Two-year outcomes of intrastromal corneal ring segments for the correction of myopia.

OBJECTIVE: To evaluate the safety and efficacy of Intrastromal Corneal Ring Segments (ICRS) for the correction of myopia. DESIGN: Nonrandomized, comparative trial. PARTICIPANTS: Patients enrolled in the United States Food and Drug Administration phase II and phase III clinical trials of the ICRS had best spectacle-corrected visual acuity (BSCVA) of 20/20 or better, myopia of -1.00 to -3.50 diopters (D), and a cylindrical correction of 1.00 D or less as measured by manifest refraction. INTERVENTION: Surgical correction of myopia with an ICRS. MAIN OUTCOME MEASURES: Efficacy was assessed by predictability of refractive outcome (deviation from predicted cycloplegic refraction spherical equivalent), stability of refractive effect, and postoperative uncorrected visual acuity. Safety was assessed by adverse events, maintenance or loss of preoperative BSCVA, and induced manifest refraction cylinder. RESULTS: Four hundred fifty-two patients were enrolled at 11 investigational sites in both studies. Of the 454 surgical attempts, 449 received an ICRS in one eye (0.25, 0.30, and 0.35 mm in 148, 151, and 150 eyes, respectively). First surgeries were attempted in 452 patients. An ICRS was successfully implanted in 447 initial eyes, and 5 surgeries were discontinued. Of the five discontinued surgeries, three patients subsequently exited from the study, and two patients went on to have the ICRS implanted in the second eye, bringing the total number of successful implants to 449 patient eyes. Month 24 postoperative follow-up was completed on 358 patients (80%). At month 24, 328 of 354 eyes (93%) were within +/-1.00 D of predicted refractive outcome. Refraction changed by 1 D or less in 97% of eyes (421/435) between 3 and 6 months after implantation and in 99% (343/348) between months 18 and 24. Before surgery, 87% of eyes (390/448) saw worse than 20/40 uncorrected; 24 months after surgery, 55% of eyes (196/358) saw 20/16 or better, 76% (271/358) saw 20/20 or better, and 97% (346/358) saw 20/40 or better. Although two eyes (2/358; 0.5%) lost two or more lines of BSCVA at 24 months; visual acuity in both was 20/20 or better. Intraoperative complications included anterior corneal surface perforation (three eyes) and anterior chamber perforations (two eyes, one during an attempted exchange procedure); all healed spontaneously without suturing and without loss of BSCVA. The ICRS was repositioned in five eyes to increase correction. Postoperative complications in one eye each were infectious keratitis, shallow segment placement, and loss of two lines of BSCVA at two or more consecutive examinations (subsequently regained). CONCLUSIONS: The ICRS safely, predictably, and effectively reduced or eliminated myopia of -1.00 to -3.50 D. The refractive effect was stable over time.

Astigmatism management: ablation patterns.

Treatment of astigmatism is possible with the excimer laser. Results with this technology are more predictable and accurate than with incisional techniques. Ablation profiles differ for the various types of astigmatism, and the best approach is the one in which the least amount of tissue is removed from the cornea. Surgical success requires appropriate preoperative counseling, careful preoperative measurements, and meticulous intraoperative technique. Reported outcomes are excellent and future developments will lead to even better results.

Refractive surgery in the new millennium.

As we stand at the threshold of a new millennium, perhaps nowhere else in the field of ophthalmology is there such a feeling of excitement, enthusiasm, and anticipation as in the subspecialty of refractive surgery. What was once considered an experimental hobby, dabbled in by a few rogue physicians, has now gained a level of respect among patients and ophthalmologists that has surprised even its most vocal critics.

Intrastomal corneal ring segments: reversibility of refractive effect.

PURPOSE: To evaluate the reversibility of refractive effect following removal of the ICRS (intrastromal corneal ring segments; Intacs). METHODS: Data from 34 eyes from which ICRS were removed during United States FDA Phase II and III clinical trials were evaluated with regard to segment size, loss or change of best spectacle-corrected visual acuity (BSCVA), any change of uncorrected visual acuity (UCVA), manifest spherical equivalent refraction, manifest cylinder refraction, stability of manifest cylinder refraction, and subjective visual symptoms. RESULTS: Out of 725 initial or contralateral eyes placed with the ICRS during Phase II and III clinical trials, segments were removed from 34 eyes (4.7%). Other than one (1/725, 0.1%) safety related ICRS removal, 30/725 (4.1%) were due to visual symptoms. ICRS removal was accomplished under topical anesthesia without complications in all eyes. The mean length of time the segments remained in the cornea after initial surgery was 10.3 +/- 5.4 months. At 3 months after ICRS removal, 21 eyes had monitored data available and were within +/-1 line or 10 letters of their preoperative BSCVA. Twenty eyes (20/21, 95%) returned to within +/-1.00 D of their preoperative manifest spherical equivalent refraction. All eyes had a stable refraction at the 3-month examination after removal, and a manifest spherical equivalent refraction within +/-1.00 D of their 1-month examination after removal. Nineteen eyes (19/21, 90%) returned to within +/-2 lines and 16 eyes (16/21, 76%) returned to within +/-1 line of preoperative UCVA. CONCLUSION: The ICRS (Intacs) was easily and safely removed, and eyes returned to preoperative refractive status within 3 months.

Corneal thickness and visual acuity after phacoemulsification with 3 viscoelastic materials.

PURPOSE: To determine whether differences exist in visual acuity and corneal thickness after phacoemulsification using various viscoelastic substances. SETTING: Phillips Eye Institute, Minneapolis, Minnesota, USA. METHODS: Fifty patients having routine phacoemulsification cataract extraction and intraocular lens implantation by a single surgeon using the same technique were randomly assigned to receive intraoperative administration of 1 of 3 viscoelastic substances: Amvisc Plus(R) (sodium hyaluronate 1.6%), OcuCoat(R) (hydroxypropyl methylcellulose 2%), or Viscoat(R) (chondroitin sulfate 4%-sodium hyaluronate 3%). Visual acuity and corneal thickness on the first postoperative day were compared between groups. RESULTS: Patients with a best corrected visual acuity (BCVA) of 20/40 or better 1 day postoperatively had significantly thinner corneas (596 microm) than those with a BCVA worse than 20/40 (639 microm). There were no differences in postoperative BCVA or percentage increase in central corneal pachymetry among the 3 viscoelastic groups. CONCLUSION: Viscoat, Amvisc Plus, and OcuCoat were comparable in their ability to produce clear corneas and good vision after routine phacoemulsification.

Early results of hyperopic and astigmatic laser in situ keratomileusis in eyes with secondary hyperopia.

PURPOSE: To assess the safety and efficacy of laser in situ keratomileusis (LASIK) for secondary hyperopia and hyperopic astigmatism and to develop a VISX STAR S2 LASIK nomogram (VISX Inc., Santa Clara, CA) for consecutive hyperopia after prior myopic refractive surgery. DESIGN: Prospective, nonrandomized, self-controlled interventional study. PARTICIPANTS: Thirty patients with consecutive hyperopia or hyperopia and astigmatism after LASIK, photorefractive keratectomy, automated lamellar keratoplasty, or radial keratotomy. INTERVENTION/METHODS: Prospective evaluation of LASIK in 30 secondary eyes with fogged manifest sphere from +0.5 to +6.0 diopters (D) and cylinder from 0 to +5.0 D. MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), and spherical equivalent (SE). RESULTS: Mean manifest SE was +1.73 +/- 0.79 D before surgery, -0.13 +/- 1.00 D at 6 months after surgery, and -0.18 +/- 1.08 D at 1 year after surgery. At 6 months, 84% of patients with secondary hyperopia had UCVA of 20/40 or better; 76% were within +/-1 D of emmetropia. At 1 year, 85% had UCVA of 20/40 or better and 85% were within +/-1 D of emmetropia. No patients with secondary hyperopia lost 2 or more lines of BCVA at 1 year. Complications included intraoperative bleeding (3.3%), intraoperative epithelial defect (3.3%), transient interface debris (3.3%), significant dry eye (3.3%), blood in interface (3.3%), irregular astigmatism (6.7%), slight decentration (6.7%), trace haze (6.7%), or mild epithelial ingrowth not requiring removal (3.3%). CONCLUSIONS: These early data suggest that LASIK for consecutive hyperopia from +0.5 to +5.50 D and astigmatism from 0 to +2.75 D using the VISX STAR S2 benefits from a nomogram adjusted for preoperative refraction, age, and prior refractive surgery, and is safe and effective.

Diffuse lamellar keratitis: diagnosis and management.

With the volume of laser in situ keratomileusis procedures growing exponentially, ophthalmologists and other eye-care providers are becoming aware of an uncommon postoperative condition, diffuse lamellar keratitis, that can affect an otherwise ideal outcome. We present our strategy for diagnosing and managing this syndrome, developed from experience in a high-volume refractive surgical practice. Understanding the time course of the disease, along with proper identification, staging, and intervention, can help eliminate visual loss associated with this condition.

Laser in situ keratomileusis after intracorneal rings. Report of 5 cases.

PURPOSE: To examine the results of laser in situ keratomileusis (LASIK) after removal of intracorneal ring (ICR) segments. SETTING: Active refractive surgery practice. METHODS: The effect of ICR (0.45 mm) placement, the rapidity of refractive recovery after explantation, and the results of subsequent LASIK were examined in 5 eyes. RESULTS: Four eyes developed induced astigmatism after ICR implantation. In 2 of these eyes, retained astigmatism was evident by manifest refraction or corneal topography even after ICR explantation. In 1 eye, the ICR procedure was aborted because of an intraoperative complication. All 5 eyes had subsequent uneventful LASIK. CONCLUSIONS: Intracorneal rings can induce astigmatism that may be retained even after explantation. Careful wound manipulation may reduce the incidence of this complication. Laser in situ keratomileusis after ICR removal appears to be safe and effective.

Phacoemulsification and modern cataract surgery.

The techniques and results of cataract surgery have changed dramatically during the past three decades. In the USA, we have moved from intracapsular cataract extraction as the preferred technique to almost exclusively extracapsular techniques. Smaller incisions have become the standard, with phacoemulsification now being the method of choice for most surgeons. Along with these advances have come improved intraocular lens materials and designs, especially well suited for use with smaller incisions. Phacoemulsification as a method to remove the cataractous lens was first proposed more than 20 years ago. Advances in techniques and equipment have led to a dramatic increase in the popularity of phacoemulsification with increased safety and efficiency. Viscoelastic agents have been developed synchronously with modern phacoemulsification techniques, playing an integral role in the success of this new technology. Improved surgical techniques for removing the anterior lens capsule have decreased the incidence of both intraoperative and postoperative capsular complications. Nucleus removal, formerly performed primarily in the anterior chamber, is now performed in the posterior chamber, decreasing damage to the corneal endothelium. Improved wound construction allows many wounds to be left unsutured, and smaller wounds allow shorter recovery time and greater intraoperative control and safety. Intraocular lenses can have smaller optic sizes and still maintain accurate centration. Foldable intraocular lenses can take advantage of the smaller incision, even further shortening the time to visual recovery. Continual evolution of this technology promises to further improve patient outcomes after cataract surgery.

Adjustability of refractive effect for corneal ring segments.

PURPOSE: To evaluate the safety and efficacy of adjustability of the refractive effect of intrastromal corneal ring segments (ICRS, Intacs). METHODS: Data from four patients who had their initial Intacs removed and exchanged for new Intacs of different thickness sizes during a United States Food and Drug Adminstration Phase II clinical trial were evaluated with regard to segment size, reasons for exchange, duration within the cornea before exchange procedure, loss or change of spectacle-corrected visual acuity, change of uncorrected visual acuity, manifest refraction, cycloplegic refraction, topography after exchange, and stability of refraction. RESULTS: The exchange procedure was performed in two patients due to undercorrection and in two for overcorrection. The length of time the segments remained in the cornea after initial surgery varied from 6 to 15 months (mean, 10.25 +/- 4.03 mo). The most recent examination occurred between 4 to 18 months (mean, 10.0 +/- 6.32 mo) following the exchange procedure and showed improved uncorrected visual acuity with a range from 20/16 to 20/20 and a gain of 2 to 7 lines of uncorrected visual acuity compared to baseline. No eyes lost any lines of spectacle-corrected visual acuity following the exchange procedure and all preserved their preoperative spectacle-corrected visual acuity of 20/16. The intended refractive correction was achieved in the first few days of the exchange procedure and remained stable. CONCLUSION: In these four eyes that were over- or undercorrected after initial Intacs placement, segment thickness sizes were exchanged after 6, 8, 12, and 15 months without complication and with final uncorrected visual acuities of 20/16 to 20/20.

Six-month results of hyperopic and astigmatic LASIK in eyes with primary and secondary hyperopia.

PURPOSE: To assess the safety and efficacy of laser in situ keratomileusis (LASIK) for hyperopia and hyperopic astigmatism and develop a LASIK nomogram for primary hyperopia or hyperopia secondary to myopic refractive surgery using the VISX STAR S2. METHODS: Prospective evaluation of LASIK in 46 primary eyes and 29 secondary eyes with fogged manifest sphere from +0.5 diopters (D) to +6.0 D and cylinder from 0 to +5.0 D. RESULTS: Mean manifest spherical equivalent (SE) in patients with primary hyperopia was +2.50 D +/- 0.93 preoperatively and +0.70 D +/- 1.19 at 6 months. At 6 months, 79% of primary hyperopes had uncorrected visual acuity (UCVA) of 20/40 or better; 63% were within +/- 1 D of emmetropia. One primary hyperope lost 2 lines of best spectacle-corrected vision (BCVA) at 1 month. Complications included transient epithelial defect (6.5%), epithelial cells in the interface (4.3%), diffuse lamellar keratitis (4.3%), haze (2.2%), and mild irregular astigmatism (2.2%). In those with secondary hyperopia, mean manifest SE was +1.70 D +/- 0.82 preoperatively and -0.27 D +/- 0.95 at 6 months. At 6 months, 83% of secondary hyperopes had UCVA of 20/40 or better; 74% were within +/- 1 D of emmetropia. No secondary hyperope lost > or = 2 lines of BCVA. Complications included intraoperative bleeding (3.4%), intraoperative epithelial defect (3.4%), transient interface debris (3.4%), significant dry eye (3.4%), blood in interface (3.4%), irregular astigmatism (6.9%), slight decentration (6.9%), trace haze (6.9%), mild epithelial ingrowth not requiring removal (3.4%), or corneal irregularity (3.4%). CONCLUSION: These early data suggest that LASIK for hyperopia from +0.5 to +6 D and astigmatism from 0 to +5 D using the VISX STAR S2 benefits from a nomogram adjusted for preoperative refraction, age, and prior refractive surgery and is safe and effective. Patients with secondary hyperopia achieved more correction than those with primary hyperopia, although the accuracy and predictability of LASIK in both groups has improved with the nomogram adjustments.

What every general practitioner should know about the laser vision correction revolution.

With tens of millions of Americans potential candidates for laser vision correction (LVC), increasing numbers of patients are asking their general practitioners for advice and information on this revolutionary procedure. The following article will provide general practitioners a broad view of LVC, including valuable data and resources to share with their patients. The latest techniques in LVC--including step-by-step descriptions of the procedures and clinical outcomes--are outlined in detail, along with what steps MCOs are taking to address this growing trend.