Atropine inhibition of echothiophate cataractogenesis in monkeys

One cynomolgus and three vervet monkeys were treated topicall twice daily in one eye with 63 microgram of echothiophate iodide and 750 microgram of atropine sulfate. The opposite eyes were treated with echothiophate alone. The eyes treated with echothiophate alone all developed posterior and/or anterior subcapsular cataracts within 26 to 66 days. The echothiophate plus atropine-treated cynomolgus eye developed a cataracts of much delayed onset and lesser severity compared to its echothiophate-only-treated fellow. None of the echothiophate plus atropine-treated vervet eyes developed cataracts during the 121 (two eyes) or 231 (one eye) days of treatment. After 121 days of echothiophate plus atropine treatment, two vervet eyes were switched to echothiophate alone. Both eyes developed unequivocal posterior and anterior subcapsular lens opacities, one within 51 and one within 71 days after the switch. We conclude that atropine inhibits echothiophate cataracto-genesis in vervet and cynomolgus monkeys.

Induction of subcapsular cataracts in cynomolgus monkeys by echothiophate

Sixteen eyes of 13 cynomolgus monkeys were treated topically twice daily with echothiophate iodide. The dosages were increased gradually over several weeks to plateau levels ranging from 125 to 500 mug daily. The opposite eyes of the ten unilaterally treated monkeys received a control solution (DILUENT) identical save for the absence of echothiophate. All 16 echothiophate-treated eyes developed posterior subcapsular cataracts and 15 developed anterior subcapsular cataracts. The lenses in all ten DILUENT-treated eyes remained clear. The cataracts in the echothiophate-treated eyes strongly resembled those attributed to cholinesterase inhibitors in humans. They were first noted from 2 1/2 to 14 weeks after beginning echothiophate treatment. Prior total iridectomy caused a more rapid progression and/or greater severity of lens changes. Higher echothiophate dosages caused the cataracts to appear more rapidly.

Light and electron microscopy of the anterior chamber angle structures following surgical disinsertion of the ciliary muscle in the cynomolgus monkey

Light and electron microscopic studies were done on 11 cynomolgus monkey eyes which had undergone total iris removal followed by surgical disinsertion of the ciliary muscle from the scleral spur 4.7 to 14.4 months earlier. Anterior chamber perfusion to measure gross outflow facility had been performed one to nine times postoperatively. Over most of the circumference in most eyes (1) the ciliary muscle had been retrodisplaced from the scleral spur and had reattached to the sclera more posteriorly; (2) ciliary muscle, trabecular meshwork, and Schlemm's canal appeared normal. A cyclodialysis cleft was never seen. Fixation of some eyes in the in vivo and in vitro presence of pilocarpine demonstrated the contractibility of the retrodisplaced muscle. In isolated areas where the ciliary body had been surgically cut, scar tissue of varying thickness connected scleral spur, sclera, ciliary body, zonule, and lens capsule, but did not infiltrate trabecular meshwork or Schlemm's canal. In such sectors, plasma cell-like cells replaced trabecular endothelial cells and were also present in the scar tissue, ciliary muscle, and surrounding vessel walls in the scar and sclera. In sectors of two eyes, a previously existing trabecular operculum extended posteriorly and completely covered the meshwork. The meshwork in these sectors was poorly perfused by aqueous humor, and electron-dense deposits were present beneath the inner wall of Schlemm's canal. Four totally iridectomized and two unoperated eyes from these monkeys were also examined; ciliary muscle, trabecular meshwork, and Schlemm's canal appeared normal in all, despite the numerous anterior chamber perfusions.

Formation and drainage of aqueous humor following total iris removal and ciliary muscle disinsertion in the cynomolgus monkey

Aqueous humor formation (AHF), uveoscleral flow (U), gross outflow facility (Cg), true facility of outflow from the anterior chamber (Ct1), true facility of outflow from anterior chamber into the general circulation (Ct2), and the pressure sensitivity of AHF (pseudofacility; Cps) were determined in cynomologus monkey eyes which had undergone total iris removal or iris removal followed by ciliary muscle disinsertion. AHF was in the normal range in iridectomized-only eyes. AHF was present but reduced in "disinserted" eyes. U was markedly reduced and similar in both types of eyes. Cps was normal and Cg, Ct1, and Ct2 were low in "disinserted" eyes. Cg, Ct1, and Ct2 were nearly equal in the "disinserted" eyes, indicating that gross facility consisted almost entirely of pressure-dependent flow from anterior chamber into the general circulation, presumably via the conventional drainage routes.

Cytochalasin B reversibly increases outflow facility in the eye of the cynomolgus monkey

In cynomolgus monkeys, intracameral infusion of 0.2 to 5.0 mug of cytochalasin B caused an increase in outflow facility, as measured by two-level constant pressure perfusion. Cytochalasin B had its full effect in eyes which had undergone surgical disinsertion of the ciliary muscle from the scleral spur, and were therefore insensitive to pilocarpine. The cytochalasin effect was apparent in less than 20 min. and was largely reversible over a few hours. Thirty to 50 days after the infusion, facility was normal, and a second reaction could be elicited. No early or late damage to anterior segment structures was apparent by routine biomicroscopy during or after the single administration.

Subsensitivity to pilocarpine of the aqueous outflow system in monkey eyes after topical anticholinesterase treatment

Cynomolgus and vervet monkeys were treated unilaterally with topical echothiophate iodide twice daily for eight to 25 weeks. The effect of intracameral pilocarpine on outflow facility was determined in the ganglionic-blocked animal during and after echothiophate treatment. The echothiophate-treated eyes demonstrated marked subsensitivity to pilocarpine, and required several weeks to months to recover normal pilocarpine sensitivity.

Loss of acute pilocarpine effect on outflow facility following surgical disinsertion and retrodisplacement of the ciliary muscle from the scleral spur in the cynomolgus monkey

An ab-interno goniotomy-like operation for disinserting the ciliary muscle from the scleral spur in cynomolgus monkeys is described. Following postoperative miotic and corticosteroid treatment, the eyes did well clinically and the muscle reattached to the sclera posterior to the spur. Outflow facility and intraocular pressure were mildly reduced. There was drainage of aqueous humor via the conventional outflow routes, and blood flow to the ciliary body. The outflow facility increasing effect of intravenous and intracameral pilocarpine was nearly completely eliminated. These and other data suggest that: (1) the ciliary muscle was permanently disconnected, anatomically and functionally, from the trabecular meshwork; (2) the trabecular meshwork and Schlemm's canal remained relatively normal structurally and functionally; (3) monkey eyes with retrodisplaced ciliary muscles may prove valuable for testing the functional effects of drugs directly on the conventional outflow channels, independent of drug actions on the ciliary muscle.

Residual pilocarpine effects on outflow facility after ciliary muscle disinsertion in the synomolgus monkey

Outflow facility responses to pilocarpine were determined in ten cynomolgus monkey eyes after disinsertion of the ciliary muscle from the scleral spur. The effect of large intravenous dose given on one occasion was compared to the effect of intense topical treatment for 18 to 24 hours on another occasion. The effect of the two modes of treatment differed from eye to eye, but were similar in the individual eye. In some eyes facility rose while in others it fell. The average effect of both treatments was very small.

Prognosis of primary rhegmatogenous retinal detachments. 2. Accounting for and predicting final visual acuity in surgically reattached cases

Multiple linear regression-analysis of variance was used to define relationships between final visual acuity and several parameters in 31 patients with reattached primary rhegmatogenous retinal detachments. Older patient age, preoperative macular detachment, clinically visible macular lesions, greater detachment duration and extent, and higher subretinal fluid butyrylcholinesterase activity were all inversely related to final acuity. The relationship of each parameter to final acuity, in conjunction with and apart from all the other parameters, was defined. Collectively the parameters accounted for 85% of the variation about the mean of the clinically observed finally acuities. The parameters could be weighted to give a generally, reasonably accurate prediction of final acuity at the time of surgery. The findings are consistent with a pathophysiological sequence involving alterations in the choroidal circulation and the blood-ocular barrier of the posterior segment.

Induction of subcapsular cataracts in aniridic vervet monkeys by echothiophate

Four surgically aniridic vervet monkeys with clear lenses received topical echothiophate iodide unilaterally daily for eight weeks. The opposite eyes received a control solution without echothiophate. All the echothiophate-treated eyes developed subcapsular lens opacities sttongly resembling those attributed to echothiophate in humans. The lenses in the control eyes remained clear.

Total iridectomy in the primate in vivo: surgical technique and postoperative anatomy

A simple, brief surgical procedure for in vivo removal of the entire primate iris is described. A small peripheral corneal incision is made, and the prolapsed iris is torn from its insertion by forceps, without intraocular instrumentation. The eye recovers quickly and, except for the aniridia, the clinical and histologic appearance of the anterior segment is essentially normal. Experimental uses for the aniridic monkey eye are noted.

Prognosis of primary rhegmatogenous retinal detachments. 1. Associations between clinical detachment characteristics, subretinal fluid butyrylcholinesterase and visual outcome following scleral buckling procedures

Thirty-five patients with primary rhegmatogenous retinal detachments were followed for at least 6 months after scleral buckling procedures with subretinal fluid (SRF) drainage, in order to define factors influencing anatomic and visual outcome. Thirty-two cases were surgically reattached; three were not. Among the reattached cases, final visual acuity was poorer in patients with: older age; longer standing, more extensive detachments; detachment of the macula (with or without the development of a visible macular lesion); macular lesions; and higher SRF butyrylcholinesterase activity. These factors were themselves interrelated. Follow-up duration was only weakly related to final acuity, probably because of the long post-surgical follow-up. Phakic/aphakic status bore little relationship to final acuity. The type or timing relative to drainage of inflammation producing treatment was not related to final acuity.

Ocular findings and corticosteroid responsiveness in parents of children with primary infantile glaucoma

Aqueous humor dynamics, visual fields, optic discs, anterior chamber angles, and topical cortidosteroid responsiveness were studied in twenty parents of children having primary congenital glaucoma. The findings indicate that parents of children with primary congenital glaucoma resemble the general population with respect to the parameters tested, and do not resemble close relatives of patients with primary open-angle glaucoma.