The document discusses automated perimetry, which quantifies sensitivity across the visual field. It describes key terminology like isopters, scotomas, and luminance. Different testing strategies are outlined, including threshold perimetry using SITA. Printout zones are explained, such as raw data, reliability indices, and global indices like mean deviation. Common defects are described. Visual field progression is monitored using GPA event and trend analysis.
PPT on BASIC CONCEPTION ON HUMPHERY AUTOMATED PERIMETRY Nalin Nayan
The document discusses Humphrey automated perimetry, including basic concepts of visual field testing and perimetry. It covers the anatomy of the visual pathway, types of visual field defects, and different testing programs available on Humphrey perimeter such as Central 30-2, Central 24-2, and peripheral or specialty tests. Threshold tests directly measure light sensitivity at specific points while screening tests provide an initial evaluation of the visual field.
Ultrasound biomicroscopy (UBM) provides high-resolution imaging of ocular structures in the anterior segment of the eye using 50 MHz ultrasound. UBM allows visualization of tissues like the ciliary body and zonules that are not visible by slit lamp examination. UBM can be used to qualitatively and quantitatively evaluate the anterior segment structures and has applications in diagnosing and monitoring conditions like glaucoma, corneal diseases, tumors, and intraocular lenses. While UBM provides excellent detail, it has limitations including only being able to image about 5mm into the eye and requiring contact with the eye, unlike anterior segment OCT which is non-contact.
UBM and ASOCT provide high-resolution cross-sectional images of the anterior segment including the cornea, anterior chamber, angle, and iris. ASOCT uses optical coherence tomography with a wavelength of 1310nm for improved penetration and reduced retinal damage compared to posterior segment OCT. It allows high-speed imaging of dynamic structures. ASOCT has applications in assessing corneal diseases and procedures, glaucoma (including angle anatomy and iridotomy evaluation), and intraocular lens implantation. Measurements of angle width parameters help evaluate angle closure risk. While valuable for objective angle assessment, ASOCT cannot image all anatomical structures involved in glaucoma.
This document discusses various imaging techniques used to evaluate glaucoma, including OCT, HRT, and GDx. OCT uses interferometry to measure retinal nerve fiber layer thickness. HRT uses confocal laser scanning to create 3D images of the optic nerve and measure disc parameters. GDx uses scanning laser polarimetry to measure retinal nerve fiber layer thickness and detect glaucomatous damage through thickness maps, deviation maps, and TSNIT plots compared to normative data. Together these quantitative imaging techniques provide objective assessment to aid in glaucoma diagnosis and detection of progression.
This document discusses using optical coherence tomography (OCT) to analyze the macula, retinal nerve fiber layer (RNFL), and optic nerve head in patients with glaucoma or suspected glaucoma. It describes how OCT can measure macular thickness, RNFL thickness, and optic disc parameters. Five case studies are presented showing how structural changes seen on OCT correlate with functional defects on visual field tests or clinical findings. The document concludes by mentioning Doppler OCT may help understand the role of blood flow in glaucoma and other optic neuropathies.
This document discusses transpupillary thermotherapy (TTT), a technique that uses low-level heat delivered through the pupil to treat conditions like choroidal neovascularization (CNV), choroidal melanoma, and retinoblastoma. TTT works by inducing tumor necrosis or occlusion of neovascular vessels via localized hyperthermia above 42°C. The document outlines the laser parameters used to treat CNV via TTT, noting that a pilot study found 19% of patients experienced improved vision, 56% had no change, and 25% had declining vision, while 94% saw reduced exudation. TTT is currently being used and studied as a treatment for several ocular diseases.
Iol power calculation in pediatric patientsAnisha Rathod
- Many factors affect intraocular lens (IOL) power calculation in pediatric patients including age at surgery, laterality, amblyopia, axial length, keratometry, and expected myopic shift due to ongoing eye growth.
- Normal eye development involves rapid growth of the axial length and changes in lens power in the first years of life.
- Target postoperative refraction must account for this myopic shift and generally involves undercorrecting more in younger patients.
- Accurate biometry using immersion ultrasound or optical techniques is important to minimize errors from corneal compression.
- Formulas, IOL type and position can further influence outcomes.
How to interpret the visual field printout
Learn basic terms of visual field analysis
How to diagnose glaucomatous field defect
How to diagnose neurological field defect
PPT on BASIC CONCEPTION ON HUMPHERY AUTOMATED PERIMETRY Nalin Nayan
The document discusses Humphrey automated perimetry, including basic concepts of visual field testing and perimetry. It covers the anatomy of the visual pathway, types of visual field defects, and different testing programs available on Humphrey perimeter such as Central 30-2, Central 24-2, and peripheral or specialty tests. Threshold tests directly measure light sensitivity at specific points while screening tests provide an initial evaluation of the visual field.
Ultrasound biomicroscopy (UBM) provides high-resolution imaging of ocular structures in the anterior segment of the eye using 50 MHz ultrasound. UBM allows visualization of tissues like the ciliary body and zonules that are not visible by slit lamp examination. UBM can be used to qualitatively and quantitatively evaluate the anterior segment structures and has applications in diagnosing and monitoring conditions like glaucoma, corneal diseases, tumors, and intraocular lenses. While UBM provides excellent detail, it has limitations including only being able to image about 5mm into the eye and requiring contact with the eye, unlike anterior segment OCT which is non-contact.
UBM and ASOCT provide high-resolution cross-sectional images of the anterior segment including the cornea, anterior chamber, angle, and iris. ASOCT uses optical coherence tomography with a wavelength of 1310nm for improved penetration and reduced retinal damage compared to posterior segment OCT. It allows high-speed imaging of dynamic structures. ASOCT has applications in assessing corneal diseases and procedures, glaucoma (including angle anatomy and iridotomy evaluation), and intraocular lens implantation. Measurements of angle width parameters help evaluate angle closure risk. While valuable for objective angle assessment, ASOCT cannot image all anatomical structures involved in glaucoma.
This document discusses various imaging techniques used to evaluate glaucoma, including OCT, HRT, and GDx. OCT uses interferometry to measure retinal nerve fiber layer thickness. HRT uses confocal laser scanning to create 3D images of the optic nerve and measure disc parameters. GDx uses scanning laser polarimetry to measure retinal nerve fiber layer thickness and detect glaucomatous damage through thickness maps, deviation maps, and TSNIT plots compared to normative data. Together these quantitative imaging techniques provide objective assessment to aid in glaucoma diagnosis and detection of progression.
This document discusses using optical coherence tomography (OCT) to analyze the macula, retinal nerve fiber layer (RNFL), and optic nerve head in patients with glaucoma or suspected glaucoma. It describes how OCT can measure macular thickness, RNFL thickness, and optic disc parameters. Five case studies are presented showing how structural changes seen on OCT correlate with functional defects on visual field tests or clinical findings. The document concludes by mentioning Doppler OCT may help understand the role of blood flow in glaucoma and other optic neuropathies.
This document discusses transpupillary thermotherapy (TTT), a technique that uses low-level heat delivered through the pupil to treat conditions like choroidal neovascularization (CNV), choroidal melanoma, and retinoblastoma. TTT works by inducing tumor necrosis or occlusion of neovascular vessels via localized hyperthermia above 42°C. The document outlines the laser parameters used to treat CNV via TTT, noting that a pilot study found 19% of patients experienced improved vision, 56% had no change, and 25% had declining vision, while 94% saw reduced exudation. TTT is currently being used and studied as a treatment for several ocular diseases.
Iol power calculation in pediatric patientsAnisha Rathod
- Many factors affect intraocular lens (IOL) power calculation in pediatric patients including age at surgery, laterality, amblyopia, axial length, keratometry, and expected myopic shift due to ongoing eye growth.
- Normal eye development involves rapid growth of the axial length and changes in lens power in the first years of life.
- Target postoperative refraction must account for this myopic shift and generally involves undercorrecting more in younger patients.
- Accurate biometry using immersion ultrasound or optical techniques is important to minimize errors from corneal compression.
- Formulas, IOL type and position can further influence outcomes.
How to interpret the visual field printout
Learn basic terms of visual field analysis
How to diagnose glaucomatous field defect
How to diagnose neurological field defect
Optical coherence tomography (OCT) is useful for imaging both the anterior and posterior segments in glaucoma. Posterior segment OCT allows quantification of retinal nerve fiber layer thickness, optic nerve head parameters, and ganglion cell layer thickness. Changes in these measurements over time can help detect glaucomatous progression. Anterior segment OCT visualizes angle anatomy and structures after glaucoma surgery. OCT provides objective data but results must be interpreted carefully while considering limitations such as variability between devices and lack of representation in normative databases.
This document provides guidance on how to draw fundus diagrams. It lists the requisites needed which include an examination table, indirect ophthalmoscope, 20D lens, scleral depressor, and colored pencils. It then provides detailed instructions on how to represent various retinal structures, abnormalities, tumors, detachments and other findings using different colors and markings. Remember that choroidal tumors are drawn in brown, retinoblastomas are outlined in blue and colored yellow, and retinoschisis involves outlining the inner layer in blue and cross hatching or coloring the open portions.
This document discusses various methods for assessing the anterior chamber angle, including subjective tests like the oblique flashlight test and Van Herrick's technique, as well as objective tests like gonioscopy, ultrasound biomicroscopy (UBM), and anterior segment optical coherence tomography (AS-OCT). Gonioscopy is considered the reference standard but can be subjective, while UBM and AS-OCT provide high resolution cross-sectional images of the angle but have limitations like requiring specialized equipment. No single test is perfect, and gonioscopy remains essential for glaucoma evaluation and management despite advances in imaging technology.
1) Biometry is the process of measuring the eye to determine the ideal intraocular lens power for cataract surgery. It involves measuring the corneal power and axial length of the eye.
2) Traditional A-scan ultrasound biometry measures axial length using sound waves, but has limitations like variable corneal compression. Newer devices like the IOL Master use optical interferometry and are non-contact.
3) Proper technique and accounting for factors like intraocular lens material are important for accurate biometry and intraocular lens power calculation. Inaccuracies can result in postoperative refractive surprises.
1. Optical coherence tomography (OCT) uses light interferometry to perform high-resolution, cross-sectional imaging of the retina. It provides quantitative measurements of retinal nerve fiber layer thickness.
2. OCT images are analyzed to detect structural changes in the optic nerve head and retinal nerve fiber layer that can indicate glaucoma, often before visual field defects appear. Parameters like retinal nerve fiber layer thickness, cup-to-disc ratio, and nerve fiber layer deviation maps are used to diagnose and monitor glaucoma progression.
3. Macular ganglion cell complex thickness, which includes the retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer, can also detect early glaucomatous loss
Optical coherence tomography in glaucoma - Dr Shylesh DabkeShylesh Dabke
This document discusses optical coherence tomography (OCT) in evaluating glaucoma. It begins by outlining the importance of early glaucoma detection to prevent vision loss. OCT is described as the most appropriate technology for detecting glaucoma as it can assess retinal nerve fiber layer (RNFL) thickness before visual field or optic disc changes occur. RNFL thinning is an early sign of glaucoma. The document then provides details on OCT technology and analysis of RNFL thickness, optic nerve head, and macula to diagnose and monitor glaucoma. RNFL analysis, especially of the inferior quadrant, is highlighted as the most useful OCT assessment for detecting early glaucoma.
OCT-Angiography is a non-invasive imaging method that uses light to visualize the retinal and choroidal vasculature in 3D without dye injection. It works by detecting the movement of red blood cells on sequential OCT scans to identify blood vessels. The document describes the technical aspects and clinical applications of several commercial OCT-Angiography systems.
Corneal pachymetry is the measurement of corneal thickness, which is an important indicator of corneal health. Various techniques for measuring corneal thickness are described, including ultrasonic pachymetry (considered the gold standard), ultrasound biomicroscopy, manual and specular optical pachymetry, anterior segment optical coherence tomography, Pentacam, and Pachycam. Factors like ethnicity and refraction can affect normal corneal thickness measurements. Measurements outside the normal range of 500-575 microns may indicate conditions like corneal thinning, edema, or abnormal intraocular pressure.
A 32-year-old male presented with complaints of double vision for one year. Orthoptic evaluation revealed esophoria and high divergence insufficiency. The patient had difficulty fusing images with the binocular imbalance testing. He was initially diagnosed with divergence insufficiency and prescribed prism glasses for first-line management. After using the prism glasses and undergoing vision therapy, his symptoms improved and his diagnosis was changed to esophoria. He was advised to continue vision therapy for further improvement.
This document provides a history of the development of the ophthalmoscope and techniques for indirect ophthalmoscopy. It discusses key developments such as Mery making the first ophthalmoscopic observations in 1704, Cumming and Brucke explaining the principles in 1846, and Helmholtz describing the basic principles in 1852. Later sections cover the design of monocular and binocular indirect ophthalmoscopes, use of scleral depressors, techniques for peripheral examination, and diagnostic uses of indentation. The document presents information on indirect ophthalmoscopy in a detailed but structured manner.
Meibomian gland dysfunction (MGD) is a chronic abnormality of the meibomian glands that results in an altered tear film and ocular surface disease. The meibomian glands secrete an oily substance called meibum that prevents tear film evaporation. MGD can be obstructive or non-obstructive and is commonly caused by ductal blockage that impairs meibum secretion. Symptoms include eye irritation, redness, burning and watering. Treatment involves warm compresses, lid scrubs, and topical agents like antibiotics, anti-inflammatories, and tear supplements.
Keratometry measures the curvature of the cornea using the reflection of light off the corneal surface. There are two main types - manual keratometers using movable mires or prisms to assess curvature, and automated keratometers using photosensors. Keratometry is used to detect astigmatism, monitor corneal conditions, and assist in contact lens and refractive surgery. It provides important information but has limitations as it only measures the central cornea and assumes a symmetrical shape.
The document discusses visual field testing in glaucoma. It defines the visual field and perimetry, and describes the major types of clinical perimetry tests including full threshold, SITA standard, and SITA fast on Humphrey and normal, dynamic, and TOP strategies on Octopus. It explains parameters such as test patterns, reliability, age-corrected plots, tests like GHT and Bebie curve, and global indices including MD, PSD, SF, and CPSD. The purpose of visual field testing in glaucoma is to detect and monitor disease by measuring light sensitivity across the retinal field.
This document discusses surgical induced astigmatism following cataract surgery. It notes that astigmatism has a significant impact on vision and is influenced by surgical technique and incision size and type. Various factors can induce astigmatism including incision location and size, suture type and placement, and wound compression or gape. Evaluating astigmatism involves tools like retinoscopy, keratometry and corneal topography. Managing astigmatism may involve selective suture removal to reduce cylindrical error over time.
This document provides information on retinal lasers, including their mechanism of action, properties that distinguish them from normal light, types of tissue interaction, parameters that can be adjusted, delivery methods, and applications in treating various retinal conditions. It describes techniques like photocoagulation, photodynamic therapy, and transpupillary thermotherapy; the lasers and parameters used; and indications for treating diseases such as diabetic retinopathy, retinal vein occlusions, and wet age-related macular degeneration.
This lecture is based on post-graduate students of Ophthalmology (DO, DCO, MCPS, FCPS, MS) and optical principle of GAT has to know for a student to use the instrument friendly
A visual field test examines a person's peripheral vision. It determines the extent of a person's side vision and how well they can see objects outside of central vision. During a test, a person focuses on a central point while a test stimulus is moved into their visual field from different angles and the person reports when they detect it. Common visual field tests include confrontation testing, where an examiner uses their hand as the stimulus, and automated perimetry which uses a computer. Visual field defects can indicate diseases of the eye, optic nerve or brain and present in characteristic patterns depending on the underlying condition. Proper administration of visual field tests and avoiding artifacts is important for obtaining accurate results.
This document provides information about corneal topography and keratometry. It defines the cornea and its dimensions. It describes the historical evolution of keratometry from its first description in 1619 to modern computerized corneal topography systems. The document explains the principles, procedures, techniques, and applications of keratometry and corneal topography in evaluating the cornea. It also discusses the limitations and assumptions of keratometry measurements.
The document discusses two imaging techniques used to detect glaucoma - HRT (Heidelberg Retinal Tomography) and GDx (scanning laser polarimetry). HRT uses confocal scanning laser ophthalmoscopy to generate a 3D topographic image of the optic disc and retinal nerve fiber layer. GDx measures the retinal nerve fiber layer thickness around the optic disc using scanning laser polarimetry, which analyzes the polarization of light passing through the birefringent retinal nerve fiber layer. Both provide objective measures of the optic disc and retinal nerve fiber layer but have limitations such as dependency on accurate contour line placement for HRT.
This document provides an overview of visual field examination and interpretation of automated perimetry results. It discusses the different types of perimetry testing including kinetic, static, and automated threshold testing. Important testing parameters like reliability indices, total deviation plots, and glaucoma hemifield tests are explained. Common visual field defects seen in conditions like glaucoma are demonstrated. The summary emphasizes that visual field defects must be reproducible to confirm abnormalities and clinical correlation is important when interpreting results.
This document defines perimetry and discusses the objectives, normal visual field parameters, common terms, and types of perimetry. It also describes automated static perimetry testing protocols, algorithms, stimulus intensity, and interpretations of visual field printouts including reliability indices, total deviation plots, and glaucoma hemifield tests. Factors that can cause errors in perimetry testing are also outlined.
Optical coherence tomography (OCT) is useful for imaging both the anterior and posterior segments in glaucoma. Posterior segment OCT allows quantification of retinal nerve fiber layer thickness, optic nerve head parameters, and ganglion cell layer thickness. Changes in these measurements over time can help detect glaucomatous progression. Anterior segment OCT visualizes angle anatomy and structures after glaucoma surgery. OCT provides objective data but results must be interpreted carefully while considering limitations such as variability between devices and lack of representation in normative databases.
This document provides guidance on how to draw fundus diagrams. It lists the requisites needed which include an examination table, indirect ophthalmoscope, 20D lens, scleral depressor, and colored pencils. It then provides detailed instructions on how to represent various retinal structures, abnormalities, tumors, detachments and other findings using different colors and markings. Remember that choroidal tumors are drawn in brown, retinoblastomas are outlined in blue and colored yellow, and retinoschisis involves outlining the inner layer in blue and cross hatching or coloring the open portions.
This document discusses various methods for assessing the anterior chamber angle, including subjective tests like the oblique flashlight test and Van Herrick's technique, as well as objective tests like gonioscopy, ultrasound biomicroscopy (UBM), and anterior segment optical coherence tomography (AS-OCT). Gonioscopy is considered the reference standard but can be subjective, while UBM and AS-OCT provide high resolution cross-sectional images of the angle but have limitations like requiring specialized equipment. No single test is perfect, and gonioscopy remains essential for glaucoma evaluation and management despite advances in imaging technology.
1) Biometry is the process of measuring the eye to determine the ideal intraocular lens power for cataract surgery. It involves measuring the corneal power and axial length of the eye.
2) Traditional A-scan ultrasound biometry measures axial length using sound waves, but has limitations like variable corneal compression. Newer devices like the IOL Master use optical interferometry and are non-contact.
3) Proper technique and accounting for factors like intraocular lens material are important for accurate biometry and intraocular lens power calculation. Inaccuracies can result in postoperative refractive surprises.
1. Optical coherence tomography (OCT) uses light interferometry to perform high-resolution, cross-sectional imaging of the retina. It provides quantitative measurements of retinal nerve fiber layer thickness.
2. OCT images are analyzed to detect structural changes in the optic nerve head and retinal nerve fiber layer that can indicate glaucoma, often before visual field defects appear. Parameters like retinal nerve fiber layer thickness, cup-to-disc ratio, and nerve fiber layer deviation maps are used to diagnose and monitor glaucoma progression.
3. Macular ganglion cell complex thickness, which includes the retinal nerve fiber layer, ganglion cell layer, and inner plexiform layer, can also detect early glaucomatous loss
Optical coherence tomography in glaucoma - Dr Shylesh DabkeShylesh Dabke
This document discusses optical coherence tomography (OCT) in evaluating glaucoma. It begins by outlining the importance of early glaucoma detection to prevent vision loss. OCT is described as the most appropriate technology for detecting glaucoma as it can assess retinal nerve fiber layer (RNFL) thickness before visual field or optic disc changes occur. RNFL thinning is an early sign of glaucoma. The document then provides details on OCT technology and analysis of RNFL thickness, optic nerve head, and macula to diagnose and monitor glaucoma. RNFL analysis, especially of the inferior quadrant, is highlighted as the most useful OCT assessment for detecting early glaucoma.
OCT-Angiography is a non-invasive imaging method that uses light to visualize the retinal and choroidal vasculature in 3D without dye injection. It works by detecting the movement of red blood cells on sequential OCT scans to identify blood vessels. The document describes the technical aspects and clinical applications of several commercial OCT-Angiography systems.
Corneal pachymetry is the measurement of corneal thickness, which is an important indicator of corneal health. Various techniques for measuring corneal thickness are described, including ultrasonic pachymetry (considered the gold standard), ultrasound biomicroscopy, manual and specular optical pachymetry, anterior segment optical coherence tomography, Pentacam, and Pachycam. Factors like ethnicity and refraction can affect normal corneal thickness measurements. Measurements outside the normal range of 500-575 microns may indicate conditions like corneal thinning, edema, or abnormal intraocular pressure.
A 32-year-old male presented with complaints of double vision for one year. Orthoptic evaluation revealed esophoria and high divergence insufficiency. The patient had difficulty fusing images with the binocular imbalance testing. He was initially diagnosed with divergence insufficiency and prescribed prism glasses for first-line management. After using the prism glasses and undergoing vision therapy, his symptoms improved and his diagnosis was changed to esophoria. He was advised to continue vision therapy for further improvement.
This document provides a history of the development of the ophthalmoscope and techniques for indirect ophthalmoscopy. It discusses key developments such as Mery making the first ophthalmoscopic observations in 1704, Cumming and Brucke explaining the principles in 1846, and Helmholtz describing the basic principles in 1852. Later sections cover the design of monocular and binocular indirect ophthalmoscopes, use of scleral depressors, techniques for peripheral examination, and diagnostic uses of indentation. The document presents information on indirect ophthalmoscopy in a detailed but structured manner.
Meibomian gland dysfunction (MGD) is a chronic abnormality of the meibomian glands that results in an altered tear film and ocular surface disease. The meibomian glands secrete an oily substance called meibum that prevents tear film evaporation. MGD can be obstructive or non-obstructive and is commonly caused by ductal blockage that impairs meibum secretion. Symptoms include eye irritation, redness, burning and watering. Treatment involves warm compresses, lid scrubs, and topical agents like antibiotics, anti-inflammatories, and tear supplements.
Keratometry measures the curvature of the cornea using the reflection of light off the corneal surface. There are two main types - manual keratometers using movable mires or prisms to assess curvature, and automated keratometers using photosensors. Keratometry is used to detect astigmatism, monitor corneal conditions, and assist in contact lens and refractive surgery. It provides important information but has limitations as it only measures the central cornea and assumes a symmetrical shape.
The document discusses visual field testing in glaucoma. It defines the visual field and perimetry, and describes the major types of clinical perimetry tests including full threshold, SITA standard, and SITA fast on Humphrey and normal, dynamic, and TOP strategies on Octopus. It explains parameters such as test patterns, reliability, age-corrected plots, tests like GHT and Bebie curve, and global indices including MD, PSD, SF, and CPSD. The purpose of visual field testing in glaucoma is to detect and monitor disease by measuring light sensitivity across the retinal field.
This document discusses surgical induced astigmatism following cataract surgery. It notes that astigmatism has a significant impact on vision and is influenced by surgical technique and incision size and type. Various factors can induce astigmatism including incision location and size, suture type and placement, and wound compression or gape. Evaluating astigmatism involves tools like retinoscopy, keratometry and corneal topography. Managing astigmatism may involve selective suture removal to reduce cylindrical error over time.
This document provides information on retinal lasers, including their mechanism of action, properties that distinguish them from normal light, types of tissue interaction, parameters that can be adjusted, delivery methods, and applications in treating various retinal conditions. It describes techniques like photocoagulation, photodynamic therapy, and transpupillary thermotherapy; the lasers and parameters used; and indications for treating diseases such as diabetic retinopathy, retinal vein occlusions, and wet age-related macular degeneration.
This lecture is based on post-graduate students of Ophthalmology (DO, DCO, MCPS, FCPS, MS) and optical principle of GAT has to know for a student to use the instrument friendly
A visual field test examines a person's peripheral vision. It determines the extent of a person's side vision and how well they can see objects outside of central vision. During a test, a person focuses on a central point while a test stimulus is moved into their visual field from different angles and the person reports when they detect it. Common visual field tests include confrontation testing, where an examiner uses their hand as the stimulus, and automated perimetry which uses a computer. Visual field defects can indicate diseases of the eye, optic nerve or brain and present in characteristic patterns depending on the underlying condition. Proper administration of visual field tests and avoiding artifacts is important for obtaining accurate results.
This document provides information about corneal topography and keratometry. It defines the cornea and its dimensions. It describes the historical evolution of keratometry from its first description in 1619 to modern computerized corneal topography systems. The document explains the principles, procedures, techniques, and applications of keratometry and corneal topography in evaluating the cornea. It also discusses the limitations and assumptions of keratometry measurements.
The document discusses two imaging techniques used to detect glaucoma - HRT (Heidelberg Retinal Tomography) and GDx (scanning laser polarimetry). HRT uses confocal scanning laser ophthalmoscopy to generate a 3D topographic image of the optic disc and retinal nerve fiber layer. GDx measures the retinal nerve fiber layer thickness around the optic disc using scanning laser polarimetry, which analyzes the polarization of light passing through the birefringent retinal nerve fiber layer. Both provide objective measures of the optic disc and retinal nerve fiber layer but have limitations such as dependency on accurate contour line placement for HRT.
This document provides an overview of visual field examination and interpretation of automated perimetry results. It discusses the different types of perimetry testing including kinetic, static, and automated threshold testing. Important testing parameters like reliability indices, total deviation plots, and glaucoma hemifield tests are explained. Common visual field defects seen in conditions like glaucoma are demonstrated. The summary emphasizes that visual field defects must be reproducible to confirm abnormalities and clinical correlation is important when interpreting results.
This document defines perimetry and discusses the objectives, normal visual field parameters, common terms, and types of perimetry. It also describes automated static perimetry testing protocols, algorithms, stimulus intensity, and interpretations of visual field printouts including reliability indices, total deviation plots, and glaucoma hemifield tests. Factors that can cause errors in perimetry testing are also outlined.
This document discusses the visual field and visual field testing. It defines the visual field as the part of the environment that can be detected by a steady eye. It then discusses the physiological basis of the visual field and factors that can affect visual field testing results, such as stimulus characteristics and patient factors. The document also summarizes different types of visual field defects and explains common perimetry techniques and their advantages. It provides details on visual field test interpretation, including reliability indices, total and pattern deviation plots, and classification of results.
This document discusses visual field testing and perimetry. It defines the visual field and describes common visual field defects. It then covers the indications, methods, and terminology of visual field testing. Specific details are provided on threshold testing strategies, reliability indices, and how to interpret visual field printout maps and global indices. Criteria for diagnosing glaucomatous visual field loss and detecting progression over time are also outlined.
- Visual field examination tests the peripheral sensitivity of the retina and visual pathways. It is important for assessing topographic sensitivity and detecting visual field defects.
- Automated perimetry provides standardized, quantitative tests to measure threshold sensitivity across the visual field. It allows for reliable long-term monitoring to detect glaucomatous progression.
- Interpretation of visual field tests involves analyzing parameters like total deviation plots, pattern deviation plots, and global indices to identify patterns indicative of glaucoma according to established criteria. Clinical correlation with optic nerve examination is also important.
This document discusses visual field examination and interpretation of automated perimetry in glaucoma. It provides details on the physiology of the visual field and different types of visual field defects. It also describes various methods of visual field examination including kinetic and static perimetry as well as clinical techniques. Automated perimetry devices like Humphrey Field Analyzer and their advantages are discussed. Important aspects of visual field test interpretation including reliability indices, total and pattern deviation plots, and global indices are summarized.
The document discusses the field of vision, including its anatomy and testing methods. It notes that the field of vision is like an island surrounded by blindness, with the fovea being the summit of highest sensitivity and the blind spot being the trough of zero sensitivity. It describes kinetic and static perimetry testing methods and different types of visual field defects seen in conditions like glaucoma and neurological disorders. Global indices, reliability indices, and corrected pattern deviation maps are used to analyze perimetry results. Factors affecting testing and new techniques like FDT perimetry are also mentioned.
This document discusses visual field testing and perimetry. It defines visual field as the area that can be seen around a central point of fixation. Perimetry involves systematically measuring light sensitivity across the visual field using techniques like kinetic and static perimetry. Common perimetry devices include Humphrey, Octopus, and Goldmann perimeter. The document outlines stimulus parameters, test strategies, interpretation of results, and alternative perimetry techniques targeting different retinal pathways.
The document defines the visual field and describes methods for examining it, including confrontation testing, tangent screen testing, Amsler grid testing, static and kinetic perimetry, and Humphrey Field Analyzer (HFA) testing. It discusses the normal limits of the visual field and reliability indices used to evaluate HFA test results, such as fixation losses, false positives, and false negatives. Single field analysis results from the HFA including sensitivity values, gray scale maps, and total and pattern deviation plots are also summarized.
This document summarizes a seminar on assessing the visual field using automated perimetry. It defines key terminology used in visual field testing like threshold, apostilbs, decibels, and indices. It describes the components and functioning of the Humphrey Field Analyzer automated perimeter. It provides criteria for diagnosing glaucoma based on visual field tests and categorizes the severity of visual field defects as early, moderate, or severe. It also outlines how to recognize progressive damage by comparing tests over time.
Low vision patient have serious visual problems that have caused serious visual loss.
1. Contrast sensitivity testing and visual field testing
2. subjective testing of patients with media loss
# potential acuity meter
# interferometry
# photostress recovery test
# glare test
# color vision test
# dark adaptometry
3. objective testing of retinal loss
# USG
ERG/EOG
The document summarizes various techniques for visual field testing, including kinetic perimetry, static perimetry, and newer automated techniques. Kinetic perimetry involves moving a stimulus towards fixation until it is perceived, while static perimetry presents stationary targets at varying luminances to find thresholds. Automated perimetry allows standardization, estimates reliability, and provides computerized analysis. Factors like refractive error, media clarity, and fatigue can influence results, which are analyzed using reliability indices, deviation plots, and global indices. Advances include techniques sensitive to short wavelengths, flicker, motion, and multifocal VEPs.
The document discusses how to interpret visual field tests, specifically the Humphrey Visual Field test. It provides details on:
- The anatomy and physiology of the visual field and hill of vision.
- Types of perimetry tests including static, kinetic, threshold, and supra-threshold tests.
- Components and procedures of Humphrey Visual Field testing including stimuli, test patterns like 24-2 and 10-2, and testing types.
- What the test printout shows including reliability indices, threshold values, deviation maps, and gaze tracking records.
- What abnormalities are looked for in glaucoma, neurological diseases, and retinal diseases and how the test helps in diagnosis and monitoring of these conditions.
There are several new developments in perimetry that test different subsets of retinal ganglion cells. Short wavelength perimetry assesses blue-yellow color opponent pathways mediated by K cells. Frequency doubling perimetry and motion perimetry primarily test M cells. High pass resolution perimetry and acuity perimetry mainly assess P cells. These targeted perimetry techniques may detect glaucomatous damage earlier than standard perimetry and provide a more detailed assessment of visual function.
This document discusses automated perimetry, which is used to evaluate the visual field. It begins by explaining the importance of perimetry in diagnosing and monitoring glaucoma and other conditions. It then defines key concepts like the visual field and hill of vision. The document discusses the components and procedures of automated perimetry testing, including factors that influence the results like stimulus characteristics, fixation monitoring, and testing strategies. It describes different perimetry tests and their applications in evaluating various eye diseases. In summary, the document provides an overview of automated perimetry, its role in eye care, and the technical aspects of performing this important visual field assessment test.
This document discusses static automated perimetry, which determines the threshold of the retina at fixed points to assess the visual field. It describes the retinal area that can be perceived, variables that affect perimetry tests, different test patterns used, classification of Humphrey field tests, strategies for presenting stimuli, analyzing results, and classifying visual field defects seen in glaucoma. Key points are that static perimetry determines the differential light sensitivity across the retina and compares results to age-normalized databases to detect losses.
To know Humphrey visual field analyser
To know about various types of perimetry
To identify field defect
To recognize that field defect is due to glaucoma or neurological lesion
To know that field defect is progressive or not
Interpretation of HVFA
This document summarizes key aspects of perimetry testing. It defines the normal visual field and describes how perimetry can be used to detect functional vision loss and monitor disease progression. Two main types of perimetry are discussed: kinetic and static. Details are provided on testing strategies, stimuli brightness, interpreting results like total deviation and reliability indices. The document emphasizes the importance of perimetry in glaucoma and neurological diagnosis and management.
Here is the updated list of Top Best Ayurvedic medicine for Gas and Indigestion and those are Gas-O-Go Syp for Dyspepsia | Lavizyme Syrup for Acidity | Yumzyme Hepatoprotective Capsules etc
TEST BANK For Community Health Nursing A Canadian Perspective, 5th Edition by...Donc Test
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share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Knee anatomy and clinical tests 2024.pdfvimalpl1234
This includes all relevant anatomy and clinical tests compiled from standard textbooks, Campbell,netter etc..It is comprehensive and best suited for orthopaedicians and orthopaedic residents.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Basavarajeeyam - Ayurvedic heritage book of Andhra pradesh
Automated perimetry
1. Moderators: Prof. H. Ashraf
Dr. S M Zakir
Presenter Armaan Ahmed
INTERPRETATION OF AUTOMATED
PERIMETRY
2. Automated Perimetry
●Automated threshold static perimetry
quantifies the sensitivity of a patient’s
central vision using efficient and
standardized testing algorithms.
●Perimetry is essential in glaucoma
management and also frequently
useful in diagnosis and management
of some neurological and retinal
diseases.
3. ● Visual field is a 3-D
structure akin to a
Hill-of-Vision
● Normal field is
horizontally oval with a
shallow inferonasal
depression
50 ˚ superiorly
60 ˚ nasally
70 ˚ inferiorly , and
90 ˚ temporally
5. ❖Scotoma
● It is an area of reduced(‘relative’) or
total(‘absolute’)loss of vision that is
surrounded by a field of normal or a relatively
well-preserved vision.
❖Blind spot
● Physiological scotoma corresponding to optic
nerve head
● b/w 10-20 ˚ .It is located temporally and slightly
inferiorly.
6. LUMINANCE
• Intensity/brightness of a light stimulus
• measured in apostilb or decibel (logarithmic
unit)
• The humphrey perimeter presents white light
stimuli that can be varied in brightness with
maximum brightness of 0dB (10000asb) and
minimum brightness of 51dB(0.08asb).
• In standardized testing,the dimmest stimulus
that can be seen by a young well trained
observer is little less than 40dB.
7. Visible threshold
● Luminance of a given stimulus at which it
is perceived 50 % of the time when
presented statically.
8. PERIMETRY VS CAMPIMETRY
❖Perimetry – measurement of visual field
by projecting targets onto a curved
surface
❖Campimetry – measurement of visual
field by projecting targets onto a flat
surface
10. Why Automation?
● Removes subjectivity of perimetrist
● Improves uniformity and reproducibility
● Computer provides facility of random
presentation of targets, estimation of
patient reliability and statistical
evaluation of data
● Faster ,more accurate and informative
11.
12. Zone 1- patients data and test data
Test Data
Fixation monitor: Blind spot
Fixation Target: Central
Colour of the stimulus: White
Back ground illumination: 31.5asb
Stimulus size: Goldmann Size III
Threshold test pattern:
Testing strategy:
Patient Data
Name of the patient:
Date of birth and age:
Pupil Diameter:
Visual Acuity:
Refractive error correction for N.V.
13. DOB OF THE PATIENT- Since the interpretation of raw data by
STATPAC is age dependent, it is very important to enter the age
of the patient accurately. Otherwise the patients raw data will be
compared to mean normal threshold value of a wrong age group
and thus derived decibel deviations from the normal will form
the numerical plot .
SIZE OF THE STIMULUS – The Humphrey Perimeter is capable
of testing with five standard Goldman stimulus sizes.
Size III stimulus is used almost exclusively.
Size V stimulus is sometimes employed in advanced field loss.
Sizes I,II and IV are almost never used in static visual field
testing.
14. EFFECT OF SIZE OF PUPIL-
. Normal size 3-4 mm.
. Constricted pupil is thought to give rise to diffuse visual
field defects and edge scotomas
. Pupil size less than 2mm is more likely to exert a
significant effect on the overall level of the visual field.
17. • REFRACTIVE ERROR-
• Refractive blur reduces visual sensitivity to
perimetric stimuli.
• One dioptre of refractive blur in undilated patient will
produce a little more than 1dB of depression of field
of vision when testing with Goldmann Size III
stimulus.
• Hence near vision must be properly corrected ,
otherwise the visual field will show a generalized
depression .
18. Strategies
● Suprathreshold – Suprathreshold perimetry
involves testing with stimuli of luminance
above the expected normal threshold levels for
an age-matched population to assess whether
these are detected; in other words, testing to
check that a subject can see stimuli that would
be seen by a normal person of the same age.
It enables testing to be carried out rapidly to
indicate whether function is grossly normal or
not.
● However, it is not highly quantitative, and so is
usually reserved for screening.
19. Threshold perimetry
● It is used for detailed assessment of the hill of
vision by plotting the threshold luminance value in
various locations in the visual field and comparing
the results with age-matched ‘normal’ values.
● Here the threshold is crossed in one direction
with large increments, then crossed again to ‘fine-
tune’ the result with smaller increments.
● Threshold testing is quantitatively detailed and is
therefore used for monitoring glaucomatous
fields.
20.
21. SITA (Swedish Interactive Threshold
Algorithm):
● A newer, faster thresholding algorithm
● Shows more abnormal points in PDP than
the full-threshold programme.
● Provides shorter testing time with good
accuracy & reproducibility by less number of
stimuli.
Types :
a) SITA standard – Average testing time
50% of FTT
b) SITA fast - 30% less time than SITA std
but less accurate.
22. TESTING PATTERNS
● Most important defects in glaucoma occur within the central
30° radius of field, so this is the area most commonly tested.
● The 30-2 test pattern measures visual sensitivity at 76
locations within 30° of fixation.
● The 24-2 test pattern consists of 54 most central test
locations of the 30-2 pattern .
23. ● The number after the dash (–2 or sometimes –1) describes the
pattern of the points tested.
● The –2 strategy involves a grid of test points spaced 6° apart,
offset from the vertical and horizontal meridia whereas the
-1 includes points along the vertical and horizontal meridia.
24. Other examples include-
1) 10–2 which is used to assess an area of central radius 10° –
as defects here may threaten central vision as in macular
diseases and
2) FF (‘full field’) – 120 (120°) is used to assess neurological
defects
25. ZONE 2- FOVEAL THRESHOLD AND
RELIABILITY INDICES
●Foveal threshold –it is useful to measure
the foveal threshold at the very beginning
of the test . If the patient is not properly
focused on the bowl ,foveal sensitivity will
be reduced along with the remainder of
the field.
●Visual Acuity-BCVA should be 6/36 or
better for the visual field to be tested.
26. Reliability indices-
•Fixation losses-The fixation
loss rate measures patients gaze
stability.During the test 5% of
the stimulus will be presented on
the blind spot. The patients
response to this stimulus
presentation will tell that the
patient is not gazing straight or
is looking from side to side
during test.
•fixation losses more than 20%
are considered to be of fixation
unreliable.
27. •False positive response-
• These are detected when
stimulus is accompanied by a
sound.If the sound alone is
presented and the patient still
responds,a false positive is
recorded.
- FP >15% is strongly
associated with compromised
test.
-With a high FP
score,grey scale appears
abnormally pale.
28.
29.
30. ● False negative
response-
● These are detected by
presenting a stimulus
much (9dB)brighter
than threshold at a
location where the
threshold has already
been determined. If the
patient fails to respond
a false negative is
recorded
- In general >30% of
FN is considered
abnormal
31. ZONE-3 RAW DATA
● The raw data is the exact retinal sensitivity in
dB units of the selected points calculated by
field analyser.
● In raw data 0 dB = absolute scotoma.
● 40 dB is the highest retinal sensitivity.
● In same patient the raw data calculated by
different strategies is not exactly similar .
33. ZONE-5
TOTAL DEVIATION NUMERICAL PLOT
• The measured retinal
sensitivity is now
compared with the
mean normal sensitivity
of those points of same
age groups of the
patient and calculates
the difference between
them at each point and
plots them as TDNP.
34. • If there is no field loss – TDNP must have
deviation value 0 to -2
Localized field loss- high deviation values at
those particular areas.
Uniform generalized field loss-all the deviation
values will be almost symmetrical and the
difference between max and min deviation
values will be minimal.
In irregular generalized field defects – the
deviation values in TDNP will show dissimilar
deviation values and the difference between
max and min values will be very high .
35. Conversion of numerical data to
probability data
● P<5% indicates the retinal
sensitivity of that point is seen
in < 5% of normal population.
● P<2%, P<1%,P<0.5%
● Probability statements are
based on the distribution seen
in the normal population .
● Darker the symbol,the greater
the probability of abnormality
as indicated by P value.
● Higher the P value lesser the
chances of field being
abnormal
36. ZONE-6
TOTAL DEVIATION PROBABILITY
PLOT
• STATPAC calculates the
P value of each dB
deviation in the TDNP.
• A symbol is given to each
P value as shown in the
fig.
• Each deviation in TDNP is
converted to a symbolic
form according to its P
value and plotted as
TDPP.
• By seeing TDPP we
cannot tell the depth of
defect at that point .
37. ZONE-7
PATTERN DEVIATION NUMERICAL
PLOT
PDNP is derived from the
total deviation values
adjusted for any
generalized decrease in
sensitivity in the overall
field which might be
caused by other factors
such as lens opacities or
miosis. It therefore
demonstrates localized
defects such as occur in
glaucoma.
38. ZONE 8
PATTERN DEVIATION PROBABILITY
PLOT
● PDPP is the symbolic
representation of P value of
each numerical threshold
deviation values of PDNP or
the symbolic representation
of p value of each measured
retinal sensitivity corrected
for generalized loss.
● In uniform generalized
depression we do not see
any scotoma in PDPP.
● In irregular generalized
depression, the mild and
moderate field defects are
eliminated and the deep
defects are highlighted in the
PDPP.
39. ZONE-9 GLOBAL INDICES
• The basic global field
indices are-
1.Mean deviation(MD)
2.Short term fluctuation (SF)
3.Pattern standard
deviation(PSD)
4.Corrected pattern standard
deviation(CPSD)
40. MEAN DEVIATION
• MD gives an indication of the overall sensitivity of the
field.
• The positive value indicates better overall retinal
sensitivity than normal observer.
• Negative value indicates that the patient’s overall
sensitivity is worse than the average normal individual.
41. PATTERN STANDARD
DEVIATION
• It is a measure of focal loss or variability within the field
taking into account any generalized depression in the hill of
vision.
● An increased PSD is therefore a more specific indicator of
glaucomatous damage than MD.
42. SHORT TERM
FLUCTUATION
• It is an index of intra test variation.
• At 10 preselected points the retinal sensitivity
will be calculated twice.
• The result of 1st series of the threshold values
at these points are compared with the 2nd
series of threshold values at these points and
the difference between them is calculated .
• It is not available for SITA strategy.
• A high SF means either decreased reliability
or an early finding indicative of glaucoma .
43. CORRECTED PATTERN
STANDARD DEVIATION(CPSD)
● It is the PSD corrected for short term
fluctuations.
● It indicate the variability between
adjacent points that may be due to
disease rather than due to intra-test
variability .
44. ZONE-10 GLAUCOMA HEMIFIELD
TEST
• GHT evaluates 5
zones in the upper
field and compares
these zones to
their mirror image
zones in the lower
field .
• The zones are
constructed in the
approx patterns of
retinal nerve fibres.
45. ● Depending upon the values between upper and
lower clusters of points the following five
messages may be displayed ;
● Outside normal limit –It is displayed whenever at
least one zone pair differs by an amount found in
fewer than 1% of normal subjects.
● Border line – It is displayed whenever at least one
zone pair differs by an amount found in fewer than
3% but more than 1% of normal subjects.
● General reduction in sensitivity /Abnormally high
sensitivity : These messages are presented
whenever even the best test point locations are
either so low or so high as to be at levels seen in
fewer than 0.5% of normal subjects.
● Within normal limit .- if none of the above conditions
47. VISUAL FIELD SEVERITY GRADING SYSTEM
as proposed by Hodapp, Anderson, and Parrish.
Stage 1: Early Defect :
Mean deviation (MD)
≤ –6.00 dB and at least
one of the following:
A) On pattern deviation plot,
<25% of the points depressed
below the 5% level and less
than 15% depressed below 1%
level.
B) No point within central 5 ˚ with
sensitivity <15dB.
48. Stage 2: Moderate
Defect :
MD of –6.01 to –12.00 dB and at
least one of the following:
A) On pattern deviation plot,
greater than or equal to 25% but
fewer than 50% of points
depressed below the 5% level,
and greater than or equal to 15%
but fewer than 25% of points
depressed below 1% level
B) At least 1 point within central 5°
with sensitivity of < 15 dB but no
point within central 5° with
sensitivity of < 0 dB
C) Only 1 hemifield containing a
point with sensitivity < 15 dB
within 5° of fixation
49. Stage 3: Advanced
Defect : MD of –12.01 dB to
–20.00 dB and at least one of
the following:
A) On pattern deviation plot,
greater than or equal to 50%
but fewer than 75% of points
depressed below the 5% level
and greater than or equal to
25% but fewer than 50% of
points depressed below 1%
level
B) Any point within central 5°
with sensitivity of < 0 dB
C) Both hemifields containing a
point(s) with sensitivity < 15 dB
within 5° of fixation
50. Stage 4: Severe Defect :
MD of –20.00 dB and at least
one of the following:
A) On pattern deviation plot,
greater than or equal to 75%
of points depressed below
the 5% level and greater than
or equal to 50% of points
depressed below 1% level
B )At least 50% of points
within central 5° with
sensitivity of < 0 dB
C )Both hemifields containing
greater than 50% of points
with sensitivity < 15 dB
within 5° of fixation
51. Stage 5: End-Stage Disease -
Unable to perform Humphrey visual fields in
“worst eye” due to central scotoma
or “worst eye” visual acuity of 6/60 or
worse due to primary open-angle
glaucoma. “Best eye” may be any stage
58. GLAUCOMA PROGRESSION
ANALYSIS
● Helps to identify and quantify visual field progression.
● Includes:
- Event Analysis &
- Trend Analysis
● Event analysis assess whether there has been any
statistically significant worsening in the visual field .
● Trend analysis’s goal is to quantify any observed rate
of change.
59. GPA SUMMARY REPORT
● Preferred report for use in glaucoma
management.Includes-
1)Two baseline fields
2)An event analysis of the most recent test.
3)A trend analysis of all available tests.
60. GPA Event Analysis
● GPA provides a plain language event analysis
called GPA Alert which displays either of the
following 2 messages:
Possible Progression Likely Progression
•When three or more
test points show
statistically significant
deterioration on two
consecutive follow up
examinations.
•When the same three or
more significantly
deteriorated test points
appear in atleast three
consecutive follow-up
tests.
61. ● GPA change probability maps use triangle
symbols to highlight statistically significant
deterioration from a baseline consisting of the
average of two chosen tests.Each follow up is
compared to baseline and :
● OPEN TRIANGLES:indicate test point locations
with deterioration that is statistically significant
at the 5% level.
● HALF BLACK TRIANGLES:indicate test point
locations that have shown statistically
significant deterioration in two consecutive
follow-up examinations.
● FILLED IN BLACK TRIANGLES :Designate
locations where such deterioration has been
observed in three or more consecutive tests.
62. GPA TREND ANALYSIS
● The goal of trend analysis is to quantify how
quickly each patient is changing and thereby
identify patients who are progressing at rates that
threaten to cause considerable visual disability
within the patient’s expected lifetime.
● Here we estimate the rate of progression using
linear regression analysis of the Visual Field
Index(VFI) over time.
63. VISUAL FIELD INDEX (VFI)
● It is the enhancement of Mean Deviation(MD) that
is designed to be less affected by cataract and is
more sensitive to changes near the centre of field
so as to better co-relate with ganglion cell loss.
● VFI is thus a single number that summarizes each
patients visual field status as a % of normal age
corrected sensitivity.
● VFI of 100% implies completely normal visual
field and
● VFI of 0% implies a perimetrically blind visual
field.
67. SELECTIVE PERIMETRY
There are thought to be three subtypes of retinal ganglion cells that
connect the retina to the lateral geniculate nucleus (LGN):
1)The most numerous of these three subtypes, the midget ganglion
cells, connect to the parvocellular layer of the LGN.
2)The parasol cells, which comprise about 10% of the ganglion cell
population, project to the magnocellular layers of the LGN.
3) The blue-yellow ganglion cells, or B-Y cells, project to the koniocellular
layers of the LGN.
68. SHORT WAVELENGTH AUTOMATED
PERIMETRY(SWAP)
● Also known as “Blue on yellow perimetry”.
● It selectively tests the B-Y ganglion cells that project to the
koniocellular layers of the LGN.
● Sensitivity to blue light (mediated by blue cone photoreceptors)
is adversely affected relatively early in glaucoma.
● SWAP is mostly being used currently to test patients who have
suspicious optic discs but normal SAP fields
● LIMITATIONS-
1) Lengthy test
2) Longer learning curve
3) Influence of nuclear sclerosis
4) Higher test variability.
5) No clinical utility in moderate-advanced glaucoma
69. FREQUENCY DOUBLING
CONTRAST TEST(FDT)
● FDT relies on what is known as the frequency doubling
illusion.
● It selectively tests cells in the magnocellular
pathway(thought to be damaged first in glaucoma),
perhaps allowing earlier glaucoma diagnosis than
white-on-white perimetry.