- Novel treatment can restore good vision in patients with stage 4 DLK
- Achieving success with new generation of multi-focal IOLs depends upon patient selection and patient education
- Herbal remedy may contribute to intraoperative floppy iris syndrome (IFIS)
- Identifying risk factors for keratoconus and corneal ectasia after LASIK
- Comparison of two types of accommodative IOLs finds slight advantage for the 1-CU lens
- Patients with cornea guttata and family history of Fuchs’ endothelial dystrophy appear prone to poor LASIK outcomes
- Some patients may develop subcapsular cataract and vision loss following ICL implantation
- High myopia and deep ablation depth linked to increased risk of post-LASIK dry eye
- MMC application during photorefractive keratectomy appears safe and effective
- Journal of Refractive Surgery now publishes nine times a year
- Housing and tour information for the 2006 ISRS/AAO meeting now live
- ISRS/AAO now accepting applications to join in 2006
- Upcoming Meetings
- ESCRS publishes results of endophthalmitis prophylaxis study
- Light adjustable lens shows promise for improved vision for cataract patients
- IntraLase Corp. launches faster femtosecond laser
- FDA approves Bausch & Lomb’s new, faster laser
- British health organization issues guidance on laser eye surgery
Novel Treatment Can Restore Good Vision in Patients With Stage 4 DLK
Brian R. Will, MD, presented a paper at the American Society of Cataract and Refractive Surgery meeting earlier this month that contradicts widely-held theories about the pathophysiology of this feared complication of LASIK. Dr. Will said that the condition is caused by highly localized tissue edema, not tissue necrosis. Under his novel treatment protocol, all six patients (eight eyes) in his case series recovered to 20/15 or 20/20 vision within a few months. Their corneas appeared indistinguishable from routine LASIK cases with no scarring or microstriae. No eye demonstrated stromal loss. Only four of eight eyes underwent conventional excimer laser enhancement procedures. No patient complained of glare, halos or other visual disturbances.
Achieving success with new generation of multi-focal IOLs depends upon patient selection and patient education
Speakers at this week’s meeting of the American Society of Cataract and Refractive Surgery repeatedly stressed that with careful attention to patient selection and patient education many patients can achieve spectacle independence with the new multi-focal IOLs, but it’s not for everyone. Night pilots, night drivers and those who spend a lot of time in front of a computer are probably not good candidates. Patients must be warned of increased incidence of nighttime halos and glare and decreased contrast sensitivity. Avoid patients who have unrealistic expectations. Make sure patients understand that they can’t expect to see like they did at age 18. Let them know they can increase their independence from glasses but that some 20 percent of patients continue to wear glasses. Prepare patients for the likely need for a LASIK or PRK touch up to fine tune the prescription. The physician also needs to increase chair time with patients to properly match them up with the right lens. If a patient’s life revolves around intermediate vision, a refractive IOL such as the ReZoom lens might be more appropriate. Diffractive IOLs such as the ReSTOR lens and the Tecnis Multifocal offer excellent near and distance vision and patients experience fewer problems with night vision, but there’s a gap in intermediate vision as well as a loss in contrast sensitivity. As promising as these new lenses are, R. Bruce Wallace III, MD, reminded physicians that there are not a lot of good clinical studies comparing the different among lenses and assessing how well they perform. For example, we know patients can achieve good intermediate vision, but how functional is their vision after 30 minutes on a computer. Other considerations: posterior capsular opacification (even mild PCO seems to affect vision more than one would expect) and dry eye (which he treats aggressively before surgery with restasis and punctal plugs). Many patients who have issues with glare also had dry eye pre-op. Despite the drawbacks, multi-focal IOLs represent the future said Stephen S. Lane, MD, who delivered the Binkhorst Lecture. In short, physicians should under-sell these lenses and over-deliver. But most importantly, he said, physicians should “stop waiting on the sidelines, stop thinking about it and just do it.”
Herbal remedy may contribute to intraoperative floppy iris syndrome (IFIS)
A paper delivered at this week’s meeting of the American Society of Cataract and Refractive Surgery concludes that patients taking saw palmetto before cataract surgery may experience IFIS. David F. Chang, MD, and John R. Campbell, MD, initially identified a link between the drug tamsulosin (Flomax, Boehringer Ingelheim Pharmaceuticals), the most commonly used medication to treat benign prostatic hypertrophy and IFIS. Dr. Chang says proper management of cataract cases involving IFIS should keep surgeons from experiencing complications associated with the problem. His strategy for managing this surgical problem: avoid pupil stretching. This causes the iris to act abnormally. Reduce the phaco machine settings to low-flow settings: bottle height to around 70 cm; aspiration flow rate to around 25 mL/min or less; vacuum to 250 mm Hg or less. Use iris hooks in a diamond configuration. Use various available mechanical devices. Use an ophthalmic viscosurgical device (OVD).
Identifying risk factors for keratoconus and corneal ectasia after LASIK
A committee of leading refractive surgeons brought together by ISRS/AAO and the American Society of Cataract and Refractive Surgery to summarize current knowledge of ectatic corneal disorders and ectasia after LASIK discussed their findings at the meeting of the American Society of Cataract and Refractive Surgery earlier this month. While only about 14 cases of ectasia have been reported in the literature, that number may increase, said R. Doyle Stulting, MD, PhD. Knowledge about the risks factors for corneal ectasia is increasing and some of the risk factors may be very subtle. Among the known risk factors: high myopia (higher than the typical refractive surgery candidate), a residual stromal bed less than 250 microns thick and abnormal topography (10 eyes of seven patients in his fist case series in 2003 had forme fruste keratoconus). Still, none of these risk factors are absolute predictors of its occurrence. It can develop in the absence of surgery or any risk factors. While there are no formal guidelines to date, Dr. Stulting said the committee recommends surgeons review topography prior to surgery to reduce some of the risks for ectasia after LASIK. They conclude that forme fruste keratoconus, a topographic diagnosis, implies subclinical disease with the potential for progression to keratoconus. They recommend against performing LASIK on these patients using current technology. Instead, patients with these topographic patterns – asymmetrical inferior corneal steepening or asymmetric bowtie topographic patterns with skewed steep radial axes above and below the horizontal meridian – could be offered photorefractive keratectomy with informed consent, indicating that there may still be a risk of progression to keratoconus. They also recommend that intraoperative pachymetry to determine flap thickness be considered for cases in which the calculated residual stromal bed might be near the safe lower limits for the procedure and/or the reproducibility of the microkeratome might result in a residual stromal bed less than those limits. The committee began its work after a New York jury awarded $7.25 million – the largest award yet – to a LASIK patient who claims he suffered severe vision loss from the surgery. The committee expects to produce a more evidence-based approach to the understanding of this condition. Its initial findings have also been published in the Journal of Refractive Surgery, November/December 2005.
Comparison of two types of accommodative IOLs finds slight advantage for the 1-CU lens
This comparative study included 75 patients (108 eyes) who underwent cataract surgery by phacoemulsification and IOL implantation either bilaterally or monocularly with one of two types of accommodative IOLs: the crystalens Model AT-45 (69 eyes) or the 1-CU lens from HumanOptics (39 eyes). At one year postop, 84.6 percent of the bilaterally implanted 1-CU patients and 73.6 percent of the bilaterally implanted AT-45 IOL patients achieved uncorrected distance visual acuity of 20/30 or better. A total of 42 percent of patients with the bilateral 1-CU implant and 36.8 percent of the patients with the bilateral AT-45 implant achieved uncorrected near visual acuity of J1 or better. A total of 92.3 percent of the 1-CU patients and 84.2 percent of the bilateral AT-45 patients had J3 or better near acuity. A total of 54 percent of the 1-CU patients underwent a mild myopic shift (<1.0 D); 21 percent, a mild hyperopic shift and 45 percent were emmetropic at one year postop. European Journal of Ophthalmology, January/February 2006
Patients with cornea guttata and family history of Fuchs’ endothelial dystrophy appear prone to poor LASIK outcomes
This retrospective chart review included four patients (seven eyes) with trace to 1C endothelial guttata and a family history of Fuchs dystrophy who had uneventful LASIK for the correction of myopia and myopic astigmatism. Transient corneal edema was noted in three eyes (two patients) soon after surgery. The endothelial cell count between baseline and one year was significant (P <.001), but the difference between cell count at three months and one year was not (P = .91). This may suggest most cell loss occurs in the immediate postoperative period, followed by a return to the baseline rate, and may support a causal relationship. All patients lost two lines of BSCVA. In addition, most patients experienced a significant myopic shift in the SE. The authors conclude that refractive surgeons should consider avoiding LASIK in patients with evidence of corneal endothelial abnormalities and a known family history of Fuchs’ endothelial dystrophy until further studies define more appropriate and specific guidelines. Journal of Cataract & Refractive Surgery, December 2005
Some patients may develop subcapsular cataract and vision loss following ICL implantation
This prospective study identified nine of 127 eyes (7.1 percent) that developed cataract and decreased visual acuity (four of 28 hyperopic eyes and five of 99 myopic patients). The implantable contact lens (ICL) was removed, phacoemulsification was performed and an IOL was implanted. The authors conclude that although the posterior chamber inlay as well as the cataract can be removed and better acuity can be restored, a possible complication due to the ICL implantation cannot be avoided and the accommodation in young patients lost. Journal of Cataract & Refractive Surgery, December 2005
High myopia and deep ablation depth linked to increased risk of post-LASIK dry eye
This prospective study randomized 35 patients (age 24 to 54) to have LASIK with either a superior-hinge Hansatome microkeratome (17 patients) or a nasal-hinge Amadeus microkeratome (18 patients). Post-LASIK dry eye was common, even among patients with no history of dry eye and was associated with the level of preoperative myopia (RR 0.88/each diopter, P = .04), laser-calculated ablation depth (RR 1.01/µm, P = 0.01) and combined ablation depth and flap thickness (RR 1.01/µm, P = 0.01). Researchers also observed changes in the incidence of dry eye over the six-month postop period: the greatest incidence occurred at one week (50 percent) in both groups, gradually decreasing to an overall rate of 36.36 percent in both groups and to 41.18 percent in the superior-hinge group at six months. The authors conclude that all patients should be informed the risk of developing dry eye after surgery, particularly those with high myopia. Consideration should be given to surface ablation in patients with high myopia because it carries a much lower risk for inducing dry eye. American Journal of Ophthalmology, March 2006
MMC application during photorefractive keratectomy appears safe and effective
This non-comparative, retrospective study included 536 patients (1,011 eyes) with a mean preoperative SE of -7.82 D ± 2.64 SD. After laser ablation was performed with the Nidek EC-5000 laser, a ring-shaped Merocel sponge soaked with 0.02 percent MMC solution was applied to the ablated corneal surface for 30 seconds to 2 minutes, depending on the ablation depth (30 seconds for an ablation depth from 80 to 100 mm, one minute for depths from 100 to 120 mm, and two minutes for depths greater than 120 mm). After a mean follow-up of 13 months, researchers observed few complications: haze occurred in 3.17 percent of eyes, but in most cases it was limited to grade 1. Postoperative endothelial cell density measured by specular microscopy did not show a significant difference from preoperative measurements. Delayed epithelial healing was observed in two eyes. Visual outcomes appeared excellent: 86 percent 20/20 or better visual acuity; 98 percent, 20/40 or better. Journal of Cataract & Refractive Surgery, December 2005
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Journal of Refractive Surgerynow publishes nine times a year
The benefit of membership in ISRS/AAO has just increased by three. Three additional issues of the peer-reviewed, official journal of the ISRS/AAO will be published each year. The journal also recently expanded its editorial content to include articles dedicated to lens-based refractive surgery, in addition to original research, review and evaluation of refractive and corneal surgical procedures.
Housing and tour information for the 2006 ISRS/AAO meeting now live
To reserve your hotel room, complete the online housing form and return it to United Expo at +90-232-4650086. United Expo is also organizing half day, full day and pre/post meeting tours. To reserve your spot on a tour, complete the online order form and it fax to United Expo at +90 232 465 00 86. Find all the latest information on this year’s meeting in Istanbul, including recent updates to the program and faculty listing, from our Web site.
ISRS/AAO now accepting applications to join in 2006
Membership in ISRS/AAO provides many opportunities to keep up with the latest in clinical and research developments in refractive surgery, as well as access to the world’s leading refractive surgeons for specific clinical case questions and issues. You can either apply online or download an application and send it in.
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|Upcoming Meetings || || |
May 17-20, 2006
4th SOI International Congress
| || |
June 23-24, 2006
South African Society of Cataract and Refractive Surgery Regional Meeting
Cape Town, South Africa
|May 25-28, 2006 |
19th Congress of German Ophthalmic Surgeons (DOC)
| ||June 28 - July 1, 2006|
XII International Meeting of the Mexican Center of Cornea and Refractive Surgery
May 26-28, 2006
ISRS/AAO Meeting: International Refractive Surgery: Art and Science
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July 8-9, 2006
Indian Intraocular Implant and Refractive Society Convention
|June 16-17, 2006 |
South African Society of Cataract and Refractive Surgery Regional Meeting
Johannesburg, South Africa
|Nov. 10-11, 2006|
ISRS/AAO Subspecialty Day Meeting
Sands Expo at the Venetian Hotel
Las Vegas, Nevada, USA
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ESCRS publishes results of endophthalmitis prophylaxis study
The European Society of Cataract and Refractive Surgeons recently terminated recruitment for its two-year study of antibiotic prophylaxis of endophthalmitis following cataract surgery and issued a release on the results.
Light adjustable lens shows promise for improved vision for cataract patients
The light adjustable lens is implanted using the same standard surgical techniques used in conventional cataract surgery. After the eye has healed, the surgeon adjusts the lens power to the patient's specific visual needs by directing a low intensity beam of light onto the lens from outside the eye. Early results from a clinical trial in Europe show that following light adjustment, 87 percent of patients (21 out of 24) were within 0.25 diopters (the measurement of the power of a lens) of the intended refractive result. After two years, no patients have lost any visual acuity. For the study, lenses were adjusted over a range of -1.75 to +2.25 diopters of the intended refractive result. Clinical trials in the United States are expected to begin by the end of the year.
IntraLase Corp. launches faster femtosecond laser
The company says its new 4th Generation IntraLase FS Laser, used to make the corneal flap during LASIK surgery, is twice as fast as its predecessor. Doubling the speed has reduced the time required to make the corneal flap to less than approximately 15 seconds while maintaining the procedure's excellent safety profile and visual outcomes. The company says the new laser also enables the surgeon to create a tighter spot pattern, which facilitates the lifting of the flap and reduces the potential and/or severity of post-operative inflammation.
FDA approves Bausch & Lomb’s new, faster laser
The company this week announced that the U.S. Food and Drug Administration approved its 100 Hertz excimer laser for vision correction, which will be used as part of its Zyoptix personalized laser vision correction system in refractive surgery. The laser operates at twice the speed of the Bausch & Lomb system currently on the market in the United States, in both standard and custom modes. The laser is expected to become commercially available by July.
British health organization issues guidance on laser eye surgery
The National Institute for Health and Clinical Excellence (NICE) last week released a final draft of a document that considers the safety and efficacy of laser eye surgery. The guidance does not recommend laser eye surgery be offered to patients routinely because most eye problems can easily be corrected by wearing spectacles or contact lenses.
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Novel Treatment Can Restore Good Vision in Patients With Stage 4 DLK
Brian R. Will, MD
Brian R. Will, MD, presented a paper at the American Society of Cataract and Refractive Surgery meeting earlier this month that contradicts widely-held theories about the pathophysiology of this feared complication of LASIK.
Dr. Will said that Stage 4 diffuse lamellar keratitis – typically believed to be associated with corneal melts, permanent scarring and disastrous visual outcome – is caused by highly localized tissue edema, not tissue necrosis. This misunderstanding has lead to ineffective management techniques and poor outcomes for patients, he said. His approach is to begin immediate treatment with a hyperosmotic protocol that includes managing the edema, aggressively treating flap macrostriae and, if necessary, treating residual refractive error.
He described his experience with six patients (eight eyes—six myopes and two mixed astigmats) who developed Stage 4 diffuse lamellar keratitis post-LASIK. The series represents every case Dr. Will treated over the past four years. All eyes presented with vision loss, corneal opacification and flap macrostriae between five and eight days after surgery. Two of the myopes presented with bilateral Stage 4 DLK with vision loss ranging from 20/60 to count fingers.
Within a few months under Dr. Will’s treatment protocol, every patient recovered to 20/15 or 20/20 vision and their corneas appeared indistinguishable from routine LASIK cases with no scarring or microstriae. No eye demonstrated stromal loss. Only four of eight eyes underwent conventional excimer laser enhancement procedures. No patient complained of glare, halos or other visual disturbances.
Interestingly, all eyes in Dr. Will’s case series underwent treatment with the IntraLase femtosecond laser, which he says may increase the risks for DLK if improper settings are used (Dr. Will has a financial interest in IntraLase). When energy, spot and line separation are not optimized, the laser causes more keratocyte injury, leading to edema and inflammation.
His technique is based on what he observed from his first bilaterally affected patient. The stromal bed was normal, which contradicted what he had been taught: that the corneal tissue would be necrotic.
Dr. Will suggests that Stage 4 DLK is caused by keratocyte dysfunction which creates decreased interstitial fluid pressure, frank focal stromal edema, full thickness flap macrostriae and hyperopic shift.
He recommends aggressively treating with hyperosmotics immediately upon presentation. Initial therapy includes preservative free glycerol 99.5 percent at one drop per 10 minutes over 30 minutes. The patient should then be placed on hourly Muro 128 (sodium chloride 5 percent, Bausch & Lomb, Rochester, N.Y.) drops and Muro ointment at night. Preservative-free Acular LS (Allergan, Irvine, Calif.) four times daily, an anti-inflammatory drug to suppress inflammatory cytokine synthesis, and 1000 mg of vitamin C daily may also be beneficial. As the edema and refractive error improve the Muro can be tapered while monitoring for recurrence of the edema.
Patients should receive Muro three to four times daily for three to four months if they can tolerate the stinging. The initial glycerol treatment will quickly lower the edema and improve patients’ outlook, which induces better treatment compliance. The Muro should be titrated based on the resulting correction, the amount of swelling and how willing the patient is to stick with the regimen. Because the drops burn when they go in, patients can’t be kept on hourly Muro indefinitely.
Macrostriae can be treated at six to eight weeks postoperatively, a sufficient time to allow the cornea to recover control over interstitial fluid dynamics while not allowing the flap folds to become too permanent. In treating the macrostriae it is critical to mechanically remove all of the epithelium from the central cornea where the folds and macrostriae occur with a 64 blade prior to lifting the flap. The flap is then lifted from the bed completely before it is again repositioned on the stromal bed. No hyperosmotic or hypotonic agents, heat, ironing or suturing is needed or advised. None of the eyes in this study had any sutures placed to remove macrostriae. However, once the flap is repositioned it must be stretched with a dry merocel for several minutes. Then apply a bandage contact lens and a drop of glycerol immediately after surgery. The patient should be examined at the slit lamp before discharge to assure the macrostriae are resolved.
Dr Will said the biggest mistake most surgeons make is failing to completely remove all epithelium over the macrostriae, including the epithelium in the flap folds prior to stretching the flap. Any remaining epithelium will bind the fold so that even aggressive stretching or suturing will be ineffective in removing the fold. If once the flap is reepithelialized and the microstriae are not satisfactorily resolved, the procedure can be repeated again a few weeks later. Removing the fold is very important to eliminate vision loss due to optical imperfections, and it allows the endothelial pump to better deterges the flap. If the flap has full thickness folding, the gap in the interface creates a barrier to the movement of fluid from the flap to the stromal bed and unnecessarily prolongs flap edema. To ensure flap hydration returns to normal levels, attention must be paid to the macrostriae.
Attempts to stretch out the folds in the first few weeks post-op will only result in recurrence of the swelling and the macrostriae. The keratocytes in the stroma must be allowed to recover before there is an attempt to remove the flap macrostriae. This will allow the keratocytes to maintain a more homeostatic control over the interstitial fluid pressure. The timing of flap stretching is critical because if the surgeon waits too long and the folds are left in place they will become permanent and the eye will stay hyperopic, exhibit irregular and induced astigmatism and exhibit loss of best-corrected visual acuity.
When the edema and flap folds are correctly treated, the hyperopic shift and associated optical aberrations will resolve quickly and completely.
Brian R. Will, MD, is an assistant clinical professor of ophthalmology at the Loma Linda University School of Medicine in Loma Linda, Calif.
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