One year results of European Multicenter Study of intrastromal corneal ring segments. Part 2: complications, visual symptoms, and patient satisfaction

PURPOSE: To assess intraoperative and postoperative complications, visual symptoms, and patient satisfaction after implantation of intrastromal corneal ring segments (ICRS, KeraVision, Inc.) for the correction of myopia and to demonstrate the reversibility and adjustability of refractive corrections with this method. SETTING: Twelve European investigational sites. METHODS: Patients with myopia of -1.0 to -6.0 diopters (D) were assigned to receive 1 of 5 ICRS thicknesses (0.25, 0.30, 0.35, 0.40, or 0.45 mm). Complications and visual symptoms were noted, and patient satisfaction was assessed at each postoperative visit (1 and 7 days and 1, 2, 3, 6, and 12 months). Refractive data were assessed after removal or exchange of the ICRS. RESULTS: Of 163 eyes of 110 patients enrolled, 159 eyes of 107 patients were implanted with an ICRS (52 patients had bilateral implantation). Intraoperative complications occurred in 2% of eyes (4/163 eyes in 3 patients) that were withdrawn from the study: 3 eyes had anterior surface perforations and 1 had a posterior microperforation into the anterior chamber. Most patients had no visual symptoms at 12 months; symptoms usually occurred rarely or sometimes and were mild in severity. At 12 months, good or excellent patient satisfaction was reported for 94% of eyes. Twelve ICRSs (8%) were removed, mainly because of undercorrection and induced astigmatism, and 2 were exchanged. All eyes were within +/-1.00 D of the preoperative manifest refraction spherical equivalent. CONCLUSIONS: The ICRS was safe for correction of low to moderate myopia. Severe postoperative visual symptoms were rare, and patient satisfaction was high. The refractive correction was largely reversible.     

Late bacterial keratitis after intracorneal ring segments (Ferrara ring) insertion for keratoconus

PURPOSE: To report a case of late bacterial keratitis after intrastromal corneal ring segments (ICRSs; Ferrara ring; Ferrara Ophthalmics, Belo Horizonte, Brazil). METHODS: Review the clinical findings in a 42-year-old woman with bilateral keratoconus who underwent implantation of Ferrara ring segments in her left eye and 4 months later presented with corneal infiltrates and hypopyon. Bacterial staining, culture, and antibiotic sensitivities were done. Medical treatment and rings explantation were performed. RESULTS: The cultures revealed growth of vancomycin-oxacillin sensible coagulase-positive Staphylococcus aureus. Treatment with topical moxifloxacin, topical imipenem, and systemic intravenous and topical vancomycin was kept for two weeks. Corneal inflammation and hypopyon resolved, leaving a minimal residual leucoma. CONCLUSIONS: Infectious keratitis is an uncommon complication of ICRS and it may be late in presentation, even months after implantation. Importance of patient education about alarm symptoms and the need for long-term close postoperative follow-up cannot be underestimated. If a change in surgical technique, i.e., suturing the incision, has an influence in this complication's incidence, it will require further studies.     

One year results of European Multicenter Study of intrastromal corneal ring segments. Part 1: refractive outcomes

PURPOSE: To assess the efficacy, predictability, stability, and safety of correcting myopia with intrastromal corneal ring segments (ICRS, KeraVision, Inc.). SETTING: Twelve European investigational sites. METHODS: Patients with myopia of -1.0 to -6.0 diopters (D) and best spectacle-corrected visual acuity (BSCVA) of 20/20 or better (except in 3 eyes) were assigned to receive 1 of 5 ICRS thicknesses (0.25, 0.30, 0.35, 0.40, or 0.45 mm). Efficacy was assessed by postoperative uncorrected visual acuity (UCVA), predictability of refractive outcome (deviation from predicted cycloplegic refraction spherical equivalent), and stability of refractive effect (manifest refraction spherical equivalent [MRSE]). Safety was assessed by maintenance or loss of preoperative BSCVA and induced manifest refraction cylinder. Measurements were made preoperatively and 1 and 7 days and 1, 2, 3, 6, and 12 months postoperatively. RESULTS: One hundred fifty-nine ICRSs were implanted in the eyes of 107 patients (52 patients had bilateral implantation). Preoperatively, UCVA was worse than 20/40 in 98% of eyes (155/159); 12 months postoperatively, it was 20/20 or better in 63% of eyes (83/132) and 20/40 or better in 96% (127/132). Predicted refractive corrections for each ICRS thickness generally correlated with achieved corrections. At 12 months postoperatively, 90% of eyes (124/138) were within +/-1.00 D of plano (MRSE). Two or more lines of BSCVA were lost in 6% of eyes (8/135); all 8 eyes had BSCVAs of 20/25 or better. CONCLUSION: The ICRS safely, effectively, and predictably reduced or eliminated low to moderate myopia. Refractive correction was stable through the 12 month follow-up.     

One-year results of intrastromal corneal ring segment implantation (KeraRing) using femtosecond laser in patients with keratoconus

PURPOSE: To report the results of intrastromal corneal ring segment [ICRS] (KeraRing; Mediphacos, Belo Horizonte, Brazil) implantation using a femtosecond laser (IntraLase Corp, Irvine, California, USA) in keratoconic patients. DESIGN: Retrospective, noncomparative, interventional study. METHODS: Thirty-two keratoconic patients (50 eyes) who underwent ICRS insertion using a femtosecond laser for channel creation and completed at least one year of follow-up were included in this study. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, topographic findings, and adverse events were assessed. RESULTS: No intraoperative complications were demonstrated in this series of patients. At the first postoperative day, segment migration to the incision site was seen in three eyes (6%; early postoperative complication). To avoid melting, we repositioned the migrated segment away from the incision site. Serious second migration was not seen and we did not need to reposition any segment again. At the last postoperative examination, there was a statistically significant reduction in the spherical equivalent refractive error compared with that observed at the examination before implantation (mean +/- standard deviation, -5.62 +/- 4.15 diopters [D; range, -23.62 to 0.50 D] to -2.49 +/- 2.68 D [range, -11.12 to 3.5 D]; P < .001). The UCVA before implantation was 20/40 or worse in 47 eyes (94%; range, counting fingers to 20/30), whereas at the last follow-up examination, 14 (28%) of 50 eyes had a UCVA of 20/40 or better (range, counting fingers to 20/25). Nine eyes (18%) maintained the preimplantation BSCVA, whereas 39 eyes (68%) experienced a BSCVA gain of one to four lines at the last follow-up examination. Only in two eyes (4%; two patients) with advanced keratoconus (stage III) was there a decrease of up to two lines. Despite this deterioration in BSCVA, the patients did not want to remove the ICRSs, because there was an increase of UCVA. No late postoperative complications were observed during the follow-up period. CONCLUSIONS: ICRS (KeraRing) implantation using femtosecond laser for tunnel creation is a minimally invasive procedure for improving visual acuity (both UCVA and BSCVA) in keratoconic patients.     

Aspergillus fumigatus keratitis following intracorneal ring segment implantation

ABSTRACT: BACKGROUND: Fungal keratitis has been rarely reported following intracorneal ring segment (ICRS) inmplantation. This paper aims to report a case of fungal keratitis with aspergillus fumigatus following ICRS implantation for correction of keratoconus. METHODS: A retrospective chart review was done. Data including demographics, clinical history and presentation, microbiological analysis as well as clinical management were recorded. RESULTS: A 34 year old male presented with pain, photophobia, redness and decreased vision in his right eye ten days after ICRS implantation for correction of keratoconus. Slit-lamp examination showed chemosis, ciliary injection, corneal abcess with ill defined edges and hypopyon. Microbiological analysis and culture of the corneal scrapes were positive for aspergillus fumigatus. The patient did not respond to medical treatment and ended up with corneal transplantation. CONCLUSION: Although rare, fungal keratitis is a serious vision threatening complication that can complicate intrastromal ring implantation. Prompt and aggressive treatment is essential to prevent irreversible reduction of vision.     

Clinical outcomes of management of posterior capsule rupture with air bubble techniques

AIM: To evaluate the clinical outcomes after implantation of a new intrastromal corneal ring segment associated with photorefractive keratectomy (PRK) to correct high myopia (ICRS HM) in patients with thin corneas. METHODS: We evaluated 42 eyes of 23 patients that had ICRS HM implantation followed by PRK. The mean age of patients was 29.1±7.12y (range 18 to 40 years old). Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry, spherical equivalent, pachymetry, and aberrometry were compared using ANOVA with repeated measurements assessed preoperatively and at last follow-up visit after the procedures. The refractive predictability and simulated/real corneal ablation were also assessed. RESULTS: The mean follow-up time after PRK was 6.8±1.6mo. The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK. The mean preoperative BCVA was 20/25 (range from 20/40 to 20/20) and remained unchanged after ICRS HM implantation. Following the PRK the mean BCVA was 20/25 (range from 20/40 to 20/20). The mean spherical equivalent decreased from -7.25±1.12 (range -5.00 to -9.00) preoperatively to -3.32±1.0 (range -2.00 to -5.00) postoperatively (P<0.001) after ICRS HM, ICRS implantation and decreased from -2.44±1.51 preoperatively to 0.32±0.45 (range -0.625 to 0.875) postoperatively (P<0.001) after PRK. The change in BCVA and topographic astigmatism was statistically significant (P<0.0001). CONCLUSION: ICRS HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.     

Experimental imaging of intracorneal ring segments with optical coherence tomography

PURPOSE: To investigate the imaging of corneal structures with optical coherence tomography (OCT) after implantation of intracorneal ring segments (ICRS). METHODS: In an experimental study with six porcine eyes, qualitative and quantitative imaging with corneal OCT using a wavelength of 1310 nm after implantation of ICRS was performed. The optical results were compared with light microscopy of the histological sections. RESULTS: In corneal OCT, the ICRS revealed marked hyporeflective intrastromal areas, which correlated well with macroscopic and microscopic findings. Corneal OCT enabled precise images of the incision depth for the implantation of ICRS, and the exact intrastromal segment position. CONCLUSIONS: Noncontact slit lamp-adapted corneal optical coherence tomography could be employed to clinically monitor corneal changes after implantation of ICRS, evaluate the depth of the segments to correlate refractive changes, and quantify the stromal wound healing response.     

Laser in situ keratomileusis and intrastromal corneal ring segments for high myopia. Three-step procedure

We describe a surgical procedure to correct relatively high myopia in patients with thin corneas. The technique combines laser in situ keratomileusis (LASIK) and intrastromal corneal ring segment (ICRS) implantation. The 3-step procedure comprises ICRS channel formation, LASIK, and segment insertion. The technique was used in 2 eyes of 2 patients with low pachymetry values and high myopia. One patient achieved an uncorrected visual acuity (UCVA) of 20/30 and a best spectacle-corrected visual acuity (BSCVA) of 20/25 with +0.50 -1.75 x 101. The other patient achieved a UCVA of 20/30 and a BSCVA of 20/20 with +0.75 -1.50 x 80.     

Implantable collamer lenses after intracorneal ring segments for keratoconus

To report the clinical characteristics and visual outcomes of patients with keratoconus treated with posterior chamber phakic intraocular lenses after implantation of intracorneal ring segments (ICRS). This retrospective study included 11 eyes of eight patients diagnosed with keratoconus treated with ICRS and posterior chamber phakic intraocular lenses. The preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), preoperative and postoperative keratometric data, manifest refraction and spherical equivalent were recorded. No complications were observed. At 38.18?±?18.7?months of follow-up, the mean spherical error was -0.06?±?0.46 D (+0.75 to -0.75 D) and cylindrical error of -1.22?±?0.65 D (-0.25 to -1.5 D). The preoperative spherical equivalent was -10.52?±?5.88 D (-3.12 to -22.75 D) and the postoperative spherical equivalent was -0.68?±?0.45 D (0 to -1.25 D), p?相似文献   

Intrastromal corneal ring segments in a patient with previous laser in situ keratomileusis

PURPOSE: Intrastromal corneal ring segments (ICRS; Intacs) were inserted in a patient with residual myopia of -3.375 D (spherical equivalent) 10 months after laser in situ keratomileusis (LASIK). METHODS: A standard intrastromal corneal ring segment implantation technique was used with the addition of intraoperative ultrasonic pachymetry in 4 quadrants at the 7-mm zone to insure adequate stromal thickness for segment insertion. RESULTS: Four months after ICRS surgery and 14 months after LASIK, the patient had uncorrected visual acuity of 20/20 and a cycloplegic refraction of plano -1.00 x 23 degrees. CONCLUSION: Implantation of intrastromal corneal ring segments in an eye with previous LASIK resulted in additional corneal flattening with a decrease in residual myopia and improved uncorrected visual acuity.     

Corneal infections after implantation of intracorneal ring segments

PURPOSE: To report risk factors, clinical course, and outcome in patients with infectious keratitis following implantation of intracorneal ring segments (ICRS). METHODS: The records of 8 patients with culture-proven infectious keratitis after ICRS (Ferrara or Intacs) implantation were retrospectively reviewed. Age, gender, corneal findings, ocular abnormalities, the condition that led to ICRS implantation, immediate prior use of a contact lens, elapsed time between implantation and the onset of symptoms, previous medications, and systemic disorders were noted. RESULTS: Culture-positive infectious keratitis developed in 7 eyes of 7 patients (2 men and 5 women) with a mean age of 35 years who underwent Ferrara implantation for the treatment of keratoconus and in a 29-year-old man who underwent Intacs implantation for correction of low myopia. Contact lens use, diabetes, and trauma were factors possibly associated with the risk of infection in three cases. Microorganisms, identified in all cases, included Staphylococcus aureus, Streptococcus viridans, Streptococcus pneumoniae, Pseudomonas sp, Nocardia sp, Klebsiella sp, and Paecylomices sp. Onset of symptoms of infection varied from less than 1 week to 22 months postoperatively, depending on the infecting organism. CONCLUSIONS: Infectious keratitis following ICRS implantation is a sight-threatening complication for which early recognition and rapid institution of appropriate treatment may result in a better visual outcome.     

Confocal microscopy after implantation of intrastromal corneal ring segments

OBJECTIVE: Confocal in vivo real-time microscopy was used to study the corneal morphologic features in eyes after Intrastromal Corneal Ring Segments (ICRS; now called KeraVision INTACS, KeraVision, Inc., Fremont, CA) implantation. DESIGN: Noncomparative, interventional case series. PARTICIPANTS: The authors performed confocal real-time microscopy on a total of 21 eyes from 11 patients. Seventeen eyes from 10 patients (five female, five male; mean age 32.3 years; range 22-42 years) underwent uncomplicated ICRS surgery to correct myopia and were examined after surgery (average 8.6 months; range 2-15 months). Three patients had the ICRS implanted into only one eye, and those eyes were compared with the untreated fellow eyes. One eye of another patient was examined 1 and 6 months after ICRS removal. INTERVENTION: Flying slit-confocal microscopy was performed with water immersion objectives in the corneal center and near the nasal or temporal ICRS. Corneal optical sections were recorded in real time without further digital processing and were reviewed frame by frame. MAIN OUTCOME MEASURES: Video frames selected from all corneal layers were evaluated qualitatively and quantitatively. RESULTS: In the central cornea, we found normal morphologic features at all layers. In peripheral sections, epithelial cells with highly reflective nuclei in the basal cell layer were observed in six of 17 eyes (35%) implanted with ICRS. We found an intact corneal nerve plexus and undisturbed corneal endothelium immediately underneath the ICRS. Around the ICRS, moderate fibrosis was seen. In one eye, linear structures in bamboo-like orientation were detected after ICRS removal in the last keratocyte layer underneath the collapsed tunnel. CONCLUSIONS: Whereas the central corneal zone appears unchanged, the corneal stroma adjacent to the ICRS displays a slight, but distinct, activation of wound healing. Epithelial cells with highly reflective nuclei in this region may be an indicator for an increased biologic stress caused by the device.     

Ex- und Reimplantation von intrakornealen Ringsegmenten bei progressivem Keratokonus mit Hilfe des Femtosekundenlasers Femtec

Implanted intracorneal ring segments (ICRS) led to a steepening of the cornea and an increase in visual deterioration. Thanks to the femtosecond laser, we can now prepare implantation tunnels intrastromally with mum precision. Therefore, we explanted the original ring segments. After a waiting period, we prepared a second implantation tunnel above the first using the femtosecond laser and implanted new ICRS. The conus was considerably flattened and shifted, and vision improved significantly.     

First results of myopia correction with intracorneal ring segments (ICRS)

PROBLEM: The Implantation of intracorneal ring segments (ICRS) offers the possibility of reversible, refractive surgery for correction of lower myopia up to -5.0 D. We report our first results 1 year after implantation of ICR segments. PATIENTS AND METHODS: From April 1997 to August 1998 we implanted ICRS in 48 eyes of 31 patients (12 male, 19 female) to correct myopia. The preoperative refraction (spherical equivalent) was between -1.0 and -5.0 D (astigmatism < 1.0 D). The average age was 34.0 years (range 19-48 years). ICRS implantation was performed in peribulbar anaesthesia. All operations were done by the same surgeon. RESULTS: The average follow-up was 10 months (ranges 1-12 months). After 6 months the deviation from the target refraction of all eyes was < 1.5 D; 26 of 27 eyes (96.3%) showed a deviation of < or = 1.0 D. Six months after surgery, 18 of 27 eyes (66.6%) showed an uncorrected visual acuity of 20/20 or better, 23 of 26 eyes (88.4%) showed 20/25 or better, and 25 of 26 eyes (96.2) 20/40 and better. Only 1 of 16 eyes showed an uncorrected visual acuity of 20/50. In all eyes, the best-corrected visual acuity was 20/20 or better. In 2 eyes an ICRS exchange and implantation of a thicker ring was necessary because the target refraction could not be achieved with the first implanted ring. In 2 eyes an ICRS reposition was done to optimize the location of the ring within the cornea. In 4 eyes we explanted the ring due to double vision (1 x) and distorted vision (3 x) caused by induced astigmatism. After explantation the preoperative refraction (+/- 0.15 D) was reached within 1 to 1.5 months. There was no regression after 6 months (n = 27) or after 1 year (n = 7). CONCLUSION: Our 1-year results of ICRS implantation show that myopia correction with the advantage of reversibility and lower complication rate is possible by this refractive surgical method. Ring exchange and explantation are possible. Earlier postoperative complaints like photophobia, unstable visual acuity or discomfort usually disappear rapidly. The decision of 95.0% of the patients to have ICRS implantation also into the second eye shows the high degree of satisfaction.     

Toric Artisan after transepithelial topography-guided photorefractive keratectomy for higher-order aberrations following intrastromal corneal ring segments in keratoconus – Trioptics

We report a case of a 40-year-old female with keratoconus and high myopia who had previous ICRS implantation in both eyes (OU) and was intolerant to contact lenses. Manifest refraction was - 8.50 - 1.50 × 95 (20/25-- ) in right eye (OD) and - 9.50 - 2.50 × 60 (20/70-- ) in left eye (OS). A topography-guided transepithelial-photorefractive keratectomy (ttPRK) was performed to correct high-order aberrations on OS, resulting in corneal surface and coma improvement, and CDVA achieved 20/30. Correction of residual ametropia was performed with an iris-fixated toric phakic lens in OU. CDVA improved to 20/20- (Plano) in OD and 20/20- (Plano - 1.00 90°) in OS. In conclusion, it is possible to rehabilitate a patient with keratoconus and high ametropia after intrastromal corneal ring segments (ICRS) implantation associating ttPRK and phakic lens (”Trioptics”).     

Evaluation of intrastromal corneal ring segments for treatment of keratoconus with a mechanical implantation technique

Purpose:

To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation in patients with keratoconus using a mechanical implantation technique.

Materials and Methods:

Thirty eyes of 17 patients with keratoconus were enrolled. ICRSs (Keraring) were implanted after dissection of the tunnel using Tunc''s specially designed dissector under suction. A complete ophthalmic examination was performed, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent, keratometric readings, inferosuperior asymmetry index (ISAI), and ultrasound pachymetry. All 3-, 6-, and 12-month follow-ups were completed, and statistical analysis was performed.

Results:

The mean preoperative UDVA for all eyes was 1.36 ± 0.64 logMAR. At 12 months, the mean UDVA was 0.51 ± 0.28 logMAR (P = 0.001), and the mean preoperative CDVA was 0.57 ± 0.29 logMAR, which improved to 0.23 ± 0.18 (P = 0.001) at 1 year. There was a significant reduction in spherical equivalent refractive error from –6.42 ± 4.69 diopters (D) preoperatively to –1.26 ± 1.45 D (P = 0.001) at 1 year. In the same period, the mean K-readings improved from 49.38 ± 3.72 D to 44.43 ± 3.13 D (P = 0.001), and the mean ISAI improved from 7.92 ± 3.12 to 4.21 ± 1.96 (P = 0.003). No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during and or after surgery.

Conclusion:

ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for keratoconus. All parameters improved by the 1-year follow-up.     

Long-term follow up of intracorneal ring segment implantation in 932 keratoconus eyes

PurposeTo evaluate the progression of keratoconus in 932 eyes of 659 patients through visual, refractive and topographic data after intracorneal ring segment (ICRS) implantation.MethodsRetrospective review of 659 patients who underwent ICRS (Intacs®) implantation for keratoconus between September 1997 and November 2017. Demographics, preoperative and postoperative uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) in LogMAR, corneal topography parameters (thinnest pachymetry, Kmax), central corneal pachymetry and total follow-up time were evaluated. Statistical analysis was performed using IBM SPSS Statistics 24.0 for windows.ResultsNine hundred and thirty-two eyes of 659 patients, with a mean age of 30.41 years (range 11–76 years), were evaluated. Mean total follow up time was 3.02 years. Forty-one eyes had a total follow up of over 10 years. Both UCVA and BCVA improved significantly after ICRS implantation (P < 0.01). Only 18 eyes (2.66% of eyes of patients under 35 years of age) were found to have progression of keratoconus based on postoperative topographic data (Mean age 23.00 years, 55.6% female, total follow-up 2 to 10 years)ConclusionICRS implantation showed long-term improvement and stability in visual and topographic results in a large case series of patients with keratoconus. Only a minimal rate of progression was detected in young patients. However, further prospective studies need to be conducted to better define predictability of postoperative visual outcomes and progression.     

Intrastromal corneal ring segments for management of keratoconus

Keratoconus is a progressive corneal ectasia, which can be managed both by conservative measures like glasses or contact lenses in non-progressive cases or surgical procedures like collagen crosslinking (CXL) with or without adjuvant measures like intrastromal corneal rings segments (ICRS) or topography guided ablation. Various kinds of ICRS are available to the surgeon, but it is most essential to be able to plan the implantation of the ring to optimize outcomes.

Aims:

The aim of this study is to evaluate the visual outcome and progression in patients of keratoconus implanted with ICRS.

Materials and Methods:

Two different types of ICRS-Intacs (Addition Technology) and Kerarings (Mediphacos Inc.) were implanted in 2 different cohorts of patients and were followed-up to evaluate the outcome of the procedure. All patients underwent a complete ocular examination including best spectacle corrected visual acuity, slit lamp examination fundus examination, corneal topography and pachymetry. The ICRS implantation is done with CXL to stop the progression of the disease. Improvement in uncorrected visual acuity (UCVA), best spectacle corrected visual acuity and topographic changes were analyzed.

Results:

A significant improvement in keratometry and vision was seen in both groups.

Conclusion:

ICRS have been found to reduce corneal irregularity and flatten keratometry with improvement in UCVA and best corrected visual acuity.     

Intrastromal corneal ring segments and corneal anterior stromal necrosis

Poly(methyl methacrylate) refractive intracorneal ring segments (ICRS) can be removed for a refractive miscorrection or for early complications after implantation. We report the first case of a woman who experienced anterior stromal necrosis 5 years after an ICRS surgical procedure.     

Intrastromal corneal ring implantation for the correction of myopia: 12-month follow-up

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.