSite. Look for in-depth coverage of selected items in upcoming issues.
Cataract Surgery
Cataract surgery in patients with ocular surface disease requires careful approach
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![Thomas F. Neuhann, MD [photo]](/images/osnea/200610/neuhann.jpg "Thomas F. Neuhann, MD [photo]")
When considering cataract surgery in patients with ocular surface diseases such as corneal scars, conjunctivalization and limbal stem cell deficiency, surgeons should first determine whether surgery is warranted and if it will provide a meaningful improvement, according to Thomas F. Neuhann, MD.
If there are sufficient indications for proceeding with cataract surgery, the surgeon must also be prepared to handle specific preoperative, intraoperative and postoperative problems, Dr. Neuhann said.
“In many cases, the cataract behind those surface diseases is not the primary problem of the patient,” he said. “By doing surgery, you may elicit more problems than you actually solve.”
Preoperative problems are mainly related to IOL calculation, he said. Lubrication and multiple readings can help obtain usable keratometry data. In more severe cases, data from the healthy contralateral eye can instead be used to make an estimate. But if the second eye is just as bad, the only option is “an educated guess,” Dr. Neuhann said.
Intraoperatively, problems are due to poor visualization, which “is critical in performing capsulorrhexis,” he said.
To aid visualization, Dr. Neuhann said the use of trypan blue can be helpful and that it is important to proceed carefully with surgery. “It is better to invest some extra time at this stage because an intact [continuous curvilinear capsulorrhexis] makes surgery a lot easier,” he said.
Lifting the nucleus more than usual may also improve visualization. But when doing this, surgeons must protect the endothelium with generous dispersive viscoelastics, he said. A gentle approach is also needed for capsular polishing, he added.
Postoperatively, Dr. Neuhann recommended generous lubrication with preservative-free eye drops for all patients, calling it “even more important than aggressive anti-inflammatory therapy.”
“Don’t forget that, postoperatively, you have to compromise between the conflicting therapeutic goals of the ocular surface disease … and the requirements of postoperative inflammation suppression. … Steroids slow down re-epithelialization, but NSAIDs may induce corneal melt in these patients,” he said.
“If you use drops, follow those patients frequently … and consider subconjunctival injection as a possible alternative,” Dr. Neuhann said.
C-Flex IOL has low PCO rate at 2 years
A square-edged hydrophilic acrylic IOL shows good functional results, with a low incidence of posterior capsule opacification at 2 years’ follow-up, according to Yutaro Nishi, MD.
The C-flex IOL (Rayner) has an “enhanced edge design” compared to its predecessor, the CenterFlex, Dr. Nishi said. The CenterFlex had a sharp optic edge design except at the optic-haptic junction, which could act as a “gateway” for lens epithelial cell proliferation onto the posterior capsule.
The redesigned C-flex IOL has a sharp edge all the way around the optic to prevent cell proliferation, he said.
Dr. Nishi and colleagues in Heidelberg, Germany, implanted the C-flex lens in 42 eyes as part of a study for U.S. Food and Drug Administration approval. At 2 years, mean best corrected visual acuity averaged 0.83 in these eyes, with almost no PCO development, Dr. Nishi said.
“It seems the 360° enhanced edge delayed PCO development,” he said.
Heparin-treated hydrophilic acrylic IOL works well in uveitic eyes
A heparin surface-modified hydrophilic acrylic lens has shown good biocompatibility and centration in uveitic eyes, according to Claudette Abela-Formanek, MD.
Dr. Abela-Formanek and colleagues at the Medical University of Vienna prospectively evaluated the biocompatibility of the three-piece, square-edged BioVue 3 IOL from Ophthalmic Innovations International in 30 patients with both cataract and uveitis.
At 1 year follow-up, eyes showed no significant difference in mean aqueous flare compared to preoperative levels, she said. Seven of the 30 IOLs produced “mild cellular reaction,” but it was not clinically significant, she noted.
Five patients required Nd:YAG laser capsulotomy — two with primary fibrosis and three with active cell proliferation, “comparable to hydrophobic lenses,” she said. No eyes had uveitis flare-ups after cataract surgery, she added.
“The [heparin surface-modification] is responsible for the significantly reduced cellular reaction in eyes with ongoing chronic inflammation,” Dr. Abela-Formanek said.
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Image: Stiglich JM, OSN |
Vitreous may contribute to accommodation in 1CU IOL, study suggests
An accommodative lens demonstrated less movement in vitrectomized eyes than in nonvitrectomized eyes, suggesting that the vitreous may play a role in the pseudoaccommodative action of the lens, according to Joanne Hancox, FRCOphth.
Ms. Hancox and coworkers analyzed the movement of the HumanOptics 1CU lens in 20 eyes during a postoperative period of 18 to 24 months. The purpose of the study was to investigate the effects of previous vitrectomy on the movement of the lens, as well as the effects of capsular fibrosis, postoperative time and Nd:YAG laser capsulotomy.
Seven of the 20 patients had undergone vitrectomy before cataract surgery, and their results were compared to those of patients who had not undergone vitrectomy, Ms. Hancox said.
Significantly more pilocarpine-induced forward movement (268 µm) was seen in the nonvitrectomized eyes, compared with movement of 80 µm in the vitrectomized eyes, Ms. Hancox said.
“Vitrectomized eyes had significantly less IOL movement than nonvitrectomized eyes, suggesting a contribution of the vitreous to accommodation in pseudophakic eyes,” she said.
The study also found more movement of the lens in eyes with a YAG capsulotomy than in those without, Ms. Hancox said.
There was no significant change in the amount of IOL movement over time, she said, suggesting that the 1CU has limited movement even before capsular fibrosis takes place.
Dislocation, decentration most common reasons for foldable IOL explantation
Dislocation and decentration remain the most common reasons for explantation of foldable IOLs, according to a survey. The finding highlights the need for good surgical techniques, one of the investigators said.
The survey, which was conducted jointly by the ESCRS and the American Society of Cataract and Refractive Surgery (ASCRS), analyzed reasons for foldable IOL explantation or secondary intervention. The survey was given to all ESCRS and ASCRS members through 2005.
Specifically, the survey addressed single-piece plate IOLs, one-piece IOLs with haptics, three-piece IOLs and multifocal IOLs manufactured using hydrophilic acrylic, hydrophobic acrylic or silicone polymers.
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![Nick Mamalis, MD [photo]](/~/media/images/news/print/ocular-surgery-news/2007/06_june_1/mamalis_70_90_22173.jpg "Nick Mamalis, MD [photo]")
Nick Mamalis, MD, of the Moran Eye Center in the United States, said the most common problems reported were glare or optical aberrations. Incorrect lens power followed dislocation and decentration.
However, dislocation and decentration were reported as the most common problems with three-piece silicone IOLs and single-piece plate silicone IOLs. In contrast, incorrect lens power was the main problem with three-piece acrylic lenses and single-piece lenses with haptics, he said.
For the first time, calcification and opacification were reported in the survey with three-piece hydrogel IOLs. But, “this was seen exclusively with hydrogel or hydrophilic acrylic IOLs,” he said, noting that these problems appeared in hydrophilic acrylics 2 to 3 years after they were approved for surgical use.
Dr. Mamalis noted that good surgical technique and accurate IOL measurements could help surgeons avoid such problems. New formulas and measurements for axial length are also needed, he said.
AquaLase more traumatic in grade 4 vs. lower grade cataracts
AquaLase is a good option for eyes with cataracts of lower densities, but may result in more endothelial cell loss due to longer surgical time in eyes with more dense cataractous lenses, according to Oleg Fechin, MD.
Dr. Fechin, of the IRTC Eye Microsurgery Ekaterinburg Center in Russia, studied the effects of using AquaLase on cataracts of varying densities in a series of 108 eyes. The AquaLase technique is an option included with the Infiniti phacoemulsification system (Alcon).
Patients ranged in age from 16 to 74 years and were divided into four groups according to the cataract grade. The study included 66 eyes with senile cataract and 24 eyes with complicated cataract. Most cataracts were grade 2 and grade 3 densities, Dr. Fechin said.
The researchers found a proportional increase in mean procedural time with increasing cataract density, as follows:
- Grade 1 cataracts: 0.2 minutes;
- Grade 2 cataracts: 1.1 minutes;
- Grade 3 cataracts: 2.1 minutes; and
- Grade 4 cataracts: 3.6 minutes.
Similarly, the power required for procedures increased proportionately as cataract density increased, from 18% for grade 1 cataracts to 65% for grade 4 cataracts, Dr. Fechin said.
Endothelial cell loss did not significantly differ from grades 1 to 3. However, eyes with grade 4 cataracts had a significantly greater endothelial cell loss with AquaLase, averaging 14% compared to 11% for standard phaco.
“The traumatic effects of AquaLase on the eye are comparable to phaco,” Dr. Fechin said. “AquaLase may not be justified in cases with grade 4 nucleus.”
Refractive Surgery
Phakic IOL shows good safety profile in trials, surgeon says
Data from European clinical studies investigating an angle-supported phakic IOL for correcting high myopia show a good safety profile for the lens with minimal endothelial cell loss, according to Thomas Kohnen, MD.
 Thomas Kohnen, MD, presented data from European clinical studies investigating an angle-supported phakic IOL for correcting high myopia. Image: Schultz J, OSN |
Dr. Kohnen, of the Johann Wolfgang Goethe University in Frankfurt, Germany, studied the safety outcomes for 323 patients implanted with the Alcon AcrySof phakic IOL. The study was part of phase 2 and phase 3 European clinical trials.
“We need to look at the safety issue. We need to be sure we don’t cause problems for our patients,” he said.
According to Dr. Kohnen, patients maintained best corrected visual acuity through follow-up at 6 months, 1 year and 2 years. Only one out of 112 patients lost two or more lines of BCVA at the 2-year follow-up, he said. He noted that patients rarely lost more than one line.
Patients had a surgical loss of 3.69% of central corneal cell density and a loss of 4.05% of peripheral corneal cell density, which manifested between 3 and 6 months postop.
Chronic corneal cell loss from 6 months to 1 year follow-up averaged 0.19% in the central area and 1.09% in the periphery, Dr. Kohnen said. At 18 months follow-up, chronic corneal cell loss averaged 0.91% in the central cornea and 0.94% in the periphery.
“The endothelial cell density data indicate adequate clearance between the IOL and the cornea,” Dr. Kohnen said. He noted that the outcomes support continued investigation.
White-to-white distance potential predictor of pupil size changes
Pupil size can change depending on the white-to-white distance in eyes implanted with an iris-fixated IOL, according to Sabine Buchner, MD.
Dr. Buchner and colleague H. Burkhard Dick, MD, PhD, studied 46 eyes implanted with Artisan iris-claw lenses (Ophtec) in order to evaluate intra-individual changes in pupil size.
Eyes were divided into two groups based on white-to-white measurements. Thirty-four eyes had a white-to-white measurement of less than 12.5 mm, and 12 eyes had a white-to-white measurement of 12.5 mm or more. All measurements were made using the IOLMaster (Carl Zeiss Meditec) under scotopic, mesopic low and mesopic high illumination conditions both pre- and postoperatively, with an enclavation distance of 8.5 mm, she said.
The researchers found that eyes with a white-to-white distance less than 12.5 mm had a 6.1% mean pupil size reduction, compared to a 14% mean reduction in eyes with a white-to-white distance of 12.5 mm or more.
The difference was particularly pronounced under mesopic low illumination, Dr. Buchner noted.
“A restriction of the pupil size in eyes with larger white-to-white distance under mesopic low and high illumination conditions can be expected and, therefore, may potentially reduce incidence of photic phenomena,” she said.
Limited PRK feasible in keratoconus patients following UVA corneal cross-linking
Cross-linking of corneal collagen using ultraviolet-A radiation, followed by topography-guided PRK, can effectively improve vision in patients with keratoconus and post-LASIK ectasia, according to John Kanellopoulos, MD.
“Collagen cross-linking is a rapidly growing practice in refractive surgery. It needs caution, but results are rewarding,” Dr. Kanellopoulos said. “We now have the experience of a considerable number of cases of both keratoconus and corneal ectasia that were effectively treated with this modality.”
At 16 months’ follow-up, corneal ectasia had stabilized in all cases, and corneal flattening was obtained in proportion to cone size, for an average of 3 D. Some eyes also obtained a reduction in spherical equivalent, and the procedure caused no changes in endothelial cells, Dr. Kanellopoulos said.
In 27 eyes with keratoconus, the UVA collagen cross-linking treatment was followed by limited topography-guided ablations to enhance visual rehabilitation. Several eyes with post-LASIK ectasia were similarly treated. For both conditions, patients experienced a considerable improvement in vision, he said.
“In one patient with post-LASIK ectasia and Intacs segment implants (Addition Technology), [uncorrected visual acuity] was 20/400. We removed the Intacs and performed the UVA treatment, obtaining a visual acuity of 20/80. Following topography-guided treatment, 12 months postop, the patient had achieved 20/20,” Dr. Kanellopoulos said.
This case series shows that UVA corneal cross-linking can be used as a pre-treatment to enable ecstatic corneas to undergo a limited 50-µm treatment with topography guided PRK, which would be otherwise contraindicated, he noted.
“Our therapeutic goal was not emmetropia, but improved best spectacle corrected visual acuity. Some of these patients now wear soft contact lenses or glasses,” Dr. Kanellopoulos said.
This technique may be seen as a means for preventing the need for penetrating keratoplasty, he added.
LASEK with MMC prevents haze in patients unsuitable for LASIK
Mitomycin-C can allow surgeons to perform LASEK in patients who are unsuitable for LASIK, according to Iwona Liberek, MD.
Dr. Liberek, of the Medical University of Warsaw, Poland, reviewed her 2-year results of 968 patients treated with LASEK and with 0.02% mitomycin-C (MMC) for medium to high refractive errors.
Patients had been selected for LASEK because of insufficient corneal thicknesses for LASIK, Dr. Liberek said. MMC was applied with a Spongostan film for 30 seconds to 1 minute after ablation.
At 28 months’ follow-up, late haze had appeared in just 61 patients, she said, noting no patients required re-operation.
“For the LASEK procedure, the use of mitomycin-C allows for qualifying patients with large errors for whom it would be dangerous to undergo the LASIK procedure,” Dr. Liberek said.
“Based on 2 years of observation, the use of mitomycin-C seems to be a safe method to prevent such complications as haze, which is confirmed by confocal microscope examination,” she said.
Presby-LASIK accurate, safe at 1 year in multicenter study
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![W. Bruce Jackson, MD [photo]](/~/media/images/news/print/ocular-surgery-news/2006/10_october_15/jackson_70_90_18789.jpg "W. Bruce Jackson, MD [photo]")
Presby-LASIK is a safe, effective option for restoring near vision in young presbyopic patients, according to the results of a multicenter study by Canadian investigators.
“Patients regain near vision without giving up distance focus, and most of them achieve complete spectacle independence,” said W. Bruce Jackson, MD, one of the investigators.
Dr. Jackson compiled 1-year follow-up data for 93 eyes of 56 hyperopic patients. The mean age of the patients was 55 years. Presby-LASIK can be performed using several ablation profiles, Dr. Jackson noted. In this study protocol, the central cornea was shaped for near vision and the periphery for distance vision, he said.
Most patients were treated bilaterally. Surgeons used either the Amadeus microkeratome (Advanced Medical Optics) or the IntraLase femtosecond laser to create the flap, and the Visx Star S4 WaveScan (Advanced Medical Optics) was used for ablation in all cases.
Preoperatively, mean sphere was +1.67 D and mean cylinder was +0.43 D. At 1 year, all patients achieved 20/25 or better distance visual acuity and J3 near acuity unaided. In addition, 85% achieved 20/25 at distance with J1 at near, and 80% were within +0.5 D of emmetropia, Dr. Jackson said.
Loss of contrast sensitivity was within normal limits. Because the ablation profile created a more prolate central cornea, there was a change in spherical aberration from positive to negative. Coma increased slightly but was stable over time.
Most patients were spectacle independent, and some used glasses occasionally.
“Patient satisfaction was extremely high; they were really delighted with their results,” Dr. Jackson said.
Follow-up in the study is ongoing, he said.
“Presby-LASIK is a really good alternative for young presbyopes with low refractive errors who don’t want intraocular surgery,” Dr. Jackson concluded. “In pseudophakic patients who have a residual refractive error it could be used to improve both distance and near vision.”
Results, he added, should improve further with a new ablation profile that provides better registration and centration.
PRK, LASIK stable at 10 years in large series
PRK and LASIK outcomes were predictable, safe and stable in a large series of patients with 10 years’ follow-up, according to OSN Europe/Asia-Pacific Edition Associate Editor Jorge L. Alió, MD, PhD.
Dr. Alió reported the 10-year results of PRK and LASIK in 800 eyes treated for myopia or myopic astigmatism. All procedures were performed with the Visx Twenty/Twenty excimer laser.
In 500 eyes, PRK was used to treat a mean spherical equivalent of –6.5 D, and in 300 eyes LASIK was used to treat a mean spherical equivalent of –11.8 D. For the data analysis, the investigators divided the eyes according to severity of myopia. The low myopia group included 228 eyes treated with PRK and 21 eyes treated with LASIK, the intermediate myopia group included 195 PRK- and 80 LASIK-treated eyes, and the high myopia group included 71 PRK- and 196 LASIK-treated eyes.
Both procedures demonstrated high predictability in low myopia, Dr. Alió said, although PRK showed a trend toward better predictability than LASIK. LASIK showed better predictability and safety in intermediate and high myopia, he said.
The Twenty/Twenty laser was manufactured by Visx prior to that company’s acquisition by Advanced Medical Optics.
At 5 years, LASIK patients remain happy with results
Patients remain happy with their LASIK results 5 years after undergoing the surgery, according to Arthur Cummings, MD. Additionally, most patients would have the procedure again or would recommend it to a friend, he noted.
Dr. Cummings and colleagues invited all 1,250 patients who underwent LASIK at their facility in 1999 and 2000 back for a free 5-year follow-up exam. Ninety-seven patients came for the exam and filled out a questionnaire to assess how their current vision compared to vision before LASIK. It also asked about nighttime vision problems, whether they would have LASIK again and whether they would recommend it to a friend or relative.
Of those who responded to the questionnaire, 6.2% indicated they had worse vision now than before LASIK, and 21% said their night vision was worse than it was before. “But when you ask people if they would do laser again, everyone, bar none, said they would do it again, and 100% said they would refer a friend,” Dr. Cummings said.
The refractive outcomes in the clinical exams were “excellent,” Dr. Cummings said, noting that patients were happy with their outcomes. Uncorrected visual acuity averaged better than 20/20 and spherical equivalent averaged –1.3 D, he said.
Dr. Cummings noted that among patients with prolate corneas, there was only one complaint of poor night vision. Complaints of night vision were more common among patients with spherical or oblate corneas, he said.
“The postop corneal profile played an important role in overall visual satisfaction with both day and night vision,” he said. Treatment decentration seemed to have little effect on visual satisfaction, as did whether or not the patient was treated with monovision correction, he said.
LASIK-lens combination allows multifocal IOL use in astigmatic patients
Refractive lens exchange combined with LASIK can extend the indications for using a multifocal IOL to include patients with astigmatism, according to Pierre Levy, MD.
Dr. Levy, of Clinique Saint Roch in France, explained his approach to managing existing astigmatism and presbyopia using astigmatic LASIK after implantation of the Alcon AcrySof ReSTOR multifocal lens. The data were extracted from his clinical experience with 150 eyes, he said.
“The use of LASIK to correct preoperative astigmatism is a good means to extend the indications to patients whose astigmatism, until now, was a contraindication for a ReSTOR lens implantation,” Dr. Levy said. “Our study shows a bioptic approach is a good option in patients with corneal astigmatism between 1.5 D and 4 D.”
Dr. Levy reviewed his results in 24 eyes of 12 patients with corneal astigmatism between 1.5 D and 4 D in whom he implanted the ReSTOR lens. All patients were older than 54 years, and preoperative ametropia ranged from –2 D to +3 D.
Surgery was performed in two stages, beginning with clear lens exchange followed by LASIK after 3 months, Dr. Levy said. Eyes with astigmatism greater than 1.25 D should be targeted for slight myopia when the refractive lens exchange is performed, he said.
At the 3-month follow-up, spherical refraction ranged from –0.5 D to +0.75 D, and all patients were within 1 D of emmetropia by 6 months’ follow-up. Residual cylinder ranged from –0.25 D to 0.5 D, uncorrected visual acuity for distance ranged from 20/25 to 20/20 and uncorrected near visual acuity ranged from J3 to J1.
Artiflex an option for mild keratoconus, residual myopia after LASIK, PRK
In some challenging eyes, Ophtec’s Artiflex phakic IOL can produce visual results that are comparable with its results in uncomplicated high myopia, according to Antonio Marinho, MD.
Dr. Marinho and colleagues compared clinical results with the Artiflex foldable anterior chamber phakic IOL in three conditions: uncomplicated myopia, mild keratoconus and residual myopia after corneal refractive surgery.
The myopia-only group included 91 eyes of 52 patients with a mean refractive error of –8.73 D. The mean age of the patients was 30 years, and they were followed for up to 36 months postop, Dr. Marinho said.
The keratoconus group included 11 eyes of seven patients with a mean refractive error of –7 D. The mean age of patients in this group was 29 years. For 10 of these eyes, patients had initially sought corneal refractive surgery, but examiners detected mild keratoconus, making them ineligible for such surgery. One eye had previously been implanted with Intacs ring segments (Addition Technology) for keratoconus, and the Artiflex lens was used to correct residual myopia.
A third group of 13 eyes of nine patients had previously undergone corneal refractive surgery; PRK in 11 eyes and LASIK in two eyes. For these patients, whose mean age was 38 years, residual myopia averaged 5.32 D, but none showed signs of corneal ectasia, Dr. Marinho said.
“Accuracy was comparable in the myopic group and in the keratoconus group, where about 90% of the eyes were plano. It was slightly lower in post-refractive [surgery] group because a number of these patients had a residual astigmatism that could not be treated by further laser surgery,” he said.
Phakic IOL calculation was similar for both the keratoconus group and the myopia-only group, Dr. Marinho noted. “But in the post-refractive [surgery] group, we had to aim for a slight myopia, between –0.75 D and –1 D, because if we aimed for emmetropia the result would have been hyperopic,” he said.
“Efficacy was comparable in the three groups,” he said. Most eyes maintained preoperative best corrected visual acuity, no eyes lost BCVA and some eyes, mainly in the keratoconus group, gained BCVA.
Sub-Bowman’s flap may be preferable in LASIK, laser expert says
Thin LASIK flaps may preserve corneal stability without the induction of postoperative corneal haze or pain after refractive surgery, suggested John Marshall, PhD.
Prof. Marshall, a laser expert from St. Thomas’ Hospital in London, said that corneal surface wounds, such as those created during PRK, disrupt Bowman’s layer and weaken the cornea, in addition to causing postoperative pain for the patient. Deep-cut microkeratome flaps, if they leave a stromal bed that is too shallow, can also weaken the cornea in LASIK. But LASIK flaps cause little of the wound healing response and cellular reaction seen with surface ablation, he noted.
A thin flap, just posterior to Bowman’s membrane, created with the IntraLase FS femtosecond laser, may be the best way to avoid the problems with other approaches to corneal refractive surgery, Prof. Marshall suggested.
“I am intrigued by the ability of IntraLase to cut shallow flaps,” he said. “With a 90-µm flap, Bowman’s is intact and the epithelium is beautiful. When we lift the membrane, we don’t disturb cells, we don’t induce a wound healing reaction, and thus we preserve the biomechanics of the cornea.”
Prof. Marshall advised surgeons to think about using sub-Bowman’s membrane flaps in future refractive procedures.
First live femtosecond laser keratoplasty performed
In the live surgery session, Sheraz Daya, MD, became the first surgeon to perform therapeutic keratoplasty with femtosecond laser at an ophthalmic conference.
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![Lucio Buratto, MD [photo]](/images/osnea/200610/buratto.jpg "Lucio Buratto, MD [photo]")
“This is the most important improvement in corneal surgery in the past 30 years,” said session chairperson, Lucio Buratto, MD.
The session, jointly chaired by Dr. Buratto and Tayo Akingbehin, MD, also included implantations of the VeriFlex phakic IOL (Advanced Medical Optics), the Icare Evolution phakic IOL (Corneal) and the Artiflex phakic IOL (Ophtec), and reflected many of the issues discussed during the conference.
Dan Z. Reinstein, MD, also performed a wavefront topography-based repair of a complex post-refractive case on a fellow ophthalmologist.
The case of therapeutic keratoplasty closed out the session and featured an introduction by Stephen G. Slade, MD, donor tissue preparation by Thomas Neuhann, MD, as well as the keratoplasty by Dr. Daya. All surgeries were performed at Moorfields Eye Hospital.
Concerns remain over contact between PRL and natural lens
The Phakic Refractive Lens (PRL) from IOLTech seems to be a promising choice for refractive surgery in high myopic and hyperopic patients unfit for corneal surgery, but more long term results are needed to assess the complications, particularly, in cataract surgery, according to several surgeons speaking at the ESCRS meeting here.
In a study carried out at the Dunya Eye Hospital in Istanbul, Turkey, 115 eyes were included. Of these, 32 were hyperopic and 83 myopic.
“Visual results were satisfactory,” said Serife Atun, MD. “Refraction improved from –12 D to –1 D in the myopic group and from +9.50 D to plano in the hyperopic group”.
One lens was damaged during surgery and raised IOP occurred in one eye from topical steroids. Decentration and glare were found in two eyes. Anterior capsule opacification occurred in one eye there was one case of endophthalmitis.
“We are concerned about potential complications like cataract, endophthalmitis, IOL decentration and the IOL dropping into the vitreous, which has occurred in other case series. Longer-term results are needed to assess the rate of these complications,” Dr. Atun said.
In a German study of 44 myopic patients with a minimum follow up of 2.5 years, visual results were also very good.
“Our patients’ refraction ranged between – 4 D and –20 D, with a high proportion of high myopes. After implantation, none of them were worse than –1 D,” said Anja Liekfeld, MD.
Also in this case series, besides early complications, surgeons found one case of membrane formation behind the PRL. Cataract due to surgical trauma occurred in one case and subcapsular cataract 3 years postop occurred in another patient. One PRL had to be explanted because of recurring decentration.
“The PRL is the competing model of the ICL lens. It is supposed to float, and therefore avoid contact with the crystalline lens. However, to compare it with the ICL, particularly in relation to cataract formation, we need more long-term results,” Dr. Liekfeld said.
A Swedish study with the Visante OCT from Carl Zeiss Meditec, evaluating the distance between the PRL and crystalline lens in myopic and hyperopic eyes with and without accommodation, found that in most, but not all cases, there is no contact between the PRL and crystalline lens.
“In some cases, during accommodation, the space was even increased. However, in other eyes a significant decrease was seen, and in some cases the PRL came into contact with the crystalline lens,” said Annemari Koivula, MD, of St. Erik’s Eye Hospital in Stockholm.
The PRL 100 had the best performance in this respect, probably due to better sizing. No correlation between age and distance was found.
Toric ICL results ‘better than LASIK’
Toric ICL implantation appears to be a safe, effective and predictable method for the correction of high myopic astigmatism in the long term, according to several studies.
“This phakic implant gives even better results than LASIK. It is highly accurate, and complications are very few and manageable. Patient satisfaction is very high. However, sizing and measurement of sulcus dimension can still be a problem,” said Baha Toygar, MD, of the Dunya Eye Hospital, Istambul, Turkey.
Dr. Toygar has been using the ICL for 3 years, and has implanted it in 361 eyes, 178 of which (49%) received a toric lens (TICL). The results in 27 eyes of 17 patients were analyzed. Preoperative spherical equivalent was –10.7 D, preoperative atigmatism was –2.6 D (range 1 D to –5.5 D). Minimum follow up was 12 months.
“After implantation, UCVA increased from counting fingers to 20/32 and BCVA from 20/40 to 20/25. More than 70% of the eyes gained at least twoSnellen lines of BCVA, and no eye lost Snellen lines. Spherical equivalent improved to –0.42 and mean cylinder to –0.50,” he said.
As far as complications were concerned, one eye had TICL exchange due to excessive vaulting, and two eyes had repositioning from misalignment.
“In one of these eyes the lens rotated again and we exchanged it, but the result was an anterior subcapsular cataract. We performed phacoemulsification with IOL implantation and IntraLASIK, and the patient is now 20/20,” Dr. Toygar said.
In another case series, 32 eyes of 20 patients were implanted with the TICL. Twenty seven eyes achieved 12 months of follow up. Preoperative spherical equivalent was between –5 D and –15 D and spectacle-corrected VA was 20/20 or better.
“After implantation the spherical equivalent was between –1 D and –0.5 D, and uncorrected visual acuity was 20/20 or better in 89% of the eyes. Two or more lines of best corrected vision were gained by 22% of the eyes,” said Alaa El-Danasoury, MD, of Maghrabi Eye Hospital in Jeddha, Saudi Arabia.
Complications consisted of wrong axis alignment in one eye, transient high vault in two eyes and transient ocular hypertension in one eye.
“The TICL is effective, highly predictable and relatively safe in the correction of compound myopic astigmatism. A widely dilated pupil is mandatory for proper axis alignment, which can still be a problem in some cases,” he said.
Long-term results confirm safety, efficacy of Artisan lens
Long-term studies with the Artisan lens (Ophtec) at the University of Maastricht, The Netherlands, confirmed the safety and efficacy of this phakic implant in a series of different cases.
“Ten-year follow-up in 89 eyes of 49 patients showed the refractive stability, safety and efficacy of the myopic Artisan,” said Grace Tahzib, MD. “The mean spherical equivalent was –0.70, with no significant change between 1, 6 and 10 years. Most of the eyes retained their BCVA or gained one or more lines. Only a small minority lost a few lines. At 10 years, 93% reached a BCVA of 20/40 or better and 80% reached a UCVA of 20/40 or better.”
Mean IOP was 15.4 mm Hg and no significant endothelial cell loss was found.
“A relative gain of 8.5% endothelial cells was found in our group of patients, which was probably due to discontinuation of contact lens wear,” she said.
In 36 eyes of 35 patients a toric Artisan was implanted after penetrating keratoplasty. The mean follow up was 29 months, ranging between 1 and 4 years.
“Treatment was aimed at reducing astigmatism and ametropia to enable spectacle correction,” said Niels De Vries, MD.
“After implantation, the mean sphere was almost reduced to 0 D with low standard deviation. The mean cylinder fell from –7 D to –2 D at the final follow up. BCVA following implantation was 20/40 in more than 80% of the eyes. It remained relatively stable in the majority of patients. There was a gain of at least two lines in 8% as well as a loss of visual acuity of more than two lines in 8%. In two of these three patients this was due to rejection of the graft, in the third rejection was from slow endothelial decompensation,” Dr. De Vries said.
PresbyLens safe, effective in presbyopia correction
Ongoing experience with the PresbyLens intracorneal implant (ReVision Optics) suggests that this method of correcting presbyopia is safe and effective.
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![Stephen G. Slade, MD [photo]](/~/media/images/news/print/ocular-surgery-news/2007/05_may_1/slade_70_90_21768.jpg "Stephen G. Slade, MD [photo]")
“It is a minimally invasive, additive treatment, which makes more sense in presbyopia than any subtractive treatment. The lens is adjustable, exchangeable, removable and it is made of a highly biocompatible material,” said Stephen G. Slade, MD, who spoke on behalf of Jon Dishler, MD.
The lens is designed to be placed under the cornea. It provides a center near add zone and a paracentral intermediate zone, allowing the remaining cornea to be used for distance vision. Placed in the non-dominant eye, it is used in conjunction with myopic LASIK targeted for plano in both eyes, according to Dr. Slade.
In Dr. Dishler’s study, 15 patients were implanted with the PresbyLens. The LASIK procedure and lens implantation was performed using a Nidek laser and keratome.
“All patients achieved an uncorrected distance vision of 20/32 or better and an uncorrected near vision of 20/40 or better. All of them are spectacle free for distance and near vision, and the majority for intermediate vision. None of the patients lost more than 2 lines of BCVA,” he said.
In his own series of 18 patients Dr. Slade obtained comparable results. He performed the LASIK cut with the IntraLase or the Hansatome microkeratome (Bausch & Lomb).
“Centration is the most critical issue with this lens,” he pointed out.
“This technology is similar to monovision, a balance between how much you lose at distance compared to how much you gain at near. But while the true monovision is about one-to-one, with this technique you gain more lines at near than what you lose at distance,” he concluded.
Cornea/External Disease
Risk factors for post-LASIK ectasia are still unclear
Although occurring in a small minority of cases, post-LASIK ectasia is still a concern, and risk factors are not entirely clear, according to several surgeons.
A first retrospective analysis of the most commonly recognized risk factors (preoperative corneal thickness of less than 500 µm, residual stromal thickness of less than 250 µm, age of less than 25 years, high myopia with corneal steepness of more than 47 D, against-the-rule astigmatism of 1 D or more) in a large number of patients led Perry S. Binder, MD, to observe that eyes can have one or more risk factors and not develop ectasia, or can have no risk factors and yet develop ectasia.
“In my group of patients, I had 400 eyes with less than 500 µm of central corneal thickness preoperatively, 224 eyes with residual stromal thickness of less than 250 µm, 137 myopic eyes with a cornea steeper than 47.5 D, 159 eyes with against-the-rule astigmatism of more than 1 D and 473 eyes of patients younger than 25 years of age. None of these eyes developed ectasia, whereas three eyes outside of these risk factors did,” he said. He concluded that other risk factors, probably connected with the alteration of corneal biomechanics produced by the LASIK, must be responsible for ectasia.
Flap thickness with mechanical microkeratomes is quite unpredictable, “and even if we measure a safe central thickness, because of the meniscus shape of that flap, the peripheral part of that flap is going to be a lot deeper … , and this affects the biomechanical stability of the cornea,” Dr. Binder said.
Conversely, according to Luis Oliveira, MD, “in determining corneal stability after LASIK, the flap is not important, and the stromal bed is the decisive factor.”
He retrospectively reviewed 2,500 LASIK eyes, of which six developed keratectasia.
“None of these cases had preoperative keratoconus. In all of them preoperative myopia was higher than 8 D and the residual stromal bed was less than 250 µm,” he said.
A third retrospective study was presented by Sergey Nikulin, MD, who analysed a large group of 23,990 eyes of 12,077 patients who underwent LASIK. Post-LASIK ectasia developed in 13 eyes of 11 patients.
“In these eyes, the most prominently recurring factor was a positive coma of more than 0.7 µm. In our opinion, the high level of positive coma z(3;1) is the most important index for predictability of keratectasia,” Dr. Nikulin said.
Femtosecond laser-assisted keratoplasty shows promise
Lamellar keratoplasty performed using a femtosecond laser restored physiological corneal thickness and shape in a small patient cohort, according to a study conducted by Luigi Mosca, MD, of the Catholic University of Sacro Cuore Eye Clinic in Italy.
The IntraLase FS femtosecond laser was used to perform lamellar keratoplasty in 18 eyes of 18 patients whose mean age was 37 years. The study included 11 eyes with keratoconus, three eyes with corneal scarring due to infection and four eyes with post-traumatic anterior stromal opacities.
Donor lamella thickness averaged 382 µm, and residual stromal bed thickness averaged 154 µm.
Preoperatively, patients had a mean uncorrected visual acuity of 0.13 and best corrected visual acuity of 0.33, Dr. Mosca said.
The researchers found slight improvements in UCVA and BCVA at up to 3 months postop. Vision improved further after suture removal at around 4 months. At 12 months’ follow-up, mean UCVA improved to 0.45 and a mean BCVA improved to 0.65, he said.
Cystic fibrosis patients need careful dry eye evaluations
Patients with cystic fibrosis have hyposecretion of tear fluid and low tear film stability, according to the results of a study presented here.
These patients should routinely undergo dry eye testing to evaluate and diagnose their ocular changes, the authors said.
Malgorzata Mrugacz, MD, and colleagues studied 24 patients with cystic fibrosis (mean age, 14.32 ± 3.01) and 24 patients without the genetic condition (mean age, 13.92 ± 3.32) at the Medical University of Bialystok, Poland.
All the cystic fibrosis patients were taking vitamin A supplements. All patients underwent opthalmic exams, including dry eye testing, slit lamp biomicroscopy and ophthalmoscopy, according to the authors.
Five patients with cystic fibrosis reported itching, burning or tearing, while two patients from the control group reported these symptoms, according to the study. There was no statistically significant difference in terms of clinical blepharitis between the two groups.
The authors reported that Schirmer test scores were significantly lower in patients with cystic fibrosis (9.68 ± 5.54 mm) compared to the control group scores (25.21 ± 3.08 mm). Tear film breakup time was also significantly lower in the cystic fibrosis group (5.3 ± 2.6 seconds) compared to the control group (9.9 ± 1.1 seconds).
There was no statistically significant difference between the two groups’ lissamine green scores, the authors noted.
Glaucoma
SLT still effective in 50% of eyes at 5 years
Selective laser trabeculoplasty has a survival rate of 50% at 5 years after treatment. After a single 180· treatment, the average “life” of a selective laser trabeculoplasty (SLT) procedure was 31 months, according to a study by Rahul Yadav, MBBS, MSOphth.
“SLT successfully reduces IOP as a primary or secondary treatment,” Dr. Yadav said. “IOP reduction is very strongly related to baseline IOP, and the probability that an eye will successfully complete 5 years after one treatment of SLT is 0.5.”
Dr. Yadav reported the results of a retrospective study of all 546 eyes treated with SLT at Clayton Hospital in Wakefield, England, from 2000 to 2006. He said IOP before SLT averaged 26.6 mm Hg. IOP decreased an average of 24% at 1 week, 29% at 6 months, 28% at 1 year and 33.8% at 5 years follow-up.
As a primary treatment in 279 eyes with “virgin trabecular meshworks,” there was a 33% mean IOP reduction from baseline at a mean follow-up of 32 months, he said. As a secondary treatment in 167 eyes of patients with glaucoma uncontrolled using one medication, there was a 29% mean IOP decrease at a mean follow-up of 24.6 months.
The reductions in both groups were “statistically and clinically significant,” Dr. Yadav said. The difference in IOP reductions between the two groups was not statistically significant, he noted.
The researchers also found a 50% probability of survival at 5 years for SLT-treated eyes. “Although there was a steep attrition rate in the early period … after 3 years, the rate drops to less than 5% per year,” Dr. Yadav said.
The survival rate in this study appears similar to rates reported for argon laser trabeculoplasty, but SLT is a less invasive treatment, he noted.
Canaloplasty procedure shows promise for OAG in European study
A new canaloplasty procedure is showing better pressure-lowering efficacy over viscocanalostomy for open-angle glaucoma, according to Manfred Tetz, MD.
In canaloplasty, a microcatheter manufactured by iScience is passed into and around Schlemm’s canal. Viscoelastic is then injected through the microcatheter to dilate the canal. A suture is attached to the catheter and retracted through the canal, and the two ends are tied together, leaving slight tension on the canal.
Dr. Tetz examined the 6-month results of a multicenter European study involving 65 patients. In the study, patients had a preoperative IOP of 21.9 mm Hg and used an average of two medications. At 6 months’ follow-up, mean IOP decreased 37% to 13.8 mm Hg, he said.
Dr. Tetz also reviewed his own results from his first 20 patients, nine of whom underwent canaloplasty in combination with cataract surgery. At 6 months’ postop, patients had a mean IOP of 13.7 mm Hg, he said.
“Comparing this to our previous viscocanalostomy data, we were about 3 mm Hg on average lower” with canaloplasty, Dr. Tetz said.
Dr. Tetz noted the procedure involves a learning curve. In combined U.S. and European data for 188 patients with no previous surgery, 89.4% were successfully catheterized. But if the first 10 cases by each surgeon are excluded, 100% of eyes were successfully treated, he said.
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