Publications by authors named "Uday K Addepalli"
Purpose: To study the effects of age, sex, intraocular pressure (IOP), corneal thickness, axial length (AXL), disc area, and the signal strength of the scan on optical coherence tomography (OCT) parameters of normal subjects in the L V Prasad Eye Institute-Glaucoma Epidemiological and Molecular Genetic Study (LVPEI-GLEAMS), a population-based study.
Design: Cross-sectional study.
Methods: A total of 1,100 eyes (1,100 subjects) of normal adults aged between 40 and 80 years from LVPEI-GLEAMS underwent macular and optic nerve head imaging with spectral-domain OCT (SDOCT).
Objectives: To assess the ability of teleophthalmoscopic grading of peripheral anterior chamber depth (PACD) using the van Herick (vH) technique in detecting gonioscopically occludable angle; and to determine whether combining results from vH grading and ocular biometry can improve the accuracy to diagnose gonioscopically occludable angle METHODS: This cross-sectional study was an offshoot of a rural population-based study, Glaucoma Epidemiology and Molecular Genetic Study (GLEAMS). A masked urban ophthalmologist graded digital slit lamp photographs of PACD by vH technique. Sussman four-mirror lens was used to perform dark room indentation gonioscopy.
View Article and Find Full Text PDFPurpose: To report the prevalence of primary glaucoma as identified by study optometrists of the L. V. Prasad Eye Institute - Glaucoma Epidemiology and Molecular Genetics Study (LVPEI-GLEAMS).
View Article and Find Full Text PDFBackground: Heidelberg retina tomogram (HRT) and optical coherence tomography (OCT) are two widely used imaging modalities to evaluate the optic nerve head (ONH) in glaucoma.
Purpose: To compare the ONH parameters of HRT3 and high-definition OCT (HD-OCT) and evaluate their diagnostic abilities in perimetric and preperimetric glaucoma.
Design: Cross-sectional analysis.
Background: There is paucity of data on the inter-observer agreement and diagnostic accuracy between a primary-care technician (vision technician) and an ophthalmologist. Hence, the current study was conducted to assess the accuracy of vision technicians, to screen potentially sight-threatening ocular conditions at rural vision centres of southern India and their agreement with an ophthalmologist.
Methods: In July to August 2010, patients presenting to seven vision centres in Adilabad district (Andhra Pradesh) were selected and screened in a masked manner by seven vision technicians followed by an examination by a consultant ophthalmologist.
Purpose: To compare the abilities of retinal nerve fiber layer (RNFL) parameters of variable corneal compensation (VCC) and enhanced corneal compensation (ECC) algorithms of scanning laser polarimetry (GDx) in detecting various severities of glaucoma.
Methods: Two hundred and eighty-five eyes of 194 subjects from the Longitudinal Glaucoma Evaluation Study who underwent GDx VCC and ECC imaging were evaluated. Abilities of RNFL parameters of GDx VCC and ECC to diagnose glaucoma were compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities, and likelihood ratios.
Purpose: To evaluate the ability of normative database classification (color-coded maps) of spectral domain optical coherence tomograph (SDOCT) in detecting wedge shaped retinal nerve fiber layer (RNFL) defects identified on photographs and the factors affecting the ability of SDOCT in detecting these RNFL defects.
Methods: In a cross-sectional study, 238 eyes (476 RNFL quadrants) of 172 normal subjects and 85 eyes (103 RNFL quadrants with wedge shaped RNFL defects) of 66 glaucoma patients underwent RNFL imaging with SDOCT. Logistic regression models were used to evaluate the factors associated with false positive and false negative RNFL classifications of the color-coded maps of SDOCT.
Purpose: To compare the abilities of peripapillary retinal nerve fiber layer (RNFL) parameters of spectral domain optical coherence tomograph (SDOCT) and scanning laser polarimeter (GDx enhanced corneal compensation; ECC) in detecting preperimetric glaucoma.
Methods: In a cross-sectional study, 35 preperimetric glaucoma eyes (32 subjects) and 94 control eyes (74 subjects) underwent digital optic disc photography and RNFL imaging with SDOCT and GDx ECC. Ability of RNFL parameters of SDOCT and GDx ECC to discriminate preperimetric glaucoma eyes from control eyes was compared using area under receiver operating characteristic curves (AUC), sensitivities at fixed specificities and likelihood ratios (LR).
Purpose: To evaluate the effect of typical scan score (TSS), when within the acceptable limits, on the diagnostic performance of retinal nerve fibre layer (RNFL) parameters with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in glaucoma.
Methods: In a cross-sectional study, 203 eyes of 160 glaucoma patients and 140 eyes of 104 control subjects underwent RNFL imaging with the ECC protocol of SLP. TSS was used to quantify atypical birefringence pattern (ABP) images.
Importance: Standard automated perimetry is the current criterion standard for assessment of visual field (VF) loss in glaucoma. The 3 commonly used reliability indices to judge the quality of standard automated perimetry results are fixation losses (FLs) and false-positive (FP) and false-negative (FN) response rates. However, the influence of reliability indices, when within the manufacturer-recommended limits, on VF classification has been sparsely studied.
View Article and Find Full Text PDFPurpose: To compare the abilities of standard automated perimetry (SAP) and spectral-domain optical coherence tomography (SDOCT) in diagnosing eyes with glaucomatous optic neuropathy (GON).
Methods: In a cross-sectional study, 280 eyes of 175 subjects referred to tertiary eye care center by general ophthalmologists for a glaucoma evaluation underwent retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) imaging with SDOCT. All subjects had at least 2 reliable and repeatable SAP.
Purpose: To evaluate the ability of the neuroretinal rim (NRR) rules determined using spectral domain optical coherence tomography (SDOCT) in diagnosing glaucoma and to study the effect of optic disc size and disease severity on the diagnostic ability of these rules.
Methods: In a cross-sectional study, 125 eyes of 96 glaucoma patients and 96 eyes of 72 control subjects underwent optic nerve head (ONH) imaging with SDOCT. Inferior (I), superior (S), nasal (N) and temporal (T) NRR areas were automatically determined by the sdoct software.
Purpose: We determined the diagnostic performance of ganglion cell-inner plexiform layer (GCIPL) parameters of high definition optical coherence tomography (HD-OCT) in perimetric and preperimetric glaucoma, and compared it to optic nerve head (ONH) and peripapillary retinal nerve fiber layer (RNFL) parameters.
Methods: In a cross-sectional study, 53 eyes of normal subjects and 83 eyes of glaucoma patients (62 perimetric and 21 preperimetric) from the Longitudinal Glaucoma Evaluation Study (LOGES) underwent HD-OCT imaging with Optic Disc and Macular Cube protocols. Diagnostic abilities of GCIPL, ONH, and RNFL parameters were determined using area under receiver operating characteristic curves (AUC) and likelihood ratios (LR).
Purpose: To evaluate the relationship between the reference standard used to diagnose glaucoma and the diagnostic ability of spectral domain optical coherence tomograph (SDOCT).
Methods: In a cross-sectional study, 280 eyes of 175 consecutive subjects, referred to a tertiary eye care center for glaucoma evaluation, underwent optic disc photography, visual field (VF) examination, and SDOCT examination. The cohort was divided into glaucoma and control groups based on 3 reference standards for glaucoma diagnosis: first based on the optic disc classification (179 glaucoma and 101 control eyes), second on VF classification (glaucoma hemifield test outside normal limits and pattern SD with P-value of <5%, 130 glaucoma and 150 control eyes), and third on the presence of both glaucomatous optic disc and glaucomatous VF (125 glaucoma and 155 control eyes).
Purpose: To report the outcomes of trabeculectomy in eyes with glaucoma in microspherophakia.
Materials And Methods: In a retrospective non-comparative case series, we analyzed 29 eyes of 18 patients with glaucoma in microspherophakia, who underwent primary trabeculectomy between 1998 and 2012. Success was defined as complete if the intraocular pressure (IOP) was ≤ 21 and > 5 mm Hg without any antiglaucoma medication and qualified if IOP ≤ 21 and >5 mm Hg with or without antiglaucoma medications.
Background: With the advent of spectral domain optical coherence tomography (SDOCT), there has been a renewed interest in macular region for detection of glaucoma. However, most macular SDOCT parameters currently are thickness parameters which evaluate thinning of the macular layers but do not quantify the extent of area over which the thinning has occurred. We therefore calculated a new macular parameter, "ganglion cell complex surface abnormality ratio (GCC SAR)" that represented the surface area over which the macular thickness was decreased.
View Article and Find Full Text PDFPurpose: To evaluate the effect of scan quality on the diagnostic accuracies of optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) parameters of spectral-domain optical coherence tomography (SD OCT) in glaucoma.
Design: Cross-sectional study.
Methods: Two hundred fifty-two eyes of 183 control subjects (mean deviation [MD]: -1.
Purpose: To evaluate the ability of the optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) parameters of spectral domain optical coherence tomograph (SDOCT) in detecting preperimetric glaucoma.
Methods: In a cross-sectional study, 34 preperimetric glaucoma eyes (34 patients) and 72 control eyes (72 subjects) with large physiologic optic disc cupping underwent ONH, RNFL, and GCC imaging with SDOCT. Preperimetric glaucoma was diagnosed in the presence of glaucomatous optic neuropathy on masked evaluation of optic disc photographs by two glaucoma experts and normal visual fields.
Aim: To evaluate optic nerve head, retinal nerve fibre layer (RNFL) and ganglion cell complex (GCC) thickness measurements in children operated for primary congenital glaucoma (PCG) using spectral domain optical coherence tomography (SDOCT).
Methods: In a case-control study, 45 eyes of 37 children operated for PCG and 72 eyes of 41 normal children underwent optic nerve head, RNFL and GCC imaging with SDOCT. Differences in SDOCT parameters between PCG and control group, correlation between SDOCT parameters and a range of clinical variables, namely preop corneal diameter, intraocular pressure, degree of corneal oedema and age at which surgery was performed in PCG eyes, were evaluated.
Purpose: In the developing world, more than 90% of glaucoma is undetected due to the lack of appropriate screening methods. The LV Prasad Eye Institute Glaucoma Epidemiology and Molecular Genetic Study (LVPEI-GLEAMS) is a population-based study which aims to estimate the prevalence of, along with clinical, systemic and genetic risk factors for glaucoma in a rural population sampled from the state of Andhra Pradesh, India. The study aims to develop community screening strategies to diagnose glaucoma.
View Article and Find Full Text PDFPurpose: To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects.
Methods: In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements.
Purpose: To compare the central and peripheral pachymetry measurements determined using Orbscan IIz (Bausch & Lomb, Rochester, NY), Visante optical coherence tomography (OCT; Carl Zeiss Meditec, Dublin, CA), and RTVue OCT (Oculus Technologies, Wynwood, WA) with ultrasound pachymetry in eyes with established keratoconus and to evaluate the agreement between them.
Design: Evaluation of diagnostic technologies.
Participants: One hundred six eyes of 67 consecutive patients with a clinical diagnosis of keratoconus ranging in age from 12 to 40 years.
Purpose: To report the clinical features, management, and treatment outcomes of glaucoma in microspherophakia.
Methods: Medical records of 159 eyes of 80 subjects with microspherophakia were reviewed. The clinical features at presentation, presence of glaucoma, methods of treatment, and their outcomes were noted.
Purpose: To evaluate the relationship between intraocular pressure (IOP) and the rate of visual field (VF) progression in treated glaucoma.
Methods: In a clinic-based, retrospective study, data of consecutive primary open-angle and angle-closure glaucoma patients with ≥ 5 VFs between 1989 and 2008 were analyzed. The Guided Progression Analysis software, which provides the rate of change of Visual Field Index per year, was used to assess the rate of progression (ROP).
Purpose: To evaluate the influence of a control group on the diagnostic accuracy of spectral-domain optical coherence tomography (SD-OCT) in early glaucoma.
Methods: In a diagnostic, case-control study, 119 eyes of 60 normal subjects with no findings suspicious for glaucoma (control cohort 1); 76 eyes of 41 subjects referred by general ophthalmologists as glaucoma suspects based on optic disc morphology, but found by glaucoma experts to be normal but with physiological variations in their optic nerves (control cohort 2); and 65 eyes of 46 early-glaucoma patients (cases) underwent imaging of the optic nerve head (ONH), retinal nerve fiber layer (RNFL), and ganglion cell complex (GCC) by SD-OCT.
Results: Areas under the receiver operating characteristic curves (AUC) of ONH parameters discriminating glaucomatous eyes from normal eyes of control cohort 2 were significantly lesser (P < 0.