Reflex Tearing Research Articles

Basal and Reflex Human Tear Analysis: II. Chemical Analysis: Lactoferrin and Lysozyme

Unstimulated basal tears and stimulated tears were collected from normal controls, keratoconjunctivitis sicca (KCS) patients, and contact lens (CL) wearers. Basal tear volume (Periopaper®) and reflex tear volume (Schirmer Strip®) were measured and tears eluted from their respective strip with a TMED-acetic acid buffer. Lactoferrin and lysozyme concentrations were measured in the eluates. Concentration of lysozyme in basal tears was: 65 ± 43 mg% in normals; 44 ± 26 mg% in KCS, and 81 ± 50 mg% in CL wearers. Concentration of lysozyme in reflex tears was: 160 ± 73 mg% in normals, 74 ± 41 mg% in KCS, and 186 ± 83 mg% in CL wearers. Concentration of lactoferrin in basal tears was 137 ± 102 mg% in normals, 154 ± 82 mg% in KCS, and 157 ± 80 mg% in CL wearers. Concentrations of lactoferrin in reflex tears was: 327 ± 187 mg% in normals; 171 ± 69 mg% in KCS, and 302 ± 160 mg% in CL wearers. The lactoferrin concentration in all tear samples was consistently higher (1.6–3.5 times) than lysozyme. In basal tears, lactoferrin concentrations were not significantly different in the three groups. In reflex tears, however, lactoferrin was significantly lower in KCS than normal or CL wearers. The concentration of lysozyme in both basal and reflex tears was significantly lower in the KCS when compared to normal or CL wearers. Lysozyme and lactoferrin concentrations in both basal and reflex tears were similar in CL wearers and normal controls. The sampling and elution of basal and reflex tears as described appears to be a feasible technique for analysis of lysozyme-and lactoferrin concentrations by the electroimmunodiffusion technique and has potential diagnostic value.

Basal and Reflex Human Tear Analysis: I. Physical Measurements: Osmolarity, Basal Volumes, and Reflex Flow Rate

Minimally stimulated, retained “basal” tears and stimulated reflex tears were collected from normal controls, keratoconjunctivitis sicca (KCS) patients, and contact lens (CL) wearers. Basal tear samples were collected on small filter paper strips (Periopaper®) over a five-second period, and volume was measured by means of an electronic device (Periotron®). Collected basal tear volumes for KCS patients (0.84 ± 0.42 μl) were significantly lower (P <; 0.01) than normal controls (1.18 ± 0.36) and CL wearers (1.24 ± 0.27). Reflex tear flow rates were measured over a five-minute period on Schirmer strips. Volume was calculated by comparison of wet length with known volumes of 1% egg white lysozyme solution. The reflex tear flow rates in KCS patients (3.29 ± 3.57 μl/minute) were significantly lower than normal controls (5.71 ± 5.86) and CL wearers (6.96 ± 6.07). The elevation in CL wearers was not statistically significant when compared to normals. KCS patients are deficient in both basal and reflex tears compared to normals but have a more significant deficiency of basal tears. Female normals and CL wearers over 40 years of age have a higher tear osmolarity than those under 41 years of age. Female KCS patients over 40 years of age have a tear osmolarity that is not significantly different from female KCS patients under 41 years of age.

Basic Tear Flow: Does It Exist?

Tear flow and volume were measured in 15 normal volunteers, divided into young and old age groups, using subjective fluorophotometric analysis and Schirmer testing with and without topical anesthesia. Proparacaine 0.5% was found to anesthetize cornea and conjunctiva better than cocaine 4% and produced fewer complications. Older subjects responded to stimulation with less reflex tearing than younger subjects, but had an identical rate of physiologic tear flow, and equivalent corneal and conjunctival sensitivity. Tear flow and volume decreased significantly below physiologic values in both age groups following topical anesthetic instillation. Lid margin and cilia stimulation increased the tear turnover rate more than 300% despite adequate topical anesthesia. Flow rates determined by Schirmer testing with topical anesthesia were higher than both physiologic tear flow and tear flow following topical anesthesia when these values were determined by fluorophotometry. As sensory input was decreased, tear secretion fell correspondingly, implying that all significant tear flow results from reflex secretion.

Quantifying Adaptation to Contact Lenses: Two Case Histories

In the course of previous investigations, chloride concentration has been shown to be an eetive indicator of both hypotonic (reflex tear) and hypertonic (aberrant blink) tear shifts with contact lens presence. Described here are case histories which illustrate two diagnostic applications of this technique.

Artificial Eyes and Tear Measurements

Ninety-four consecutive persons with unilateral enucleations or eviscerations were tested by the Schirmer I and Schirmer II tests for tear production. The findings on the artificial eye were compared with those on the companion, living (control) eye. The collected data were subjected to statistical analysis. The control eyes were shown to respond in the normal manner, more tears without topical anesthetic than with it. The sockets of artificial eyes produced no more tears without anesthetic than with it. The control eyes produced a normal amount of reflex tears, whereas the sockets of many artificial eyes produced practically no reflex tears. Tear production in persons with no complaints was compared to those with noteworthy problems. Persons with problems had only half as much basic tear secretion as those without problems. Elimination of the stimulus to reflex tear production by removal of the cornea and by the presence of the prosthesis is suggested as the cause of dryness of the eye socket. The potential value of aqueous or oily artificial lubricants is mentioned.

Tear chloride as an adaptive index.

Tear chloride concentration was used as an indicator of hypotonic (reflex tear) response to contact lens presence in the eye. Individual responses to rigid and to hydrophilic lenses were thus monitored and quantitatively compared from the time of dispensing until full wearing time was achieved. Although the initial tear imbalances to hydrophilic lenses were somewhat less than those to rigid lenses, they were, nevertheless, detectable. Restoration to prefitting baseline levels was for the most part achieved within the first 5 days, and did generally parallel the reduction in subjective awareness experienced by the patient.

Osmolarity of tear microvolumes in keratoconjunctivitis sicca.

Determinations of tear film osmolarity were performed to evaluate their usefulness in diagnosing keratoconjunctivitis sicca (KCS) and to evaluate the possible role of elevated tear osmolarity in this disorder's pathogenesis. Tear samples were obtained using a new technique that virtually eliminates the problems of reflex tearing and sample evaporation. The tear osmolarity of 36 samples obtained from 31 normals eyes averaged 302 +/- 6.3 (SD) mOsm/liter; 38 samples obtained from 30 KCS eyes averaged 343 +/- 32.3 (SD) mOsm/liter. The sensitivity of a single measurement was 94.7% and the specificity was 93.7%. Tear samples taken on separate occasions from one normal subject ranged between 295 and 309 mOsm/liter; those obtained from a KCS patient ranged between 312 and 424 mOsm/liter. Hypersmolarity of the tear film in KCS may play an important role in inducing the disease seen in the cornea and conjunctiva.

Decreased Lacrimation and Amyotrophic Lateral Sclerosis

To the Editor.— I have read with interest Dr. Reuben Copperman's presentation (230:536, 1974) of the proposed relationship of decreased lacrimation and amyotrophic lateral sclerosis (ALS). Several points should be established. The Schirmer test is not necessarily a crude test if performed accurately and correctly with proper interpretation. Classically, lacrimation consists of tear production by two methods; reflex tearing from the lacrimal gland and, more important, basal secretion through the accessory lacrimal glands of Krause and Wolfring located in the conjunctival fornix and the lid tarsus, respectively. Basal secretion, so important in keratoconjunctivitis sicca syndromes is measured by a Schirmer test with topical anesthesia to eliminate the afferent arc of the trigeminal nerve. Basal lacrimal secretion has no known efferent nerve supply and usually accounts for the first 8 to 15 mmof wetting in normal eyes. On the other hand, total lacrimal secretion (basal and reflex) is measured without topical