Characterization of the effect of intracorneal ring segment in corneal ectasia after laser refractive surgery

Peris-Martínez, Cristina; Bueno-Gimeno, Inmaculada; Alvarez-Arana, Izaskun; Piñero, David P.; Sampedro, Andrés Gené

doi:10.1177/1120672118808968

Cited by 6 publications

(5 citation statements)

References 31 publications

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“…Cristina Peris-Martínez et al 14 found statistically significant reduction of sphere (p = 0.043), a significant improvement of UCVA associated (p = 0.019) , a significant reduction of anterior corneal power measurements (p ⩽ 0.014) , steepest posterior keratometric reading (p = 0.006) were observed at 1 month postoperatively, with no significant changes afterwards (p ⩾ 0.133). No significant changes were observed in manifest cylinder (p ⩾ 0.175), BCVA (p ⩾ 0.174), flattest posterior keratometric measurement (p ⩾ 0.282), volumetric measurements (p ⩾ 0.051), and corneal biomechanical parameters (p ⩾ 0.068).…”

Section: Discussionmentioning

confidence: 93%

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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Section: Discussionmentioning

confidence: 93%

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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“…Differences in refractive behaviour across eyes and between individuals38 39 44 67 73 114 128 are of importance in analyses of dioptric power and the following briefly considers some methods towards qualitatively and quantitatively analysing anisometropia 44 67 73. Anisometropia and aniso-astigmatism are often a consequence of conditions such as keratoconus69 70 85 86 105 123 but can also be an important consideration in refractive42–44 74 87 125 or other surgeries42–44 87–113 sometimes involving IOL36 41–43 45 46 85 99–104 or other implants 89–92 105. Reliability and reproducibility of measures of refractive behaviour are integral to understanding anisometropia 40 57–64 66 109 120–123.…”

Section: Resultsmentioning

confidence: 99%

“… 44 67 73 Anisometropia and aniso-astigmatism are often a consequence of conditions such as keratoconus 69 70 85 86 105 123 but can also be an important consideration in refractive 42–44 74 87 125 or other surgeries 42–44 87–113 sometimes involving IOL 36 41–43 45 46 85 99–104 or other implants. 89–92 105 Reliability and reproducibility of measures of refractive behaviour are integral to understanding anisometropia. 40 57–64 66 109 120–123 Ocular accommodation, 21 22 28 30 31 54–58 62–68 70 73 127 outliers, departures from data normality, laterality and mirror symmetry 67 95 and reflection of cylinder axes 2 11–13 15 17 18 28 67 73 74 must be considered in effective analyses of anisometropia.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, effective analysis of corneal and lenticular power and power of the eye itself has become paramount. Corneal surgeries,85–95 including for pterygia88 and implants89–92 and their effects, with or without other forms of ophthalmic surgery such as LASIK81 83 or SMILE,95 have been studied using power vectors. The same applies to surgical treatment with IOL 96–109.…”

Section: A Brief Review Of Clinical Applications Using Effective Anal...mentioning

confidence: 99%

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Dioptric power and refractive behaviour: a review of methods and applications

2022

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Myopia is a global healthcare concern and effective analyses of dioptric power are important in evaluating potential treatments involving surgery, orthokeratology, drugs such as low-dose (0.05%) atropine and gene therapy. This paper considers issues of concern when analysing refractive state such as data normality, transformations, outliers and anisometropia. A brief review of methods for analysing and representing dioptric power is included but the emphasis is on the optimal approach to understanding refractive state (and its variation) in addressing pertinent clinical and research questions.Although there have been significant improvements in the analysis of refractive state, areas for critical consideration remain and the use of power matrices as opposed to power vectors is one such area. Another is effective identification of outliers in refractive data. The type of multivariate distribution present with samples of dioptric power is often not considered. Similarly, transformations of samples (of dioptric power) towards normality and the effects of such transformations are not thoroughly explored. These areas (outliers, normality and transformations) need further investigation for greater efficacy and proper inferences regarding refractive error. Although power vectors are better known, power matrices are accentuated herein due to potential advantages for statistical analyses of dioptric power such as greater simplicity, completeness, and improved facility for quantitative and graphical representation of refractive state.

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“…It should be considered that although ICRS implantation is safe, suboptimal results are still present in some cases, requiring adjustments and even the explantation of the ring segment [12][13] . Ferrara-type ring segments have been investigated during many years and demonstrated to be a safe option to manage corneal irregularities in a great variety of corneal conditions, including keratoconus [14][15][16][17][18][19][20][21][22][23][24] . It has been even confirmed the histological reversibility of the cornea when the ring segments are explanted [25] .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a new nomogram for Ferrara ring segment implantation in keratoconus

Fernández¹,

Peris-Martínez

Pérez-Rueda

et al. 2021

Int J Ophthalmol

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AIM: To evaluate the short-term clinical outcomes of Ferrara rings in keratoconus using an optimized nomogram developed after several years of research and retrospective analysis of clinical data. METHODS: This prospective longitudinal non-comparative clinical trial evaluated 88 eyes of 88 patients (age 18-62y) with keratoconus diagnosis from two Spanish centers. Ferrara ring segment (AJL Ophthalmic) implantation was performed in all cases, using the mechanical procedure in 25 eyes (28.4%) and a femtosecond laser-assisted procedure in 63 eyes (71.6%). The ring segments implanted in each case were selected using a new optimized nomogram that considered variables such as anterior corneal asphericity and astigmatism or the discrepancy among astigmatism and coma orientations. Visual, refractive, corneal topographic, aberrometric, and pachymetric changes after surgery were evaluated during a 3-month follow-up. RESULTS: The implants induced a significant refractive change as well as an improvement in uncorrected (UDVA) and corrected distance visual acuity (CDVA; P<0.001). Postoperative CDVA of 0.10 logMAR or better was achieved in 28.4% and 46.5% of eyes, respectively. Two eyes (2.3%) lost two or more lines of CDVA whereas a total of 53.5% of eyes gained lines of CDVA. A significant central anterior and posterior corneal flattening was induced (P≤0.003), with a significant reduction of anterior (P<0.001) and posterior corneal astigmatisms (P=0.048), and a change in anterior asphericity (P<0.001). Total primary coma (6 mm pupil) change was also statistically significant (preoperative 3.66±3.04 µm vs postoperative 2.33±2.26 µm, P<0.001). No significant differences were found in the effect of ring segments between cases implanted using the mechanical and femtosecond techniques (P≥0.101). CONCLUSION: The implantation of Ferrara rings based on the nomogram evaluated is safe and effective for promoting a visual rehabilitation in keratoconus, with a relevant control of primary coma aberration.

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Characterization of the effect of intracorneal ring segment in corneal ectasia after laser refractive surgery

Cited by 6 publications

References 31 publications

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

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

Dioptric power and refractive behaviour: a review of methods and applications

Evaluation of a new nomogram for Ferrara ring segment implantation in keratoconus

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