The number of intracorneal ring segments in asymmetric and central cones

Utine, Canan Aslı; Özizmirliler, Denizcan; Kayabaşı, Mustafa; Günenç, Üzeyir

doi:10.1186/s40662-021-00234-6

Cited by 8 publications

(6 citation statements)

References 27 publications

(57 reference statements)

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“…There are various nomograms in practice for ICRS selection considering the tomographic pattern, refractive parameters, and corneal aberrations. [ 13 14 15 16 ] In our study, group of extreme steep cornea, however, almost half of patients could not obtain refractive parameters (sphere, cylinder, and spherical equivalent) with autorefractometer, which are used to be an important basis of ring selection. The present results suggest surgical planning based on mean asphericity, despite the small sample of patients, could still achieve favorable outcomes.…”

Section: Discussionmentioning

confidence: 66%

Outcomes of 320-degree intrastromal corneal ring segment implantation for advanced keratoconus

Chen,

Sun

2024

Taiwan Journal of Ophthalmology

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PURPOSE: The purpose of this study is to investigate visual and tomographic outcomes and complications of long-arc length intrastromal corneal ring segment (ICRS) implantation for the treatment of advanced keratoconus. MATERIALS AND METHODS: This retrospective study enrolled 10 eyes of 9 subjects. All patients received 320-degree ICRS (320-ICRS) implantation with femtosecond laser-assisted technique based on their advanced grading with preoperative high keratometry (K) value, asphericity (Q), and astigmatism. Medical records and corneal tomography changes of consecutive patients were reviewed at baseline, 1, and 3 months after treatment. RESULTS: There are 6 female and 3 male patients with a mean age of 29.6 ± 7.8 years in this study. Mean K (Km) reduced from 59.01 ± 5.81 D preoperatively to 50.7 ± 5.3 and 50.2 ± 3.66 postoperatively (after 1 month and 3 months respectively, P < 0.001). The changes in mean K, K1, K2, and maximum K (Kmax) reading were all statistically significant (all P < 0.001). Mean uncorrected distance visual acuity (UCVA) improved from 20/400 to 20/200. Mean best-corrected distance visual acuity (BCVA) improved from 20/100 to 20/60. Both UCVA and BCVA showed a trend of improvement at postoperative month 3, though insignificant in BCVA (P = 0.114). Mean Q improved from −1.59 ± 0.62 preoperatively to −0.48 ± 1.08 and −0.11 ± 1.04 postoperatively (after 1 month and 3 months respectively, P = 0.016, 0.002). No intraoperative or postoperative complications were observed. CONCLUSIONS: The present results suggest that implanting a 320-ICRS is a safe and effective procedure for treating patients with advanced keratoconus. Preoperative corneal measurements and the selection of types and thickness of ICRS are important to prevent unpredictable results.

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Section: Discussionmentioning

confidence: 66%

Outcomes of 320-degree intrastromal corneal ring segment implantation for advanced keratoconus

Chen,

Sun

2024

Taiwan Journal of Ophthalmology

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“…11 Canan A.et.al. 7,12 In a similar study on 42 keratoconic eyes , the UDVA and BCVA improved significantly and also found a significant reduction in refractive spherical equivalent , cylinder and SimK avg postoperatively (P<0.001). The mean postoperative Q changed from -1.06±0.48 to -0.57±0.58 (P<0.001).…”

Section: Discussionmentioning

confidence: 77%

Corneal asphericity changes after implantation of intracorneal ring segment (kerarings) in the treatment of Keratoconus

Mousa

2021

NILES journal for Geriatric and Gerontology

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Purpose: To evaluate changes in visual outcome, refractive error and corneal asphericity after implantation of intracorneal ring segments (ICRS) (keraring) for the treatment of keratoconus Setting: Memorial institute for ophthalmic research, Egypt Methods: This study was conducted on 23 eyes of 17 patients with keratoconus. ICRS was implanted intrastromally in the cornea as a treatment for keratoconus. One or two rings with thicknesses ranging from 150 µm to 300 µm and arc lengths ranging from 160 o to 210 o were implanted. Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA)and refractive error (sphere, cylinder)changes were assessed. Keratometric values (k1,K2,Kmax)and corneal asphericity values anterior and posterior respectively(Q ant and Q post ) were obtained from Pentacam . Results: There was clinically significant improvement regarding UCVA from 0.1±0.04 to 0.31±0.17 and improvement in BCVA was from 0.37±0.15 to 0.46±0.1. The spherical and cylindrical errors significantly decreased postoperatively (p<0.001). K2 showed a highly significant decrease (p =0.001) while K1 showed a significant reduction (p=0.022) and Kmax showed non-significant changes postoperatively with p=0.469.Q anterior shows significant decrease from -1.29±0.55 to -0.78±0.77 (p<0.001) while Q posterior shows non-significant change (p =0.692). Conclusion: ICRS implantation for the treatment of keratoconus changes the anterior corneal asphericity by approximating the Q value to the ideal Q value (-0.46) and improves the UCVA and BCVA of patients in addition to decreasing the refractive sphere and cylinder values.

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“…The number of rings used is still controversy inspite of various nomograms present 12 .Utine et al studied the number of rings in comparison of asymmetric and central cones, there results revealed that double ring implantation were superior to single ring as regard the corneal astigmatism, keratometry, and anterior corneal asphericity for central and partially asymmetrical however single ring was superior in totally asymmetrical cones 2 .…”

Section: Resultsmentioning

confidence: 99%

“…Intracorneal ring segments (ICRS) have long been used for visual and optical rehabilitation of ectatic corneal conditions either alone or accompanied with other treatment procedures. 1,2 In most cases it is well tolerated effective treatment with long term improvement of refractive and keratometry measurements 3 .However visual satisfaction is not guaranteed in some cases inspite of reaching close to emmetropia . 4 This visual satisfaction unpredictability is caused by the insufficiency of the lower order aberrations on which we build our choice of rings to explore the visual quality of the patients.…”

Section: Introductionmentioning

confidence: 99%

Corneal asphericity changes after implantation of single intracorneal corneal ring segment vs implantation of double intracorneal segments in the cornea for treatment of keratoconus

Mousa

2022

NILES journal for Geriatric and Gerontology

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Aim:To compare the effect of implantation of intracorneal rings on corneal sphericity between one segment ring and double segment ring implantation in keratoconus eyes. Setting: Memorial institute for ophthalmic research Methods: This study is retrospective study done on 30 eyes of keratoconus patients between 2019and 2021. Intracorneal rings were implanted in the cornea for treatment of keratoconus The study was done on two study groups, in Group A one ring segment was implanted and in Group B two ring segments were implanted. The choice of the number, thickness and arc length of the rings were done according to Kera ring manufacture nomogram. We studied the Corneal sphericity measured by corneal ashericity coefficient (Q value) concluded from Pentacam preoperative and 6month postoperative. Keratometric values, visual acuity and refraction of the patients were also studied preoperatively and 6month postoperative. Results:The changes in refraction were statistically significant before and after surgery in both groups regarding UCVA and refraction. Comparing both groups regarding sphere and cylinder refraction, we found that there was significant difference in sphere refraction pre and postoperatively (p<0.001& 0.009 respectively) and in cylinder refraction preoperatively (p =0.024). The changes in Q anterior were significant in both groups. Moreover, the changes in K1, K2, K max and astigmatism values before and after ring implantation were significant in both groups. Comparing the results of K1, K2, K max and Q anterior significant difference was observed between the two groups after surgery while there was significant difference in K1and K2 before surgery. Conclusion: Intracorneal ring segments implantation for treatment of keratoconus either one or two rings change the anterior corneal asphericity approximating the Q anterior value to the ideal Q value (-0.46) and improve the UCVA and the BCVA of patients besides decrease the refractive sphere and cylinder values. Implantation of two rings have higher effect than implantation of one ring on approximating the Q anterior value to ideal.

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The number of intracorneal ring segments in asymmetric and central cones

Cited by 8 publications

References 27 publications

Outcomes of 320-degree intrastromal corneal ring segment implantation for advanced keratoconus

Outcomes of 320-degree intrastromal corneal ring segment implantation for advanced keratoconus

Corneal asphericity changes after implantation of intracorneal ring segment (kerarings) in the treatment of Keratoconus

Corneal asphericity changes after implantation of single intracorneal corneal ring segment vs implantation of double intracorneal segments in the cornea for treatment of keratoconus

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