Analysis of results related to good and bad outcomes of Intacs implantation for keratoconus correction

PURPOSE: To evaluate factors influencing good and poor outcomes after intracorneal ring segment implantation to correct keratoconus. SETTING: Instituto Oftalmológico de Alicante (Vissum Corporation), University of Miguel Hernandez, Alicante, Spain. METHODS: A retrospective comparative study of the visual outcome, 25 eyes of 21 patients were implanted after intracorneal ring segments (Intacs, Addition Technology) as a method to correct keratoconus. Outcomes were evaluated 6 months after implantation based on the visual results. Group A comprised 20 eyes that gained 3 lines or more of best spectacle-corrected visual acuity (BSCVA) to correct keratoconus, and Group B comprised 5 eyes that lost 1 line of BSCVA. RESULTS: In Group A, the preoperative mean BSCVA was 0.43 (20/50) and the postoperative mean BSCVA, 0.82 (20/20) (P< or =.0001). In Group B, the preoperative mean BSCVA was 0.36 (20/63) and the postoperative mean BSCVA, 0.24 (20/80) (P< or =.02). The preoperative mean sphere power was 3.90 diopters (D) greater in Group B than in Group A (P< or =.007); the mean spherical equivalent was 4.36 D greater (P< or =.007), and the mean K-reading was 6.91 D greater (P< or =.001). The postoperative reduction in spherical dioptric power was 2.11 D (P< or =.027) and the mean spherical equivalent, 2.81 D (P< or =.003), significant only in Group A. The reduction in mean central K-readings was 4.30 D (P< or =.0001) in Group A and 6.19 D (P< or =.014) in Group B. The correlation of the preoperative mean K value to the postoperative BSCVA was significant at the .01 level by the Pearson test (-0.67). In Group A, all eyes (100%) had a mean K-reading < or =53 D. In Group B, 4 eyes (80%) had a mean K-reading > or =55 D. CONCLUSION: Intacs provided better results in visual acuity and corneal topography quality and significantly reduced the spherical equivalent in eyes with keratoconus with relatively low mean K values (< or =53 D) and a relatively low spherical equivalent. In advanced keratoconus (mean K-reading > or =55 D), poor results can be anticipated.     

Treating keratoconus with intacs corneal ring segments

PURPOSE: To assess the safety and efficacy of Intacs inserts for the treatment of mild to moderate keratoconus. METHODS: In a nonrandomized prospective clinical trial, 50 eyes of 37 patients with mild to moderate keratoconus were implanted with asymmetrical pairs of Intacs segments. Patients were interviewed and observed preoperatively and 24 hours, 1 week, 1, 3, 6, and 12 months postoperatively. Main outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, satisfaction with vision and trouble with vision, Visual Function-7 score, and surgically induced change in corneal astigmatism. RESULTS: Of the 50 operations performed, 92% were successful. Mean follow-up was 6.3 +/- 3.2 months. In 4 (8%) eyes, both Intacs segments were removed. In addition, 7 refractive adjustments in 7 eyes were performed successfully to improve visual and surgical outcome. Both BSCVA and UCVA improved throughout follow-up. Visual functioning index improved from 61.6 +/- 21.1 to 80.8 +/- 22.5, and the percentage of satisfaction with vision improved from 24.3% to 87.5% at 12 months. Vector analysis of astigmatism correction showed that the mean change in corneal astigmatism was 2.9 +/- 2.9 D at 6 months postoperatively. By selecting patients in whom astigmatism correction was best (index of success >0.5), an analysis was performed to determine individual factors important in successful surgery. Preoperatively these 11 (22%) eyes did not differ significantly from the remaining eyes and the only significant value was low K readings in the flat axis. CONCLUSIONS: Asymmetric Intacs placement improves BSCVA and UCVA and reduces astigmatism in patients with mild to moderate keratoconus. The procedure of Intacs placement is safe and effective. The change in astigmatism correction is unpredictable.     

European clinical evaluation: use of Intacs for the treatment of keratoconus

PURPOSE: To evaluate the safety and efficacy of Intacs inserts in keratoconic eyes to alter corneal shape and refractive power and stabilize the progression of corneal ectasia. SETTING: Service d'Ophtalmologie, Bordeaux, France. METHODS: In this prospective study, 57 eyes with clear central corneas that were diagnosed with keratoconus and contact lens intolerant were followed for up to 1 year. The primary objectives were to assess the safety of Intacs and the visual outcomes by measuring uncorrected visual acuity (UCVA), best corrected visual acuity, manifest refraction spherical equivalent, keratometry, intraocular pressure (IOP), pachymetry, and patient satisfaction. The stability of the refraction, keratometry, and visual acuity measurements was also assessed. RESULTS: At the 6-month examination, 78% of patients showed improvement of 2 lines or more in UCVA (P<.001). Best corrected visual acuity of 20/40 or better improved from 53% of patients preoperatively to 74% of patients (P< or =.033). Manifest refraction spherical equivalent improved to 3.1 +/- 2.5 diopters (D) (P<.001) compared with the preoperative examination. Keratometry decreased a mean of -4.3 +/- 2.8 D from the preoperative readings (P< or =.002). These changes appeared to be stable over time. At 6 months, there were no adverse events, no clinically significant increase in IOP, and no decrease in central corneal thickness. In 7 of 57 eyes (12%), the Intacs were removed due to dissatisfaction with visual symptoms. There were no adverse effects or complications associated with the Intacs removal. CONCLUSIONS: Intacs were safe and effective for treating keratoconus. All patients demonstrated improved objective visual outcomes; functional vision was restored in most patients. Intacs were removed without permanent sequelae.     

Intracorneal ring segments for keratoconus correction: long-term follow-up

PURPOSE: To evaluate long-term results and stability of intracorneal ring segment (Intacs) implantation for keratoconus correction. SETTING: Vissum, Instituto Oftalmológico de Alicante and University of Miguel Hernandez, Alicante, Spain. METHODS: This retrospective study comprised 13 eyes operated on between April 2000 and December 2001 that had Intacs implantation for keratoconus correction. The outcomes were evaluated at 6, 12, 24, and 36 months in all eyes and at 48 months (6 eyes). RESULTS: Mean best spectacle-corrected visual acuity (BSCVA) increased from 0.46 (20/50) preoperatively to 0.66 (20/30) postoperatively (P< or =.001). Mean decrease of inferior-superior (I-S) asymmetry was 2.81 diopters (D) (P< or =.02), and the average K-value was 3.13 D (P< or =.001). Mean difference between 6 and 36 months (stability) showed no significant difference regarding BSCVA (P< or =.5) and I-S asymmetry (P< or =.6). Although a significant increase was noticed in the average K by 1.67 D (P< or =.002), at 36 months it did not reach the initial preoperative values. CONCLUSION: Intacs increased the BSCVA and decreased I-S asymmetry with stability up to 36 months. In spite of the decrease of the K-values at 6 months, a further significant increase was detected 36 months after surgery.     

Long-term outcomes of photorefractive keratectomy in eyes with previous epikeratophakia for keratoconus

PURPOSE: To determine the long-term safety and effectiveness of photorefractive keratectomy (PRK) in the treatment of refractive errors after epikeratophakia (EP) for keratoconus. METHODS: Ten patients (14 eyes) who had refractive errors after EP for keratoconus received PRK surgery. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refractive error, corneal astigmatism, pachymetry, corneal topography, and complications were monitored. RESULTS: Mean follow-up after PRK was 63.4 +/- 19.8 months. Mean spherical equivalent was -5.5 +/- 3.9 D before PRK, -0.9 +/- 0.5 D at 1 month after PRK, and -1.5 +/- 1.0 D at 3 years. Mean astigmatism was 4.2 +/- 2.1 D before PRK, 1.2 +/- 0.5 D at 1 month after PRK, and 1.5 +/- 0.6 D at 3 years. Thirteen (93%) eyes had an UCVA <20/40, and 12 (86%) had a BSCVA of 20/40 or better before PRK. At 1 year, the UCVA was 20/40 or better in 8 (57%) eyes, and the BSCVA was 20/40 or better in all eyes. Mean central corneal thickness was 749 +/- 35 microm before PRK and 621 +/- 56 mum at 3 years. During the follow-up period, haze (grade no more than 1.0) was observed in 2 eyes. No immune rejection episode or recurrent keratoconus was found. CONCLUSIONS: PRK appears to be reliable and safe for the correction of residual ametropia after EP for keratoconus, and the visual acuity can remain stable after PRK for a long time.     

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.     

Effect of age on outcomes in patients with keratoconus treated by Intacs using a femtosecond laser

PURPOSE: To compare the response to Intacs treatment in different age groups of patients with keratoconus. METHODS: One hundred nine eyes with keratoconus treated with Intacs by using femtosecond laser were divided into three groups according to age: group 1, 13 to 19 years old (n = 20); group 2, 20 to 35 years old (n = 75), and group 3, 35 to 56 years old (n = 14). All patients had clear central corneas and were contact lens intolerant. Pre- and postoperative examination data including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), mean refraction spherical equivalent (MRSE), and K-readings were evaluated. Pre- and postoperative corneal topographies were examined. Visual acuities were detected by Snellen chart. Postoperative follow-up was 1 year. RESULTS: The improvement in UCVA, BSCVA, MRSE, and K-readings postoperatively in each group was statistically significant. The pre- and postoperative differences in UCVA (P = .930), BSCVA (P = .470), MRSE (P = .205), and K-readings (P = .545) were similar among groups. CONCLUSIONS: Intacs treatment is safe and effective in all age groups. Therefore, it may be an alternative treatment to penetrating keratoplasty in adolescent patients with keratoconus who are intolerant of contact lenses.     

Comparison of single-segment and double-segment Intacs for keratoconus and post-LASIK ectasia

PURPOSE: To evaluate the efficacy of single-segment Intacs and compare with double-segment Intacs in subjects with post-LASIK ectasia and keratoconus. DESIGN: Retrospective comparative analysis. METHODS: setting: Boxer Wachler Vision Institute, Beverly Hills, California, USA. study population: Thirty-seven eyes of 28 patients with keratoconus and post-LASIK ectasia classified into two groups: single-segment group (17 eyes, 11 patients) and double-segment group (20 eyes, 17 patients). Both groups were matched for age, visual acuity (uncorrected, UCVA; best spectacle-corrected, BSCVA), refractive error (sphere, cylinder, spherical equivalent), and keratometry (K) value (flat, steep, average) by t test for equality of means. intervention: Single- or double-segment Intacs procedure with axis of incision for insertion in the steep axis of manifest refraction. main outcome measure: Improvement of acuity, refractive error, K values, and inferior-superior (I-S) ratio. RESULTS: There was more improvement in UCVA in the single-segment group (nine lines) than the double-segment group (2.5 lines), P < .01; in BSCVA in the single-segment group (2.5 lines) than the double-segment group (<1 line), P < .01; in steep K values in the single-segment group (2.76 diopters +/- 2.68) than the double-segment group (0.93 diopters +/- 2.01), P = .02; and in I-S ratio in the single-segment group (9.51 +/- 7.49) than the double-segment group (4.22 +/- 4.82), P = .01; and greater cylinder decrease after Holladay vector analysis in the single-segment group (5.69 diopters +/- 3.10) than the double-segment group (1.58 diopters +/- 3.09), P < .01. CONCLUSIONS: Single-segment Intacs improved both UCVA and BSCVA by differential flattening of inferior meridian and steepening of superior meridian as reflected by change in I-S ratio.     

Intracorneal ring segment implantation for the management of keratoconus: safety and efficacy

PURPOSE: To assess the safety and efficacy of intracorneal ring segment (Intacs, Addition Technology, Inc.) implantation in the management of keratoconus. SETTING: Department of Ophthalmology and Ophthalmic Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran. METHODS: This prospective case series comprised 30 keratoconic eyes (22 patients) with a clear central cornea that had Intacs implantation. All patients were contact-lens intolerant. The main outcome measures were uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, keratometry, and pachymetry. Patients were examined before Intacs implantation as well as 1 week and 1, 3, and 6 months postoperatively. RESULTS: The mean age of the 5 women and 17 men was 25.9 years +/- 5.29 (SD). The mean UCVA improved from 0.60 +/- 0.311 logMAR preoperatively to 0.29 +/- 0.20 logMAR 6 months postoperatively (P<.001) and the mean BSCVA, from 0.25 +/- 0.16 logMAR to 0.13 +/- 0.14 logMAR, respectively (P<.001).The mean spherical equivalent improved from -6.93 +/- 3.52 diopters (D) preoperatively to -3.23 +/- 2.81 D at 6 months and the mean refractive cylinder, from -4.65 +/- 1.85 D to -3.90 +/- 1.70 D, respectively. The mean keratometry decreased from 49.84 +/- 3.58 D preoperatively to 47.90 +/- 3.58 D postoperatively (P<.001). Three eyes had ring exposure, and 1 eye had bacterial keratitis and ring exposure. CONCLUSION: Intacs implantation appeared to be effective in improving UCVA and BSCVA in patients with mild to moderate keratoconus and contact-lens intolerance.     

Intracorneal rings to correct corneal ectasia after laser in situ keratomileusis

PURPOSE: To evaluate the potential of using intrastromal corneal ring technology (Intacs, KeraVision) to correct posterior ectasia after laser in situ keratomileusis (LASIK) for myopia. SETTING: Department of Cornea and Refractive Surgery, Instituto Oftalmológico de Alicante, and Miguel Hernández University School of Medicine, Alicante, Spain. METHODS: In this prospective noncomparative intervention case series, Intacs segments were implanted in 3 eyes that developed posterior ectasia after myopic LASIK with clear central corneas. Posterior ectasia and corneal thickness were tested using the Orbscan II Slit Scanning Corneal Topography/Pachymetry System (Orbtek Inc.). Segment thickness varied based on corneal topography analysis and refraction. The mean follow-up was 8.3 months (range 7 to 11 months). RESULTS: The cases showed marked improvement after Intacs segment implantation. Postoperatively, there was a reduction in the magnitude of the posterior and anterior corneal surface steepening or ectasia and an increase in the topographical regularity index. In addition, the significantly enlarged optical zones resulted in a favorable visual outcome. In 2 eyes, the uncorrected visual acuity (UCVA) was 20/40 postoperatively. In the third eye, there was a residual refractive error; the UCVA was 20/50 and the best spectacle-corrected visual acuity, 20/40. CONCLUSIONS:Intacs intrastromal corneal rings used as a mechanical device may alter the biomechanical properties of the cornea for the correction of iatrogenic keratectasia and the associated residual myopia.     

Clinical outcomes after deep anterior lamellar keratoplasty using the big-bubble technique in patients with keratoconus

PURPOSE: To report clinical outcomes of deep anterior lamellar keratoplasty (DALK) using the big-bubble technique in patients with keratoconus. DESIGN: Prospective noncomparative interventional study. METHODS: Setting: Single hospital. Patients: Eighty-one unselected consecutive patients with moderate to advanced keratoconus intolerant to contact lenses and with poor spectacle-corrected visual acuity. Intervention: DALK big-bubble technique. Main Outcome Measures: Intraoperative and postoperative complications, postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, corneal topography, and endothelial cell density. RESULTS: Seventy-eight procedures (96%) were completed as DALK. Big-bubble was achieved in 50 cases (64%); 28 (36%) required manual intrastromal dissection. Intraoperative microperforations occurred in 11 cases (13%). Baseline mean uncorrected visual acuity was 20/500 and 20/60 two years after surgery. Average preoperative BSCVA, was 20/100 and 20/30 at the end of follow-up. Final BSCVA was better in patients in whom big-bubble with exposure of the Descemet membrane was achieved (P < .05). Average keratometry and SD (standard deviation) refraction changed from 62.1 +/- 6.7 diopters and -10.76 +/- 5 diopters to 47.51 +/- 4.73 diopters and -1.81 +/- 3.2 diopters, respectively after surgery. Mean preoperative endothelial cell density was 2202.29 +/- 392.35 cells/mm(2) and 2034 +/- 438.39 cells/mm(2) two years after surgery. Two patients developed stromal rejection. CONCLUSIONS: The DALK big-bubble technique is a valuable treatment in patients with keratoconus. Visual outcome is comparable to standard penetrating keratoplasty (PK) when formation of big-bubble with exposure of the Descemet membrane (DM) was achieved. Clinically important graft-host interface developed in some cases after manual intrastromal dissection. Stromal rejection is a rare complication.     

Intacs for keratoconus and post-LASIK ectasia: mechanical versus femtosecond laser-assisted channel creation

PURPOSE: To evaluate the efficacy of intracorneal ring segments to treat keratoconus and post-laser in situ keratomileusis (LASIK) keratectasia implanted by using either mechanical dissection or a femtosecond laser. METHODS: Thirty-three eyes of 29 patients had intracorneal ring segments implanted by using mechanical dissection (17 eyes) or a femtosecond laser (16 eyes). Mean follow-up was 10.3 months. Parameters assessed before and after surgery included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent (MRSE), refractive cylinder (RC), best contact lens-corrected visual acuity (BCLVA), and contact lens tolerance. RESULTS: Statistically significant changes occurred for all parameters when we analyzed all 33 eyes as 1 group. Mean UCVA LogMar values improved from 1.0 +/- 0.3 (20/200) to 0.6 +/- 0.4 (20/80) (P < 0.0005). Mean BSCVA changed from 0.3 +/- 0.2 (20/40) to 0.2 +/- 0.2 (20/30) (10%; P < 0.05), and MRSE from -9 +/- 4 to -7 +/- 4 D (P < 0.05; 20%). There was a decrease of 0.5 D or more of RC in 62% of eyes. BCLVA improved from 0.2 +/- 0.2 (20/30) to 0.1 +/- 0.1 (20/25) after surgery (P < 0.02). Contact lens tolerance improved in 81% of eyes. There was no statistically significant difference in outcomes between mechanical dissection and femtosecond laser-assisted techniques. However, although statistical power was adequate to detect changes in clinical parameters as a result of surgery, it was not sufficient to conclusively show such differences between surgical techniques. CONCLUSIONS: For mild to moderate cases of keratoconus and post-LASIK keratectasia, the use of a femtosecond laser for Intacs channel creation seems as effective as mechanical dissection. Future studies are warranted to further evaluate channel creation by a femtosecond laser.     

Intacs implantation using a femtosecond laser for management of keratoconus: Comparison of 306 cases in different stages

PURPOSE: To evaluate the efficacy of intrastromal ring segment (Intacs, Addition Technology, Inc.) implantation and analyze outcomes according to different keratoconus stages. SETTING: Kudret Eye Hospital, Ankara, Turkey. METHOD: In this retrospective noncomparative case series, 306 keratoconic eyes of 255 patients who had Intacs segment implantation were reviewed. Patients were grouped according to the Amsler-Krumeich keratoconus classification (stage II, 155 eyes; stage III, 83 eyes; stage IV, 68 eyes). The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), central corneal curvature, spherical and cylindrical manifest refractions, and central corneal thickness were analyzed and compared according to keratoconus stage. RESULTS: At a mean follow-up of 10.39 months +/- 5.04 (SD), the BCVA improved in 71.6% of eyes and the UCVA improved in 75.7% of eyes. The mean keratometry (K) decreased from 50.7 diopters (D) to 47.9 D (P<.05); the mean manifest spherical refraction, from -6.04 D to -3.09 D (P<.05); and the mean manifest cylindrical refraction, from -4.11 D to -3.82 D (P>.05). The changes in BCVA and manifest spherical and cylindrical refractions were not statistically different between the different keratoconus stages (P >.05). There was less change in UCVA and more improvement in the mean K value after Intacs treatment in stage IV than in the other stages (P<.05, analysis of variance). CONCLUSIONS: Intacs treatment with a femtosecond laser was effective for management of keratoconus of all stages. Improvement in UCVA may be less in severe keratoconus than in moderate keratoconus.     

Intacs for the correction of keratoconus: two-year follow-up

PURPOSE: To evaluate the long-term safety and efficacy of Intacs segments (Addition Technology, Inc.) for the treatment of keratoconus in terms of intraoperative and postoperative complications, visual outcome, restoration of contact lens tolerance, and inhibition of disease progression. SETTING: Service d'Ophtalmologie, CHU Pellegrin, Bordeaux, France. METHODS: This prospective, 2-year follow-up study comprised 100 keratoconic eyes with clear central corneas and contact lens intolerance. The best spectacle-corrected visual acuity (BSCVA), uncorrected visual acuity (UCVA), refractive error, keratometry, pachymetry, and slitlamp examination were assessed preoperatively and 1 and 2 years after Intacs implantation. RESULTS: At 2 years, the UCVA and BCVA improved in 80.5% and 68.3% of eyes, respectively (P<.001). The proportion of eyes with a BCVA >or=0.5 (20/40) increased from 22.0% at baseline to 51.2% and 53.7% at 1 year and 2 years, respectively (P<.001). The manifest refraction spherical equivalent improved from a mean of -6.93 diopters (D) +/- 3.91 (SD) preoperatively to -4.01 +/- 3.16 D at 1 year and -3.80 +/- 2.73 D at 2 years (P<.001). The mean keratometry readings decreased from 50.1 +/- 5.6 D preoperatively to 46.4 +/- 5.3 D at 1 year and 46.8 +/- 4.9 D at 2 years (P<.001). Contact lens tolerance was restored in over 80% of cases. Postoperative slitlamp observations revealed no clinically significant issues. The segments were removed from 4 eyes without complications or sequelae. CONCLUSION: Intacs implantation was a safe and efficacious treatment for keratoconus. Significant and sustained improvements in objective visual outcomes were achieved in most cases, with restoration of contact lens tolerance.     

Long-term follow-up of Intacs from a single center

PURPOSE: To evaluate the long-term visual results in patients having Intacs placement for the correction of mild myopia. SETTING: Department of Ophthalmology, Mount Sinai School of Medicine and the Mount Sinai Hospital of Mount Sinai NYU Health, New York, New York, USA. METHODS: Patients with mild myopia (spherical equivalent between -0.75 and -4.50 diopters [D]) were enrolled to have Intacs placement between May 1995 and March 1999 under United States Food and Drug Administration Phase II and Phase III clinical trials for intrastromal corneal ring segments (ICRS). Six insert thicknesses were evaluated: 0.21, 0.25, 0.30, 0.35, 0.40, and 0.45 mm. The long-term results evaluated were uncorrected visual acuity (UCVA), maintenance of best spectacle-corrected visual acuity (BSCVA), predictability and stability of the refractive effect, induced manifest refraction cylinder, slitlamp findings, self-reported visual symptoms, and maintenance of mesopic contrast sensitivity. RESULTS: One hundred fourteen eyes of 73 patients were enrolled; 113 eyes of 72 patients received Intacs. There were no serious intraoperative or postoperative complications. The mean follow-up was 17.5 months +/- 8.9 (SD). At the end of this period (number of eyes evaluated = 100), the UCVA was 20/40 or better in 95 eyes (95.0%), 20/20 or better in 72 (72%), and 20/16 or better in 41 (41%). None of the 113 eyes lost 10 or more letters or 2 or more lines of preoperative BSCVA. The mean change in the cycloplegic refraction spherical equivalent for the 6 insert thicknesses was as follows: -0.75 +/- 0.00 D for 0.21 mm; -1.17 +/- 0.42 D for 0.25 mm; -2.00 +/- 0.54 D for 0.30 mm; -2.59 +/- 0.53 D for 0.35 mm; -3.09 +/- 0.54 D for 0.40 mm; and -3.82+/-0.80 D for 0.45 mm. The refractive correction was within +/-1.0 D of the predicted outcome in 103 eyes (92.0%) and within +/-0.5 D in 72 eyes (63.7%). Intacs were removed from 6 eyes (5.3%). All 4 eyes for which data were available 3 months after removal returned to within +/-0.5 D of their preoperative manifest refraction spherical equivalent. Intacs were exchanged because of undercorrection in 2 eyes (1.8%). These eyes gained 3 and 5 lines of UCVA 12 months and 18 months, respectively, after the exchange procedure. Overall, 85.7% (36/42) of the patients were satisfied with the results of the Intacs procedure. CONCLUSION: Intacs safely and effectively corrected mild myopia. Placement is a brief, easy outpatient procedure. The refractive effect was predictable and stable over long-term follow-up. Results from a limited number of removal and exchange procedures indicate that Intacs are removable and adjustable.     

Intracorneal asymmetrical rings for keratoconus: where should the thicker segment be implanted?

PURPOSE: To report a 20-year-old man who presented with monocular diplopia in the right eye with uncorrected visual acuity (UCVA) of 0.3 and best spectacle-corrected visual acuity (BSCVA) of 1.0 with -0.50 -3.00 x 45 degrees. METHODS: Clinical examination and corneal topography revealed grade I keratoconus in the right eye. Intracorneal ring segments (INTACS; Addition Technology, Des Plaines, III) were implanted in May 2004 without surgical complications at 415 microm (70% of the corneal thickness), with the 450-microm segment implanted superiorly and the 250-microm segment inferiorly. RESULTS: For 2 months postoperatively, BSCVA remained at 0.4 with +1.50 -4.50 x 25 degrees. The segments were reversed, implanting the 450-microm (thick) segment inferiorly and the 250-microm (thin) segment superiorly. One week later, UCVA was 1.0 and remained stable for 3 months after reimplantation. CONCLUSIONS: This report shows that implanting the thicker segment inferiorly provides better visual results.     

Ferrara intracorneal ring segments for keratoconus

PURPOSE: To assess the outcome of Ferrara intracorneal ring segments for keratoconus. SETTING: Private practice and university hospital, Porto Alegre, Brazil. METHODS: In this retrospective noncomparative interventional case series, 51 keratoconus eyes of 47 patients that had Ferrara intracorneal ring segment implantation were reviewed. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), central corneal curvature, corneal astigmatism, surface regularity index, surface asymmetry index, and complications were analyzed. RESULTS: At a mean follow-up of 13.0 months +/- 8.7 (SD), the BSCVA improved in 86.4% of eyes, was unchanged in 1.9%, and worsened in 11.7%. The UCVA improved in 86.4% of eyes, was unchanged in 7.8%, and worsened in 5.8%. The mean spherical equivalent (SE) was reduced from -6.08 +/- 5.01 diopters (D) to -4.55 +/- 5.71 D and the mean refractive astigmatism, from -3.82 +/- 2.13 D to -2.16 +/- 2.07 D. The mean central corneal curvature was reduced from 48.76 +/- 3.97 D to 43.17 +/- 4.79 D. Eyes with central keratoconus had statistically significantly better results than eyes with inferior keratoconus in topographic astigmatism, SE, and refraction cylinder. Penetrating keratoplasty was avoided in 38 eyes (74.5%) during the follow-up. Intracorneal ring segment decentration occurred in 2 eyes (3.9%), segment extrusion in 10 eyes (19.6%), bacterial keratitis in 1 eye (1.9%) with segment extrusion, and a disciform keratitis in 1 eye (1.9%). CONCLUSION: Implantation of Ferrara intracorneal ring segments in patients with keratoconus was a safe and reversible procedure that led to stable results and avoided or delayed PKP in many cases.     

Delayed ectasia following LASIK with no risk factors: is a 300-microm stromal bed enough?

PURPOSE: To report a case of ectasia occurring > 4 years following LASIK with no risk factors and a residual stromal bed > 300 microm. METHODS: A 33-year-old woman presented 4 years after LASIK with mild blurring in the left eye. Uncorrected visual acuity (UCVA) had been 20/20 in both eyes previously. RESULTS: Uncorrected visual acuity was 20/20 and 20/40 in the right and left eyes, respectively. Best spectacle-corrected visual acuity (BSCVA) was 20/20 with -0.75 +2.25 x 70 degrees refraction in the left eye, which matched topography. Preoperative corneal thickness was 595 microm, and topography showed no risk factors preoperatively or immediately postoperatively. Calculated residual stromal bed was 342 microm and measured 400 microm with ultrasound microscopy. One year postoperatively, UCVA decreased to 20/400, and BSCVA decreased to 20/60 with refraction of -4.50 +5.00 x 90 degrees. The patient was intolerant of contact lens wear and is considering collagen cross-linking, Intacs, or corneal transplantation. CONCLUSIONS: Ectasia can occur more than 4 years after LASIK. Its etiology is unknown and management is challenging.