Faculty Bibliography

Scientific understanding of the role of development in conservation has been hindered by the quality of evaluations of integrated conservation and development projects. We used a quasi-experimental design to quantitatively assess a conservation and development project involving commercial butterfly farming in the East Usambara Mountains of Tanzania. Using a survey of conservation attitudes, beliefs, knowledge, and behavior, we compared 150 butterfly farmers with a control group of 170 fellow community members. Due to the nonrandom assignment of individuals to the two groups, we used propensity-score matching and weighting in our analyses to control for observed bias. Eighty percent of the farmers believed butterfly farming would be impossible if local forests were cleared, and butterfly farmers reported significantly more participation in forest conservation behaviors and were more likely to believe that conservation behaviors were effective. The two groups did not differ in terms of their general conservation attitudes, attitudes toward conservation officials, or knowledge of conservation-friendly building techniques. The relationship between butterfly farming and conservation behavior was mediated by dependency on butterfly farming income. Assuming unobserved bias played a limited role, our findings suggest that participation in butterfly farming increased participation in conservation behaviors among project participants because farmers perceive a link between earnings from butterfly farming and forest conservation.

Vitreomacular traction (VMT) caused visual symptoms in two healthy young adults but spontaneously resolved within four weeks without any sequelae. Optical coherence tomography (OCT) and fundus photographs proved vital in documenting the rare complete resolution of VMT. It is prudent to monitor for spontaneous resolution of VMT in young healthy adults.

OBJECTIVE: To treat binocular diplopia secondary to macular pathology. METHODS: Seven patients underwent evaluation and treatment. All had constant vertical diplopia caused by various maculopathies, including subretinal neovascularization, epiretinal membrane, and central serous retinopathy. Visual acuity ranged from 20/20 to 20/30 in the affected eye. All except 1 patient had a small-angle, comitant hyperdeviation with no muscle paresis. Sensory evaluation demonstrated peripheral fusion and reduced stereoacuity. Neither prism correction nor manipulation of the refractive errors corrected the diplopia. A partially occlusive foil (Bangerter) of density ranging from 0.4 to 1.0 was placed in front of the affected eye to restore stable, single vision. RESULTS: The Bangerter foil eliminated the diplopia in all patients. Two patients elected not to wear the foil; 1 patient was afraid of becoming dependent, and the other was bothered by the visual blur. Visual acuity in the affected eye was reduced on average by 3 lines. All patients maintained the same level of sensory fusion, with only 2 having reduced stereoacuity. Symptoms returned when the foil was removed or its density was reduced. CONCLUSION: Low-density Bangerter foils provide an effective, inexpensive, and aesthetically acceptable management for refractory binocular diplopia induced by macular pathology, allowing peripheral fusion to be maintained

PURPOSE: To determine the applicability of laser segmentation for severing fibrovascular tissue and hyaloid interfaces in the treatment of tractional complications of proliferative diabetic retinopathy. METHODS: A prototype neodymium:yttrium-lithium-fluoride (Nd:YLF) picosecond pulse photodisruptive laser was used in eight eyes (seven patients) with proliferative diabetic retinopathy as part of a Food and Drug Administration-approved phase 1 protocol. There were three indications for treatment: type I: distortion and shallow elevation of the macular caused by taut, adherent, posterior hyaloid interface (two eyes); type II: traction retinal detachment involving the fovea (two eyes); and type III: fovea-threatened, traction retinal detachment (four eyes). Traction release was accomplished by laser segmentation of the detached hyaloid interfaces and fibrotic, contracted proliferative tissue. The Nd:YLF uses low pulse energy (0.10 mJ, 1,000 pulses per second for 10 consecutive seconds) that allows tissue cutting near the retinal surface. RESULTS: Both type I eyes had relief of traction forces; visual acuity improved from 20/400 to 20/50 in one eye; the other remained stable. Of the two type II eyes, one had anatomic reattachment of the fovea with improvement in visual acuity (hand movements to 20/50); the second required vitrectomy. Of the four type III eyes, all had anatomic improvement; three maintained pretreatment acuity; the fourth eye developed vitreous hemorrhage at 6 months and underwent vitrectomy. Three treatments (two eyes) caused vitreous hemorrhage that resulted in a transient drop in acuity (1 to 2 lines). No patient developed a retinal break or choroidal hemorrhage. CONCLUSION: In a small pilot study, the Nd:YLF laser segmented proliferative tissue near the retinal surface and elevated hyaloid interfaces. In selected cases, this may enable flattening of traction retinal detachment or release of retinal distortion

BACKGROUND: Optic disc swelling is a rare sequela of blunt ocular trauma. METHODS: The authors examined three young patients who had an unusual post-traumatic optic neuropathy in which protracted swelling of the optic nerve head was the salient clinical feature. RESULTS: Associated choroidal ruptures in two patients suggested a contrecoup mechanism of injury to the optic nerve at its junction with the globe. All patients had partial recovery of vision over months, concurrent with resolution of the nerve head swelling and development of optic disc pallor. CONCLUSION: Despite its protracted course, posttraumatic optic disc swelling appears to be associated with a favorable prognosis for visual recovery

Systemic hemorheologic abnormalities may play a part in the pathogenesis of central retinal vein occlusions. A statistically significant elevation of plasma viscosity was found in patients with acute central retinal vein occlusion compared with control patients. Local retinal blood flow parameters including arteriovenous passage time and mean arterial dye bolus velocity were significantly altered in the central retinal vein occlusion patients compared with age-matched controls at baseline examination. We performed a randomized, prospective, single-blind clinical investigation to determine the effect of hemorheological manipulation on the clinical course and retinal blood flow of eyes with central vein occlusion. Hemodilution included plasma expansion with hydroxyethyl-starch, withdrawal of whole blood if the hematocrit was above 42%, and rheologic manipulation with parenteral pentoxifylline. We found a statistically significant improvement in visual acuity at 1 year post-treatment for the treated group compared with the control group (increase of visual acuity of 1.5 lines vs decrease of 1.5 lines). The retinal blood flow parameters were markedly improved soon after the institution of therapy, and this may have contributed to the improvement in visual acuity in the treated group. There was no statistically significant difference between the two groups in the progression to ischemic central vein occlusion