Lacritin and Heparanase Levels in Human Tears After Laser Refractive Surgery

Lacritin is a naturally occurring tear protein with antimicrobial activity that is capable of
stimulating mitogenesis in human corneal epithelial cells and promoting production of tears
in lacrimal gland acinar cells. A recently developed immunoassay for lacritin may help
characterize the lacritin response following refractive surgery with the possible development
of recombinant lacritin as a novel therapeutic agent for wound healing. Heparanase (HPSE)
acts as a regulator for lacritin by cleaving heparan sulfate chains and allowing lacritin to
bind. We aim to measure both tear lacritin and HPSE pre- and post-operatively to elucidate
lacritin and HPSE's response in patients undergoing PRK (photorefractive keratectomy) and
LASIK (Laser-assisted in situ keratomileusis) at the Walter Reed Center for Refractive
Surgery.

Inclusion Criteria:

- Active duty US Army Soldiers eligible for care at FBCH

- Undergoing PRK or LASIK

- Male or female, of any race, and at least 21 years old and not older than 55 years old
at the time of the tear collection. The lower age limit of 21 years is intended to
ensure documentation of refractive stability.

- Appropriately aged individuals who report that their eyes are "normal" and who have no
active eye illness as determined by the principal investigator or sub-investigator.

- Ability and willingness to understand and provide informed consent to participate in
this study.

- Up to -10.00 diopters of myopia.

- Subject must expect to be located in the greater Washington DC area for a 12 month
period post-operatively.

- Consent of the subject's command (active duty) to participate in the study.

- Access to transportation to meet follow-up requirements.

Exclusion Criteria:

- Any reason to be excluded for PRK or LASIK

- Female subjects who are pregnant, breast-feeding or intend to become pregnant during
the study. Female subjects will be given a urine pregnancy test prior to participating
in the study to rule out pregnancy. [Pregnancy and breastfeeding are contraindications
to refractive surgery in general, including PRK, whether participating in this study
or not]

- Patients with known sensitivity or inappropriate responsiveness to any of the
medications used in the post-operative course.

- Any physical or mental impairment that would preclude participation in any of the
examinations.

- Anterior basement membrane dystrophy

- History of recurrent epithelial erosion

- Significant dry eye (symptomatic with Schirmer <5mm at 5 minutes)

- Other corneal epithelial disorder or healing abnormality

- Individuals with any infectious or inflammatory ocular conditions (e.g. have "pink
eye" or uveitis).

- Individuals diagnosed with dry eye or other ocular surface condition, including but
not restricted to neurotropic keratitis, anterior basement membrane dystrophy, and
recurrent corneal erosions.