Ferrara Intrastromal Corneal Ring Segments Research Articles

Two-stage treatment of ametropia in patients with keratoconus and cataracts

Keratoconus (KC) is a progressive degenerative corneal disease, leads to the aberration of biomechanical and optical properties and thinning of the cornea, causes astigmatism and decreases visual acuity.Materials and methods. 33 patients (35 eyes) with stages II–III of non-progressive keratoconus and concomitant cataracts of various stages of maturity were operated on. The average age of the patients was 46.5 ± 2.7 (41–63) years old. The operations were performed according to our proposed two-stage method of treating ametropia in patients with KC and cataracts (Patent of the Russian Federation No. 2748634 of 28.05.2021). The first stage was the implantation of FERRARA intrastromal corneal ring segments (ICRS) with thickness from 150 to 350 μm. To correct residual refractive error in 5–7 months after stage 1, patients underwent stage 2: cloudy lens was removed and replaced with toric posterior chamber intraocular lens (TIOL) – AcrySof IQ Toric (Alcon, USA), T-fl ex Toric RayOne (Rayner, UK).Results and discussion. After stage 1 of the operation (ICRS implantation), the uncorrected visual acuity (NCVA) was 0.2 ± 0.03, the best corrected visual acuity (BCVA) was 0.4 ± 0.02. In 1 month after stage 2 (phacoemulsifi cation + TIOL) NCVA was 0.64 ± 0.11 and BCVA was 0.74 ± 0.12. During the entire follow-up period after the surgery visual functions, refraction, and rotational stability of TIOL were stable.Conclusions. Conducting a two-stage surgical intervention in patients with keratoconus and cataracts allows to stop the progression of the disease and effectively correct the ametropia concomitant with keratoconus.

Ferrara Rings for Visual Rehabilitation in Eyes with Keratoconus and Previous Cross-Linking Using the Ferrara Ring Nomogram.

Purpose: To report the visual, refractive and tomographic outcomes following the implantation of intrastromal corneal ring segments (ICRS) (Ferrara rings, AJL Ophthalmics, Miñano, Spain) in eyes with a history of keratoconus and corneal cross-linking using the Ferrara ring nomogram. Methods: Retrospective, interventional case series performed at the Corneoplastics Unit, Queen Victoria Hospital, East Grinstead, United Kingdom. Results: 21 eyes of 19 patients with a history of keratoconus and prior corneal collagen cross-linking had Ferrara Intrastromal Corneal Ring Segments implanted between December 2015 and October 2017. The number, thickness and length of ring segments was chosen based on the Ferrara ring company nomogram. Mean uncorrected visual acuity (UDVA) improved from 0.88 to 0.52 logMAR (p < 0.001). Mean corrected visual acuity (CDVA) improved from 0.47 to 0.36 logMAR (p = 0.046). The percentage of eyes achieving 20/40 UDVA and CDVA increased from 5% to 38% and from 38% to 67%, respectively. Of the eyes, 52.3% gained at least two lines of CDVA. The spherical equivalent improved from −7.51D to −3.76D (p < 0.001) and the refractive astigmatism magnitude improved from 5.14D to 2.76D (p = 0.004). There were significant improvements in the corneal tomography with mean keratometry (KM) improving from 50.40D (3.53) to 48.24D (3.00) (p = 0.01) and keratometric astigmatism magnitude improving from 5.14D (2.91) to 2.76D (1.67) (p = 0.004). Conclusion: Insertion of Ferrara rings in keratoconic eyes with a history of prior cross-linking using the company nomogram results in significant improvements in visual, refractive and tomographic outcomes.

Refractive and visual outcomes after Ferrara corneal ring segment implantation at a 60% depth in keratoconic eyes: case series

This report addresses refractive, topographic, visual acuity, and optical coherence tomography outcomes 12 months after femtosecond, laser-assisted insertion of Ferrara intrastromal corneal ring segments in keratoconic eyes at a depth of 60%. Interventional, prospective, non-comparative case series. We performed femtosecond, laser-assisted insertion of Ferrara intrastromal corneal ring segments in 15 keratoconic eyes. We included patients with documented keratoconus who voluntarily signed informed consents if they had best spectacle-corrected visual acuity ≥0.30 logMAR and corneal thickness ≥400 μm. We excluded patients with previous ocular surgery or corneal curvatures >65 diopters (D). Our main outcome measures were best spectacle-corrected visual acuity and corneal topographic parameters (flattest, steepest and average keratometry [K]), evaluated at baseline and at 1-,3-,6-, and 12-month follow-ups. The mean ± standard deviation baseline uncorrected visual acuity and best spectacle-corrected visual acuity were 1.03 ± 0.46 and 0.42 ± 0.13, respectively; the 12-month mean standard deviation uncorrected visual acuity and best spectacle-corrected visual acuity were 0.72 ± 0.37 and 0.31 ± 0.16, respectively, without significant differences (p=0.05 for both). The mean best spectacle-corrected visual acuity improvements were statistically significant after 3- (p=0.02) and after 6-months (p=0.02). The mean baseline flattest (K1), steepest (K2), and overall keratometries (mean power) were 48.35 ± 3.65 D, 53.67 ± 3.38 D, and 50.84 ± 3.36 D, respectively. The 12-month mean ± standard deviations for flattest-K1, steepest-K2, and overall K were 46.53 ± 3.70 D, 49.83 ± 3.50 D, and 48.12 ± 3.49 D respectively, with statistically significant differences for all three topographic parameters (p=0.01). Ferrara intrastromal corneal ring segment insertions at a depth of 60% yield satisfactory visual, refractive, and keratometric results in keratoconic eyes.

Clinical Outcomes After Implantation of 320°-Arc Length Intrastromal Corneal Ring Segments in Keratoconus.

To evaluate the clinical outcomes after implantation of a new 320°-arc length Ferrara intrastromal corneal ring segment (320-ICRS) in eyes of patients with keratoconus. A multicentric nonrandomized study was conducted in which a new 320-ICRS was placed in 138 eyes of 130 patients with keratoconus. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal volume, asphericity, lines of vision gain/loss, and vectorial analysis were assessed preoperatively and at the final follow-up visit after the procedure. The mean follow-up time was 6.2 ± 3.3 (SD) months (range 3-12 months). Mean UDVA improved from 20/250 to 20/60. Mean CDVA improved from 20/100 to 20/40. Mean Q improved from -1.12 ± 0.49 preoperatively to -0.28 ± 0.51 postoperatively (P < 0.001). Mean corneal volume increased from 56.2 ± 4.28 mm preoperatively to 57.6 ± 4.74 postoperatively (P < 0.001). Mean Km reduced from 53.3 ± 5.5 D preoperatively to 47.8 ± 4.6 D postoperatively (P < 0.001). The change in UDVA, CDVA, and topographic astigmatism was statistically significant (P < 0.0001). The 320-ICRS can efficiently and safely improve visual acuity in keratoconus, modifying the corneal shape to a more physiologic, aspheric shape.

Sequential intrastromal corneal ring segment and monofocal intraocular lens implantation for keratoconus and cataract: Long-term follow-up

To evaluate the efficacy, safety, predictability, and stability of sequential Ferrara intrastromal corneal ring segment (ICRS) and intraocular lens (IOL) implantation in patients with keratoconus and cataract. Fernández-Vega Ophthalmological Institute, Oviedo, Spain. Retrospective case series. This study comprised patients with keratoconus and cataract who had ICRS implantation followed 6months later by IOL implantation. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities and residual refractive errors, analyzed using vector analysis, were recorded preoperatively, 6months after ICRS implantation, 6months after IOL implantation, and 3years and 5years thereafter. Seventy eyes of 47 patients were studied. The mean UDVA was 1.08 logMAR ± 0.24 (SD) preoperatively, 0.95±0.31 logMAR 6months after ICRS implantation (P=.03), and 0.44±0.29 logMAR 6months after IOL implantation (P<.0001). The mean CDVA changed from 0.35±0.23 logMAR before surgery to 0.28±0.22 logMAR 6months after ICRS implantation (P<.0001) and to 0.11±0.16 logMAR 6months after IOL implantation (P<.0001). The UDVA and CDVA were stable over the period after the second procedure (P>.05). The spherical equivalent (SE) and the refractive cylinder declined steeply after IOL implantation (P<.001) and then were stable (P>.05). Sequential ICRS and IOL implantation provided good visual and refractive outcomes and was an effective, safe, predictable, and stable procedure for the treatment of patients with keratoconus and cataract.

Intrastromal Corneal Ring Segments in Children with Keratoconus

ABSTRACT Purpose To evaluate the long-term follow-up of Ferrara intrastromal corneal ring segments (ICRSs) (Ferrara Ophthalmics, Belo Horizonte, Brazil) implantation for the management of keratoconus in children. Study design Paulo Ferrara Eye Clinic, Belo Horizonte, Minas Gerais, Brazil. Materials and methods A total of 58 eyes of 37 children with keratoconus were included. One or two ring segments were inserted into the cornea, embracing the keratoconus area. Statistical analysis included preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), asphericity, pachymetry, and keratometry. Results Ferrara ICRS implantation significantly improved the mean UDVA and CDVA. Corneal tomography (Pentacam®) showed corneal flattening in all eyes implanted with the Ferrara ring. The mean K decreased, and the corneal asphericity and pachymetry increased in all cases. Conclusion The Ferrara ICRS improved all parameters after 2 years of implantation in children with keratoconus. There was significant corneal flattening after ring implantation with improvement of the UDVA and the CDVA. All studied parameters remained stable over time. How to cite this article Ferrara G, Ferrara P, Torquetti L. Intrastromal Corneal Ring Segments in Children with Keratoconus. Int J Kerat Ect Cor Dis 2017;6(2):45-48.

Ferrara Intrastromal Corneal Ring Segments

ABSTRACT The Ferrara intrastromal corneal ring segments (ICRS) are designed to treat ectatic corneal disorders, especially keratoconus. They have been used to reshape keratoconic corneas to improve uncorrected visual acuity, best-corrected visual acuity, contact lens tolerance and to delay or prevent the need for keratoplasty. Intrastromal corneal ring segments have several distinct and important advantages. The Ferrara ICRS have been used largely in several countries for the treatment of primary and secondary ectatic corneal disorders. This article reviews the latest data published and the clinical experience/findings on the treatment of keratoconus by the Ferrara ICRS implantation. How to cite this article Torquetti L, Sandes J, Ferrara G, Ferrara P. Ferrara Intrastromal Corneal Ring Segments. Int J Kerat Ect Cor Dis 2016;5(3):114-127.

Intrastromal Corneal Ring Segments Implantation in Patients with Mild Keratoconus

ABSTRACT Purpose The purpose of this study is to evaluate the topographic, topometric and visual changes after implantation of Ferrara intrastromal corneal ring segments (ICRS) in grades I and II keratoconus patients. Materials and methods The chart records of 50 consecutively operated keratoconus patients were reviewed. The patients were operated on by the same surgeon, with the manual technique. All patients were preoperatively and postoperatively evaluated with the Pentacam (OCULUS Optikgeräte, Wetzlar, Germany). The studied parameters were: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal asphericity and corneal volume. Results Fifty eyes of 42 patients (26 males and 16 females) were analyzed. The mean preoperative UDVA was 0.91 ranging from LogMAR 0.10 to 1.30. The mean postoperative CDVA was 0.19 ranging from 0.00 to 0.54 LogMAR. The postoperative CDVA was equal or better than 0.18 in 37 cases (74%). The mean K1 decreased from 45.80D (±2.52) preoperatively to 44.27D (± 2.10) postoperatively and the mean K2 value, from 49.06D (± 2.09) to 46.22D (±1.89). The mean asphericity increased from −0.71 preoperatively to −0.29 postoperatively. The average preoperative corneal volume was 56.89 ± 3.11 mm3 while the average postoperative corneal volume was 57.64 ± 3.05 mm3. Conclusion The study supports the early indication of implantation of Ferrara ICRS in mild to moderate keratoconus cases in order to achieve good visual, keratometric and ashpericity outcomes. How to cite this article Rodrigues PF, Ferrara G, Ferrara P, Dias WG, Torquetti L. Intrastromal Corneal Ring Segments Implantation in Patients with Mild Keratoconus. Int J Kerat Ect Cor Dis 2014;3(3):122-126.

Intrastromal corneal ring segments implantation in patients with keratoconus: 10-year follow-up.

To evaluate the long-term safety and efficacy of Ferrara intrastromal corneal ring segments (ICRS) (Ferrara Ring; AJL, Boecillo, Spain) in patients with keratoconus. The chart records of 36 eyes of 30 patients with keratoconus implanted with ICRS, operated on between July 1996 and January 2002, were retrospectively reviewed. The following parameters were studied: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry (K), and central corneal thickness. The outcomes were evaluated at 5 and 10 years after ICRS implantation. The mean UDVA (logMAR) improved from 1.01 ± 0.28 (20/200 Snellen) to 0.71 ± 0.38 (20/100 Snellen) at 5 years (P < .05) and 0.67 ± 0.25 (20/90 Snellen) at 10 years (P = .735). The mean CDVA (logMAR) improved from 0.45 ± 0.45 (20/55 Snellen) to 0.24 ± 0.19 (20/35 Snellen) at 5 years (P < .05) and 0.29 ± 0.09 (20/38 Snellen) at 10 years (P = .292). The mean maximum K value decreased from 54.99 ± 6.33 to 50.58 ± 5.11 D at 5 years (P < .05) and 50.65 ± 5.17 D at 10 years (P = .854). The mean minimum K value decreased from 48.85 ± 5.70 to 46.90 ± 5.08 D at 5 years (P < .05) and 47.12 ± 4.22 D at 10 years (P = .945). The central corneal thickness decreased from 457.42 ± 58.21 to 421.34 ± 74.12 μm at 5 years (P = .039) and 434.32 ± 77.65 μm at 10 years (P = .427). Intrastromal corneal ring segments can effectively improve UDVA and CDVA 10 years after implantation in patients with keratoconus.

Validation of an Experimental Animal Model for Corneal Additive Surgery

Purpose: To assess the hen cornea as a model for training and future wound healing studies after implantation of intrastromal corneal ring segments (ICRS) by clinical and optical outcomes. Setting: University of Valladolid, Valladolid, Spain. Design: Experimental study. Methods: One 90°, 150-μm thick polymethyl methacrylate Ferrara ICRS segment was manually implanted at 70-80% depth of 192 Gallus domesticus corneas. Clinical follow-up for 6 months included monitoring corneal thickness, epithelial wound closure, edema, haze, and the location and severity of deposits. The refractive state was also measured. After each animal was euthanized, corneas were processed for direct transmittance and histological analysis. Results: Complications were present in 16% of the eyes. Epithelial wound closure was completed at 3 ± 2 days. A slight corneal edema in the channel site was present for the first 15 days. All corneas had deposits by 4 months located along the inner, outer curvatures and under the segments. Corneal haze was present only at the incision site. ICRS induced hyperopic changes in the refractive state without changes in direct transmitance of central cornea. New cells and extracellular matrix were present around the segment where deposits were seen on clinical follow-up. Conclusions: With hen as an animal model, ICRS were implanted in a precise and reproducible way after a learning curve. Similar to humans, the follow-up period during the first 6 months after implantation showed fast wound closure, deposits, and haze at the incision site. ICRS in hens also reduced the refractive power without affecting the central cornea.

Clinical outcomes after intrastromal corneal ring segments reoperation in keratoconus patients.

To evaluate the clinical outcomes after Ferrara intrastromal corneal ring segments (ICRS) reoperation in patients with keratoconus. A total of 37 keratoconus eyes implanted with intrastromal corneal ring segments, which had an ICRS exchange, addition, reposition or removal were evaluated. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry (K), asphericity (Q) and pachymetry at the thinnest point (PTP) of the cornea were evaluated using a corneal tomography (Oculus Pentacam, USA). The mean follow-up time after the reoperation was 30.5±9.7 months. The mean UCVA improved from 20/300 to 20/80 (P=0.005); the mean BCVA improved from 20/160 to 20/50 (P=0.0002), the mean keratometry reduced from 49.33±4.19D to 46.16±3.90D (P=0.0001), the mean pachymetry at the thinnest point increased from 450±42.9μm to 469±40.8μm (P=0.0001). The asphericity increased from -0.84±0.74 to -0.35±0.81 (P=0.15) and the spherical equivalent reduced from -4.64±4.87D to -3.04±3.45D (P=0.137). The changes in the asphericity and spherical equivalent were not statistically significant. Ferrara ICRS implantation showed to be a reversible and readjustable surgical procedure for keratoconus treatment. Good outcomes can be obtained even after removal, addition, reposition or exchange of ICRS.

Spontaneous Corneal Rupture One Week after Intrastromal Ring Segment Surgery

ABSTRACT Purpose To report a case of spontaneous (nontraumatic) rupture of the cornea 7 days after intrastromal ring segment surgery in a patient with pellucid marginal degeneration (PMD). Methods Case report. Results A 37-year-old African woman complains blurred vision, photophobia, foreign body sensation and redness in her left eye 7 days after an uneventful implantation of a Ferrara intrastromal corneal ring segment (ICRS) for PMD. Left eye examination revealed the rupture in the thinnest point of the cornea between the limbus and the implanted lower ICRS, and the iris prolapsed through the wound. Conclusion To the best of our knowledge, this case is the first documented spontaneous rupture of the thinnest point of the cornea in a patient with PMD treated successfully with the ICRS procedure. We examined the causes of this early and dramatic evolution and emphasize the importance of a careful follow-up. How to cite this article Vaiano AS, De Benedetti G, Perno R, del Monte G, Valente C, Caramello G. Spontaneous Corneal Rupture One Week after Intrastromal Ring Segment Surgery. Int J Kerat Ect Cor Dis 2013;2(1):43-46.

The Influence of Corneal Volume in Surgical Planning: Insights for a New Parameter for the Ferrara Ring Nomogram

ABSTRACT Purpose To evaluate the corneal volume (CV) before and after Ferrara intrastromal corneal ring segments (ICRS) implantation and its influence in clinical outcomes in keratoconus patients. Materials and methods A total of 77 eyes of 42 keratoconus patients consecutively implanted with the Ferrara ICRS were evaluated with a Pentacam (Oculus Optikgerate GmbH). The following parameters were obtained: Anterior corneal asphericity (Q), CV and thinnest corneal thickness (TCT). The inter-relation between Q and CV was evaluated. Results In patients with CV inside two standard deviation (SD: 53.51-60.65) of the mean CV, the postoperative asphericity values roughly agreed with expected asphericity values. In patients with CV outside two SD intervals (&lt;53.51 and &gt;60.65) of the mean CV, the postoperative asphericity values did not agreed with expected asphericity values. Corneas with high volumes (&gt;60.65) had less change of asphericity than corneas with low volumes. Conclusion The CV is a new parameter, to be better studied, as it seems to be important in ICRS selection. Corneas with high volumes may require more tissue to get flattened and properly reshaped. How to cite this article Torquetti L, Ferrara G, Dias WG, Ferrara P. The Influence of Corneal Volume in Surgical Planning: Insights for a New Parameter for the Ferrara Ring Nomogram. Int J Kerat Ect Cor Dis 2013;2(1):12-15.

Intrastromal corneal ring segments: visual outcomes from a large case series

To evaluate the clinical safety and efficacy of implanted Ferrara intrastromal corneal ring segments in a large sample of patients with ectatic corneal disease. Retrospective, consecutive case series. A total of 1073 eyes of 810 patients consecutively operated from January 2006 to July 2008 were evaluated. Two groups were created according to the type of ring implanted: Group 1 - patients implanted with the 160° of arc ring - and Group 2 - patients implanted with the 210° of arc ring. Uncorrected visual acuity, best-corrected visual acuity, keratometry, asphericity and pachymetry at the thinnest point of the cornea. All patients were evaluated using a corneal tomography (Pentacam, Oculus, Inc., Lynnwood, WA, USA). For Group 1 patients, uncorrected visual acuity increased to 20/80, best-corrected visual acuity increased to 20/40, asphericity decreased to -0.35, spherical equivalent decreased to -2.26 D and keratometry decreased to 45.72 D (P < 0.001 for each compared with preoperative values). For Group 2 patients, uncorrected visual acuity increased to 20/130, best-corrected visual acuity increased to 20/60, asphericity decreased to -0.56, spherical equivalent decreased to -4.14 D and keratometry decreased to 48.10 D (P < 0.001 for each compared with preoperative values). The 210° intrastromal corneal ring segments reduced keratometry and asphericity more than the 160° intrastromal corneal ring segments did. The complication rate was 3.82%. Ferrara intrastromal corneal ring segments implantation is safe and effective and has a low complication rate. It can effectively reduce the corneal steepening and improve uncorrected visual acuity and best-corrected visual acuity in patients with keratoconus.

Corneal Collagen Cross-Linking Before Ferrara Intrastromal Corneal Ring Implantation for the Treatment of Progressive Keratoconus

To evaluate the safety, efficacy, and stability of sequential corneal collagen cross-linking (CXL) and Ferrara intrastromal corneal ring segment (FR) implantation in selected patients with progressive keratoconus. This prospective study involved 9 eyes with progressive keratoconus and a preoperative cylinder value equal to or greater than 5 diopters (D) diagnosed between June 2007 and October 2008. Preoperative and postoperative (6 months after the CXL procedure and 6 months after the FR implantation) biomicroscopy examinations, distance uncorrected and best-corrected visual acuities, refractive error, and topographic maps were evaluated and compared. Mean uncorrected visual acuity was 1.11 logarithm of the minimal angle of resolution (logMAR) preoperatively and 0.75 logMAR at 6 months after CXL (P = 0.03) and 0.23 logMAR at 6 months after FR implantation (P < 0.001). Mean best-corrected visual acuity was 0.26 logMAR preoperatively and 0.24 logMAR at 6 months after CXL (P = 0.87) and 0.12 logMAR at 6 months after FR (P = 0.05). Statistically significant reductions in the mean spherical equivalent (4.38 D; P < 0.001) and mean maximum (5.58 D; P < 0.001) and minimum (4.17 D; P < 0.001) keratometry values were present at 6 months after FR. FR implantation after CXL is a safe and efficacious treatment option for managing selected patients with progressive keratoconus. Good results in terms of visual acuity, postoperative residual refractive error, and keratometry values were obtained. Longer follow-up would be valuable to confirm the stability of these results.

Intrastromal corneal ring segment implantation to correct astigmatism after penetrating keratoplasty

To evaluate the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS) in patients with astigmatism after penetrating keratoplasty (PKP). Private clinic, Belo Horizonte, Brazil. Retrospective consecutive case series. Chart records of post-PKP patients who had ICRS implantation from May 2005 to September 2009 were retrospectively reviewed. The following parameters were studied: corrected distance visual acuity (CDVA), keratometry (K) values, spherical equivalent (SE), spherical refractive error, corneal topographic astigmatism, minimum K, and maximum K. The study evaluated 59 eyes (54 patients). The mean CDVA (logMAR) improved from 0.45 ± 0.17 (SD) (range 0.18 to 1.00) to 0.30 ± 0.17 (range 0.00 to 1.00). The mean SE was -6.34 ± 3.40 diopters (D) (range 0.37 to -16.50 D) preoperatively and -2.66 ± 2.52 D (range 0.87 to -10.50 D) postoperatively. The mean spherical refractive error decreased from -7.10 ± 3.07 D (range 2.15 to 16.68 D) preoperatively to -3.46 ± 2.05 D (range 0.88 to 10.79 D) postoperatively. No patient lost visual acuity. The mean corneal topographic astigmatism decreased from 3.37 ± 1.51 D preoperatively to 1.69 ± 1.04 D postoperatively. The mean maximum K value decreased from 48.09 ± 2.56 D to 44.17 ± 2.67 D and the mean minimum K value, from 44.90 ± 2.54 D to 42.46 ± 2.63 D. All changes were statistically significant (P<.0001). Intrastromal corneal ring segments effectively reduced corneal cylinder in patients with astigmatism after PKP.

Predictors of Clinical Outcomes after Intrastromal Corneal Ring Segments Implantation

ABSTRACT Purpose To evaluate the influence of age and severity of keratoconus in the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS). Methods A total of 1,073 eyes of 810 patients, consecutively operated from January 2006 to July 2008, were evaluated. Two independent analysis were made according to the age of patients and keratoconus staging. Four groups were created according to the age of patients: &lt; 20 years old, 20 to 30, 30 to 40 and &gt;40 years old. The patients were also evaluated according to the keratoconus stage (I to IV). The outcome analysis included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry (K), asphericity (Q), corneal volume (CV) and pachymetry. All patients were evaluated using the Pentacam. Results The postoperative increase in UDVA and CDVA was statistically significant in all groups (p &lt; 0.05). The magnitude of improvement of CDVA was larger for patients between 21 and 30-year-old (CDVA = 20/40) and patients with keratoconus grade I (CDVA = 20/35) (p &lt; 0.05). There was a statistically significant increase in CV and pachymetry postoperatively in all groups. The keratometry (3.95D) and asphericity (–0.77) reduction were larger in patients younger than 20-year-old and in patients with keratoconus grade IV (p &lt; 0.05). Conclusion The best clinical outcomes are seen in patients between 20 and 30-year-old and initial cases of keratoconus (grade I). The more advanced the keratoconus, the larger magnitude of K and Q reduction after ICRS implantation. How to cite this article Torquetti L, Ferrara G, Ferrara P. Predictors of Clinical Outcomes after Intrastromal Corneal Ring Segments Implantation. Int J Keratoco Ectatic Corneal Dis 2012;1(1):26-30.

Refractive and Visual Outcomes After Intacs vs Ferrara Intrastromal Corneal Ring Segment Implantation for Keratoconus: A Comparative Study

To evaluate the refractive, topographic, optical, visual acuity, and quality outcomes of two types of intrastromal corneal ring segments (ICRS) in the treatment of keratoconus. In this retrospective study, 16 eyes that had been implanted with Intacs ICRS (Addition Technology Inc) (Intacs group) and 17 eyes implanted with Ferrara ICRS (Ferrara Ophthalmics Ltda) (Ferrara group) were evaluated. Pre- and postoperative examinations included uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), manifest refraction, slit-lamp examination, topography, and ocular wavefront analysis. Contrast sensitivity measurements under photopic, scotopic, and scotopic with glare conditions were performed 1 year postoperatively. One year postoperatively, a significant decrease was noted in spherical equivalent refractive error of 3.76 ± 0.39 diopters (D) and 3.42 ± 0.88 D and keratometry of 3.43 ± 0.24 D and 3.28 ± 0.78 D in the Intacs and Ferrara groups, respectively; and increase in mean UDVA and CDVA in Snellen lines of 0.18 ± 0.04 and 0.21 ± 0.05, respectively, in the Intacs group and 0.21 ± 0.09 and 0.26 ± 0.08, respectively, in the Ferrara group (P<.01 for all). The postoperative increase in UDVA and CDVA and decrease in keratometry readings were not significantly different between groups (P>.05 for all). Mean higher order aberrations decreased in the Intacs group and increased in the Ferrara group (P>.05 for both). Postoperatively, a significant decrease was noted in scotopic contrast sensitivity when glare was introduced in the Ferrara group, which was positively correlated with pupil diameter (r(15)=0.50, P=.04). Both ICRS types provided comparable refractive, topographic, and optical quality outcomes. Eyes with Ferrara ICRS experienced greater decrease in scotopic contrast sensitivity under glare, which was significantly correlated with pupil diameter.

Preliminary results of intrastromal corneal ring segment implantation to treat moderate to severe keratoconus

To present our preliminary experience with implantation of Ferrara intrastromal corneal ring segments (ICRS) in keratoconus patients. Magrabi Eye and Ear Center, Jeddah, Saudi Arabia. Case series. This study comprised patients diagnosed with primary keratoconus who had ICRS implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities were recorded. The change in manifest refraction spherical equivalent (MRSE), mean refractive cylinder, average simulated keratometry (K), and topographic cylinder from preoperatively to 6 months postoperatively was analyzed, and complications were noted. The t test was used to compare 2 independent means and the Wilcoxon signed-rank test, to compare nonparametric data. By 6 months postoperatively, the CDVA was unchanged in 27% of cases and had improved between 1 line and 6 lines in 64% of cases; 9% of cases lost 1 or 2 lines. There was a decrease in the following mean values: MRSE (-3.60 diopters [D] ± 3.10 [SD] to -2.52 ± 3.10 D; P = .209); refractive cylinder (5.18 ± 2.10 D to 2.90 ± 2.50 D; P = .000); simulated K (51.16 ± 5.60 D to 48.11 ± 3.60 D; P = .000); topographic cylinder (5.30 ± 2.80 D to 3.80 ± 3.20 D; P = .000). For cases with a 24-month follow-up, stability was similar for all parameters. Intraoperative or postoperative complications occurred in 13% of cases; all were managed without clinically significant visual loss. Implantation of ICRS resulted in reasonable refractive and visual outcomes in a wide spectrum of keratoconus cases. The author has no financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes.

Intrastromal corneal ring segment implantation for ectasia after refractive surgery

To evaluate the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS) in patients with corneal ectasia after refractive surgery. Private clinic, Belo Horizonte, Brazil. Charts of patients with corneal ectasia after refractive surgery were retrospectively reviewed. The following parameters were studied: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal asphericity, and pachymetry. All patients were evaluated by Scheimpflug scanning-slit tomography (Pentacam). Twenty-five eyes (20 patients) with corneal ectasia (20 after laser in situ keratomileusis, 4 after radial keratotomy, 1 after photorefractive keratectomy) were evaluated. Postoperatively, the mean UDVA increased from 20/185 to 20/66 (P = .005) and the mean CDVA, from 20/125 to 20/40 (P = .008). The mean asphericity decreased from -0.95 preoperatively to -0.23 postoperatively (P = .006). The mean pachymetry at the apex of the cornea increased from 457.7 microm +/- 48.7 (SD) preoperatively to 466.2 +/- 49.8 mum postoperatively (P = .025) and the mean pachymetry at the thinnest point, from 436.3 +/- 46.2 microm to 453.9 +/- 49.3 microm (P = .000). The mean keratometry decreased from 45.41 +/- 5.63 diopters (D) to 42.88 +/- 4.44 D, respectively; the decrease was statistically significant (P = .000). Intrastromal corneal ring segment implantation significantly improved UDVA and CDVA in patients with corneal ectasia.