Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 15 de 15
Filtrar
Mais filtros

Base de dados
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Ophthalmic Genet ; 45(2): 159-163, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37489109

RESUMO

BACKGROUND: Inherited retinopathies can initially present with high refractive error in the first decade of life, before accompanying signs or symptoms are evident. CASE PRESENTATION: A 4-year-old girl with high myopia (S-12.00 C-4.00 × 20 in the right and S-14.50 C-2.75 × 160 in the left eye), moderate visual acuity (0.3 logMAR in the right and 0.4 logMAR in the left eye), and left esotropia, presented with unremarkable past medical history and no family history of high refractive error or low vision. In optical coherence tomography imaging, macular thinning was evident, while morphology was normal. Full-field electroretinogram revealed normal implicit time recordings with reduced amplitudes in scotopic and photopic conditions. Fundus autofluorescence showed a radial pattern in both eyes. During a 5-year follow-up, significant myopia progression ensued (S-17.25 C-3.00 × 20 in the right and S-17.25 C-2.00 × 160 in the left eye), with a corresponding increase in axial length and an unchanged visual acuity. Whole-exome sequencing revealed a heterozygous termination codon variant c.212C>G (p.Ser71Ter) in RPGR, considered to be pathogenic. Segregation analysis precluded the variation in the mother and sister. A random pattern of X-chromosome inactivation was detected in the proband, without X-chromosome inactivation deviation. CONCLUSION: This is the second report associating this specific RPGR mutation with high myopia and the first report to identify it in a female proband. This case provides additional evidence on the genotypic-phenotypic correlation between RPGR c.212C>G mutation and high myopia.


Assuntos
Miopia , Pré-Escolar , Feminino , Humanos , Proteínas do Olho/genética , Heterozigoto , Mutação , Miopia/diagnóstico , Miopia/genética
2.
Clin Exp Ophthalmol ; 40(2): 127-33, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21718405

RESUMO

BACKGROUND: To evaluate the level of agreement between intended and measured ablation of the wavefront optimize profile corrected by the Wellington nomogram in myopic spherocylindrical corrections and assess its impact on refractive outcomes. DESIGN: Prospective, university-institute setting. PARTICIPANTS: Eighty-six participants (86 eyes for photorefractive keratectomy group) and 86 participants (86 eyes for laser in situ keratomileusis group) recruited in a consecutive-if -eligible basis. METHODS: Differences between intended and measured ablation were evaluated with Scheimpflug camera. Refractive outcomes were evaluated by means of postoperative spherical equivalent, postoperative defocus equivalent, contrast sensitivity, correction index, difference vector and index of success. MAIN OUTCOME MEASURES: Correlation of visual outcomes with intended ablation. RESULTS: Both groups demonstrated significant over-ablations (16.7±8.5, P<0.001 & 11.8±18.5, P<0.001, respectively). Intended ablation was the primary determinant of the measured difference (r-square 0.769 & 0.765, respectively). Photorefractive keratectomy corrections over 100µ had significant impact on postoperative spherical equivalent, postoperative defocus equivalent, correction index, difference vector and index of success (P=0.044, P=0.05, P=0.019, P=0.016, P=0.006, respectively), but laser in situ keratomileusis corrections over 100µ had significant impact only on postoperative defocus equivalent, difference vector and index of success (P=0.04, P=0.05). CONCLUSIONS: The results suggest that the wavefront optimize profile seems to over-ablate corneal tissue both in photorefractive keratectomy and laser in situ keratomileusis. Over-ablation exerts significant impact on refractive outcomes only in high spherocylindrical corrections.


Assuntos
Substância Própria/cirurgia , Ceratomileuse Assistida por Excimer Laser In Situ , Lasers de Excimer/uso terapêutico , Miopia/cirurgia , Nomogramas , Ceratectomia Fotorrefrativa , Refração Ocular/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Miopia/fisiopatologia , Estudos Prospectivos , Retalhos Cirúrgicos , Resultado do Tratamento , Acuidade Visual/fisiologia , Adulto Jovem
3.
Graefes Arch Clin Exp Ophthalmol ; 248(5): 731-6, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20072786

RESUMO

BACKGROUND: To evaluate the impact of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK), on retinal nerve fiber layer (RNFL) measurements, by means of scanning laser polarimetry (SLP) GDx VCC (with variable corneal compensation). METHODS: Two groups of 119 myopic patients each were treated by PRK and LASIK respectively; one eye of each patient was randomly selected for the study. RNFL measurements (around the entire calculation circle) was performed in all eyes 1 day before and 1, 3, 6 and 12 months after treatment by using SLP GDx VCC. Corneal compensation was performed in all eyes preoperatively, and in every examination step postoperatively, in order to neutralize the new corneal birefringence. RESULTS: No statistical differences were found between the PRK and LASIK groups, in all preoperative and postoperative RNFL measurements. Only the p values for CCT and mean K-readings preoperatively were statistically significant. CONCLUSIONS: PRK and LASIK do not seem to influence the RNFL measurements at 1st, 3rd, 6th and 12th postoperative months when measured with SLP GDx VCC. The corneal compensation reset is necessary in every step of the examination in order to have reproducible results.


Assuntos
Ceratomileuse Assistida por Excimer Laser In Situ , Miopia/cirurgia , Fibras Nervosas/patologia , Ceratectomia Fotorrefrativa , Células Ganglionares da Retina/patologia , Polarimetria de Varredura a Laser , Adolescente , Adulto , Córnea/cirurgia , Feminino , Humanos , Lasers de Excimer/uso terapêutico , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Estudos Prospectivos , Adulto Jovem
4.
Eur J Ophthalmol ; 20(1): 142-8, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-19882545

RESUMO

PURPOSE: to evaluate the retinal nerve fiber layer(RNFL) profile of healthy controls, persons with exfoliation syndrome (XFS), and patients with exfoliation glaucoma (XFG) and primary open angle glaucoma(POAG). METHODS: One eye from each of 269 participants was analyzed. Fifty eyes were normal , 45 eyes had XFS, 89 eyes had POAG, and 89 had XFG. Glaucoma patients were divided according to the severity of the disease into mild and advanced groups. All participants underwent imaging with the GDx-VCC device. Measurements of the parameters TSNIT average, TSNIT SD, and nerve fiber indicator (NFI) were performed. Polametric RNFL thickness values were compared by means of Bonferroni-corrected t-tests. RESULTS: Regarding control and glaucoma groups, statistically significant differences were identified in all GDx parameters. RNFL thickness values of the control group differed significantly from the values of the XFS group. There was no statistically significant difference between RNFL thickness values for the mild POAG and mild XFG groups or for the advanced POAG and advanced XFG groups. CONCLUSIONS: Polarimetry-determined RNFL in eyes with XFS is thinner than that of healthy eyes. No differences in RNFL thickness were found when eyes with POAG and XFG of similar severity were compared.


Assuntos
Síndrome de Exfoliação/diagnóstico , Glaucoma de Ângulo Aberto/diagnóstico , Fibras Nervosas/patologia , Células Ganglionares da Retina/patologia , Idoso , Gonioscopia , Humanos , Pressão Intraocular , Polarimetria de Varredura a Laser , Tonometria Ocular
5.
Ophthalmol Ther ; 9(3): 677-684, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32566994

RESUMO

INTRODUCTION: Full-thickness macular hole (FTMH) formation is rarely seen in patients with retinitis pigmentosa (RP) and can have an adverse impact on their residual visual function. The underlying mechanisms are unknown, and clinical experience is limited regarding surgical outcomes. Here, we describe the surgical management of FTMH in a young patient with genetically confirmed Usher syndrome, the most common form of syndromic RP. CASE REPORT: A 28-year-old woman presented with blurred vision in her right eye (RE). She had a history of RP and bilateral hearing impairment since childhood. Fundoscopy and spectral-domain optical coherence tomography revealed a FTMH in the RE along with typical RP features bilaterally. After pars plana vitrectomy (PPV) with internal limiting membrane peel and gas tamponade, the FTMH closed. Six months after PPV the patient underwent cataract surgery in the affected eye, and the visual acuity remained stable compared to baseline. The clinical diagnosis of Usher syndrome was genetically confirmed by whole exome sequencing (WES), which revealed the presence of two pathogenic nucleotide variants in trans (compound heterozygosity) in the gene USH2A. CONCLUSION: We report a rare case of successful closure of a FTMH in a patient with Usher syndrome. Surgical treatment of FTMH can help preserve the central vision in RP patients, whose peripheral vision is severely affected.

7.
Ophthalmology ; 114(4): 653-7, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17197028

RESUMO

OBJECTIVE: To evaluate 24-hour intraocular pressure (IOP) efficacy of latanoprost versus travoprost, each given every evening, in exfoliative glaucoma patients. DESIGN: Prospective, observer-masked, crossover comparison. PARTICIPANTS: Forty patients with exfoliation glaucoma. METHODS: Patients with a pressure of >24 mmHg were randomized to latanoprost or travoprost for an 8-week treatment period after a 6-week medicine-free period. Patients were then switched to the opposite treatment for the second period. At untreated baseline and at the end of each treatment period the IOP was measured at 6 am, 10 am, 2 pm, 6 pm, 10 pm, and 2 am. MAIN OUTCOME MEASURE: Diurnal IOP. RESULTS: The mean 24-hour IOP was 25.1+/-2.5 mmHg at baseline, 17.8+/-2.1 mmHg on latanoprost, and 17.3+/-2.2 mmHg on travoprost (P = 0.001). Individual time points were similar between treatments, except at 6 pm when travoprost provided lower IOP (16.7+/-2.6 vs 17.9+/-2.5 mmHg, P<0.001). Adverse events showed more conjunctival hyperemia with travoprost (n = 15) than latanoprost (n = 6; P = 0.03). CONCLUSIONS: Latanoprost and travoprost both significantly reduce the 24-hour IOP from baseline in exfoliative glaucoma, but travoprost may demonstrate a greater hypotensive efficacy in the late afternoon.


Assuntos
Anti-Hipertensivos/uso terapêutico , Cloprostenol/análogos & derivados , Síndrome de Exfoliação/tratamento farmacológico , Glaucoma de Ângulo Aberto/tratamento farmacológico , Pressão Intraocular/efeitos dos fármacos , Prostaglandinas F Sintéticas/uso terapêutico , Idoso , Anti-Hipertensivos/efeitos adversos , Ritmo Circadiano , Cloprostenol/efeitos adversos , Cloprostenol/uso terapêutico , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Latanoprosta , Masculino , Estudos Prospectivos , Prostaglandinas F Sintéticas/efeitos adversos , Travoprost , Resultado do Tratamento , Acuidade Visual , Campos Visuais
8.
Br J Ophthalmol ; 101(6): 719-724, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28045374

RESUMO

PURPOSE: To compare the anatomical and functional outcomes after primary idiopathic epiretinal membrane (ERM) peeling with or without internal limiting membrane (ILM) peeling. DESIGN: A two-centre randomised, controlled clinical trial with 12 months of follow-up. METHODS: One hundred and two eyes of 102 patients were included in the analysis and were randomised into two groups (ILM peeling (P) and non-ILM peeling (NP) group). Inclusion criteria were: Idiopathic ERM confirmed on optical coherence tomography, age ≥18 years, binocular distortion, best-corrected visual acuity (BCVA) ≤90 ETDRS letters, intraocular pressure ≤23 mm Hg and informed consent. The primary outcome measure was the mean change in the ETDRS distance BCVA at 12 months' follow-up for each group. RESULTS: The mean change in distance BCVA at 12 months was 0.30±0.24 logMAR (15 ETDRS letters) in the P group and 0.31±0.23 logMAR (14 ETDRS letters) in the NP group, a change that was not statistically significant (p=0.84). No statistically significant differences were observed when comparing the changes in distance BCVA, the changes in metamorphopsia (Amsler grid) and the changes in central retinal thickness between the two groups at any of the time points studied. CONCLUSIONS: Our analysis suggests that ILM peeling in idiopathic ERM surgery does not result in better visual improvement. The more frequent presence of an uninterrupted interdigitation zone in the P group did not result in a better functional outcome of our patients. No recurrent ERMs were noted in either group.


Assuntos
Membrana Epirretiniana/cirurgia , Retina/patologia , Acuidade Visual , Vitrectomia/métodos , Idoso , Membrana Epirretiniana/diagnóstico , Feminino , Seguimentos , Humanos , Masculino , Retina/cirurgia , Estudos Retrospectivos , Fatores de Tempo , Tomografia de Coerência Óptica , Resultado do Tratamento
9.
Cornea ; 24(6): 688-91, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16015087

RESUMO

PURPOSE: Corneal involvement and disturbances of the tear film have been reported in pseudoexfoliation syndrome (PEX). Tear film deficiencies are correlated with changes in corneal sensitivity. The present study aims at evaluating central corneal mechanical sensitivity (CCMS) in PEX. METHODS: Patients with unilateral or bilateral PEX findings constituted the study group (SG). Age- and gender-matched patients without PEX in either eye constituted the control group (CG). Patients with conditions affecting corneal sensitivity were excluded. CCMS and central corneal thickness (CCT) were measured (using a Cochet-Bonnet esthesiometer and an ultrasonic pachymeter, respectively). Schirmer (ST) and break-up time (BUT) tests were also performed. RESULTS: The SG included 40 patients (24 male, 60%). The CG included 38 patients (25 male, 65.78%). ST scores were significantly lower in the SG compared with the CG (11.45 +/- 2.52 mm and 14.27 +/- 1.18 mm, respectively, P = 0.04). BUT scores were also significantly lower in the SG compared with the CG (7.64 +/- 2.37 mm and 12.43 +/- 3.14 mm, respectively, P = 0.03). CCMS was significantly (P = 0.02) reduced in the SG compared with CG (4.54 +/- 0.23 cm and 5.73 +/- 0.44 cm, respectively). Differences in CCT between the SG and the CG were not statistically significant. CONCLUSIONS: The decrease in CCMS in PEX eyes may be related to decreased BUT and ST scores in PEX, as previously described. However, a direct involvement of sensory nerves may also participate. The reduction in CCMS may have implications for the clinical management of PEX patients.


Assuntos
Córnea/fisiopatologia , Síndrome de Exfoliação/fisiopatologia , Hipestesia/fisiopatologia , Sensação/fisiologia , Lágrimas/fisiologia , Idoso , Idoso de 80 Anos ou mais , Córnea/diagnóstico por imagem , Córnea/inervação , Técnicas de Diagnóstico Oftalmológico , Feminino , Humanos , Aparelho Lacrimal/fisiopatologia , Masculino , Pessoa de Meia-Idade , Nervo Oftálmico/fisiopatologia , Ultrassonografia
10.
Drug Des Devel Ther ; 7: 485-90, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23818759

RESUMO

Age-related macular degeneration (AMD) is the main cause of visual impairment and blindness in people aged over 65 years in developed countries. Vascular endothelial growth factor (VEGF) is a positive regulator of angiogenesis and its proven role in the pathological neovascularization in wet AMD has provided evidence for the use of anti-VEGF agents as potential therapies. In this study, we review the literature for the possible causes of failure after treatment with anti-VEGF agents and attempt to propose an algorithm of suggestive actions to increase the chances of successful management of such difficult cases.


Assuntos
Degeneração Macular/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores , Doenças da Coroide/tratamento farmacológico , Resistência a Medicamentos , Humanos , Degeneração Macular/genética , Falha de Tratamento
11.
Eur J Ophthalmol ; 22(5): 726-33, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22267458

RESUMO

PURPOSE: To perform qualitative evaluation of the aqueous humor (AH) outflow mechanism in glaucoma and nonglaucoma patients by means of tonography assessment and mathematical analysis. METHODS: Sixty-two primary open angle and 58 pseudoexfoliation glaucoma patients were recruited in a non-interventional, observational study between 2004 and 2007. Qualitative and quantitative outflow assessment was acquired by means of a digital tonographer and mathematical analysis. Qualitative results were represented using slope analysis of the change of the AH outflow rate over the tonography study. The results were compared to the control group (CG; n=100) as well as to a pseudoexfoliation group (PEX; n=46). RESULTS: Regarding quantitative analysis, glaucoma groups exhibited significantly lower outflow facility compared to nonglaucoma ones (p<0.001). Outflow facility value was significantly correlated to cup to disc ratio (Pearson correlation r=-0.3, p<0.001). Regarding qualitative analysis, the primary open-angle glaucoma (POAG) group presented a significant profile variation at the beginning of the tonography, expressed as an increased resistance of the AH outflow. Both glaucoma groups exhibited profile stabilization at the end of the measurement, suggesting that the outflow rate remained constant, while nonglaucoma groups followed a continuous reduction of the AH outflow rate throughout the study. CONCLUSIONS: The POAG, PXG, PEX, and CG groups demonstrated both qualitative and quantitative tonographic profile differences. The observed differences in the glaucoma groups suggest a distinct pathomechanism between POAG and PXG. It is suggested that POAG patients have a temporary disruption of the AH flow pathway, while PXG patients have a generalized increased flow resistance.


Assuntos
Humor Aquoso/metabolismo , Glaucoma de Ângulo Aberto/metabolismo , Pressão Intraocular/fisiologia , Tonometria Ocular , Malha Trabecular/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Síndrome de Exfoliação/metabolismo , Humanos , Pessoa de Meia-Idade , Modelos Teóricos
12.
Eur J Ophthalmol ; 21(3): 324-7, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-20872360

RESUMO

PURPOSE: To present a case of ocular decompression retinopathy occurring after an uncomplicated nonpenetrating glaucoma procedure (deep sclerectomy with mitomycin C). METHODS: A 52-year-old man with medically uncontrolled exfoliation glaucoma in the left eye underwent uneventful deep sclerectomy with mitomycin C. The patient had no history or laboratory evidence of any bleeding disorder. RESULTS: On the first postoperative day, visual acuity fell from the preoperative level of Snellen 0.2 to hand movement and the intraocular pressure was 5 mmHg. Funduscopy revealed a small intravitreal hemorrhage and multiple, extended retinal hemorrhages in all quadrants of the fundus. After standard postoperative medication with antibiotic/steroid eyedrops, the patient's visual acuity returned to preoperative levels and the retinal hemorrhages were absorbed. Three and a half months postoperatively, the fundus was free of bleedings. CONCLUSIONS: Although decompression retinopathy has previously been described after penetrating glaucoma surgery, the condition can also occur after uncomplicated deep sclerectomy. Despite the dramatic presentation, the prognosis remains favorable.


Assuntos
Descompressão Cirúrgica/efeitos adversos , Síndrome de Exfoliação/terapia , Glaucoma de Ângulo Aberto/terapia , Mitomicina/administração & dosagem , Hemorragia Retiniana/etiologia , Esclera/cirurgia , Esclerostomia , Alquilantes/administração & dosagem , Terapia Combinada , Síndrome de Exfoliação/tratamento farmacológico , Síndrome de Exfoliação/cirurgia , Angiofluoresceinografia , Glaucoma de Ângulo Aberto/tratamento farmacológico , Glaucoma de Ângulo Aberto/cirurgia , Humanos , Pressão Intraocular , Masculino , Pessoa de Meia-Idade , Hemorragia Retiniana/diagnóstico , Acuidade Visual/fisiologia , Hemorragia Vítrea/etiologia
13.
J Med Case Rep ; 5: 152, 2011 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-21496288

RESUMO

INTRODUCTION: Corneal collagen cross-linking is a rather new technique that uses riboflavin and ultraviolet A light for collagen fiber stabilization in keratoconus corneas. Other than reversible side effects, the preliminary results of corneal collagen cross-linking studies suggest that it is a rather safe technique. In this report, we demonstrate a case of corneal melting after corneal collagen cross-linking for keratoconus corneas associated with an acute inflammatory response. CASE PRESENTATION: A 23-year-old Caucasian man with keratoconus cornea stage 1 to 2 underwent uneventful corneal collagen cross-linking treatment according to the Dresden protocol. The next day the patient had intense photophobia, watering and redness of the eye, and his visual acuity was limited to counting fingers. Slit lamp biomicroscopy revealed severe corneal haze accompanied by non-specific endothelial precipitates following an acute inflammatory response. Mild inflammation could be detected in the anterior chamber. Moreover, the re-epithelialization process could barely be detected. His corneal state gradually deteriorated, resulting in descemetocele and finally perforation. CONCLUSION: In this report, we present a case of a patient with corneal melting after standard corneal collagen cross-linking treatment for keratoconus corneas following an acute inflammatory response. Despite modifying postoperative treatment, elaboration of all apparent associated causes by the treating physicians and undergoing extensive laboratory testing, the patient developed descemetocele, which led to perforation. Our report suggests that further research is necessary regarding the safety of corneal collagen cross-linking in keratoconus corneas.

14.
J Cataract Refract Surg ; 37(12): 2160-6, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21996515

RESUMO

PURPOSE: To assess flap-thickness predictability with a pendular microkeratome (130 µm head). SETTING: Eye Institute of Thrace, Democritus University of Thrace, Alexandroupolis, Greece. DESIGN: Clinical trials. METHODS: The study comprised 263 eyes (132 patients). Laser in situ keratomileusis was performed using the 130 µm head of the Carriazo pendular microkeratome; right eyes were treated first. Ultrasound pachymetry and topography were used for central corneal thickness (CCT) and keratometry (K) measurements. Evaluation included flap thickness, flap diameter, and flap shape. RESULTS: The mean flap thickness was 125 µm ± 22 (SD) (range 74 to 187 µm) in right eyes and 112 ± 21 µm (range 61 to 190 µm) in left eyes. Flap thickness was significantly correlated with preoperative CCT (r = 0.271; P<.001) but not with K values or the manifest refraction spherical equivalent (P>.15). Right eyes had thicker flaps than left eyes (P<.001); both were significantly below the 130 µm head thickness (mean flap thickness 119.2 ± 22.8 µm; P<.001). The mean achieved flap diameter was 9.2 mm using the 9.0 ring and 9.8 mm using the 10.0 mm ring. Flap-thickness stabilization and convergence between right eyes and left eyes occurred after 100 consecutive flap cuts. CONCLUSIONS: Flap-thickness predictability was influenced by preoperative CCT only. All cuts were significantly thinner than the head thickness regardless of the suction ring size. Second surgical eyes had thinner flaps, possibly from blade deterioration from the first cut. Approximately 100 flaps were required as a learning curve.


Assuntos
Substância Própria/anatomia & histologia , Hiperopia/cirurgia , Ceratomileuse Assistida por Excimer Laser In Situ/instrumentação , Lasers de Excimer/uso terapêutico , Miopia/cirurgia , Retalhos Cirúrgicos , Adolescente , Adulto , Substância Própria/diagnóstico por imagem , Topografia da Córnea , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Refração Ocular/fisiologia , Reprodutibilidade dos Testes , Ultrassonografia , Acuidade Visual/fisiologia , Adulto Jovem
15.
Clin Ophthalmol ; 4: 937-45, 2010 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-20856586

RESUMO

PURPOSE: To develop, characterize, and validate a prototype digital aqueous humor outflow tonographer (DAHOM). MATERIAL AND METHODS: The DAHOM was developed, characterized, and validated in three phases. Phase 1 involved construction of the sensor. This was broadly based on the fundamental design of a typical Schiotz tonographer with a series of improvements, including corneal indentation, which was converted to an electrical signal via a linear variable differential transducer, an analog signal which was converted to digital via ADC circuitry, and digital data acquisition and processing which was made possible by a serial port interface. Phase 2 comprised development of software for automated assessment of the outflow facility. Automated outflow facility assessment incorporated a series of fundamental improvements in comparison with traditional techniques, including software-based filtering of ripple noise and extreme variations, rigidity impact analysis, and evaluation of the impact of patient age, central corneal thickness, and ocular axial length. Phase 3 comprised characterization and validation of DAHOM, for which we developed an experimental setup using porcine cadaver eyes. DAHOM's repeatability was evaluated by means of Cronbach's alpha and intraclass correlation coefficient. The level of agreement with a standard Schiotz tonographer was evaluated by means of paired t-tests and Bland-Altman analysis in human eyes. RESULTS: The experimental setup provided the necessary data for the characterization of DAHOM. A fourth order polynomial equation provided excellent fit (R square >0.999). DAHOM demonstrated high repeatability (Cronbach's alpha ≥0.997; intraclass correlation coefficient ≥0.987) and an adequate level of agreement with a standard Schiotz tonographer. CONCLUSIONS: This study presents the development, characterization, and validation of a prototype digital tonographer. DAHOM demonstrates high repeatability and a sufficient level of agreement with a typical Schiotz tonographer, while its digital design remedies known vulnerabilities of conventional tonographers.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA