Donut-shaped Corneal Allogeneic Intrastromal Segment as an Alternative to Deep Anterior Lamellar Keratoplasty in Advanced Keratoconus.

PURPOSE: The aim of this study was to describe a new technique of selective corneal stromal transplantation for keratoconus treatment, donut-shaped CAIRS (corneal allogeneic intrastromal ring segment). METHODS: A donut-shaped corneal graft is obtained using a double-bladed trephine. Descemet membrane, endothelium, and epithelium are all removed from the graft. Only stromal tissue is transplanted. A wide 360-degree intrastromal tunnel is created using the femtosecond laser, with a 30-degree angulation. The diameter is from 5.4 mm to 8 mm optical zone. After dehydration, the corneal graft is inserted into the tunnel. We report the clinical and tomographic outcomes after the procedure in 3 patients. RESULTS: The mean follow-up time after donut-shaped CAIRS was 6.01 ± 1.02 months. In case 1, best spectacle-corrected visual acuity improved from 20/150 to 20/40. In case 2, it improved from 20/400 to 20/40, and in case 3 from 20/200 to 20/40. The mean preoperative K was 57.3 ± 4.5 D and reduced to 44.2 ± 2.5 D after donut-shaped CAIRS. The mean spherical equivalent decreased from -9.8 ± 3.2 preoperatively to -3.2 ± 2.2 postoperatively. No intraoperative or postoperative complications were observed. Anterior segment OCT showed a mid-stroma implant, fusiform in shape, equidistant from the epithelium and endothelium. CONCLUSIONS: Donut-shaped CAIRS is a variation of the traditional CAIRS technique and showed to be an alternative option for keratoconus treatment, especially in moderate to advanced cases with a central clear cornea without scars. The technique is minimally invasive, and the visual axis remains untouched.

Preliminary results of a new intrastromal corneal ring segment as a tissue saving procedure in photorefractive keratectomy to correct moderate to high myopia.

AIM: To evaluate the clinical results after implantation of a new intrastromal corneal ring segment (ICRS) associated with photorefractive keratectomy (PRK) to correct high myopia (HM) patients with thin corneas. METHODS: We evaluated 42 eyes of 23 HM patients that had ICRS implantation followed by PRK. The mean age of patients was 29.1±7.12y (range 18 to 40 years old). Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), keratometry, spherical equivalent, pachymetry, and aberrometry were compared using ANOVA with repeated measurements evaluated preoperatively and at last follow-up visit after the procedures. The refractive predictability and simulated/real corneal ablation were also assessed. RESULTS: The mean follow-up time after PRK was 6.8±1.6mo. The mean preoperative UCVA improved from 20/800 preoperative to 20/100 after ICRS and 20/35 after PRK. The mean preoperative BCVA was 20/25 (range from 20/30 to 20/20) and remained unchanged after ICRS implantation. Following the PRK the mean BCVA was 20/25 (range from 20/30 to 20/20). The mean spherical equivalent decreased from -7.25±1.12 (range -5.00 to -9.00) preoperatively to -3.32±1.0 (range -2.00 to -5.00) postoperatively (P<0.001) after ICRS implantation and decreased from -2.44±1.51 preoperatively to 0.32±0.45 (range -0.625 to 0.875) postoperatively (P<0.001) after PRK. The change in BCVA and topographic astigmatism was statistically significant (P<0.0001). CONCLUSION: ICRS in HM associated with PRK can be a tissue saving procedure and an alternative surgical option for correction of moderate to high myopia.

Clinical Outcomes After Implantation of 320°-Arc Length Intrastromal Corneal Ring Segments in Keratoconus.

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.

Intrastromal Corneal Ring Segments for Astigmatism Correction after Deep Anterior Lamellar Keratoplasty.

Background. To evaluate the change in corneal astigmatism after intrastromal corneal ring segment (ICRS) implantation in keratoconus patients with previous deep anterior lamellar keratoplasty (DALK). Design was a longitudinal, retrospective, interventional study. The study included 25 eyes of 24 patients with keratoconus who had DALK performed at least two years prior to ICRS implantation. All patients had a clear corneal graft with up to 8.00 D of corneal astigmatism and intolerance to contact lenses. The studied parameters were age, sex, corrected distance visual acuity (CDVA), maximum keratometry (K1), minimum keratometry (K2), spherical equivalent, and astigmatism. There was a statistically significant decrease in the postintervention analysis as follows: 3.5 D reduction in K1 (p < 0.001); 1.53 D in K2 (p = 0.005); and 2.52 D (p < 0.001) in the average K. The spherical equivalent reduced from -3.67 D (±2.74) to -0.71 D (±2.35) (p < 0.001). The topographic astigmatism reduced from 3.87 D preoperatively to 1.90 D postoperatively (p < 0.001). The CDVA improved from 0.33 (±0.10) to 0.20 (±0.09, p < 0.001). ICRS implantation is a useful option for the correction of astigmatism after DALK as it yields significant visual, topographic, and refractive results.

Intrastromal corneal ring segment implantation to correct astigmatism after penetrating keratoplasty.

PURPOSE: To evaluate the clinical outcomes of implantation of Ferrara intrastromal corneal ring segments (ICRS) in patients with astigmatism after penetrating keratoplasty (PKP). SETTING: Private clinic, Belo Horizonte, Brazil. DESIGN: Retrospective consecutive case series. METHODS: Chart records of post-PKP patients who had ICRS implantation from May 2005 to September 2009 were retrospectively reviewed. The following parameters were studied: corrected distance visual acuity (CDVA), keratometry (K) values, spherical equivalent (SE), spherical refractive error, corneal topographic astigmatism, minimum K, and maximum K. RESULTS: The study evaluated 59 eyes (54 patients). The mean CDVA (logMAR) improved from 0.45 ± 0.17 (SD) (range 0.18 to 1.00) to 0.30 ± 0.17 (range 0.00 to 1.00). The mean SE was -6.34 ± 3.40 diopters (D) (range 0.37 to -16.50 D) preoperatively and -2.66 ± 2.52 D (range 0.87 to -10.50 D) postoperatively. The mean spherical refractive error decreased from -7.10 ± 3.07 D (range 2.15 to 16.68 D) preoperatively to -3.46 ± 2.05 D (range 0.88 to 10.79 D) postoperatively. No patient lost visual acuity. The mean corneal topographic astigmatism decreased from 3.37 ± 1.51 D preoperatively to 1.69 ± 1.04 D postoperatively. The mean maximum K value decreased from 48.09 ± 2.56 D to 44.17 ± 2.67 D and the mean minimum K value, from 44.90 ± 2.54 D to 42.46 ± 2.63 D. All changes were statistically significant (P<.0001). CONCLUSION: Intrastromal corneal ring segments effectively reduced corneal cylinder in patients with astigmatism after PKP.

[Deep lamellar keratectomy using the big-bubble technique in patients with keratoconus]. / Ceratectomia lamelar anterior profunda usando a técnica "big-bubble" em pacientes com ceratocone.

PURPOSE: To evaluate patients with keratoconus 12 months after deep anterior lamellar keratectomy using the big-bubble technique. METHODS: A retrospective study of 79 consecutive eyes of 71 patients with moderate to severe keratoconus with visual impairment after optical correction and intolerant to contact lens fitting. All transplants were performed by the same experienced surgeon, from January 2007 to February 2009 using the technique of deep anterior lamellar keratectomy by big-bubble. Data analyzed were gender, age, corneal pachymetry, endothelial cell density, dynamic astigmatism and best correct visual acuity after keratectomy. RESULTS: Mean age was 30,4 (± 10.2) years, 39 (54,9%) were female and 32 (45,1%) male. The ultrasonic pachymetry average was 518.6 (± 29.5) µm. Seventy-two (91.1%) had a best dynamic corrected visual acuity better or equal to 20/50. Mean dynamic astigmatism was - 3.5 (± 1.5) spherical diopters. The mean endothelial cell density found according to age distribution had patients between 11-20 years with 3,053 (± 532) cel/mm(2); 21-30 years with 2,674 (± 25) cel/mm(2); 31-40 years with 2,737 (± 575) cel/mm(2); 41-50 years with 2,585 (± 476) cel/mm(2) and 51-60 years with 2,398 (± 667) cel/mm(2). Microperfurations had incidence of 8,8%. CONCLUSION: The deep anterior lamellar keratectomy using the big-bubble technique is a valuable treatment for patients with keratoconus, reaching a final best correct visual acuity similar to penetrating keratoplasty. The mean endothelial cell count is within the normal range for age after the procedure. No rejection or corneal edema were noted after all points' removal. The dynamic astigmatism in deep anterior lamellar keratectomy is similar to that found in reports of penetrating keratoplasties. Deep anterior lamellar keratectomy using the big-bubble technique must be studied as the first option for the treatment of keratoconus.

Ceratectomia lamelar anterior profunda usando a técnica "big-bubble" em pacientes com ceratocone / Deep lamellar keratectomy using the big-bubble technique in patients with keratoconus

OBJETIVOS: Avaliar através de um estudo retrospectivo pacientes com ceratocone, a partir do 12º mês após a ceratectomia lamelar anterior profunda usando a técnica "big-bubble". MÉTODOS: Estudo retrospectivo de consecutivos 79 olhos de 71 pacientes com ceratocone moderado a grave, com baixa acuidade visual após as correções ópticas e intolerantes à adaptação de lente de contato. Todos os transplantes foram realizados pelo mesmo experiente cirurgião, no período de janeiro de 2007 a fevereiro de 2009, utilizando a técnica de ceratectomia lamelar anterior profunda pelo "big-bubble". Os dados analisados foram sexo, idade, paquimetria corneana, densidade endotelial, astigmatismo dinâmico e melhor acuidade visual corrigida (BCVA) após a ceratectomia. RESULTADOS: A idade média verificada foi de 30,4 (± 10,2) anos, com 39 (54,9%) do sexo feminino e 32 (45,1%) do masculino. A paquimetria ultrassônica média foi de 518,6 (± 29,5) μm. Setenta e dois (91,1%) dos transplantes realizados obtiveram acuidade visual dinâmica corrigida melhor ou igual a 20/50. A média do astigmatismo dinâmico foi de - 3,5 (± 1,5) dioptrias cilíndricas. A média da densidade endotelial encontrada conforme a faixa etária teve a distribuição com os pacientes de 11 a 20 anos com 3.053 (± 532) cél/mm²; 21 a 30 anos com 2.674 (± 725) cél/mm²; 31 a 40 anos com 2.737 (± 575) cél/mm²; 41 a 50 anos com 2.585 (± 476) cél/mm² e 51 a 60 anos com 2.398 (± 667) cél/mm². Microperfuração no per-operatório teve uma incidência de 8,8%. CONCLUSÃO: A ceratectomia lamelar anterior profunda pela técnica "big-bubble" é um valioso tratamento para pacientes com ceratocone, alcançando uma melhor acuidade visual corrigida final semelhante ao transplante penetrante. A contagem média de células endoteliais apresenta-se dentro da normalidade para a faixa etária após o procedimento. Não foram encontradas córneas rejeitadas ou com edema após a retirada de todos os pontos. O astigmatismo dinâmico na ceratectomia lamelar anterior profunda é similar aos encontrados nos relatos de ceratoplastias penetrantes. A ceratectomia lamelar anterior profunda pela técnica do "big-bubble" deve ser estudada como primeira opção para o tratamento do ceratocone.

PURPOSE: To evaluate patients with keratoconus 12 months after deep anterior lamellar keratectomy using the big-bubble technique. METHODS: A retrospective study of 79 consecutive eyes of 71 patients with moderate to severe keratoconus with visual impairment after optical correction and intolerant to contact lens fitting. All transplants were performed by the same experienced surgeon, from January 2007 to February 2009 using the technique of deep anterior lamellar keratectomy by big-bubble. Data analyzed were gender, age, corneal pachymetry, endothelial cell density, dynamic astigmatism and best correct visual acuity after keratectomy. RESULTS: Mean age was 30,4 (± 10.2) years, 39 (54,9%) were female and 32 (45,1%) male. The ultrasonic pachymetry average was 518.6 (± 29.5) μm. Seventy-two (91.1%) had a best dynamic corrected visual acuity better or equal to 20/50. Mean dynamic astigmatism was - 3.5 (± 1.5) spherical diopters. The mean endothelial cell density found according to age distribution had patients between 11-20 years with 3,053 (± 532) cel/mm²; 21-30 years with 2,674 (± 25) cel/mm²; 31-40 years with 2,737 (± 575) cel/mm²; 41-50 years with 2,585 (± 476) cel/mm² and 51-60 years with 2,398 (± 667) cel/mm². Microperfurations had incidence of 8,8%. CONCLUSION: The deep anterior lamellar keratectomy using the big-bubble technique is a valuable treatment for patients with keratoconus, reaching a final best correct visual acuity similar to penetrating keratoplasty. The mean endothelial cell count is within the normal range for age after the procedure. No rejection or corneal edema were noted after all points' removal. The dynamic astigmatism in deep anterior lamellar keratectomy is similar to that found in reports of penetrating keratoplasties. Deep anterior lamellar keratectomy using the big-bubble technique must be studied as the first option for the treatment of keratoconus.

Delaminação límbica: uma nova técnica para correção de astigmatismo pós-transplante / Limbal delamination: a new technique for post-transplantation astigmatism correction

Objetivo: Avaliar segurança e eficácia da técnica de delaminação límbica para correção de astigmatismos pós-transplantes. Métodos: Cinco pacientes, sendo três do sexo feminino e dois do sexo masculino com idades entre 21 e 42 anos, apresentando erros de refração e enxerto transparente após transplante penetrante, foram submetidos à delaminação límbica. Resultados: Em um ano de acompanhamento, os enxertos permaneceram transparentes e o astigmatismo foi reduzido em média de 3,80 dioptrias cilíndricas. Conclusão: A delaminação límbica mostrou-se técnica eficiente para correção dos astigmatismos pós-transplante.