Correlation between visual function and refractive, topographic, pachymetric and aberrometric data in eyes with keratoconus.

AIM: To analyze the relationship between two visual functions and refractive, topographic, pachymetric and aberrometric indicators in eyes with keratoconus. METHODS: Corrected distance visual acuity (CDVA), and letter contrast sensitivity (CS) were correlated with refraction, corneal topography, pachymetry, and total corneal wavefront data prospectively in 71 eyes with keratoconus. The topographic indices assessed were simulated keratometry for the flattest and steepest meridians (SimK1 and SimK2), posterior steeper K (Ks), elevation value in best-fit sphere (BFS) maps, squared eccentricity (Є(2)), aspheric asymmetric index (AAI), pachymetry, thickness progression index (TPI), the amount of pachymetric decentralization (APD), and GalileiTM-keratoconus indices. RESULTS: The mean CDVA (expressed as logMAR) were 0.25±0.21. The mean CS was 1.25±0.46. The spherical refraction correlated well with CDVA (r=-0.526, P<0.001). From topographic indices, SRI correlated with CS (r=-0.695), and IAI with CS (r=-0.672) (P<0.001 for all). Root mean square (RMS) was 4.3±1.81 µm, spherical aberration (SA) was -0.4±0.67 µm, vertical and horizontal coma were -2.1±1.47 and -0.4±0.72 µm. All wavefront data (except horizontal coma), AAI, Є(2) and maximum BFS correlated significantly with the visual function (P≤0.001 for all). CONCLUSION: In this study, CS is more affected than CDVA as a visual function. The quantity and quality of vision is significantly correlated with well-known and new topographic indices. There is not a significant correlation between visual function and pachymetric parameters. The significantly correlated indices can be used in staging keratoconus and to follow the outcome of a treatment.

Orbscan II and double-K method for IOL calculation after refractive surgery.

BACKGROUND: Precise IOL calculation in post-refractive surgery patients is still a challenge for the cataract surgeon. The purpose of this study is to test whether adding Orbscan II values into the double-K method improves IOL calculation in this group of patients. METHODS: A prospective study with 43 eyes previously submitted to refractive surgery that underwent cataract extraction. IOL calculation was performed with double-K method. Post-K value was derived from Orbscan total-mean power map. The average corneal curvature of the general population (43.8D) was used as the pre-K value. Refraction results 30 days after surgery were compared with refraction that would be obtained if we used: (1) post-K values from keratometry, (2) post-K values from topography, and (3) pre-K values from Orbscan total-mean power. Anterior chamber depth measures obtained with the IOL Master and Orbscan II were compared. RESULTS: Mean postoperative spherical equivalent (SE) was -0.25 ± 1.10 D in eyes submitted to radial keratotomy , -1.04 ± 1.42 D in eyes previously submitted to myopic Lasik, and +0.05 ± 1.76 D in those submitted to hyperopic surgeries. Had we inputted post-K values derived from keratometer and from topography, we would have obtained significantly higher postoperative refractive errors in eyes previously submitted to myopic refractive surgery (p < 0.05). Refractions using pre-K derived from the central 8 mm Orbscan instead of 43.8 D were similar in all studied groups (p > 0.05). Anterior chamber depth measured with IOL Master or Orbscan were similar. CONCLUSIONS: Orbscan measurements used as the post-K values into the double-K method provide a precise IOL calculation, especially in post myopic refractive surgery patients.

Calculation of intraocular lens power using Orbscan II quantitative area topography after corneal refractive surgery.

PURPOSE: To present the prospective application of the Orbscan II central 2-mm total-mean corneal power obtained by quantitative area topography in intraocular lens (IOL) calculation after refractive surgery. METHODS: Calculated and achieved refraction and the difference between them were studied in 77 eyes of 61 patients with previous radial keratotomy (RK), RK and additional surgeries, myopic LASIK, myopic photorefractive keratectomy (PRK), or hyperopic LASIK who underwent phacoemulsification without complications in 3 eye centers. All IOL calculations used the average from the central 2-mm Orbscan II total-mean power of maps centered on the pupil without the use of previous refractive data. Six IOL styles implanted within the bag were used. RESULTS: Using the SRK-T formula, the overall calculated refraction was -0.64+/-0.93 diopters (D). The overall achieved spherical equivalent refraction (-0.52+/-0.79 D; range: -3.12 to 1.25 D; 95% confidence interval [CI]: -0.70/-0.34 D) was +/-0.50 D in 53% of eyes, +/-1.00 D in 78% of eyes, and +/-2.00 D in 99% of eyes. The overall difference between the calculated and achieved refraction (0.12+/-0.93 D, P=.27; range: -2.18 to 2.62 D; 95% CI: 0.09/0.33 D) was +/-0.50 D in 39% of eyes, +/-1.00 D in 77% of eyes, and +/-2.00 D in 96% of eyes. This difference was +/-1.00 D in 77% of eyes with RK (P=.70), 82% of eyes with myopic LASIK (P=.34), and 90% of eyes with myopic PRK (P=.96). In eyes with RK followed by LASIK, a trend toward undercorrection was noted (P=.03). In eyes with hyperopic LASIK, a trend toward overcorrection was noted (P=.005). CONCLUSIONS: In eyes with previous corneal refractive surgery, IOL power calculation can be performed with reasonable accuracy using the Orbscan II central 2-mm total-mean power. This method had better outcomes in eyes with previous RK, myopic LASIK, and myopic PRK than in eyes with hyperopic LASIK or RK with LASIK.

Sectorial and annular quantitative area pachymetry with the Orbscan II.

PURPOSE: To present a new application of quantitative area pachymetry of the cornea. METHODS: Sectorial quantitative area pachymetry of small corneal zones located at the center and surrounding areas is possible by means of the statistical analysis device and tools menu of Orbscan II (Bausch and Lomb). RESULTS: Average pachymetry of 1 central zone and 12 small zones around the center may be shown in the pachymetry map by simply formatting the system. Average pachymetry, standard deviation, rate of thickness variation (slope), and volume of analyzed annular corneal zone can also be automatically shown in a data window. The examination results can be printed and kept on record. CONCLUSIONS: The method is simple and descriptive. This type of preoperative evaluation may guide the manual or laser preparation of channels for intracorneal segments and the corneal trephination for lamellar or penetrating keratoplasty.

Comunicação visual por computador na esclerose lateral amiotrófica / Computerized visual communication in amyotrophic lateral sclerosis

OBJETIVO: Descrever os sistemas eletrônicos de comunicação utilizados por um paciente com esclerose lateral amiotrófica (ELA) e a doença oftal-mológica apresentada por um grupo de pacientes gravemente incapacitados. A partir deste relato, revisamos as manifestações oftalmológicas da esclerose lateral amiotrófica, os sistemas de comunicação não convencionais e a importância do atendimento domiciliar e da comunicação no tratamento destes pacientes. MÉTODOS: Relato de casos clínicos, descrição de equipamento e revisão da literatura. RESULTADOS: O paciente com esclerose lateral amiotrófica apresentou sintomas de origem bulbar, comprometimento da musculatura respiratória e dos membros, com musculatura ocular extrínseca parcialmente poupada, intelecto e estado de consciência intactos. Utilizando a mobilidade facial e a ocular, equipamento eletrônico e computador, ele conseguiu comunicar-se e trabalhar como desenhista gráfico. Atualmente, o tratamento paliativo recomendado para pacientes crônicos acamados é prestado por equipes multi-profissionais como a Assistência Domiciliar da Unimed-Campinas (ADUC). A doença oftalmológica encontrada neles é diversa. CONCLUSÕES: A esclerose lateral amiotrófica, assim como outras doenças crônicas podem deteriorar drasticamente a qualidade de vida. O seu tratamento e planejamento de custos de longo prazo devem proporcionar a maior autonomia possível, boa comunicação e meio ambiente digno e adequado, visando à saúde física e psicológica dos pacientes e a de seus familiares. O oftalmologista deve estar preparado para formar parte deste atendimento. Medidas simples, como piscar diante uma cartela, ou sofisticadas, como usar computador, são úteis e possibilitaram a "comunicação visual" dos pacientes, isto é, a expressão de idéias e pensamentos mediante os olhos e as pálpebras.

A direct method to measure the power of the central cornea after myopic laser in situ keratomileusis.

OBJECTIVE: To measure the corneal power after myopic laser in situ keratomileusis (LASIK). METHODS: Six central areas in 6 corneal power maps were studied using the Orbscan II statistical analysis device in 26 eyes that underwent myopic LASIK. Refractive and corneal power changes were compared. Factors related to wrong corneal power measurement were evaluated. MAIN OUTCOME MEASURES: Cycloplegic refraction, refractive change at the corneal plane, and Orbscan II corneal power maps. RESULTS: Preoperatively, only posterior-mean power (P<<.001) and anterior-posterior power ratio (P<<.001) varied according to the size of the analyzed area. Postoperatively, total-optical (P =.03), keratometric-mean (P =.04), total-mean (P<.001), anterior-mean (P =.03), and posterior-mean (P<<.001) powers; and anterior-posterior power ratio (P<<.001) varied according to the area. Postoperatively, the difference between keratometric-mean and total-mean powers became larger (P<.001), and the anterior-posterior power ratio was reduced (P<<.001). A posterior-mean power change occurred (P =.04). Refractive change after myopic LASIK was best estimated by 2-mm total-mean power (mean +/- SD difference, 0.07 +/- 0.62 diopters [D]; P =.55) and 4-mm total-optical power (mean +/- SD difference, -0.08 +/- 0.53 D; P =.37). CONCLUSIONS: Total corneal power is more positive and refractive change is underestimated when deduced from the anterior surface radius and keratometric refractive index. The anterior-posterior power ratio is not a fixed value. The best area to estimate the refractive change depends on the method used to obtain the power in diopters. Refractive change tended to be underestimated in larger areas and higher preoperative myopia. Orbscan II total-mean and total-optical power maps accurately assess the corneal power after myopic LASIK independent of preoperative data or correcting factors, and should improve intraocular lens calculation.

A model for the natural history of retinoblastoma according to its cellular differentiation

Objetivo: Estudar a correlação entre a diferenciação celular do retinoblastoma, sua origem genética, estadiamento, idade do paciente e demora no tratamento. Métodos: O padrão histopatológico de 282 casos (271 pacientes) com retinoblastoma intra-ocular e extra-ocular enucleados (como primeiro tratamento) foi retrospectivamente revisado. Os casos bem diferenciados tiveram rosetas de Flexner-Wintersteiner e Homer-Wright, os pouco diferenciados somente rosetas de Homer-Wright e os indiferenciados nenhuma roseta. Os hereditários germinais tiveram história familiar ou apresentação bilateral-multifocal. O não hereditários-esporádicos foram unilaterais. Foram realizadas análises multifactoriais com os testes Chi2, G e Kruskal-Wallis. Resultados: Houve 116 (41 por dento) casos germinais, 166 (59 por cento) esporádicos; 184 (65 por cento) intra-oculares, 94 (33 por cento) extra-oculares; 59 (21 por cento) bem diferenciados, 55 (20 por cento) pouco diferenciados, 141 (50 por cento) indiferenciados. Origem, estadiamento e diferenciação celular foram dependentes entre si (p<0,0001). A probabilidade de encontrar rosetas Flexner-Wintersteiner foi maior nos germinais (p<0,0001) e nos intra-oculares (p<0,001). A idade média dos primeiros sinais (8,66 meses, p<0,0001) e da enucleação (14,02 meses, p<0,0001) foi menor nos bem diferenciados que nos indiferenciados (22,66 e 32,81 meses, respectivamente). Os bem diferenciados (5,7 meses) foram tratados antes (p=0,0089) que os indiferenciados (9,87 meses). Antes dos seis meses de idade, 75 por cento dos casos foram bem diferenciados, (p<0,0001). Após os três anos, 75 por cento foram indiferenciados. Conclusão: O padrão bem diferenciado é mais frequente nas crianças mais novas, nos casos hereditários e nos intra-oculares. O indiferenciado predomina nos mais velhos, nos esporádicos e nos extra-oculares. Na evolução do RB aconteceria uma transformação fenotípica tumoral que influenciaria a frequência dos padrões clinico-histopatológico encontrados às diferentes idades.

O cálculo do poder das lentes intra-oculares e o Orbscan-II. Parte 1: O poder óptico da córnea normal / Power calculation of intraocular lenses and the Orbscan-II. Part 1: The power of the normal cornea

OBJETIVO: Avaliar o poder dióptrico da porção central da córnea normal. MÉTODOS: Análise retrospectiva da topografia por varredura de fenda de luz e disco de Plácido em 30 olhos normais. RESULTADOS: Os poderes médios ceratométrico, anterior, da espessura e total; ópticos ceratométrico e total; axiais ceratométrico e total; tangencial total, equivalente e a soma do poder médio de ambas superfícies foram semelhantes (p>0,8361) nas quatro áreas centrais analisadas (0,04, 1, 3 e 5 mm de diâmetro). O poder médio posterior diminuiu de -6,62 D até -6,35 D (p=0,0030). A espessura média aumentou de 524 æm até 554 æm (p=0,0231), representando 0,13 D do poder total da córnea. Os poderes óptico (p<0,0167), axial (p<0,0099) e médio (p<0,0030) ceratométricos foram aproximadamente 1,50 D mais positivos que os respectivos poderes totais. O poder médio total foi igual ao poder equivalente (p>0,4907) e à soma do poder de ambas superfícies (p>0,3868). O poder médio anterior foi ao redor de 7,5 vezes maior que o poder médio posterior. CONCLUSÕES: O poder real da córnea calculado usando ambas superfícies, sua espessura e os índices de refração fisiológicos é menor que o poder convencionalmente aceito e determinado pela medição da curvatura da superfície anterior e o índice de refração ceratométrico da córnea (F

Orientaçöes para o polimento e retoque das lentes de contato rígidas gás permeáveis / Basic instructions on polishing and finishing rigid gtas permeable contact lenses

Objetivo: Relatar, passo a passo, orientaçöes básicas de polimento e retoque de lentes de contato rígidas gás permeáveis (RGP). Métodos: Com uma unidade de retoque pode polir-se adequadamente as superfícies de lentes RGP e modificar-se bordas, espessura e curvatura periféricas, diâmetro e poder óptico. Conclusöes: Os procedimentos recomendados servem para restabelecer a qualidade de lentes deterioradas, prolongar seu tempo de vida ou melhorar o conforto e as condiçöes de adaptaçäo nos pacientes que usam este tipo de correçäo