Manually prepared lamellae for Descemet stripping endothelial keratoplasty (Pachy-DSEK): comparison of four dissection depths / Lamelas manualmente dissecadas para transplante endotelial de córnea (Pachy-DSEK): comparação entre quatro profundidades de dissecção

ABSTRACT Purpose: This study aimed to compare four depths of manual dissection for the preparation of Descemet stripping endothelial keratoplasty lamellae. Methods: Eye bank corneas were randomized into four groups according to dissection depths: Pachy-100 (incision depth = central corneal thickness-safety margin of 100 µm), Pachy-50 (safety margin of 50 µm), Pachy-0 (no safety margin), and Pachy+50 (incision depth = central corneal thickness + 50 µm). All endothelial lamellae were prepared using a standardized method of manual dissection (Pachy-DSEK). The central, paracentral (3.0-mm zone), and peripheral (6.0-mm zone) lamella thicknesses and incision depths were measured by optical coherence tomography. The 3.0-mm and 6.0-mm zone central-to-peripheral thickness ratios were calculated. Results: Endothelial perforation occurred only in the Pachy+50 group (n=3, 30%). Central lamella's thickness in Pachy-100, Pachy-50, Pachy-0, and Pachy+50 groups measured 185 ± 42 µm, 122 ± 29 µm, 114 ± 29 µm, and 58 ± 31 µm, respectively (p<0.001). The overall 3.0- and 6.0-mm C/P ratios were 0.97 ± 0.06 and 0.92 ± 0.14, respectively. Preoperative donor characteristics were not correlated with most thickness outcomes. The planned incision depth correlated significantly with most lamella's thickness parameters (p<0.001). The overall thickness of the lamella negatively correlated with the planned incision depth (p<0.001, r=-0.580). The best outcome was found in the Pachy-0 group, as 75% of the lamellae measured <130 µm and there was no endothelial perforation. Conclusions: By using a standardized method of dissection, most manually prepared lamellae presented a planar shape. Setting the incision depth to the central corneal thickness did not result in endothelial perforation and a high percentage of ultrathin lamellae was achieved.

RESUMO Objetivo: Comparar quatro profundidades de dissecção manual usadas no preparo de lamelas para transplante endotelial. Métodos: Córneas humanas de treinamento disponibilizadas foram randomizadas em quatro grupos: Pachy-100 (profundidade de incisão = espessura corneana central - margem de segurança de 100 µm), Pachy-50 (margem de segurança de 50 µm), Pachy-0 (sem margem de segurança) e Pachy+50 (profundidade de incisão = espessura corneana central + 50 µm). Todas as lamelas foram dissecadas através um método padronizado e já publicado (Pachy-DSEK). As espessuras das lamelas (centro, zona de 3,0mm e zona de 6,0mm) foram medidas com tomografia de coerência óptica. A razão de espessura centro-periferia foi calculada aos 3,0 e 6,0 mm de diâmetro. Resultados: Perfuração endotelial ocorreu apenas no grupo Pachy+50 (n=3, 30%). A espessura central da lamela nos grupos Pachy-100, Pachy-50, Pachy-0 e Pachy+50 foi de 185 ± 42 µm, 122 ± 29 µm, 114 ± 29 µm, e 58 ± 31 µm, respectivamente (p<0,001). As razões C/P aos 3,0 e 6,0 mm foram de 0,97 ± 0,06 e 0,92 ± 0,14, respectivamente. Os parâmetros de características do doador não se correlacionaram com os resultados de espessura de lamela. A profundidade planejada de incisão se correlacionou com a maioria dos parâmetros de espessura de lamela (p<0,001). A espessura de lamela se correlacionou negativamente com a profundidade planejada da incisão (p<0.001, r=-0,580). O melhor resultado foi observado no grupo Pachy-0, em que 75% das lamelas mediram abaixo de 130 µm e não houve perfuração endotelial. Conclusão: Através de um método padronizado de dissecção, a maioria das lamelas endoteliais apresentou uma configuração planar. O planejamento de profundidade de incisão igual à espessura corneana central resultou em alta porcentagem de lamelas ultrafinas sem ocorrência de perfuração.

Manually prepared lamellae for Descemet stripping endothelial keratoplasty (Pachy-DSEK): comparison of four dissection depths.

PURPOSE: This study aimed to compare four depths of manual dissection for the preparation of Descemet stripping endothelial keratoplasty lamellae. METHODS: Eye bank corneas were randomized into four groups according to dissection depths: Pachy-100 (incision depth = central corneal thickness-safety margin of 100 µm), Pachy-50 (safety margin of 50 µm), Pachy-0 (no safety margin), and Pachy+50 (incision depth = central corneal thickness + 50 µm). All endothelial lamellae were prepared using a standardized method of manual dissection (Pachy-DSEK). The central, paracentral (3.0-mm zone), and peripheral (6.0-mm zone) lamella thicknesses and incision depths were measured by optical coherence tomography. The 3.0-mm and 6.0-mm zone central-to-peripheral thickness ratios were calculated. RESULTS: Endothelial perforation occurred only in the Pachy+50 group (n=3, 30%). Central lamella's thickness in Pachy-100, Pachy-50, Pachy-0, and Pachy+50 groups measured 185 ± 42 µm, 122 ± 29 µm, 114 ± 29 µm, and 58 ± 31 µm, respectively (p<0.001). The overall 3.0- and 6.0-mm C/P ratios were 0.97 ± 0.06 and 0.92 ± 0.14, respectively. Preoperative donor characteristics were not correlated with most thickness outcomes. The planned incision depth correlated significantly with most lamella's thickness parameters (p<0.001). The overall thickness of the lamella negatively correlated with the planned incision depth (p<0.001, r=-0.580). The best outcome was found in the Pachy-0 group, as 75% of the lamellae measured <130 µm and there was no endothelial perforation. CONCLUSIONS: By using a standardized method of dissection, most manually prepared lamellae presented a planar shape. Setting the incision depth to the central corneal thickness did not result in endothelial perforation and a high percentage of ultrathin lamellae was achieved.

Intrastromal corneal ring segments followed by PRK for postkeratoplasty high astigmatism: prospective study.

PURPOSE: To evaluate refractive and topographic results of the association of intrastromal corneal ring segments (ICRS) with photorefractive keratectomy (PRK) for the correction of high (>6.0 diopters [D]) postkeratoplasty astigmatism (PKA). SETTING: University of São Paulo, São Paulo, Brazil. DESIGN: Prospective interventional study. METHODS: Postpenetrating keratoplasty patients, intolerant to contact lens fitting, and with corneal astigmatism higher than 6.0 D were treated by the combination of ICRS and PRK from January 2017 to June 2019. First, patients underwent femtosecond laser-assisted ICRS implantation to reduce and regularize corneal astigmatism, and 3 months later, submitted to PRK for the residual astigmatism. Outcomes were obtained 12 months after PRK. RESULTS: The study comprised 30 eyes of 29 patients. Mean uncorrected distance visual acuity (logMAR) changed from 1.16 ± 0.37 in the preoperative to 0.69 ± 0.40 after ICRS ( P < .0001) and to 0.34 ± 0.29 12 months after PRK ( P < .0001). Mean spherical equivalent decreased from -5.19 ± 4.81 D in the preoperative to -3.38 ± 4.51 D after ICRS ( P < .0001) and to -2.30 ± 2.84 D after PRK ( P = .132). Mean topographic astigmatism decreased from 7.88 ± 2.13 D in the preoperative to 5.47 ± 2.29 D after ICRS ( P < .0001) and to 4.12 ± 2.93 D after PRK ( P = .003). Mean refractive astigmatism decreased from 7.10 ± 1.13 D in the preoperative to 4.61 ± 1.61 D after ICRS ( P < .0001) and to 2.58 ± 1.49 D after PRK ( P < .0001). After PRK, the mean correction index (CI) for corneal astigmatism was 0.77 ± 0.36. The ICRS/PRK combination resulted in a higher CI than ICRS only, both for corneal and refractive astigmatism. 2 eyes (8%) presented clinically significant opacification. Other complications were endothelial rejection (n = 1, 4%), infectious keratitis (n = 1, 4%), and ICRS extrusion after corneal melting (n = 1, 4%). CONCLUSIONS: The association of ICRS and PRK was effective for treating high PKA. This strategy improved visual acuity, spherical equivalent, topographic and refractive astigmatism and resulted in a high CI. Safety questions remain open and must be balanced against benefits.

Standardized pachymetry-assisted manual lamellar dissection for Descemet stripping endothelial keratoplasty.

PURPOSE: To present an alternative technique (Pachy-DSEK) for the manual preparation of thin endothelial lamellae in Descemet stripping endothelial keratoplasty (DSEK), as well as to evaluate its visual and anatomic outcomes. METHODS: A retrospective chart review was conducted in 15 cases who underwent DSEK at a private eye clinic in Brazil (INOB, Brasília) from June 2017 to December 2019. All patients had ocular comorbidities and relative contraindications to Descemet membrane endothelial keratoplasty (DMEK). All endothelial lamellae were manually prepared by using a standardized technique. Best corrected visual acuity (BCVA), tomographic parameters and graft's thickness were evaluated preoperatively and at 6 months. Endothelial cell counts were evaluated preoperatively and at 12 to 24 months. RESULTS: During preparation there was one case (6%) of peripheral tear and no tissue was lost. At 6 months, the median BCVA improved from 1.60 to 0.40 logMAR (p = 0.0009). There was no significant change in anterior (p = 0.507) and posterior astigmatism (p = 0.483), anterior (p = 0.683) and posterior mean keratometry (p = 0.767), and total corneal power (p = 0.952). The median central graft thickness at 6 months was 80 µm. Ultrathin grafts (<130 µm) were achieved in 80% of cases. At 12 to 24 months endothelial cell count decreased significantly. Graft's detachment occurred in two cases (13%) and endothelial rejection in one case (6%). CONCLUSION: By using ultrasonic pachymetry intra-operatively and standardizing graft preparation, most manually dissected endothelial lamellae were ultrathin. Pachy-DSEK was safe and effective for treating endothelial disfunction in eyes with ocular comorbidities. It may be a cost-effective alternative to automated dissection methods.

Limbal transplantation at a tertiary hospital in Brazil: a retrospective study.

PURPOSE: Epidemiological analysis of limbal transplantation surgeries performed in the Ophthalmologic Hospital of Sorocaba. METHODS: Retrospective medical records review of 30 patients who underwent limbal stem cell transplants between January 2003 and March 2008. Cases involving conjunctival limbal autograft were classified as group I, and those involving conjunctival limbal allograft as group II. RESULTS: Two patients were excluded due to incomplete data during postoperative follow-up. Of the total sample of 28 patients, 53.6% constituted group I, whereas 46.4% were included in group II. Males were predominant (67.9%), and right eyes were the most prevalent (67.9%). The mean age was 40.3 years. Unilateral cases accounted for 60.7%. The most frequent pathology causing limbal system failure was chemical burns (53%). The mean length of time from diagnosis to surgery was 11.18 years. The limbal graft and amniotic membrane were associated in 75% of all cases, and tarsorrhaphy in 57.1%. The average follow-up period was 24.84 months. The uncorrected visual acuity improved in 38% of the cases, was unchanged in 28.5%, and deteriorated in 33.3%. There was no persistent epithelial defect in 75% of the patients. The conjunctivalization rate was similar between the groups (53.3% and 58.3%, respectively). The transparency improved in only 38.4% of the cases, and 28.5% of the surgeries performed were successful. The most prevalent complication was persistent epithelial defect, which occurred in 25% of the patients, followed by corneal melting in 14.2%. Other complications observed included infectious ulcers, limbal graft necrosis or ischemia, perforation, and descemetocele. CONCLUSION: Chemical burns remain the main cause of limbal stem cell deficiency. In these cases, limbal transplantation is the standard procedure to restore the ocular surface even though the success rate is low.

Limbal transplantation at a tertiary hospital in Brazil: a retrospective study / Transplante de limbo em hospital terciário no Brasil: estudo retrospectivo

ABSTRACTPurpose:Epidemiological analysis of limbal transplantation surgeries performed in the Ophthalmologic Hospital of Sorocaba.Methods:Retrospective medical records review of 30 patients who underwent limbal stem cell transplants between January 2003 and March 2008. Cases involving conjunctival limbal autograft were classified as group I, and those involving conjunctival limbal allograft as group II.Results:Two patients were excluded due to incomplete data during postoperative follow-up. Of the total sample of 28 patients, 53.6% constituted group I, whereas 46.4% were included in group II. Males were predominant (67.9%), and right eyes were the most prevalent (67.9%). The mean age was 40.3 years. Unilateral cases accounted for 60.7%. The most frequent pathology causing limbal system failure was chemical burns (53%). The mean length of time from diagnosis to surgery was 11.18 years. The limbal graft and amniotic membrane were associated in 75% of all cases, and tarsorrhaphy in 57.1%. The average follow-up period was 24.84 months. The uncorrected visual acuity improved in 38% of the cases, was unchanged in 28.5%, and deteriorated in 33.3%. There was no persistent epithelial defect in 75% of the patients. The conjunctivalization rate was similar between the groups (53.3% and 58.3%, respectively). The transparency improved in only 38.4% of the cases, and 28.5% of the surgeries performed were successful. The most prevalent complication was persistent epithelial defect, which occurred in 25% of the patients, followed by corneal melting in 14.2%. Other complications observed included infectious ulcers, limbal graft necrosis or ischemia, perforation, and descemetocele.Conclusion:Chemical burns remain the main cause of limbal stem cell deficiency. In these cases, limbal transplantation is the standard procedure to restore the ocular surface even though the success rate is low.

RESUMOObjetivo:Análise epidemiológica dos transplantes de limbo realizados no Hospital Oftalmológico de Sorocaba.Método:Foi realizada uma análise retrospectiva através de revisão de prontuário de trinta casos de transplante de limbo realizados no período de janeiro de 2003 a março de 2008. Casos de transplante de limbo autólogo foram classificados como grupo I e alogênicos como grupo II.Resultados:Dois pacientes foram excluídos da análise por insuficiência de dados nos registros. Da amostra completa de 28 pacientes, 53,6% constituíram o grupo I enquanto 46,4% o grupo II. O olho direito (68%) e o sexo masculino (68%) foram mais acometidos, com uma média de idade de 40,3 anos. Casos unilaterais contabilizaram 60,7%. A patologia de base causadora da deficiência límbica mais prevalente foi a queimadura química (53%). A média do tempo de doença até a cirurgia foi de 11,18 anos. Na maioria dos casos o transplante foi associado a membrana amniótica (75%) e tarsorrafia (57%). O tempo médio de seguimento foi de 24,84 meses. Foi observado melhora da acuidade visual não corrigida em 38% dos casos enquanto 28,5% permaneceram inalteradas e 33,3% pioraram. Evolução sem defeito epitelial persistente ocorreu em 75% dos pacientes. A taxa de conjuntivalização foi semelhante nos 2 grupos (53,3% e 58,3%). Em apenas 38% dos casos houve melhora da transparência. A taxa de sucesso foi de cerca de 28%. A complicação mais prevalente foi defeito epitelial persistente (25%) seguida de melting (14,2%). Outras complicações observadas foram úlceras infecciosas, necrose ou isquemia do enxerto, perfuração e descemetocele.Conclusões:A queimadura química permanece como principal patologia causadora de deficiência límbica. Nestes casos o transplante de limbo é atualmente a técnica de eleição para restauração da superfície ocular, porém com baixa taxa de sucesso.

Efeito da trepanação na previsibilidade da correção da ametropia esférica pós-transplante / Effect of recipient-donor trephine disparity on the prediction of refractive errors after penetrating keratoplasty

OBJETIVO: Demonstrar a redução e previsibilidade da ametropia esférica com melhora da acuidade visual promovida pelo transplante penetrante (TP) de córnea por ceratocone e o efeito da relação diâmetro doador-receptor neste resultado. MÉTODOS: Estudo retrospectivo revisando aleatoriamente os prontuários de 60 pacientes submetidos ao TP por ceratocone, realizados pelo mesmo cirurgião, com a mesma técnica cirúrgica, entre 2005 e 2008. Foram avaliados estatisticamente: ceratometria, equivalente esférico e acuidade visual no pré, pós-operatório de 1, 3 e 6 meses. Os grupos foram então divididos conforme a diferença de trepanação entre diâmetro do doador e receptor, sendo o grupo 1 composto por pacientes com diferença de zero ou 0,25mm (8,0/8,0 e 8,25/8,0mm) e o grupo 2 por pacientes com diferença de 0,5mm (8,0/8,5mm). RESULTADOS: Observou-se redução significativa da ceratometria média e equivalente esférico e melhora da acuidade visual dos pacientes com ceratocone submetidos ao TP. No sexto mês a redução do equivalente esférico foi de 79 por cento em relação ao pré-operatório. Cada dia de pós-operatório está associado à hipermetropização de 0,68D (p=0,005). Entretanto, a diferença entre os grupos não foi significativa. Em relação a ceratometria, cada dia de pós-operatório associou-se a um declínio de 1,87D (p<0,0001) que variou entre os grupos significativamente (p=0,007). O grupo 1 apresentou redução de 8,93D na ceratometria média, comparado a redução de 6,81D no grupo 2 (p=0,035). CONCLUSÃO : O planejamento da trepanação pode proporcionar redução significativa da elevada ametropia que comumente acompanha o pós-operatório do TP por ceratocone, permitindo assim correção ótica satisfatória.

PURPOSE : To demonstrate the reduction and prediction of refractive errors after penetrating keratoplasty (PK) for keratoconus and evaluate the effect of recipient-donor trephine disparity on the results. METHODS: Retrospective analysis of clinical records of 60 patients that underwent PK for keratoconus performed by the same surgeon, under the same technique, between 2005 and 2009. Spherical equivalent, keratometry and visual acuity were evaluated statistically before surgery and 1.3 and 6 months after. The patients were divided in two groups according to recipient-donor trephine disparity. Group 1 formed by those with disparity smaller than 0,5mm and group 2 with disparity equal to 0.5mm. RESULTS: All patients showed improvement on visual acuity. The hypermetropic effect observed on the 6th postoperative month was of 79 percent. Both groups showed significant reduction of refractive error, each postoperative day correspond to a hypermetropic effect of 0.68D (p=0.005). Neither the spherical equivalent mean difference between the groups nor the difference of the hypermetropic effect between the groups was statistically significant. Analysing the keratometry, each postoperative day is associated to a decrease of 1.87D (p<0.0001 showing significant difference between groups (p=0.007). Group 1 showed a reduction of 8.93D on mean keratometry compared to the 6.82D reduction observed on group 2 (p=0.035). CONCLUSION: We observed a significant reduction on mean keratometry and spherical equivalent as well as the improvement in visual acuity in keratoconus patients that underwent PK. The preoperative planning of trephine size may provide a significant reduction on refractive error after PK for keratoconus.