Biomedical subjects

N X Nguyen

Publications and source records attributed to N X Nguyen.

At least 55 records · Page 3Linked to original sources

PubMed1997

The effect of stimulus size on human cortical potentials evoked by chromatic patterns.

The effect of stimulus size on the pattern onset-offset visual evoked potential elicited with stimuli of two different wavelengths is studied under intensive yellow adaptation: (1) The onset response obtained with a 460 nm pattern is of negative polarity (N1) and saturates in amplitude with a stimulus radius of 7 deg. The onset response obtained with a 550 nm pattern is of positive polarity and continues to increase up to the maximum size (32.2 deg). (2) The peak time of N1 (460 nm) decreases with increasing stimulus size, that of P1 (550 nm) remains constant. These results are discussed as reflecting either varying retinal and brain anatomy, or cone activity, color-opponent activity, or luminance contrast activity.

Adaptation, Physiological↗

PubMed1997

[Tyndallometry and cell count in the anterior chamber in retinal detachment].

BACKGROUND: Aim of this study was the investigation of changes of aqueous flare and cells in eyes with retinal detachment. PATIENTS AND METHODS: We examined 62 eyes of 61 patients with retinal detachment (56 eyes with rhegmatogenous retinal detachment, 6 eyes with traction retinal detachment; 51 eyes without and 11 eyes with clinical signs of proliferative vitreoretinopathy (PVR) stage C) with the laser flare-cell meter (LFCM) and compared the results with clinical findings and with the results of a control group. RESULTS: The flare values as well as the cell count of all eyes with retinal detachment were significantly elevated (p < 0.0001) in comparison to those of the control group. In eyes with PVR a significant elevation of flare values in comparison to eyes without PVR appeared (p = 0.0052). A slight correlation was found between the extension of the detachment and the flare values and the cell count, respectively. In cases with rhegmatogenous retinal detachment a significant elevation of the cell count was found if the largest break was localized in the upper hemisphere (p = 0.03) or if the macula was affected (p = 0.02). In rhegmatogenous retinal detachment, the cell count correlated slightly with the age of the patients (r = 0.3, p = 0.02), and flare values correlated with the height of the detachment (r = 0.28, p = 0.04). CONCLUSIONS: Our results demonstrate a breakdown of the blood-ocular barriers in eyes with retinal detachment and an elevation of corpuscular elements in aqueous as manifestations of pseudouveitis. In eyes with PVR the alteration of blood-ocular barriers seems to be more extensive than in eyes without PVR indicating a possible role of the LFCM for early detection of PVR.

Adolescent↗

PubMed1997

Pseudoexfoliation syndrome and secondary cataract.

AIM/BACKGROUND: The pseudoexfoliation (PEX) syndrome is frequently associated with impairment of the blood-aqueous barrier. This study analysed if this might stimulate secondary cataract following cataract extraction. METHODS: This historical cohort study included 197 eyes of 197 patients (99 with and 98 without PEX) that underwent extracapsular cataract extraction with posterior chamber lens implantation (PMMA optic) between 1985 and 1991. Secondary cataract was defined as opacification of the axial posterior capsule and decrease of visual acuity by two or more lines. Mean follow up was 23.8 months. For statistical analysis, the Kaplan-Meier method and multivariate Cox regression analysis were used. RESULTS: Secondary cataract was observed within 24 months in 35% (SD 7%) of all eyes, and was significantly more frequent in eyes with PEX (45 (11)%) than in eyes without PEX (24 (9)%, p < 0.03). Eyes with diabetes mellitus (n = 32) showed a significantly lower frequency of secondary cataract (11 (11)%) than eyes without diabetes mellitus (39 (8)%, p < 0.01). The influences of sex, open angle glaucoma, type of cataract, surgeon, positioning of IOL, and phacoemulsification versus nuclear expression on secondary cataract did not reach statistical significance. CONCLUSION: The higher frequency of secondary cataract could be considered as another potential complication of cataract surgery in eyes with PEX.

Aged↗

PubMed1997

Physician behavioral response to a Medicare price reduction.

OBJECTIVE: To investigate at the individual practice level physician behavioral responses to the Medicare fee reductions mandated in the Omnibus Budget Reconciliation Act of 1989. Symmetric and nonsymmetric behavioral responses are modeled and investigated. DATA SOURCES: Volume index calculated from data in the Part B Medicare Annual Data (BMAD) Provider Files for 1989 and 1990. The pricing data are from the Procedure Files. STUDY DESIGN: A fixed-effects model in carrier and in specialty is employed. DATA COLLECTION: No direct data collection is required as BMAD files are used in the study. Price and volume variables are expressed as Fisher indexes of change. PRINCIPAL FINDINGS: The results show nonsymmetrical behavioral response because practices that did not face significant fee reductions do not exhibit behavioral change. By contrast, losers partially compensate for the fee reductions. For every dollar cut in their fees, physicians recoup approximately 40 cents by increasing volume. Loser behavioral responses vary by specialty. CONCLUSIONS: The presence of a volume response suggests that price control alone is not sufficient to cap rising healthcare costs. This indicates that additional or other tools must be considered if cost containment is to be attained.

Cost Control↗

PubMed1996

Physician volume response to price controls.

The need to contain escalating health care costs is one of the major challenges facing health care systems today. It is often argued that price control is an effective tool for reducing both the level and the rate of growth in health spending. However, experience suggests that these savings may be partially offset by volume increases. These are initiated by providers, particularly physicians, who attempt to provide more health care goods and services in order to recapture lost revenues. This phenomenon is called the behavioral offset or volume response. This paper examines the physician behavioral response to the fee reductions at the practice level using the data from the U.S. Medicare program in 1989 and 1990. This is the most recent data currently available at the practice level for the Medicare program at this writing. This period of time corresponds to the fee reductions mandated by the Omnibus Budget Reconciliation Act of 1989 (OBRA89). The results show that the volume of services whose fees were cut by OBRA89 increased by 3.7% for every 10% fee reduction. This means that, for every dollar cut in their fees, physicians would recoup 37 cents by increasing volume. The presence of a volume response suggests that price control alone is not sufficient to cap rising health care costs. This indicates that additional or other tools must be considered if cost containment is to be attained.

Budgets↗

PubMed1996

[Tyndallometry for follow-up of iodine-125 brachytherapy of uveal malignant melanomas. Report of 2 patients].

BACKGROUND: Previous studies that used the noninvasive laser flare-cell meter (LFCM) have demonstrated impairment of the blood-aqueous barriers in eyes with uveal melanoma. Herein we report the use of the LFCM in the follow-up of brachytherapy in 2 patients after radiation therapy with iodine 125 for choroidal melanoma. CASE REPORT: Two women (59-and 57-years-old) with choroidal melanoma who were treated with iodine 125-plaque, were followed-up for 24 and 36 months, respectively. Complete ophthalmological examination including tyndallometry and echography were performed regularly. Following radiation, patient 1 showed decreasing flare values, that returned to normal level one year after radiation (5.9 photon counts/ms). The decrease in flare values correlated with fundoscopic and ultrasonographic signs of tumor regression. After 14 months, flare values suddenly increased up to 15 photon counts/ms, and fluorescein angiography revealed signs of radiation retinopathy. In patient 2, flare values (18.0 photon counts/ms) did not decrease after radiation but showed further increase one year after radiation (39.0 photon counts/ms). Slitlamp biomicroscopy revealed segmental iris neovascularization from 6 to 9 hours, corresponding to the site of the previous plaque application. CONCLUSIONS: Measurement of aqueous flare with the LFCM appears to be a useful ancillary diagnostic method in following patients after radiation therapy for uveal melanoma. In eyes that show an increase of aqueous flare months or years after radiation therapy, recurrence of the tumor, radiation retinopathy and iris neovascularization should be excluded.

Blood-Aqueous Barrier↗

PubMed1995

An alternative technique for treatment of choledocholithiasis found at laparoscopic cholecystectomy.

OBJECTIVE: To introduce a new strategy for dealing with abnormal cholangiograms at laparoscopic cholecystectomy that makes postoperative cholangiograms possible and facilitates stone extraction by assuring access to the duct for a guide-wire-assisted endoscopic retrograde sphincterotomy. DESIGN: Retrospective review of a prospectively maintained database. PATIENTS: Twenty-four patients with abnormal cholangiograms had a percutaneously placed double-lumen catheter threaded through the cystic duct and advanced into the duodenum. RESULTS: Ten successful guide-wire-assisted endoscopic retrograde sphincterotomies were performed without complications. Eleven normal postoperative cholangiograms suggested spontaneous stone passage or false-positive intraoperative cholangiograms. There were three technical failures in the early part of the series. CONCLUSIONS: This strategy is a reasonable alternative to laparoscopic common bile duct exploration (1) when the cholangiogram is questionably positive, (2) when prolonged anesthesia (poor-risk patient) should be avoided, (3) when the equipment for laparoscopic common bile duct exploration is not available, and (4) when spontaneous stone passage seems likely. Postoperative endoscopic retrograde sphincterotomy with stone extraction is facilitated when it becomes necessary because a guide wire can be introduced through the catheter.

Adult↗

PubMed1995

Laparoscopic inguinal herniorrhaphy. Results of a multicenter trial.

OBJECTIVE: The purpose of this study was to determine if laparoscopic inguinal herniorrhaphy represents a viable alternative to the conventional repair and to assess whether a prospective randomized controlled trial comparing both procedures is warranted. METHODS: Three types of laparoscopic inguinal herniorrhaphies (transabdominal preperitoneal [TAPP], intraperitoneal onlay mesh [IPOM], and totally extraperitoneal [EXTRA]) were studied in a phase II design. Twenty-one investigators from 19 institutions participated. Approval from the local human research committee was required at each institution before patients could be enrolled. RESULTS: There were 686 patients with 869 hernias; 366 (42.1%) were direct, 414 (47.6%) were indirect, 22 (2.5%) were femoral, and 67 (7.7%) were combination hernias. The TAPP procedure was used for 562 hernias, the IPOM was used for 217 hernias, and the EXTRA was used for 87 hernias. Sixty-one patients had additional abdominal procedures performed at the time of laparoscopy without any adverse affects on their herniorrhaphies. The overall recurrence rate was 4.5%, with a minimum follow-up of 15 months. Complications were divided into the following three groups: 1) those related to laparoscopy, 2) those related to the patient, and 3) those related to the herniorrhaphy. Complications related to the laparoscopy occurred in 5.4% of patients; bleeding or abdominal wall hematomas occurred 31 times, (two patients required transfusion); one patient had bowel perforation, which was sutured laparoscopically; a bladder injury required laparotomy for management. Patient complications occurred in 6.7%. The majority involved the urinary tract (5.8%). Two patients required secondary abdominal procedures for adhesions, one for pain in the right lower quadrant and the other for adhesive small bowel obstruction. Postoperative myocardial infarction on day 5 resulted in the only operative mortality, for a rate of 0.1%. Complications related to the herniorrhaphy itself occurred in 17.1%. Most of these were minor, consisting of transient groin pain (3.5%), seroma (3.5%), transient leg pain (3.3%), hematoma (1.5%), or transient cord or testicular problems (0.9%). The incidence of leg pain decreased dramatically as surgeons became more familiar with the anatomy of the nerve supply to the groin when viewed laparoscopically. Ninety-three percent of patients were discharged within 24 hours of their operations. CONCLUSIONS: Laparoscopic inguinal herniorrhaphy is an effective method to correct an inguinal hernia. It can be offered safely to patients undergoing other abdominal procedures. The TAPP, IPOM, and EXTRA procedures appear to be equally effective. A controlled randomized trial is needed to compare this procedure with conventional inguinal herniorrhaphy.

Adolescent↗

PubMed1995

The blood-aqueous barrier in eyes with pseudoexfoliation syndrome.

UNLABELLED: Eyes with pseudoexfoliation syndrome (PEX) frequently show clinical signs of impairment of the blood-aqueous barrier. Herein we give an overview of recent studies that analyzed the blood-aqueous barrier in eyes with PEX. METHODS: The authors review and summarize recent studies including quantification of aqueous flare in eyes with PEX using the laser flare cell meter (LFCM; Kowa FC-1000) in comparison with normal eyes and eyes with primary open-angle glaucoma (POAG), quantification of aqueous flare in eyes with PEX with and without secondary open-angle glaucoma (SOAG), and quantitative biochemical determination of total aqueous protein concentration in PEX eyes. In addition, studies of noninvasive quantification of the blood-aqueous barrier breakdown following trabeculectomy and following phacoemulsification with intraocular lens implantation in eyes with and without PEX are reviewed. RESULTS: In eyes with manifest PEX, both aqueous flare and aqueous protein concentration were significantly increased in comparison with normal control eyes and eyes with POAG. Flare values in PEX eyes with SOAG were not significantly different from flare values in PEX eyes without SOAG. Following trabeculectomy as well as following cataract surgery, breakdown of the blood-aqueous barrier as determined by quantification of aqueous flare was significantly higher in eyes with PEX than in eyes without PEX. CONCLUSIONS: Impairment of the blood-aqueous barrier with increase in aqueous protein concentration is a feature of PEX and may be quantified both by flare measurement and by biochemical protein determination. The extensive blood-aqueous barrier breakdown in eyes with PEX following intraocular surgery is an important risk factor for early or late postoperative complications. The alterations of the blood-aqueous barrier should be considered in the medical and surgical treatment of eyes with PEX.

Aged↗

PubMed1995

Aqueous flare and retinal capillary changes in eyes with diabetic retinopathy.

We examined 112 eyes of 112 adult-onset diabetic patients by fundus fluorescein angiography and with the laser flare cell meter (LFCM) in order to evaluate the possible correlation between retinal capillary changes and aqueous flare. Diabetic eyes were divided into the following groups: minor background diabetic retinopathy (MDR), nonproliferative diabetic retinopathy with predominant capillary occlusion (ONP), nonproliferative diabetic retinopathy with predominant capillary dilation and exudation (ENP) and proliferative diabetic retinopathy (PDR). 108 age-matched eyes of 108 normal subjects were used as control group. Flare values (photon counts/ms) of all diabetic groups (MDR 9.01 +/- 0.79, ONP 13.66 +/- 3.22, ENP 16.43 +/- 5.55, PDR 18.57 +/- 6.99) were significantly higher than in the normal control group (4.28 +/- 1.14, p < 0.0001). Significant differences were found between ONP and ENP (p = 0.008) and between ONP and PDR (p = 0.0001) but not between ENP and PDR (p = 0.4). Our results indicate that there is a correlation between aqueous flare and the type of angiographic retinal capillary changes with higher flare values in eyes with retinal capillary dilatation and exudation. Measurements with LFCM may be useful to quantify the extent and severity of capillary alterations in diabetic eyes.

Adult↗

PubMed1994

Quantitative assessment of the blood-aqueous barrier in human eyes with malignant or benign uveal tumors.

We assessed alterations of the blood-aqueous barrier in 43 eyes with malignant melanoma (31 choroidal and 12 ciliary body), 40 eyes with benign uveal tumors, and 199-age matched normal control eyes. Aqueous flare was quantified with the laser flare-cell meter and correlated with clinical and histopathologic findings. Aqueous flare (photon counts/ms) was significantly higher in melanoma eyes (20.91 +/- 12.40) than in eyes with benign tumors (4.26 +/- 1.55) (P < .0001) and normal control eyes (3.99 +/- 1.14) (P < .0001). In melanoma eyes, clinical and histologic findings associated with significantly increased aqueous flare values were as follows: tumor height, serous retinal detachment, tumor necrosis, lymphocytic tumor infiltration, and tumor hemorrhage. Development and growth of uveal melanomas are accompanied by marked alterations of the blood-aqueous barrier. The noninvasive laser flare-cell meter may give useful additional information about malignant and benign uveal tumors.

Aqueous Humor↗

PubMed1994

Aqueous flare following penetrating keratoplasty and in corneal graft rejection.

OBJECTIVE: Corneal allograft rejection is a major complication of penetrating keratoplasty (PK). We used the laser flare-cell meter that allows, for the first time, non-invasive quantification of aqueous flare in vivo to analyze alterations of the blood-aqueous barrier following uncomplicated PK and in acute corneal graft rejection. PATIENTS AND METHODS: Examination with the laser flare-cell meter was performed in 67 eyes of 62 patients (mean +/- SD age, 46.2 +/- 15.1 years) 12.8 +/- 13.2 months (range, 5 days to 60 months) after uncomplicated PK, in 82 normal control eyes of 82 age-and gender-matched patients (mean age, 49.0 +/- 17.1 years) and in 10 eyes of 10 patients (mean age, 51.6 +/- 15.1 years) with acute diffuse endothelial corneal graft rejection in nonherpetic eyes 15.1 +/- 12.9 months after PK. RESULTS: Compared with the normal unoperated control group (4.43 +/- 1.13 photon counts/ms), aqueous flare was significantly increased during the first 2 weeks following uncomplicated PK (14.73 +/- 8.30 photon counts/ms; P < .0001) but returned to normal levels more than 6 weeks after surgery (4.48 +/- 1.55 photon counts/ms; P > .1). In acute corneal graft rejection, aqueous flare values (17.10 +/- 6.05 photon counts/ms) increased to significantly higher levels than in eyes following uncomplicated PK and in the normal control group (P < .0001), but decreased significantly 9.5 +/- 3.3 days after treatment with systemic and topical corticosteroids (5.78 +/- 2.16; P < .0005). CONCLUSIONS: Application of the laser flare-cell meter appears promising for following up patients after PK and for detecting early corneal allograft rejection.

Acute Disease↗

PubMed1994

[Tyndallometry in monitoring therapy of sympathetic ophthalmia].

BACKGROUND: The Laser Flare-Cell Meter allows noninvasive quantitative measurement of aqueous flare in human eyes. In this study we analysed changes of aqueous flare in eyes with sympathetic ophthalmia under immunosuppressive treatment. PATIENTS AND METHOD: Two men (54- and 59-year-old) with sympathetic ophthalmia (histological examination of the enucleated eyes confirmed the clinical diagnosis) were examined regularly with the Laser Flare-Cell Meter (Kowa). According to the flare values the dose of immunosuppressive treatment with cyclosporin A and prednisolone was gradually titrated. RESULTS: Under immunosuppressive treatment flare values of patient 1 normalized within 21 months. The dose of immunosuppressive treatment was carefully reduced according to flare values. Patient 2 showed very high flare values before treatment, which decreased to flare values of 20 flare counts/ms within 5 months of treatment with cyclosporin A and prednisolone. Both patients stopped immunosuppressive treatment because of systemic side-effects. Thereafter flare values increased acutely and a recurrence of sympathetic ophthalmia was observed in both patients. Under renewed immunosuppressive treatment aqueous flare values decreased again. CONCLUSION: Measurement of aqueous flare with the LFCM appears to be an effective tool for follow-up examinations, and especially for titrating of immunosuppressive treatment in eyes with manifest sympathetic ophthalmia.

Cyclosporine↗

PubMed1994

[Use of a new anomaloscope test in diagnosis of glaucoma].

BACKGROUND: The Color Vision Meter 712 (CVM) is a new automatic computerized anomaloscope relying on both the Rayleigh and the Moreland equation. In the present study the diagnostic value of Color Vision Meter was examined in glaucoma for the first time and was compared with the Farnsworth 100 hue test. PATIENTS AND METHODS: 33 normals, 15 patients with ocular hypertension (OHT) and a heterogenic group of 31 glaucoma patients were tested with the Nagel anomaloscope, the Color Vision Meter 712 and the Farnsworth 100 hue test. The following determinations were made in all subjects: 1. Anomalous quotient of the Rayleigh equation of the Nagel anomaloscope and of the Color Vision Meter, 2. Mean tritan score of 100 hue test, 3. The matching range, mid matching point, and anomalous quotient of the Moreland equation with the Color Vision Meter. RESULTS: While in the OHT group only the matching range of the Moreland equation was enlarged, all three variables (matching range, mid matching point and anomalous quotient) of the Moreland equation were significantly changed in the glaucoma group. The mean tritan score of the 100 hue test showed in the OHT group only a slight difference compared to normals, and in the glaucoma group a low significance and a low sensitivity. The matching range of the Moreland equation seems to be most useful with a sensitivity of 87.1% and a specificity of 93.6%. CONCLUSION: Our results show that the new anomaloscope Color Vision Meter 712 should be considered as a quick screening test for the examination of blue-color vision disturbances in glaucoma because of its higher sensitivity, its easier use for examiner and patients, and its shortened examination time (5 min per equation).

Adult↗

PubMed1994

[Quantification of disorders of the blood-aqueous humor barrier in retinitis pigmentosa--initial results].

BACKGROUND: Clinical findings in patients with retinitis pigmentosa (RP) frequently include cystoid macular edema (CME) and vitreous pigment dusting (VPD) indicating alterations of the blood-ocular barriers. It was the aim of this study to determine whether alterations of the blood-aqueous barrier (BAB) are present in RP. PATIENTS AND METHODS: Aqueous flare was quantitatively determined in 56 eyes of 29 patients (mean age 36.4 +/- 11.2 years) with RP using the noninvasive laser flare-cell photometer (Kowa FC-1000, Tokyo, Japan). All RP patients had common forms of RP with markedly reduced or nondetectable ERG. The presence of CME and VPD was determined semiquantitatively by biomicroscopy. Fifty-eight eyes of 58 normal controls (mean age 38.2 +/- 8.5 y.) were also examined. RESULTS: Aqueous-flare values were significantly higher in RP eyes (mean 9.65 +/- 3.24 photon counts/ms, range 4.0-18.1) than in the normal control eyes (mean 3.89 +/- 1.05, range 1.9-6.0, p < 0.0001, Mann-Whytney test). Forty-eight of the 56 RP eyes (86%) showed increased flare values (> 6.0 photon counts/ms). RP eyes with moderate to marked CME (n = 11) had significantly higher flare values (mean 14.66 +/- 1.92) than RP eyes without or with only questionable CME (8.52 +/- 2.18, p < 0.0001), and RP eyes with moderate to marked VPD (n = 17) had significantly higher (12.05 +/- 2.84) flare values than RP eyes without or with only minimal VPD (8.74 +/- 2.22, p < 0.0005). CONCLUSIONS: Our findings show that the majority of patients with RP have alterations of the BAB with consecutively increased aqueous protein concentrations. The impairment of the BAB appears to be associated with CME and VPD. Measurement of aqueous flare in RP allows quantification of the impairment of the BAB and may be helpful in the future in choosing and monitoring patients with RP and CMP for possible antiinflammatory or antiedematous therapeutic measures.

Adult↗

PubMed1994

[Tyndallometry with the laser flare cell meter and biochemical protein determination in the aqueous humor of eyes with pseudoexfoliation syndrome].

UNLABELLED: Slit-lamp examination and flare measurement in eyes with pseudoexfoliation (PSX) syndrome frequently reveal signs of impairment of the blood-aqueous barrier. We studied both aqueous flare and aqueous protein concentration in PSX eyes to verify and quantify these alterations. PATIENTS: Aqueous flare was measured using the Laser Flare-Cell Meter Kowa FC-1000 in 158 normal control eyes (age 56.0 +/- 12.0 years), in 60 PSX eyes (age 72.5 +/- 9.4 years), and in 84 eyes with primary chronic open-angle glaucoma (PCOAG) (age 56.3 +/- 12.4 years). Total aqueous protein concentration was determined biochemically in 12 "normal" control eyes with senile cataracts (age 57.6 +/- 20.4 years), in 27 PSX eyes (age 72.6 +/- 9.1 years), and in 25 PCOAG eyes (age 63.3 +/- 13.5 years). After the primary aqueous humor was aspirated during cataract extraction or trabeculectomy, a modified BCA-Peirce method was employed. RESULTS: In PSX eyes, both aqueous flare (12.3 +/- 8.2 photon counts/ms) and aqueous protein concentration (0.42 +/- 0.16 mg/ml total protein) were significantly increased in comparison with normal control eyes (4.3 +/- 1.1 photon counts/ms and 0.22 +/- 0.08 mg/ml) and with PCOAG eyes (4.7 +/- 1.6 photon counts/ms and 0.26 +/- 0.09 mg/ml) (P < 0.0001). Differences between normal control eyes and PCOAG eyes were not significant (P > 0.05). There was a high correlation between aqueous flare measurements and aqueous protein concentration in eyes with PSX (y = 0.27x + 0.29, r = 0.65, P = 0.0006, n = 24). CONCLUSIONS: Our results indicate that impairment of the blood-aqueous barrier with an increase in aqueous protein concentration is a feature of PSX and may be quantified both by flare measurement and biochemical protein determination. These alterations should be considered in the pharmacological and surgical treatment of PSX eyes.

Adult↗

PubMed1994

Aqueous flare in eyes with age-related macular degeneration.

It is unknown whether aqueous flare is increased in eyes with prominent fundus lesions other than choroidal malignant melanoma. Therefore, we studied the aqueous flare in eyes with age-related macular degeneration (ARMD) using the laser flare-cell meter. Forty-three eyes of 27 patients with ARMD (age 67.0 +/- 14.0 years, range 43-81 years), and 41 healthy eyes of 41 randomly selected age- and gender-matched control patients (age 68.9 +/- 9.8 years, range 43-89 years) were examined. The macular degeneration was diagnosed and classified using fluorescein angiograms. Flare values in eyes with ARMD were 0.28 +/- 0.18 mg/ml, being significant in comparison with the control (0.12 +/- 0.05 mg/ml). The differences among the subgroups of ARMD were not statistically significant (P > 0.5): macular drusenosis (0.21 +/- 0.05 mg/ml, n = 6), subretinal neovascularization without marked subretinal hemorrhage (0.27 +/- 0.15 mg/ml, n = 19), subretinal neovascularization with marked subretinal hemorrhage (0.29 +/- 0.24 mg/ml, n = 7), and disciform scar (0.31 +/- 0.24 mg/ml, n = 9).

Adult↗

PubMed1994

[Tyndallometry with the laser flare cell meter in intraocular inflammation].

The laser flare-cell meter (LFCM) allows noninvasive, quantitative measurement of aqueous flare in human eyes. In this study we analysed changes in aqueous flare in eyes with various forms of intraocular inflammations. PATIENTS. We examined 100 eyes of 100 patients aged (mean +/- SD) 40.2 +/- 19.8 years with acute and chronic intraocular inflammations. The inflammatory diseases were classified according to morphological criteria. In addition, 163 normal eyes of 163 subjects (mean age 44.8 +/- 17.9 years) were evaluated. The eyes were examined by three examiners using the LFCM (Kowa, FC-1000) after pupillary dilatation with mydriatics. The instrument was calibrated with standardized concentrations of human albumin concentrations, and flare values were transformed into human albumin concentration equivalents. For statistical analysis, the non-parametric Wilcoxon-Mann-Whitney test was used. RESULTS. Flare values (mean +/- SD) in the eyes with intraocular inflammations were 4.38 +/- 11.82 mg/ml human albumin equivalents and were significantly higher than in the group of normal eyes (0.11 +/- 0.06 mg/ml, P < 0.0001). In addition, flare values differed in the various inflammation groups, with human albumin concentration equivalents decreasing in the following order: acute iridocyclitis (n = 27, 10.81 +/- 21.12), chronic iridocyclitis (n = 19, 5.19 +/- 6.12), necrotizing retinitis (n = 6, 1.92 +/- 1.11), acute retinochoroiditis (n = 9, 1.46 +/- 2.35), retinal vasculitis (n = 24, 1.03 +/- 0.90), chorioretinitis (n = 5, 0.98 +/- 0.71), Fuchs' uveitis (n = 10, 0.52 +/- 0.25). CONCLUSION. Measurement of aqueous flare with the LFCM is a noninvasive examination that yields objective, quantitative and reproducible results and therefore has advantages over slit-lamp assessment. It gives valuable information about the integrity or impairment of the blood-aqueous barrier. Its possible clinical applications include follow-up examinations and "monitoring" of therapeutic regimens in uveitis.

Adolescent↗