CASE PRESENTATION
A 48-year-old white female presented for routine refractive surgery. Her preoperative refraction in the right eye was -3.50 +0.25 X 076 yielding 20/20 vision, and her refraction in the left eye was -2.75 sphere, yielding 20/20 vision. Preoperative pachymetry was 553 in the right eye and 558 in the left eye. Pupil size was measured at 4 mm in both eyes by Colvard pupillometry. Keratometry in the right eye was 46.50/45.37 @ 164, and in the left eye was 46.75/45.62 @ 6, with a normal pattern. The patient did not choose monovision and was scheduled for routine bilateral LASIK surgery.
We orally administered 5 mg of valium 30 minutes prior to surgery. To anesthetize the patient's eyes, I administered one drop of proparacaine before the sterile preparation, and a second drop before the keratectomy. I performed the procedure using a VISX S3 ActiveTrakTM laser and an AmadeusTM microkeratome.
I used an open-wire Lieberman speculum to hold the patient's lids open. However, because of her blepharospasm and tight orbits, I experienced difficulty in placing the suction.HOW WOULD YOU PROCEED?
1. What would be your next step?
2. What are other options when managing tight orbits?
3. At what point would you consider aborting LASIK and performing an alternative procedure such as PRK?
4. If possible, would you change or choose another microkeratome?
5. Which microkeratome would you prefer to use in a smaller orbit?
SURGICAL COURSE
One of the first steps I take when confronted with a tight orbit is to ensure that the patient is relaxed. I focus on controlling the tone of my voice (“vocal local”), and calmly describe what is happening. This not only calms the patient, but also alerts the staff to the tense situation at hand so they can focus on controlling a potentially difficult situation. In this case, the patient received preoperative valium, so despite her blepharospasm, she was very relaxed during the entire process. Next, I focus on the lid speculum. I ensure that it is maximally open, and gently and repeatedly apply the suction ring. If this is not feasible, I would consider removing the lid speculum. If a solid-blade speculum is used initially, switching to an open-wire speculum can be a helpful intermediate step before attempting to perform the procedure without a speculum.
After removing the suction ring, I reassess the patient's orbital anatomy, carefully distinguishing between narrow palpebral fissures and tight bony orbits. I also examine the depth of the orbit, which can also affect suction ring placement. If there is adequate bony orbital exposure, performing the keratectomy without a lid speculum may be effective. Depending on the microkeratome, protecting the lids with steri-strips or drapes may prevent lid margin damage during the keratectomy. The AmadeusTM unit has a protected space design that permits routine usage without a lid speculum, making it an attractive choice for managing tight orbits.
If the globe is deeply set within a tight bony orbit, the surgeon may need to consider more drastic measures, such as a lateral canthotomy or a retrobulbar injection of anesthesia to help proptosis and elevate the globe out of the orbit. In these extreme situations, I usually consider aborting the LASIK procedure and discussing an alternative procedure with the patient, depending on his or her refractive error. In a low myope, such as this patient, PRK would be an excellent option. In higher degrees of refractive error, a phakic intraocular lens or a lens extraction procedure may be necessary. In either case, aborting the current procedure, and discussing options with the patient is the best choice.
In this case, we removed the lid speculum. With adequate suction ring placement, we could perform the procedure carefully without a lid speculum in place. We used a sterile, dry 4 X 4 sponge to help retract the lids and better expose the globe. I also ensured that the lid margin was completely clear of the suction ring to prevent pseudosuction. The suction ring in a tight orbit can sometimes grab the lid margin, simulating adequate suction; however, in reality, pseudosuction results in a poor flap. For managing a smaller orbit, I would choose a microkeratome that could be used without a lid speculum. I would also choose one with a gearless system, as gears can jam on lashes and lids.
OUTCOME
On the first postoperative day, the patient had 20/25 uncorrected vision in both eyes. The refraction in each eye was -0.25 sphere. A slit lamp examination revealed temporal subconjunctival hemorrhaging in the right eye, but the cornea was otherwise clear with well-positioned flaps in both eyes. The patient had an uneventful postoperative course, and on her last postoperative visit, her refraction was -0.50 +0.50 X 086 in the right eye, yielding 20/20 vision. The refraction in the left eye was -0.25 +0.50 X 090, also yielding 20/20 vision. The subconjunctival hemorrhage resolved itself, and her corneas appeared clear with an excellent postoperative result after LASIK.
