9 things glaucoma patients want to know

Will Smith, OD Today, eyecare teams are strained by heavily loaded schedules and stacks of diagnostic images to review. We sometimes forget the compassion we have for patients with ocular disease when we deliver the news.

It is not realistic for patients to be prepared to respond when they are given news of a disease or disorder. Many times, patients are caught off guard at the mention of disease and assume a blank stare as their minds wonder in fear. What questions are they supposed to ask?

Instead of sending these patients home to worry and surf the tidal wave of disaster-the Internet-doctors and staff should be first-line educators. We should be prepared to provide information before patients ask.

If a patient has just been given the diagnosis of glaucoma or currently has glaucoma, stay proactive by providing answers to the questions she might ask.

1. What is glaucoma?

Glaucoma is a group of ocular diseases with various causes that ultimately are associated with progressive optic neuropathy leading to loss of visual function.¹

This definition is comprehensive because there are a multitude of causes for glaucoma, not just high intraocular pressure (IOP) and the disease must be progressive in nature, not simply a one-time loss of neural tissue, like in the case of a stroke. High IOP is one of the strongest risk factors for disease;² therefore, it is a variable that should always monitored.

One of my professors described IOP and glaucoma as water draining through a sink. The eye produces water (aqueous) and escapes from the eye through a drain. A sink works with water flowing from a faucet and draining. If no one turns off the faucet, water builds up in the sink. If there is a problem with the drain, water builds up in the sink. This buildup of water increases pressure just like in a closed system, i.e., the eye.

2. What are the signs and symptoms of glaucoma?

The disease may manifest without any pain or noticeable vision loss. This is why glaucoma has been called the silent thief. In fact, most patients will never experience significant signs or symptoms of glaucoma.

Related: 5 things about glaucoma care that frustrate me

In severe cases of ocular hypertension or when IOP is elevated up to 40 mm Hg or even 60 mm Hg, patients my experience ocular pain, light sensitivity, redness, and headache. One patient with an IOP of 74 mm Hg said, “Doc, please get this rat out of my head.” He was describing the severe head pain that is associated with high IOP.

Angle closure glaucoma may cause blurred vision or vision loss; this may be temporary or permanent. Refer back to the sink analogy. If the drain becomes clogged or closed, the IOP can rise rapidly and cause symptomatic nerve damage.

3. Will I go blind from glaucoma?

To tackle this question, we must first define blindness. The Centers for Disease Control and Prevention (CDC) defines legal blindness as central visual acuity of 20/200 or less in the better eye with the best possible correction and/or a visual field of 20 degrees or less.³ Most studies which look to answer the aforementioned question use the legal blindness criterion.

Based on legal blindness criterion alone, we look to two major studies.^4,5 They reported that 12.4 percent and 22 percent, respectively, of patients with glaucoma will go blind in both eyes. Each study looked at a subset of patients from the 1980s and earlier.

Another study looked at patients diagnosed between 1981 and 2000 compared with patients diagnosed between 1965 and 1980 in the same geographic location.⁶ According to this study, the probability of glaucoma-related blindness in at least one eye at 20 years decreased from 25.8 percent for subjects diagnosed between 1965 and 1980 to 13.5 percent for subjects diagnosed between 1981 and 2000. Better diagnostic equipment and improved medical and surgical treatments have dramatically improved patient outcomes.

What legal blindness does not address is patients’ ability to perform vision-related activities or patients’ quality of life (QoL). A clinician’s ultimate goal is to address patients’ concerns, which usually are centered on improving or at least maintaining their ability to function. Several studies have been developed to better assess these concerns. One investigator found patients with good visual acuity can report unfavorable vision due to decreased visual field and poor contrast sensitivity. This informs us that there are more important factors to people being able to “see” vs. being able to function.^7,8

4. I lowered my blood pressure, so is my eye pressure low?

Blood supply to the eye comes from the carotid artery which runs along the neck. The internal portion of this supplies the ophthalmic artery which delivers most of the eye’s blood. Some of this blood supply goes to make aqueous humor from the ciliary body-think water from the faucet.

Low blood pressure yields low aqueous production; however, homeostasis (the body’s equalizer) keeps the body regulated. When a person exercises, his blood pressure will rise, and so might his IOP. The body is able to compensate for this and return eye pressure to its usual level.

In a patient with chronic high blood pressure, this could lead to decreased circulation or poor blood supply to the eye. This lack of blood supply to the eye can cause glaucoma, even with normal IOP.

Blood pressure does play a role in glaucoma, but it does not directly correlate with an individual’s eye pressure.

5. What are the best treatments for glaucoma?

At this time, the main goal with treating glaucoma is decreasing IOP. Most major glaucoma studies have proven that by lowering the IOP, this will delay or prevent glaucomatous progression or conversion; even in patients with normal tension glaucoma.^2,9-11 IOP can be lowered with topical drop medication, laser treatment, and surgical procedures.

Topical medications are considered first line of treatment in the United States. They show good efficacy by lowering IOP 20 to 30 percent. There is a variable side effect profile with drops, but most patients tolerate them well. One downfall with instilling drops is patient compliance. Like anything else that must be performed up to several times a day, people forget. Missing a dose could cause IOP to spike.

Related: How MIGS are changing glaucoma treatment

Laser procedures to decrease IOP are roughly equivalent in safety and efficacy to medication with one drug. Many studies report that selective laser trabeculoplasty has few side effects, eliminates many compliance concerns, and saves money.¹² Arguably laser could be used first line for many glaucomas.^7,13 IOP decrease is similar to that of medications, and some studies report it lasts 30 months and up to 5 years.^14,15 One challenge with laser is some patients are afraid of a laser procedure and will opt for other treatments.

Many surgical procedures are available now. Some are more invasive than others, but all involve opening the eye. Minimally invasive glaucoma surgery (MIGS) has gained popularity over the past few years. These procedures use a microscopic-sized tool and tiny incisions to help lower IOP. While these procedures reduce the incidence of complications, they may not be as effective as more invasive procedures such as trabeculectomy and shunts. MIGS are options for patients with mild to moderate glaucoma.

The idea behind all glaucoma surgeries is to create a channel for fluid to drain from the inside of the eye to underneath the outer membrane of the eye (i.e., conjunctiva). With the exception of MIGS, glaucoma surgeries are typically reserved for severe glaucoma cases where other therapies have failed.

6. Can I use marijuana to treat my glaucoma?

Marijuana does lower IOP.¹⁶ Unfortunately, IOP sits at therapeutic range for three to four hours, and not everyone -only 60 percent of individuals-experience a pressure reduction. This means patients would need to dose themselves almost every 4 hours, even while asleep.

Regarding smoking marijuana vs. consuming edibles, the long-term toxic effects have been well studied.^17,18 Studies found that drug absorption is maximum with smoking, and both smoking and edibles yield euphoric effects.¹⁹

There has been development of aqueous-based solutions for topical administration to the eye. A study reported the solution retains IOP-reducing activity without euphoric effects.¹⁶

Marijuana alone cannot compete with other available treatments at this time. Marijuana may offer many health benefits and great potential, but more research is needed to capture therapeutic components without side effects.

7. What if I miss a dose?

Instilling eye drops consistently reduces the likelihood of pressure fluctuation (diurnal variation). Experts found that 67 percent of peak IOP occurs outside of typical office hours.²⁰ Inconsistent use of drops will vary IOP and has been proven to be detrimental to glaucoma.²¹

Everyone is human, and staying compliant with the drops is important. Instill the drops as soon as patients remember, even if it seems like they are doubling up within a few hours.

8. How do you get glaucoma?

Glaucoma is not contagious. It develops from many different risk factors.

As mentioned earlier, high IOP is the number-one risk factor for disease progression. Other risk factors include thin corneas, sleep apnea, history of eye injury, family history, and African American or Hispanic race.

About 50 percent of glaucoma cases are thought to be genetic.²² If a parent has glaucoma, children are five times more likely to develop glaucoma. If a sibling has glaucoma, there is a 10 times greater risk for disease.²³

Many risk factors cannot be controlled; however, some can. The controllable risk factors include: smoking, lack of exercise, diabetes, and high blood pressure.²⁴

Related: Medically managing glaucoma

9. What resources are available for patients with impaired vision?

Some patients with glaucoma and other ocular disease will lose vision no matter how compliant they are with treatments. Taking advantage of available resources can improve quality of life even if treatment cannot prevent vision loss.

For veterans, the Department of Veterans Affairs (VA) has the most resources available for visually impaired individuals. They offer many low vision devices which may assist in daily living activities. For example, devices can magnify text, help a patient write a check, and sound an alarm when to stop pouring hot beverages to avoid burns.

In addition to devices, the VA offers services to improve the household, such as helping people to cook for themselves.

Low vision devices and services may be available at other clinics or institutions. Most optometry schools offer these services as well as non-profit institutions such as Lighthouse for the Blind.

Transportation can be a big concern when someone becomes visually impaired. These individuals lose independence and may become depressed. Many cities have public transportation, for which visually impaired people are often offered a discount or free use. Some cities may offer free ride service for disable individuals. Uber, a ride hailing service similar to taxis, recently integrated a voiceover app which helps visually impaired people hail a ride.

Related: How oral and dental hygiene plays a role in glaucoma

Many resources offer entertainment. Audiobooks are loaned for free or a small fee at libraries. News outlets such as National Public Radio (NPR) are available, and many cities transcribe local newspaper to audio. Community centers may offer recreational programs such as bowling, yoga, and ball sports.

Other resources may be available in different local areas.

Wrapping up

It is rare patients come without questions, and what better source for them to trust than their eyecare team. Take opportunities to help educate patients-this will help to reassure patients as well as build patient confidence you and in the practice.

Work with colleagues and doctors to keep patients as informed as possible.

References

1. Fingeret, Murray. Optometric Clinical Practice Guideline. Care of the Patient with Open Angle Glaucoma. American Optometric Association. Available at: https://www.aoa.org/documents/optometrists/CPG-9.pdf. Accessed 2/25/18.

2. Keltner JL, Johnson CA, Cello KE, Bandermann SE, Fan J, Levine RA, Kass MA, Gordon MO; Ocular Hypertension Treatment Study Group. Visual field quality control in the Ocular Hypertension Treatment Study (OHTS). J Glaucoma. 2007 Dec;16(8):665-9.

3. Centers for Disease Control and Prevention. Blindness and Vision Impairment. Available at: https://www.cdc.gov/healthcommunication/toolstemplates/entertainmented/tips/Blindness.html. Accessed 2/25/18.

4. Grant WM, Burke JF Jr. Why do some people go blind from glaucoma? Ophthalmology. 1982 Sep;89(9):991-8.

5. Hattenhauer MG, Johnson DH, Ing HH, Herman DC, Hodge DO, Yawn BP, Butterfield LC, Gray DT. The probability of blindness from open-angle glaucoma. Ophthalmology. 1998 Nov;105(11):2099-104.

6. Malihi M, Moura Filho ER, Hodge DO, Sit AJ. Long-term trends in glaucoma-related blindness in Olmsted County, Minnesota. Ophthalmology. 2014;121:134.

7. National eye institute’s Visual Functioning Questionnaire (NEI-VFQ-25), Assessment of function related to vision (AFREV), and Compressed Assessment.of ability Related to Vision (CAARV).

8. Ekici F, Loh R, Waisbourd M, Sun Y, Martinez P, Nayak N, Wizov SS, Hegarty S, Hark LA, Spaeth GL.Relationships between measures of the ability to perform vision-related activities, vision-related quality of life, and clinical findings in patients with Glaucoma. JAMA Ophthalmol. 2015 Dec;133(12):1377-85.

9. Leske MC, Heijl A, Hussein M, Bengtsson B, Hyman L, Komaroff E; Early Manifest Glaucoma Trial Group. Factors for glaucoma progression and the effect of treatment: the early manifest glaucoma trial. Arch Ophthalmol. 2003 Jan;121(1):48-56.

10. The Advanced Glaucoma Intervention Study (AGIS): 7. The relationship between control of intraocular pressure and visual field deterioration. The AGIS Investigators. Am J Ophthalmol. 2000 Oct;130(4):429-40.

11. Comparison of glaucomatous progression between untreated patients with normal-tension glaucoma and patients with therapeutically reduced intraocular pressures. Collaborative Normal-Tension Glaucoma Study Group. Am J Ophthalmol. 1998 Oct;126(4):487-97.

12.The Glaucoma Laser Trial (GLT). 2. Results of argon laser trabeculoplasty versus topical medicines. The Glaucoma Laser Trial Research Group. Ophthalmology. 1990 Nov;97(11):1403-13.

13. Waisbourd M, Katz LJ. Selective laser trabeculoplasty as a first-line therapy: a review. Can J Ophthalmol. 2014 Dec;49(6):519-22.

14. The Advanced Glaucoma Intervention Study (AGIS): 4. Comparison of treatment outcomes within race. Seven-year results. Ophthalmology. 1998 Jul;105(7):1146-64.

15. Migdal C, Gregory W, Hitchings R. Long-term functional outcome after early surgery compared with laser and medicine in open-angle glaucoma. Ophthalmology. 1994 Oct;101(10):1651-6; discussion 1657.

16. Green K. Marijuana smoking vs cannabinoids for glaucoma therapy. Arch Ophthalmol. 1998 Nov;116(11):1433-7.

14. 17. Graham IDP. Cannabis and Health. Orlando, FL:Academic Press Inc; 1976.

18. Rosenkrantz H, Fleischman RW. Effects of cannabis on lungs. In: Nahas GG, Paton WDM eds. Marihuana: Bilolgical Effects. Elmsford, NY:Pergamon Press Inc;1979:279-299.

19. Dewey WL. Cannabinoid pharmacology. Parmoacol Reb. 1986 Jun;38(2):151-78.

20. Mosaed S, Liu JH, Weinreb RN. Correlation between office and peak nocturnal intraocular pressures in healthy subjects and glaucoma patients. Am J Ophthalmol. 2005 Feb;139(2):320-4.

21. Gross RL, Peace JH, Smith SE, Walters TR, Dubiner HB, Weiss MJ, Ochsner KI. Duration of IOP reduction with travoprost BAK-free solution. J Glaucoma. 2008 Apr-May;17(3):217-22.

22. Wolfs RC, Klaver CC, Ramrattan RS, van Duijn CM, Hofman A, de Jong PT. Genetic risk of primary open-angle glaucoma. Population-based familial aggregation study. Arch Ophthalmol. 1998 Dec;116(12):1640-5.

23. Leske MC, Connell AM, Schachat AP, Hyman L. The Barbados Eye Study. Prevalence of open angle glaucoma. Arch Ophthalmol. 1994 Jun;112(6):821-9.

24. Bonomi L, Marchini G, Marraffa M, Bernardi P, Morbio R, Varotto A. Vascular risk factors for primary open angle glaucoma: the Egna-Neumarkt Study. Ophthalmology. 2000 Jul;107(7):1287-93.

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