Iris Changes Research Articles

Ultrasound biomicroscopic quantitative analysis of light-dark changes associated with pupillary block

PURPOSE: To quantitatively analyze the changes in anterior chamber angle and iris configuration induced by varying illumination in patients with narrow angles and pupillary block. METHODS: Twenty-four eyes of 24 patients with pupillary block (mean age, 52.5 years) had ultrasound biomicroscopic images of the angle and iris structures obtained superiorly, nasally, inferiorly, and temporally. Images were performed in the light and the dark. We measured the angle opening distance, iris thickness, iris chord length, iris-lens touch, and iris curvature. RESULTS: Changes in iris and angle configuration occurred within a few seconds of a change in lighting. The mean dark measurements were statistically significantly less than the mean light measurements for angle opening distance (96 ± 18 vs 185 ± 26 μm, P = .0001), iris chord length (2,505 ± 61 vs 3,001 ± 69 μm, P = .0001), and iris-lens touch (350 ± 20 vs 693 ± 35 μm, P = .0001). The mean dark measurements were statistically significantly greater than the mean light measurements for iris thickness at 500 μm from the scleral spur (367 ± 10 vs 307 ± 25 μm, P = .0001), and 1,500 μm from the scleral spur (404 ± 14 vs 347 ± 12 μm, P = .0001). Iris curvature in all four quadrants was statistically significantly greater in the dark than the light. CONCLUSIONS: This study quantitatively confirms that angle narrowing in the dark in eyes with pupillary block is associated with iris shortening, increased iris thickness, and increased iris convexity. Iris-lens touch is relatively small in pupillary block and decreases with dilation. Angle narrowing with dilation is not related to increased iris-lens touch and occurs promptly without requiring time for aqueous pressure buildup behind the iris.

Effects of topical carteolol and timolol on tissue circulation in the iris and choroid

Purpose. To evaluate the effects of topical carteolol or timolol on tissue circulation in the iris and posterior choroid. Methods. After a topical instillation of 20 µl of 2% carteolol, 0.5% timolol, or physiological saline (for control) into one eye, and physiological saline into the other eye of pento-barbital-anesthetized Dutch pigmented rabbits, normalized blur value; a quantitative index of tissue blood velocity in the iris (NB iris) and posterior choroid (NB cho) was obtained using the laser-speckle method. Intraocular pressure (IOP), blood pressure and pulse rate were serially monitored for 2 hours after instillation. Using separate groups of rabbits, NB iris and IOP were measured before and after 20-day twice-daily unilateral treatment of carteolol or timolol. Results. After a single instillation of carteolol, NB iris was significantly greater only in the treated eyes than control eyes (P = 0.0050, repeated measures two-way ANOVA), while NB cho showed no significant change. IOP in the treated eyes significantly reduced (P = 0.0005). Bilateral reductions of tissue vascular resistance in the iris were found after carteolol instillation (P = 0.0183 ~ 0.0322). After timolol instillation, serial changes in NB iris and NB cho in the treated eyes were significantly different from those in control eyes (P = 0.0129, 0.0031), while there were no significant differences at any of time points (Mann-Whitney test); IOP in both eyes was significantly reduced (P = 0.0096 ~ 0.0005); tissue vascular resistance in the iris and posterior choroid showed no significant changes. After 20-day treatment, NB iris in the both eyes of carteolol-treated rabbits significantly increased from the baseline (P = 0.0280, 0.0425, Wilcoxon signed rank test) and NB iris in timolol-treated eyes significantly decreased (P = 0.0280). Conclusions. A single instillation of topical carteolol significantly increased the iris tissue blood velocity in the treated eye and reduced the tissue vascular resistance in both eyes. Topical timolol tended to decrease tissue blood velocity in the iris and choroid of the treated eye, but showed no significant effects on tissue vascular resistance in the both tissues.

Ocular manifestations in multiple endocrine neoplasia type 2b

PURPOSE: To describe the clinical and laboratory findings in a patient with multiple endocrine neoplasia type 2b. METHOD: Case report. An 8-year-old boy underwent ophthalmic examination, genetic evaluation, total thyroidectomy, and biopsy of a tongue nodule. RESULTS: Ocular features, including previously unreported iris changes, and their probable origin are discussed. Genetic testing detected the point mutation at codon 918 within the RET proto-oncogene on chromosome 10, characteristic of multiple endocrine neoplasia type 2b. Histologic analysis of excised thyroid tissue disclosed medullary carcinoma. A tongue nodule proved to be neuromatous. CONCLUSION: Ophthalmologists can play an important role in the recognition of multiple endocrine neoplasia type 2b, a potentially lethal condition.

Effect of Topical Carteolol on Iridial Circulation in Pigmented Rabbit Eyes

The effect of a single instillation of topical carteolol on iridial tissue circulation of pigmented rabbits was studied. The blood flow rate and a quantitative index of tissue blood velocity (NB iris) were measured simultaneously, using the microsphere technique and the laser speckle method, before and 2 hours after the instillation of 20 microliters of 2% carteolol or the vehicle. Consecutive changes of intraocular pressure and NB iris were also studied at 30-minute intervals for 2.5 hours after a single instillation of 2% carteolol in one eye and the vehicle in the contralateral eye. To provide a control, intraocular pressure and NB iris were measured according to the same schedule after the vehicle instillation in both eyes. Two hours after carteolol instillation, iridial blood flow rate and NB iris significantly increased to 127 ± 8% and 122 ± 9% (mean ± SEM, n = 8) of the baseline. Unilateral instillation of carteolol significantly reduced intraocular pressure by about 9 mm Hg in both the carteolol- and vehicle-treated eyes ( P < 0.001, analysis of variance); and NB iris was significantly increased by about 20% in both eyes ( P < 0.001, analysis of variance), compared with control eyes.

Pediatric Cataract Management with Variations in Surgical Technique and Aphakic Optical Correction

The purpose of the study was to compare the results of three techniques of cataract surgery in children. Two methods included intraocular lens (IOL) implantation and one used contact lens correction of aphakia. Nonrandomized clinical trial. Seventy-seven eyes of 50 children between the ages of 2 1/2 and 16 years who had cataract surgery for the treatment of uncomplicated cataract. Thirty-one eyes underwent a "conventional" style of implantation, and a "phaco-style" of surgery was used in 24 eyes. A contact lens was used as the primary means of aphakic correction in 22 eyes. The visual results and complications of each type of surgery were compared. Corrected visual acuities did not differ significantly between the three groups 6 months after surgery. The incidence and type of complications were significantly different. Better lens centration, less long-term iris changes, or wound-related problems were observed with "phaco-style" modification of the technique of IOL insertion. Pediatric IOL insertion eliminated the need for contact lens wear and did not lead to a significantly different corrected visual acuity 6 months after surgery compared with lensectomy with contact lens correction. Adoption of some of the techniques of modern small-incision cataract surgery for pediatric IOL procedures produces a significant reduction in postoperative anterior segment complications compared with a standard limbal approach. Such modifications allow pediatric IOL insertion to be a safe alternative for the correction of pediatric aphakia.

Cornea and Iris Changes in Congenital Ectropion Uvea After Trabeculotomy

This article details a previously undescribed complication of trabeculotomy occurring in a patient with congenital ectropion uvea and discusses its possible association with an anterior chamber membrane. A 6-year-old boy with congenital ectropion uvea underwent trabeculotomy. After the trabeculotome was swept into the anterior chamber, multiple ovoid and round endothelial and posterior stromal opacities developed in the cornea, and new areas of iris surface irregularities appeared. This is the first reported case of corneal endothelial and iris changes occurring in a patient with congenital ectropion uvea after trabeculotomy without direct endothelial or iris contact from the trabeculotome. The exact cause of these changes is unknown.

Iridoschisis: high frequency ultrasound imaging. Evidence for a genetic defect?

To elucidate changes in the anatomy of the anterior chamber associated with iridoschisis, a rare form of iris atrophy, and their potential contribution to angle closure glaucoma. Both eyes of a 71-year-old woman with bilateral iridoschisis and fibrous dysplasia and her asymptomatic 50-year-old daughter were scanned with a very high frequency (50 MHz) ultrasound system. The symptomatic patient exhibited diffuse changes in the iris stoma with an intact posterior iris pigmented layer in both eyes. These changes were clinically compatible with the lack of iris transillumination defects. Additionally, iris bowing with a resultant narrowing of the angle occurred. The asymptomatic daughter showed discrete, but less severe iris stromal changes. This is the first detailed study of high frequency ultrasonic imaging of the iris in iridoschisis. The observed structural changes suggest angle narrowing by forward bowing of the anterior iris stroma may be a mechanism of IOP elevation in this condition. The ultrasonic detection of iris changes in the asymptomatic daughter of the symptomatic patient and the association of iridoschisis with fibrous dysplasia suggest a possible genetic component in the pathogenesis of this condition.

Ultrastructural Age-Related Changes on the Posterior Iris Surface

To verify the presence of age-related changes in the human iris and to determine whether such changes could be related to the pathogenesis of the exfoliation syndrome. Ultrastructural examination of the posterior surface of the normal iris in 9 enucleated eyes. Eyes of persons aged 1 day, 3 months, and 3, 9, 27, 52, 59, 59, and 65 years. The presence of aging changes in the iris. Aging changes included duplication of the basal lamina of posterior iris pigment epithelial cells, formation of atrophic invaginations in the posterior cell membranes containing interlacing basal lamina, formation (or deposition) of microfibrils 11 to 13 nm in diameter, with a banding periodicity of 12 to 16 nm, deposition of electron-dense material in relation to the basal lamina and/or microfibrils, and the presence of some fine granular material overlying the basal lamina. These changes have been consistently described before in association with exfoliation material, which suggests the possibility that exfoliation is an eventual aging process.

Neurofibromatosis type 1 in children

To document ophthalmic and general characteristics of Neurofibromatosis Type 1 (NF1) in children; and to characterize the iris changes of NF1 including their variability and reliability.One hundred and ninety-six patients with NF1 were evaluated for general characteristics; 156 patients underwent prospective eye evaluations; and 151 NF1 patients and controls had iris photography in accordance with a protocol. Masked evaluation of photographs compared to a known diagnosis, and interobserver reliability tests were performed.Incidence of iris changes consistent with NF1 (Lisch nodules, plus) by age group; spectrum of iris changes found; correlation of iris findings to known diagnosis and Kappa coefficients for interobserver reliability.Iris changes were common in children over age 5, and increased with age; masked evaluation of photographs compared to a known diagnosis yielded fair to poor correlation (Kappa = -.02 to .50); interobserver reliability was poor (Kappa = -.02 to .24, overall .174); iris changes found in NF1 are more diverse than classic descriptions of Lisch nodules, and including a broader spectrum probably increases the sensitivity and decreases the specificity of their diagnostic value.Iris changes as a diagnostic marker for NF1 may need rethinking; this study calls to question their reliability and validity.

Die komplexe Untersuchung der Iris im transformierten Licht bei Glaucoma simplex

Complex examination of the iris under light transformed by various methods - iridochromoscopy with iridochromophotography, transillumination in red light, and fluorescein angiography - was performed on 26 eyes of patients with simple glaucoma and 24 normal eyes of subjects aged between 42 and 76 years. All the methods employed revealed iris changes in 100% of the simple glaucoma cases. The differences found between the study group and the controls were significant (P = 0.01). A highly positive correlation was found between the results of iris fluorescein angiography and iridochromoscopy with iridochromophotography (r = 0.932; P = 0.0005), as well as between the results of iris fluorescein angiography and transillumination in red light (r = 0.921; P = 0.0005). Complex examination of the iris under transformed light showed the most typical changes in simple glaucoma to be exogenous pigmentation of the pupillary and ciliary regions, partial or complete destruction of the pupillary margin, and stromal atrophy affecting the pupil or the entire iris. Defects and thinning of the posterior iris pigment layer, iris vessel permeability disorders associated with hypoperfusion and microneovascularization in the lesser circle and the ciliary region were also found.

Treatment of acromegaly with long acting somatostatin analogue SMS 201-995.

Ten acromegalic patients were treated with the somatostatin analogue SMS 201-995 (SMS) for 3-38 weeks in various doses and by different administration routines (thrice daily or multiple sc injection). Plasma GH daily profiles, plasma IGF-I, urinary GH, serum TSH, IRI and fasting blood glucose (FBG) concentrations were measured before and during SMS treatment. Plasma GH rapidly decreased within one hour in all patients and was suppressed for at least 4 h after a 50 micrograms sc injection of SMS in 8 patients. Multiple injections of 300-600 micrograms/day SMS (25-50 micrograms X 12) suppressed GH throughout the day. Plasma IGF-I was completely normalized in 4 patients, and, in all but one of the others, decreased markedly. Urinary GH decreased within the first week of treatment in all patients and normalization was obtained in 3 patients. Shrinkage of the pituitary tumor, as determined by CT or MRI, was observed in 7 of 9 patients. Other clinical improvements, such as diminution or complete disappearance of swelling of soft tissues, excessive perspiration, and headache, were observed in 7 of 8 patients. Changes in serum TSH, IRI and FBG were seen in 3-4 patients, but without any apparent clinical problems. In conclusion, SMS is a useful clinical tool for treatment of acromegaly, and a multiple sc injection method seems to be preferable.

Iris atrophy with hypoperfusion and microneovascularisation.

A series of 17 patients with stromal atrophy, hypoperfusion, and microneovascularisation of the iris investigated in the Glaucoma Investigation and Research Unit are described, and their iris angiograms were compared with those of normal irides of patients in the same age group seen in general clinics. In all but one of the 17 cases this iris atrophy was associated with glaucoma or ocular hypertension, which appeared to be secondary to the iris changes. The condition was bilateral and presented a typical slit-lamp appearance, with subtle evidence of microneovascularisation. There was neither history nor clinical evidence of previous trauma, heterochromia, or intraocular inflammation. The commonest form of iris atrophy affected the inner third of the iris stroma in a patchy manner, often with sparing above. However, diffuse atrophy occurred in two cases, and there were two cases of 'senile tears' of the iris. Some accompanying atrophy of the pigment epithelium was usual but less prominent. The changes on fluorescein angiography of the iris included the late appearance of dye with a long arteriovenous circulation time, fewer arteries than normal with sectorial hypoperfusion, leakage of dye from the pupil margin and peripupillary neovascularisation, stromal tufts, and sometimes more complex stromal microneovascularisation. An expanded prominent lesser vascular circle was a common feature of the condition. The condition is bilateral and distinct from other forms of iris atrophy. In all cases the iris changes appeared to be secondary to the vascular hypoperfusion and were not consistently associated with evidence of gross vascular disease. All patients had grey (blue) irides, and this may be an aetiological factor. The condition appears common enough to form a significant group of glaucoma patients and to be a separate clinical entity.

Glucose turnover in insulinoma — a case report

To define glucose flux in a state of chronic endogenous insulin excess, a patient with an insulinoma was studied. Plasma glucose, insulin (IRI), glucagon (IRG) and glucose turnover ([3-3H]glucose infusion) were measured before and after insulinoma resection in the postabsorptive state (PA), during a glucose infusion adjusted to attain euglycemia (before insulinoma resection only) and following an intravenous glucagon bolus (1 mg). Before insulinoma resection, plasma glucose was 55 mg/dl, glucose production (Ra) and disappearance (Rd) were equal (1.6 mg/kg/min) and glucose clearance was elevated (2.8 ml/kg/min) in PA. When glycemia was raised with a glucose infusion to 77 mg/dl, Rd did not change; in contrast Ra dropped to zero. Plasma IRI and IRG concentrations were 0.7 ng/ml and 110 pg/ml respectively before glucose infusion and remained constant throughout. After resection of the insulinoma, glycemia in PA was 103 mg/dl, Ra and Rd were increased slightly to 1.9 mg/kg/min while the metabolic clearance of glucose was decreased by 25% (2.1 ml/kg/min). Glucagon stimulation pre- and postinsulinoma resection resulted in significant increases in glycemia and IRI. We conclude that hypoglycemia with insulinoma is a consequence of decreased glucose production and increased glucose clearance. Hepatic sensitivity to small increments in glycemia is markedly enhanced so as to fully suppress endogenous glucose production at euglycemic levels in the absence of any change in IRI and IRG. The mechanisms controlling hepatic Ra in insulinoma appear different from normal.

Glucoregulatory role of cortisol and epinephrine interactions studied in adrenalectomized dogs.

The importance of basal cortisol (H) and epinephrine (E) levels on glucoregulation, and the effects of E, given to simulate moderate to severe stress (5 times basal rate of infusion), were examined in seven conscious adrenalectomized dogs. Although plasma glucagon (IRG) increased by 47%, insulin (IRI) decreased by 36%, norepinephrine (NE) increased by 103%, and FFA decreased by 26%, glucose concentration and kinetics remained normal after adrenalectomy. A 4-h infusion of H reestablished basal cortisol levels and returned IRG to its basal preadrenalectomy level with no change in IRI, NE, and FFA levels. Glucose production and metabolic clearance decreased concomitantly by 20%, maintaining euglycemia. A 90-min infusion of basal E caused only a transient increase in IRG. The simultaneous infusion of H with E prevented this increase in IRG and returned IRI to preadrenalectomy levels in the absence of any change in NE or glucose. A subsequent infusion of five times basal E, alone, raised circulating E levels and caused a transient decrease in plasma NE, but no change in IRI. There was a similar hyperglycemic response, as seen previously in normal dogs. The simultaneous infusion of H and E prevented the decrease in NE, but did not change the IRI and FFA responses. There was an 80% greater plasma glucose response than seen during infusion of E alone. In conclusion, what E and H lack after adrenalectomy is compensated for by an increase in IRG and a decrease in IRI, and normal glucose concentrations and kinetics are maintained. It appeared that normoglucagonemia required basal H release, whereas normoinsulinemia required both basal H and E secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

IRI・CPR・IRGの動態よりみた肝性糖代謝異常について

To study abnormal carbohydrate metabolism accompanying liver diseases, we evaluated the changes in IRI, CRP and IRG following oral gllucose tolerance test, the results obtained were as follows.1) Liv er diseases were frequently accompanied by abnormal carbohydrate metabolism. Glucose tolerance was abnormal in 37.5% of acute hepatitis and in 86.9% of liver cirrhosis.2) Delayed hyper-responsiveness of IRI and CRP, and hyper-responsiveness as well as decreased inhibition of IRG were observed in many patients with liver disease. These findings were especially prominant in those with liver cirrhosis, suggesting increased functional activity of A and B cells. However, patients observed for 10 years showed hypo-responsiveoess of CRP and decreased IRG, indicating hypofunction of both A and B cell.3) Significantly positive correlation were found between IRG and each of ICG, albumin and E/T ratio in liver cirrhosis, these findings strongly suggest that dysfunction of the liver is involved in the development of hyperglucagonemia in those with liver cirrhosis.

Adreneric control of insulin release from isolated islet tissue in the rainbow trout, Salmo gairdneri R

Immunoreactive insulin levels (IRI) were measured by a homologous fish insulin radioimmunoassay. An in vitro pancreatic islet superfusion technique was employed to monitor the changes in IRI in the presence and absence of specific adrenergic agonists and antagonists. Exogenous adrenaline at low concentrations (10 −10 M) inhibited IRI release but evoked an IRI stimulation at high concentrations (10 −10 M). The stimulation of IRI by adrenaline is thought to involve β-adrenoceptors located postsynaptically on the β-cell membrane as the effect of adrenaline was mimicked by the β-agonist, isoproterenol, and abolished by the β-antagonist propranolol. Phentolamine (an α-antagonist) potentiated the adrenergic stimulation of IRI, whereas yohimbine (an α 2-antagonist) was without effect. Phenylephrine ( α 1-adrenoceptor agonist) IRI release suggesting the presence of α 2-inhibitory adrenoceptors which exert a modulatory influence on adrenaline-stimulated insulin release.

Reduction of fluoroscopic exposure for the air-contrast barium enema.

In a fluoroscopic imaging system, image quality and patient dose are both affected by the optical system linking the image intensifier with the video camera. The effect on patient exposure of increasing the optical iris aperture size over that required for other procedures performed on the same imaging system was investigated for the air-contrast barium enema examination. Using a large-area transmission ionisation chamber to monitor the Roentgen-area-product of entrance exposure, a decrease in fluoroscopic radiation of greater than 50% was clinically documented for a fluoroscopic system utilising kVp and mA variable automatic brightness control. For this iris change, the video image was of acceptable quality for positioning and monitoring the patient, and no deleterious effect was detected in the conduct of the air-contrast exam. The availability of a variable-sized operator-selectable iris diaphragm would permit this dose-reduction approach to be extended to other fluoroscopic procedures.

Analysis of insulin secretion based on changes in plasma insulin and C-peptide in man.

In order to clarify the mechanism of insulin secretion, responses of insulin (IRI) and C-peptide (CPR) in plasma to various stimuli were investigated in normal subjects and patients with diabetes mellitus, liver cirrhosis, chronic nephritis or insulinoma. The response of plasma IRI and CPR to oral glucose load was less marked in the mild and moderate diabetes groups than in the normal controls. Neither IRI nor CPR in the severe diabetes group responded to oral glucose. The patients with liver cirrhosis revealed an exaggerated and delayed response of IRI and CPR, and a lowered CPR/IRI ratio, indicating a remarkable response of IRI to glucose. In contrast, the patients with chronic nephritis showed a prominent rise of CPR alone. In the insulinoma patients, both plasma IRI and CPR increased after glucose load. In the response to glucose, there was approximately 30-min lag time between the peaks of IRI and CPR in the normal controls and the patients with various diseases. Following arginine infusion, plasma IRI and CPR increased in the normal subjects and the patients with moderate diabetes. In the normal subjects, plasma IRI reached a peak at 6 min and 3 min in response to tolbutamide and glucagon, respectively, which elicit an abrupt and sharp rise of insulin from B-cells. However, diabetic patients showed a minimal change in plasma IRI and CPR, whereas there was an exaggerated response of plasma IRI and CPR in insulinoma patients. In analysis of responses of plasma IRI and CPR to tolbutamide or glucagon, there was a lag time longer than 10 min in the normal subjects. The present study confirms the concurrent release of C-peptide from the B-cells in the secretion of insulin. In addition, it was suggested that insulin and C-peptide are mainly handled in the liver and the kidney, respectively. Furthermore, a longer lag time between the peaks of IRI and CPR in response to tolbutamide or glucagon did not necessarily indicate a simultaneous release of insulin and C-peptide from the B-cell, but a delayed release of the latter.

Iris and Fundus Pigmentary Changes in Tuberous Sclerosis

Iris and Fundus Pigmentary Changes in Tuberous Sclerosis

Effects of intravenous fat emulsion administration on exocrine and endocrine pancreatic function.

A study was made of alterations in exocrine and endocrine function of the pancreas following infusion of a 10% fat emulsion preparation (Intralipid) into 5 patients after pancreaticoduodenectomy and in 5 dogs with a chronic pancreatic fistula. Pancreatic exocrine secretion was significantly increased by 18.3% in the volume, 27.5% in the output of bicarbonate in humans and 8.9% in the volume, 26.1% in the output of amylase, 7.6% in the output of bicarbonate in dogs, by intravenous administration of the fat emulsion. The administration of the fat emulsion was followed by slight to minimal changes in blood sugar, amylase and IRI. The blood IRG level was significantly elevated but showed small fluctuations. The increase in pancreatic exocrine secretion induced by the fat emulsion was considered not to be mediated by intrinsic hormones but rather to be due to other humoral mechanisms.