Search PubMed⌕ Search

Biomedical subjects

S L Fine

Publications and source records attributed to S L Fine.

At least 19 recordsLinked to original sources
PubMed1998

The sensory world of the platypus.

Vision, audition and somatic sensation in the platypus are reviewed. Recent work on the eye and retinal ganglion cell layer of the platypus is presented that provides an estimate of visual acuity and suggests that platypus ancestors may have used vision, as well as the bill organ, for underwater predation. The combined electroreceptor and mechanoreceptor array in the bill is considered in detail, with special reference to the elaborate cortical structure, where inputs from these two sensory arrays are integrated in a manner that is astonishingly similar to the stripe-like ocular dominance array in primate visual of cortex, that integrates input from the two eyes. A new hypothesis, along with supporting data, is presented for this combined mechanoreceptive-electroreceptive complex in platypus cortex. Bill mechanoreceptors are shown to be capable of detecting mechanical waves travelling through the water from moving prey. These mechanical waves arrive after the electrical activity from the same prey, as a function of distance. Bimodal cortical neurones, sensitive to combined mechanical and electrical stimulation, with a delay, can thus signal directly the absolute distance of the prey. Combined with the directional information provided by signal processing of the thousands of receptors on the bill surface, the stripe-like cortical array enables the platypus to use two different sensory systems in its bill to achieve a complete, three-dimensional 'fix' on its underwater prey.

Animals↗
PubMed1998

A model of the incidence and consequences of choroidal neovascularization secondary to age-related macular degeneration. Comparative effects of current treatment and potential prophylaxis on visual outcomes in high-risk patients.

OBJECTIVE: To describe the comparative impact of current and preventive treatments on incidence of choroidal neovascularization (CNV) and severe vision loss in patients with bilateral soft drusen (BSD). DESIGN: Stochastic model. SETTING: US population. PATIENTS: Prevalence cohort of white patients 43 years or older with BSD. INTERVENTIONS: Application of prophylaxis of 10% to 50% efficacy to 1 or both eyes of patients with BSD, application of laser photocoagulation to eligible CNV lesions, or both. MAIN OUTCOME MEASURES: Proportion of patients with BSD after 10 years with unilateral and bilateral CNV and resultant unilateral and bilateral vision loss to visual acuity of 20/200 or worse. RESULTS: The natural history of patients with BSD generated by the model shows that 12.40% of these patients develop either unilateral or bilateral CNV within 10 years of their entry into the BSD prevalence cohort. Bilateral disease occurs in 3.86% of patients with BSD within 10 years. The proportion of patients with BSD becoming legally blind from CNV within 10 years is 2.54% if no treatment is performed. Current laser treatment for CNV decreases the proportion with legal blindness within 10 years to 2.24%. The addition of a preventive treatment of 10% efficacy applied bilaterally to the current laser treatment regimen decreases the proportion with legal blindness to 1.86%; a 25% effective preventive treatment decreases it to 1.34%. Comparatively, preventive treatment of 10% and 25% efficacy given to the fellow eye only after the first eye has developed CNV decreases the proportion of legally blind patients at 10 years only to 2.06% and 1.77%, respectively. All outcomes vary with sex and age at entry into the BSD cohort. CONCLUSIONS: Patients with BSD face a 12.40% risk of developing CNV within 10 years. The addition of even a modest (10% effective) bilateral preventive treatment to the current regimen for CNV would more than double the prevention of legal blindness in the BSD population relative to current laser treatment; a preventive treatment of 33% efficacy more than halves the rate of legal blindness caused by CNV. Preventive treatment given to the fellow eye only after the first develops CNV has substantially less impact.

Adult↗
PubMed1998

Foveolar choroidal blood flow in age-related macular degeneration.

PURPOSE: To compare measurements of the foveolar choroidal blood circulation in subjects with nonexudative, age-related macular degeneration (AMD) with those of control subjects. METHODS: Laser Doppler flowmetry was used to assess relative choroidal blood velocity (ChBVel), volume (ChBVol), and flow (ChBFlow) in the center of the fovea. Measurements were obtained in 20 eyes of 20 subjects with 10 or more large drusen, visual acuity of 20/32 or better, and no evidence of choroidal neovascularization. Findings obtained in these subjects were compared with those of 10 eyes of 10 age- and blood pressure-matched control subjects with no large drusen. Foveolar choroidal blood flow measurements were obtained by asking the study participants to fixate on a probing laser beam. RESULTS: No significant differences in average age, blood pressure, or intraocular pressure were observed between subjects with AMD and control subjects. In subjects with AMD, average ChBVol was 0.24 +/- 0.08 (+/- 1 SD) arbitrary units (AU); this value was 33% lower than that of control subjects (0.36 +/- 0.11 AU; two-tailed, independent Student's t-test, P = 0.005). Average ChBVel, conversely, was not significantly different from normal (0.44 +/- 0.07 AU) in subjects with AMD (0.44 +/- 0.10 AU). Average ChBFlow in subjects with AMD (8.7 +/- 3.1 AU) was 37% lower than that of control subjects (13.7 +/- 3.5 AU) (P = 0.0005). Average blood flow pulsatility was 6% higher in subjects with AMD (0.71 +/- 0.15) than in control subjects (0.66 +/- 0.14), but this difference was not statistically significant (P = 0.42). CONCLUSIONS: Average ChBFlow in the nonexudative stages of AMD is lower than that of age-matched controls, and the effect is caused mainly by a decrease in ChBVol. Further studies are needed to elucidate whether decreased ChBFlow plays a role in the development of choroidal neovascularization, and whether ChBFlow measurements may help identify subjects with AMD at risk for developing choroidal neovascularization.

Aged↗
PubMed1997

Occult choroidal neovascularization in age-related macular degeneration. A natural history study.

OBJECTIVE: To explore morphological and vision changes in untreated eyes with subfoveal choroidal neovascularization (CNV) that have poorly demarcated boundaries. DESIGN: Analysis of photographs of untreated patients with poorly demarcated occult CNV participating in a prospective clinical trial evaluating laser treatment compared with observation. SETTING: Two tertiary retinal referral centers. PATIENTS: Symptomatic individuals with poorly demarcated subfoveal occult CNV associated with age-related macular degeneration. MAIN OUTCOME MEASURES: Change in size of lesion, development of classic CNV, change in vision, and development of subretinal fibrosis. RESULTS: During follow-up (9-12 months), 32% of the occult choroidal neovascular lesions more than doubled their original size. Classic CNV developed in 52% of eyes that started without it. The median loss in visual acuity was 2.5 lines. Eyes with classic CNV or subretinal blood or both at baseline developed subretinal fibrosis more frequently and lost more visual acuity, but not to a statistically significant degree. CONCLUSIONS: The morphological changes of eyes with subfoveal occult CNV in which the boundaries are poorly demarcated in variable; the presence of subretinal blood or a component of classic CNV may influence the prognosis for further loss of vision.

Aged↗
PubMed1996

Macular scatter ('grid') laser treatment of poorly demarcated subfoveal choroidal neovascularization in age-related macular degeneration. Results of a randomized pilot trial.

OBJECTIVES: To determine the effects of macular scatter ("grid") laser photocoagulation compared with observation on the visual function of eyes with subfoveal choroidal neovascularization (CNV) that has poorly demarcated boundaries and to provide preliminary data for the evaluation of the feasibility and design of a larger, definitive trial. DESIGN: Randomized pilot clinical trial. SETTING: Two tertiary care retinal referral practices. PATIENTS: Symptomatic individuals with subfoveal CNV secondary to age-related macular degeneration in whom fluorescein angiography showed occult CNV with poorly demarcated boundaries; classic CNV was allowed but did not need to be present for entry into the study. MAIN OUTCOME MEASURE: Change in visual acuity from baseline to specified time periods. RESULTS: Fifty-two eyes were assigned to observation. Fifty-one eyes were assigned randomly to treatment consisting of macular scatter ("grid") laser photocoagulation to the area of CNV. The treatment protocol for 8 of these eyes also included confluent laser photocoagulation to areas of classic CNV. The average visual acuity decrease from baseline was greater in the treated than in the observed group. The difference between these groups was greatest within the first year after study enrollment. At 24 months, slightly more than 40% of the eyes in each group had lost 6 or more lines of visual acuity. Similar results were noted for the subgroup of eyes initially with angiographic features of occult CNV but no classic CNV. CONCLUSIONS: These short-term study results suggest that macular scatter ("grid") laser treatment is not beneficial and is possibly harmful compared with observation for symptomatic subfoveal CNV with poorly demarcated boundaries in age-related macular degeneration. With or without treatment, a significant proportion of these patients are at risk of severe visual loss within 2 years of seeking treatment, even when the eye initially has occult CNV and no classic CNV.

Aged↗
PubMed1994

Foveomacular dystrophy.

We reviewed the clinical records of 47 patients (92 eyes) at the Wilmer Institute in whom foveomacular dystrophy had been diagnosed between 1977 and 1990 to determine reasons for initial examination, long-term visual prognosis, and the factors associated with visual loss. From each clinical record, we obtained the patient's age at the time first seen, symptoms, initial and final visual acuity, lesion size and appearance, and results of fluorescein angiography, electroretinography, and electro-oculography. The most common reasons for examination were decreased visual acuity in 25 of the 47 patients (53%), metamorphopsia in six (13%), referral for diagnosis in seven (15%), and misdiagnosis of age-related macular degeneration in seven (15%). Over an average follow-up period of 5.0 years, in 29 patients (56 eyes), visual acuity changed less than two lines in 41 eyes and decreased greater than or equal to two lines in 15 eyes. In most patients with foveomacular dystrophy, visual acuity appears to remain relatively stable.

Adult↗
PubMed1994

Clinicopathologic correlation of drusen and retinal pigment epithelial abnormalities in age-related macular degeneration.

BACKGROUND: Clinicopathologic studies of eyes lead to a better understanding of the nature of the ophthalmoscopic and fluorescein angiographic features of drusen. A study was conducted to provide clinicopathologic correlation of drusen and present a classification of drusen based on clinical and histopathologic features. METHODS: The macular areas of three eyes from two patients were serially sectioned and studied, and features were depicted in a two-dimensional map and compared with clinical findings. RESULTS: All three tyes had large drusen (> 63 microns) with soft morphologic characteristics (poorly demarcated borders) documented on fundus photographs. In both eyes from one patient, these large drusen corresponded to areas of focal retinal pigment epithelium hypopigmentation overlying Bruch's membrane, which was diffusely thickened throughout the macula. Similar findings were noted in another eye from a second patient, and additionally, where there was relatively marked fluorescein staining of large drusen on the late phase of an angiogram, the pathologic correlation demonstrated detachment of the thickened inner aspect of Bruch's membrane from the remainder of Bruch's membrane. Focal hyperpigmentation corresponded to areas of hypertrophy of the retinal pigment epithelium and to clusters of pigmented cells in the subretinal space and outer nuclear area. CONCLUSION: Diffuse thickening of the inner aspect of Bruch's membrane is associated with retinal pigment epithelial hypopigmentation, focal atrophy, and soft (large) drusen formation.

Aged↗
PubMed1993

Central serous chorioretinopathy and pregnancy.

BACKGROUND AND OBJECTIVE: Fourteen cases of central serous chorioretinopathy in pregnancy had been reported before this study was conducted. These cases have suggested a nonwhite predominance. Subretinal fibrinous exudates have been seen in 90% of the patients, compared with fewer than 20% of patients in typical (nonpregnant) central serous chorioretinopathy. No case has recurred outside of pregnancy, to our knowledge, and there have been no reports of subsequent pregnancies uninvolved by this disorder. These findings led us to collect our cases of central serous retinopathy in pregnancy because our experience differed from that of previous reports and provides additional new information. DESIGN: Case series. SETTING: The Wilmer Institute Retinal Vascular Center, Baltimore, Md. PATIENTS: Questionnaires sent to retinal faculty and fellows and a review of files revealed four patients, all included herein, with central serous chorioretinopathy presenting during pregnancy. RESULTS: All four patients were white. Three patients had subretinal fibrinous exudates and/or precipitates. All experienced resolution of the serous detachment near the end of the pregnancy or within the first few months after delivery. Only one patient had a subsequent pregnancy, and this was not complicated by the presence of central serous chorioretinopathy. One other patient experienced a recurrence 2 1/2 years after her last pregnancy. CONCLUSIONS: There may be no racial predominance in the development of central serous chorioretinopathy in pregnancy. Subretinal fibrinous exudates are quite common, independent of race. The uninvolved subsequent pregnancy suggests that recurrence in the context of pregnancy is not inevitable. This disorder may recur outside of pregnancy.

Adult↗
PubMed1993

Visual abnormalities associated with high-energy microwave exposure.

A 44-year-old man was accidentally exposed to high-energy microwave irradiation. After resolution of facial erythema and iritis, he noted a foreign body sensation and blurring of vision. Ophthalmoscopic examination showed bilateral, small hard drusen. Ancillary tests were consistent with abnormal cone function. Electroretinogram testing revealed a marked decrease in the flicker electroretinogram. Results of D15 and Farnsworth Munsel Hue 100 color tests were abnormal. Two years later, the patient's visual acuity was stable at 20/25 in both eyes; however, results of flicker electroretinogram test remain markedly decreased.

Adult↗
PubMed1992

Observations on patients with idiopathic macular holes and cysts.

We reexamined 96 patients with macular holes or cysts. The mean follow-up period was 4.7 years. Of 19 eyes with macular cysts, only two (10.5%) showed progression to a macular hole. In 15 (79%) of those 19 eyes, the cyst disappeared. Of 80 patients with a macular hole or cyst in one eye and a normal fellow eye, a hole developed in the fellow eye in only one patient (1.2%) and a cyst developed in the fellow eye in only two patients (2.5%). Of 66 eyes with a stage 3 full-thickness macular hole, three eyes (5%) showed resolution without any sign of a hole. Our results suggest a favorable prognosis for normal fellow eyes of patients with macular holes or cysts and for eyes with cysts. Eyes with full-thickness macular holes have a less favorable prognosis, although their natural history may not be as poor as previously thought.

Adult↗