Michael A. Callahan

Prevention of Blindness after Blepharoplasty

As reported in the medical literature, approximately 68 patients have been blinded by complications of the blepharoplasty procedure. All cases have been associated with intraoperative or postoperative orbital hemorrhage. Those factors which will help blepharoplasty surgeons reduce the occurrence of orbital hemorrhage and subsequent blindness are reviewed.

Delayed Rod-Mediated Dark Adaptation Is a Functional Biomarker for Incident Early Age-Related Macular Degeneration

PURPOSE To examine whether slowed rod-mediated dark adaptation (DA) in adults with normal macular health at baseline is associated with the incidence of age-related macular degeneration (AMD) 3 years later. DESIGN Prospective cohort. PARTICIPANTS Adults aged ≥60 years were recruited from primary care ophthalmology clinics. Both eyes were required to be step 1 (normal) on the Age-Related Eye Disease Study 9-step AMD classification system based on color fundus photographs graded by experienced and masked evaluators. METHODS Rod-mediated DA was assessed at baseline in 1 eye after a photobleach using a computerized dark adaptometer with targets centered at 5° on the inferior vertical meridian. Speed of DA was characterized by the rod-intercept value, with abnormal DA defined as rod-intercept ≥12.3 minutes. Demographic characteristics, best-corrected visual acuity, and smoking status were also assessed. Log-binomial regression was used to calculate unadjusted and adjusted risk ratios (RRs) and associated 95% confidence intervals (CIs) for the association between baseline DA and incident AMD. MAIN OUTCOME MEASURES Presence of AMD at the 3-year follow-up visit for the eye tested for DA at baseline. RESULTS Both baseline and follow-up visits were completed by 325 persons (mean age, 67.8 years). At baseline, 263 participants had normal DA with mean rod-intercept of 9.1 (standard deviation [SD], 1.5), and 62 participants had abnormal DA with mean rod-intercept of 15.1 (SD, 4.0). After adjustment for age and smoking, those with abnormal DA in the tested eye at baseline were approximately 2 times more likely to have AMD in that eye (RR, 1.92; 95% CI, 1.03-3.62) by the time of the follow-up visit, compared with those who had normal DA at baseline. CONCLUSIONS Delayed rod-mediated DA in older adults with normal macular health is associated with incident early AMD 3 years later, and thus is a functional biomarker for early disease. The biological relevance of this test is high, because it assesses translocation of vitamin A derivatives across the retinal pigment epithelium and Bruchs membrane, 2 tissues with prominent age- and AMD-related pathology.

Associations Between Abnormal Rod-Mediated Dark Adaptation and Health and Functioning in Older Adults With Normal Macular Health

PURPOSE Delayed rod-mediated dark adaptation (DA) is characteristic of early age-related macular degeneration (AMD) and also can be observed in some older adults in normal macular health. We examine cross-sectional associations between rod-mediated DA and risk factors for AMD in older adults in normal macular health. METHODS The sample consisted of adults aged ≥60 years old in normal macular health per grading of fundus photos using an established disease classification system. Rod-mediated DA was measured psychophysically following a photobleach using a computer-automated dark adaptometer with targets centered at 5° on the inferior vertical meridian. The speed of DA was characterized by the rod-intercept value, with abnormal DA defined as rod-intercept ≥ 12.3 minutes. We assessed several health and functional characteristics that the literature has suggested increase AMD risk (e.g., smoking, alcohol use, inflammatory markers, apolipoproteins, low luminance visual acuity, chronic medical conditions, body mass, family history). RESULTS Among 381 participants (mean age, 68.5 years; SD, 5.5), 78% had normal and 22% had abnormal DA, with the prevalence of abnormal DA increasing with age. After age-adjustment, abnormal DA was associated with increased odds of elevated C-reactive protein (CRP), heavy use of or abstention from alcohol, high blood pressure, and drop in visual acuity under mesopic conditions. CONCLUSIONS Despite having normal macular health according to accepted definitions of AMD presence, approximately one-quarter of older adults recruited from primary eye care clinics had abnormal DA, which was associated with known risk factors for AMD, including elevated CRP.

Evaluation of the non-specific effects of catecholamine and serotonin neurotoxins by injection into the medial forebrain bundle of the rat

Low doses of 6-hydroxydopamine (6-OHDA), 5,6-dihydroxytryptamine (5,6-DHT) and 5,7-dihydroxytryptamine (5,7-DHT) that have previously been shown to produce behavioral change following intracerebral infusion were injected into the medial forebrain bundle of the rat. This site contains serotonin (5-HT), norepinephrine (NE), and dopamine (DA) fibers whose anatomical locations have been described. Damage to these fiber systems was quantified by measuring depletion of telencephalic 5-HT, NE and DA. The effects of infusions of 6-OHDA, 5,6-DHT and 5,7-DHT were compared to the effects of unequivocally non-specific electrolytic lesions and copper sulfate infusions. Survival time was varied to evaluate the amount of regeneration that could be expected over periods from 8 to 60 days. Amine levels were found to be stable over the time period examined. With the doses used, evidence was found to support the position that non-specific damage caused by general cytotoxic effects of 6-OHDA and 5,7-DHT is minimized sufficiently to permit the acquisition of useful data on the function of central catecholamine and indoleamine systems.

Fixation of the medial canthal structures: evolution of the best method.

Bullets and shrapnel mangled the medial orbital walls of World War II servicemen so frequently that ophthalmic surgeons were stimulated to find a method that would firmly and symmetrically attach the medial canthal tendon to the medial orbital wall. In many casualties the shattered eye had necessarily been removed in an adjacent field hospital, and the lacerated skin wounds loosely sutured together. When these men finally reached our definitive repair hospital two or three months had elapsed, and the canthal structures were drawn laterally. Efforts to reattach the canthal structures to the periosteum or to the stump of the tendon in the medial orbital wall with either gut or silk sutures always ended in failure and redetachment. Then the tissues were so friable that an additional three or four months had to elapse before a tertiary surgical effort could be made. Repairing canthal detachments after orbital cicatrization presented a more formidable challenge than primary repair, when simply attaching the medial canthal stump to the proximal stump with strong absorbable sutures was almost uniformly successful.

Effects of forebrain serotonin depletion on fenfluramine-induced taste aversions

Both nonspecific electrolytic and chemically specific 5,7-dihydroxytryptamine lesions of the median and dorsal raphe nuclei of the rat potentiated the suppressive effects of pairing a single injection of fenfluramine HCl with the ingestion of a novel fluid. No general alterations in fluid intake were observed as a result of the lesion. Nor did the lesions cause any significant changes in body weight. Telencephalic serotonin content was reduced by 53%-57% in the lesion groups. The study suggests that although fenfluramine may act on serotonergic systems, the drug’s effectiveness in the conditioned aversion paradigm does not depend on the integrity of the ascending serotonergic projections of the raphe. The results described here are comparable to those reported previously when lithium chloride rather than fenfluramine was used to induce an aversion in serotonin-depleted rats.

Effects of goldthioglucose lesions on central catecholamine levels in the mouse

Male and female C57 B1/6J mice were injected with goldthioglucose (GTG) to induce an obesity syndrome. Significant increases in body weight were inversely correlated with pituitary dopamine (DA) levels. Significant reductions in hypothalamic norepinephrine (NE) and DA were also noted; however, these reductions did not appear to be related to body weight gain. The GTG injections did not produce any significant alterations in telencephalic NE or DA. The damage to catecholamine neurons is discussed in relation to the endocrine abnormalities of the GTG mouse and some current hypotheses on the control of food intake.