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

Mousa, Rasha

doi:10.21608/niles.2021.205502

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…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. 5 As the corneal asphericity of the cornea is the main source of eye spherical aberrations so The corneal asphericity coefficient (i.e., Q value) should be evaluated in association of keratometric values for better assessment of the effect on visual quality 5 .Various nomograms are used as clinical guidelines depending on preoperative clinical and topographic data to determine the number, size , arc length and location of ring insertion 6 .However most of them are empirical and based on personal and clinical experiences 7 .Improvment of the current nomograms to improve predictability of refractive and visual outcome needs a lot of effort and clinical feedback is important for this to be achieved 8 .…”

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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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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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Corneal densitometry changes in keratoconus patients after intrastromal corneal ring segments implantation

Basiony,

Mohammad Abdulfattah,

Ibrahim

2024

Journal of the Egyptian Ophthalmological Society

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Background Keratoconus (KC) is an ectatic corneal disorder characterized by progressive corneal thinning with myopic astigmatism. Intrastromal corneal ring segments (ICRS) have been broadly selected as a surgical intervention for KC correction to delay the need of keratoplasty. The purpose of this study was to evaluate the corneal densitometry changes in the various annuluses and depths in KC corneas after intrastromal corneal ring segment (ICRS) implantation and to correlate those changes with the other optical and refractive outcomes. Methodology This was a prospective interventional study included 56 eyes of 40 patients with KC who underwent femtosecond laser-assisted Keraring ICRS implantation. The uncorrected and best-corrected visual acuities (UCVA and BCVA), refraction, keratometry, Q-value, thinnest corneal location thickness (TCLT), and corneal densitometry in all the annular zones were assessed preoperatively and 90 days after surgery. Results Following the ICRS implantation after 3 months, when compared to preoperatively, the UCVA, BCVA, improved significantly from 0.21±0.12 and 0.44±0.15 to 0.27±0.12 and 0.58±0.15 (P<0.001) and spherical equivalent (SE) decreased significantly, from −5.28±1.65 D to −4.05±1.24 D (P<0.001) whereas the K1, K2, Km, Kmax, reduced significantly from 47.67±4.10 D, 51.39±4.74 D, 49.44±4.28 D, and 57.78±7.35 D, to 44.28±2.86 D, 46.84±3.42 D, 45.45±2.98 D, and 53.89±5.49 D (P<0.001) respectively. Corneal astigmatism, and Q-value were markedly improved from 3.73±2.17 D and −0.99±0.5 to 2.55±2.08 and −0.28±0.5 (P<0.001) .As regard corneal densitometry there was a significant elevation in the mean density of 2–6 mm annulus for the anterior and posterior layers (P=0.001), of 2–6 mm and 6–10 mm annuluses and total diameter for the central layer (P<0.001, P=0.047, and P<0.001, respectively), and of 2–6 mm annulus and total diameter for the total corneal thickness (P<0.001 and P=0.014, respectively). In contrast, a significant decline in the densitometry readings was observed in the 10–12 annulus for the central, posterior, and total corneal layers (P=0.003, P<0.001, and P=0.008, respectively). The percentage changes in the corneal densitometry readings did not significantly correlate with the percentage changes in the UCVA, BCVA, SE, CA and Q value. The percentage changes in the central and total 2–6 mm annuluses densities correlated negatively with the percentage changes in the K1 (r=−0.30, P=0.025 and r=−0.29, P=0.029, respectively), K2 (r=−0.33, P=0.013 and r=−0.31, P=0.021, respectively), and Km (r=−0.34, P=0.010 and r=−0.33, P=0.014, respectively). Conclusions The ICRS implantation results in significant changes in corneal densitometry specifically in the central corneal layer and in the 2–6 mm annulus, with an inverse correlation with keratometric values of the front corneal surface. Besides, ICRS leads to substantial improvements of refractive status, visual acuity and corneal keratometry and asphericity.

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

Cited by 2 publications

References 8 publications

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

Corneal densitometry changes in keratoconus patients after intrastromal corneal ring segments implantation

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