Axial length, refractive error, and keratometry in patients with branch retinal vein occlusion.

PURPOSE: To evaluate ocular parameters that may predispose to the development of branch retinal vein occlusion (BRVO). METHODS: This prospective study included patients with unilateral BRVO evaluated in the authors' clinic. The mean period from the acute phase was 2.29 +/- 1.57 years (range 1-6 years). All patients underwent a complete ophthalmologic examination including subjective refraction, axial length measurements, and keratometry readings. The fellow eye served as a control in each patient. The variables of interest were compared between the affected eye and the fellow eye using the parametric t-test and the nonparametric Wilcoxon test. RESULTS: Twenty-four consecutive patients (14 women, 10 men, mean age 62.4 years) were included in the study. The mean axial length in the affected eye was significantly shorter compared to the mean fellow eye length. No difference was found between the two eyes in mean subjective refraction or mean keratometry readings. CONCLUSIONS: The authors found that eyes with BRVO have a shorter axial length compared to the fellow eye in the same patient.

Laser in situ Keratomileusis Following Acanthamoeba Keratitis.

PURPOSE: Although data regarding reactivation of microbial corneal infections following LASIK is scarce, the use of excimer laser is known to be an efficient trigger for the reactivation of herpes simplex keratitis. With this in mind, the use of excimer laser, including LASIK, theoretically places the cornea at potential risk for reactivation of other microbial infections. Acanthamoeba keratitis is a severe, painful, sight-threatening infection most often associated with soft contact lens use. Treatment of Acanthamoeba keratitis is notoriously difficult, and despite prolonged administration of anti-protozoal agents such as polyhexamethylene, propamidine isethionate (Brolene), and neomycin, recurrence of the keratitis can occur. Postoperative reactivation following penetrating keratoplasty performed for visual rehabilitation in patients with previous Acanthamoeba keratitis has been documented, and LASIK, when performed on these patients, may raise concerns about the potential risk of reactivation of the infection. METHODS: We report the case of a myopic patient with previous Acanthamoeba keratitis and corneal scarring who underwent LASIK without preoperative anti-protozoal prophylaxis. RESULTS: During a 6-month follow-up period after LASIK, no recurrence of the infection was noted. CONCLUSION: In our patient who previously suffered from Acanthamoeba keratitis and underwent LASDX, no reactivation of the infection was seen. [J Refract Surg 2000;16(suppl):S251-S252].

Complications of excimer laser photorefractive keratectomy for myopia.

PURPOSE: To evaluate the safety and complication rates of excimer laser photorefractive keratectomy (PRK). SETTING: Assutah Laser Center, Tel-Aviv, Israel. METHODS: This retrospective study evaluated the complication rate after PRK in 825 consecutive patients who had PRK for myopia and had a follow-up of at least 12 months. RESULTS: At 12 months postoperatively, 4.0% of patients suffered from overcorrection and 8.6% from undercorrection. Induced astigmatism developed in 1.4% of all operated eyes. Three percent of the patients had haze, and 3.6% reported glare or halos. Twenty-three eyes (2.7%) lost one line or more of best corrected visual acuity (BCVA). Ptosis developed in 0.4% of the eyes, and 3.5% had a significant increase in intraocular pressure resulting from corticosteroid treatment. There were no complications in 678 eyes (82.5%). CONCLUSION: Eighty-two percent of eyes having PRK did not develop complications. In 18.0% one or more complication, mainly undercorrection, overcorrection, or loss of BCVA, occurred.

Macular hemorrhage after excimer laser photorefractive keratectomy.

We describe three patients with high myopia, 13.0 to 20.0 diopters (D), who had typical myopic macular hemorrhages 1 to 6 months after photorefractive keratectomy (PRK). The hemorrhages eventually resolved, with resultant permanent decrease in vision and pigmentary and atrophic changes in the macula. Highly myopic eyes are predisposed to bleeding in areas of lacquer cracks and to myopic choroidal neovascularization formation. Awareness of potential retinal pathology in patients having PRK and follow-up retinal examinations are warranted.

Comparison of keratometric values of healthy and diseased eyes measured by Javal keratometer, EyeSys, and PAR.

PURPOSE: To compare the simulated keratometric results of the PAR CTS and the EyeSys corneal imaging systems with Javal keratometer readings in keratoconus eyes, in eyes after corneal grafting, and in healthy eyes. SETTING: Cornea Service, Wills Eye Hospital, Philadelphia, Pennsylvania, USA. METHODS: This prospective study evaluated 69 patients divided into three groups (keratoconus; 6 to 12 months postkeratoplasty; normal corneas) treated at the cornea service. The eyes were measured with each of the three instruments. Keratometry results and number of attempts needed to obtain the results were collected. RESULTS: Thirty keratoconus, 18 transplanted, and 21 normal corneas were examined. The PAR CTS Imaged all corneas and the EyeSys, 86% (P = .000627). The PAR CTS and Javal flat and steep K-readings in all three groups were the same. The EyeSys simulated keratometry results were lower than those of Javal keratometer in the flat K (P < .00001) and steep K (P < .00001) in the normal group and in the steep K in the transplanted cornea group (P = .00823). The EyeSys also measured less astigmatism than the Javal in the normal (P = .00124) and transplanted cornea groups (P = .00376). CONCLUSION: The PAR CTS was better able than the EyeSys to provide keratometric values that agreed with those obtained with the Javal keratometer.

Excimer laser reablation.

BACKGROUND AND OBJECTIVE: To evaluate the outcome of repeated excimer laser keratectomy after photorefractive keratectomy (PRK). PATIENTS AND METHODS: A retrospective study of 32 of 1000 consecutive patients who had a follow-up of at least 12 months and who underwent repeated PRK in the Assutah Laser Center. RESULTS: The mean spherical equivalent (SE) declined significantly as a result of the repeated treatment. As opposed to zero eyes before re-treatment, 19 of 29 eyes (66%) achieved SE of within +/-1 D 6 months after re-treatment. Before re-treatment, 20 of 32 eyes (62%) had medium or severe haze, whereas after re-treatment only 1 of 29 eyes (3%) had medium haze, and none of the eyes had severe haze. At 6 months after reoperation, visual acuity had improved to 20/36, a significant improvement to the mean log MAR equivalent of 20/40 before re-treatment, yet still significantly worse than the log MAR equivalent before initial ablation which was 20/30. CONCLUSION: Repeated excimer laser PRK has the potential for successful treatment of undercorrection, regression, and haze occurring after an initial PRK.

Late onset corneal haze after photorefractive keratectomy for moderate and high myopia.

BACKGROUND: Corneal haze after photorefractive keratectomy (PRK) usually appears within 4 weeks after the procedure. A new type of corneal haze, starting relatively late after PRK, is reported. METHODS: The authors reviewed the files of their first 1000 consecutive patients who completed a follow-up of 12 months or more and identified all those who had clear corneas for at least 4 months, after which corneal haze appeared. The clinical course in these patients was evaluated. RESULTS: Late onset corneal haze (LOCH) had occurred in 18 eyes of 17 patients (incidence, 1.8%), appearing 4 to 12 months after PRK and resulting in decreased visual acuity and regression. Treatment with topical steroids or reoperation resulted in partial reversibility of haze and regression. CONCLUSIONS: A new entity of LOCH is described. The appearance of LOCH suggests that corneal healing and remodeling continue for at least 1 year after PRK.

Delay of corneal wound healing in patients treated with colchicine.

BACKGROUND: Colchicine has a known adverse effect on wound healing through its inhibitory effect on tubulin-dependent cell functions and through collagenase activation. In the cornea, it has been shown in animal and in vitro studies to inhibit epithelium mitosis, fibroblast mitosis and migration, as well as to reduce collagen deposition. The authors report on two patients with corneal ulcers refractory to conventional treatment while the patients were undergoing oral colchicine therapy. CASE REPORTS: The first patient was an 86-year-old woman who had been treated with oral colchicine because of rheumatoid arthritis. She was admitted to the authors' department with a deep corneal ulcer in the right eye for which she had been treated for 3 weeks with local antibiotics without any improvement. The second patient, a 60-year-old woman, was hospitalized because of a corneal ulcer in her left eye. She had been receiving oral colchicine therapy for mixed connective tissue disease. Treatment with local antibiotics was initiated but the condition of the eye worsened, ultimately resulting in corneal perforation. RESULTS: Withdrawal of oral colchicine therapy was followed by rapid corneal wound healing in both patients. CONCLUSION: The findings in these two patients suggest that colchicine may delay corneal wound healing. The authors suggest that in patients with corneal ulcers refractory to conventional treatment who are receiving colchicine, cessation of colchicine therapy should be considered.

Do silent brain infarctions predict the development of dementia after first ischemic stroke?

BACKGROUND AND PURPOSE: Silent brain infarctions (SBI) are common findings in advanced age, but their relationship to dementia is still uncertain. The present study was designed to evaluate whether SBI predict the development of dementia after first clinical ischemic stroke. METHODS: We blindly studied admission CT scans of 175 consecutive nondemented patients presenting with ischemic stroke that clinically was their first stroke episode. SBI were defined as CT evidence of infarcts not compatible with the acute event. The patients were subsequently followed for their mental state for 5 years. Survival analysis, wherein onset of dementia was the end point, was performed on the total sample population and conducted separately on those with and without SBI at admission. RESULTS: Dementia developed in 56 patients (32%), including 22 of the 63 (35%) with SBI and 34 of the 112 (30%) without SBI. Thus, dementia was not related to SBI. CONCLUSIONS: Our data indicate that SBI do not predict the development of dementia after stroke.

The mydriatic effect of topical glycopyrrolate.

BACKGROUND: Glycopyrrolate, an anticholinergic agent that does not cross the blood-brain barrier, has several indications, but its mydriatic effect has never been tested. This study was carried out in order to compare the mydriatic effect of glycopyrrolate 0.5% to that of atropine sulfate 1%. METHODS: Glycopyrrolate 0.5% and atropine 1.0% were instilled separately in the eyes of albino rabbits. Pupil diameter and intra-ocular pressure were monitored. RESULTS: Mydriasis was noted within 5 min of glycopyrrolate instillation, reached near-maximal level at 15 min and persisted for 1 week. Glycopyrrolate 0.5% showed a faster, stronger and more persistent mydriatic effect than atropine 1.0%. Administration of glycopyrrolate 0.5% solution b.i.d. for 1 week did not affect intra-ocular pressure or produce any adverse reaction. CONCLUSION: Glycopyrrolate solution has the potential to deliver an ocular anticholinergic effect without causing associated central anticholinergic hazards.

Effects of heat-exercise stress, NBC clothing, and pyridostigmine treatment on psychomotor and subjective measures of performance.

This study investigated the effects of pyridostigmine pretreatment, NBC protective gear, and heat-exercise exposure on psychomotor performance and subjective sensations in eight healthy male volunteers. Exercise in heat enhanced performance of vertical addition (+7.3%, p less than 0.001) but prolonged the reaction time (+4.4%, p less than 0.01). The effects of pyridostigmine, protective gear, and the interactions between the various stressors were not significant. Cognitive performance was not dependent on body core temperature. Multiple complaints of subjective discomfort arose from wearing the protective garment. The results suggest the existence of a significant subjective discomfort but an absence of major cognitive decrements in a multiple-stresses state of chemical warfare alertness.

Trilateral retinoblastoma.

Retinoblastoma is the most common intraocular malignancy of childhood. Trilateral retinoblastoma is a syndrome characterized by bilateral ocular retinoblastoma in conjunction with an intracranial neuroblastic neoplasm in the pineal body, or in supraseller or parasellar location. We report the case of a three year old girl with trilateral retinoblastoma and review the literature on this subject.

Prevention of the rise in intraocular pressure following neodymium-YAG posterior capsulotomy using topical clonidine.

We studied the ability of topical clonidine, an alpha-agonist, to suppress the acute rise in intraocular pressure (IOP) following neodymium-YAG posterior capsulotomy (YPC). In a randomized controlled trial 63 eyes were pretreated with one drop of either 0.25% clonidine or saline 1 h before performing YPC and immediately following the procedure. The greatest IOP rise in the saline treated eyes occurred in the second hour after YPC, when the mean (+/- SD) IOP rose from a baseline pressure of 12.7 +/- 3.2 to 18.7 +/- 10.7 mmHg. In clonidine treated eyes, the IOP fell from a mean of 11.9 +/- 3.4 to 9 +/- 3.3 mmHg 2 h postoperatively. In the saline treated group 9 eyes (27%) developed an IOP rise greater than 10 mmHg. Clonidine proved to be highly effective in preventing the rise in IOP following YPC.

[Procurement of corneas for transplantation].

We prospectively studied all deaths in this hospital from July 1, 1989 through December 31, 1989 for possible eye donations. During this period 539 patients died, of whom, 219 were suitable candidates for donation, and 61 donations were obtained (11.3%). In the course of the study the procurement rate increased progressively as a result of a higher level of effort and awareness by the medical staff.

Obtaining consent for eye donation.

We prospectively studied all the deaths that occurred in Sourasky Medical Center (Ichilov Hospital), Tel Aviv, from 1 July through 30 September 1989 for possible eye donation. Of the 135 suitable candidates 29 donations were obtained (21.5%). In the course of the study the procurement rate progressively increased as a result of a higher level of effort and awareness by the hospital medical staff.

Heat-exercise performance of pyridostigmine-treated subjects wearing chemical protective clothing.

Pyridostigmine bromide is currently the pretreatment of choice for operation in a chemical warfare (CW) environment. Under CW conditions, subjects are exposed to thermal stress caused by CW protective clothing. This investigation was conducted to determine if pyridostigmine affects various physiological and biophysical parameters of human temperature regulation in subjects wearing CW protective clothing. Pyridostigmine was administered orally in a randomized double-blind cross-over study in four doses of 30 mg every 8 h. An average of 33% whole blood cholinesterase inhibition was induced in the pyridostigmine treated group 4 h after ingestion of last tablet. The subjects were exposed to 170 min exercise-heat stress (Tdb = 33 degrees C; rh = 60%) consisting of 60 min in a sitting position and two 50-min walks (1.39 m.s-1, 5% grade) separated by 10 min of rest. Non-evaporative heat exchange was significantly higher, -14.0 and -10.6 W.m-2 (p less than 0.03), for the pyridostigmine-treated subjects. No additional differences were found between treatments in the physiological responses and heat balance parameters at the end of exposure: heart rate (HR) was (mean +/- S.D.) 154 +/- 16 and 151 +/- 24 bpm, rectal temperature (Tre) was 39.0 +/- 0.4 and 38.9 +/- 0.2 degrees C, heat storage over the 2 h of exercise was 62 +/- 15 and 70 +/- 15 W.m-2, and sweat rate was 832 +/- 185 and 748 +/- 52 g.h-1, in the pyridostigmine and placebo treatments, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)