Glaucoma is caused by increased pressure in the eye due to a backup of fluid that over time damages the optic nerve. It is often asymptomatic until vision is impaired. The main types are primary open-angle glaucoma, which is the most common, as well as normal tension glaucoma, angle-closure glaucoma, and others. Treatment aims to lower pressure through medication or surgery to prevent further vision loss.
This was a lecture in the course "Significant Medical Conditions in Seniors" presented at Peer Learning in Chapel Hill, NC, USA in 2016 by Michael C. Joseph, MD, MPH.
Glaucoma is a group of eye conditions that damage the optic nerve. The optic nerve sends visual information from your eye to your brain and is vital for good vision. Damage to the optic nerve is often related to high pressure in your eye. But glaucoma can happen even with normal eye pressure.
Glaucoma can occur at any age but is more common in older adults. It is one of the leading causes of blindness for people over the age of 60.
Many forms of glaucoma have no warning signs. The effect is so gradual that you may not notice a change in vision until the condition is in its later stages.
It's important to have regular eye exams that include measurements of your eye pressure. If glaucoma is recognized early, vision loss can be slowed or prevented. If you have glaucoma, you'll need treatment or monitoring for the rest of your life.
Products & Services
Book: Mayo Clinic Guide to Better Vision
Symptoms
The symptoms of glaucoma depend on the type and stage of your condition.
Open-angle glaucoma
No symptoms in early stages
Gradually, patchy blind spots in your side vision. Side vision also is known as peripheral vision
In later stages, difficulty seeing things in your central vision
Acute angle-closure glaucoma
Severe headache
Severe eye pain
Nausea or vomiting
Blurred vision
Halos or colored rings around lights
Eye redness
Normal-tension glaucoma
No symptoms in early stages
Gradually, blurred vision
In later stages, loss of side vision
Glaucoma in children
A dull or cloudy eye (infants)
Increased blinking (infants)
Tears without crying (infants)
Blurred vision
Nearsightedness that gets worse
Headache
Pigmentary glaucoma
Halos around lights
Blurred vision with exercise
Gradual loss of side vision
When to see a doctor
If you experience symptoms that come on suddenly, you may have acute angle-closure glaucoma. Symptoms include severe headache and severe eye pain. You need treatment as soon as possible. Go to an emergency room or call an eye doctor's (ophthalmologist's) office immediately.Causes
Glaucoma develops when the optic nerve becomes damaged. As this nerve gradually deteriorates, blind spots develop in your vision. For reasons that doctors don't fully understand, this nerve damage is usually related to increased pressure in the eye.
Elevated eye pressure happens as the result of a buildup of fluid that flows throughout the inside of the eye. This fluid also is known as the aqueous humor. It usually drains through a tissue located at the angle where the iris and cornea meet. This tissue also is called the trabecular meshwork. The cornea is important to vision because it lets light into the eye. When the eye makes too much fluid or the drainage system doesn't work properly, eye pressure may increase.
Open-angle glaucoma
This is the most common form of glaucoma. The drainage angle formed by the iris and cornea remains open.
Central and Peripheral Vision & their DiseasesHuzaifa Zahoor
The act or power of seeing
The special sense by which the qualities of an object (such as color, luminosity, shape, and size) constituting its appearance are perceived through a process in which light rays entering the eye are transformed by the retina into electrical signals that are transmitted to the brain via the optic nerve.
Types of Vision
Central Vision
Peripheral Vision
Disease of Vision
Central Vision Loss
Peripheral Vision Loss
some people are affected with this problem they want to know about the glaucoma causes, risk factor, pathophysiology, signs and symptoms, treatment and complication, etc and they get more knowledge and they will avoid the complication especially loss of vision.
Glaucoma is a group of eye diseases that has one thing in common: progressive (increasing) damage to the vision nerve (optic nerve) that connects the eyeball to the brain.
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
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
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
1. Glaucoma is caused by a number of different eye diseases that in most cases
produce increased pressure within the eye. This elevated pressure is caused by a
backup of fluid in the eye. Over time, it causes damage to the optic nerve. Through
early detection, diagnosis and treatment, you and your doctor can help to preserve
your vision.
Think of your eye as a sink, in which the faucet is always running and the drain is
always open. The aqueous humor is constantly circulating through the anterior
chamber. It is produced by a tiny gland called the ciliary body that is situated
behind the iris. It flows between the iris and the lens, and after nourishing the
cornea and lens, flows out through a very tiny spongy tissue called the trabecular
meshwork, which is only one-fiftieth of an inch wide and serves as the drain of the
eye. The trabecular meshwork is situated in the angle where the iris and cornea
2. meet. When this drain becomes clogged, aqueous cannot leave the eye as quickly
as it is produced, causing the fluid to back up. But because the eye is a closed
compartment, your `sink´ doesn´t overflow, and instead the backed up fluid causes
increased pressure to build up within the eye. We call this open (wide) angle
glaucoma.
To understand how this increased pressure affects the eye, think of your eye as a
balloon. When too much air is blown into the balloon, the pressure builds, causing
it to pop. But the eye is too strong to pop. Instead, it gives at the weakest point,
which is the site in the sclera at which the optic nerve leaves the eye.
As we mentioned earlier, the optic nerve is the part of the eye that carries visual
information to the brain. It is made up of over one million nerve cells, and while
each cell is several inches long, it is extremely thin -- about one twenty-thousandth
of an inch in diameter. When the pressure in the eye builds, the nerve cells become
compressed, causing them to become damaged and to eventually die. The death of
these cells results in permanent visual loss. Early diagnosis and treatment of
glaucoma can help prevent this from happening.
The Eye and How It Works
The first step in understanding glaucoma is to know a few basic facts about the eye
and how it works. Once you have this information, you will be better able to discuss
your condition and treatment with your eye doctor. Working together, you and your
doctor will be able to act as a team to protect your vision
Think of Your Eye as a Camera
Like a camera, the eye captures information about shape, color, and movement,
and relays it in the form of impulses to the brain. The brain then processes this
information into the "pictures" we see. Let us look at the various parts of our
camera -- the eye.
3. The outer layer of the eyeball is called the sclera. The sclera is a thin, yet tough,
leathery protective shell which is the "white of the eye." The front portion of the
shell is called the cornea. The cornea is a clear tissue through which light rays
enter the eye. The cornea is much like the lens of a camera, providing the eye with
much of its light focusing power.
The colored portion of the eye is called the iris. The iris not only determines
whether your eyes appear blue or brown, but functions like the diaphragm of a
camera. The iris contains muscles which control the size of the pupil, regulating
the amount of light allowed to enter the eye.
The pupil, which is the dark-colored area in the center of the iris, opens and closes
depending upon how much light is present. When there is a great deal of light, like
a bright, sunny day outdoors, the iris constricts the pupil, or makes it smaller. This
limits the amount of light which passes through the pupil to the retina at the back
of the eye. The retina may be thought of as the camera´s film. When there is little
or no light, the iris dilates the pupil, widening it so that more light can enter the
eye.
The lens, which is behind the iris, adjusts its shape and thickness to focus the
image onto the retina. The retina then delivers the image to the brain via nerve
signals sent through the optic nerve to the brain, which processes these signals into
a "picture," or visual image.
The interior of the eye is filled with fluid. A gel-like substance called vitreous fills
the center region of the eye. This region is called the vitreous cavity.
The anterior chamber, or front compartment of the eye, is bounded by the cornea,
iris, pupil, and lens. It is filled with a watery fluid called the aqueous humor. This
fluid nourishes the cornea and the lens, providing them with oxygen and vital
nutrients. The aqueous humor also provides the necessary pressure to help
maintain the shape of the eye. We call this pressure the intraocular pressure (IOP).
As explained on the next page, maintaining the right amount of pressure within the
eye is very important to protecting your vision. Measuring the IOP is one of the
ways in which your eye doctor tests for glaucoma.
4. TYPES OF GLAUCOMA
There are a variety of different types of glaucoma. The most common forms are:
Primary Open-Angle Glaucoma
Normal Tension Glaucoma
Angle-Closure Glaucoma
Acute Glaucoma
Pigmentary Glaucoma
Exfoliation Syndrome
Trauma-Related Glaucoma
Let us look at each of these forms of glaucoma.
Primary Open-Angle Glaucoma (POAG)
Approximately one percent of all Americans have this form of glaucoma, making it
the most common form of glaucoma in our country. It occurs mainly in the over-50
age group.
There are no symptoms associated with POAG. The pressure in the eye slowly
rises and the cornea adapts without swelling. If the cornea were to swell, which is
usually a signal that something is wrong, symptoms would be present. But because
this is not the case, this disease often goes undetected. It is painless, and the patient
often does not realize that he or she is slowly losing vision until the later stages of
the disease. However, by the time the vision is impaired, the damage is
irreversible.
In POAG, there is no visible abnormality of the trabecular meshwork. It is
believed that something is wrong with the ability of the cells in the trabecular
meshwork to carry out their normal function, or there may be fewer cells present as
a natural result of getting older. Some believe it is due to a structural defect of the
eye´s drainage system. Others believe it is caused by an enzymatic problem. These
5. theories, as well as others, are currently being studied and tested at numerous
research centers across the country.
Glaucoma is really about the problems that occur as a result of increased IOP. The
average IOP in a normal population is 14-16 millimeters of mercury (mmHg). In a
normal population pressures up to 20 mmHg may be within normal range. A
pressure of 22 is considered to be suspicious and possibly abnormal. However, not
all patients with elevated IOP develop glaucoma-related eye damage. What causes
one person to develop damage while another does not is a topic of active research.
As we mentioned earlier, this increased pressure can ultimately destroy the optic
nerve cells. Once a sufficient number of nerve cells are destroyed, `blind spots´
begin to form in the field of vision. These blind spots usually develop first in the
peripheral field of vision, the outer sides of the field of vision. In the later stages,
the central vision, which we experience as `seeing,´ is affected. Once visual loss
occurs, it is irreversible because once the nerve cells are dead, nothing can
presently restore them. Later on, we will talk about the many ways your eye doctor
can detect glaucoma in its earliest stages -- before any visual damage occurs.
POAG is a chronic disease. It may be hereditary. There is no cure for it at present,
but the disease can be slowed or arrested by treatment. Since there are no
symptoms, many patients find it difficult to understand why lifelong treatment with
expensive drugs is necessary, especially when these drugs are often bothersome to
take and have a variety of side effects.
Taking medications regularly, as prescribed, is crucial to preventing vision-
threatening damage. That is why it is important for you to discuss these side effects
with your doctor. The two of you need to act as a `team´ in the battle against
glaucoma. Later on, we will discuss the medications commonly prescribed and
their side effects.
Normal Tension Glaucoma
Normal-tension glaucoma, also known as low-tension glaucoma, is characterized
by progressive optic nerve damage and visual field loss with a statistically normal
intraocular pressure. This form of glaucoma, which is being increasingly
6. recognized, may account for as many as one-third of the cases of open-angle
glaucoma in the United States.
Normal-tension glaucoma is thought to be related, at least in part, to poor blood
flow to the optic nerve, which leads to death of the cells that carry impulses from
the retina to the brain. In addition, these eyes appear to be susceptible to pressure-
related damage even in the high normal range, and therefore a pressure lower than
normal is often necessary to prevent further visual loss.
Research in the field of optic nerve blood flow and its role in glaucoma is a source
of much excitement at the present time, and hopefully will lead to new methods of
treating this disorder. Since the best therapy for normal-tension glaucoma is largely
unknown, much attention is being given to a study known as the International
Collaborative Low Tension Glaucoma Protocol.
Angle-Closure Glaucoma
Angle-closure glaucoma affects nearly half a million people in the United States.
There is a tendency for this disease to be inherited, and often several members of a
family will be afflicted. It is most common in people of Asian descent and people
who are farsighted.
In people with a tendency to angle-closure glaucoma, the anterior chamber is
smaller than average. As mentioned earlier, the trabecular meshwork is situated in
the angle formed where the cornea and the iris meet. In most people, this angle is
about 45 degrees. The narrower the angle, the closer the iris is to the trabecular
meshwork. As we age, the lens routinely grows larger. The ability of aqueous
humor to pass between the iris and lens on its way to the anterior chamber becomes
decreased, causing fluid pressure to build up behind the iris, further narrowing the
angle. If the pressure becomes sufficiently high, the iris is forced against the
trabecular meshwork, blocking drainage, similar to putting a stopper over the drain
of a sink. When this space becomes completely blocked, an angleclosure glaucoma
attack (acute glaucoma) results.
7. Acute Glaucoma
Unlike POAG, where the IOP increases slowly, in acute angle-closure, it increases
suddenly. This sudden rise in pressure can occur within a matter of hours and
become very painful. If the pressure rises high enough, the pain may become so
intense that it can cause nausea and vomiting.
The eye becomes red, the cornea swells and clouds, and the patient may see haloes
around lights and may experience blurred vision.
An acute attack is an emergency condition. If treatment is delayed, eyesight can be
permanently destroyed. Scarring of the trabecular meshwork may occur and result
in chronic glaucoma, which is much more difficult to control. Cataracts may also
develop. Damage to the optic nerve may occur quickly and cause permanently
impaired vision.
Many of these sudden `attacks´ occur in darkened rooms, such as movie theaters. If
you recall, darkened environments cause the pupil to dilate, or increase in size.
When this happens, there is maximum contact between the eye´s lens and the iris.
This further narrows the angle and may trigger an attack. But the pupil also dilates
when one is excited or anxious. Consequently, many acute glaucoma attacks occur
during periods of stress. A variety of drugs can also cause dilation of the pupil and
lead to an attack of glaucoma. These include anti-depressants, cold medications,
antihistamines, and some medications to treat nausea.
Acute glaucoma attacks are not always full blown. Sometimes a patient may have a
series of minor attacks. A slight blurring of vision and haloes (rainbow-colored
rings around lights) may be experienced, but without pain or redness. These attacks
may end when the patient enters a well lit room or goes to sleep -- two situations
which naturally cause the pupil to constrict, thereby allowing the iris to pull away
from the drain.
8. An acute attack may be stopped with a combination of drops that constrict the
pupil and drugs that help reduce the eye´s fluid production. As soon as the IOP has
dropped to a safe level, your ophthalmologist will perform a laser iridotomy. A
laser iridotomy is an outpatient procedure in which a laser beam is used to make a
small opening in the iris. This allows the fluid to flow more freely. Drops will be
used to anesthetize your eye and there is no pain involved. The entire procedure
should take less than thirty minutes. Laser surgery may be performed
prophylactically on the other eye, as well. Since it is common for both eyes to
suffer from narrowed angles, operating on the unaffected eye is done as a
preventive measure. Routine examinations using a technique called gonioscopy
can predict one´s chances of having an acute attack. A special lens that contains a
mirror is placed lightly on the front of the eye and the width of the angle examined
visually. Patients with narrow angles can be warned of early symptoms, so that
they can seek immediate treatment. In some cases, laser treatment is recommended
as a preventive measure.
Not all angle-closure glaucoma sufferers will experience an acute attack. Instead,
some may develop what is called chronic angle-closure glaucoma. In this case, the
iris gradually closes over the drain, causing no overt symptoms. When this occurs,
scars slowly form between the iris and the drain and the IOP will not rise until
there is a significant amount of scar tissue formed -- enough to cover the drainage
area. If the patient is treated with medication, such as pilocarpine, an acute attack
may be prevented, but the chronic form of the disease may still develop.
Pigmentary Glaucoma
Pigmentary glaucoma is a type of inherited open-angle glaucoma that develops
more frequently in men than in women. It most often begins in the twenties and
thirties, which makes it particularly dangerous to a lifetime of normal vision.
Nearsighted patients are more typically afflicted. The anatomy of the eyes of these
patients appears to play a key role in the development of this type of glaucoma.
Let us examine why.
9. Myopic (nearsighted) eyes have a concave-shaped iris which creates an unusually
wide angle. This causes the pigment layer of the eye to rub on the lens. This
rubbing action causes the iris pigment to shed into the aqueous humor and onto
neighboring structures, such as the trabecular meshwork. Pigment may plug the
pores of the trabecular meshwork, causing it to clog, and thereby increasing the
IOP.
Miotic therapy is the treatment of choice, but these drugs in drop form can cause
disabling visual blurring in younger patients.
Fortunately, a slow-release form is available. We´ll discuss these drugs and their
side effects in detail later on in this guide. Laser iridotomy is presently being
investigated in the treatment of this disorder.
Exfoliation Syndrome
This common cause of glaucoma is found everywhere in the world, but is most
common among people of European descent. In about 10% of the population over
age 50, a whitish material, which upon slit-lamp examination looks somewhat like
tiny flakes of dandruff, builds up on the lens of the eye. This exfoliation material is
rubbed off the lens by movement of the iris and at the same time, pigment is
rubbed off the iris. Both pigment and exfoliation material clogs the trabecular
meshwork, leading to IOP elevation, sometimes to very high levels.
Exfoliation syndrome can lead to both open-angle glaucoma and angle-closure
glaucoma, often producing both kinds of glaucoma in the same individual. Not all
persons with exfoliation syndrome develop glaucoma. However, if you have
exfoliation syndrome, your chances of developing glaucoma are about six times as
high than if you don’t have it. It often appears in one eye long before the other, for
unknown reasons. If you have glaucoma in one eye only, this is the most likely
cause. It can be detected before the glaucoma develops; so that you can be more
carefully observed and minimize your chances of vision loss.
10. Trauma-Related Glaucoma
A blow to the eye, chemical burn, or penetrating injury may all lead to the
development of glaucoma, either acute or chronic. This can be due to a mechanical
disruption or physical change within the eye´s drainage system. It is therefore
crucial for anyone who has suffered eye trauma to have check-ups at regular
intervals.
Who is at Risk?
Everyone should be concerned about glaucoma and its effects. It is important for
each of us, from infants to senior citizens, to have our eyes checked regularly,
because early detection and treatment of glaucoma are the only way to prevent
vision impairment and blindness. There are a few conditions related to this disease
which tend to put some people at greater risk:
People over the age of 45.
While glaucoma can develop in younger patients, it occurs more frequently
as we get older.
People who have a family history of glaucoma.
Glaucoma appears to `run´ in families. The tendency for developing
glaucoma may be inherited. However, just because someone in your family
has glaucoma does not mean that you will necessarily develop the disease.
People with abnormally high intraocular pressure (IOP).
High IOP is the most important risk factor for glaucomatous damage.
People of African descent.
African-Americans have a greater tendency for developing primary open-
angle glaucoma than do people of other races.
People who have:
Diabetes
Myopia (nearsightedness)
Regular, long-term Steroid/Cortisone use
A previous eye injury
11. DIAGNOSING GLAUCOMA
Your eye doctor has a variety of diagnostic tools that aid in determining whether or
not you have glaucoma -- even before you have any symptoms. Let us explore these
tools and what they do.
The Tonometer
The Tonometer measures the pressure in the eye. If your doctor were to use
applanation tonometry, your eye would be anesthetized with drops. Then, you
would sit at the slit lamp, and a plastic prism would lightly push against your eye
in order to measure your IOP. In air tonometry a puff of air is sent onto the cornea
to take the measurement. Since this instrument does not come in direct contact
with your eye, no anesthetic eye drops are required.
Visual Field Test
Testing your visual field lets your doctor know if and how your field of vision has
been affected by glaucoma. The visual field is an important measure of the extent
of damage to your optic nerve from increased IOP. There are several methods of
examination available to your doctor.
In computerized visual field testing you will be asked to place your chin on a stand
that appears before a computerized screen. Whenever you see a flash of light
appear, you will be asked to press a button. At the end of this test, your doctor will
receive a printout of your field of vision. Another test that is similar is the
Goldmann perimeter. However, in this test, no computer is used. The examiner
records your answers whenever you indicate that the light is in view.
Ophthalmoscopy
Using an instrument called an ophthalmoscope; your eye doctor can look directly
through the pupil at the optic nerve. Its color and appearance can indicate whether
or not damage from glaucoma is present and how extensive it is.
TREATING GLAUCOMA
Glaucoma can be treated with eye drops, pills, laser surgery, eye operations, or a
combination of methods. The whole purpose of treatment is to prevent further loss
12. of vision. This is imperative as loss of vision due to glaucoma is irreversible.
Keeping the IOP under control is the key to preventing loss of vision from
glaucoma. Your doctor has several options for doing so. They include:
Eye drops
All eye drops may cause a burning or stinging sensation at first. This is often due
to the antibacterial agent present in the drop solution and not due to the drug itself.
While it can be uncomfortable, the discomfort lasts for only a few seconds.
It is important that you take your medication exactly as it is prescribed if you are
to control your IOP. For example, drops which are prescribed four times a day
usually have a `duration of action´ of six hours. By taking these drops four times
spaced through your waking hours, you ensure that you are covered by the drug´s
effectiveness for a full 24- hour period.
Since eye drops are absorbed into the bloodstream, it is important that you tell
your doctor about all other medications you are currently taking. Some drugs can
be dangerous when mixed with other medications. Ask your doctor and/or
pharmacist if the medications you are taking together are safe. To minimize
absorption into the bloodstream and maximize the amount of drug absorbed into
the eye, close your eyes for one to two minutes after administering your drops and
press lightly against the nasal corner of your eyelids to close the tear duct that
drains into the nose.
13.
14. * While every drug has some potential side effects, it is important to note that
many patients experience NO side effects at all.
Pills
Sometimes, drops are not enough to control IOP. When this is the case, pills may
be prescribed in addition to drops. These pills, which have more side effects than
drops do, also serve to turn down the eye´s faucet and lessen the production of
fluid in the eye. The medication is usually taken from two to four times daily. It is
important to share this information with your other doctors. By doing so, they can
best prescribe medications for you which will not cause potentially dangerous
interactions.
The following are some commonly prescribed carbonic anhydrase inhibitors and
their more common side effects.
15. SURGICAL PROCEDURES
When medication does not achieve the desired results, or when it has intolerable
side effects, your ophthalmologist may suggest surgery.
Laser Surgery
Laser surgery has become increasingly popular as an intermediate step between
drugs and traditional surgery. The most common type performed for open-angle
glaucoma is called trabeculoplasty. This procedure takes between ten and twenty
minutes, is painless, and can be performed in either a doctor´s office or in an
outpatient facility. The laser beam (a high energy light beam) is focused upon the
eye´s drain. Contrary to what most people think, the laser does not burn a hole
through the eye. Instead, its intense heat causes some areas of the eye´s drain to
shrink, resulting in adjacent areas stretching open and permitting the fluid to drain
more easily.
You may go home and resume normal activities following surgery. Your doctor
should check your IOP one to two hours later. After this procedure, nearly eighty
percent of all patients respond well enough to be able to avoid or delay surgery.
While it may take a few weeks to see the full pressure-lowering effect of this
procedure, during which time you may have to continue taking your medication,
many patients are eventually able to discontinue some of their medications. This,
however, is not true in all cases. Your doctor is the best judge of determining
whether or not medication is still necessary for you. Cataracts do not occur after
laser surgery and complications are minimal, which is why this has become
increasingly popular.
Traditional Surgery
The most common of these operations is called a trabeculectomy. In this
procedure, the surgeon removes a small section of the trabecular meshwork -- the
eye´s drain. This allows the aqueous humor to drain more easily, reducing the
pressure in the eye. This procedure is usually done under local anesthesia either as
an outpatient or with a brief hospital stay. As your doctor will want to see you on
the day after the operation to check both your vision and ocular pressure, some
16. prefer that you remain in the hospital. It is important to note that your eyes may not
have their normal visual acuity for several weeks following this procedure.
Although trabeculectomy is a relatively safe surgical procedure, about one-third of
patients develop cataracts within five years of surgery. After trabeculectomy, most
patients are able to discontinue all anti-glaucoma medications. Perhaps ten to
fifteen percent of patients require additional surgery.
Routine eye exams are vital for protecting the health of your
eyes. If your ophthalmologist or optometrist detects glaucoma,
early treatment can help prevent the loss of your vision.