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At least 19 recordsLinked to original sources

PubMed1994

Meniscal tears missed on MR imaging: relationship to meniscal tear patterns and anterior cruciate ligament tears.

OBJECTIVE: MR imaging of the knee is a valuable technique for diagnosing meniscal tears, but some tears found at arthroscopy are not shown on MR imaging. The purpose of this study was to determine whether or not tears were more frequently missed in the presence of an anterior cruciate ligament tear or when tears had certain locations or configurations. MATERIALS AND METHODS: We reviewed the original MR reports and surgical records of 400 patients who had both an MR examination and arthroscopy of the knee. Using chi 2 analysis, we examined how the sensitivity for detecting meniscal tears varied with the presence of a tear of the anterior cruciate ligament, with the location of the tear within the meniscus, and among six configurations of meniscal tears. We also studied whether sensitivity decreased with an increasing delay between MR examination and arthroscopy. RESULTS: In the presence of a tear of the anterior cruciate ligament, the sensitivity decreased from 0.97 to 0.88 (p = .016) for medial meniscal tears and from 0.94 to 0.69 (p = .0005) for lateral tears. The overall sensitivity for lateral meniscal tears was significantly less for posterior (p = .001) and peripheral (p = .005) tears than for other tear locations or configurations. The sensitivities did not significantly differ between tear locations and configurations in the medial meniscus or with an increasing delay until arthroscopy. Patients with a torn anterior cruciate ligament were more likely to have peripheral tears of the medial meniscus (p = .00004) and posterior (p = .0004) and peripheral (p = .04) tears of the lateral meniscus. CONCLUSION: Because of their location and configuration, meniscal tears associated with an anterior cruciate ligament injury are more difficult to detect on MR images than are tears in knees with an intact ligament. If a tear of the anterior cruciate ligament is detected, special attention should be given to the subtle peripheral tears that may be present in either meniscus, but most commonly in the posterior horn of the lateral meniscus. These tears are especially difficult to detect on MR images.

Adult↗

PubMed2000

Comparison of tear sampling techniques for pharmacokinetics analysis: ofloxacin concentrations in rabbit tears after sampling with schirmer tear strips, capillary tubes, or surgical sponges.

This study compared the precision and accuracy of 4 tear sampling methods. In vivo, albino rabbits were treated with single bilateral eye drops ofofloxacin 0.3% solution, 3 hr after which tear samples were collected using capillary tubes (CT), surgical sponges (SS), or tear strips for 15 sec (15sTS) or 60 sec (60sTS). In vitro, CT, SS, and tear strips were spiked with known volumes of ofloxacin solution in order to assess the bioanalytical accuracy of each technique. Ofloxacin levels were quantified by HPLC in all samples. Results showed that tear volumes and ofloxacin masses sampled in vivo depended on sampling method. Tear volume followed the rank order 60sTS > 15sTS > SS > CT. The volume collected by 60sTS exceeded precorneal tear volume. Ofloxacin mass followed the order 60sTS approximately 15sTS > SS > CT. Tear concentrations (mean +/- SD; N = 12) were 3.28 +/- 3.76 microg/g for 60sTS, 10.3 +/- 10.0 microg/g for 15sTS, 9.75 +/- 8.04 microg/g for SS, and 5.83 +/- 3.35 microg/g for CT. In vitro, SS, 15sTS, and 60sTS yielded accuracies of 103-107% and coefficients of variation (CV) < 9%. CT was only 85% accurate with a CV of 31%, indicating incomplete extraction during analysis. We concluded from this study that: 1) rabbit tear sampling by SS was rapid, easy, accurate, precise, and easily analyzable; 2) sampling by CT or 15sTS was accurate, but may require aggressive extraction (for CT) or be affected by tear flow rate (for 15sTS); and 3) tear sampling by 60sTS underestimated actual tear concentrations.

Animals↗

PubMed2004

A comparison of tear volume (by tear meniscus height and phenol red thread test) and tear fluid osmolality measures in non-lens wearers and in contact lens wearers.

PURPOSE: Various measures are available to assess the tear film, yet little specific information is available on how they relate to each other. An exploratory study was undertaken to assess three measures and their relationship in non-contact lens wearers and in contact lens wearers. METHODS: Forty-three young subjects (mean age, 25.0 +/- 3.1 years; 19 men and 24 women) without overt ocular disease were recruited and categorized into four similarly sized groups based on contact lens wear (no lens wear, conventional daily wear hydrogels, silicone hydrogel lenses worn on a continuous basis, and gas-permeable contact lenses). Sets of measures, in random order and from both eyes whenever possible, were made using a phenol red thread (PRT) test over 15 seconds (open eye), biomicroscopy to assess tear meniscus height (TMH) from a perpendicular perspective using a 0.05-mm resolution graticule, and a borosilicate glass micropipette used to collect a 5-microL sample of tears for assessment of osmolality by vapor pressure measures. RESULTS: For the complete group of subjects, the TMH data averaged 0.22 +/- 0.07 mm; the average PRT wetting length was 18.0 +/- 6.1 mm; and the tear osmolality averaged 317 +/- 28 mOsm/kg. The intereye differences averaged 0.04 mm for TMH, 3.7 mm for PRT, and 15 mOsm/kg for tear osmolality. There were no detectable sex-related differences in the measures. Compared with the control group (average, 0.25 mm), the TMH data showed a trend to be lower in daily hydrogel (0.21 mm) and silicone hydrogel (0.20 mm) lens wearers, but not in gas-permeable lens wearers (0.24 mm). PRT data was bimodally distributed, with the control group showing slightly higher (average, 21.1 mm) wetting compared with hydrogel lens wearers (16.7 and 17.4 mm) and gas-permeable lens wearers (average, 17.3 mm). Hydrogel (319 mOsm/kg for both groups) and gas-permeable lens wearers (average, 324 mOsm/kg) had higher tear osmolality measures compared with the control group (average, 305 mOsm/kg). Although some of the differences approached statistical significance, any statistical differences were evident only after outliers were removed. However, on pooling all data, there was a statistically significant positive correlation between TMH and open-eye PRT measures (P < 0.001) and an indication of a negative correlation between open-eye PRT and tear osmolality measures. CONCLUSIONS: Even contemporary contact lens wear can have a small but measurable impact on the precorneal tear film osmolality or volume. The changes are internally consistent and, overall, support the idea that the PRT test provides a useful measure of tear meniscus volume.

Adolescent↗

PubMed2006

Clinical outcome of anterior shoulder instability with capsular midsubstance tear: a comparison of isolated midsubstance tear and midsubstance tear with Bankart lesion.

To analyze the clinical outcomes of patients with a midsubstance capsular tear for anterior shoulder instability, 21 shoulders with a midsubstance tear were reviewed. There were 7 isolated midsubstance tears (group I) and 14 combined midsubstance tears with Bankart lesions (group II). The Rowe score averaged 92.3 points with 6 excellent and 1 good one in group I. Group II scored 86.3 points with 8 excellent, 3 good, 2 fair, and 1 poor (P = .184). The Rowe score averaged 89.8 points for the cases with an arthroscopic procedure and 86.9 points with an open repair (P = .542). At the last follow-up, forward elevation increased by 6 degrees in group I and 8 degrees in group II (P = .432). External rotation decreased by 8 degrees and 16 degrees , respectively (P = .150). The clinical outcomes of anterior instability with a midsubstance tear were good in both groups. The loss of external rotation was greater in the cases with combined midsubstance tears and Bankart lesions than in those with an isolated midsubstance tear.

Adolescent↗

PubMed2001

Clinicopathological correlation of retinal pigment epithelial tears in exudative age related macular degeneration: pretear, tear, and scarred tear.

AIMS: To analyse the histopathology of vascularised pigment epithelial detachments and tears of the retinal pigment epithelium (RPE) in age related macular degeneration (AMD). METHODS: The light microscopic architecture of 10 surgically removed subretinal specimens-three vascularised pigment epithelial detachments, four recent tears, and three scarred tears as a manifestation of AMD-were studied and correlated with the angiographic findings. RESULTS: Recent tears: a large fibrovascular membrane was found to be originally situated in Bruch's membrane. About half of the surface of the fibrovascular tissue was denuded of RPE and diffuse drusen. The RPE and diffuse drusen had retracted and rolled up, covering a neighbouring part of the intra-Bruch's fibrovascular membrane. The rolled up RPE and diffuse drusen were not interspersed with fibrovascular tissue but lay superficial to the intra-Bruch's fibrovascular membrane itself. Scarred tears: a collagen capsule surrounded the rolled up diffuse drusen and RPE. Fibrovascular tissue was found inside the rolled up material, predominantly at its choroidal side. CONCLUSION: The area of choroidal neovascularisation associated with a vascularised pigment epithelial detachment and a tear of the RPE may be larger than was hitherto thought or indicated by fluorescein angiography. This neovascular tissue may be present within the bed of the RPE tear, as well as at the site of the scrolled up RPE.

Aged↗

PubMed1997

Single-tendon tears of the rotator cuff. Evaluation and treatment of subscapularis tears and principles of treatment for supraspinatus tears.

Successful surgical treatment of single-tendon tears, which involve the supraspinatus or the subscapularis requires careful attention to technical details. In supraspinatus tears, careful mobilization and secure repair of the tendon will usually give a good outcome. In subscapularis tears, the diagnosis is not difficult if one carefully evaluates the patient for the classic pathognomonic findings of such a tear. If the tear is confirmed by CT or MR imaging and an acute repair is performed, the outcome is usually satisfactory.

Arthroscopy↗

PubMed1992

Reliability of the tear break-up time technique of assessing tear stability and the locations of the tear break-up in Hong Kong Chinese.

The measurement of tear break-up time (TBUT) in assessing stability of the tear film is somewhat controversial, even though the technique is widely used. We examined reliability of the technique within and among examiners and conclude that measurements of TBUT can be made reliably; full-beam observation of the cornea is preferable to scanning the cornea with a narrow slit in making the measurements. There may be differences in TBUT measurements made in the same subjects among examiners, but these differences are smaller with more experienced practitioners. In the Hong Kong Chinese (HK-Chinese), tear break-up appears to be more likely to first occur in the inferior periphery of the cornea. In this population mean TBUT is about 7.20 s; assuming a Gaussian distribution of TBUT values, 2.1 s should be adopted as the lower limit for normal TBUT in HK-Chinese.

Adolescent↗

PubMed1995

Correlation of tear clearance rate and fluorophotometric assessment of tear turnover.

BACKGROUND: The study sought to determine dynamic changes and theoretical bases of a clinical diagnostic test, the tear clearance rate. METHODS: Thirty four healthy subjects ranging in age from 22 to 84 years underwent examination of tear clearance rate, the Schirmer test with anaesthesia, as well as fluorophotometric measurement of tear turnover, tear volume, and tear flow. By applying 0.5% fluorescein into the conjunctival sac and subsequently measuring colour fades on a Schirmer strip, the tear clearance rate for assessing tear drainage was divided into nine grades. The results of the tear clearance rate were compared with those of the basal tear turnover and tear flow obtained from fluorophotometry. RESULTS: Significant relations were found between the tear clearance rate and the basal tear turnover or tear flow (r = 0.91 and 0.79, respectively, p = 0.0001). Considering the grades of progression from low to high, each grade of tear clearance rate showed a 12.5% increase in basal tear turnover (3.59%/min) and tear flow (0.38 microliter/min). There was no significant correlation between age and the basal tear turnover, tear volume, tear flow, or the tear clearance rate. CONCLUSION: The tear clearance rate is proposed as a simple and useful way to estimate basal tear turnover and tear flow, and measure tear drainage indirectly.

Adult↗

PubMedDate not supplied

Analysis of tear uptake by the Schirmer tear test strip in the canine eye.

OBJECTIVE: To analyze the uptake of tears in a Schirmer tear test (STT) in vitro and in vitro. MATERIALS AND METHODS: Uptake of fluid by Schirmer tear test strips was studied in vitro by examining fluid uptake over time from an unlimited fluid supply as well as with specific fluid volumes applied to the test strip. Uptake of fluid by Schirmer tear test strips was evaluated in a population of 100 ophthalmologically normal dogs together with a group of 40 dogs with tear film abnormalities such as keratoconjunctivitis sicca (KCS) or epiphora. Each animal was given a full ophthalmic examination followed by a standard Schirmer tear test extended over between 3 and 5 min with the STT reading recorded every 5 s and plotted over time. To determine the effect of ocular irritation by the test strip, uptake of tears by test strips was determined before and after topical anesthesia in 20 dogs. RESULTS: In vitro examination of fluid uptake by the STT strips showed an initial rapid uptake followed by a gradual reduction in rate of uptake. Temporal evaluation of STT in vivo showed a similar rapid initial uptake of tear fluid, followed in the majority of cases by a sudden change to a steady state uptake of fluid. The initial gradient was 29.3 +/- 16.9 mm/min followed by a steady state uptake of 5.2 +/- 2.3 mm/min in normal dogs and 1.9 +/- 1.3 mm/min in dogs with KCS. This corresponds to a steady state tear turnover of 7.8 +/- 3.4 microL/min in normal dogs and 2.8 +/- 1.9 microL/min in animals with KCS. Dogs with nasolacrimal blockage and resultant epiphora showed a high initial gradient but final gradients were not statistically different from those of normal dogs. Discussion and conclusions Temporal evaluation of tear uptake by the STT shows substantial differences in rate of tear uptake at different time-points during the period of the test. RESULTS: of this study suggest that the initial rapid rise in STT value represents uptake from the tear lake followed by a slower tear uptake of tears from steady state tear production. Temporal examination of the Schirmer tear test allows a more precise evaluation of tear production than the standard STT measuring tear uptake in 1 min, together with estimation of the contribution to the test strip tear uptake of tears from the residual tear lake volume and those from continual tear production.

Absorption↗

PubMed1983

Studies of human tear proteins--2. Analysis by crossed immunoelectrophoresis of tears from diseased eyes.

By filter paper strips, tears were collected from patients with diseases in the anterior ocular segment and analysed by crossed immunoelectrophoresis. Their crossed immunoelectrophoretic patterns were compared with those of normal subjects. Tear proteins from Sjögren's syndrome. Mikulicz's disease and tumor of the lacrimal gland showed abnormal patterns by crossed immunoelectrophoresis. Tears were collected from patients with lacrimal gland tumor after resection of the tumors. Ten tear-specific proteins were more decreased in these patients than in normal subjects. Serum proteins in the tears of these patients were increased, but secretory IgA (s-IgA) showed no change. A patient with symblepharon showed a marked decrease of both tear-specific proteins and s-IgA. Tears from patients wit epidemic keratoconjunctivitis (EKC), vernal conjunctivitis, herpes simplex keratitis (HSK) and adult inclusion conjunctivitis were analyzed. No remarkable change in tear-specific proteins could be noticed between tears from a case with an early stage of EKC or slight inflammation of the conjunctivitis and tears from the fellow unaffected eye. However, an increase was noted in serum proteins of the diseased eye. The tears collected from a case with severe EKC showed a decrease of tear-specific proteins, but an increase of serum proteins; especially s-IgA showed a significant increase. Tears from patients with EKC, HSK, vernal conjunctivitis and adult inclusion conjunctivitis showed differences in the immunoelectrophoretic patterns of tear proteins according to the severity and duration of the inflammation, as well as the amount of tears secreted. After due consideration of the analysis of tear proteins from some diseases of the anterior ocular segment, the following secretory sites of tear proteins under normal conditions were projected. The 10 tear-specific proteins reported in the previous paper are thought to be largely secreted from the main lacrimal gland. s-IgA is mainly secreted through the excretory ducts of the main lacrimal gland. Serum proteins in the tears are thought to come through the conjunctiva.

Adolescent↗

PubMed1998

In vivo tear-film thickness determination and implications for tear-film stability.

PURPOSE: Previous measurements of tear-film thickness in vivo are limited and cannot be easily applied in a clinical setting. A novel technique to measure tear-film thickness indirectly is introduced here, requiring only a slit lamp, video camera, and computer. A recent fluid mechanical theory relates tear-film thickness h, to the tear meniscus radius R, tear surface tension or, tear viscosity mu, and upper lid velocity U. This theory yields the result that h/R = 2.12 (microU/sigma)2/3. All parameters except h/R are taken as known physical constants, and R was measured for each subject, allowing the above equation to establish h. Tear-film breakup was also evaluated and correlated with tear-film thickness. METHODS: A clinical study was performed in which aqueous tear-film thickness was determined for 45 subjects, including 24 non-lens subjects, 15 hydrogel contact lens wearers, and 6 RGP lens wearers. R was measured by instilling fluorescein dye in the form of an eyedrop and videotaping the tear meniscus in profile. Tear-film breakup was videotaped through the ocular port of the slit lamp and evaluated based on a severity scale. RESULTS: Aqueous tear-film measurements are in the same range as literature values, with most measured values falling between 6 and 12 microm. Average tear-film thicknesses for non-lens, hydrogel, and RGP subjects are 10.4, 6.5, and 5.8 microm, respectively. Tear-film breakup is most severe in subjects with thin tear films, especially in contact-lens wearers. CONCLUSIONS: Tear-film thickness is an important parameter that varies among individuals. These variations correlate with differences in tear-film stability.

Adult↗

PubMed2001

The effect of punctal occlusion on tear production, tear clearance, and ocular surface sensation in normal subjects.

PURPOSE: To evaluate the effect of temporary punctal occlusion on tear production, tear clearance, and ocular surface sensation in normal subjects. METHODS: Noncomparative interventional case series. Punctal occlusion with silicone punctal plugs was performed on nine normal subjects without complaints of ocular irritation and no known history of ocular surface disease. The lower punctum of both eyes was occluded in five subjects. The upper and lower puncta of only one eye were occluded in four subjects. Corneal and conjunctival sensations were measured with the Cochet-Bonnet anesthesiometer. Tear fluorescein clearance was evaluated with a CytoFluor II fluorophotometer by measuring the fluorescein concentration in minimally stimulated tear samples collected from the inferior tear meniscus 15 minutes after instillation of fluorescein. Schirmer test was performed without anesthesia. The tests were performed at days 0, 1, 3, 7, and 14 to 17 after punctal occlusion. Relationships were analyzed with linear regressions, and a quadratic term was used to model a return to preocclusion levels. Paired t test was used to study the change in tear fluorescein concentration. RESULTS: In subjects who had the lower puncta of both eyes occluded, conjunctival sensation decreased in both eyes (right eye, P =.008; left eye, P =.003), but there was no change in corneal sensation. Their tear fluorescein clearance did not show a significant change from baseline (P =.90). However, a decrease in Schirmer test scores approached statistical significance (P =.056). In subjects with both puncta of only one eye occluded, we noted a decrease in corneal sensation (occluded eye, P =.042; nonoccluded eye, P =.036), conjunctival sensation (occluded, P =.001; nonoccluded, P =.060), and Schirmer scores (occluded, P =.022; nonoccluded, P =.011). Linear regression did not show a significant change in tear fluorescein clearance for either eye (occluded, P =.28; nonoccluded, P =.44). However, paired t test showed a significant worsening of tear clearance in the occluded eye from day 0 to day 3 (P =.001) followed by a subsequent improvement in tear clearance from day 3 to the end of the study period (P =.045). Paired t test did not reveal any significant changes in tear clearance in the nonoccluded eye. The quadratic term of the linear regression model demonstrated an increase toward preocclusion levels that approached statistical significance for corneal sensation (occluded, P =.053; nonoccluded, P =.099). It was statistically significant for conjunctival sensation (occluded, P =.001; nonoccluded, P =.045) and Schirmer scores (occluded, P =.047; nonoccluded, P =.044). CONCLUSIONS: Temporary punctal occlusion in normal subjects decreases tear production and ocular surface sensation. Our findings suggest that in addition to blocking tear drainage, punctal occlusion may affect the ocular surface/lacrimal gland interaction. These effects were more pronounced in subjects with both upper and lower puncta occluded. In normal subjects, there appears to be an autoregulatory mechanism to return tear production, tear clearance, and ocular surface sensation to preocclusion levels 14 to 17 days after punctal occlusion.

Conjunctiva↗

PubMed2007

Posterior horn lateral meniscal tears simulating meniscofemoral ligament attachment in the setting of ACL tear: MRI findings.

PURPOSE: We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. MATERIALS AND METHODS: Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student's t test and Fisher's exact test. RESULTS: Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). CONCLUSION: Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear.

Adolescent↗

PubMed1995

[Measurement of pH, time-dependent-changes in pH, [Na+], and [K+] in human tears--comparison between normal subjects, subjects with decreased tear secretion, and contact lens wearers].

In order to investigate basic mechanisms of tear secretion and tear gland dysfunction, the pH, its time-dependent change (delta pH), [Na+], and [K+] of basal and reflex tears were measured. Subjects were humans with normal tear secretion or decreased tear secretion, and hard contact lens (HCL) wearers. Reflex tears were collected by administration of distilled water into the conjunctival sacs of the fellow eyes to study the secretory function of normal human lacrimal glands. In the clinical part of this study, reflex tears were collected from subjects before and after tasting horseradish paste. The [K+] and delta pH of the normal human reflex tears were significantly higher than in the basal tears according to the degree of stimulus until medium range. This suggests the presence of K(+)- and HCO(3-)-dependent secretory mechanism in the lacrimal glands. In the patients with decreased tear secretion, [K+] data of reflex tears were either higher than or equivalent to the data for basal tears. Therefore, the difference in amplitude of the stimulus-induced increase of tear [K+] suggests that there are two or more types of lacrimal gland dysfunction in patients with decreased tear secretion.

Adolescent↗

PubMed2003

Association of biceps tendon tears with rotator cuff abnormalities: degree of correlation with tears of the anterior and superior portions of the rotator cuff.

OBJECTIVE: This study was performed to examine the relationship and association of abnormalities seen in the long head of the biceps brachii tendon to abnormal findings in the rotator cuff. MATERIALS AND METHODS: One hundred eleven patients underwent MR imaging for shoulder pain followed by arthroscopic or open shoulder surgery from January 1997 to December 2000. Patients were identified by a retrospective search, and all consecutive patients having undergone both MR imaging and surgery were included in the patient cohort. Official MR imaging interpretations were compared with operative reports, and all findings were recorded. RESULTS: Twenty-three patients were identified with partial- or full-thickness tears of the long head of the biceps tendon. The sensitivity, specificity, and accuracy of unenhanced MR imaging of the shoulder for detecting these bicipital tears were 52%, 86%, and 79%, respectively. When a tear was present in the biceps tendon, the prevalence of supraspinatous, infraspinatus, and subscapularis tendon tears was 96.2%, 34.6%, and 47.1%, respectively. Patients with biceps tendon tears were significantly more likely to also have subscapularis tendon tears (p < 0.0001) and supraspinatous tendon tears (p < 0.008) than those patients who did not have biceps tendon tears. No significant relationship was found between the presence or absence of a biceps tendon tear and the presence or absence of a infraspinatus or teres minor tendon tear (p = 0.17). CONCLUSION: Tears of the long head of the biceps tendon have a statistically significant association with tears of the anterior and superior rotator cuff and are highly correlated with tears of the supraspinatous and subscapularis tendons. When tears of these tendons are detected, specific attention directed toward the long biceps tendon is warranted to characterize the status of this structure that provides additional stability to the shoulder joint.

Adolescent↗

PubMed1997

Relationship between tear-meniscus parameters and tear-film breakup.

PURPOSE: Several flaws exist with the lipid-diffusion model for tear-film breakup. The aim of this study was to test an alternative model of tear-film rupture in which the negative hydrostatic pressure in each tear meniscus (related to the tear-meniscus radius of curvature) is proposed to influence the formation of breaks in the tear film. METHODS: Measurements of noninvasive breakup time (NIBUT) and tear-meniscus radius of curvature, height, width, and cross-sectional area (TMC, TMH, TMW, and XSA) were made for 15 aqueous-deficient dry-eye and 15 age-matched control subjects. An optic section of the inferior tear meniscus (colored with a minute volume of fluorescein) was photographed at x120 magnification, and images were computer analyzed. RESULTS: A significant positive correlation was found between log NIBUT and TMC (r2 = 0.141; p < 0.05). Furthermore, all subjects with TMC < 0.340 mm had NIBUT < 15 s, and two thirds of subjects with TMC > 0.340 mm had NIBUT > 15 s. There was a moderate linear relationship between TMH and log NIBUT, indicating an association between tear volume and tear stability. TMC, TMH, and tear meniscus XSA measurements all showed good reliability. CONCLUSIONS: The association between highly curved tear menisci and rapid tear-film breakup times is consistent with the meniscus model of tear-film rupture. However, a causal relationship has yet to be established.

Administration, Topical↗

PubMedDate not supplied

Associated injuries in pediatric and adolescent anterior cruciate ligament tears: does a delay in treatment increase the risk of meniscal tear?

PURPOSE: To evaluate the incidence of associated injuries and meniscal tears in children and adolescents with anterior cruciate ligament (ACL) tears, we performed a retrospective review of patients, age 14 and younger, who were treated surgically at our institution. TYPE OF STUDY: Retrospective review. METHODS: We reviewed 39 patients (30 girls, 9 boys) with an average age of 13.6 years (range, 10 to 14 years) who underwent surgical treatment of the ACL; 24 right knees and 15 left knees were treated. Of the injuries treated, 24 occurred by a twisting mechanism, 10 were the result of contact, and 5 occurred from hyperextension. Thirty-five injuries occurred during sports activities, and 2 were sustained in motor vehicle accidents. The mean duration from injury to operative treatment was 101 days (range, 7 to 696 days). Injuries were classified as acute (n = 17) if surgery was performed within 6 weeks of injury and chronic (n = 22) if surgery was performed after 6 weeks from injury. Relationships between medial and lateral meniscal injuries and the time from injury to surgery were analyzed, and the 2 groups, acute and chronic, were compared. Finally, the patterns of meniscal injury were compared. RESULTS: Twenty-six patients had associated injuries (10 medial meniscal tears, 15 lateral meniscal tears, 3 medial collateral ligament tears, and 1 fractured femur). The association between medial meniscal tears and time from injury to surgery was highly statistically significant (P =.0223). There was no statistical significance between the incidence of lateral meniscal tears and time. Medial meniscal tears were more common in the chronic group (36%) than in the acute group (11%), whereas lateral meniscal tears were found with equal frequency. Medial meniscal tears that required surgical treatment (either partial excision or repair) were more common in the chronic group, and lateral meniscal tear patterns were equally distributed. CONCLUSIONS: Evidence from this study supports the contention that associated injuries are common in young individuals with ACL tears. Furthermore, the data also show that a delay in surgical treatment was associated with a higher incidence of medial meniscal tears.

Accidents, Traffic↗

PubMed2004

Development of a rabbit model of tear film instability and evaluation of viscosity of artificial tear preparations.

OBJECTIVE: The purposes of this study were to establish a quantitative method for evaluating rabbit tear film status and investigate the efficacy of artificial tear preparations through ocular surface bathing or eye drop application. METHODS: The rabbit tear film was evaluated using a noninvasive specular reflection video recording system. The appearance of a tear break area (TBA) on the tear film images (7.4 mm2/mm) after 30 seconds of eye opening was quantified by image analysis. To induce disruption of the rabbit tear film, the ocular surface was challenged for 60 minutes with 1 ppm hypochloric acid (HOCl). Immediately after irrigation, artificial tear preparations composed of viscosity agents sodium hyaluronate (SH), hydroxypropylmethycellulose (HPMC), hydroxyethylcellulose (HEC), or chondroitin sulfate (CS) were applied to the rabbit eye through ocular surface bathing or eye drop application, and the recovery of the disrupted tear film was compared for each preparation. RESULTS: A dramatic increase in TBA was observed immediately after the ocular surface was challenged with HOCl, and it returned to the initial level after 6 hours. Immediately after ocular surface bathing and eye drop application, a dramatic recovery of TBA was observed in all the test solution-treated eyes. One hour after treatments, prolonged amelioration of the tear film instability was observed after ocular surface bathing, but not by eye drop application, with the artificial tear preparations composed of HPMC or SH. CONCLUSION: Ocular surface bathing with artificial tear preparations composed of a suitable viscosity agents could be useful in managing tear film instability.

Animals↗