Optical biometry-based axial length alterations after intravitreal dexamethasone implant / Alterações do comprimento axial com base na biometria óptica após o implante de dexametasona intravítrea

ABSTRACT Purpose: To investigate changes in axial length after intravitreal dexamethasone implantation in patients with macular edema. Methods: We performed a prospective comparative study of 46 patients with unilateral macular edema, due to diabetic retinopathy, retinal vein occlusion, and non-infectious uveitis, who underwent dexamethasone implantation. The fellow eyes of the patients were considered the control group. The central macular thickness was measured by spectral-domain optical coherence tomography, and axial length was measured by IOLMaster 700 optical coherence biometry. We compared axial length and central macular thickness values within the groups. Results: In the study group, the baseline central macular thickness was 460.19 ± 128.64 mm, significantly decreasing to 324.00 ± 79.84 mm after dexamethasone implantation (p=0.000). No significant change in central macular thickness measurements was seen in the control group (p=0.244). In the study group, the baseline axial length was 23.16 ± 0.68 mm, significantly increasing to 23.22 ± 0.65 mm after dexamethasone implantation (p=0.039). However, the control group exhibited no significant change in axial length (p=0.123). Conclusions: In addition to significantly reducing central macular thickness measurements, intravitreal dexamethasone implantation also significantly changes optical biometry-based axial length measurements.

RESUMO Objetivo: Investigar alterações no comprimento axial após implante de dexametasona intravítrea em pacientes com edema macular. Métodos: Foi realizado um estudo prospectivo e comparativo de 46 pacientes com edema macular unilateral, devido à retinopatia diabética, oclusão da veia retiniana e uveíte não infecciosa, que foram submetidos ao implante de dexametasona. Os olhos contralateral de cada paciente foram considerados o grupo controle. A espessura macular central foi medida por tomografia de coerência óptica de domínio espectral, e o comprimento axial foi medido por meio de biometria de coerência óptica de domínio espectral e o comprimento axial foi medido pela biometria de coerência óptica com IOLMaster 700. Comparamos o comprimento axial e os valores da espessura macular central dentro dos grupos. Resultados: No grupo de estudo, a espessura macular basal foi de 460,19 ± 128,64 mm, diminuindo significativamente para 324,00 ± 79,84 mm após o implante de dexametasona (p=0,000). Nenhuma mudança significativa nas medidas da espessura macular central foi observada no grupo controle (p=0,244). No grupo de estudo, o comprimento axial basal foi de 23,16 ± 0,68 mm, aumentando significativamente para 23,22 ± 0,65 mm após o implante de dexametasona (p=0,039). No entanto, o grupo controle não apresentou alteração significativa no comprimento axial (p=0,123). Conclusões: Além de reduzir significativamente as medidas da espessura macular central, o implante de dexametasona intravítrea também altera significativamente as medidas de comprimento axial baseadas na biometria óptica.

Evaluation of anterior segment parameters in patients with pseudoexfoliation syndrome using Scheimpflug imaging / Avaliação de parâmetros do segmento anterior por imagem Scheimpflug em pacientes com síndrome de pseudoexfoliação

ABSTRACT Purpose: To evaluate anterior segment parameters in patients with pseudoexfoliation syndrome (PXS) using Scheimpflug imaging. Methods: Forty-three PXS patients and 43 healthy control subjects were included in this cross-sectional study. All participants underwent a detailed ophthalmologic examination. Anterior segment parameters were measured using a Scheimpflug system. Results: Considering the PXS and control groups, the mean corneal thicknesses at the apex point (536 ± 31 and 560 ± 31 µm, respectively, p=0.001), at the center of the pupil (534 ± 31 and 558 ± 33 µm, respectively, p=0.001), and at the thinnest point (528 ± 30 and 546 ± 27 µm, respectively, p=0.005) were significantly thinner in PXS patients. Visual acuity was significantly lower (0.52 ± 0.37 versus 0.88 ± 0.23, p<0.001) and axial length was significantly longer (23.9 ± 0.70 mm versus 23.2 ± 0.90 mm, p=0.001) in the PXS eyes than in the control eyes. There were no statistically significant differences in the mean values of keratometry, anterior chamber angle, anterior chamber depth, corneal volume, and anterior chamber volume between the PXS and control eyes. Conclusions: The patients with PXS had thinner corneas, worse visual acuity, and longer axial length compared with those in the healthy controls.

RESUMO Objetivo: Avaliar os parâmetros do segmento anterior em pacientes com síndrome de pseudoexfoliação (PXS) utilizando imagens de Scheimpflug. Métodos: Quarenta e três pacientes com PXS e 43 indivíduos saudáveis foram incluídos neste estudo transversal. Todos os participantes foram submetidos ao exame oftalmológico detalhado. Parâmetros do segmento anterior foram medidos por sistema de Scheimpflug. Resultados: Considerando os grupos PXS e controle, respectivamente, as espessuras médias da espessura corneana no ápice (536 ± 31 µm e 560 ± 31 µm, p=0,001), no centro da pupila (534 ± 31 µm e 558 ± 33 µm, p=0,001), e no ponto mais fino (528 ± 30 µm e 546 ± 27 µm, p=0,005), foram significativamente mais finas em pacientes com PXS. A acuidade visual foi significativamente menor (0,52 ± 0,37 contra 0,88 ± 0,23, p<0,001) e comprimento axial foi significativamente maior (23,9 ± 0,70 milímetros contra 23,2 ± 0,90 milímetros, p=0,001) em olhos com PXS comparados com os olhos controle. Não houve diferenças estatisticamente significativas entre PXS e controle olhos em valores médios de ceratometria, ângulo da câmara anterior, profundidade da câmara anterior, volume da córnea e volume de câmara anterior. Conclusões: Os pacientes com PXS tem córneas mais finas, pior acuidade visual, e maior comprimento axial em comparação com controles saudáveis.

Congenital and developmental cataract: axial length and keratometry study in Brazilian children / Catarata congênita e do desenvolvimento: estudo do comprimento axial e da ceratometria em crianças brasileiras

ABSTRACT Purpose: To evaluate the ocular axial length (AL) and keratometry (K) in Brazilian children with congenital/developmental cataract, assess the differences and evolution of AL and K according to age, and establish functional models of AL and K as function of age. Methods: Children with congenital/developmental cataract aged 1.5 months old to 8 years old and no other ocular diseases were included. All eyes with unilateral cataract, the left eyes from children with bilateral cataracts, and healthy eyes from children with unilateral cataract were analyzed. After the administration of anesthesia, K was measured with a portable automatic keratometer, and AL was measured with a contact biometer. Cataract surgery was performed immediately after the measurements were taken. The data were statistically analyzed, and a linear regression with an age logarithm was used to model the relationship. Results: Forty-four eyes with cataract were included in this analysis, comprising 15 eyes with unilateral cataract and 29 left eyes from children with bilateral cataracts. The mean age was 27.3 months with a mean AL of 20.63 ± 2.11 mm and a mean K of 44.94 ± 2.44 D. The K value was significantly steeper and the AL value was significantly shorter in younger children (P< 0.001). No significant differences were found neither between eyes with unilateral and bilateral cataracts nor between eyes with unilateral cataract and their corresponding healthy eyes (P >0.05). Conclusion: The values of K and AL significantly change with age, especially during the first 6 months of life. A linear functional relationship between K and AL with the logarithm of age and between K and AL was established.

RESUMO Objetivo: Avaliar o comprimento axial (AL) e a ceratometria (K) de olhos de crianças brasileiras com catarata congênita/desenvolvimento, analisar diferenças e evoluções de acordo com a idade e estabelecer modelos funcionais de comprimento axial e ceratometria em função da idade e entre eles. Métodos: Crianças com catarata congênita/desenvolvimento com idade de 1,5 meses a 8 anos de idade e sem outras doenças oculares foram incluídas. Todos os olhos com catarata unilateral, o olho esquerdo de crianças com catarata bilateral e o olho sadio de crianças com catarata unilateral foram analisados. Após a administração de anestesia, a ceratometria foi obtida com um ceratômetro automático portátil e o comprimento axial medido com um biômetro de contato. Em seguida, a cirurgia de catarata foi realizada. Os dados foram analisados estatisticamente, a regressão linear com o logaritmo da idade foi utilizado para modelar os relacionamentos. Resultados: Todos os olhos com catarata unilateral (n=15) e um olho selecionados aleatoriamente a partir dos casos bilaterais (n=29) foram incluídos na análise (total= 44 olhos). A idade média foi de 27,3 meses, as médias do comprimento axial e da ceratometria foram respectivamente 20,63 ± 2,11 mm e 44,94 ± 2,44 dioptrias. A ceratometria foi significativamente mais curvo e comprimento axial significantemente mais curto em crianças mais jovens (P<0,001). Não foram encontradas diferenças significativas na comparação entre os olhos com cataratas unilaterais e bilaterais e comparando os olhos com catarata unilateral a correspondentes olhos saudáveis (P>0,05). Conclusão: Os valores de ceratometria e comprimento axial mudam significativamente com a idade, principalmente nos primeiros seis meses de vida. Foi estabelecida uma relação funcional linear entre comprimento axial e ceratometria com o logaritmo da idade e entre ceratometria e comprimento axial.

Refraction and eye anterior segment parameters in schizophrenic patients / Refração e parâmetros do segmento anterior ocular em pacientes com esquizofrenia

ABSTRACT Purpose: To evaluate the difference in terms of refractive errors and anterior segment parameters between schizophrenic patients and healthy volunteers. Methods: This study compared 70 patients (48 men) who were diagnosed with schizophrenia with a control group of 60 (35 men) who were similar in terms of age, gender, education, and socioeconomic level. Anterior segment examination was performed using a Scheimflug system. Axial length and lens thickness (LT) were measured using optic biometry. The following tests were administered to the psychiatric patient group: Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS), and Scale for the Assessment of Positive Symptoms (SAPS). Results: Mild myopia was detected in both the schizophrenic and control groups, with no statistically significant difference (p>0.005). Corneal volume (CV), anterior chamber volume (ACV), anterior chamber depth (ACD), and central corneal thickness (CCT) values were lower in the schizophrenic group, and there was a statistically significant between-group difference (p=0.026, p=0.014, p=0.048, and p=0.005, respectively). LT was greater in schizophrenics, and the difference was found to be statistically significant (p=0.006). A statistically significant negative correlation was found between SAPS and cylinder values (p=0.008). The axial eye length, cylinder value, pupil diameter, mean keratometric value, and anterior chamber angle revealed no statistically significant difference between the groups (p>0.05). Conclusion: No statistically significant difference was detected in terms of refraction disorders between schizophrenics and the healthy control group, while some differences in anterior chamber parameters were present. These results demonstrate that schizophrenics may exhibit clinical and structural differences in the eye. .

RESUMO Objetivo: Avaliar se existem diferenças em relação aos erros refracionais e parâmetros do segmento anterior entre pacientes com esquizofrenia e voluntários saudáveis. Métodos: Este estudo comparou 70 pacientes diagnosticados com esquizofrenia (48 homens) com um grupo controle de 60 pacientes, semelhantes em relação à idade, sexo, escolaridade e nível socioeconômico (35 homens). O exame do segmento anterior foi realizado com o sistema Scheimflug; os comprimentos axiais do olho e a espessura do cristalino foram avaliadas por meio de biometria óptica. Os seguintes testes foram aplicados ao grupo de pacientes psiquiátricos: Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Negative Symptoms (SANS), e Scale for the Assessment of Positive Symptoms (SAPS). Resultados: Miopia leve foi detectada em ambos os grupos de esquizofrenia e de controle, sem diferença estatisticamente significativa (p>0,005). Volume de córnea (CV), volume da câmara anterior (ACV), profundidade da câmara anterior (ACD) e paquimetria central da córnea (CCT) apresentaram valores menores no grupo de esquizofrênicos e houve diferença estatisticamente significativa entre os dois grupos (p=0,026, p=0,014, p=0,048 e p=0,005, respectivamente). A espessura do cristalino (LT) foi maior em esquizofrênicos e a diferença foi estatisticamente significativa (p=0,006). Foi encontrada uma correlação negativa estatisticamente significativa entre SAPS e os valores cilíndricos (p=0,008). O comprimento axial do olho, o valor do cilindro, o diâmetro pupilar, a ceratometria média e o ângulo da câmara anterior não revelaram nenhuma diferença estatística entre os grupos (p>0,05). Conclusões: Não foi detectada diferença estatisticamente significativa em relação aos transtornos de refração entre os esquizofrênicos e o grupo controle, enquanto algumas diferenças nos parâmetros de câmara anterior estavam presentes. Estes resultados demonstram que esquizofrénicos podem ...

Estimation of Intraocular Lens Power Calculation after Myopic Corneal Refractive Surgery: Using Corneal Height in Anterior Segment Optical Coherence Tomography

PURPOSE: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery. METHODS: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELP(m)) was calculated. Intraocular lens power, which could achieve actual emmetropia (P(real)), was determined with medical records. Estimated ELP (ELP(est)) was back-calculated using P(real), axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELP(m) and ELP(est), converted ELP and intraocular lens power (ELP(conv), P(conv)) were obtained and then compared to ELP(est) and P(real), respectively. The proportion of eyes within a defined error was investigated. RESULTS: Mean CH, ELP(est), and ELP(m) were 3.71 +/- 0.23, 7.74 +/- 1.09, 5.78 +/- 0.26 mm, respectively. The ELP(m) and ELP(est) were linearly correlated (ELP(est) = 1.841 x ELP(m) - 2.018, p = 0.023, R = 0.410) and ELP(conv) and P(conv) agreed well with ELP(est) and P(real), respectively. Eyes within +/-0.5, +/-1.0, +/-1.5, and +/-2.0 diopters of the calculated P(conv), were 23.3%, 66.6%, 83.3%, and 100.0%, respectively. CONCLUSIONS: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.

Estimation of Intraocular Lens Power Calculation after Myopic Corneal Refractive Surgery: Using Corneal Height in Anterior Segment Optical Coherence Tomography

PURPOSE: To investigate the feasibility of estimating effective lens position (ELP) and calculating intraocular lens power using corneal height (CH), as measured using anterior segment optical coherence tomography (AS-OCT), in patients who have undergone corneal refractive surgery. METHODS: This study included 23 patients (30 eyes) who have undergone myopic corneal refractive surgery and subsequent successful cataract surgery. The CH was measured with AS-OCT, and the measured ELP (ELP(m)) was calculated. Intraocular lens power, which could achieve actual emmetropia (P(real)), was determined with medical records. Estimated ELP (ELP(est)) was back-calculated using P(real), axial length, and keratometric value through the SRK/T formula. After searching the best-fit regression formula between ELP(m) and ELP(est), converted ELP and intraocular lens power (ELP(conv), P(conv)) were obtained and then compared to ELP(est) and P(real), respectively. The proportion of eyes within a defined error was investigated. RESULTS: Mean CH, ELP(est), and ELP(m) were 3.71 +/- 0.23, 7.74 +/- 1.09, 5.78 +/- 0.26 mm, respectively. The ELP(m) and ELP(est) were linearly correlated (ELP(est) = 1.841 x ELP(m) - 2.018, p = 0.023, R = 0.410) and ELP(conv) and P(conv) agreed well with ELP(est) and P(real), respectively. Eyes within +/-0.5, +/-1.0, +/-1.5, and +/-2.0 diopters of the calculated P(conv), were 23.3%, 66.6%, 83.3%, and 100.0%, respectively. CONCLUSIONS: Intraocular lens power calculation using CH measured with AS-OCT shows comparable accuracy to several conventional methods in eyes following corneal refractive surgery.

Accuracy of Biometry for Intraocular Lens Implantation Using the New Partial Coherence Interferometer, AL-scan

PURPOSE: To compare the refractive results of cataract surgery measured by applanation ultrasound and the new partial coherence interferometer, AL-scan. METHODS: Medical records of 76 patients and 104 eyes who underwent cataract surgery from January 2013 to June 2013 were retrospectively reviewed. Biometries were measured using ultrasound and AL-scan and intraocular lens power was calculated using the SRK-T formula. Automatic refraction examination was done 1 month after the operation, and differences between the ultrasound group and AL-scan group were compared and analyzed by mean absolute error. RESULTS: Mean axial length measured preoperatively by the ultrasound method was 23.53 +/- 1.17 mm while the lengths measured using the AL-scan were 0.03 mm longer than that of the ultrasound group (23.56 +/- 1.15 mm). However, there was not a significant difference in this finding (p = 0.638). Mean absolute error was 0.34 +/- 0.27 diopters in the ultrasound group and 0.36 +/- 0.31 diopters in AL-scan group, which showed no significant difference (p = 0.946) in precision of predicting postoperative refraction. CONCLUSIONS: Although the difference was not statistically significant, intraocular lens calculations done by the AL-scan were nearly similar in predicting postoperative refraction compared to those of applanation ultrasound, however more precise measurements may be obtained if the axial length is longer than 24.4 mm. Except in the case of opacity in the media, which makes obtaining measurements with the AL-scan difficult, AL-scan could be a useful biometry in cataract surgery.