Friday, December 7, 2012

Eyewear special in the Dry Eye Shop

Christmas Special!

This coupon gets you 15% off all eyewear purchases of $50 or more in the shop, from now till midnight on December 11th. If you have any trouble with the link, you can type "EyewearDec12" in the Enter Coupon place.

Enjoy! - For those who haven't been in the shop for awhile, I have a full selection of 7Eye and Wiley-X eyewear now with the removable foam-lined gaskets, in addition to the Tranquileyes Moisture Release glasses and a various low-cost favorites (Onion Goggles, Dustbusters) . You can also use the coupon to stock up on spare eyecups.

Lest anyone get confused - bear in mind eyewear means optical products (glasses/sunglasses), not night eye protection (Tranquileyes and such). But don't worry, I'll be running specials on night eye protection a bit later in the month too.


Abstract: Traditional Chinese medicine in dry eye

Dry eye is a common health problem worldwide, causing significant discomfort and inconvenience to sufferers. The conventional treatment of dry eye via topical administration of eye drops is deemed palliative and unsatisfactory to many. Traditional Chinese medicine (TCM) has shown some promise in dry eye treatment; however, the extent of its use and acceptance is uncertain. We evaluated the knowledge, attitude, and practice of institutional TCM practitioners in the treatment of dry eye in Singapore. A questionnaire was generated to address the study aims and sent to TCM practitioners listed in the Singapore TCM practitioners' board database. About three quarters of respondents thought that dry eye was not severe enough to be a public health burden but most thought that TCM was effective in the treatment of dry eye. Acupuncture and herbal medicine were most commonly used TCM modalities in dry eye treatment, and a single TCM treatment session would be charged S$20-50 by the practitioner. The majority of surveyed institutional TCM practitioners in Singapore believe that TCM is relevant in dry eye treatment. Public awareness should be raised regarding the availability of TCM as alternative medicine for dry eye.

ScientificWorldJournal. 2012;2012:923059. doi: 10.1100/2012/923059. Epub 2012 Nov 8.
Lan W, Lee SY, Lee MX, Tong L.
Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore 168751 ; Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.

Wednesday, December 5, 2012

Abstract: BAK, again, and, um, why?

I don't get it.

OK it looks like a well done study with important results.


There are approximately a gajillion published studies on the sins of BAK against the cornea and beyond, and we have to kill more bunnies to re-prove it how many more times? Quit using the durned stuff already. It's not like we don't have other effective preservatives. Oh - ever heard of preservative-free?

We investigated in a rabbit model, the eye distribution of topically instilled benzalkonium_(BAK) chloride a commonly used preservative in eye drops using mass spectrometry imaging. Three groups of three New Zealand rabbits each were used: a control one without instillation, one receiving 0.01%BAK twice a day for 5 months and one with 0.2%BAK one drop a day for 1 month. After sacrifice, eyes were embedded and frozen in tragacanth gum. Serial cryosections were alternately deposited on glass slides for histological (hematoxylin-eosin staining) and immunohistological controls (CD45, RLA-DR and vimentin for inflammatory cell infiltration as well as vimentin for Müller glial cell activation) and ITO or stainless steel plates for MSI experiments using Matrix-assisted laser desorption ionization time-of-flight. The MSI results were confirmed by a round-robin study on several adjacent sections conducted in two different laboratories using different sample preparation methods, mass spectrometers and data analysis softwares. BAK was shown to penetrate healthy eyes even after a short duration and was not only detected on the ocular surface structures, but also in deeper tissues, especially in sensitive areas involved in glaucoma pathophysiology, such as the trabecular meshwork and the optic nerve areas, as confirmed by images with histological stainings. CD45-, RLA-DR- and vimentin-positive cells increased in treated eyes. Vimentin was found only in the inner layer of retina in normal eyes and increased in all retinal layers in treated eyes, confirming an activation response to a cell stress. This ocular toxicological study confirms the presence of BAK preservative in ocular surface structures as well as in deeper structures involved in glaucoma disease. The inflammatory cell infiltration and Müller glial cell activation confirmed the deleterious effect of BAK. Although these results were obtained in animals, they highlight the importance of the safety-first principle for the treatment of glaucoma patients.

PLoS One. 2012;7(11):e50180. doi: 10.1371/journal.pone.0050180. Epub 2012 Nov 27.
Brignole-Baudouin F, Desbenoit N, Hamm G, Liang H, Both JP, Brunelle A, Fournier I, Guerineau V, Legouffe R, Stauber J, Touboul D, Wisztorski M, Salzet M, Laprevote O, Baudouin C.

Careful what you get in your eye...

Would I have noticed this if I weren't raising sheep? Hmmm

A 57-year-old abattoir worker was seen at a general practitioner after sheep bile splashed into his left eye. Flourescein examination revealed extensive ulceration involving at least two-thirds of the corneal surface. Copious irrigation with normal saline, application of chloramphenicol ointment and an eye patch resulted in excellent healing within 2 days with return to normal vision for the patient thereafter.

BMJ Case Rep. 2012 Dec 3;2012. pii: bcr2012007439. doi: 10.1136/bcr-2012-007439.
Okullo AT, Low T, Baker LL.
Blacktown-Mt Druitt Hospital, Sydney, New South Wales, Australia.

Tuesday, December 4, 2012

Abstract: Activities that aggravate dry eye disease

We all know it... just a matter of doing it... e.g.

1) Turn off the A/C and ceiling fans OR put on your MCs
2) Get off the computer
3) Consider audio books
4) Get off the computer
5) Put on your moisture chambers when you go outside
6) Get off the computer

Prolonged visually stressful activities aggravate dry eye disease (DED). The duration spent on such activities and their relationship with DED clinical features were investigated. Patients completed an activity log as they performed their usual activities over 1 typical rest day and 1 typical work day. The log included time spent in an air-conditioned environment, windy environment, driving, watching television, computer use, reading, watching a movie in the theatre, and wearing contact lens. Average daily activity hours were calculated and correlated with clinical features of DED. Thirty-five logs were returned. Positive correlation was found between watching television and episodic blurred vision (P < 0.01). Computer use was negatively correlated with episodic blur vision, burning sensation, and gritty sensation (P < 0.05). Negative correlation was found between time spent in windy environments, driving, reading, and certain DED symptoms (P < 0.05). Reading correlated positively with severity of corneal fluorescein staining and reduced Schirmer's values (P < 0.03). The use of air conditioning correlated negatively with episodic blur vision but positively with visual blurring that improves with lubricants (P = 0.02). This study is the first to evaluate the relationship between time spent on DED-aggravating activities and DED clinical features. Negative correlations between certain activities and DED symptoms suggest an unconscious modification of lifestyle to alleviate symptoms.

ScientificWorldJournal. 2012;2012:589875. doi: 10.1100/2012/589875. Epub 2012 Oct 24.
Iyer JV, Lee SY, Tong L.
Ocular Surface Research group, Singapore Eye Research Institute, Singapore 168751 ; Corneal and External Eye Services, Singapore National Eye Centre, Singapore 168751.

Abstract: Lid hygiene and so on


I appreciate that we don’t want to go overboard pushing more consumer products, BUT, can’t we at least ditch the bleeping baby shampoo already? Why would we want soap of any kind in our eyes when our tear film is so unstable anyway?

Disorders of the lacrimal functional unit are common in ophthalmological practice, with meibomian gland dysfunction, blepharitis, and dry eye forming a significant part of the general ophthalmologist's practice. The eyelid and its associated structures form a complex organ designed to protect the fragile corneal surface and improve visual acuity. This organ is subject to a number of disorders, including meibomian gland dysfunction, dry eye syndrome, anterior blepharitis, allergic and dermatological conditions, and disorders associated with contact lens use. Although commonly described separately, disorders of the lacrimal function unit are better considered as a group of interacting pathologies that have inflammatory mediators as a central feature. Eyelid hygiene, in the sense of routine cleansing and massage of the eyelids, is well accepted in the management of many disorders of the eyelid. However, a broader concept of eyelid health may be appropriate, in which eyelid cleansing is but a part of a more complete program of care that includes screening and risk assessment, patient education, and coaching. The ophthalmologist has an important role to play in helping patients persist with routine eyelid care that may be long-term or lifelong. A number of preparations exist to make routine eyelid care both more effective and more pleasant, and might also improve compliance. Several such preparations have been devised, and are being assessed in clinical studies, and appear to be effective and preferred by patients over traditional soap and water or baby shampoo.

Clin Ophthalmol. 2012;6:1689-98. doi: 10.2147/OPTH.S33133. Epub 2012 Oct 25.
Benitez-Del-Castillo JM.
Ocular Surface and Inflammation, Department Ophthalmology, Hospital Clinico San Carlos, Madrid, Spain.


I like wordplay and all that, but, er, this is kind of getting ridiculous.

Abstract: Oral contraceptives, contact lenses and dry eye

PURPOSE:: The aim of this study was to examine the relationship among oral contraceptive pill (OCP) use, contact lens wear, and dry eye signs and symptoms in healthy young women.
 METHODS:: Fifty-two women using OCPs and 45 women not using any form of hormonal contraception were enrolled. Medical, menstrual, and contact lens histories were obtained and dry eye symptoms assessed using the Ocular Surface Disease Index (OSDI) and Symptom Assessment iN Dry Eye (SANDE) questionnaires. Tear osmolarity testing was performed using the TearLab Osmolarity System.
 RESULTS:: The mean age of all subjects was 26.0 ± 3.7 years. There were no significant differences in any of the measurements between the follicular and luteal phases. Although SANDE scores were significantly higher in subjects with OCP and recent contact lens use (P < 0.01), there were no significant differences in OSDI and tear osmolarity among the same subject groups. Subjects who reported both OCP and recent contact lens use had significantly higher OSDI and SANDE scores (P = 0.015 and P < 0.001, respectively).
 CONCLUSIONS:: There were no differences between the phases of the menstrual cycle. Tear osmolarity was not affected by OCP or contact lens use in young women. However, the combination of OCP use and contact lens wear may increase the severity of dry eye symptoms.

Cornea. 2012 Oct 18. [Epub ahead of print]
Chen SP, Massaro-Giordano G, Pistilli M, Schreiber CA, Bunya VY.
Departments of *Ophthalmology †Obstetrics and Gynecology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

Abstract: Tear film osmolarity in patients taking IOP lowering meds

To evaluate tear film osmolarity in patients treated with intraocular pressure-lowering medications.
Forty patients treated for glaucoma or ocular hypertension (OHT) were consecutively recruited for the study. Each patient was asked to complete an evaluation of ocular surface disease symptoms, the Ocular Surface Disease Index, and underwent a complete evaluation of the ocular surface including measurement of tear film osmolarity, Schirmer test, tear breakup time (TBUT), and corneal and conjunctival staining.
Twenty-four patients (60%) reported ocular surface disease symptoms. Nineteen patients (47.5%) had a tear osmolarity ≤308 mOsms/L, 11 (27.5%) between 309 and 328 mOsms/L, and 10 (25%) >328 mOsms/L. A tear deficiency was observed in 20 patients (50%). Twenty-seven patients (67.5%) had an abnormal tear quality analyzed with TBUT, and 16 patients (40%) showed positive staining using the Oxford schema. Tear osmolarity was significantly correlated to Ocular Surface Disease Index (r = 0.486; P = 0.002) and TBUT (r = -0.49; P = 0.009). There was a statistically significant correlation between tear osmolarity and the number of drugs (r = 0.409; P = 0.009), the number of instillations (r = 0.405; P = 0.01), and the number of instillations of preserved eye drops (r = 0.629; P < 0.0001). Using the multiple regression method, tear osmolarity remained significantly correlated to the number of instillations of preserved eye drops (P = 0.004).
Tear osmolarity was increased in patients treated for glaucoma or OHT, particularly in those using multiple preserved eye drops. The evaluation of the ocular surface of patients treated for glaucoma or OHT may benefit from such analysis, and future trials for new intraocular pressure-lowering eye drops should thus evaluate tear osmolarity.

Cornea. 2012 Sep;31(9):994-9. doi: 10.1097/ICO.0b013e31823f8cb6.
Labbé A, Terry O, Brasnu E, Van Went C, Baudouin C.
Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, Paris, France.

Abstract: Sclerals instead of tarsorrhaphy

This is one of those studies where just reading the title makes me go "Ahhhh" as I feel muscles relaxing:

...especially since I've been noticing this year, to my horror, that tarsorrhaphy seems to be coming back into vogue. My emphases below:
PURPOSE:: Most ophthalmologists are unaware of the therapeutic applications of gas-permeable scleral contact lenses for the prevention and treatment of ocular complications in patients with facial nerve palsy and concomitant neuroparalysis.

METHODS:: The case reports refer to 3 patients who developed unilateral lagophthalmos and corneal anesthesia after an acoustic neuroma or intracranial tumor resection. Two patients explicitly requested a tarsorrhaphy to be opened because they were incapacitated by the limited visual acuity and visual field. Tarsorrhaphy was not an acceptable aesthetic solution for the third patient. Fluid-ventilated scleral lenses were fitted because they protect the cornea by creating a precorneal fluid reservoir while optimizing visual acuity.
 RESULTS:: The follow-up periods were 3, 17, and 18 years. Two patients wear the contact lenses full time, but the wearing time is limited to 10 hours per day for the third patient. All patients were instructed not to wear their lenses while sleeping. Two eyes required a corneal transplant, but lens wear could be resumed 4 to 6 weeks after transplantation. The learning curve for the insertion and removal of this large-diameter lens is the main obstacle for a patient, especially when there is loss of corneal sensation. 
CONCLUSION:: Scleral lens wear is a valid long-term alternative to standard treatment options such as tarsorrhaphy for patients with corneal exposure and corneal anesthesia as a consequence of postsurgery facial nerve paralysis. Scleral contact lenses provide these patients with effective protection of the ocular surface in an aesthetically acceptable way while optimizing visual function.
 Good show.

Cornea. 2012 Oct 15. [Epub ahead of print]
Weyns M, Koppen C, Tassignon MJ.
*Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium †Faculty of Medicine and Health Sciences, University of Antwerp, Wilrijk, Belgium.

Abstract: Review of 892 blepharoplasties

Wow - lot of data went into this one.

Here's a simple takehome message for people considering blepharoplasty (eyelid surgery):

CONCLUSIONS Dry eye symptoms and chemosis are common following blepharoplasty...

So why do I get calls from so many blepharoplasty patients who say they had no idea this could happen? Is it the classic LASIK type "informed consent" breakdown, where the significance of the information escapes them because it's played down? Are they literally never told because the doctors performing the surgeries are oculoplastic docs who don't talk to their cornea colleagues enough or - worse - cosmetic surgeons who don't know or care about corneas in general?

Anyway, going back to the beginning... The study in question is a 10-year review of a whole bunch of eyelid surgery cases. Of those they were able to include in the study, about a quarter had dry eye and chemosis. There were also some specific risk factors that are worth reading about.

To determine the incidence of and risk factors associated with dry eye symptoms (DES) and chemosis following upper or lower blepharoplasty. To examine the outcomes among long-term blepharoplasty data to better understand the incidence of and risk factors associated with dry eye symptoms (DES) and chemosis, to evaluate the known risk factors for DES in the general population, and to analyze intraoperative procedures (such as forehead-lift, midface-lift, canthopexy, and canthoplasty) to determine their effects on DES and chemosis.
A retrospective medical record review was performed among all the cases of upper or lower blepharoplasty performed by the senior author during a 10-year period (January 1999 through December 2009). A self-reported dry eye questionnaire was used to collect baseline and follow-up data. Patients with incomplete medical records, multiple (>1) revision procedures, less than 3 weeks of postoperative follow-up data, or a history of Sjögren syndrome, severe thyroid eye disease, histoplasmosis ocular infection, periocular trauma causing eyelid malposition, or radiotherapy for nasopharyngeal cancer were excluded from the study. Binary logistic regression analyses were performed to analyze the relationship between 13 preoperative and anatomical variables and DES or chemosis. χ2 Tests were performed to analyze the relationship between intraoperative risk factors and DES or chemosis.
In total, 892 cases met the study inclusion criteria. Dry eye symptoms and chemosis following blepharoplasty were reported in 26.5% and 26.3% of patients, respectively. The incidences of DES and chemosis were significantly higher in patients who underwent concurrent upper and lower blepharoplasty (P < .001) and in patients who underwent skin-muscle flap blepharoplasty (P = .001). Hormone therapy use and preoperative scleral show were associated with DES after blepharoplasty (P < .05). Male sex, preoperative eyelid laxity, and preoperative DES were associated with an increased incidence of chemosis following blepharoplasty (P < .05). Intraoperative canthopexy significantly increased the risk for developing chemosis (P = .009), and postoperative lagophthalmos significantly increased the risk for DES following blepharoplasty (P < .001).
Dry eye symptoms and chemosis are common following blepharoplasty, and the risk for developing these conditions may increase with intraoperative canthopexy, postoperative temporary lagophthalmos, concurrent upper and lower blepharoplasty, and transcutaneous approaches violating the orbicularis oculi muscle. Patients with a preoperative history of DES, eyelid laxity, scleral show, or hormone therapy use may be at greater risk for developing dry eyes or chemosis following surgery.

Arch Facial Plast Surg. 2012 Oct 15:1-8. doi: 10.1001/archfacial.2013.1. [Epub ahead of print]
Prischmann J, Sufyan A, Ting JY, Ruffin C, Perkins SW.

Abstract: The antiaging approach for the treatment of dry eye

The antiaging approach for the treatment of dry eye.

Dry eye is one of the most common eye disorders affecting millions of people. It causes ocular irritation or discomfort, and decreases functional vision, causing a dramatic deterioration in the quality of life. Although new treatments such as the P2Y2 agonist or cyclosporine eye drops have been developed and a certain level of patient satisfaction can now be obtained, no fundamental treatment has been developed. Currently, there is no therapy available to recover lacrimal function to its normal status. Recent progress in the understanding of aging has laid the foundations for a new way of thinking about intervention of the aging process. Because dry eye is accelerated by aging, a useful approach for the prevention or treatment of dry eye may be to interfere with the aging process. In the scientific community, there is a global consensus that calorie restriction can extend the life span of various kinds of animals, establishing an intervention to aging. Another important hypothesis believed to be involved in aging is the free radical theory. According to these theories, the aging process may be managed by controlling levels of calories or reactive oxygen species. In this review, these 2 important aging theories, calorie restriction and free radical aging, are examined, and we discuss how to apply these theories to the prevention and treatment of dry eye.

Cornea. 2012 Nov;31 Suppl 1:S3-8. doi: 10.1097/ICO.0b013e31826a05a8.
Tsubota K, Kawashima M, Inaba T, Dogru M, Matsumoto Y, Ishida R, Kaido M, Kojima T, Uchino M, Uchino Y, Ogawa Y, Nakamura S, Higuchi A, Shinmura K, Watanabe M, Kawakita T.

Abstract: Corneal epithelial toxicity of glaucoma meds

By using a biologically relevant and sensitive three-dimensional model of human corneal epithelium and multiple endpoint analysis, assessment of the potential for eye irritation and long-term compatibility of four registered ophthalmological preparations, ie, Timolabak(®), Timoptol(®), Nyogel(®), and Timogel(®), was performed. This approach enables classification of the potential for irritation, discriminating between mildly irritant and non-irritant ocular substances.
The exposure protocol included two time periods, ie, 24 hours (acute application) and 72 hours (repeated applications twice daily). This approach allows assessment of not only the acute reaction but also possible recovery, as well as mimicking the potential cumulative effects associated with long-term application. Using benzalkonium chloride (BAK) 0.01% as a positive control, the following parameters were quantified: cellular viability by MTT test, histological analysis by hematoxylin and eosin staining, passive release of interleukin-1α by enzyme-linked immunosorbent assay, and OCLN gene expression by quantitative real-time polymerase chain reaction.
Cell viability was reduced to under the 50% cutoff value after acute exposure (24 hours) to BAK 0.01%, and after repeated application (72 hours) of Timoptol and Nyogel. Histological analysis after acute exposure showed signs of superficial damage with all formulations, and severe changes after repeated applications of Timoptol, BAK 0.01%, and Nyogel. Timolabak and Timogel did not significantly alter the morphology of the human corneal epithelial cells after the different exposure times. Interleukin-1α release was greater than that for the negative control (>20 pg/mL) and the positive control (BAK 0.01%), Nyogel, and Timoptol treatments and not different after treatment with Timolabak and Timogel. Expression of OCLN, a sign of epithelial barrier impairment, was only significantly upregulated at 24 hours by BAK 0.01%, suggesting a toxic reaction at the ocular surface. OCLN was also overexpressed after repeated application of Nyogel and Timogel.

Clin Ophthalmol. 2012;6:1433-40. doi: 10.2147/OPTH.S35057. Epub 2012 Sep 5.
Meloni M, Cattaneo G, De Servi B.
VitroScreen In Vitro Research Laboratories, Milan, Italy.

Abstract: Role of medications in causing dry eye

Interesting piece - click on the title for full text of the study. As the authors state it's not an adequate discussion but at least underscores some important points.

 The role of medications in causing or aggravating DED is complex and this paper suffers from oversimplification and incomplete data. Nonetheless, sufficient information is available to make the following recommendations to clinicians.
 (1) The role of systemic and topical ocular medications in causing dry eye is probably underappreciated. There is a need to determine if the drying effects of systemic and topical ocular medications are additive or synergistic.
(2) Oral polypharmacy needs to be studied as a cause of dry eye. The total number of drugs should include not only prescription drugs, but topical ocular medications, over-the-counter medications, and herbals as well.
(3) Clinicians should remember that if a medication causes a dry mouth, it may also cause or aggravate dry eye.
(4) It is probable that the duration of topical ocular therapy is relevant as a cause of dry eye. Topical BAK may be the primary factor in causing DED and ocular surface disease in a given patient.
(5) It is important to question the diagnosis of primary Sjögren’s Syndrome without adequate laboratory confirmation if the patient has a history of polypharmacy or if onset of dry eye or mouth occurred within 3 months of a change in medication.
(6) Available on the National Registry of Drug-Induced Ocular Side Effects website,, are
     (a) bibliography of a drug’s side effect profile listed in Tables 3 and 4;
     (b) list of drugs causing dry mouth;
     (c) causes of polypharmacy.

Journal of Ophthalmology Volume 2012 (2012), Article ID 285851, 8 pages
Frederick T. Fraunfelder, James J. Sciubba, and William D. Mathers

Abstract: Using PROSE for lagophthalmos and exposure keratitis

Prosthetic replacement of the ocular surface ecosystem is a treatment developed by the Boston Foundation for Sight that uses a Food and Drug Administration-approved prosthetic device for the treatment of severe ocular surface disease to improve vision and discomfort in addition to supporting the ocular surface. Facial nerve paralysis has multiple causes including trauma, surgery, tumor, stroke, and congenital lagophthalmos. Subsequent lagophthalmos leading to exposure keratitis has been treated with copious lubrication, tarsorrhapy, eyelid weights, chemodenervation to yield protective ptosis, and palpebral spring insertion. Each of these treatments, however, has limitations and potential complications. The prosthetic replacement of the ocular surface ecosystem device provides a liquid bandage to protect the cornea from eyelid interaction and dessication in addition to improving vision. This report describes 4 patients with exposure keratitis who were successfully treated with prosthetic replacement of the ocular surface ecosystem devices at 2 clinical sites.

Ophthal Plast Reconstr Surg. 2012 Oct 3. [Epub ahead of print]
Gire A, Kwok A, Marx DP.
*Alkek Eye Center, Baylor College of Medicine, Houston, Texas; and †Boston Foundation for Sight, Needham, Massachusetts, U.S.A.

Abstract: Effect of low humidity on the tear film

PURPOSE:: To investigate the effect of exposure to a low relative humidity (RH) environment on tear film physiology.
 METHOD:: A controlled environment chamber was used to create 2 different environmental conditions. Ambient temperature was constant in both conditions (21°C) while the RH was set at 40% at the normal condition and at 5% in the desiccating environment. Tear evaporation, noninvasive tear break-up time, lipid layer thickness (LLT), osmolarity, ocular comfort, tear production, and ocular surface temperature were assessed in normal humidity and over a period of 60 minutes in the dry environment.
 RESULTS:: There was significant change in tear evaporation rate (P = 0.00), noninvasive tear break-up time (P = 0.00), LLT (P = 0.00), ocular comfort (P = 0.00), and tear production (P = 0.01) after exposure to the desiccating environment. No significant differences were observed between normal and dry environmental conditions in tear osmolarity (P = 0.09) and ocular surface temperature (P = 0.20).
 CONCLUSIONS:: Evaporation rate, tear LLT, ocular comfort, tear stability, and production were adversely affected by low RH. The tear film parameters observed after exposure to a desiccating environment for 1 hour were similar to those of the dry eye patient. Therefore, to avoid tear film disruption and possible ocular surface damage, the environmental conditions of dry locations need to be improved or the tear film should be protected against adverse environmental conditions.
Cornea. 2012 Sep 27. [Epub ahead of print]
Department of Vision Sciences, Glasgow Caledonian University, Glasgow, United Kingdom.