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Effects of Lens Thickness and Water Content on Dryness and Tear dynamics on Soft Contact Lens
TEAR FILM & OCULAR SURFACE EFFECTS OF LENS THICKNESS AND WATER CONTENT ON DRYNESS AND TEAR DYNAMICS ON SOFT CONTACT LENS. Kunio Maruyama, Norihiko Yokoi, Hisayo Higashihara, Shigeru Kinoshita. Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
DEGRADATION OF THE TEARFILM GEL LAYER. Elizabeth Matthews,1 Anthony P. Corfield,2 J. Peter Gierow,3 Stephen D Carrington.1 Faculty of Veterinary Medicine, University College Dublin, Ireland,1 Mucin Research group, Division of Medicine, University of Bristol, UK,2 Department of Natural Sciences,University of Kalmar, Sweden.3
Purpose. Dry eye symptoms are often associated with soft contact lens (SCL) wear and are possibly affected by the materials of SCL. This study aimed to explore the effect of central thickness (CT) and water content (WC) of SCL on dryness of subjects and tear dynamics on SCL. Methods. Eleven all male daily SCL wearers [aged 23.5 ± 5.2 (mean ± SD)] were enrolled in this study. Three different types of SCL [SCL-a (CT: 0.16mm, WC: 72.0%), SCL-b (CT: 0.05mm, WC: 72.0%), SCL-c (CT: 0.16mm, WC: 37.5%)], which were identical material and similar design throughout the lens, but were different in the CT and WC, were applied only to the right eye of subjects under the standardized condition (air temperature: 15°C, relative humidity: 20%). Tear volumes were evaluated by measuring tear meniscus radius (TMR) during SCL wear using a video meniscometer (Yokoi, Cornea, 2000). Tear interference patterns on the CL (TIPCL) were graded into one of five original grades (Maruyama, IOVS, 2004; Increased grades for thinner film) using a video interferometer (Yokoi, AJO, 1996), which was also used for measuring non-invasive tear film breakup time (NIBUT, seconds) on SCLs. Ocular dryness during SCL wear were scored (score: 0-3). In vitro, captive bubble method was applied to measure contact angle (CA, degree) of SCL-a and SCL-b to evaluate wettability of the lenses. Results. In all evaluations, no significant differences were found between SCL-a and SCL-b. Also in TMR, no significant difference was found between SCL-a and SCL-c. However, SCL-c showed significantly lower values in TIPCL grades, than those of SCL-a (SCL-c: 2.0 ± 0.6, SCLa: 2.8 ± 0.8; p<0.05), significantly longer values in NIBUT than those of SCL-a (SCL-c: 3.7 ± 2.7, SCL-a: 2.3 ± 1.6; p<0.05) and significantly lower in dryness scores than those of SCL-a (SCL-c: 0.9 ± 0.7, SCL-a: 1.6 ± 0.9; p<0.05). In CA, SCL-c showed significantly lower values than those of SCL-a (24.6 ± 2.2, 33.0 ± 2.6, respectively) (p<0.01). Conclusions. Dryness of subjects and tear dynamics on SCL were not considerably affected by CT, but were affected by WC; and it was found that dryness of subjects and tear stability on SCL increases in higher WC.
Purpose. A specialised viscoelastic mucus gel surmounts the ocular surface and forms part of the pre-ocular tear film. This is variously derived from the corneal and conjunctival epithelium, and the secretions of the lacrimal gland. Its most significant gel-forming component is the mucin MUC5AC, produced by conjunc-tival goblet cells. Secreted mucins are a class of large hydrophilic glycoprotein polymers, which are the major functional component of all mucus gels. At the ocular surface, they function in lubrication, tissue hydration, and the inhibition of pathogen adherence. A fundamental property of mucus gels is that they ‘turn over’: thereby cleansing the surface upon which they lie. The dual requirements of controlling ocular surface microbial colonisation, and facilitating the elimination of mucus gel via the small bore of the lacrimal puncta, suggest that mucin degrada-tion is a physiological requirement in the tear film. This study examines the role of glycosidases secreted by the lacrimal gland in their degradation and turnover. Methods. Aspirates of ocular surface mucus were purified from rabbits, using a combination of chaotropic dispersal, density gradient centrifugation, and gel filtra-tion. Supernatant from carbochol-stimulated primary cultures of rabbit lacrimal acinar cells, and whole human tears, were assayed for glycosidase activity using a range of synthetic substrates. These fluids were also used as enzyme sources to determine their activity in degrading purified rabbit ocular mucin: as demonstrated on size exclusion profiles. Identical incubations were conducted in the presence of specific glycosidase inhibitors. Results. Mucin degrading (mucinase) activity was demonstrated by a marked reduction in molecular weight of incubated mucins over controls. This reduction was substantially reduced in the presence of glycosidase inhibitors. Conclusions This study provides evidence that glycosidases secreted by the lacrimal gland play a role in mucus gel turnover at the ocular surface. The most relevant activities are consistent with the saccharide content of ocular mucins. Support: UCD presidents research grant THE EFFICACY OF A NEW EYE STEAMER DEVICE ON TEAR FUNCTIONS OF PATIENTS WITH OBSTRUCTIVE MEIBOMIAN GLAND DISEASE. Yukihiro Matsumoto,1 Murat Dogru,1 Eiki Goto,2 Reiko Ishida,3 Takashi Kojima,4 Tatsuya Onguchi,1 Yukiko Yagi1 Jun Shimazaki,1 Kazuo Tsubota.5 1Tokyo Dental College, Chiba, Japan; 2Iidabashi Eye Clinic,Tokyo,Japan; 3Shizuoka Eye Clinic, Shizuoka, Japan; 4Nagoya Chukyo Social Insurance Hospital, Nagoya, Japan ; 5Keio University School of Medicine, Tokyo, Japan. Purpose. To evaluate the safety and short term effects of an original eye steamer device on tear functions and ocular surface of patients with obstructive meibomian gland disease (MGD). Methods. Fifteen patients with obstructive MGD and 12 healthy volunteers were recruited in this prospective interventional clinical trial. The eye steamer device was applied to the eyes of the subjects for 10 minutes. Temperature of the eye lids and corneas were measured with an infrared radiation thermometer. Symptoms of ocular fatigue were scored using a visual analog scale (VAS). Schirmer test , tear film break up time (BUT), DR-1R tear film lipid layer interferometry, and corneal fluorescein staining were also performed before and after the application of the eye steamer. Results. VAS scores of ocular fatigue improved significantly with the application of eye steamer. The mean corneal surface and eye lid temperatures showed significant elevation within safe limits with steam application. The mean BUT prolonged significantly in the patients. DR-1R tear film lipid layer interference showed evidence of lipid expression in the patients and controls with thickening of the tear film lipid layer after 10 minutes of eye steamer use. Conclusion. Eye steamer use provided symptomatic relief of ocular fatigue and improvement of tear stability in patients with MGD. Eye steamer device seems to be a safe and promising alternative in the treatment of MGD.
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THE OCULAR SURFACE / JANUARY, 2005, VOL. 3, NO. 1 / SUPPLEMENT
DEGRADATION OF THE TEARFILM GEL LAYER. Elizabeth Matthews,1 Anthony P. Corfield,2 J. Peter Gierow,3 Stephen D Carrington.1 Faculty of Veterinary Medicine, University College Dublin, Ireland,1 Mucin Research group, Division of Medicine, University of Bristol, UK,2 Department of Natural Sciences,University of Kalmar, Sweden.3
Purpose. Dry eye symptoms are often associated with soft contact lens (SCL) wear and are possibly affected by the materials of SCL. This study aimed to explore the effect of central thickness (CT) and water content (WC) of SCL on dryness of subjects and tear dynamics on SCL. Methods. Eleven all male daily SCL wearers [aged 23.5 ± 5.2 (mean ± SD)] were enrolled in this study. Three different types of SCL [SCL-a (CT: 0.16mm, WC: 72.0%), SCL-b (CT: 0.05mm, WC: 72.0%), SCL-c (CT: 0.16mm, WC: 37.5%)], which were identical material and similar design throughout the lens, but were different in the CT and WC, were applied only to the right eye of subjects under the standardized condition (air temperature: 15°C, relative humidity: 20%). Tear volumes were evaluated by measuring tear meniscus radius (TMR) during SCL wear using a video meniscometer (Yokoi, Cornea, 2000). Tear interference patterns on the CL (TIPCL) were graded into one of five original grades (Maruyama, IOVS, 2004; Increased grades for thinner film) using a video interferometer (Yokoi, AJO, 1996), which was also used for measuring non-invasive tear film breakup time (NIBUT, seconds) on SCLs. Ocular dryness during SCL wear were scored (score: 0-3). In vitro, captive bubble method was applied to measure contact angle (CA, degree) of SCL-a and SCL-b to evaluate wettability of the lenses. Results. In all evaluations, no significant differences were found between SCL-a and SCL-b. Also in TMR, no significant difference was found between SCL-a and SCL-c. However, SCL-c showed significantly lower values in TIPCL grades, than those of SCL-a (SCL-c: 2.0 ± 0.6, SCLa: 2.8 ± 0.8; p<0.05), significantly longer values in NIBUT than those of SCL-a (SCL-c: 3.7 ± 2.7, SCL-a: 2.3 ± 1.6; p<0.05) and significantly lower in dryness scores than those of SCL-a (SCL-c: 0.9 ± 0.7, SCL-a: 1.6 ± 0.9; p<0.05). In CA, SCL-c showed significantly lower values than those of SCL-a (24.6 ± 2.2, 33.0 ± 2.6, respectively) (p<0.01). Conclusions. Dryness of subjects and tear dynamics on SCL were not considerably affected by CT, but were affected by WC; and it was found that dryness of subjects and tear stability on SCL increases in higher WC.
Purpose. A specialised viscoelastic mucus gel surmounts the ocular surface and forms part of the pre-ocular tear film. This is variously derived from the corneal and conjunctival epithelium, and the secretions of the lacrimal gland. Its most significant gel-forming component is the mucin MUC5AC, produced by conjunc-tival goblet cells. Secreted mucins are a class of large hydrophilic glycoprotein polymers, which are the major functional component of all mucus gels. At the ocular surface, they function in lubrication, tissue hydration, and the inhibition of pathogen adherence. A fundamental property of mucus gels is that they ‘turn over’: thereby cleansing the surface upon which they lie. The dual requirements of controlling ocular surface microbial colonisation, and facilitating the elimination of mucus gel via the small bore of the lacrimal puncta, suggest that mucin degrada-tion is a physiological requirement in the tear film. This study examines the role of glycosidases secreted by the lacrimal gland in their degradation and turnover. Methods. Aspirates of ocular surface mucus were purified from rabbits, using a combination of chaotropic dispersal, density gradient centrifugation, and gel filtra-tion. Supernatant from carbochol-stimulated primary cultures of rabbit lacrimal acinar cells, and whole human tears, were assayed for glycosidase activity using a range of synthetic substrates. These fluids were also used as enzyme sources to determine their activity in degrading purified rabbit ocular mucin: as demonstrated on size exclusion profiles. Identical incubations were conducted in the presence of specific glycosidase inhibitors. Results. Mucin degrading (mucinase) activity was demonstrated by a marked reduction in molecular weight of incubated mucins over controls. This reduction was substantially reduced in the presence of glycosidase inhibitors. Conclusions This study provides evidence that glycosidases secreted by the lacrimal gland play a role in mucus gel turnover at the ocular surface. The most relevant activities are consistent with the saccharide content of ocular mucins. Support: UCD presidents research grant THE EFFICACY OF A NEW EYE STEAMER DEVICE ON TEAR FUNCTIONS OF PATIENTS WITH OBSTRUCTIVE MEIBOMIAN GLAND DISEASE. Yukihiro Matsumoto,1 Murat Dogru,1 Eiki Goto,2 Reiko Ishida,3 Takashi Kojima,4 Tatsuya Onguchi,1 Yukiko Yagi1 Jun Shimazaki,1 Kazuo Tsubota.5 1Tokyo Dental College, Chiba, Japan; 2Iidabashi Eye Clinic,Tokyo,Japan; 3Shizuoka Eye Clinic, Shizuoka, Japan; 4Nagoya Chukyo Social Insurance Hospital, Nagoya, Japan ; 5Keio University School of Medicine, Tokyo, Japan. Purpose. To evaluate the safety and short term effects of an original eye steamer device on tear functions and ocular surface of patients with obstructive meibomian gland disease (MGD). Methods. Fifteen patients with obstructive MGD and 12 healthy volunteers were recruited in this prospective interventional clinical trial. The eye steamer device was applied to the eyes of the subjects for 10 minutes. Temperature of the eye lids and corneas were measured with an infrared radiation thermometer. Symptoms of ocular fatigue were scored using a visual analog scale (VAS). Schirmer test , tear film break up time (BUT), DR-1R tear film lipid layer interferometry, and corneal fluorescein staining were also performed before and after the application of the eye steamer. Results. VAS scores of ocular fatigue improved significantly with the application of eye steamer. The mean corneal surface and eye lid temperatures showed significant elevation within safe limits with steam application. The mean BUT prolonged significantly in the patients. DR-1R tear film lipid layer interference showed evidence of lipid expression in the patients and controls with thickening of the tear film lipid layer after 10 minutes of eye steamer use. Conclusion. Eye steamer use provided symptomatic relief of ocular fatigue and improvement of tear stability in patients with MGD. Eye steamer device seems to be a safe and promising alternative in the treatment of MGD.
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THE OCULAR SURFACE / JANUARY, 2005, VOL. 3, NO. 1 / SUPPLEMENT