Changes in the total corneal refractive power after insertion of intrastromal rings in patients with keratoconus in short, medium and long term / Mudanças no poder refrativo total da córnea após a inserção de anéis intrastromais em pacientes com ceratocone a curto, médio e longo prazo

ABSTRACT Objective To analyze the short, medium and long-term efficacy and stability in 46 eyes with keratoconus, operated with Ferrara intrastromal corneal ring segments. Methods The primary endpoint was the mean keratometry of total corneal refractive power. We also studied the effects of age, degree of keratoconus and clinical phenotype on the results, as well as the following keratometry variations and aberrometry variations: flattest, most curved, mean, maximum, astigmatism, root mean square of primary coma aberration and root mean square of secondary coma aberration. Results The immediate postoperative reduction in mean keratometry of total corneal refractive power was 3.08±1.51 diopters (D) (p<0.001). At 4 years, the mean keratometry of total corneal refractive power increased to 0.57±0.96D (p=0.005). Between 4 and 7 years, there was no change in mean keratometry of total corneal refractive power (p=0.727). The degree of keratoconus was a factor affecting the efficacy of the intrastromal corneal ring segments, achieving a greater effect in those with a greater degree of keratoconus (p=0.012 between groups). The immediate postoperative reduction was 1.77±1.88D for the flattest, 3.91±2.30D for the most curved, 2.76±1.63D for the mean, 4.42±3.26D for the maximum, 2.15±2.68D for astigmatism, 1.03±0.83µm for root mean square of primary coma aberration and root mean square of secondary coma aberration (p<.001 in all cases). At 4 years, most curved increased by 0.42±0.78D (p=0.001), mean increased by 0.54±0.64 (p<0.001) and root mean square of primary coma aberration decreased 0.14±0.27µm (p=0.020). Conclusion Ferrara intrastromal corneal ring segment implantation is an effective and stable long-term treatment for patients with keratoconus. There is, however, partial regression in the medium term.

RESUMO Objetivo Analisar a eficácia e a estabilidade a curto, médio e longo prazo em 46 olhos com ceratocone, operados com segmentos de anel intrastromal corneano de Ferrara. Métodos A meta primária foi a ceratometria média de poder refrativo total da córnea. Também estudamos os efeitos da idade, grau de ceratocone e fenótipo clínico nos resultados, bem como as seguintes variações de ceratometria e variações de aberrometria: mais plana, mais curva, média, máxima, astigmatismo, raiz quadrada média da aberração comática primária e raiz quadrada média da aberração comática secundária. Resultados A redução pós-operatória imediata da ceratometria média do poder refrativo total da córnea foi de 3,08±1,51 dioptrias (D) (p<0,001). Aos 4 anos, a ceratometria média do poder refrativo total da córnea aumentou para 0,57±0,96D (p=0,005). Entre 4 e 7 anos, não houve mudança na ceratometria média da potência refrativa total da córnea (p=0,727). O grau de ceratocone foi um fator que afetou a eficácia dos segmentos do anel intrastromal da córnea, alcançando um efeito maior naqueles com maior grau de ceratocone (p=0,012 entre grupos). A redução pós-operatória imediata foi de 1,77±1,88D para a mais plana, 3,91±2,30D para a mais curva, 2,76±1,63D para a média, 4,42±3,26D para a máxima, 2,15±2,68D para o astigmatismo, 1,03±0,83µm para a raiz quadrada média da aberração comática primária e raiz quadrada média da aberração comática secundária (p<0,001 em todos os casos). Aos 4 anos, a maioria das curvas aumentou 0,42±0,78D (p=0,001), a média aumentou 0,54±0,64 (p<0,001) e a raiz quadrada média da aberração comática primária diminuiu 0,14±0,27µm (p=0,020). Conclusão O implante de anel intrastromal corneano Ferrara é um tratamento eficaz e estável a longo prazo para pacientes com ceratocone. Há, no entanto, uma regressão parcial a médio prazo.

Updates on managements for keratoconus / 国际眼科杂志(Guoji Yanke Zazhi)

@#A variety of therapeutic methods can be used to treat keratoconus. This article provides practical information for clinicians to make the most appropriate choices by reviewing the treatment of keratoconus. Search for keywords such as “keratoconus” “contact lenses” “corneal collagen cross-linking” “Intacs(corneal ring)” “keratoplasty” “gene therapy” “irregular astigmatism” through a database. According to the related literature, the treatment methods of keratoconus are reviewed. Glasses and contact lenses can be used for early keratoconus, while bowman layer transplantation, penetrating keratoplasty(PK), deep anterior lamellar keratoplasty(DALK), conductive keratoplasty and gene therapy can be used in advanced disease. In addition, cross-linking can prevent keratoconus progression, and intrastromal corneal ring segments(ICRS)reduce refractive error for therapeutic purposes by flattening the deformed cornea. In general, the development of ophthalmic diagnostic techniques and treatments can slow the progression of keratoconus, thereby reducing the need for corneal transplantation in patients with advanced keratoconus. Choosing the right keratoconus treatment can help patients with vision recover and prevent blindness.

Evaluation of clinical effectiveness of intrastromal corneal ring segments among keratoconus patients / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To evaluate the clinical effectiveness of intrastromal corneal ring segments among the patients suffering from keratoconus. <p>METHODS: A retrospective and comparative interventional design had been utilized on the basis of postoperative follow up among 56 keratoconus patients. Visual acuity was significantly assessed during complete ophthalmic examination of the patients. The femtosecond laser had been used to create the corneal tunnels in 15 eyes; whereas, the corneal tunnels were created in 72 eyes mechanically. <p>RESULTS: The ranges and standard deviations had been used to obtain results. It had been revealed through ophthalmic assessment that the mean preoperative uncorrected visual acuity observed was 1.38±0.37 Logarithm of Minimal Angle of Resolution. Moreover, a significant improvement was observed postoperatively in visual acuity by 0.58±0.32 during the fourth month. The improvement was also witnessed in the 16^th month by 0.48±0.30. <p>CONCLUSION: The implantation of intrastromal corneal ring segments is an efficient and effective surgical intervention for the treatment of keratoconus. Thus, identified intervention seems to be associated with appropriate visual outcomes and safety after the development of femtosecond as well as mechanical tunnels.

Evaluation of intrastromal corneal ring segments for treatment of keratoconus with a mechanical implantation technique.

Purpose: To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation in patients with keratoconus using a mechanical implantation technique. Materials and Methods: Thirty eyes of 17 patients with keratoconus were enrolled. ICRSs (Keraring) were implanted after dissection of the tunnel using Tunc's specially designed dissector under suction. A complete ophthalmic examination was performed, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent, keratometric readings, inferosuperior asymmetry index (ISAI), and ultrasound pachymetry. All 3-, 6-, and 12-month follow-ups were completed, and statistical analysis was performed. Results: The mean preoperative UDVA for all eyes was 1.36 ± 0.64 logMAR. At 12 months, the mean UDVA was 0.51 ± 0.28 logMAR (P = 0.001), and the mean preoperative CDVA was 0.57 ± 0.29 logMAR, which improved to 0.23 ± 0.18 (P = 0.001) at 1 year. There was a significant reduction in spherical equivalent refractive error from –6.42 ± 4.69 diopters (D) preoperatively to –1.26 ± 1.45 D (P = 0.001) at 1 year. In the same period, the mean K-readings improved from 49.38 ± 3.72 D to 44.43 ± 3.13 D (P = 0.001), and the mean ISAI improved from 7.92 ± 3.12 to 4.21 ± 1.96 (P = 0.003). No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during and or after surgery. Conclusion: ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for keratoconus. All parameters improved by the 1-year follow-up.

Evaluation of intrastromal corneal ring segments for treatment of post-LASIK ectasia patients with a mechanical implantation technique.

Aim: To evaluate the clinical outcomes of Keraring segment implantation in patients with post- laser-assisted in situ keratomileusis (LASIK) ectasia, using a mechanical implantation technique. Materials and Methods: Twelve eyes of 10 patients with post-LASIK ectasia were enrolled. Intracorneal ring segments (ICRS) were implanted after dissection of the tunnel using Tunc's specially designed dissector under suction. A complete ophthalmic examination was performed, including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical equivalent, keratometric (K) readings, inferosuperior asymmetry index (ISAI), and ultrasound pachymetry. All 3, 6, and 12-month follow-ups were completed, and statistical analysis was performed. Results: The mean preoperative UDVA for all eyes was 1.28 ± 0.59 logMAR. At 12 months, the mean UDVA was 0.36 ± 0.19 logarithm of the Minimum Angle of Resolution (logMAR) (P=0.002), and the mean preoperative CDVA was 0.58 ± 0.3 logMAR, which improved to 0.15 ± 0.12 (P=0.002) at 1 year. There was a significant reduction in cylindrical refractive and spherical equivalent refractive error from –5.29 ± 2.47 diopters (D) and –5.54 ± 5.04 D preoperatively to –1.47 ± 0.71 D and –0.74 ± 1.07 D (P=0.001, P=0.002), respectively, at 1 year. In the same period, the mean K- readings improved from 47.93 ± 4.84 D to 40.87 ± 2.36 D (P=0.002), and the mean ISAI improved from 5.34 ± 3.05 to 2.37 ± 1.68 (P=0.003). No significant changes in mean central corneal thickness were observed postoperatively. There were no major complications during or after surgery. Conclusion: ICRS implantation using a unique mechanical dissection technique is a safe and effective treatment for post-LASIK ectasia. All parameters showed improvement at 1-year follow-up.

Intrastromal Corneal Ring Segments (KeraRing(R)) Implantation for the Correction of Keratoconus

PURPOSE: To report the outcomes after the implantation of intrastromal corneal ring segments (KeraRing(R)) by manual tunnel creation for the correction of keratoconus. METHODS: The present retrospective case series was comprised of 12 eyes of 11 consecutive keratoconic patients. Intrastromal corneal ring segments (KeraRing(R)) were implanted for keratoconus correction after manual tunnel creation. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive outcome, and complete ophthalmologic examinations were performed before and after surgery at 1 day, 1 week, 3 months, and 6 months. Corneal topography was measured before surgery, 6 months after surgery and during any necessary follow-up visits. RESULTS: Intrastromal corneal ring segments (KeraRing(R)) implantation significantly increased BCVA from logMAR 0.47 +/- 0.19 to logMAR 0.28 +/- 0.17 (P < 0.05) and decreased the spherical equivalent from -6.03 +/- 3.24 D to -2.24 +/- 1.96 D. The simulated keratometric value in the Orbscan IIz significantly decreased in K maximum from 50.7 +/- 2.93D to 47.65 +/- 3.15 D and in K minimum from 47.65 +/- 3.15 D to 44.92 +/- 2.80 D. CONCLUSIONS: Intrastromal corneal ring segments implantation (KeraRing(R)) by manual tunnel creation appears to be effective in improving BCVA and reducing corneal astigmatism and keratometric value in keratoconic patients. KeraRing(R) may delay or prevent the need for a corneal graft, and reduce the contact lens intolerance.