Computerized Campimetry in Daily Practice

By Claudio Norberto, Francisco Sales and Norberta Silva

This book became possible after much encouragement from colleagues and friends. For a long time, I wanted to write something similar for the main reason that some colleagues had difficulty understanding the details of the field. Some of them even minimizing its value, considering its usefulness superficial.

There is nothing very complicated in campimetry. Fortunately, it is a very visual matter, as are lesions of the neural fibers of the retina and the optic nerve head. Something similar to disciplines such as Anatomy, Histology, and Histopathology, among others.

The main purpose of this book is to intend to make interest in campimetry possible, encouraging the recall of what has been learned and forgotten, or the learning to use an underutilized resource, which can facilitate not only the daily work of each one but also allows improve the vision of patients, carriers of pathologies that can be resolved or mitigated, adding, at least, hope.

• Language: English
• Publisher: BadPress
• Release date: May 5, 2021
• ISBN: 9781071599501

Book preview

CLAUDIO NORBERTO ALVES DA SILVA (in memoriam)

Ophthalmologist

Retired Full Professor at UFRPE

Postgraduate from the Paulista School of Medicine (UNIFESP)

Fellow at the Ophthalmological Clinic at Hospital de S. Amaro - Recife,

Sergio Guilherme Alves Clinic - Recife

Specialization in Ophthalmology - CB - Faculty of Medicine, UFPE

FRANCISCO SALES DE MELO SILVA

Ophthalmologist

Resident at Clínica Pacini - Brasília

Fellow of the University of Perugia - Italy,

Pacini Clinic, Brazilian Center for Eye Surgery -

Goiânia - GO and Hospital de Olhos de Pernambuco - HOPE

Dedicatory

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To my wife Maria Isabel, my children Francisco (co-author of this book), Claudia, Norberta, my grandchildren Natália, Diego, Vanessa, Isabela (Alexander) and Guilherme, my brothers, brothers-in-law and family members who always encouraged me in everything. Especially to my parents (in Memoriam), to Prof. Dr. Sylvio Paes Barreto (in Memoriam) and my brother Dr. Sergio Guilherme Alves (in Memoriam).

Claudio Norberto

Claudio Norberto

To my parents, my ex-wife Marize, my children Isabela (Alexander) and Guilherme, and Prof. Dr. Leopoldo Pacini Neto.

Francisco Sales

ACKNOWLEDGMENT

We are immensely grateful to God our Father, the Creator, to the Holy Spirit to our Lord Jesus Christ our Savior. We are also grateful for the assistance and cooperation of these people who served us, encouraged, and helped in the preparation of this book: 

Eng. Adriano Ayrton de Azevedo Melo - PCLab

Eng. Célio Armando Costa Leite - PCLab

Norberta de Melo Silva - Reviewer

Susana de Moraes - Diagrammer

PREFACE

Prof. Dr. Jayme Figueiredo (in memoriam)

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With great joy, I confess myself honored by the appointment of Drs. Claudio Norberto Alves da Silva and Francisco Sales de Melo Silva so that I would preface the book COMPUTERIZED CAMPIMETRY IN DAILY PRACTICE, of which they are authors.

First, I want to congratulate you on the appropriateness of the chosen theme, as it is a relevant subject in the current world, especially for the enormous sum of knowledge that already exists in it. It also deserves to be emphasized the didactic way of the presentation, thus allowing great profits can result.

The examination of the Visual Field is constituted in ophthalmological semiotics, a remarkable resource in the evaluation of facts related to the areas of the retina, the optic nerve and the optical pathways. Consequently, widely used in conditions such as glaucoma, whose neuropathy that characterizes it has forms of presentation that are peculiar to it. This allows not only to characterize, but to detect progression, as well as stability despite the treatment instituted.

A real interest in topics related to retinopathies, retinal degeneration, and dystrophies, etc. could not be dispensed with. Furthermore, the Authors did with great propriety, emphasize not only the modifications of the visual field as well as the stability despite the instituted treatment, as well as photographic documentation, retinography, fluorescent angiography, with the interpretation of the images obtained. Very enlightening.

Finally, I want to congratulate the authors of the book and emphasize my greater contentment in verifying the seriousness of their professional experience, people I have known for a long time, and who, due to the publication in question reveal their interest in deepening not only their knowledge, as well as the medical community for whom their work is proposed.

INDEX

Page

PRESENTATION

This book became possible after much encouragement from colleagues and friends. For a long time, I wanted to write something similar for the main reason that some colleagues had difficulty understanding the details of the field. Some of them even minimizing its value, considering its usefulness superficial.

Nothing is complicated in campimetry. Fortunately, it is a very visual matter, as are lesions of the neural fibers of the retina and the optic nerve head. Something similar occurs to disciplines such as Anatomy, Histology and Histopathology, among others.

The main purpose of this book is to intend to make interest in campimetry possible, encouraging the recall of what has been learned and forgotten, or the learning to use an underutilized resource, which can facilitate not only the daily work of each one, but also allow improve the vision of patients, carriers of pathologies that can be resolved or alleviated, adding, or at least, hope.

Each chapter of this book presents the text and then exercises on the subject treated, with the purpose of reviewing or fixing each concept, at the same time that the reader assesses his learning and progresses in learning.

Each exercise is related to the previous subject, maintaining proximity to that one. The responses maintain this same relationship.

Not all people maintain the same level of attention on what they read or do, presenting quick intervals in which attention is suppressed, and then returning to the initial stage in a short period. This cycle is repeated regularly, depending on the interest in what is done or read. Exercises make it easier to maintain the level of attention by concentrating it and, consequently, increasing the level of what is learned or remembered.

The reader should not follow the sequence of the story as it is presented if he does not want to. He should try to be as free as possible to choose what he wants to read, to review or to learn.

As for the exercises, it is good to do them if you are willing and feel comfortable with this and even check the answer in advance, filing as we call it in the Northeast or pasting as they say in the South. Each exercise was programmed to remember or learn more smoothly and even fun.

Campimetry is only difficult when there is no disposition to understand it. Spending a little time can be beneficial and, consequently, benefit patients, our obligation.

Ophthalmologists, like any doctor, are interested in diagnosis, in the appropriate treatment and in monitoring the progress of the disease, when appropriate, with campimetry as a great help in solving these problems.

This work deals, therefore, with some knowledge necessary for the understanding of pathologies of the optical pathway, routinely found in Ophthalmology and other specialties. Also, some interesting findings are not often found in daily practice. It is an attempt to show how this complementary exam can be useful.

It is not a complete work, nor perfect, nor does it present news, nor does it intend to exhaust the subject, much less replace what already exists. It only tries to get closer, stimulating and encourage the understanding of campimetry to facilitate the work of those who want to revive or learn a little more.

In the beginning, when I did not have a field meter, I built a flat screen myself and then acquired a dome. Then, I asked a friend, who had followed a brilliant computer career, to help me build a computerized field meter.

I provided biophysical information, techniques, and convenient parameters within Ophthalmology. After that, this friend allied himself with other experts on the subject. Then, a reasonable prototype was arrived at.

They continued to study, taking courses, and traveling abroad and managed to develop the PCLab Campimeter, visual field analyzer, which proved to be suitable, because nothing to any other existing in the market.

Today we use the Campimeter model 33FT30 NB from PCLAB as the best option, for several reasons such as its programs, its ease of purchase, its inviting price much lower than any other similar imported product, as it is a Brazilian product, of high technology, including presenting the Blue-Yellow program.

CHAPTER  1

INTRODUCTION

Campimetry

Definition – It is a psychophysical examination characterized by the analysis of the entire visual field, not only of its external contour, but of everything contained therein, to detect abnormalities corresponding to injuries that occur in sectors or segments of the optical pathway.

Included are pre-retinal lesions that are not part of the optical pathway (opacifications of the cornea, crystalline and vitreous) and even lesions of the visual cerebral cortex, therefore, pre-chiasmatic, chiasmatic and post-chiasmatic lesions.

This exam is of interest to ophthalmologists, neurologists, and clinicians. It is important to consider that various types of visual field defects are quite specific in various diseases or pathologies.

Objective – It is to evaluate the presence or absence of defects in the visual field.

Campimetry or Perimetry – The term Perimetry means measurement of the contour line of a figure or area. It is not the case, therefore, of visual field evaluation.

In the English language, the word field is translated by field and has other meanings, but there is no word fieldmetry, which would be translated by Campimetry.

The term Perimetry in the English language should be translated into Portuguese by Campimetry and not by Perimetry concerning visual field.

The English language uses a single word with different meanings in a much larger amount than ours, which, in contrast, uses many words for the same meaning (synonyms).

Campimetry indicates measurements in a field. In soccer, for example, in a field measuring 90 m x 50 m the perimeter is 90 + 50 + 90 + 50 = 280 m; but measurements of the small area, the large area, the bars, the large circle, the marking of the penalty spot, the area from which the corner kick is to be taken, etc. are excluded from the perimeter. These are measurements of the details, of the entire field, and not of the perimeter.

In the Visual Field, measurements are not exclusive to the contour line of this field, as the word perimetry indicates. Even the word campimetry, which is much more suitable for this case, does not reflect the reality of what is intended in the assessment of the visual field, but this term fits much better than perimetry.

Even intending, perforce, to perpetuate the term perimetry, which has been in use for a long time, but because of artifice, transgressing the vernacular, in an Americanized neglect, here is the suggestion of replacing the word perimetry with campimetry, which is a qualitative and quantitative measure of everything that is expressed in the entire visual field.

In this book, I will not use the term perimetry even because I am convinced of its inadequacy. I have seen many other terms in ophthalmology books and journals or not, translated from English into Portuguese almost as a disregard for our language. An example is an altitudinal defect, a word that does not exist in Portuguese, whose most adequate translation is altitudic. It would be much better if we used altitude or altitudic defects. Do not come to me to say that these neologisms are consecrated by the use to persist in the error.

My suggestion is that, gradually, we begin using more appropriate terms. Another example is the term circunlinear captured directly from English without translation, without changing anything. It is best, instead of a circumferential vessel, to call it an outlining or outlining vessel; it is much simpler and easier to understand, being more suitable within the vernacular.

Alternatively, there is no scientific or logical basis to affirm that the visual field evaluation method, in which the stimuli presented on the periphery of the screen of an analyzer, as they are a little further apart than those in the central area , characterizes what is called campimetry. This will continue to be the evaluation of everything contained in the field, as a whole, and perimetry will continue to be a measure of the contour of an area or figure; therefore, inadequate to refer to the analysis of the visual field. It is good to remember that this term is not exclusive to Ophthalmology; it belongs to Physics, Biophysics, Design, Architecture, Engineering, etc.

Since 1996, Blue & Yellow Campimetry (Short & Wavelength Computerized Campimetry - Blue & Yellow or SWAP - Short Wavelength Automated Perimetry) was introduced, which greatly improved the ability to ascertain the loss of visual field earlier in patients with suspected initial glaucoma. This test is intended to detect field losses five years earlier than conventional campimetry. Its indication is mainly: suspected glaucoma in patients with ocular hypertension without other pathologies or in patients with mild or moderate visual field defects; it is not indicated for patients with cataracts who commonly present the yellowish lens. According to Johnson, retinal neural cells are more sensitive to blue light, being the first to be affected in early glaucoma. The Blue & Yellow test looks more closely at cones sensitive to low wavelengths in the vicinity of 440 nm.

Exist other methods under observation to assess glaucomatous lesions. It is good to remember, however, that campimetry is not an exclusive exam for glaucoma.

CHAPTER  2

MORPHOLOGICAL AND PHYSIOLOGICAL BASES OF VISION

1. A light stimulus from any light-emitting object, when captured by the eye, generates an impulse ________ of an electrical nature.

2. The eye is the first transducer (transforming one form of energy into another, by changing the types of signals) in the process of visual perception, transforming radiant (luminous) energy into __________ energy forming the neural impulses.

Answers - 1: neural. 2: electric.

3. The second transduction of the visual process occurs in the visual cerebral cortex where the electrical energy of the neural impulse transforms into ________ visual.

4. Some objects emit radiant energy like a light bulb, for example. Other objects only reflect ________ that comes from other sources.

Answers - 3: sensation, 4: light.

5. The radiant energy of the sun falling on the beach sand causes a reflection of this light that is perceived by ________.

6. Many objects that do not emit light are perceived by the eye because ________ a light from another emitting source.

Answers - 5: eye. 6: reflect.

VISIBLE SPECTRUM - Only a narrow band, over the entire frequency range of electromagnetic radiation, is effective in allowing an eye response by stimulating the retina. It is exactly the range between 370 to 740 nm, called the visible spectrum. The retina cannot be stimulated by radiation outside this range.

7. The light energy propagates through electromagnetic radiation of a certain length ________.

8. Light in the form of electromagnetic waves is produced by bodies capable of emitting radiant ________.

Answers - 7: wave. 8: energy.

9. Not all electromagnetic radiation can be perceived by ________ because not all stimulate the retina.

10. There is a limit of the eye to perceive the ________ of electromagnetic radiation.

Answers - 9: eye. 10: stimuli.

11. Radio waves, radar, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays are electromagnetic radiation. Of all these, the human eye only perceives the ________.

12. Infrared rays that are emitted at low frequency are unable to stimulate the ________.

Answers - 11: visible light. 12: retina.

13. The retina also does not perceive the ________ rays, whose emission frequency is high; however, after cataract surgery these rays are partially perceived.

14. The electromagnetic radiation perceived by the eye is called the ________ spectrum.

Answers - 13: ultraviolet. 14: visible.

15. Gamma, X and UV rays are emitted more frequently than