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At least 379 records · Page 21Linked to original sources

The effect of intracameral adrenaline infusion on pupil size, pulse rate, and blood pressure during phacoemulsification.

Pupillary constriction during phacoemulsification (phaco) and irrigation/aspiration (I/A) is found to be the major cause of iris damage, incomplete cortex removal, posterior capsule rupture, vitreous loss and even posterior lens material dislocation. Cataract surgery is performed more easily if mydriasis can be maintained. Irrigation fluid containing adrenaline is thought to be of benefit in this respect. We designed a prospective study assessing the efficacy and safety of using perioperative adrenaline during phacoemulsification, as an adjunct to preoperative topical mydriatics. Forty-two cases were randomized to receive intraocular irrigation fluid with or without 1:1,000,000 adrenaline, as a study or control group. Diameter of the pupil, pulse rate, systolic and diastolic pressure before-phaco, after-phaco-before-I/A and after-I/A were measured. All of the operations were performed by the same surgeon with the same technique. The pupil size after-phaco-before-I/A was 8.00 mm in the study group and 5.96 mm in the control group. The mydriasis maintained during phacoemulsification was significantly greater in the study group, p < 0.00001. The pupil size after-I/A was 8.03 mm in the study group, and 5.54 mm in the control group. The mydriasis maintained during I/A was significantly greater in the study group, p < 0.00001. Pulse rate and blood pressure in patients of the study group, even those with hypertension, showed no significant fluctuation during the surgery. We concluded that intraocular irrigation with 1:1,000,000 adrenaline was a safe and effective way of maintaining mydriasis during cataract surgery.

Blood Pressure↗

Experimental retinal detachment. I. Effect of subretinal fluid composition on reabsorption rate and intraocular pressure.

Retinal detachments (RDs) were produced in rhesus monkeys by a 1-ml subretinal fluid injection combined with simultaneous vitreous aspiration. Four groups of five eyes each were studied according to type of fluid injected: autologous serum, glutathione-bicarbonate Ringer's solution (GBR), silicone oil, or no fluid (sham operation). Retinal detachments created with GBR reattached within two to seven days; RDs created with serum decreased in volume at a rate ten times slower than that of eyes detached with GBR; RDs created with silicone oil and sham-operated eyes remained unchanged during three weeks of observation. Active transport of fluid out of the subretinal space best explains these findings. Transient hypotony developed in all eyes in association with postoperative inflammation and reduced aqueous humor formation. Eyes with persistent detachment (serum and silicone oil) retained mild hypotony three weeks after operation, suggesting a pressure-lowering effect of the detachment itself.

Animals↗

Intraocular adrenaline maintains mydriasis during cataract surgery.

Cataract surgery is performed more easily if mydriasis can be maintained until the intraocular lens has been inserted. Intraocular irrigation with adrenaline is thought to be of benefit in this respect, and is used by some surgeons but not others. This prospective double blind controlled trial assessed the efficacy and safety of using perioperative adrenaline during extracapsular cataract surgery, as an adjunct to preoperative topical mydriatics. Seventy patients were randomised to receive intraocular irrigation fluid with or without 1:1,000,000 adrenaline. The adrenaline entering the eye through the anterior capsulotomy needle helped to resist the miosis induced by expression of the nucleus (7.1 versus 6.5 mm). The mydriasis maintained during irrigation aspiration was significantly greater in the group receiving adrenaline (6.6 versus 6.0 mm, p < 0.02). Their pupil diameters were also significantly larger at 20 minutes (p < 0.001) and 30 minutes (p < 0.01) into surgery. Pupillary constriction to a diameter of less than 5 mm occurred more frequently in the group not receiving adrenaline. Pulse rate and blood pressure in the 27 patients who had local anaesthesia showed no significant difference between the treatment groups (p > 0.05), and there was no significant variation from baseline (p > 0.05). Intraocular irrigation with adrenaline 1:1,000,000 is a safe and effective means of maintaining mydriasis during cataract surgery.

Administration, Topical↗

Differential P1-purinergic modulation of human Schlemm's canal inner-wall cells.

Intraocular pressure is directly dependent on aqueous humor flow into, and resistance to flow out of, the eye. Adenosine has complex effects on intraocular pressure. Stimulation of A1 and A2A adenosine receptors changes intraocular pressure oppositely, likely through opposing actions on the outflow of aqueous humor. While the cellular sites regulating outflow resistance are unknown, the cells lining the inner wall of Schlemm's canal (SC) are a likely regulatory site. We applied selective adenosine receptor agonists to SC cells in vitro to compare the responses to A1 and A2A stimulation. Parallel studies were conducted with human inner-wall SC cells isolated by a novel enzyme-assisted technique and with cannula-derived mixed inner- and outer-wall SC cells. A1 agonists increased whole cell currents of both inner-wall and cannula-derived SC cells. An A2A agonist reduced currents most consistently in specifically inner-wall SC cells. Those currents were also increased by A2B, but not consistently affected by A3, stimulation. A1, A2A, and A3 agonists all increased SC-cell intracellular Ca2+. The electrophysiological results are consistent with the possibility that inner-wall SC cells may mediate the previously reported modulatory effects of adenosine on outflow resistance. The results are also consistent with the presence of functional A2B, as well as A1, A2A, and A3 adenosine receptors in SC cells.

Anterior Eye Segment↗

The cross-species A3 adenosine-receptor antagonist MRS 1292 inhibits adenosine-triggered human nonpigmented ciliary epithelial cell fluid release and reduces mouse intraocular pressure.

PURPOSE: Antagonists to A3 adenosine receptors (ARs) lower mouse intraocular pressure (IOP), but extension to humans is limited by species variability. We tested whether the specific A3AR antagonist MRS 1292, designed to cross species, mimicks the effects of other A3AR antagonists on cultured human nonpigmented ciliary epithelial (NPE) cells and mouse IOP. METHODS: NPE cell volume was monitored by electronic cell sorting. Mouse IOP was measured with the Servo-Null Micropipette System. RESULTS: Adenosine triggered A3AR-mediated shrinkage of human NPE cells. Shrinkage was blocked by MRS 1292 (IC50 = 42 +/- 11 nM, p < 0.01) and by another A3AR antagonist effective in this system, MRS 1191. Topical application of the A3AR agonist IB-MECA increased mouse IOP. MRS 1292 reduced IOP by 4.0 +/- 0.8 mmHg at 25-microM droplet concentration (n = 10, p < 0.005). CONCLUSIONS: MRS 1292 inhibits A3AR-mediated shrinkage of human NPE cells and reduces mouse IOP, consistent with its putative action as a cross-species A3 antagonist.

Adenosine↗

Management of moderate to advanced Coats' disease.

Sixteen patients (16 eyes) with Coats' disease who had either total bullous exudative retinal detachment or macular involvement and/or at least two quadrants of exudative retinal detachment were followed for a mean period of 60.6 months. Three patients with no light perception received no treatment. Ten eyes received cryotherapy on one or more occasions and two had laser photocoagulation. One eye underwent subretinal fluid drainage, intraocular infusion and cryotherapy. In those patients who could be tested, all the treated eyes retained their initial visual acuities. All 16 eyes had an acceptable cosmesis and none progressed to painful neovascular glaucoma or phthisis bulbi. Patients with late onset disease had a more benign course.

Adolescent↗

Corneal thickness after vitrectomy and infusion with dextran solution.

We studied with pachometry the degree of corneal endothelial decompensation in rabbits undergoing extracapsular lens extraction and vitrectomy. We used 3 different infusion solutions: (1) 0.9% sodium chloride; (2) 0.45% sodium chloride with 2.5% glucose; and (3) 0.45% sodium chloride, 2.5% glucose, and 2% dextran. Vitrectomy and vitreous replacement with the last solution demonstrated the least overall increase in corneal thickness. On the basis of these observations, dextran may be a useful colloid osmotic agent in intraocular irrigating fluids to control and decrease postoperative corneal edema.

Animals↗

New indications for and technics in vitreoretinal surgery.

Vitreoretinal surgery has become a widely used ophthalmic surgical procedure since the late sixties. However, it remained an intensively developing field of surgical interventions, and indications still become wider and wider. The procedure starts with the removal of vitreous body, blood or inflammatory material from the vitreous cavity. After this, the given retinal disease, such as retinal detachment, macular hole, proliferative diabetic retinopathy, intraocular foreign body, etc. can be properly treated in situ. For that purpose a number of fine intraocular instruments, fluids, gases can be used. While the anatomical success rate can be up to 95%, the final visual outcome, due to the fact that the retina is not rarely seriously damaged, is less enthusiastic. However, a great number of previously untreatable vitreoretinal diseases can be managed in this way, nowadays.

Biocompatible Materials↗

Intraoperative acetazolamide in the prevention of intraocular pressure rise after pars plana vitrectomy with fluid-gas exchange.

PURPOSE: To assess the effect of intraoperative acetazolamide (Diamox) on postoperative intraocular pressure (IOP) in gas-filled, vitrectomized eyes. METHODS: We conducted a prospective randomized clinical trial of 63 consecutive patients undergoing pars plana vitrectomy with total fluid-gas exchange and long-acting intraocular gas tamponade. Patients were randomized by a blind draw to receive either intravenous 500 mg acetazolamide (Diamox) (Group 1) or no treatment (Group 2) at the conclusion of the operative procedure. Intraocular pressures at the conclusion of surgery (IOP-1), 4-8 hours following surgery (IOP-2), and on the first postoperative day (IOP-3) were measured using an Oculab Tono-Pen. RESULTS: Patients in Groups 1 and 2 showed similar mean IOP on postoperative day 1 (20.48+/-7.84 mmHg versus 19.89+/-7.89 mmHg). A similar incidence of IOP-2 greater than 30 mmHg (1 versus 3 patients with high IOP) and IOP-3 greater than 30 mmHg (4 versus 3 patients with high IOP) was seen. Patients in Group 1 had a lower mean IOP at 4-8 hours postoperatively (16.25+/-6.47 mmHg) than those in Group 2 (20.13+/-6.33 mmHg). No correlation could be demonstrated between IOP-1 and subsequent IOP. However, IOP on the first postoperative day (IOP-3) was strongly correlated with IOP 4-8 hours after surgery (IOP-2) (P = 0.0001). No protective effect of Diamox could be demonstrated on either IOP-2 or IOP-3. CONCLUSIONS: No protective effect against pressure rise could be demonstrated for intraoperative acetazolamide (Diamox) in the prophylaxis of IOP rise following pars plana vitrectomy and total fluid-gas exchange with long-acting intraocular gas.

Acetazolamide↗

Increases in volume, fluid content, and lens weight of eyes following systemic administration of melatonin.

Melatonin's effects were studied in male golden hamsters (Mesocricetus auratus) distributed among five surgical groups (nonoperated, sham-pinealectomized, sham-pinealectomized plus black plastic shielding of the pineal region, pinealectomized, and pinealectomized plus black plastic shielding of the pineal region) and three injection groups (vehicle only, 25 micrograms melatonin, and 2,500 micrograms melatonin). Injections (s.c.) were daily for 28 d at L11 to L11.75 in a (light:dark) L:D 14:10 artificial photoperiod. Animals (N = 112) were killed and dissected on the day after the last injection (at 55-65 d of age). None of the surgical procedures affected weights of eyes or their parts, nor did they influence the effects of administered melatonin on the eyes. Melatonin caused an increase in absolute and relative eye weight and an increase in fluid content of intraocular space. The magnitudes of these effects were positively related to melatonin dose. These same eyes had a progressively lower weight of nonlenticular tissues with low to high doses of melatonin, probably in relation to greater fluid content, and suspected increase in intraocular pressure. Lens wet and dry weights were significantly greater in animals receiving melatonin, but only at the high dose. These actions of melatonin are likely to be direct and are shown to not require the presence of the pineal. Experiments of other designs are suggested in order to determine whether the effects of the low, near physiological, dose of melatonin represent physiological actions of endogenous melatonin, synthesized and released within the eye. However, effects of large doses of melatonin on the eye are still noteworthy in relation to interpretation of experiments employing such dosages, and of disease states involving changes in intraocular pressure.

Animals↗

[A case of intraocular malignant lymphoma diagnosed by immunoglobulin gene rearrangement and translocation, and IL-10/IL-6 ratio in the vitreous fluid].

BACKGROUND: The diagnosis of primary intraocular lymphoma is difficult in many cases even with conventional cytological tests using vitreous samples. Recently new diagnostic tests, such as microdissection and polymerase chain reaction (PCR) and measurement of cytokines using intraocular samples, have been applied to the diagnosis of the disease. We report here a case where we used the new diagnostic tests and the results aided us to make a diagnosis of intraocular lymphoma. CASE: A 68-year-old woman with an initial diagnosis of bilateral idiopathic uveitis with steroid-resistant vitreous opacities underwent a vitreous biopsy. The cytological examinations of the vitreous samples revealed class III. The microdissection and PCR using the vitreous samples detected IgH rearrangement gene in the third framework (FR3A), the complementary determining region 3 (CDR3) of the VH region and Bcl-2-associated translocation. The interleukin (IL)-10 to IL-6 ratio in the vitreous fluid was greater than 100. Because the results of the examinations strongly suggested intraocular lymphoma, the patient was treated with radiation and chemotherapy. One month after the therapy, however, the patient developed multiple metastatic lesions in the brain. The clinical course of the patient together with the new diagnostic results of examinations led to a diagnosis of intraocular lymphoma. CONCLUSION: A combination of tests, such as conventional cytology, microdissection, and PCR, and cytokine assay using intraocular biopsy samples, is useful to make a diagnosis of intraocular lymphoma.

Aged↗

Some aspects of waterloadings in rabbits.

The effect of various amounts of waterload and the differences caused by oral and parenteral administration of fluids on the intraocular pressure (IOP), pupil diameter and blood osmolality were investigated. Trained rabbits were given loadings of fluids by different routes. An oral waterload of 100 ml/kg bodyweight gave an elevation of the IOP of about 12 mm Hg. Smaller amounts give a less pronounced IOP elevation. Intraperitoneal administration does not seem to increase IOP markedly. Rapid infusion of glucose 5% 15 ml/kg produces a transient and modest increase of the IOP. The mechanisms by which oral waterloading increases the IOP are discussed.

Animals↗

Temperature-dependent light damage to the retina.

We examined the ability of hypothermic infusion fluid to reduce the risk of light damage to the retina from the intraocular fiberoptic probe during vitreous surgery. Following vitrectomy, we exposed the retina of rabbits to light from an intraocular fiberoptic probe during infusion of fluid at body temperature (39 C) and compared this with exposures during infusion of room temperature fluid (22 C). Retinal irradiance was 0.33 W/cm2. Damage was determined ophthalmoscopically and histologically. Cooling the infusion fluid from body to room temperature extended the damage threshold from approximately 25 to 60 minutes. A 35-minute exposure to body temperature fluid was compared with the same exposure during infusion of room temperature fluid. While retinal and retinal pigment epithelium damage was present after the body temperature exposure, no damage was detected after the room temperature exposure. Vitreoretinal surgeons should avoid warming intraocular infusion fluids to levels above room temperature.

Animals↗