Renata Siqueira da Silva

Central corneal thickness and biomechanical changes after clear corneal phacoemulsification.

PURPOSE To evaluate central corneal thickness (CCT) and ocular biomechanical properties in patients before and after clear corneal phacoemulsification. METHODS Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), and Goldmann-correlated IOP (IOPg) were measured with the Ocular Response Analyzer (ORA; Reichert Ophthalmic Instruments) in 36 consecutive patients (47 eyes) who underwent clear corneal phacoemulsification. Central corneal thickness was measured with the Pentacam (Oculus Optikgeräte GmbH). All measurements were performed prior to surgery and at follow-up at 1, 7, and 30 days postoperatively. RESULTS Central corneal thickness was higher at 1 and 7 days compared to preoperatively (P<.05) but not at 30 days. Corneal hysteresis was lower at 1 day than preoperatively (P<.05) but not at 7 and 30 days. Corneal resistance factor was lower at 1, 7, and 30 days compared to preoperatively (P<.05). Corneal-compensated IOP was slightly lower at 1, 7, and 30 days compared to preoperatively, but was not statistically significant (P>.05). Goldmann-correlated IOP was statistically significantly lower at 1 and 7 days than preoperatively (P<.05). CONCLUSIONS Clear corneal phacoemulsification led to a change in ocular biomechanical properties. The increase in CCT after phacoemulsification was followed by a reduction in CRF and CH. Mean IOPcc was similar before and after phacoemulsification, indicating that IOPcc may be a more accurate indicator of true IOP than IOPg.

Impact of the wavefront analysis in refraction of keratoconus patients

OBJETIVO: Verificar se a aberrometria ocular total (analise da frente de onda ou wavefront) possibilita a melhora na acuidade visual corrigida (AVc) com lentes esfero-cilindricas, obtida com a refratometria manifesta em casos de ceratocone com algum grau de intolerância ao uso de lentes de contato. METODOS: Os prontuarios de 46 pacientes (89 olhos) referidos com diagnostico de ceratocone e intolerantes ao uso de lentes de contato, submetidos ao exame de aberrometria ocular total seguido de refracao manifesta, foram estudados de forma retrospectiva. A AVc (logMAR) com a correcao existente antes do exame foi comparada com a obtida com a nova refracao manifesta, realizada, considerando-se os dados objetivos da aberrometria. O teste nao-parametrico de Wilcoxon para amostras pareadas foi utilizado para verificacao de diferencas estatisticamente significantes na AVc. RESULTADOS: Houve uma melhora estatisticamente significante na AVc com a nova refracao manifesta (p OBJECTIVE: To verify if the total ocular aberrometry (wavefront analysis) facilitates manifest refraction and improvement in best spectacle distance corrected visual acuity (BSCDVA) with sphero-cylindrical lenses, in keratoconus cases with some degree of contact lenses intolerance. METHODS: Retrospective chart review of 46 patients (89 eyes) referred with keratoconus and contact lenses intolerance was performed. Ocular aberrometry with ray tracing was followed by manifest refraction. BSCDVA (logMAR) with the previous correction was compared with the one obtained based on the wavefront auto-refraction. The nonparametric test of Wilcoxon for paired samples was used to test statistically significant differences in BSCDVA. RESULTS: There was a statistically significant improvement in BSCDVA with the new manifest refraction (p

Avaliação da pressão intraocular através do ocular response analyzer antes e após cirurgia de facoemulsificação

OBJETIVO: Verificar a variacao das medidas pressoricas atraves do Ocular Response Analyzer (ORA, Reichert): IOPg (gold standard, Goldmann correlated intraocular pressure) e IOPcc (corneal compensated intraocular pressure) antes e apos a cirurgia de catarata por facoemulsificacao. METODOS: Estudo observacional prospectivo envolvendo 47 olhos de 36 pacientes que se submeteram a cirurgia de catarata por facoemulsificacao com implante de lente intraocular. A Pressao intraocular compensada da cornea (IOPcc) e correlacionada com Goldmann (IOPg), foram medidos pelo Ocular Response Analyzer (ORA); As medidas foram realizadas no pre-operatorio, 1o dia e 30o dia apos a cirurgia de facoemulsificacao. O Teste de Kolmogorov-Smirnov foi utilizado para avaliar a distribuicao normal. Diferencas obtidas entre as medidas obtidas atraves do Ocular Response Analyzer foram avaliadas pelo T-test (Students paired t-test). Foi considerado como estatisticamente significante p < 0,05%. RESULTADOS: As medias da IOPcc no pre-operatorio, no primeiro dia e no trigesimo dia apos a cirurgia de facoemulsificacao e implante de LIO foram de 15.6 (±3.06), 15.5 (±3.14) , e 15.71 (±4.34). A media de IOPg no pre-operatorio foi de 14.7 (± 3.0), no primeiro dia apos cirurgia 12.9 (± 3.1) e no trigesimo dia 13.4 (± 3.7). Houve diferenca significativa entre IOPg (PRE X D1) com p < 0,01. CONCLUSAO: Observamos uma diminuicao da IOPg no pos-operatorio imediato em corneas com edema apos facoemulsificacao. Logo, ressaltamos a importância da biomecânica na medida da Pio.

The need for artificial tears in glaucoma patients: a comparative, retrospective study

PURPOSE To evaluate the need for artificial tears by glaucoma patients under topical hypotensive treatment and to identify risk factors associated with it. METHODS The charts of 175 glaucoma patients under medical treatment and 175 age-matched controls were reviewed. Age, gender, use of artificial tears, number of glaucoma medications used, and duration of treatment were recorded. RESULTS Significantly more glaucoma patients (n=92; 52.6%) used artificial tears compared to age-matched controls (n=31; 17.7%) (p<0.001). Significantly more females (n=81; 39%) than males (n=42; 28.9%) used artificial tears (p=0.036). When the whole population was analyzed, female gender (OR=1.63) and the presence of glaucoma (OR= 5.14) were risk factors for the use of artificial tears (p<0.05). When the glaucoma population was analyzed, female gender (OR=2.57), number of medications >2 (OR=1.92), and duration of treatment >5 years (OR=2.93) were risk factors for the use of artificial tears (p<0.05). CONCLUSIONS Topical treatment with antiglaucoma medication is a risk factor for the use of artificial tears. Female gender and long-term treatment of glaucoma with two or more medications were aggravating factors for the need for artificial tears.

Correlações entre a densitometria do cristalino através da imagem de Scheimplufg, tempo e gasto de energia na cirurgia de facoemulsificação

PURPOSE: To evaluate and to correlate the PNS (patient nuclear score) and time and energy (power US) in patients priorto and following phacoemulsification with intraocular lens implantation. METHODS: This is a prospective study. Twenty two consecutive patients (22 eyes) that underwent phacoemulsification surgery and intraocular lens implantation were enrolled. Full ophthalmologic clinical assessment including Pentacam (Oculus, Pentacam) measurements were performed in all cases prior to surgery (Pre). Excluison criteria were corneal disease or scars. RESULTS: There are statistically significant difference between PNS and Time with p < 0,0050 and PNS x Energy with p < 0,0029. CONCLUSION: Preoperatively adjusting phaco parameters based on cataract grade helped improve overall efficiency by reducing the amount of energy and fluid used in the eye and reducing overall phaco time.

Estudo das correlações entre a área do disco óptico e as características geométricas e biomecânicas da córnea

PURPOSE: To correlate optic disc size geometry, corneal architecture and biomechanics. METHODS: Optic disc area and geometry was accessed by HRT III (Heidelberg Retina Tomography - Heidelberg eng), Pentacam (Oculus) was used for accessing IOP and corneal parameters and ORA (Ocular Response Analyze - Reichert) was utilized to access corneal biomechanical properties. Classification based DDLS (Disc Damage Likelihood Scale) scale from retinography was performed. Settings: Instituto de Olhos Renato Ambrosio. RESULTS: 244 eyes of 122 patients (75 female) were included. The average age was 47,2 years (from 8 to 97 years). A significant negative correlation was found between disc optic size and CRF (r=0,1337, p=0,0263). A small trend was also found between optic nerve size and hysteresis (r=-0,1123, p=0,0625). A significant negative correlation was also found between disc optic size and thinnest point, maximal pachymetri progression, corneal volume at (1, 4 e 6mm) and difference from thinnest and central value (p<0,05). The highest negative correlation was with corneal volume within 4mm in diameter (r=-1,887; p=0,0017). A positive correlation between size of optic disc and cornea astigmatism (delta K), was found (r= 1,15; p=0,0129). CONCLUSION: There is a negative correlation between optic disc size and corneal thickness and biomechanical properties. These findings may help explaining susceptibility for the development of glaucoma neuropathy in some cases.

Impacto da análise do "wavefront" na refratometria de pacientes com ceratocone

OBJETIVO: Verificar se a aberrometria ocular total (analise da frente de onda ou wavefront) possibilita a melhora na acuidade visual corrigida (AVc) com lentes esfero-cilindricas, obtida com a refratometria manifesta em casos de ceratocone com algum grau de intolerância ao uso de lentes de contato. METODOS: Os prontuarios de 46 pacientes (89 olhos) referidos com diagnostico de ceratocone e intolerantes ao uso de lentes de contato, submetidos ao exame de aberrometria ocular total seguido de refracao manifesta, foram estudados de forma retrospectiva. A AVc (logMAR) com a correcao existente antes do exame foi comparada com a obtida com a nova refracao manifesta, realizada, considerando-se os dados objetivos da aberrometria. O teste nao-parametrico de Wilcoxon para amostras pareadas foi utilizado para verificacao de diferencas estatisticamente significantes na AVc. RESULTADOS: Houve uma melhora estatisticamente significante na AVc com a nova refracao manifesta (p<0,0001). A AVc media passou de 0,37 ou 20/47 (variando entre 1,3 e 0; desvio padrao[DP]=0,25) com a refracao previa para 0,23 ou 20/34 (variando entre 1 e 0,1; DP=0,21). 52 olhos (58,4%) de 28 pacientes apresentaram melhora na AVc com a nova refracao. A melhora media foi de 0,13 logMAR (1,3 linhas na tabela de Snellen), variando entre nula e 0,6 (6 linhas), com desvio padrao de 0,16. Oito pacientes apresentaram anisometropia significativa que limitou a prescricao de oculos em um dos olhos. CONCLUSAO: A aberrometria facilitou a refratometria, determinando melhora significativa na acuidade visual corrigida com as lentes esfero-cilindricas de pacientes com ceratocone intolerantes ao uso de lentes de contato. A anisometropia foi um fator limitante na prescricao de oculos.

Hipertensão ocular "mascarada" por edema de córnea após cirurgia da catarata

Goldmann applanation tonometry (GAT) overestimates intraocular pressure (IOP) measurements in cases with thick and flatter corneas. This is thought to occur linearly based on mathematical and on experimental studies. However, such influence does exist, but this is more complex than the one anticipated by pachymetry and keratometry because it is related to corneal biomechanical properties. The ocular response analyzer (ORA Reichert) provides the data related to the biomechanical properties of the cornea along with the IOP measurements that are calibrated for correlating to the Goldmann applanation and also compensated from corneal properties. Also corneal tomography with a pachymetric map evaluation characterizes the cornea beyond central thickness and anterior curvature. In this article, we report a case of a 77 years old female patient with low vision, photofobia and ocular pain 28 days after phacoemulsification and intraocular lens implant. In the first visit, GAT was 14mmHg, while IOPcc (ORA corneal compensated IOP) was 25,6mmHg. Corneal hysteresis and resistance factor were low: 4,1 and 6,1mmHg respectively despite a central thickness of 601 micron. Corneal thickness spatial profile was attenuated with an edematous pattern that was also observed by the Scheimpflug images (Pentacam). Hypertensive uveitis was diagnosed and the patient was started on a fixed combination of timolol and brimonidine associate with prednisolone acetate. Three weeks after, the patient referred resolution of photofobia and marked improvement of vision. Clinically, edema was resolved as observed by corneal tomographyc and biomechanical findings.