Dry eye: A link with LASIK?

Manage meibomian gland dysfunction to avoid complications, surgeon says.

Before new warm device treatment.


After new warm device treatment.
Source: Scheffer Tseng, M.D.

Does post-LASIK dry-eye syndrome really exist? Scheffer C.G. Tseng, M.D., Ph.D., director, Ocular Surface Center, Miami, Fla., said surgeons need to consider meibomian gland dysfunction (MGD) as a risk factor before LASIK and continue to manage MGD during and after LASIK to avoid this complication.
“We cannot say that MGD is caused by LASIK, but we speculate that LASIK aggravates the pre-existing MGD,” said Dr. Tseng.
LASIK the most common refractive procedure used to correct myopia. But while LASIK has garnered high patient satisfaction, dry eye occurs in more than 50% of patients immediately after the procedure, said Dr. Tseng.
“It is generally believed that dry eye induced by LASIK is caused by corneal denervation generated after the creation of the flap or laser ablation, and is thought to be ‘transient,’ lasting for six months to one year, because normal cornea sensitivity and aqueous tear production recover between two weeks to six months after LASIK,” Dr. Tseng said. “However, reduced corneal sensation not only decreases the aqueous tear secretion, but also reduces the blink rate of which the latter lasts even one year after LASIK.”
Dr. Tseng and colleagues conducted a retrospective, year-long study of 17 patients (34 eyes), all but one of whom complained of persistent dry eye more than a year after receiving LASIK, but had been asymptomatic before their surgery.
The study revealed that the majority of these patients suffered from lipid tear deficiency (LTD) due to MGD, Dr. Tseng said.
“This evidence was presented using a method called kinetic tear interference images,” Dr. Tseng said.
Despite prior punctal occlusion, aqueous tear deficiency (ATD) was still confirmed by a fluorescein clearance tests in 16 eyes (47%), Dr. Tseng said. Even after ATD was corrected by additional punctal occlusion, the tear break-up time (TBUT) remained abnormally short (2.4 + 1.3 seconds) in all eyes, Dr. Tseng said.
“After Eyefeel (Kao, Inc., Japan) [a disposable eye-warming device] treatment, there was a significant improvement of Ocular Surface Disease Index and TBUT,” Dr. Tseng said. “Furthermore, kinetic tear interference image analyses showed there was a significant change of the tear interference pattern from a ‘vertical’ LTD pattern to a ‘horizontal’ normal pattern, and an improvement in the mean lipid spread time and lipid firm thickness.”
Dr. Tseng said he and his colleagues have thus concluded that dry eye following LASIK is not a transient complication.
“Its persistent and long-standing nature, although contributed in part by undercorrected ATD, is dominated by LTD,” he said. “This notion is supported by a significant improvement after eye-warming treatment. Therefore, dry eye induced by LASIK may result from disruption of the neuronal reflex linking the ocular surface not only to the lacrimal gland but also the meibomian gland and the blinking eyelid.”

Editors’ note: Dr. Tseng does not have any financial interest in his study. The study was conducted with a research grant from Kao, Inc., Japan, which also provided the Eyefeel disposable eye-warming device without cost.

Contact Information
Tseng: 305-274-1299, fax 305-274-1297, stseng@ocularsurface.com