Biomedical subjects
Publications and source records attributed to T A Poole.
We developed a 20-gauge combination illumination-irrigation probe for use in pars plana vitrectomy. This instrument makes the vitrectomy procedure less traumatic and technically easier.
In a series of cataract patients excluding myopic individuals, under age 60 years, and cases in which vitreous loss occurred, retinal detachment was no less frequent after intracapsular cataract extraction and Sputnik iris supported lenses than in controls. Both groups were followed up for a minimum of two years. The detachments predominantly occurred from retinal breaks in areas of the retina that looked normal preoperatively.
We devised a new binocular indirect ophthalmoscope and a complimentary examination technique that provide enhanced fundus magnification and optimum stereopsis through a wide range of patient pupillary apertures. The lightweight, mechanically simple instrument uses a variable focus Galilean telescopic observation system to enlarge the condensing lens image of the fundus seen by the examiner. The present device is capable of about X 1.5 fundus magnification with negligible stereopsis through a 20-mm patient pupil, continuously increasing to X 8.5 with greatly enhanced stereopsis through an 8-mm pupil. A zoom focusing capability considerably extends the magnification, stereopsis, and small pupip penetrating characteristics of a given condensing lens by allowing the examiner to binocularly observe the telescopically magnified fundus image throughout the 30-cm to 60-cm focusing range of the ophthalmoscope.
A series of in vitro, in vivo, and clinical studies was performed to explore the safety and efficacy of argon laser and xenon arc photocoagulation in pseudophakia. The polymethylmethacrylate intracameral lens (Fyodorov) proved resistant to photothermal decomposition and allowed transmission of therapeutically effective energy levels to the retina. The argon laser delivered through a slit lamp and contact lens optical system appears to be the preferred method for posterior segment photocoagulation in pseudophakia. On the basis of five-day tissue culture studies and clinical experience of two years, the intracameral lens does not appear to be a toxic or transmission barrier to careful argon laser photocoagulation.
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Epinephrine maculopathy occurred in one eye of a patient that spontaneously developed intraretinal cystic maculopathy in the other eye. The clinical and fluorescein angiographic apperance of the two conditions were identical. It is likely that the two conditions have a common organic denominator.
Tension analysis along the retinal surface demonstrates the advantage of meridional buckles over limbal-parallel buckles. A cylindrical sponge generates tensional forces in the retina along the long axis of the buckle and perpendicular to it. The tension perpendicular to the sponge is positive, and the retina and retinal pigment epithelium stretch in that direction. The tension along the long axis is positive (stretching) when the buckle is less than 90 degrees arc length; and negative (compression), greater than 90 degrees for a 5-mm sponge. Consequently, retinal compression folds on the buckles occur for buckles of arc length greater than 90 degrees. These tension forces at right angles to each other explain the development of (1) concave retinal detachment or retinal folds off short limbal-parallel buckles, (2) retinal folds on long limbal-parallel buckles, and (3) fishmouthing of horseshoe tears overlying a limbal-parallel buckle. The buckle increases retinal surface area overlying the buckle. The significance of this is not clear, but it may explain the lessening or disappearance of compression folds on the buckle in time.