Corneal Ring Segments Research Articles

Same-Day Intrastromal Corneal Ring Segment and Collagen Cross-Linking for Ectasia after Laser In Situ Keratomileusis: Long-Term Results

To report the long-term results of combined same-day intrastromal corneal ring segment placement and corneal collagen cross-linking (CXL) for postoperative laser insitu keratomileusis (LASIK) ectasia. Retrospective, interventional case series. This retrospective, interventional cases series was performed in Turkiye Hospital Eye Clinic and the Department of Ophthalmology, Fatih University Medical Faculty Hospital, Istanbul, Turkey. Sixteen eyes of 14 patients with postoperative ectasia after LASIK were enrolled. All consecutive patients were treated with femtosecond laser-assisted intrastromal corneal ring segment implantation and followed by same-day corneal collagen cross-linking for ectasia occurring after LASIK. Main outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, spherical and cylindrical refraction, and simulated keratometry values. The mean age ± standard deviation of the 10 women and 4 men was 33.0 ± 6.5 years (range, 23 to 44 years), and the mean follow-up was 43months (range, 36 to 62months). The uncorrected distance visual acuity improved significantly from 1.18 ± 0.42 logarithm of the minimal angle of resolution (logMAR) units to 0.44± 0.22 logMAR (P < .001), and the corrected distance visual acuity improved significantly from 0.46 ± 0.26 logMAR to 0.21 ± 0.14 logMAR (P < .001). The mean spherical and cylindrical refraction decreased significantly (P < .001 for both). The maximum keratometry value decreased from baseline by 49.3 ± 4.9 diopters (D) to 43.9 ± 2.8 D at the last visit, and the minimum keratometry value decreased from 44.3 ± 4.7 D to 41.5 ± 3.5 D (P < .001 for both). No serious complications were shown during follow-up. Implantation of intrastromal corneal ring segment implantation combined with same-day corneal collagen cross-linking was a safe and effective treatment for ectasia occurring after LASIK. It also significantly improved the visual acuity, refraction, and keratometry values.

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.

How to improve Visual Acuity after Intrastromal Corneal Ring Segments? Implantation for Keratoconus and Post-LASIK Ectasia

ABSTRACT Keratoconus (KC) is an ecstatic corneal disease that causes irregular astigmatism which cannot be corrected by glasses, the irregular astigmatism causes loss of visual acuity (VA) both the uncorrected and the corrected VA, in addition to deterioration in the quality of vision. Contact lenses (CLs) improve the VA but cannot be tolerated in many cases due to several causes, such as loss of motivation, atopic and allergic conjunctivitis that are more frequently associated with KC and dry eyes. Intrastromal corneal ring segments implanted in keratoconic eyes improve uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), reduce myopia, astigmatism, high order aberrations (HOA) and regularizes the cornea (less irregular astigmatism), similar results are achieved in the treatment of post-LASIK and post PRK ectasia. These results were confirmed in long-term follow-up. The more advanced the KC the more is the effect of the ICRS but the less the functional VA achieved and vice versa. Thicker rings are more effective, and the smaller the optical zone the more is the effect of the ICRS. The aim of ICRS implantation in KC is not to be free of glasses or CL but to enable the patient of seeing with glasses or to tolerate CL in order to prevent or delay the need for penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK). In many cases, we can achieve a functional and satisfactory UCVA with no need for glasses and this is the case in nonadvanced KC but not in the advanced cases. In some cases, the results achieved need additional means to improve VA in order to get satisfactory VA. There are nonsurgical and surgical means to improve VA after ICRS, these means will be reviewed in this article. How to cite this article Barbara A, Barbara R. How to improve Visual Acuity after Intrastromal Corneal Ring Segments? Implantation for Keratoconus and Post-LASIK Ectasia. Int J Kerat Ect Cor Dis 2014;3(2):69-75.

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.

Intrastromal Corneal Ring Segment with and without Collagen Corneal Crosslinking vs Penetrating Keratoplasty for the Treatment of Keratoconus

ABSTRACT Keratoconus (KC) is a noninflammatory progressive corneal degeneration that cause irregular astigmatism especially in moderate and advanced cases, the irregular astigmatism can not be corrected by glasses, contact lenses are the only optical way for improving the visual acuity (VA) in these patients. In this retrospective study, we shall present the results of eight patients suffering from KC who were treated by PKP in one eye (PKP group) and ICRS (ICRS group) with or without CXL in the second eye. All the ICRS surgeries, the CXL and the PRK were performed at the I Vision, Refractive Surgery and Keratoconus Treatment Center in Haifa, Israel, by the same surgeon (AB), the PKPs were performed elsewhere, because they were treated in our medical center after the PKP. How to cite this article Barbara R, Barbara A. Intrastromal Corneal Ring Segment with and without Collagen Corneal Crosslinking vs Penetrating Keratoplasty for the Treatment of Keratoconus. Int J Kerat Ect Cor Dis 2014;3(2):88-94.

Decision making nomogram for intrastromal corneal ring segments in keratoconus

Purpose:To create a nomogram for the insertion of intrastromal corneal ring segments (ICRS) (Intacs® ) in eyes with keratoconus.Setting:Tertiary eye care center in South India.Materials and Methods:This prospective, non-randomized, interventional case series used a self-designed decision-making nomogram for the selection of ICRS in keratoconus patients based on the centration of the cone, mean refractive spherical equivalent (MRSE), and mean keratometry (Km) values. The 3, 6, and 12 months clinical outcomes were compared to historical controls. Primary endpoints were improvement in uncorrected and best-corrected vision and change in the keratometric values.Results:Group A comprised of 52 eyes of 50 patients that followed the nomogram, while Group B comprised of 25 eyes of 23 non-nomogram historical controls matched for baseline parameters. In Group A, the uncorrected distance visual acuity (UDVA) improved from 0.16 ± 0.15 to 0.25 ± 0.16 (P < 0.001), corrected distance visual acuity (CDVA) from 0.58 ± 0.2 to 0.69 ± 0.21 (P = 0.022), MRSE from -5.41 ± 4.94 to -1.71 ± 2.88 (P < 0.001), Km from 51.77 ± 5.45 to 48.63 ± 4.37 (P < 0.001), and astigmatism reduced from 5.86 ± 2.61 to 4.91 ± 2.72 diopters (P < 0.001).In Group B, improvement in the average MRSE was from -6.44 ± 5.32 to -3.26 ± 2.82 (P < 0.013) and in the average Km from 53.64 ± 5.32 to 50.31 ± 5.02 (P < 0.001). Other parameters did not improve significantly. A statistically significant difference was present in the percentage of patients achieving a good clinical outcome between the two groups (P < 0.001; Chi-square).Conclusion:The nomogram provides a means to choose the appropriate ICRS, hence improving the outcome in patients with keratoconus.

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: How successful is the surgical treatment of keratoconus?

This review evaluates the outcomes of intrastromal corneal ring segment (ICRS) implantation for the treatment of keratoconus considering a new grading system based on the preoperative visual impairment of the patient. Additionally, a five-year follow-up analysis of patients with stable and progressive keratoconus is performed in order to assess the long term stability of the surgical procedure. Corrected distance visual acuity decreased statistically significantly in patients with mild keratoconus (P < 0.01) but statistically significantly increased in all other grades (P < 0.05). The improvement in visual acuity and the decrease of keratometric and aberrometric values were stable throughout a long period of time in patients with stable keratoconus. In patients with progressive form keratoconus, a significant improvement was found immediately after the procedure, however clinically relevant regression greater than 3 D was observed at the end of the follow up period.

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.

Intracorneal Ring Segment Explantation After Intracorneal Ring Segment Implantation Combined With Same-Day Corneal Collagen Crosslinking in Keratoconus

To report the outcome and the reversibility of refractive outcomes after intrastromal corneal ring segment (ICRS) explantation in patients with keratoconus treated with ICRS implantation and same-day collagen crosslinking (CXL). This is a retrospective review of ICRS explantation in 3 eyes of 3 patients with keratoconus that had undergone femtosecond laser-enabled placement of paired ICRS (Intacs) with same-day CXL by a single surgeon between 2008 and 2011. The main outcome measures included baseline/preexplantation/postexplantation visual acuity, refractive error, keratometry, and higher order aberrations. None of the patients lost best-corrected distance visual acuity lines. ICRS can be safely and easily explanted from keratoconic eyes with previous CXL. Some of the topographic benefits gained from ICRS implantation may persist after explantation. Despite the reversal of refractive outcomes, the preservation of topographic changes may occur in some cases after the explantation of 1 or both the segments in patients with keratoconus treated with ICRS implantation with same-day CXL.

Lathed soft toric contact lenses fitting after intrastromal corneal ring segments implantation in 40 keratoconic eyes at different stages

Purpose: To demonstrate the feasibility of lathed toric contact lens fitting on Keratoconus patients at different stages with Keraring Intrastromal Corneal Ring Segments (ICRS) implantation (Mediphacos, Brazil).

Management of post-LASIK keratectasia with a piggyback contact lens system

Purpose: This case report highlights the clinical challenges involved in the management of a patient with post-LASIK keratectasia and reviews the various treatment options for iatrogenic keratoconus. A single case is presented with a focus on contact lens fitting and management of concurrent ocular surface disease.Although the patient was successfully fitted with large diameter corneal gas permeable lenses, the interference of pre-existing atopic disease combined with post-LASIK dry eye induced a compromised ocular surface requiring a therapeutic bandage piggyback lens. A review of the literature indicates that current screening methods prior to refractive surgery have made improvements for detecting patients at higher risk of serious complications. However, as this case illustrates, previous guidelines were inadequate in identifying incipient keratoconus. Possible treatment options for iatrogenic keratoconus, one of the most severe refractive surgery complications, include contact lenses, intrastromal corneal ring segments, corneal cross linking, and keratoplasty. This case report demonstartes that post- LASIK keratectasia with concurrent ocular surface disease can be successfully managed with the use of a piggyback contact lens system.

Femtosecond laser–assisted intrastromal corneal ring segment implantation for high astigmatism correction after penetrating keratoplasty

To assess the visual and refractive outcomes of femtosecond laser-assisted implantation of Ferrara-type intrastromal corneal ring segments (ICRS) in post-penetrating keratoplasty (PKP) eyes. Instituto Oftalmológico Fernández-Vega, Oviedo, Spain. Cohort study. Patients with previous PKP had ICRS implantation after femtosecond laser tunnel creation. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities and residual refractive errors were recorded before and 6 months after ICRS implantation. The power vector method was used to analyze refractive errors preoperatively and postoperatively. This study enrolled 32 eyes of 30 patients. The mean UDVA (Snellen decimal) changed from 0.16 ± 0.15 (SD) preoperatively to 0.43 ± 0.28 postoperatively (P<.0001). Postoperatively, the UDVA was 20/40 or better in 40.6% of eyes. The mean CDVA was 0.67 ± 0.22 preoperatively and 0.80 ± 0.19 postoperatively (P<.0001). Postoperatively, the CDVA was better than 20/40 in 96.9% of eyes and 20/25 or better in 56.2% of eyes. By 6 months postoperatively, no eye had lost more than 2 lines of CDVA, 4 eyes lost 1 line, 6 eyes had no change, 9 eyes gained 1 line, and 13 eyes gained 2 or more lines. The safety index at 6 months was 1.20. The spherical equivalent and astigmatism components were significantly reduced after ICRS implantation (P<.04). Intrastromal corneal ring segment implantation using the femtosecond laser may be a good alternative for high astigmatism correction in post-PKP eyes.

Comparison of Intrastromal Corneal Ring Segment Implantation only and in Combination with Collagen Crosslinking for Keratoconus

To compare visual outcomes, corneal astigmatism, and keratometric readings in patients with progressive keratoconus undergoing intrastromal corneal ring implantation (ICRSI) only and in combination with ultraviolet A riboflavin mediated corneal collagen crosslinking (CXL). In this retrospective comparative study, there were 2 groups of keratoconus patients. Group 1 consisted of only ICRSI patients. Group 2 consisted of combined ICRSI-CXL patients. Preoperative and postoperative uncorrected distance visual acuity (UCDVA) and best-corrected distance visual acuity (BCDVA), spherical error, cylindrical error, and mean keratometry were compared. The study evaluated 166 eyes of 121 patients with a mean age of 24.74 years. The UCDVA improved from 0.24 to 0.37 in group 1 and from 0.24 to 0.42 in group 2 at the last visit. The BCDVA improved from 0.34 to 0.62 in group 1 and from 0.31 to 0.67 in group 2. Spherical error decreased from -5.05 D to -1.65 D in group 1 and from -4.82 D to -1.52 D in group 2. Cylindrical error decreased from -6.06 D to -3.47 D in group 1 and from -5.66 D to -3.20 D in group 2. Mean keratometry values decreased from 51.89 D to 47.96 D in group 1 and from 50.89 D to 46.91 D in group 2. p Value was >0.05 in group comparisons. Ring explantation due to corneal melting was applied in 3 eyes. Both combined ICRSI-CXL and ICRSI-only groups experienced favorable outcomes, without statistical difference in any studied effect of both treatment strategies.

Intrastromal corneal rings and corneal collagen crosslinking for progressive keratoconus: Comparison of 2 sequences

AbstractPurpose To compare 2 sequences of combined intrastromal corneal ring segment (ICRS) implantation and corneal collagen crosslinking (CXL) in progressive keratoconus.Methods In this retrospective study, CXL was followed by ICRS implantation (group A) or ICRS implantation was followed by CXL (group B). Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, spherical equivalent (SE), manifest cylinder and mean keratometry (K) were compared preoperatively and postoperatively.Results 17 eyes of 10 patients with progressive keratoconus were included in this study, 11 eyes in group A and 6 in group B. The mean interval between treatments was 4.3+/‐2.9 months in group A and 5+/‐4.4 months in group B. The mean age is 27.6 years in group A and 28.4 years in group B. The 2 groups are equivalent preoperatively. The mean UDVA and CDVA improved in both groups (UDVA:0.50+/‐0.22 to 0.60+/‐0.20, group A, and 0.28+/‐0.19 to 0.62+/‐0.22(p&lt;0.05), group B; CDVA:0.60+/‐0.15 to 0.70+/‐0.14 and 0.70+/‐0.14 to 0.88+/‐0.17 respectively). The cylinder and mean k values decreased in both groups (cylinder ‐3.63D+/‐1.27 to ‐0.95D+/‐1.54 (p&lt;0.05), group A and ‐3.60D+/‐1.85 to ‐2.80D+/‐2.19 group B; mean K:44.8+/‐1.45 to 42.8D+/‐1.7 (p&lt;0.05) and 43.98+/‐1.74 to 43.8D+/‐1.8, respectively). SE: values decreased in group A (‐3.4D+/‐1.5 to ‐1.3D+/‐1.4 (p&lt;0.05)) instead increased in group B (‐1.1D+/‐0.8 to ‐1.7D+/‐1.0). Overall, the 2 sequences observed show an improvement in UDVA, CDVA, cylinder and mean K.Conclusion In our study, there is no statistical difference between the 2 sequences: ICRS implantation followed by CXL or CXL followed by ICRS implantation.

Evolution in the use of intrastromal corneal ring segments for corneal ectasia

To report the recent advances in the use of intrastromal corneal ring segments (ICRS) for treating patients with corneal ectasia. ICRS improve visual, refractive, and keratometric parameters in patients with keratoconus and postlaser in-situ keratomileusis ectasia. ICRS have been made safer, quicker, and more precise with the use of femtosecond lasers for ring insertion. ICRS produce better visual outcomes in patients with poor preoperative corrected distance visual acuity compared with patients with less preoperative visual impairment. Standard ICRS do not improve vision in patients with stage 3-4 keratoconus (Amsler-Krumeich classification), but newer models of ICRS, such as Intacs SK, appear promising for these patients. ICRS have been successfully combined with treatments such as corneal collagen cross-linking (CXL), penetrating keratoplasty, and photorefractive keratectomy. ICRS variably improve visual acuity. Numerous questions concerning ICRS remain, including the duration of the effects of ICRS and the changes that ICRS induce on a biomechanical level. The optimal method for combined CXL and ICRS placement has not yet been determined. Further well-designed randomized controlled studies with long-term follow-up are needed for clarification.

Intra-Stromal Corneal Ring Segments

Intra-stromal corneal ring segments (ICRs) are a new modality in the treatment of corneal ectactic disorders like keratoconus, post lasik ectasia and pellucid marginal degeneration. ICRS is a minimally invasive technique wherein the central optical zone is not disturbed with long term convenient refractive correction. Two brands of ICRS segments are popular commercially, Intacs (Additions Technology Inc) and Ferrara Rings. ICRS reduces the sphere, cylinder and the spherical equivalent in keratoconus. Pre-operative evaluation and patient selection plays a key role in the success of the implant. The determination of which segment to implant depends upon pre-operative manifest refraction, spherical equivalent, location of the cone and degree of asymmetric astigmatism. ICRS along with collagen cross linking has opened new vistas in the treatment of keratoconus and corneal ectasia. While cross linking stops the progression of the ectasia and reverses it to some extent, ICRS flatten or normalize the corneal shape. Combining both the modalities together has a synergistic action and can be performed simulatneously or sequentially. Complications are rare as ICRS implantation is reversible, no corneal tissue is removed, and the central optical zone is not invaded.

Efficacy of single or paired intrastromal corneal ring segment implantation combined with collagen crosslinking in keratoconus

To evaluate the efficacy of single or paired intrastromal corneal ring segments (ICRS) combined with ultraviolet-A and riboflavin collagen crosslinking (CXL) in patients with keratoconus. Cornea Unit, Toronto Western Hospital, Toronto, Ontario, Canada. Retrospective comparative case series. Consecutive patients with keratoconus had femtosecond laser-assisted ICRS implantation combined with same-day CXL between 2008 and 2011. The main outcome measures included improvement in visual acuity, subjective refractive error, keratometry values, and total higher-order aberration (HOA). Eighty-five eyes of 74 patients with keratoconus (paired ICRS: 47 eyes of 40 patients; single ICRS: 38 eyes of 34 patients) were included in the study. The uncorrected distance visual acuity was significantly improved after single ICRS (3.4 lines; P=.04) and paired ICRS (2.7 lines; P=.01) implantation combined with CXL, while corrected distance visual acuity (CDVA) remained stable. The single and paired ICRS groups had a significant reduction in mean cylinder at 1 year (single ICRS: -3.84 diopters [D] ± 1.72 [SD] versus -2.19 ± 1.54 D, P=.02; paired ICRS: -3.91 ± 1.45 D versus -2.96 ± 1.92 D) (P=.02). There was no significant difference in total HOAs. Single ICRS implantation and paired ICRS implantation with CXL were equivalent in all refractive parameters. No patient lost lines of CDVA. As determined by corneal topography, implantation of single or paired ICRS combined with same-day CXL was safe and effective in patients with keratoconus.

Outcomes of intrastromal corneal ring segments for treatment of keratoconus: Five-year follow-up analysis

To report the long-term refractive and optical quality outcomes of patients with intrastromal corneal ring segments (ICRS) to treat keratoconus and to analyze the results according to the patients' age. Vissum Instituto Oftalmologico de Alicante, Alicante, Spain. Case series. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, corneal topography, and aberrometry were evaluated before and after ICRS implantation in eyes with keratoconus. The follow-up was 5 years in all cases. The study comprised 51 eyes (35 patients; age range 15 to 56 years). After 6 months, the improvement in the UDVA, CDVA, spherical equivalent, and mean keratometry (K) value was statistically significant (P<.05). Five years postoperatively, these parameters remained unchanged (P=.31). Slight regression (0.97 diopter [D]) was observed in the mean K between 6 months and 5 years; the regression was not statistically significant (P=.39). Anterior corneal aberrometric values decreased; however, the changes were not statistically significant (P ≥.10). Linear regression analysis showed no correlation between the age of the patients and the changes observed in the mean K throughout the follow-up (P>.05, r(2) = 0.001). Intrastromal corneal ring segment implantation in keratoconus patients provided long-term improvement of the refractive and topographic status. There was no correlation between the amount of individual changes in the mean K reading and patient age.

Intacs with or without same-day corneal collagen cross-linking to treat corneal ectasia

ObjectiveTo compare combined intrastromal corneal ring segment implantation with same-day ultraviolet-A/riboflavin corneal collagen cross-linking (ICRS-CXL) versus ICRS implantation alone in patients with corneal ectasia. DesignRetrospective comparative study. ParticipantsSixty-six eyes from 54 patients with corneal ectasia were included in the study. The groups were composed of 32 eyes from 27 patients and 34 eyes from 27 patients for the ICRS-CXL and ICRS groups, respectively. MethodsWe reviewed the charts of all patients who underwent these procedures from November 2008 to February 2011 for preoperative and for up to 1 year postoperative uncorrected (UDVA) and best corrected distance visual acuity (BDVA), refraction, topographical analysis (mean and steepest keratometry [K]), as well as root mean-square (RMS) of higher-order aberrations (HOAs). ResultsOverall, a significant improvement was seen in both groups for UDVA, BDVA, sphere, cylinder, mean refractive spherical equivalent (MRSE), mean and steepest K, coma, spherical and total HOA at 12 months. Trefoil did not improve, and higher-order astigmatism worsened in the ICRS group (p = 0.0466). There was no statistically significant difference between the 2 groups for visual acuity, sphere, cylinder, coma, trefoil, and spherical HOA. Outcomes were significantly more improved in the ICRS group for MRSE (p = 0.0082), mean K (p = 0.0021), steepest K (p = 0.0152), and total HOAs (p = 0.0208). No complications were observed. ConclusionsICRS-CXL and ICRS alone were both safe and effective in treating corneal ectasia. The ICRS alone group demonstrated better outcomes of MRSE, mean and steepest K, as well as total HOA.