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Due to contact lens intolerance, dry eye is a major reason for patients to consider LASIK. Dry eye is also a common post-LASIK complication, with compromised tear function and ocular surface typically lasting for at least one-month after surgery. Recovery time after surgery is also increased when dry eye develops. These factors led a group of researchers to investigate whether preoperative dry eye affects the visual outcome and incidence of complications after LASIK, and whether it is a risk factor for severe dry eye after surgery.

Methods:

The investigators divided 543 eyes (290 patients) into three groups: those without dry eye (NDE), those with probable dry eye (PDE), and subjects with definite dry eye (DE). Subjects were diagnosed for DE or PDE and categorized into one of the three groups according to the modified criteria of the Japanese Dry Eye Association, which included the Schirmer test with anesthesia, tear Break-Up Time (BUT), fluorescein and rose bengal staining of the ocular surface, and symptom assessment. Follow-up tests were performed at 3, 6, and 12 months after the procedure. To evaluate the effectiveness of LASIK correction, uncorrected (UCVA), best-corrected visual acuity (BCVA), and manifest refraction in the spherical equivalent were examined at 1, 3, 6, and 12 months.

Results:

No significant differences were found among the groups in UCVA and BCVA, except at 1 month, when UCVA was better in the NDE than in the DE group (p>.03). In the DE group, manifest refractive deviation was slightly larger than in the NDE group only at 3 months (p>.01).

The mean results of the Schirmer test were lower in both the DE and PDE subjects compared with the NDE group at all follow-ups after LASIK. Tear BUT was shorter in the DE compared to the NDE group before and at post-LASIK follow-ups. For ocular surface abnormality, fluorescein scores were higher in the DE than the NDE group before and after LASIK up through the one-year mark. Similar results were found with the rose bengal scores.

Dryness was significantly more severe for the DE group compared to the NDE group before LASIK and at 3, 6, and 12 months. This also held true for the PDE vs. the NDE patients at 6 months and 1 year (See figure 1).

Conclusions:

The results indicate that the safety and efficacy of LASIK are not affected by preexisting dry eye status. However, preoperative dry eye is a risk factor for severe postoperative dry eye with lower tear function, more vital staining of the ocular surface, and more severe symptoms. Bottom line: those that start out with dry eye suffer more discomfort over a longer period. This is a significant problem, as more than 75% of the patients who undergo LASIK at their clinic have dry eye at the outset according to these investigators.

HydroEye^® is a patented, oral nutritional formulation for dry eye relief. More than 2000 doctors recommend it to their dry eye patients, and many report that it helps reduce dry eye symptoms in their LASIK patients. HydroEye has been reported to increase lactoferrin levels (an indicator of ocular surface health) by a mean of 40% in pre-LASIK patients.

References

1. Toda I, et al. Laser-assisted in situ keratomileusis for patients with dry eye. Arch Ophthalmol 120:1024-28, 2002.
2. Aras G, et al. Decreased tear secretion after laser in situ keratomileusis for high myopia. J Refract Surg. 16:362-4, 2000.
3. Toda I, et al. Dry eye after laser in situ keratomileusis. Am J Ophthalmol 132:1-7, 2001.

Figure 1 appears courtesy of Archives of Opthalmology, originally appearing in reference #1, above.