Reduced plasma cortisol binding to albumin in ocular hypertension and primary open-angle glaucoma.

PURPOSE: To compare plasma cortisol binding as well as total plasma cortisol, free cortisol and percent free cortisol in normals, ocular hypertensives and primary high pressure open-angle glaucomas. METHODS: Blood samples were obtained on outpatient visits of 18 normals, 19 ocular hypertensives and 18 primary open-angle glaucomas. Plasma cortisol binding was determined after the endogenous steroids were removed by charcoal absorption. Scatchard analysis was used to determine both the affinity of binding and the cortisol binding capacity of corticosteroid binding globulin and albumin. Plasma total and free cortisol were measured by radioimmunoassay. RESULTS: Both the ocular hypertensive and the open-angle glaucomas in comparison to normals were found to have a highly significant reduced cortisol binding capacity to albumin (p = 0.006) with a borderline significantly increased binding affinity to plasma corticosteroid binding globulin (p = 0.0495) and no significant difference in binding affinity to albumin or cortisol binding capacity to plasma globulin. Both the ocular hypertensives and the open-angle glaucomas in comparison to normals were found to have significantly elevated levels of free cortisol (p = 0.012) and percent free cortisol (p = 0.003). Multivariate analyses showed that the reduced cortisol binding capacity to albumin was significantly associated with an increased percent free cortisol, with ocular hypertension and open-angle glaucoma and with male gender. CONCLUSION: Both ocular hypertension and primary open-angle glaucoma are associated with elevated levels of plasma free cortisol which are related to a reduced cortisol binding capacity to albumin.

Prophylactic use of apraclonidine for intraocular pressure increase after Nd:YAG capsulotomies.

We evaluated the prophylactic effect of 1% apraclonidine HCl in controlling the increase in intraocular pressure after Nd:YAG posterior capsulotomy in a large, multicenter double-masked clinical trial. One hundred sixty-four patients were enrolled into the apraclonidine-treated group, and 165 into the vehicle-treated group. The incidence of increase in intraocular pressure (greater than 5 mm Hg) in the apraclonidine-treated group (7%, 11 of 163 patients) was significantly less than that in the vehicle-treated group (39%, 64 of 164 patients). Similarly, the mean maximal change in intraocular pressure in the apraclonidine-treated group (1.3-mm Hg decrease) was significantly different from the increase in the vehicle-treated group (5.3-mm Hg increase). Few adverse reactions were observed. The risk for significant loss of visual function after Nd:YAG laser posterior capsulotomy, combined with the efficacy and relative safety of prophylactic apraclonidine, suggest its addition to the treatment armamentarium.

Increased plasma noncortisol glucocorticoid activity in open-angle glaucoma.

Total biologic plasma glucocorticoid activity of normal, ocular hypertensive, and open-angle glaucoma patients was compared using a glucocorticoid receptor-based competitive binding assay. Multiple linear-regression analysis was used to adjust for the effects of significant ocular and nonocular variables, including therapy for glaucoma. The glaucoma patients had significantly greater plasma glucocorticoid activities than did normal subjects. A comparison of receptor-based assay values to values obtained with a cortisol radioimmunoassay showed that significant amounts of biologic glucocorticoid activity in the plasma of the glaucoma patients could not be explained by cortisol alone. In the normal and ocular hypertensive groups, however, virtually all of the plasma glucocorticoid activity could be accounted for by cortisol. These results suggest that in open-angle glaucoma patients, noncortisol glucocorticoids are responsible for elevating biologic plasma glucocorticoid activity. Thus, open-angle glaucoma may be associated with a disturbance of the hypothalamic-pituitary-adrenal axis that produces increased plasma levels of both cortisol and other noncortisol glucocorticoids.

Enhanced accuracy is necessary for refractive surgery instrumentation.

New optical zone markers, diamond knives, and gauge blocks were ordered from a random selection of manufacturers and inspected by an independent metallurgical engineer. This study revealed workmanship flaws and poor instrument accuracy. None of the 26 optical zone markers examined came with instructions as to whether the incisions were to be carried to or from the inside diameter or the outside diameter of the corneal impression made by the marker. Two markers had a 100 microns or greater error in their centering devices and one had a centering device off center by 210 microns. Two of the seven diamond micrometer knives had broken blade tips and uneven footplates; two knives had misaligned blades and uneven footplates, one knife had extremely roughly finished footplates, and one knife had a 100 microns error in its micrometer. All the knives had a wobble in the blade shaft upon advancement and had rounded footplates, making blade extension verification difficult. Five of seven blade gauges were accurate to within 10 microns; two had errors of more than 60 microns which could lead to incisions too deep or too shallow and micro- or macroperforations of the cornea during refractive surgery. It is recommended that all refractive surgery instruments be carefully inspected under a high power micron-level microscope at the time of purchase and routinely thereafter.

Refractive evaluation of astigmatic keratotomy procedures.

We evaluated the efficacy of three transverse incision astigmatic keratotomy procedures using a vector analysis that enabled us to determine the magnitude of the effect and the axis in which it occurred. These procedures were used for low levels of astigmatism (0.5 diopter [D] to 3.75 D): (1) staggered, radial-touching transverse (T) incisions, (2) non-radial-touching T incisions, and (3) T incisions with interrupted radial. Most procedures were performed in conjunction with radial keratotomy for spherical correction of myopia. The non-radial-touching T procedure was the least effective method of reducing astigmatism. The staggered, radial-touching T and T with interrupted radial procedures were equally effective in reducing over 93% (on the average) of the preoperative astigmatism. Of these two procedures, the T with interrupted radial procedure was the most accurate, with the effect of the surgery deviating less than ten degrees from the desired axis in over 70% of the eyes.

Small incisions to control astigmatism during cataract surgery.

Astigmatic changes in three series of cataract surgical procedures were compared. Two series comprised eyes having phacoemulsification and implantation of a foldable silicone lens through a 3.0 mm to 4.0 mm incision or a 5.8 mm diameter polymethylmethacrylate (PMMA) lens through a 6.0 mm incision. The third series comprised eyes having a planned extracapsular cataract extraction (ECCE) procedure through a 10.0 mm incision and implantation of a PMMA posterior chamber lens. Surgically induced cylinder changes were compared by examining preoperative and postoperative dioptric cylinder power changes without regard to axis changes and by using vector analysis to compute induced cylinder for cases with axis changes. Both phacoemulsification series had similar mean induced cylinder levels, which were significantly less than mean induced cylinder in the ECCE group at both three and six months after surgery. Over 70% of the eyes in the two small incision phacoemulsification groups achieved an uncorrected visual acuity of 20/40 or better at three months, whereas only 28% of the ECCE group achieved that acuity. We concluded that the phacoemulsification procedure induced significantly less astigmatism and provided faster visual rehabilitation than the ECCE procedure. Furthermore, the use of small diameter PMMA IOLs inserted through small incisions minimized surgically induced cylinder in a way comparable to the use of foldable silicone implants, while maintaining good visual results with fewer postoperative complications.

Hexagonal keratotomy for correction of low hyperopia: preliminary results of a prospective study.

Fifteen sighted eyes of 11 patients had hexagonal keratotomy for the correction of low hyperopia. Mean preoperative hyperopia of +3.21 diopters (range +1.75 to +5.50) was reduced a mean of 2.16 diopters (range 0 to -3.25) and keratometry was increased a mean of +2.22 diopters (range +0.75 to +3.71). Follow-up averaged 9.5 months (range 2.0 to 17.5). Ten of the 15 eyes (67%) had at least six months follow-up. No eye had better than 20/80 uncorrected visual acuity preoperatively. Fourteen eyes (93%) had 20/80 or better uncorrected acuity at the most recent postoperative visit. Nine of the 15 eyes (60%) had uncorrected acuity of 20/40 or better. Refractive spherical equivalent appeared to stabilize by three months for most patients. Astigmatism was increased a mean of only +0.02 diopter and no serious complications occurred. Further follow-up is required to assess the safety and efficacy of hexagonal keratotomy for reducing low levels of hyperopia.

Glare disability devices for cataractous eyes: a consumer's guide.

We evaluated five commercially available glare testers to determine how accurately each device predicted outdoor Snellen acuity in cataract patients. Predicted outdoor Snellen acuity was compared to actual Snellen outdoor acuity for the Miller-Nadler glare tester, the brightness acuity tester (BAT), the InnoMed true vision analyzer (TVA), the VisTech VCT 8000, and the EyeCon 5. All five devices were evaluated in a single series of eyes. We ranked the five glare testers as follows based upon their ability to predict outdoor Snellen acuity within one Snellen line: (1) BAT (73%), (2) TVA (69%), (3) VisTech VCT 8000 (56%), (4) Miller-Nadler (47%), and (5) EyeCon 5 (15%). All five devices were also evaluated for their capacity to provide false negative or false positive results and for testing time per eye, test difficulty level for the patient, versatility, upgrading capacity, examining room adaptability, and price. We concluded that glare testing of cataract patients is necessary to measure visual disability and that glare testing devices vary in their ability to predict outdoor vision.

The relationship between indoor and outdoor Snellen visual acuity in cataract patients.

One hundred six cataractous eyes of 78 patients were evaluated to examine the relationship between indoor and outdoor Snellen visual acuity. While 81 of all cataractous eyes (76.4%) had Snellen visual acuities of 20/40 or better when tested indoors, only 33 eyes (31.2%) had 20/40 or better Snellen visual acuities when tested outdoors facing the sun. When tested indoors, only three eyes (2.8%) had Snellen visual acuities worse than 20/80, while 31 eyes (29.2%) had outdoor Snellen visual acuities worse than 20/80. Ten eyes (9.4%) had outdoor Snellen visual acuities worse than 20/200. Seventy-four eyes (69.8%) had outdoor visual acuities that were at least two Snellen lines worse than those measured indoors and 23 eyes (21.7%) had outdoor visual acuities that were at least five Snellen lines worse. The median difference between indoor and outdoor visual acuity was three Snellen lines. The need for increased precision in the ability to assess outdoor "real world" vision while in the ophthalmologist's examination room is discussed. Clearly, indoor Snellen visual acuity alone is insufficient to evaluate functional visual impairment in cataract patients.

The relationship between cataract type and glare disability as measured by the Miller-Nadler glare tester.

Cataract patients were tested for glare disability using the Miller-Nadler glare tester. Predicted outdoor visual acuity was then compared with the actual outdoor visual acuity. The Miller-Nadler glare test scores predicted actual outdoor visual impairment to within one Snellen line in 46.7% of the eyes, underestimated actual outdoor visual impairment by more than one Snellen line in 31.5% of the eyes, and overestimated outdoor visual impairment by more than one Snellen line in 21.7% of the eyes. Overall, 64.1% of the eyes had outdoor vision which was more closely predicted by their glare scores than by their indoor Snellen acuity. When the cataractous eyes were divided into three categories, eyes with pure nuclear sclerosis, eyes with nuclear sclerosis and posterior subcapsular opacities, and eyes with all other cataractous combinations, predictability differences were observed. Although we found that actual outdoor visual acuities were not precisely predicted by disability glare scores in a substantial proportion of our subjects, the glare scores were considerably more predictive than indoor Snellen acuity. Further development and field testing of glare testing devices as predictors of outdoor visual impairment is necessary.

Complications associated with STAAR silicone implants.

We compared the incidence of various complications in consecutive series of cases in which 76 eyes received STAAR silicone intraocular implants and 76 eyes received small incision IOLAB G708G polymethylmethacrylate (PMMA) intraocular implants. All surgeries were performed by the same surgeon employing the same phacoemulsification technique. A higher incidence of lens subluxation, lens repositioning, corneal edema, and elevated intraocular pressure was observed in the eyes receiving STAAR silicone implants than in the eyes receiving IOLAB PMMA implants. In addition, a YAG laser posterior capsulotomy could not be performed through several STAAR silicone RMX 1 model implants. An invasive pars plana posterior capsulotomy was necessary in these eyes. We also found that the STAAR silicone RMX 3 model implants were often pitted by the YAG laser during successful posterior capsulotomies. Despite these problems, the STAAR silicone intraocular lens group achieved corrected vision similar to the PMMA lens group.

Phacoemulsification devices: a consumer's report.

This report deals with our evaluation of six phacoemulsification devices tested at the Neumann Eye Institute (two additional devices have been evaluated since this paper was presented at the ASCRS meeting). The devices were compared for operating cost of the first 1,000 cases, dependability, ease of usage, and level of safety for the patient.

Increased concentration of glucocorticoid receptors in rabbit iris--ciliary body compared to rabbit liver.

Dexamethasone binding to both rabbit iris-ciliary body and rabbit liver glucocorticoid receptors was compared by means of a batch assay in which the binding components were adsorbed to hydroxylapatite. The results showed that homogenates of both the rabbit iris-ciliary body and the rabbit liver contained a single class of high-affinity receptors. Binding affinity was virtually identical for the two receptors. A comparison of total binding sites in homogenates of the iris-ciliary body and the liver revealed that the iris-ciliary body glucocorticoid receptor was present in nearly twice the concentration of the hepatic receptor.