The study purpose is to evaluate corneal sensitivity in patients that have Stage 1 Neurotrphic Keratopathy (NK). Identifying patients with Stage 1 NK, may predict those who will in the future require rhNGF for optimal visual performance.

The purpose of this study is to evaluate corneal sensitivity in a cross-section of patients with signs of dry eye disease (DED), correlating findings against clinical parameters relating to the severity of disease and impact on quality of vision. Identifying those patients with Stage 1 Neurotrophic Keratopathy (NK), i.e. those with corneal staining and reduced sensitivity, may predict those who will in the future require rhNGF for optimal visual performance.

Inclusion Criteria:

*Patients with the following: A diagnosis of dry eye disease Central or inferior corneal fluorescein staining defined by the Oxford Scale Reduced tear break up time (TBUT) ≤ 10 seconds.

• Able to comprehend and sign a statement of informed consent.
• Willing and able to complete all required postoperative visits.

Exclusion Criteria:

• Ocular surgery (e.g., intraocular, oculoplastic, corneal, or refractive surgical procedure) performed within the last 3 months or at any time in the investigator's clinical judgment if it would interfere with the outcome measures of this study.
• Evidence of BAK or other chemical toxicity that, in the best judgment of the investigator, is causing reduced corneal sensitivity
• Concomitant use of daily contact lenses that, in the best judgment of the investigator, is causing reduced corneal sensitivity
• Clinically significant ocular trauma.
• Active ocular Herpes simplex or Herpes Zoster infection
• Ocular inflammation (uveitis, iritis, scleritis, episcleritis, keratitis, conjunctivitis) at the discretion of the investigator.
• Ocular infection (e.g., viral, bacterial, mycobacterial, protozoan, or fungal infection or the cornea, conjunctiva, lacrimal gland, lacrimal sac or eyelids including hordeolum/stye).
• Active, systemic, or local disease condition that causes clinically significant ocular surface irritation such that it could interfere with the study findings.
• Moderate to severe (Grade 2-4) allergic, vernal or giant papillary conjunctivitis.
• Severe (Grade 3 or 4) inflammation of the eyelid (e.g., blepharochalasis, staphylococcal blepharitis or seborrheic blepharitis)
• Eyelid abnormalities that significantly affect the lid function (e.g., entropion, ectropion, tumor, edema, blepharospasm, lagophthalmos, severe trichiasis, severe ptosis).
• Ocular surface abnormality that may compromise the corneal integrity (e.g., prior chemical burn, recurrent corneal erosion, map dot fingerprint dystrophy, or the effect of any other ophthalmic medication that might in the opinion of the investigator compromise the ocular surface integrity).
• Participation in this trial in the same patient's fellow eye
• Patients who are under age 18, pregnant or breastfeeding, or who may become pregnant during participation in the study.