Ophthalmic topical agents play an intricate role in diagnostic procedures and examinations for ocular deficiencies. Like most medications, safe practices are essential to effective patient care. This includes proper patient counseling of expected side effects and safe storage of medications to prevent patient access.

Common diagnostic topical agents include dilating drops, dyes and anesthetics. When using any of these agents in diagnostic examinations, consider these important factors before, during, and after administration.

Dilating drops

Periodic comprehensive eye examinations are important for patients with ophthalmic diseases as well as patients undergoing routine examination in the absence of disease.¹ As part of comprehensive eye examinations (and other examinations), patients may require dilating drops.

Dilating drops, such as tropicamide, phenylephrine, and cyclopentolate, achieve dilation of the pupil via relaxation of the sphincter muscle of the iris and/or via the contraction of the dilator muscle of the iris. This step is necessary to perform examinations of structures located behind the iris, such as a fundoscopy.¹

Pupil dilation with any of these agents can typically last three hours and up to two days in some cases, although recovery within 24 hours is typical.^2-4 The resulting effect of pupil dilation causes patients to experience visual disturbances such as sensitivity to light and a decrease in visual acuity, which can render patients unfit for driving even hours after application.⁵ Therefore, it is vital to educate patients on the risks of driving in the immediate hours following pupil dilation.

Also, make patients aware that the use of sunglasses may not improve visual acuity due to glare. A study measuring the effect of glare on visual acuity demonstrated that sunglasses did not improve patients’ binocular visual acuity in the presence of glare.⁶ It is also important to counsel patients that they need to consider the time of day, light exposure while driving, and the familiarity of the roads when driving home.

One case report documented a patient with dilated pupils involved in a motor vehicle accident. The accident occurred due to the effects of bright lights while driving home after examination. The patient was liable for damages, and the motor vehicle insurance company denied coverage due to the patient driving while under the effects of a medication.⁷ The findings of this report highlight an important counseling point for patients who may decide to drive after pupil dilation.

Dyes

Agents such as dyes are commonly used to diagnose and examine corneal diseases or injuries. Dyes are compounds that induce color by chemically binding to ocular surface tissue, which allows for visualization of the bound tissue.⁸ Dyes are also available as combination ophthalmic solutions with anesthetic agents, providing staining action with the properties of an anesthetic agent. Commonly used dyes include fluorescein, rose bengal, indocyanine green, and combination agents such as fluorescein and benoxinate (an anesthetic).

Dyes have multiple applications in ophthalmology. They provide a visual for the clinician to efficiently identify and diagnose corneal abrasions, ulcerations, and herpetic lesions and help detect foreign bodies, dry eye, or a blocked tear duct, amongst other ocular surface alterations.⁹

Dyes can be administered intravenously through injection, but they are often used as topical drops and strips. Paper strips saturated with fluorescein are commonly used. They are applied to the eye by wetting the strip with one or two drops of sterile water, normal saline, or ocular irrigating solution and then touching the surface of the eye with the strip to produce an orange-yellow color stain on the eye.⁹ Upon impression of the fluorescein strip to the eye, the patient is asked to blink to spread the dye and coat the surface of the cornea. Any injuries will appear green upon presentation of a blue light during examination.

Anesthetics

Topical anesthetics play a vital role in providing comfort for patients during examinations that typically produce discomfort or pain. They produce a numbing effect by inhibiting nerve impulse to prevent the sensation of pain.⁹ Commonly used topical anesthetics in ophthalmology, such as tetracaine, proparacaine, and lidocaine, are very effective in providing comfort during examination and alleviating pain due to underlining ocular disorders.

The selection of anesthetic agent depends on its onset of action, duration of action, and individual patient needs. For example, proparacaine, a commonly used ocular anesthetic with short acting properties, is ideal for use in procedures such as tonometry and corneal scrapings.

Due to their potent ability to provide pain relief, it is important for staff to keep these agents in secure areas and out of reach of unsupervised patients. Some patients may try to take anesthetics for self-treatment of ocular pain, and these agents may lead to corneal abrasion and epithelial toxicity if abused.¹⁰ To prevent such self-harm, staff should not leave patients alone with unsecured access to these medications upon exiting exam rooms. Keep medications in locked areas such as cabinets, drawers, or closets to limit access to authorized staff members only. Also, institutional/clinic policies and procedures should address the prevention of patient access to medications in exam rooms.

Take-home points

Ophthalmic examinations often involve the use of one or more types of ocular medications. Patients with dilated pupils need proper patient counseling by staff on the effects of these drugs as well as the potential risks and liability incurred by driving. While agents such as dyes do not commonly produce long-term visual disturbances, explaining their effects to patients upon administration helps them to have a better understanding of what to expect. All medications, including ophthalmic anesthetics, should be kept away from unauthorized access and stored in a secure location.

As health-care professionals, our role in ensuring patient safety is paramount. Effective patient counseling and safe-guarding of medications can significantly reduce the risk of harm to patients. OP

REFERENCE:

1. American Academy of Ophthalmology Preferred Practice Patterns Committee. Comprehensive Adult Medical Eye Evaluation. Preferred Practice Pattern Guidelines. 20166
2. Tropicamide [package insert]. Lake Forest, IL: Akorn Inc; 2012.
3. Phenylephrine Hydrochloride Ophthalmic Solution, USP 2.5% [package insert]. Lake Forest, IL: Akorn Inc; 2011.
4. Cyclopentalate Hydrochloride Ophthalmic Solution, USP® [package insert]. Lake Forest, IL; Akorn Inc; 2006.
5. Montgomery DM, MacEwan CJ. Pupil Dilatation with Tropicamide. The Effects on Acuity, Accommodation and Refraction. Eye. 1989;3:845-848.
6. Jude EB, Ryan B, O’Leary BM, Gison JM, Dodson PM. Pupillary dilation and driving in diabetic patients. Diabetic Med. 1988;15:143-147.
7. Watts P, O’Duffy D, Riddell C, McLeod S, Watson SL. Can I drive after those drops, doctor? Eye. 1998;12:963-966.
8. Hoffer KJ, McFarland JE. Intracameral subcapsular fluor-escein staining for imporoved visualization during capsu-lorhexis in mature cataracts. J Cataract Refract Surg. 1993;19:566.
9. Bartlett JD, Bennett ES. Ophthalmic Drug Facts. 19th ed. St Louis, MO: Wolters Kluwer Health / Facts & Comparisons; 2008.
10. Rosenwasser GO. Complications of topical ocular anesthetics. Int Ophthalmol Clin. 1989 Fall;29:153-158.

Christian Arikape, PharmD, is a pharmacist at Bascom Palmer Eye Institute at the University of Miami in Miami, FL. Contact him at carikape@gmail.com.