ABSTRACT
ABSTRACT Purpose: To assess the effect of hemodialysis on retinal and choroidal thicknesses using spectral-domain optical coherence tomography (SD-OCT). Methods: In this prospective interventional study, 25 hemodialysis patients (17 male, 8 female) were enrolled. All participants underwent high-speed, high-resolution SD-OCT (λ=840 mm; 26.000 A-scans/s; 5 µm resolution) before and after hemodialysis. Choroidal thickness was measured perpendicularly from the outer edge of the retinal pigment epithelium to the choroid-sclera boundary at the fovea and at five additional points: 500 µm and 1000 µm nasal to the fovea and 500 µm, 1000 µm, and 1500 µm temporal to the fovea. Two masked physicians performed the measurements. Choroidal and retinal thicknesses before and after hemodialysis were compared. Results: The median choroidal thicknesses before and after hemodialysis were 182 µm (range, 103-374 µm) and 161 µm (range, 90-353 µm), respectively (P<0.001). The median retinal thicknesses were 246 µm (range, 179-296 µm) before and 248 µm (range, 141-299 µm) after hemodialysis (P>0.05). Systolic arterial pressure, diastolic arterial pressure, mean arterial pressure, heart rate, and ocular perfusion pressure significantly decreased after hemodialysis (P<0.001). Intraocular pressure did not vary significantly (P=0.540). Conclusion: Hemodialysis seems to cause a significant decrease in choroidal thickness, whereas it has no effect on retinal thickness. This significant decrease in choroidal thickness might be due to the extensive fluid absorption in hemodialysis, which could result in decreased ocular blood flow.
RESUMO Objetivo: Avaliar o efeito da hemodiálise (HD) na espessura da retina (RT) e na espessura da coroide (CT) usando tomografia de coerência óptica de domínio espectral (SD-OCT). Método: Neste estudo prospectivo intervencionista foram incluídos 25 pacientes em HD (17 homens e 8 mulheres). Todos os participantes foram submetidos a SD-OCT com dispositivo de alta resolução (λ=840 mm; 26.000 A-scans/seg e resolução de 5 µm), antes e após HD. A CT foi medida perpendicularmente a partir da borda externa do epitélio pigmentar da retina até o limite coroide-esclera na fóvea e em mais de 5 pontos localizados 500 µm nasal à fóvea, 1.000 µm nasal à fóvea; 500 µm temporal à fóvea, 1.000 µm temporal à fóvea, e 1.500 µm temporal à fóvea. Dois médicos realizaram as medidas sem o conhecimento do diagnóstico. Os dados da CT e RT, antes e após a HD foram comparados. Resultados: As CTs medianas antes e após a HD foram 182 µm (variação de 103-374 µm) e 161 µm (variação de 90-353 µm), respectivamente (p<0,001). A RT foi 246 µm (variação de 179-296 µm) antes e 248 µm (variação de 141-299 µm) após a HD (p>0,05). A pressão arterial sistólica, pressão arterial diastólica, as médias de pressão arterial média, frequência cardíaca e pressão de perfusão ocular diminuíram significativamente após HD (p<0,001). A pressão intraocular não alterou significativamente (p=0,540). Conclusão: A HD parece causar uma redução significativa da CT, e não ter efeito sobre a RT. Esta redução significativa da CT pode ser devida à grande absorção de fluido durante a HD, o que pode resultar numa diminuição do fluxo sanguíneo ocular.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Young Adult , Retina/anatomy & histology , Retina/diagnostic imaging , Choroid/anatomy & histology , Choroid/diagnostic imaging , Renal Dialysis/adverse effects , Organ Size , Reference Values , Retina/physiopathology , Time Factors , Observer Variation , Prospective Studies , Choroid/physiopathology , Statistics, Nonparametric , Tomography, Optical Coherence/methods , Eye/blood supply , Hemodynamics , Intraocular Pressure , Kidney Failure, Chronic/physiopathology , Kidney Failure, Chronic/therapyABSTRACT
Aims: To investigate the effect of surgery type on the postoperative astigmatism in pterygium surgery. Settings and Design: Retrospective comparative clinical trial. Materials and Methods: Data of 240 eyes that underwent pterygium excision were investigated. Following removal of the pterygium, patients underwent 5 different types of surgeries: Conjunctival autograft with sutures (CAG-s) or fibrin glue (CAG-g), conjunctival rotational flap (CRF), or amniotic membrane transplantation with either suture (AMT-s) or with glue (AMT-g). The preoperative and postoperative keratometric measurements, evaluated using an automated keratorefractometer, were noted. Statistical Analysis: The overall changes in BCVA and astigmatic degree were evaluated using Wilcoxon signed rank test. The difference in astigmatic values between groups was calculated using one way analysis of variance (ANOVA). Results: The most commonly performed procedure was CAG-s (N = 115), followed by CAG-g (N = 53), CRF (N = 47), AMT-s (N = 15), and AMT-g (N = 10). Following surgery, astigmatic values decreased from 3.47 ± 2.50 D to 1.29 ± 1.07 D (P < 0.001, paired t test). The changes in astigmatism was significantly related to the preoperative size of the pterygium (ρ = 3.464, P = 0.005). The postoperative astigmatism correlated with preoperative astigmatism (ρ = 0.351, P < 0.001, Spearman correlation analysis). The changes in astigmatic values was not related to the method of surgery (P = 0.055, ANOVA). Conclusion: Pterygium results in high corneal astigmatism, which decreases to an acceptable level following excision. According to our study, the type of grafting as CAG, CRF or AMT or the use of suture or glue to fixate the graft does not have a significant effect on the change in astigmatism degree.