Forward light scatter and visual acuity before and after intrastromal corneal ring segment implantation at different stages of keratoconus

Importance: This study shows that a newer long-arc length intrastromal corneal ring segment is efficient and safe for keratoconus treatment. Background: To evaluate visual, tomographic results and complications of a 320-degree intrastromal corneal ring segment implantation with the femtosecond laser for keratoconus treatment. Design: A prospective, nonrandomized, and interventional study. Participants: A total of 34 eyes of 31 patients diagnosed with keratoconus were enrolled. Methods: Patients were divided into two groups based on the strategy used for 320-degree intrastromal corneal ring segment thickness selection. In one group, this selection was based on spherical equivalent (SE group) and in the other on the mean asphericity (Q group). The uncorrected and corrected distance visual acuities, spherical equivalent, K1, K2, Km, Kmax, and mean asphericity ( Q) on corneal tomography were evaluated preoperatively and at 3 and 6 months postoperatively. For astigmatism improvement, we analyzed the corneal tomographic vectorial astigmatism change preoperatively and at 6 months postoperatively. The mean follow-up period was 6.63 ± 0.96 months. Results: The mean uncorrected distance visual acuity and corrected distance visual acuity improved with a significant spherical equivalent improvement ( p < 0.05), with no differences between the 320-degree intrastromal corneal ring segment groups. All corneal tomographic parameters improved significantly ( p < 0.05) between the preoperative and postoperative intervals, with a significant better performance when we used spherical equivalent for the 320-degree intrastromal corneal ring segment thickness selection. Finally, the mean vectorial corneal tomographic astigmatism significantly improved after 6 months, again with no differences between groups. Conclusion: This study suggests that implanting a 320-degree intrastromal corneal ring segment is a safe and effective procedure for treating patients with keratoconus. It also suggests that for thickness selection spherical equivalent is the better strategy.

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Influence of scleral lenses on visual acuity and aberrations in patients with irregular cornea

The Eye ◽

10.33791/2222-4408-2019-2-32-39 ◽

2019 ◽

Vol 126 (2019-2) ◽

pp. 32-39

Author(s):

Olga Tikhonova ◽

Nikolai Pashtaev ◽

Nadezhda Pozdeyeva ◽

Alexander Myagkov ◽

Svetlana Bodrova ◽

...

Keyword(s):

Visual Acuity ◽

Laser Surgery ◽

Contact Lenses ◽

Lens Space ◽

Astigmatism Correction ◽

Intrastromal Corneal Ring ◽

Stable Vision ◽

Ring Segment ◽

Ophthalmologic Examination ◽

Fitting In

Purpose: To analyze changes of functional parame¬ters and aberrations before fitting and after using rigid gas-permeable scleral lenses (RGPSCL) in patients with irregular cornea. Material and methods. 21 patients (29 eyes) with irregular astigmatism of various etiology were enrolled in this study. The patients could not achieve good visual aсuity in glasses, standard soft or rigid corneal contact lenses. Complex ophthalmologic examination was per¬formed: autorefractometry, visometry, biomicroscopy, computer corneal topography, aberrometry on “OPD-Scan II” (“Nidek”, Japan) before fitting scleral lenses and during the period of their wearing. Results and discussion. The results demonstrat¬ed significant visual acuity improvement after RGP¬SCL fitting in all observed patients. UCVA amounted to 0.1±0.18, BCVA in glasses amounted to 0.4±0.26, BCVA in RGPSCL amounted to 0.7±0.1. An increase of best-corrected visual acuity in RGPSCL was statistically significant in patients after keratoplasty, after intra-stromal corneal ring segments (ICRS) implantation, af¬ter refractive laser surgery (RLS) and in cases of mixed astigmatism. We have found that the correction of ker¬atoconus with the use of RGPSCL resulted in a decrease of the root mean square value (RMS), measured in the 3 mm and 5 mm zones by 2.5 times and 4 times, re¬spectively. In patients wearing RGPSCL after kerato¬plasty, statistically significant decrease in RMS was observed in the 3 mm zone (by 3.85 times) and in the 5 mm zone (by 2.99 times). In patients wearing RGPSCL after implantation of intrastromal corneal ring segment (ICRS), RMS in the 3 mm zone decreased by 1.5 times. In patients wearing RGPSCL after refractive laser surgery (RLS) RMS was 2.5 times lower in the 3 mm zone and 2.8 times lower in the 5 mm zone. In case of mixed astigmatism correction with RGPSCL, RMS increased by 1.6 times in the 3 mm zone and practically did not change in the 5 mm zone. Conclusion. The results obtained demonstrated significant visual acuity improvement in all observed patients. The sub-lens-space filled with tear forms a unified “cornea-tear-scleral contact lens” optic system that corrects unevenness of cornea, decreases amount of high-order aberrations (HOA) and provides a clear stable vision.

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Safety and effectiveness of intrastromal corneal ring segment implantation at Al-Dharan Eye Specialist Hospital, Al-Dharan, Saudi Arabia

International Surgery Journal ◽

10.18203/2349-2902.isj20191265 ◽

2019 ◽

Vol 6 (4) ◽

pp. 1295

Author(s):

Abdulaziz Alaqsam ◽

Mohanna AL-Jindan ◽

Ammar Almahmod ◽

Ibrahim Gosadi

Keyword(s):

Visual Acuity ◽

Saudi Arabia ◽

Case Series ◽

Applanation Tonometry ◽

Retrospective Case ◽

Intrastromal Corneal Ring ◽

Case Series Study ◽

Ring Segment ◽

The Mean ◽

One Year

Background: Intrastromal corneal ring segment (ICRS) implantation is one of the treatment options of keratoconus. This study is aiming to evaluate safety and effectivness of ICRS implantation at Al-Dharan Eye Specialist Hospital.Methods: This study is a descriptive retrospective case series study. The target population of this study is patients diagnosed with corneal ectasia who underwent ICRS implantation in Al-Dharan Eye Specialist Hospital, Al-Dharan, Saudi Arabia. Preoperative and postoperative data about uncorrected visual acuity (UCVA), best spectacle–corrected visual acuity (BSCVA), manifest refraction, keratometry, applanation tonometry, corneal topography, and slit-lamp biomicroscopy and indirect ophthalmoscopy were retrieved from medical records of department of Medical Archive. Paired students t-test was used to compare preoperative and postoperative means of study variables.Results: The total number of recruited patients in this study was 57 patients where 62% of them were males. Sixty-six treated eyes were included in this study where no intra-operative complications were recorded. Upon comparing the mean preoperative data to the mean postoperative data at three months, six months and one year intervals, an overall improvement in the measured outcomes was witnessed. UCVA, BSCVA, and keratometric readings exhibited a statistically significant improvement when comparing preoperative with one-year postoperative findings (p<0.001).Conclusions: The findings of this study indicate that ICRS implantation is a safe and effective treatment for keratoconus.

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Outcomes of a Single-Segment Intrastromal Corneal Ring in Early Keratoconus Versus Early Pellucid Marginal Degeneration

10.21203/rs.3.rs-471860/v1 ◽

2021 ◽

Author(s):

Seyed Javad Hashemian ◽

Parya Abdolalizadeh ◽

Leila Ghiasian ◽

Hossein Aghaei ◽

Ali Hadavandkhani ◽

...

Keyword(s):

Visual Acuity ◽

Femtosecond Laser ◽

Early Stage ◽

Interventional Study ◽

Short Term ◽

Single Segment ◽

Corrected Visual Acuity ◽

Intrastromal Corneal Ring ◽

Ring Segment ◽

Outpatient Center

Abstract Purpose: To determine the effect of a single-segment intrastromal corneal ring segment (ICRS;Intacs-SK) on early keratoconus (KCN) or pellucid marginal degeneration (PMD).Methods: It is a prospective interventional study. One-hundred-twenty-four eyes (99 patients) with KCN and 36 eyes (26 patients) with PMD at early stage (the maximum keratometric reading less than 55 diopters) were included to ICRS implantation using femtosecond laser at a tertiary university-based hospital and a private outpatient center. The uncorrected distance and spectacle-corrected visual acuity (UDVA and SCDVA), manifest spherical and cylindrical refractions, and keratometry indices were measured preoperatively and postoperatively, 1 week, 2 and 6 months.Results: One week after surgery, significant improvements were observed in UDVA, SCDVA, cylinder and keratometry readings of both KCN and PMD groups (all P<0.05) with no significant changes afterwards. No significant change occurred in the sphere refraction of PMD group (P=0.10) in contrast to KCN group (P<0.001). Corneal irregularity of KCN group in central 3 and 5 mm zones increased at 1 week (both P<0.001) and then continued to decrease up to 6 months. However, the corneal irregularity of PMD group had significant reduction only at 1 week in 5-mm zone (P=0.02) and 2 months in 3-mm zone (P=0.01) postoperatively. The final efficacy indexes were 1.44±0.71 and 0.87±0.40 in KCN and PMD groups, respectively. Conclusion: Visual acuity and keratometry values reached stability at 1 week, after one-segment Intacs-SK implantation in KCN and PMD groups. The short-term efficacy of the procedure was more in early KCN compared to early PMD.

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Corneal collagen cross-linking with and without simultaneous intrastromal corneal ring segment implantation: One-year pilot study

European Journal of Ophthalmology ◽

10.1177/1120672119887874 ◽

2019 ◽

pp. 112067211988787 ◽

Cited By ~ 1

Author(s):

Indra Prasad Sharma ◽

Ramendra Bakshi ◽

Monica Chaudhry

Keyword(s):

Visual Acuity ◽

Confidence Interval ◽

Randomized Study ◽

Cross Linking ◽

Intrastromal Corneal Ring ◽

Ring Segment ◽

One Year ◽

Collagen Cross Linking ◽

Corneal Collagen

Aim: The aim of this study was to assess and compare the visual, refractive, and topographic outcomes of keratoconic eyes treated with corneal collagen cross-linking combined with and without same day intrastromal corneal ring segment over the first 12 months. Methods: This prospective randomized study analyzed 38 eyes of 30 consecutive keratoconus patients aged 26.21 ± 6.97 (range = 15–41) years. A total of 20 eyes were treated with collagen cross-linking alone, and 18 eyes underwent collagen cross-linking combined with simultaneous femtosecond laser-assisted intrastromal corneal ring segment. Visual acuity, manifest refraction, and corneal topography (using a rotating Scheimpflug topographer) were assessed and compared between the two groups at baseline, 6, and 12 months. Results: On an average follow-up duration of 12.2 ± 0.50 (range = 11–13) months, both collagen cross-linking alone and collagen cross-linking with simultaneous intrastromal corneal ring segment implantation were effective. However, collagen cross-linking plus intrastromal corneal ring segment resulted in an additional improvement of uncorrected distance visual acuity of 0.16 (95% confidence interval = 0.01 to 0.32) logarithm of the minimum angle of resolution units (p = 0.035), cylindrical power by 1.16 D (95% confidence interval = 0.25 to 2.06, p = 0.014), and spherical equivalent by 1.40 D (95% confidence interval = −2.71 to −0.08, p = 0.038) at 1 year. During the study period, no serious intraoperative or postoperative complications were noted in either group. Conclusion: One-year follow-up results suggest that collagen cross-linking with simultaneously combined intrastromal corneal ring segment implantation could yield an additive visual and refractive outcome. The combined procedure is safe and merits consideration for the treatment of progressive keratoconus to achieve better visual rehabilitation.

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Assessment of Epithelial Thickness in Keratoconic Patients Before and After Intracorneal Ring Segment Implantation Using Anterior Segment Optical Coherence Tomography

QJM ◽

10.1093/qjmed/hcaa058.004 ◽

2020 ◽

Vol 113 (Supplement_1) ◽

Author(s):

R F Mohamed ◽

R M F Elghazawy ◽

S M Fawzy ◽

T A Badran

Keyword(s):

Visual Acuity ◽

Anterior Segment ◽

Case Series ◽

Treatment Modalities ◽

Ophthalmological Examination ◽

Epithelial Thickness ◽

Case Series Study ◽

Before And After ◽

Ring Segment ◽

Intracorneal Ring Segment

Abstract Background Keratoconus, the most common primary corneal ectasia, is a bilateral asymmetric corneal degeneration accompanied with local corneal thinning and occurs mostly in the inferior and central part of the cornea, it usually causes high myopia and irregular astigmatism which results in poor quality of vision. Based on disease severity, many treatment modalities exist including glasses and contact lenses for mild to moderate disease, while corneal graft preserved for more advanced disease. In advent of alternative treatments, intrastromal ring implantation have been introduced which improves visual acuity and optical aberrations and also corrects refractive errors and mean keratometric data, anterior segment Optical cohehernce Tomography epithelial mapping is anew modality to assess epithelial thickness. Objective: To investigate epithelial thickness changes in keratoconic patients before and after intracorneal ring segment implantation using AS OCT. Methods: Thirty eyes with early to moderate keratoconus were included in this prospective interventional case series study which has been conducted at patients from Ain shams university hospitals, after the approval of the research ethical committee in the Faculty of Medicine, Ain Shams University between March to October. All cases underwent a Complete ophthalmological examination before surgery. the examination included Visual acuity assessment and Best corrected visual acuity. Slit Lamp Biomicroscopy examination with fundus examination through dilated pupil using D lens & Corneal Topography, Anterior segment Optical cohehernce Tomography Epithelial mapping(zeiss). Results: we found that epithelial thickness showing statistically significant change comparing pre and post operative epithelial mapping especially in certain areas in the map,area ( _ ),( _ ) mm. Conclusion: There is increase in epithelium thickness in keratoconic corneas after intracorneal ring segment implantation to compensate for stromal irregularities in patients with keratoconus.

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Intrastromal Corneal Ring Segment Implantation (Keraring 355°) in Patients with Central Keratoconus: 6-Month Follow-Up

Journal of Ophthalmology ◽

10.1155/2015/916385 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 14

Author(s):

Khosrow Jadidi ◽

Seyed Aliasghar Mosavi ◽

Farhad Nejat ◽

Mostafa Naderi ◽

Leila Janani ◽

...

Keyword(s):

Visual Acuity ◽

Invasive Procedure ◽

Cost Effective ◽

Corrected Visual Acuity ◽

Intrastromal Corneal Ring ◽

Uncorrected Visual Acuity ◽

Ring Segment ◽

Efficacy Index ◽

Preliminary Study

We evaluate the efficacy and safety of Keraring 355° intrastromal corneal ring segment (ICRS) implantation aided by PocketMaker microkeratome for the correction of keratoconus. Patients underwent ICRS insertion using mechanical dissection with PocketMaker microkeratome and completed 6 months of follow-up. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), refraction, topographic findings, safety, efficacy index, and adverse events were reported for six months postoperatively. We evaluated 15 eyes of 15 patients (12 men) with a mean age of 28.87 ± 6.94 years (range 21–49 years). At final postoperative examination, there was a statistically significant reduction in the spherical equivalent refractive error compared to preoperative measurements (−5.46 ± 1.52 to −2.01 ± 1.63 D,P<0.001). Mean preoperative UCVA (logMAR) before implantation was 0.79 ± 0.48, and postoperative UCVA was 0.28 ± 0.15,P=0.001. Mean preoperative BSCVA (logMAR) before implantation was 0.36 ± 0.21; at final follow-up examination BSCVA was 0.18 ± 0.9,P=0.009. MeanKdecreased from 48.33 to 43.31 D,P<0.001. All patients were satisfied with ICRS implantation; 86.7% were moderately to very happy with the results. No intraoperative or postoperative complications were demonstrated. This preliminary study shows that ICRS (Keraring 355°) implantation is an efficient, cost-effective, and minimally invasive procedure for improving visual acuity in nipple type keratoconic corneas.

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Intrastromal corneal ring segment implantation in paracentral keratoconus with perpendicular topographic astigmatism and comatic axis

European Journal of Ophthalmology ◽

10.1177/1120672120952346 ◽

2020 ◽

pp. 112067212095234

Author(s):

Luis Fernández-Vega-Cueto ◽

Carlos Lisa ◽

Belén Alfonso-Bartolozzi ◽

David Madrid-Costa ◽

José F Alfonso

Keyword(s):

Statistical Significance ◽

Arc Length ◽

Refractive Outcomes ◽

Group I ◽

Intrastromal Corneal Ring ◽

Before And After ◽

Ring Segment ◽

Group Ii ◽

Topographic Astigmatism

Purpose: To evaluate the outcomes of implanting intrastromal corneal ring segment (ICRS) using two different strategies in a specific paracentral keratoconus phenotype. Methods: Eighty-nine eyes with paracentral keratoconus with perpendicular topographic astigmatism and comatic axes were evaluated before and after implanting a 150° arc-length ICRS. Patients were divided into two groups according to the axis where the ICRS was implanted: Group I: comatic axis and Group II: flat topographic axis. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refractive errors, and root mean square (RMS) for coma-like aberration were recorded. The postoperative follow-up was 1 year. Results: Mean UDVA (logMAR) changed from 0.49 ± 0.37 preoperatively to 0.30 ± 0.32 6 months afterwards ( p < 0.001) in the group I and from 0.53 ± 0.34 to 0.37 ± 0.35 ( p < 0.001), in the group II. Mean CDVA in group I changed from 0.11 ± 0.18 preoperatively to 0.06 ± 0.14 6 months after surgery ( p < 0.001). In group II the improvement did not reach statistical significance (from 0.09 ± 0.10 to 0.07 ± 0.09; p = 0.06). No eyes lost lines of CDVA in group I. Eight eyes (15.7%) lost lines of CDVA in group II. The spherical equivalent decreased after surgery in both groups ( p < 0.001). The RMS for corneal coma-like aberration only decreased in the group I ( p < 0.001). Conclusion: Both strategies provided safe and effective visual and refractive outcomes in the specific keratoconus phenotype analyzed. The orthopedic strategy provided better visual outcomes than the refractive one.

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Modification of the Intrastromal Ring Position according to Postimplant Visual and Refractive Failure: Report of Two Cases

Case Reports in Ophthalmological Medicine ◽

10.1155/2019/7151849 ◽

2019 ◽

Vol 2019 ◽

pp. 1-5

Author(s):

Luis Izquierdo ◽

Josefina A. Mejías Smith ◽

Jose R. Lievano ◽

Ramón Sarquis ◽

Maria A. Henriquez

Keyword(s):

Visual Acuity ◽

Postoperative Outcome ◽

Mean Square ◽

Corrected Visual Acuity ◽

Intrastromal Corneal Ring ◽

Scheimpflug Imaging ◽

Uncorrected Visual Acuity ◽

Ring Segment ◽

One Year ◽

Ring Position

Objective. The following report presents the adaptation of an existing technique of intrastromal corneal ring (ICRS) implantation enabling repositioning of the ring position postoperatively to manage a refractive failure in two patients with keratoconus. Methods. In two cases, KeraRing and Ferrara nomograms had suggested different ring positions. To manage with the differences between the two nomograms, a longer corneal tunnel was created followed by the classic intervention to move the ring through the initial intrastromal corneal tunnel according to the topographic values. Once the first ring position has failed, the ring segment was repositioned along the longer corneal tunnel according to the postoperative outcome. Results. Significant improvement in both cases was observed in the best corrected visual acuity (BCVA), uncorrected visual acuity (UCVA), and root mean square (RMS) measured with Scheimpflug imaging (Pentacam; Oculus GmBH, Wetzlar, Germany). The participants were followed for one year. Conclusion. In patients with keratoconus which exhibit significant differences between KeraRing and Ferrara nomograms, a longer tunnel should be created to enable repositioning of the ring postoperatively if necessary, to avoid extracting the ring or changing it.

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Zenlens scleral lenses for visual rehabilitation of patients with irregular cornea: a usage experience

Russian Ophthalmological Journal ◽

10.21516/2072-0076-2018-11-4-68-74 ◽

2018 ◽

Vol 11 (4) ◽

pp. 68-74 ◽

Cited By ~ 1

Author(s):

O. O. Alyaeva ◽

O. I. Ryabenko ◽

E. M. Tananakina ◽

I. S. Yushkova

Keyword(s):

Visual Acuity ◽

Social Significance ◽

Visual Rehabilitation ◽

Group 4 ◽

Average Improvement ◽

Uncorrected Visual Acuity ◽

Before And After ◽

Ring Segment ◽

Group 3 ◽

Group 2

Scleral lenses improve visual acuity in patients with irregular corneal astigmatism, which is especially important when other methods of correction are ineffective.Purpose: to assess the efficiency of Zenlens scleral lenses in patients with irregular cornea.Material and methods. A total of 120 patients (164 eyes) were examined, including 86 males and 34 females, aged from 13 to 63 years (mean age 35 ± 12 years). The patients were divided into 4 groups. Group 1 consisted of patients with keratoconus, group 2 — postpenetrating keratoplasty, group 3 — keratoconus after cross-linking and/or corneal ring segment implantation, while group 4 consisted of patients with other diseases. The efficiency criteria included visual acuity before and after scleral lens fitting and wearing time (hours per day). To determine social significance of scleral lens wearing, we selected 30 patients (46 eyes) with average best-corrected visual acuity (BCVA) before fitting 0.21 ± 0.08 (0.1–0.3).Results. Average uncorrected visual acuity before fitting did not exceed 0.2 and average visual acuity after fitting was 0.8 ± 0.15. Average improvement in visual acuity after fitting compared to uncorrected visual acuity was at least six lines in all groups and average improvement of visual acuity was approximately three lines compared to BCVA before fitting. 74.4 % and 19.5 % of patients demonstrated long-term (> 10 hours per day) and partial (8–10 hours per day) wear, respectively. Short-term wear (< 8 hours per day) was noted in 6.1 % of patients. Visual acuity of patients with low BCVA (mean 0.21 ± 0.08) increased by 0.57 (271.4 %).Conclusion. Scleral lenses can be successfully used for visual acuity improvement and social rehabilitation of patients with irregular cornea when other methods of correction are ineffective.

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