Equivalent keratometer reading para cálculo biométrico em córneas assimétricas: série de casos / Equivalent keratometer reading tool for biometric calculation in asymmetric corneas: case series

RESUMO A acurácia do cálculo da lente intraocular não é perfeita, podendo ser comuns erros refrativos pós-operatórios, especialmente em pacientes submetidos à cirurgia refrativa prévia ou na presença de córneas assimétricas. O poder corneano após cirurgia refrativa pode ser medido com maior acurácia utilizando o mapa de poder óptico total na zona central de 4mm, com Orbscan II ou pelo mapa equivalent keratometric reading disponível no pentacam, com medidas centrais de 1,0, 2,0, 3,0 e 4,5mm. O objetivo desta série de casos é demonstrar a abordagem de quatro olhos em condições especiais corneanas, por meio do equivalent keratometric reading do pentacam para mensuração do poder corneano e o utilizando na biometria, em comparação com possíveis resultados obtidos com outras estratégias. Os quatro olhos foram submetidos a procedimentos refrativos prévios, e a lente intraocular escolhida a partir do uso do poder corneano calculado pelo equivalent keratometric reading mostrou excelentes resultados pós-operatórios.

ABSTRACT The accuracy of the intraocular lens calculation is not perfect, and postoperative refractive errors are common, especially in patients who have undergone previous refractive surgery or in presence of asymmetric corneas. Corneal power after refractive surgery can be more accurately measured using the total optical power map in the 4-mm central zone, by means of Orbscan II or equivalent keratometric reading map available on pentacam, with central measurements of 1.0, 2.0, 3.0 and 4.5 mm. The purpose of this case series is to demonstrate four approaches performed in special corneal conditions, using pentacam equivalent keratometric reading to measure corneal power and biometrics, and comparing with possible results obtained with other strategies. The four eyes were submitted to previous refractive procedures, and the intraocular lens chosen from the use of the corneal power calculated by equivalent keratometric reading showed excellent postoperative results.

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 ...

Effect of Watching 3-Dimensional Television on Refractive Error in Children

PURPOSE: To investigate the effect of watching 3-dimensional (3D) television (TV) on refractive error in children. METHODS: Sixty healthy volunteers, aged 6 to 12 years, without any ocular abnormalities other than refractive error were recruited for this study. They watched 3D TV for 50 minutes at a viewing distance of 2.8 meters. The image disparity of the 3D contents was from -1 to 1 degree. Refractive errors were measured both before and immediately after watching TV and were rechecked after a 10-minute rest period. The refractive errors before and after watching TV were compared. The amount of refractive change was also compared between myopes and controls. The refractive error of the participants who showed a myopic shift immediately after watching TV were compared across each time point to assure that the myopic shift persisted after a 10-minute rest. RESULTS: The mean age of the participants was 9.23 ± 1.75 years. The baseline manifest refractive error was -1.70 ± 1.79 (-5.50 to +1.25) diopters. The refractive errors immediately after watching and after a 10-minute rest were -1.75 ± 1.85 and -1.69 ± 1.80 diopters, respectively, which were not different from the baseline values. Myopic participants (34 participants), whose spherical equivalent was worse than -0.75 diopters, also did not show any significant refractive change after watching 3D TV. A myopic shift was observed in 31 participants with a mean score of 0.29 ± 0.23 diopters, which resolved after a 10-minute rest. CONCLUSIONS: Watching properly made 3D content on a 3D TV for 50 minutes with a 10-minute intermission at more than 2.8 meters of viewing distance did not affect the refractive error of children.

Influence of aspheric intraocular lens on frequency doubling technology and contrast sensitivity: a fellow eye study / Influência da lente intraocular asférica na perimetria de frequência dupla e sensibilidade ao contraste: estudo contralateral

Purpose: To evaluate whether implantation of an aspheric intraocular lens (IOL) results in reduced ocular aberrations and improved contrast sensitivity after cataract surgery and, therefore, changes on frequency-doubling technology (FDT) testing. Methods: The present prospective clinical study enrolled 25 patients with bilateral cataract (50 eyes), who randomly received either an aspheric (Akreos AO) or a spherical (Akreos Fit) IOL in one eye and the other IOL in the second eye. Assessment 12 months postoperatively included photopic and mesopic contrast sensitivity testing. Higher-order aberrations (HOAs) were computed. FDT testing was divided into four areas to evaluate the variation of the values at different points. The median values of the local pattern thresholds (median area contrast sensitivity [MACS]) obtained with that division were calculated. Results: The Akreos AO group obtained statistically significantly lower values of HOAs and spherical aberration compared with the Akreos Fit group. There was a statistically significant between-group difference in contrast sensitivity under mesopic conditions at all spatial frequencies. No statistically significant differences were observed in mean deviation and pattern standard deviation. The aspheric IOL exhibited higher MACS in all areas, although a statistically significant difference was reached only in the 20-degree field area (P=0.043). Conclusion: Aspheric IOLs significantly reduced spherical aberration and HOAs, improving mesopic contrast sensitivity. Although there was a trend toward slightly improved FDT in the aspheric IOL group, it was not statistically significant. .

Objetivo: Avaliar se o implante de uma lente intraocular (LIO) asférica reduz a aberração ocular (alta ordem e esférica), melhora a sensibilidade ao contraste e consequentemente, provoca mudanças nos valores da perimetria de frequência dupla (FDT ). Métodos: Trata-se de um estudo prospectivo envolvendo 25 pacientes com catarata bilateral (50 olhos) que foram randomizados para receberem uma LIO asférica (Akreos AO) em um olho e uma LIO esfércia (Akreos Fit) no olho contralateral. Com 12 meses de pós-operatório a sensibilidade ao contraste (condições fotópicas e mesópicas) e a aberração de alta ordem foram computados. A FDT foi dividida em 4 áreas para análise da variação dos valores em diferentes localizações. Os valores médios dos limiares locais (área média de sensibilidade ao contraste [MACS]) obtidos com essa divisão foram calculados. Resultados: O grupo da Akreos AO apresentou menores valores de aberração de alta ordem e aberração esférica. Houve diferença estatisticamente significativa na sensibilidade ao contraste em condições mesópicas em todas frequências. Não houve diferença estatística nos valores do mean deviation e pattern standard deviation da FDT. A LIO asférica apresentou maiores MACS em todas as áreas, embora diferença estatística foi encontrada apenas na área de 20 graus de campo visual (P=0,043). Conclusões: A lente asférica reduziu significativamente a quantidade de aberração de alta ordem e esférica, melhorando a sensibilidade ao contraste em condições mesópicas. Embora houve uma melhora nos valores da FDT no grupo da LIO asférica, essa diferença não foi estatisticamente significativa. .

Angle Kappa and its importance in refractive surgery

Angle kappa is the difference between the pupillary and visual axis. This measurement is of paramount consideration in refractive surgery, as proper centration is required for optimal results. Angle kappa may contribute to MFIOL decentration and its resultant photic phenomena. Adjusting placement of MFIOLs for angle kappa is not supported by the literature but is likely to help reduce glare and haloes. Centering LASIK in angle kappa patients over the corneal light reflex is safe, efficacious, and recommended. Centering in-between the corneal reflex and the entrance pupil is also safe and efficacious. The literature regarding PRK in patients with an angle kappa is sparse but centering on the corneal reflex is assumed to be similar to centering LASIK on the corneal reflex. Thus, centration of MFIOLs, LASIK, and PRK should be focused on the corneal reflex for patients with a large angle kappa. More research is needed to guide surgeons' approach to angle kappa

Laser in-situ keratomileusis for refractive error following radial keratotomy.

Aim: To evaluate the safety and efficacy of laser in-situ keratomileusis (LASIK) in eyes with residual/induced refractive error following radial keratotomy (RK). Design: Retrospective study. Materials and Methods: A retrospective analysis of data of 18 eyes of 10 patients, who had undergone LASIK for refractive error following RK, was performed. All the patients had undergone RK in both eyes at least one year before LASIK. Parameters like uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), contrast sensitivity, glare acuity and corneal parameters were evaluated both preoperatively and postoperatively. Statistical Software: STATA-9.0. Results: The mean UCVA before LASIK was 0.16±0.16 which improved to 0.64 ± 0.22 (P < 0.001) after one year following LASIK. Fourteen eyes (out of 18) had UCVA of ≥ 20/30 on Snellen's acuity chart at one year following LASIK. The mean BCVA before LASIK was 0.75 ± 0.18. This improved to 0.87 ± 0.16 at one year following LASIK. The mean spherical refractive error at the time of LASIK and at one year after the procedure was –5.37 ± 4.83 diopters (D) and –0.22 ± 1.45D, respectively. Only three eyes had a residual spherical refractive error of ≥ 1.0D at one year follow-up. In two eyes, we noted opening up of the RK incisions. No eye developed epithelial in-growth till 1 year after LASIK. Conclusion: LASIK is effective in treating refractive error following RK. However, it carries the risk of flap-related complications like opening up of the previously placed RK incisions and splitting of the corneal flap.

Ocular disorders in children with learning disabilities in special education schools of Pune, India.

Aim: The aim was to study and treat ocular disorders in children with learning disabilities (cLDs) and explore associations with their perinatal history. Materials and Methods: cLDs attending 11 special schools were examined by a team consisting of an ophthalmologist, optometrist, and a social worker in 2007 and followed up in 2008. The students‘ intelligence quotient (IQ) and their medical histories were noted. Distant visual acuities were measured using Kay pictures or Snellen's tumbling E chart and complete ocular examination was performed. Students were assessed at the pediatric ophthalmology unit and low vision center, if needed. Statistical analysis was done with SPSS and the Chi-square test for ordinal data. Results: A total of 664 students were examined, 526 of whom were <16 years of age; 323 (61.4%) were male. A total of 326 (60%) had moderate-to-severe learning disabilities (IQs <50), and the mean IQ was 45.4. Two hundred and thirty-eight (45.3%) had ocular disorder; 143 (27.3%) had an uncorrected refractive error, followed by strabismus in 83 (15.8%), nystagmus in 36 (6.8%), optic atrophy in 34 (6.5%), and congenital anomalies in 13 (2.5%), 103 children had more than one abnormality. Only 12 of the 143 students with refractive errors were using spectacles. A total of 132 (48.7%) children with a history of perinatal insult had ocular problems. Ocular disorders were also common in those with a history of epilepsy, Down's syndrome, and cerebral palsy. Conclusion: Nearly half the cLDs in this study had ocular disorders and one-fourth had their vision improved.

Correlation between ocular parameters and amplitude of accommodation.

Aim: To study the relationship between ocular parameters and amplitude of accommodation (AA) in the peri-presbyopic age group (35–50 years). Materials and Methods: Three hundred and sixteen right eyes of consecutive patients in the age group 35–50 years, who attended our outpatient clinic, were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 20/20, J1 in both eyes were included. The AA was calculated by measuring the near point of accommodation. The axial length (AL), central anterior chamber depth (CACD) and lens thickness (LT) were also measured. Results: There was moderate correlation (Pearson’s correlation coefficient r = 0.56) between AL and AA as well as between CACD and AA (r = 0.53) in myopes in the age group 35–39 years. In the other age groups and the groups taken as a whole, there was no correlation. In hypermetropes and emmetropes, there was no correlation between AA and the above ocular parameters. No significant correlation existed between LT and AA across different age groups and refractive errors. Conclusion: There was no significant correlation between AA and ocular parameters like anterior chamber depth, AL and LT.

Refractive error changes in children with intermittent exotropia under overminus lens therapy / Alterações nos vícios refracionais em crianças com exotropia intermitente submetidas ao tratamento por meio da hipercorreção com lentes negativas

PURPOSE: Intermittent exotropia may be decreased by stimulation of accommodative convergence. Once excessive accommodation has been related to myopia, our objective was to evaluate refractive errors changes in children under overcorrecting minus lens therapy. METHODS: A retrospective chart review of 21 children with intermittent exotropia was performed. All patients were treated with occlusion, and a 13-patient subset of them received overminus lens therapy (group A). Eight children received spectacles as necessary (group B). Initial age, age interval, initial spherical equivalent (SE), and magnitude of overcorrection were considered as co-variables of the mean variation in refractive error (SE of each eye) between groups, through a multivariate analysis. RESULTS: Overcorrection used in group A ranged from 0.5 D to 3.5 D (2.46 ± 0.87 D). Although initial SE of each eye was significant different between group A and B (OD - p=0.02; OS - p=0.01), initial age (p=0.69), age interval (p=0.90), and mean variation in refractive errors (p=0.36) did not differ between groups. Multivariate analysis with linear regression showed no significantly difference regarding all co-variables enrolled. CONCLUSIONS: Treatment of intermittent exotropia with overcorrecting minus lens did not induce refractive errors changes, even considering age, treatment period, initial spherical equivalent and overcorrection magnitude used.

OBJETIVO: A exotropia intermitente pode ser diminuída pela estimulação da convergência acomodativa. Uma vez que uma acomodação excessiva tem sido relacionada à miopização, o objetivo deste trabalho foi o de avaliar alterações nos vícios de refração de crianças submetidas à hipercorreção com lentes negativas. MÉTODOS: Foi realizada revisão dos prontuários de 21 crianças com exotropia intermitente. Todos os pacientes foram tratados com oclusão, sendo que 13 deles foram submetidos à hipercorreção com lentes negativas (grupo A). As 8 crianças restantes receberam prescrições ópticas conforme necessário pelas suas ametropias (grupo B). A idade inicial, tempo de tratamento, equivalente esférico (EE) inicial e magnitude da hipercorreção foram considerados como covariáveis na análise das diferenças das médias de erro refrativo (EE de cada olho) entre os grupos, pela análise multivariada. RESULTADOS: A hipercorreção utilizada no grupo A variou entre 0,5 D e 3,5 D (2,46 ± 0,87 D). Embora o EE inicial de cada olho ter sido significativamente diferente entre os grupo A e B (olho direito - p=0,02; olho esquerdo - p=0,01), a idade inicial (p=0,69), o tempo de tratamento (p=0,90) e a variação média nos erros refrativos (p=0,36) não diferiram entre os grupos. A análise multivariada com regressão linear não mostrou diferença significativa, considerando as covariáveis em questão. CONCLUSÕES: O tratamento de crianças com exotropia intermitente por meio de hipercorreção óptica com lentes negativas não induziu alterações nos vícios de refração, mesmo considerando fatores como idade inicial, o tempo de tratamento, equivalente esférico inicial e a magnitude da hipercorreção utilizada.

A contralateral eye study comparing apodized diffrative and full diffrative lenses: wavefront analysis and distance and near uncorrected visual acuity

PURPOSE: To evaluate intraindividual visual acuity, wavefront errors and modulation transfer functions in patients implanted with two diffractive multifocal intraocular lenses. METHODS: This prospective study examined 40 eyes of 20 cataract patients who underwent phacoemulsification and implantation of a spherical multifocal ReSTOR intraocular lens in one eye and an aspheric Tecnis ZM900 multifocal intraocular lens in the other eye. The main outcome measures, over a 3-month follow-up period, were the uncorrected photopic distance and near visual acuity and the defocus curve. The visual acuity was converted to logMAR for statistical analysis and is presented in decimal scale. The wavefront error and modulation transfer function were also evaluated in both groups. RESULTS: At the 3-month postoperative visit, the mean photopic distance uncorrected visual acuity (UCVA) was 0.74 ± 0.20 in the ReSTOR group and 0.76 ± 0.22 in the Tecnis group (p=0.286). The mean near UCVA was 0.96 ± 0.10 in the ReSTOR group and 0.93 ± 0.14 in the Tecnis group (p=0.963). The binocular defocus curve showed measurements between the peaks better than 0.2 logMAR. The total aberration, higher-order aberration and coma aberration were not significantly different between the groups. The spherical aberration was significantly lower in the Tecnis group than in the ReSTOR group. (p=0.004). Both groups performed similarly for the modulation transfer function. CONCLUSION: The ReSTOR SN60D3 and Tecnis ZM 900 intraocular lenses provided similar photopic visual acuity at distance and near. The diffractive intraocular lenses studied provided a low value of coma and spherical aberrations, with the Tecnis intraocular lens having a statistically lower spherical aberration compared to the ReSTOR intraocular lens. In the 5 mm pupil diameter analyses, both intraocular lens groups showed similar modulation transfer functions.

Desempenho visual de lentes de contato gelatinosas de diferentes tipos baseado na análise de frentes de onda / Optical performance of different soft contact lenses based on wavefront analysis

OBJETIVOS: Avaliar e comparar o desempenho visual, por meio da análise de frentes de onda, de seis diferentes tipos de lentes de contato gelatinosas [Cooperflex® (Coopervision), Frequency® 55 Aspheric (Coopervision), World Vision FW® (World Vision), Pure Vision® (Bausch & Lomb), Focus® Monthly (Ciba Vision), Focus® Choice AB (Ciba Vision)]. MÉTODOS: Realizou-se estudo prospectivo em amostra constituída por 130 olhos de 71 indivíduos portadores de miopia ou hipermetropia até 6,00D e astigmatismo até 1,50D, com acuidade visual corrigida com óculos igual ou superior a 20/20. Os sujeitos foram inicialmente submetidos ao exame clínico oftalmológico e posteriormente, ao exame de análise de frentes de onda com o aberrômetro LADARWave® (Alcon), em duas condições: sem correção óptica e em uso de um dos tipos de lente de contato incluídos no estudo, com grau correspondente ao equivalente esférico do paciente e corrigido pela distância vértice. Para análise de resultados os indivíduos foram divididos em seis grupos similares, sendo testado em cada grupo um dos tipos de lente incluídos no estudo. RESULTADOS: Mudanças nos valores das aberrações de alta ordem foram verificadas durante uso das lentes de contato. De 130 olhos estudados, 78 apresentaram aumento no valor de RMS total durante o uso da lente. Os seis tipos de lente estudados demonstraram tendência ao aumento no valor médio de RMS total durante seu uso, sem diferença estatisticamente significante entre as mesmas. O estudo demonstrou tendência ao aumento no valor médio das aberrações tipo "coma" durante o uso das lentes. As lentes Frequency® Aspheric e Cooperflex® apresentaram melhor desempenho visual em relação ao "coma". O estudo demonstrou tendência à diminuição no valor médio das aberrações esféricas durante o uso das lentes, sendo esta tendência maior nos pacientes míopes em relação aos hipermétropes. Foi demonstrado tendência ao aumento no valor médio de outras aberrações de alta ordem...

PURPOSE: To evaluate the visual performance by wavefront analyses of six different kinds of soft contact lenses: Cooperflex® (Cooper Vision), Frequency® 55 Aspheric (Cooper Vision), World Vision FW® (World Vision), Pure Vision® (Bausch & Lomb), Focus® Monthly (Ciba Vision) and Focus® Choice AB (Ciba Vision). METHODS: A prospective study was performed with 130 eyes of 71 myopic or hyperopic patients with astigmatism until 1.50 diopter and best corrected visual acuity 20/20 or better. The patients first underwent ophthalmic examination and then wavefront analyses without visual correction and wearing one of the different contact lenses included in the study. The patients were divided into six similar groups, each one tested with one of the six lenses included in the study. RESULTS: Changes at the values of high order aberrations were verified during the use of contact lenses. In 78 (60 percent) of the 130 analyzed eyes an increase at the RMS (rooth mean square) values during the use of contact lens was detected. All types of analyzed contact lenses showed an increase of "coma" aberrations due to contact lens use. Frequency® Aspheric and Cooperflex® had the best visual performance in relation to "coma". There was a decrease in the medium value of spherical aberrations during the use of contact lenses, higher in myopic patients than in the hyperopic. There was an increase in the other high order aberrations (that exclude the third order "coma" and fourth order spherical aberration) characterized by the component "others" on the aberrometry examination. Focus® Choice AB had the best visual performance of this component. CONCLUSION: The use of soft contact lenses modifies the performance of high order aberrations, showing an increase of the medium values of asymmetric Zernike aberrations. This was not observed for symmetric spherical aberrations. No statistically significant differences were observed between the performance of six kinds of...

Diamond burr superficial keratectomy in the treatment of visually-significant anterior corneal lesions / Ceratectomia superficial com broca de diamante no tratamento de lesões anteriores da córnea

PURPOSE: To evaluate the efficacy and safety of diamond burr superficial keratectomy in the treatment of visually-significant anterior corneal lesions. METHODS: A retrospective review of 23 eyes (23 patients). Pre- and postoperative visual acuities and refractions, slit-lamp biomicroscopic findings, and the incidence of recurrence of disease after keratectomy were studied. RESULTS: Nineteen eyes had map-dot-fingerprint basement membrane dystrophy and 4 had Salzmann's nodular degeneration. All patients presented with decreased vision, as well as varying degrees of glare, halos, and monocular diplopia. Postoperative follow-up ranged from 3 to 39 months (mean 10.6 months), and no recurrence of the original disease occurred within this period. This procedure improved the best-corrected visual acuity from 20/36 (LogMar 0.250) to 20/24 (LogMar 0.076) by LogMar statistical evaluation (p<0.001) and caused a statistically non-significant (p=0.232) myopic change in the mean refractive spherical equivalent (-0.36 diopter ± SD 2.28 preoperatively to -0.71 ± 2.26 postoperatively). Glare and monocular diplopia were subjectively reduced or eliminated in all patients. One patient had mild anterior stromal haze which decreased the bestcorrected visual acuity from 20/25 to 20/30. CONCLUSION: Diamond burr superficial keratectomy appears to be an effective and safe method of removing visually-significant anterior corneal opacities.

OBJETIVO: Avaliar a eficácia e segurança da ceratectomia superficial com broca de diamante no tratamento das lesões anteriores da córnea. MÉTODOS: Foi realizado estudo retrospectivo de 23 olhos de 23 pacientes. Foram avaliados acuidade visual e refração pré e pós-operatório, biomicroscopia e incidência de recorrência da doença após ceratectomia. RESULTADOS: Dos 23 olhos avaliados, 19 olhos apresentavam distrofia da membrana basal (map-dot-fingerprint) e 4 degeneração nodular de Salzmann. Todos os pacientes apresentavam diminuição da acuidade visual, assim como graus variados de ofuscamento, halos e diplopia monocular. O seguimento pós-operatório variou entre 3 e 39 meses (média de 10,6 meses) e não houve recorrência da doença original nesse período. O procedimento melhorou a acuidade visual com melhor correção de 20/36 (LogMar 0,250) para 20/24 (LogMar 0,076) com p<0,001. Em relação as mudanças refracionais não houve significância (p=0,232) sendo o equivalente esférico pré-operatório de - 0,36 ± 2,28DE e pós-operatório de -0,71 ± 2,26DE. As queixas de ofuscamento e diplopia monocular diminuíram ou foram eliminadas em todos os pacientes. Apenas 1 paciente apresentou nubécula no estroma anterior com diminuição da acuidade visual com melhor correção de 20/25 para 20/30. CONCLUSÃO: Ceratectomia superficial com broca de diamante parece ser método efetivo e seguro para remover opacidades anteriores de córnea.

The Effects of Optic Disc Factors on Retinal Nerve Fiber Layer Thickness Measurement in Children

PURPOSE: We analyzed the effect of the changes of the optic disc area (ODA) caused by the axial length and the refractive error, and the consequent changes of the distance from the optic disc margin to the circular scan (OD-CS) of Optical coherence tomography (OCT) on the measurement of the retinal nerve fiber layer thickness(RNFLT) were examined. METHODS: One hundred two eyes of 51 children (age range 4 to 15 years) were measured using OCT including the RNFLT. For the ODA and the OD-CS, the relative area formed by the ODA and the circular scan was obtained. In addition, the correlation of the refractive error and the axial length to the optic disc factors was assessed. RESULTS: As hyperopia progresses to myopia, the axial length became longer, the ODA became smaller (r=-0.442, p=0.000) and the OD-CS showed a tendency to increase (r=0.471, p=0.000). As the OD-CS became longer, the measured average RNFLT decreased significantly (r=-0.248, p=0.012), and the ODA and the OD-CS showed a significant correlation to the RNFL thickness that was measured in the nasal and inferior areas, the S2, N2 and N3 areas and the I1 area. CONCLUSIONS: As ODA becomes smaller and the OD-CS becomes longer, the RNFLT measured in the nasal and inferior areas, the S2, N2, N3, I1 area has a tendency to be thinner. Hence, consideration of the disc area is required when interpreting the RNFLT of these eyes.

Comparison between Anterior Corneal Aberration and Ocular Aberration in Laser Refractive Surgery

PURPOSE: To compare changes of anterior corneal aberration (Pentacam(R)) and ocular aberration (aberrometer, LADARWave(R)) after laser refractive surgery. METHODS: Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam(R) and an aberrometer (LADARWave(R)) respectively. Changes of root mean square (RMS) values of coma, spherical aberration, and total high order aberration (HOA) were evaluated before, 1 month, and 3 months after surgery RESULTS: Ocular aberrations displayed low preoperative values, but after laser refractive surgery, anterior corneal aberration and ocular aberration increased equally. There were no statistically significant differences of internal optics aberration values (ocular aberration minus anterior corneal aberration) in coma, spherical aberration, and total HOA. Anterior corneal aberration and ocular aberration showed statistically significant correlations at 1 and 3 months after surgery. CONCLUSIONS: Internal optics aberration compensated the anterior corneal aberration effectively before surgery, but the increase of anterior corneal aberration after laser refractive surgery exceeded the compensation of internal optics. As a result, anterior corneal aberration and ocular aberration increased equally. The correlation between anterior corneal aberration and ocular aberration after surgery was statistically significant due to the increased proportion of anterior corneal aberration in ocular aberration.

Simulação computacional de cirurgias foto-refrativas personalizadas e precisão relacionada à ordem das aberrações ópticas / Computational simulation of customized photorefractive surgery and precision of correction related to different order aberrations

O objetivo principal deste trabalho foi o desenvolvimento e a implementação de um algoritmo para simulação de cirurgias foto-refrativas. Sabe-se que os atuais " flying-spot" lasers para cirurgia refrativa disponíveis no mercado ainda contêm limitações na correção de algumas aberrações de ordem alta. No entanto, há muito pouca informação quantitativa sobre os erros envolvidos em função da complexidade das aberrações. Aplicando-se superfícies objetivo descritas por uma série de coeficientes de Zernike e o conceito matemático de convolução, várias ablações personalizadas foram simuladas para várias aberrações, desde baixa ordem (esfero-cilíndricas) até aberrações de décima ordem (como coma, aberração esférica, entre outras). Os resultados mostram que o perfil de ablação de cada pulso do laser assim como seu diâmetro são fatores críticos quando o objetivo é corrigir aberrações de alta ordem. Além disso, outras conclusões foram possíveis, como por exemplo a de que nem todas as aberrações de alta ordem induzem aos mesmos erros na ablação. Também foi possível verificar que a correção de aberrações de alta ordem nos termos radiais (como aberração esférica) é bem mais difícil do que naqueles termos contendo alta frequência angular (como trefoil).

PURPOSE: To develop and implement an algorithm for simulation of photorefractive surgery. It is well known that many flying-spot lasers in the market have limitations in correcting higher order aberrations, but there is little quantitative information about errors related to aberration complexity. METHODS: By applying known surfaces described by Zernike polynomials of different orders it was possible to simulate several target surfaces that may well resemble in vivo cases of refractive surgery candidates. An algorithm that uses the mathematical concept of convolution was implemented and several simulated surfaces were tested, ranging from low order aberrations (sphere-cylinder) to 10th order aberrations, (high orders of coma, spherical aberration, trefoil, etc). RESULTS: the results show that the laser profile and diameter are critical factors when considering the correction of higher order aberrations. CONCLUSIONS: Not all aberrations of the same high order induce the same amount of error - spherical aberrations are shown to be far more difficult to correct than higher order aberrations related to angular frequency.

Avaliação de lente intra-ocular fácica para a correção da presbiopia / Phakic intraocular lens for presbyopia correction

OBJETIVO: Avaliar os resultados clínicos e refrativos, bem como as complicações pós-operatórias, da cirurgia de implante de uma lente fácica multifocal de suporte angular para a correção da presbiopia. MÉTODOS: Estudo retrospectivo de análise de prontuários de 30 pacientes dos quais 51 olhos foram submetidos a implante de lente intra-ocular fácica Newlife® para a correção da presbiopia. Os pacientes foram avaliados em visita pré-operatória e em um mês, 3, 6 e 12 meses após a cirurgia. A análise descritiva das variáveis do estudo e os testes estatísticos foram realizados e as complicações pós-operatórias foram descritas. RESULTADOS: Após o procedimento, o equivalente esférico médio foi de -0,046 (± 0,48 D) e 87,5 por cento dos pacientes podiam ler P3 (equivalente a J2) sem necessidade de óculos. A perda de células endoteliais, após seguimento de 12 meses, foi de 7,57 por cento. A lente intra-ocular foi retirada em 6 (11,5 por cento) olhos por diferentes razões, sendo a catarata a causa mais freqüente de retirada de lente. CONCLUSÕES: O implante da lente intra-ocular fácica Newlife® para a correção da presbiopia melhorou significativamente a acuidade visual sem correção e a refratometria no grupo de olhos estudados. Os critérios de avaliação adotados (acuidade visual com correção, contagem endotelial e existência de complicações) não permitiram afirmar a segurança do procedimento de implante da lente intra-ocular fácica Newlife® para o período de acompanhamento analisado.

PURPOSE: To evaluate clinical and refractive results of anterior chamber multifocal phakic intraocular lens Newlife® for presbyopia correction considering uncorrected far and near visual acuity and refraction data and also to evaluate safety of this intraocular lens considering distance and near corrected visual acuity, endothelial cell count and complications. METHODS: Retrospective analysis of a clinical database of 30 patients (51 eyes) who had received a foldable anterior chamber multifocal intraocular lens for presbyopia correction. Data were collected before surgery and at 1, 3, 6, 12 months after the procedure. Statistical variance analysis and multiple comparisons were used to verify possible associations. All complications were described. RESULTS: After surgery the mean spherical equivalent was -0.046 D (+/-0.48) and 87.5 percent of the eyes could read Parinaud 3 or better (equivalent to J2 or better) without the need of near glasses. Endothelial cell loss was 7.57 percent. The intraocular lens was explanted in 6 (11.5 percent) eyes for different reasons. Cataracts were the major cause of lens removal. CONCLUSION: Improvement of mean uncorrected visual acuity and refraction data after multifocal phakic intraocular lens Newlife® implantation for presbyopia correction was observed. Established safety criteria (distance and near corrected visual acuity, endothelial cell count and complications) did not confirm the safety of the procedure in the follow-up period.

Aberrações de alta ordem: associação com a idade e erros de refração / Relationship between high-order aberrations and age and between high-order aberrations and refraction errors

OBJETIVO: Avaliar a relação entre aberrações de alta ordem e erros de refração e a relação entre aberrações de alta ordem e a idade. MÉTODOS: Realizou-se estudo retrospectivo analítico, de pacientes submetidos a exames de aberrometria. Foram incluídos neste estudo todos os indivíduos examinados com aberrômetro LadarWave® (Alcon, Fort Worth, Texas), no Hospital de Olhos do Paraná (Curitiba - Paraná) no período de abril de 2004 a abril de 2005, sendo o principal critério de inclusão acuidade visual corrigida ou não de 20/20 ou melhor e o principal critério de exclusão presença de cirurgia e/ou doença ocular prévia. Foram estudadas as seguintes variáveis: idade, grau de refração esféro-cilíndrica, medida do equivalente esférico, aberrações de alta ordem divididas em: coma, aberração esférica, outras e "root mean square" (RMS) de alta ordem. Todas as variáveis foram obtidas com exame de aberrometria realizado no aberrômetro LadarWave®, sob cicloplegia, considerando-se pupila de 6,5 mm. Foram avaliadas aberrações ópticas de alta ordem até a oitava ordem nos polinômios de Zernike. Os pacientes foram divididos em 6 grupos de acordo com o vício de refração e em 3 grupos de acordo com a idade. RESULTADOS: Foram avaliados no período estudado 312 olhos dos quais 201 foram incluídos no estudo. A idade média desses pacientes foi de 33,9 ± 10,1 anos variando de 7 a 62 anos. Na comparação geral entre os grupos de acordo com o vício de refração, foi observado que os pacientes hipermétropes com astigmatismo inferior a -0,75 D (Grupo 5) apresentaram maior quantidade de aberração esférica, e que os pacientes hipermétropes com astigmatismo superior a -0,75 D (Grupo 6) apresentaram maior quantidade de aberrações denominadas "outras" e RMS de alta ordem. Na comparação geral entre os grupos de idade, em relação as variáveis estudadas, o grupo de pacientes com 45 ou mais anos (Grupo C) apresentou maior quantidade de todas as aberrações estudadas. CONCLUSÕES:...

PURPOSE: To evaluate the relationship between high-order aberrations and refractive errors, and between high-order aberrations and age. METHODS: An analytic retrospective study of patients that underwent aberrometry examination was conducted. All subjects examined with LadarWave® aberrometer at the Hospital de Olhos do Paraná from April 2004 to April 2005 were included in this study. The major inclusion criterion was 20/20 or better - corrected or not - visual acuity; and the major exclusion criterion, the presence of previous eye surgery or disease. The following variables were analyzed: age, refraction, spherical equivalent, and high-order aberrations wich were: coma, spherical aberration, others, and high-order root mean square (RMS). All data were obtained by LadarWave® aberrometry examination, under cycloplegia, utilizing only 6.5 mm pupil results. High-order aberrations up to eight order Zernike's coefficients were evaluated. Patients were divided into 6 groups according to refraction error and into 3 groups according to age. RESULTS: Two hundred and one of 312 eyes were studied. The mean age was 33.9 ± 10.1, varying from 7 to 62 years of age. Among the refraction error groups hyperopic patients with less than -0.75 D astigmatism (Group 5) showed a higher amount of spherical aberration, and hyperopic patients with more than -0.75 D astigmatism (Group 6) showed a higher amount of other and high-order RMS aberrations. In the general comparison between the age groups, the 45 or older group (Group C) showed a higher amount of all the analyzed aberrations. CONCLUSION: a) There was a statistically significant positive relationship between hyperopia - with or without astigmatism - and spherical aberration and high-order RMS. b) There was a statistically significant positive relationship between age and all analyzed aberrations.

Randot stereoacuity at various binocular combinations of Snellen acuity.

Binocular combinations of Snellen acuity were varied from 6/60 to 6/6 in standard steps in twenty normal adults and Randot stereoacuity was measured at each level. Using the 560 unique stereoacuity scores thus obtained, a nomogram was constructed which provides expected stereoacuity scores at all unique binocular combinations of Snellen acuity. It was seen that there is a linear correlation between binocular isoacuity (at level 6/36 or better) and Randot stereoacuity.

Espessura corneana na alta miopia / Corneal thickness in high myopia

Propósito: Avaliar a espessura corneana em portadores de alta miopia. Método: Quarenta e seis olhos de 25 portadores de alta miopia (Grupo I, de -9,0 D a-25,0 D) foram avaliados através da paquimetria ultrassônica para se determinar a espessura corneana nas regiöes central(C), nasl inferior (NI) e superior (NS) e temporal inferior (TI) e superior (TS). Três medidas paquimétricas foram obtidas em cada uma das regiöes estudadas. Noventa olhos de 45 indivíduos emétropes ou portadores de baixa de baixa ametropias (Grupo II, -3,7 D a +3,2 D)foram avaliados conforme o Grupo II e os resultados de ambos comparados segundo o teste de Mann-Whitney. Resultados: A paquimetria média em micras (+/- DP) de todas as regiöes estudadas foi de 563,5 +/- 29,9 e de 581,1 +/- 32,9 respectivamente nos grupos I e II (P=0,004). A paquimetria média em cada uma das regiöes estudadas foi de 512,4 + 39,6 (C), 564,8 +/- 42,4 (NI), 578, 4 +/- 43,2 (NS), 572,7+/- 51,3 (TI) e 589,1 +/- 46,0 (TS) e e 523,3 +/- 34,6 (C), 587,8 +/- 41,5 (NI), 603,4 +/- 46,0 (NS), 591,0 +/- 41,3 (TI) e 600,0 +/- 45,1 (TS) respectivamente para os Grupos I e II. Os quadrantes inferiores das córneas em ambos os grupos apresentaram-se menos espessos em pelo menos 70 por cento das medidas, predominantemente o NI. Os quadrantes NI, NS e TI apresentaram medidas estatisticamente menpores no Grupo I em relaçäo ao Grupo II. Conclusäo: De acordo com os resultados obtidos acima, indivíduos altos míopes parecem apresentar córneas menor espessas do que os emétropes ou portadores de baixas ametropias.

Estudo da acuidade visual em crianças portadoras de toxoplasmose ocular congênita / Study of visual acuity in carriers children of congenital ocular toxoplasmosis

A toxoplasmose ocular congênita causa lesöes maculares que provocam uma perda vidual severa. com o objetivo de analisar a resposta visual de crianças portadoras desta doença, a acuidade visual por resoluçäo de grade de estímulos foi obtida pelo método dos cartöes de acuidade de Teller em 37 indivíduos de 9 a 156 meses de idade, com lesöes retínicas maculares bilateraiscicatrizadas pertencentes ao ambulatório de visäo subnormal do departamento de Oftalmologia dae Santa Casa de Säo Paulo. Em 18 pacientes com idade superior a 48 meses os resultados obtidos foram comparados à acuidade visual por reconhecimento de optotipos.