Spectacle-mounted prisms as an aid in face-down positioning after vitrectomy surgery.

PURPOSE: To report a modification in the design of bed spectacles to provide an aid for patients who undergo face-down positioning after vitrectomy with gas-fluid exchange and postoperative gas tamponade. METHODS: New equipment design. Bed spectacles that use prisms to move the image 90 degrees around the horizontal meridian were modified by rotating the prisms in the frame 180 degrees and adding nosepads and cable temples. The spectacles were given to 12 patients for use during postoperative face-down positioning. A questionnaire was used to evaluate the helpfulness of the spectacles during face-down positioning. RESULTS: Patients ranked the spectacles as "helpful" to "very helpful" with a mean and SD of 8.3+/-1.6 on a scale of 1 to 10, where 1 was "a hindrance" and 10 was "very helpful." Patients wore the spectacles an average of 5.7+/-4.5 hours a day (range, 1.5 to 15 hours). CONCLUSION: Modified bed spectacles appear to be a portable aid to patients who undergo face-down positioning while sitting, standing, or prone.

Visual field loss caused by retinal vascular occlusion after vitrectomy surgery.

PURPOSE: To report complete superonasal retinal arterial occlusion with resulting temporal visual field loss after uneventful pars plana vitrectomy with gas-fluid exchange. METHOD: Case report. RESULTS: Superonasal retinal arterial occlusion was observed 12 days after vitrectomy surgery. Within 10 weeks, the artery reperfused, leaving minimal vascular attenuation and mild optic atrophy. CONCLUSIONS: Uneventful vitrectomy surgery can be associated with notable peripheral visual field loss caused by arterial occlusion in the immediate postoperative period. Rapid resorption of the intraocular gas and timely postoperative examination may disclose retinal arteriolar occlusion; otherwise, subsequent reperfusion may leave little evidence of the vascular event.

Familial exudative vitreoretinopathy associated with nonneovascular chronic angle-closure glaucoma.

PURPOSE: Cases of angle-closure glaucoma in patients with familial exudative vitreoretinopathy have been reported secondary to neovascularization of the anterior segment. Cases secondary to nonneovascular mechanisms have not been previously reported. METHODS: Two cases are presented of angle-closure glaucoma as a result of a nonneovascular mechanism. RESULTS: Neovascularization was found to be a very unlikely explanation for the angle closure in these two cases. CONCLUSION: There may be an association between familial exudative vitreoretinopathy and angle-closure glaucoma as a direct result of a retrolental process or more likely a relative lens-iris pupillary block with a large lens.

Surgical management of subfoveal choroidal neovascularization.

BACKGROUND: Subfoveal choroidal neovascularization (CNV) usually is associated with a poor visual prognosis. Laser photocoagulation of certain subfoveal membranes secondary to age-related macular degeneration (ARMD) appears preferable to observation based on recent Macular Photocoagulation Study (MPS) findings but is associated with decreased vision. The authors explored the use of vitreoretinal surgical techniques as an alternative method of eradicating subfoveal CNV. METHODS: After vitrectomy, a small retinotomy technique was used to extract or disconnect from the choroidal circulation subfoveal CNV in 58 eyes. There were 33 eyes with ARMD, 20 eyes with presumed ocular histoplasmosis, and 5 eyes with miscellaneous etiologies. Five eyes also received subfoveal RPE patches. RESULTS: With limited follow-up, significant improvement in vision (defined as 2 Snellen lines) was achieved in 7 of 22 eyes with ARMD CNV removal (1 eye 20/20), 0 of 4 eyes with ARMD CNV removal and RPE patches, and 1 of 7 eyes with ARMD CNV disconnection. Significant improvement was achieved in 6 of 16 eyes with presumed ocular histoplasmosis removal and 0 of 4 eyes with presumed ocular histoplasmosis CNV disconnection. In 5 eyes with miscellaneous CNV, 2 improved (20/20 and 20/40). CNV recurred in 29%. CONCLUSIONS: Some patients with subfoveal CNV appear to benefit from surgical removal. Only rarely do eyes with ARMD improve. Longer-term follow-up and refined case selection are required before this approach can be widely recommended.

Management of late-onset angle-closure glaucoma associated with retinopathy of prematurity.

Late-onset angle-closure glaucoma secondary to retinopathy of prematurity (ROP) occurred in ten eyes of ten patients. The age at presentation ranged from 12 to 45 years (mean, 32 years). Eight eyes had nonneovascular mechanisms for the angle closure while two had neovascular angle closure. Treatment of eyes with this form of secondary angle closure included medical management alone, peripheral iridectomy, trabeculectomy, lensectomy, alloplastic tube shunt implantation, and cilioablative procedures. Three eyes required more than one of these treatments. The choice of therapy was based on the initial intraocular pressure and vision, degree of lens opacity and intumescence, presence of anterior segment neovascularization, and the gonioscopic appearance of the anterior chamber angle. The clinical features of this condition are described and a proposed mechanism and therapeutic approach are presented.

Vitrectomy for premacular fibroplasia. Prognostic factors, long-term follow-up, and time course of visual improvement.

Two hundred seventy eyes with premacular fibroplasia consecutively treated by pars plana vitrectomy and membrane peeling were reviewed. This study is among the largest series with long-term follow-up reported to date. Visual improvement of two or more lines was achieved in 43% of eyes at 6 to 12 months, in 54% at 1 to 2 years, in 60% at 2 to 3 years, and in 58% at 3 to 5 years. Overall, complications occurred in 34 eyes (13%). Cataract progression after vitrectomy was noted in 106 (57%) of phakic eyes at 3 to 5 years, and 43 of these eyes underwent subsequent cataract extraction. Mean time to best visual acuity after vitrectomy was slightly less than 1 year for all eyes unless they had cataract worsening with subsequent cataract extraction (1.9 years). Significant factors affecting visual outcome were: preoperative lens status, visual acuity before vitrectomy, duration of preoperative symptoms of distortion and/or blurred vision, and the occurrence of intraoperative complications.

Acute angle-closure glaucoma from spontaneous massive hemorrhagic retinal or choroidal detachment. An updated diagnostic and therapeutic approach.

Acute angle-closure glaucoma from a spontaneous massive hemorrhagic retinal or choroidal detachment occurred in five eyes. The source of the hemorrhagic detachment was a disciform macular lesion in all instances. The mechanism for the angle closure is the abrupt forward displacement of the lens-iris diaphragm resulting from the massively detached choroid and retina. Four of the five patients had either systemic hypertension or a primary or anticoagulant-induced clotting disorder. All patients underwent ultrasonographic studies, and one patient had magnetic resonance imaging (MRI) to rule out melanoma. Only one eye required enucleation for pain relief. Glaucoma medication, cyclophotocoagulation, or retrobulbar alcohol controlled the other four eyes. The clinical, ultrasonographic, MRI, and histopathologic features of this rare condition are described, and an updated therapeutic approach is discussed.

Seven cases of trilateral retinoblastoma.

Of 245 consecutive children with retinoblastoma referred to the Oncology Service at the Wills Eye Hospital between January 1974 and August 1988 and followed up for three months to 15 years, seven (3%) developed midline intracranial malignancies consistent with the diagnosis of trilateral retinoblastoma. Six of the seven had bilateral retinoblastoma, and four had a family history of retinoblastoma. The time of diagnosis of retinoblastoma varied between five months after the intracranial tumor was diagnosed and four years before the intracranial tumor was diagnosed. The midline intracranial malignancies were pineal tumors (five cases), suprasellar neuroblastoma (one case), and a parasellar undifferentiated calcified mass (one case). Despite control of the intraocular tumors, five of the seven children have died of the intracranial tumors.

Acetylcholine concentration and its role in ionic transport by the corneal epithelium.

Corneal epithelium is known to have a high acetylcholine (ACh) concentration, but its role remains uncertain. Furthermore, rabbit corneal epithelium is devoid of cholinergic receptors. ACh concentration in calf, rabbit, and frog corneal epithelium was determined with Fellman's fluorometric assay to be 16.9, 11.1, and 21.8 micrograms of ACh per gram of epithelium, respectively. The isolated frog cornea was used to examine a possible role of the cholinergic system on active ionic transport. A 2 mM concentration of exogenous ACh has a moderate inhibitory effect on Na transport but no effect on Cl transport. A 10(-4)M concentration of 4-(1-naphthylvinyl) pyridine (NVP), a choline acetyltransferase inhibitor, reversibly inhibited both Na and Cl transport by about 70%. NVP also reduced ACh content of frog corneal epithelium by 51%. Thus endogenous ACh, but not exogenous ACh, seems to be stimulatory of active ionic transport. Of several muscarinic or nicotinic blockers tested, 10(-3)M atropine inhibited Na transport by 55% and Cl transport by 83%; 10(-3)M nicotine inhibited Na transport by 33% and Cl transport by 17%. If frog cornea (like rabbit cornea) contains no cholinergic receptors, the effects of ACh, nicotine, and atropine on ionic transport may be mediated through a nonspecific pathway.

Na+ and Cl- fluxes, and effects of pharmacological agents on the short-circuit current of the isolated rabbit iris-ciliary body.

Unidirectional Na+ and Cl- fluxes were measured across the isolated rabbit iris-ciliary body under short-circuited conditions. Na+ fluxes were in the range of 9-13 mueq/hr X cm2, and Cl- fluxes varied between 7-12 mueq/hr X cm2. A statistically significant net Na+ or Cl- flux could not be found. Ouabain, 5X10(-5) M, did not change the Na+ or Cl- flux in either direction despite a marked effect on the short-circuit current (SCC). There was a disagreement between the electrical conductance calculated from unidirectional fluxes and electrical measurements, suggesting the presence of electrically silent exchange mechanisms. Theophylline and isobutyl methylxanthine stimulated the SCC, whereas epinephrine, trifluormethazolamide and diisothiocyanostilbene disulfonic acid inhibited the SCC. Furosemide had a minor inhibitory effect, and the Ca2+ ionophore A23187 was without effect. Amphotericin B produced a substantial stimulation of the SCC from the aqueous side but an inhibition of the SCC from the blood side. This dual effect is consistent with the presence of Na+ -K+ pumps in the basolateral membranes of both the pigmented and non-pigmented cell layers of the ciliary body.