Some people experience dry eyes following surgery. Although it is usually temporary it can develop into dry eye syndrome. Underlying conditions with dry eye such as Sjögren's syndrome are considered contraindications to Lasik.
Treatments include artificial tears, prescription tears and punctal occlusion. Punctal occlusion is accomplished by placing a collagen plug in the tear duct, which normally drains fluid from the eye. Some patients complain of ongoing dry eye symptoms despite such treatments and dry eye symptoms may be permanent.
Dry eyes can usually be diagnosed by the symptoms alone. Tests can determine both the quantity and the quality of the tears. A slit lamp examination can be performed to diagnose dry eyes and to document any damage to the eye. A Schirmer's test can measure the amount of moisture bathing the eye. This test is useful for determining the severity of the condition. A five-minute Schirmer's test with and without anesthesia using a Whatman #41 filter paper 5 mm wide by 35 mm long is performed. For this test, wetting under 5 mm with or without anesthesia is considered diagnostic for dry eyes.
If the results for the Schirmer's test are abnormal, a Schirmer II test can be performed to measure reflex secretion. In this test, the nasal mucosa is irritated with a cotton-tipped applicator, after which tear production is measured with a Whatman #41 filter paper. For this test, wetting under 15 mm after five minutes is considered abnormal
Treatment
A variety of approaches can be taken to treatment. These can be summarised as: avoidance of exacerbating factors, tear stimulation and supplementation, increasing tear retention, and eyelid cleansing and treatment of eye inflammation.
Dry eyes can be exacerbated by smoky environments, dust and air conditioning and by our natural tendency to reduce our blink rate when concentrating. Purposefully blinking, especially during computer use and resting tired eyes are basic steps that can be taken to minimise discomfort. Rubbing one's eyes can irritate them further, so should be avoided. Conditions such as blepharitis can often co-exist and paying particular attention to cleaning the eyelids morning and night with mild shampoos and warm compresses can improve both conditions.
Pre-manufactured scleral lenses for dry eye patients can be fitted from a set of available lenses by using a trial and error process, which lasts over the course of days, weeks, or months. Newer technology now also allows highly precise custom fitted scleral lenses to be manufactured and milled from scratch after taking a non-invasive 3D digital image of a patient's eye using devices such as an Optical coherence tomography (OCT) scanner. Digital images can also be manipulated to incorporate vision correction and wavefront guided optics, allowing most dry eye patients to achieve some level of vision improvement, with some users achieving 20/15 or better vision. Previously clouding was a periodic complaint of scleral lens wearers, however this problem has been reduced by better fitting techniques and improved supplemental eye drop choices. Many GP and Scleral lenses are also treated with a Plasma Lens treatment prior to fitting in order to increase long term wettability and comfort. Lenses can be then be retreated periodically, such as on an annual basis.