Preop evaluation, education crucial to dry eye management in refractive surgery patients

Issue: May 2004

ByJimmy Jackson, MS OD FAAO

Jimmy Jackson, MS, OD, FAAO [photo] Jimmy Jackson, MS, OD, FAAO, is president and director of clinical operations at InSight LASIK in Lafayette, Colo. He can be reached at 1120 W. South Boulder Rd., Suite 102, Lafayette, CO 80026; (303) 665-7577; fax: (303) 665-3633; e-mail: jimmy@insightlasik.com. Dr. Jackson has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.

Dry eye is the number one complication following LASIK, and it has been reported in up to 70% of patients during the immediate postoperative period. Dry eye can cause a plethora of problems including delayed healing, fluctuations in vision, discomfort and decreased vision. Photorefractive keratectomy and conductive keratoplasty patients are somewhat less prone to dry eye postoperatively than are LASIK patients, but they can present management challenges as well. This month’s column will discuss strategies for these three types of surgical patients.

Preop counseling and evaluation

I tell every refractive surgery candidate to expect to experience some level of dryness in the immediate postoperative period. In addition, I tell these patients that the dryness can last from a few days to a few months, rarely extends beyond 3 months and that there is the possibility of dry eye symptoms being made permanently worse. But I do say that I expect them to eventually return to their preoperative level of dryness.

I rank patient’s dry eye preoperatively on a 0-4 scale. Patients who score a 4 are not candidates for any refractive procedure. Patients who score a 3 are not candidates for LASIK, but will be considered for PRK or CK. Patients who score a 2 or below are considered candidates for all three procedures.

The preoperative dry eye evaluation should consist of the following:

thorough case history
review of medications and systemic conditions
slit-lamp exam of lids, lashes and adnexa
slit-lamp exam of cornea
grade the quality of the tear film
grade the lacrimal lake
use NaFl dye to check for staining and to measure tear film break-up time
measure tear production by some method — I prefer the Zone-Quick Phenol red string test (Menicon)

Rank Patients’ Dry Eye Preoperatively

0 No signs or symptoms of dry eye.
1 Mild signs of dry eye with no symptoms.
2 Mild to moderate signs plus mild symptoms of dry eye.
3 Moderate to significant signs plus symptoms alleviated by treatment.
4 Significant signs and symptoms not alleviated by treatment.

Any signs or symptoms of dry eye should be addressed preoperatively. You want a pristine cornea for surgery, and it is wise to alert the patient to the presence of any pre-existing dry eye.

Preoperative dry eye therapies can include the following:

artificial tears
punctal occlusion
treatment for marginal blepharitis
treatment for meibomian gland dysfunction
Restasis (cyclosporine, Allergan)

Surgical considerations with dry eye

LASIK is felt to cause increased dryness in the immediate postoperative period in a variety of ways. The disruption of the nerve complex caused by creation of the flap is considered the primary cause.

Recent research has generated debate regarding flap hinge position. A study by Dr. Eric Donnenfeld compared nasal-hinged flaps with superior-hinged flaps. This prospective, randomized trial included 52 patients who underwent bilateral LASIK. One eye received a nasal hinge while the fellow eye received a superior hinge. His conclusion was that both types of flaps created an increase in dry eye signs and symptoms, but that they were milder in the eye with the nasal hinge.

Other aspects of the role of the flap in causing dry eye currently being debated include the depth (thinner flaps may cause more dry eye) and the diameter of the flap (larger flaps may cause more dry eye). PRK also disrupts the superficial corneal nerves, but to a lesser degree than does LASIK. CK causes the least amount of dry eye because it involves no cutting of corneal nerves, nor any removal of corneal tissue. I still inform CK patients that they should also expect some dryness postoperatively secondary to epithelial disruption associated with the placement of the spots, plus some degree of dryness due to corneal steepening.

Hyperopic procedures in general are felt to cause more dryness problems than myopic procedures because, when the cornea is steepened, it is more difficult for it to retain adequate tear coverage.

Postop dry eye management

I recommend a staged approach to dry eye management. All patients are given nonpreserved artificial tears and are urged to use them at least hourly for the first 24 hours and at least every 2 hours for the next 48 to 72 hours. I recommend that patients use nonpreserved artificial tears for the first week, and then I allow them to switch to preserved artificial tears if they desire. Systane (Alcon) is my favorite preserved artificial tear.

Staged Treatment

Patient education
Non-preserved artificial tears
Punctal occlusion
Maintain hydration
1) Increase water content
2) Maintain adequate humidity: a humidifier in bedroom or a week in Hawaii
Oral supplementation
1) Generic flaxseed oil
2) Generic fish oils
3) HydroEyes (ScienceBased Health)
4) TheraTears Nutrition (Advanced Vision Research)
Restasis
Permanent punctal occlusion
1) External silicone — available from a variety of vendors, but I prefer the Parasol from Odyssey Medical
2) Internal silicone — Herrick Lacrimal Plug from Lacrimedics
3) Shape changing — SmartPlug from Medennium. This is a thermodynamic hydrophobic acrylic polymer that changes from a rigid, solid rod at room temperature to a custom-fitted soft gel plug at body temperature
Newer technologies
1) Panoptx — high-quality sun glasses with an orbital seal to create a moisture chamber effect
2) Nature’s Tears EyeMist (Bio-Logic Aqua Technologies) — a sterile, non-preserved, hypotonic, low-osmolarity, tissue-culture grade water that is applied as a mist to the face and eyes

Dry eye and the myriad of symptoms that go with the condition are explained (for example, most patients do not equate fluctuations in vision with dryness) to the patient, and he or she is urged to slowly taper the use of artificial tears depending upon symptoms.

For patients who demonstrate non-resolving dry eye signs or symptoms at the 1-week visit, I recommend punctal occlusion with long-lasting synthetic plugs. These synthetic plugs last 1 to 3 months vs. 3 to 7 days for collagen plugs and are just as easy to insert. They have become my punctal plugs of choice for refractive surgery patients. These synthetic plugs are available from Oasis (Soft Plug Absorbable, made of an absorbable copolymer of glycolic acid and trimethylene carbonate), Odyssey Medical (Extend, made of an absorbable copolymer of glycolic acid and trimethylene carbonate) and Surgical Specialties (UltraPlug Extended Wear, made from a synthetic absorbable suture material, E-caprolactonr-L-lactide copolymer-PCL). They come in a variety of sizes (0.3 and 0.4 are most commonly used for inferior puncta and 0.2 and 0.3 are most commonly used for superior puncta). Their cost is about $6/plug. I rarely use permanent punctal occlusion and reserve that for patients who require repeated occlusion with the long-lasting synthetic plugs.

For patients who require punctal occlusion, I also discuss ancillary therapy. That consists of recommending excellent hydration (drinking lots of water), educating them regarding maintaining good humidity in their environment (humidifier in the bedroom, being aware of activities that can induce dryness) and discussing and recommending oral nutritional supplementation containing omega 3 fatty acids, which are felt to improve meibomian gland function and the quality of the tear film. I have seen neither positive nor negative effects with Vitamin C, so I do not recommend it to patients.

For patients who remain symptomatic with this level of therapy, I suggest Restasis twice daily. Restasis’ mechanism of action is an immunosupressor and works best in dry eyes with an underlying inflammatory component. With Restasis, it is vitally important to alert patients of two downsides: it is expensive (will cost about $200/month if they use two vials/day, which is the recommendation found in the patient booklet), and it takes about 2 to 3 months to derive maximum therapeutic benefit, so they must be patient.

Finally, using a dry eye summary page in your chart will make it easier to keep up with what you have told the patient and with different treatment options you have tried. It gives you a place to readily review your treatment and the patient’s progress. It will save you time and also potential embarrassment by avoiding repeating yourself or by recommending a treatment that has already been unsuccessful.