CHAPTER 2
Patient Evaluation
A thorough preoperative patient evaluation is crucial for achieving a successful outcome after refractive surgery. It is during this encounter that the physician begins to develop an impression as to whether the patient is a good candidate for refractive surgery. Perhaps the most important goal of this evaluation is to identify who should not have refractive surgery.
Patient History
The evaluation actually begins before the physician sees the patient. Receptionists or refractive surgical coordinators who speak with a patient before the visit may get a sense of the patient’s goals and expectations for refractive surgery. If the patient is particularly quarrelsome about the time or date of the appointment or argues about cost, the surgeon should be informed. Such a patient may be too demanding to be a good candidate for surgery.
Important parts of the preoperative evaluation include an assessment of the patient’s expectations; his or her social, medical, and ocular history; manifest and cycloplegic refractions; a complete ophthalmic evaluation, including slit-lamp and fundus examinations; and ancillary testing (Table 2-1). If the patient is a good candidate for surgery, the appropriate refractive surgery procedures, benefits, and risks need to be discussed, and informed consent must be obtained.
Table 2-1
Because accurate testing results are crucial to the success of refractive surgery, the refractive surgeon must closely supervise office staff members who are performing the various tests (eg, corneal topography or pachymetry) in the preoperative evaluation. Likewise, the surgeon should make sure the instruments used in the evaluation are properly calibrated, as miscalibrated instruments can result in faulty data and poor surgical results.
Patient Expectations
One of the most important aspects of the entire evaluation is assessing the patient’s expectations. Inappropriate patient expectations are probably the leading cause of patient dissatisfaction after refractive surgery. The results may be exactly what the surgeon expected, but if those expectations were not conveyed adequately to the patient before surgery, the patient may be quite disappointed.
The surgeon should explore expectations relating to both the refractive result (eg, uncorrected distance visual acuity [UDVA; also called uncorrected visual acuity, UCVA]) and the emotional result (eg, improved self-esteem). Patients need to understand that they should not expect refractive surgery to improve their corrected distance visual acuity (CDVA; also called best-corrected visual acuity, BCVA). In addition, they need to realize refractive surgery will not prevent possible future ocular problems such as cataract, glaucoma, or retinal detachment. If the patient has obviously unrealistic hopes, such as a guarantee of 20/20 uncorrected visual acuity or perfect uncorrected reading and distance vision, even though he or she has presbyopia, the patient may need to be told that refractive surgery cannot currently fulfill his or her needs. The refractive surgeon should exclude patients with unrealistic expectations.
Social History
The social history and medical history can identify the vision requirements of the patient’s profession. Certain occupations require that best vision be at a specific distance. For example, a minister may desire that best uncorrected vision be at arm’s length, so that reading can be done at the pulpit without glasses. Military personnel, firefighters, or police may have restrictions on minimum UDVA and CDVA and on the type of refractive surgery allowed. Knowledge of a patient’s recreational activities may help guide the surgeon to the most appropriate refractive procedure or determine whether that patient is even a good candidate for refractive surgery. For example, a surface laser procedure may be preferable to a lamellar procedure for a patient who is active and at high risk of ocular trauma. Someone with highly myopic and presbyopic vision who is used to examining objects a few inches from the eyes without the use of glasses (eg, jeweler or stamp collector) may not be happy with postoperative emmetropia. Tobacco and alcohol use should be documented.
Medical History
The medical history should include systemic conditions, prior surgeries, and current and prior medications. Certain systemic conditions, such as connective tissue disorders and diabetes mellitus, can lead to poor healing after refractive surgery. In addition, potentially recurrent conditions such as herpes simplex virus infection should be recognized so that preventive measures can be instituted. An immunocompromised state—for example from cancer or HIV infection/AIDS—may increase the risk of infection after refractive surgery (see Chapter 10). Medications that affect healing or the ability to fight infection, such as systemic corticosteroids or chemotherapeutic drugs, should be specifically noted. The use of corticosteroids increases the risk of cataract development, which could compromise the long-term postoperative visual outcome. Use of certain medications—for example, isotretinoin and amiodarone—traditionally has been thought to increase the risk of poor results with photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) due to a potentially increased risk of poor corneal healing; however, there is no evidence for this association in the peerreviewed literature. Previous use of isotretinoin can damage the meibomian glands and predispose a patient to dry eye symptoms postoperatively. In addition, caution needs to be taken with patients using sumatriptan who are undergoing PRK or LASIK and with patients using hormone replacement
therapy or antihistamines who are undergoing PRK because of a possible increased risk of delayed epithelial healing.
Although laser manufacturers do not recommend excimer laser surgery for patients with cardiac pacemakers and implanted defibrillators, many such patients have undergone the surgery without problems. It may be best to check with the pacemaker and defibrillator manufacturer before laser surgery. Refractive surgery is also generally contraindicated in pregnant and breastfeeding women because of possible changes in refraction and corneal hydration status. Many surgeons recommend waiting at least 3 months after delivery and cessation of breastfeeding before performing the refractive surgery evaluation and procedure.
de Rojas Silva V, Rodríguez-Conde R, Cobo-Soriano R, Beltrán J, Llovet F, Baviera J. Laser in situ keratomileusis in patients with a history of ocular herpes. J Cataract Refract Surg. 2007;33(11):1855–1859.
Pertinent Ocular History
The ocular history should focus on previous and current eye problems such as dry eye symptoms, blepharitis, recurrent erosions, glaucoma, and retinal tears or detachments as well as on systemic conditions such as diabetes mellitus and connective tissue disorders. Ocular medications should be noted. A history of previous methods of optical correction, such as spectacles and contact lenses, should be taken. The stability of the current refraction is very important. Has the prescription for glasses or contact lenses changed substantially in the past few years? A significant change is generally thought to be greater than 0.50 D in either sphere or cylinder over the past year. A contact lens history should be taken. Important information includes the type of lenses used (eg, soft, rigid gas-permeable [RGP], polymethylmethacrylate [PMMA]); the wearing schedule (eg, daily-wear disposable, dailywear frequent replacement, overnight wear indicating number of nights worn in a row); the type of cleaning, disinfecting, and enzyming agents used; and how old the lenses are. Occasionally, a patient may have been happy with contact lens wear and needs only a change in lens material or wearing schedule to eliminate a recent onset of uncomfortable symptoms.
Because contact lens wear can change the shape of the cornea (corneal warpage), it is recommended that patients discontinue contact lens wear before the refractive surgery evaluation as well as before the surgery. The exact length of time the patient should be without contact lens wear has not been established. Current clinical practice typically involves discontinuing use of soft contact lenses for at least 3 days to 2 weeks (toric lenses may require longer) and of rigid contact lenses for at least 2–3 weeks. Some surgeons keep patients out of rigid contact lenses for 1 month for every decade of contact lens wear. Patients with irregular or unstable corneas should discontinue wearing their contact lenses for a longer period and then be re-refracted every few weeks until the refraction and corneal topography stabilize before being considered for refractive surgery. For patients who wear RGP contact lenses and find glasses a hardship, some surgeons suggest changing to soft contact lenses for a period to aid stabilization and regularization of the corneal curvature.
Patient Age, Presbyopia, and Monovision
The age of a patient is important in predicting postoperative patient satisfaction. The loss of near vision with aging should be discussed with all patients. Before age 40 years, individuals with emmetropic vision generally do not require reading adds to see a near target. After this age, patients need to understand that if their eyes are made emmetropic through refractive surgery, they will require reading glasses for near vision. They must also understand that “near vision” tasks include all tasks performed up close, such as applying makeup, shaving, or seeing the computer or cell phone