ABSTRACT
PURPOSE: To evaluate the clinical outcomes after implantation of a new 320°-arc length Ferrara intrastromal corneal ring segment (320-ICRS) in eyes of patients with keratoconus. METHODS: A multicentric nonrandomized study was conducted in which a new 320-ICRS was placed in 138 eyes of 130 patients with keratoconus. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), keratometry, corneal volume, asphericity, lines of vision gain/loss, and vectorial analysis were assessed preoperatively and at the final follow-up visit after the procedure. RESULTS: The mean follow-up time was 6.2 ± 3.3 (SD) months (range 3-12 months). Mean UDVA improved from 20/250 to 20/60. Mean CDVA improved from 20/100 to 20/40. Mean Q improved from -1.12 ± 0.49 preoperatively to -0.28 ± 0.51 postoperatively (P < 0.001). Mean corneal volume increased from 56.2 ± 4.28 mm preoperatively to 57.6 ± 4.74 postoperatively (P < 0.001). Mean Km reduced from 53.3 ± 5.5 D preoperatively to 47.8 ± 4.6 D postoperatively (P < 0.001). The change in UDVA, CDVA, and topographic astigmatism was statistically significant (P < 0.0001). CONCLUSIONS: The 320-ICRS can efficiently and safely improve visual acuity in keratoconus, modifying the corneal shape to a more physiologic, aspheric shape.
Subject(s)
Corneal Stroma/surgery , Keratoconus/surgery , Prostheses and Implants , Adolescent , Adult , Child , Female , Follow-Up Studies , Humans , Keratoconus/physiopathology , Lasers, Excimer/therapeutic use , Male , Middle Aged , Prosthesis Implantation , Refraction, Ocular/physiology , Visual Acuity/physiology , Young AdultABSTRACT
PURPOSE: To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery. METHODS: Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK). RESULTS: The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative complications were observed. CONCLUSION: ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.
Subject(s)
Corneal Diseases/surgery , Keratoconus/etiology , Keratoconus/surgery , Keratomileusis, Laser In Situ/adverse effects , Photorefractive Keratectomy/adverse effects , Prosthesis Implantation , Adult , Corneal Diseases/etiology , Corneal Diseases/physiopathology , Corneal Stroma/surgery , Corneal Topography , Female , Humans , Male , Middle Aged , Prostheses and Implants , Refraction, Ocular/physiology , Retrospective Studies , Treatment Outcome , Visual Acuity/physiology , Young AdultABSTRACT
ABSTRACTPurpose:To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery.Methods:Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK).Results:The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative complications were observed.Conclusion:ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.
RESUMOObjetivo:Avaliar os resultados do implante de anel intraestromal de córnea para correção de ectasia pós-cirurgia refrativa.Métodos:Quarenta e um olhos de 25 pacientes, 13 homens e 12 mulheres, com ectasia pós-cirurgia refrativa (PRK ou LASIK) foram incluídos em um estudo não randomizado, retrospectivo e observacional. A média de idade no momento do implante do anel é de 28,66 anos. Em todos os olhos, o túnel corneano foi criado através da dissecção mecânica da córnea. Os resultados avaliaram acuidade visual sem correção (AVSC) e acuidade visual com correção (AVCC), refração, ceratometria e topografia corneana computadorizada. Os pacientes foram divididos em dois grupos de acordo com a cirurgia refrativa. Grupo A: PRK, Grupo B: LASIK.Resultados:A média do astigmatismo pré-operatório foi reduzida de -1,88 D para -0,84 D no grupo A (P=0,096) e de -3,18 D para -1,77 D no grupo B (P=0,000). A média do astigmatismo ceratométrico foi reduzida de -2,58 D para -1,66 D no grupo A (P=0,010) e de -4,80 para -2,78 D no grupo B (P=0,000). A média do componente esférico foi reduzida de -2,97 D para -2,05 D no grupo A (P=0,065) e de -3,31 D para -2,42 D no grupo B (P=0,014). Nenhuma diferença estatisticamente significativa foi observada entre os grupos, quando se comparou os resultados do pré e pós-operatório. Não ocorreram complicações intra ou pós-operatórias.Conclusão:O implante de anel intraestromal de córnea é uma boa opção para o tratamento de ectasia pós-cirurgia refrativa, tendo resultado na redução significativa do astigmatismo refracional e melhora da acuidade visual com correção.
