Glaucoma is an acute or chronic condition in which there is an increase of intraocular pressure (IOP), which leads to damage of the retina and optic nerve, with resulting visual field loss. In the normal eye, IOP (10 to 21 mm Hg) exists as long as there is a balance between the production, circulation, and outflow of aqueous humor. Aqueous humor is produced in the posterior chamber ciliary processes and flows through the pupil into the anterior chamber. From the anterior chamber, it passes through the canal of Schlemm and out through the aqueous veins into the anterior ciliary veins. Increased IOP compromises blood flow to the optic nerve and retina. Tissue damage occurs as a result of the deficient blood supply and progresses from the periphery toward the fovea centralis. If IOP is left untreated, blindness results.
Chronic open-angle glaucoma (primary open-angle) is the most common form of glaucoma, accounting for 90% of all glaucoma cases. It is caused by an overproduction of aqueous humor or obstruction to its flow through the trabecular meshwork or the canal of Schlemm. The chamber angles between the iris and the cornea remain open. IOP intensifies gradually because aqueous humor cannot leave the eye at the same rate that it is produced. Acute glaucoma, also referred to as closed-angle glaucoma or narrow-angle glaucoma, is less common and, with its sudden onset, is treated as an emergency situation. Obstruction of the outflow of aqueous humor occurs by anterior displacement of the iris against the cornea, which narrows or obstructs the chamber angle. Attacks of acute glaucoma are caused by injury, pupil dilation, or stress. Secondary glaucoma occurs in other diseases of the eye when the circulation of aqueous humor is disrupted with either a decreased angle or an increased intraocular volume. Uveitis, iritis, trauma, tumors, and postsurgical procedures on the eye are common causes of secondary glaucoma. Congenital glaucoma is caused by an autosomal recessive trait that results in dysfunctional development of the trabecular meshwork through which aqueous humor flows.
Nursing care plan assessment and physical examination
Ask the patient if she or he has had recent eye surgery, trauma, or infection. Use of antihistamines can precipitate closed-angle glaucoma because antihistamines cause pupils to dilate, and this may result in obstruction of fluid flow. Family visual history can help with a diagnosis of chronic open-angle glaucoma. Because open-angle glaucoma develops slowly, the visual history should focus on foggy vision, diminished accommodation, frequent changes in eyeglass prescription, mild eye pain, headache, visual field deficits, and halos around lights.
Gentle palpation of the covered eyeball reveals a firmer globe, which has been caused by the increased IOP. Blind spots and peripheral field losses are confirmed by a visual field examination. Inspect the patient’s eyes for reddened sclera, turbid aqueous humor, and moderately dilated nonreactive pupils. Other symptoms include extreme unilateral eye pain, blurred vision, and possibly nausea and vomiting. Symptoms of congenital glaucoma include photophobia, cloudy corneas, excessive tearing, and muscle spasms around the orbital ridge (bleapharospasm).
Validate observations of anxiety, and explore coping strategies to deal with patient concerns. Grieving for the potential of vision loss or vision already lost follows the stages of denial, anger, bargaining, depression, and acceptance.
Nursing care plan primary nursing diagnosis: Sensory and perceptual alterations (visual) related to nerve fiber destruction caused by increased IOP.
Nursing care plan intervention and treatment
Glaucoma is often treated medically. Surgery is required when medications are ineffective in reducing IOP. Argon laser trabeculoplasty is preferred because it has an 80% success rate in reducing IOP. Surgical filtering treatment produces a permanent fistula from the anterior chamber and the subconjunctival space. Filtering procedures include trabeculectomy, cyclodialysis, peripheral iridectomy, sclerectomy, and ocular implantation devices such as the Molento implant.
After surgical filtering, postoperative care includes dilation and topical steroids to rest the pupil. Postoperative care after peripheral iridectomy includes cycloplegic eyedrops in only the affected eye to relax the ciliary muscle and to decrease inflammation, thus preventing adhesions. When other surgical procedures have failed, cyclocryotherapy may be performed. Parts of the ciliary body are destroyed by the freezing effect of the probe, which reduces aqueous humor production.
Blindness from glaucoma can frequently be prevented by early detection and lifelong treatment. Patients are informed that vision loss is permanent, but further vision loss may be prevented if IOP is controlled through medications or surgery.
To prevent injury that is related to reduced peripheral vision, arrange the environment to ensure safety. Place frequently used items where the patient can view them through central visual fields. Administer miotics, which cause pupillary constriction, blur vision for 1 to 2 hours after installation, and reduce adaptation to darkness. Miotics are often given four times a day to fit the patient’s schedule, or have the physician order the gel form (pilocarpine HS gel), which can be given once a day at night. Some patients benefit by the use of Ocusert, a pilocarpine time-released wafer. The wafer is inserted weekly and is helpful to patients who cannot insert eyedrops.
To minimize self-care deficits, encourage independence with activities of daily living, and assist the patient as necessary. Encourage the patient to express anxiety, grieving, and concerns about glaucoma or blindness. Listen supportively, and explore coping strategies. Reinforce compliance with the recommended treatment plan and follow-up care.
Nursing care plan discharge and home health care guidelines
To prevent increased IOP, teach the patient to avoid the following: bending at the waist, lifting heavy objects, coughing, vomiting, and straining to have a bowel movement. Note that following the medication schedule and routinely seeing the eye doctor can prevent further visual loss. Glaucoma requires strict, consistent treatment to prevent blindness.
Validate the patient’s understanding of all medications, including dosage, route, action, and side effects. Be sure the patient has the dexterity to instill eyedrops correctly. Suggest a daily calendar log to record medication use. Written guidelines may be helpful. Review the date and time of the return visit to the eye surgeon after surgery. Instruct the patient to wear an eye shield over the operated eye at night and eyeglasses during the day to prevent accidental injury. Explain the need for the patient to call the eye doctor right away if any of the following symptoms occurs: pain in the eye, shortness of breath, nausea or vomiting, loss of vision, nonreactive pupils, reddened sclera, bleeding, discharge, or tingling in the hands or feet.