Anterior and posterior axial lens displacement and human aqueous outflow facility.

We studied the effect of anterior and posterior axial crystalline lens displacement (and thereby ciliary tone) on the aqueous humor outflow facility in enucleated human eyes. After attaching a reversible footplate plunger to the anterior lens capsule with cyanoacrylate, the lens was placed in one of three positions: "neutral baseline," posterior displacement (2.5 mm), or anterior displacement (2.0 mm). In seven pairs of eyes, the mean "neutral baseline" was not statistically different from the control eye, but anterior lens displacement decreased outflow facility "C" by 0.14 (36%) (P less than 0.0001), and posterior displacement increased "C" by 0.18 (50%) (P less than 0.01). Anterior or posterior lens displacement after complete ciliary body detachment produced no effect on outflow facility in two pairs. Histologic correlation studies demonstrated narrowing of the intertrabecular spaces and Schlemm's canal in the eyes fixed in anterior lens displacement, and widening of the same structures in the eyes fixed in posterior lens displacement. The lens-zonular-ciliotrabecular force vectors are responsible for the compression or decompression of the meshwork and Schlemm's canal in this model, with compression decreasing, and decompression increasing aqueous humor outflow facility.

Pupillary block with posterior chamber intraocular lenses.

We present 12 cases of pupillary block associated with extracapsular cataract extraction and posterior chamber intraocular lenses. In one case, pupillary block occurred despite the presence of a surgical iridectomy. The other 11 patients did not have a surgical iridectomy performed. We recommend that a surgical iridectomy or laser iridotomy be performed in all patients who undergo extracapsular cataract extraction with the implantation of posterior chamber intraocular lenses. Ophthalmologists need to be vigilant in watching for the development of pupillary block in these patients, since pupillary block is not a benign event and serious visual loss or disability may occur.

The Slate turkey: a model for secondary angle closure glaucoma.

An inherited eye disease leading to a secondary angle closure glaucoma has been observed in turkeys (Meleagris gallapavo) of the Slate variety. The initial indications of the disease involve a low grade aqueous cell and flare reaction, associated with progressive posterior synechiae formation resulting in pupillary block and iris bombé. A midperipheral iridocorneal adhesion follows, accompanied by corneal edema, breaks in Descemet's membrane, and buphthalmos. IOP is not elevated substantially until a complete iris bombé occurs. Expression of the defect is sex-influenced, with females exhibiting the most severe pathological changes.

Argon laser trabeculoplasty. Studies of mechanism of action.

The effects of argon laser trabeculoplasty (LTP) on outflow facility, Schlemm's canal morphology, trabecular cellularity, and trabecular glycosaminoglycan composition were determined in 33 pairs of eye-bank human eyes. At two levels of intraocular pressure, measured outflow facility did not immediately drop in response to LTP. Schlemm's canal distention was observed only at 40 mmHg intraocular pressure, where the canal normally tends to collapse. Trabecular cell density was reduced by about 40% in the eyes receiving laser treatment. The organ cultured trabecular meshworks in response to LTP altered their incorporation of 35S-sulfate, compared to controls, suggesting a change in the synthesis or turnover of the extracellular matrix of the trabeculum after trabeculoplasty. At least three potential mechanisms were identified in response to laser trabeculoplasty, including some mechanical distortion of the trabeculum at high intraocular pressures. We also hypothesize that laser trabeculoplasty dislodges some trabecular cells and may stimulate the remaining cells to renew more active synthesis and/or turnover of the trabecular extracellular matrix.

Dipetalonema from the eye of a man in Oregon, U.S.A. A case report.

A 21-mm filarial worm appeared suddenly in the anterior chamber of the right eye of a 32-year-old man in western Oregon. By a simultaneous irrigation-aspiration procedure, it was removed alive and only slightly damaged and was identified as a female Dipetalonema in the fourth stage of development. It was the third such case to be reported from western Oregon. In this and one other case the worms were morphologically similar to adult worms identified as Dipetalonema arbuta Highby 1943 from the body cavity of the porcupine (Erethizon dorsatum) and a similar species, Dipetalonema sprenti Anderson 1953, from the body cavity of the beaver (Castor canadensis).

Tactile litholapaxy--safe and efficient.

Tactile litholapaxy is a safe procedure and is not difficult to learn. It can be used for stones up to 5 cm. in diameter unless the stone is very hard. The bladder is distended with irrigating fluid, the lithotrite passed, the jaws opened, and the lower jaw depressed against the floor of the bladder and vibrated to allow the stone to roll on to it. The upper jaw is depressed against the stone, the threads at the handle are meshed, and the stone is crushed. Fragments are crushed in like manner and are then washed out through a resectoscope sheath. It is easier to do and more efficient in both length of operating time, absence of complications, and shorter hospital stay when compared with visual litholapaxy and cystolithotomy.