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Systemic findings in a 23-year-old white man with mucolipidosis type IV included early delayed psychomotor development, mental retardation, and mild facial dysplasia. There was urinary excretion of chondroitin sulfate. Ophthalmologic examination showed corneal haze, pigmentary retinopathy, and severe optic atrophy. Light microscopy showed massively engorged superficial and intermediate epithelial cells of both the cornea and the conjunctiva. By transmission electron microscopy these contained fine granular material consistent with acid mucopolysaccharide and concentric lamellar bodies presumably representing phospholipids. This storage phenomenon was also found in macrophages, plasma cells, ciliary epithelial cells, Schwann cells, retinal ganglion cells, and vascular endothelial cells. Light microscopy also disclosed early cataract formation, marked outer retinal degeneration, and optic atrophy.

A retrospective review of 68 consecutive episodes of microbial keratitis complicating 66 penetrating keratoplasties (PKs) showed major risk associations: suture-related problems (50%), contact lens wear (26%), previous herpes simplex infection (15%), graft failure (15%), and persistent epithelial defects (15%). Topical steroid (85%) and antibiotic (59%) usage were common iatrogenic factors. Half the infections occurred more than 1 year after grafting. Bacterial infections involving gram-positive organisms (59%) predominated, except for patients with extended-wear hydrophilic contact lenses, which usually involved gram-negative bacilli. The incidence of fungal infections (6%) was relatively low. Recommendations to minimize microbial keratitis include prompt attention to exposed, broken, or loose sutures, and preventive and therapeutic management of epithelial defects. The inadequacy of low-dose antibiotics in precluding microbial infection in many cases and the propensity to develop infections with resistant organisms suggest that guidelines for using postoperative and prophylactic topical antibiotics require reevaluation.

Superior limbic keratoconjunctivitis (SLK) is a chronic and recurrent inflammatory disease of the superior tarsal, bulbar and limbal conjunctiva that often responds to topical treatment with silver nitrate. As an alternative treatment in 11 patients (13 eyes), we applied thermal cautery to the inflamed superior bulbar conjunctiva following subconjunctival injection of 2% xylocaine. The overall positive response rate to thermocautery was 73% (8 patients). Of the positive responders, 63% (5 patients) had been considered silver nitrate treatment failures. Keratitis sicca was additionally noted in 55% of the patients studied. Impression cytology of involved superior bulbar conjunctiva was nearly devoid of goblet cells during the acute stage of the disorder. Following successful cauterization, goblet cells returned. Thus, thermocauterization of the superior bulbar conjunctiva appears to be a safe and effective mode of therapy for SLK.

The clinicopathologic features of Chandler's syndrome are elucidated based on a study of nine patients. Keratoplasty, trabeculectomy and/or iris specimens were studied by light, electron and, in six cases, specular microscopy. The prominent pathologic features were abnormalities of the endothelially-derived cells lining the posterior corneal surface, the inner surface of the trabecular meshwork, and the anterior iris surface. In all four corneal buttons, the endothelium was diffusely attenuated and focally absent, and posterior collagen layers were present. Extension of the endothelial cell layer and Descemet's membrane deposition over the trabecular meshwork were observed in two trabeculectomy specimens, and similar proliferation onto the anterior surface of the iris was evident in four iris specimens. Other abnormalities of the endothelial cells included increased intracytoplasmic filaments. These pathologic alterations are consistent with the concept of Chandler's syndrome as representing one variant of the iridocorneal endothelial (ICE) syndrome. Interestingly, although both endothelial proliferative and degenerative responses can be observed in Chandler's syndrome, their occurrence within the same eye is apparently not simultaneous.

To secure a penetrating keratoplasty donor button, a continuous suture is both less time consuming to place and easier to remove. Infrequently, however, the continuous suture may loosen or break prematurely. For this purpose we propose the anchor suture as a simple technique to restore a tight, continuous suture and a secure wound.

The biochemistry of contact lens-cornea interaction is not well understood, although previous studies have suggested that corneal metabolic changes may be the underlying factor in morphological alterations. Using a rabbit model, this interaction has been examined with 31P nuclear magnetic resonance (NMR) spectroscopy, which detects signals principally from the epithelium. The examination was supplemented with electron microscopy and histochemistry. Polymethylmethacrylate lenses caused reversible changes, including activation of anaerobic glycolysis and disturbance of membrane metabolite levels. These changes were far more severe than those occurring during prolonged eye closure. There appears to be an association between cellular deterioration and loss of membrane metabolites. On the other hand, oxygen-permeable silicone lenses allowed maintenance of nearly normal metabolic patterns. These results show multifaceted corneal response to hard contact lens wear.

In a 35-year-old patient with keratoconus a cyst of the iris was first observed 22 months after routine penetrating keratoplasty. The lesion was completely excised and shown by light and transmission electron microscopy to be composed of conjunctival epithelium organised as a single large cyst containing serous material and occasional free epithelial cells. The management of epithelial implantation cysts is discussed. When indicated, complete surgical excision without ruputure is preferred to avoid possible intraocular dissemination of viable epithelial cells that might result in further complications.

Corneal tissue from five eyes of three children with active xerophthalmic keratopathy and stromal loss was studied histopathologically. Stromal dissolution was strikingly focal, sometimes occurring beneath an intact epithelium and often, though not always, accompanied by extensive inflammatory reaction and bacteria.

Corneal buttons from three patients with congenital central corneal leukoma (Peters' anomaly) were examined by light and electron microscopy. All cases exhibited a central absence of Bowman's membrane and iris synechiae to the periphery of the leukoma. In the first patient, extensive keratolenticular adhesion with retrocorneal fibrous tissue filling the central defect of endothelium and Descemet's membrane implicated late anterior displacement of the normally developed lens as the cause of secondary endothelial degeneration. In the second patient, attenuated endothelium and abnormally composed Descemet's membrane indicated primary dysgenesis of the endothelium. In the third patient, the extensive defect of posterior stroma with anterior stromal disorganization and endothelial metaplasia suggested dysgenesis of both the keratocytic and endothelial mesoderm. Thus, although no unified pathogenic mechanism was consistently applicable, either primary or secondary dysgenesis of the corneal mesoderm must be responsible.

The technique and results of conjunctival autograft transplantation for advanced and recurrent pterygium are presented for 57 eyes of 54 patients. The pterygia were primary in 16 eyes and recurrent in 41; among the latter group, 14 patients had diplopia resulting from cicatricial involvement of the medial rectus muscle. In all cases, free conjunctival grafts from the superotemporal bulbar conjunctiva of the same eye were used to resurface exposed sclera and extraocular muscle. There were no intraoperative complications. Postoperative follow-up ranges from 1 to 67 months, with a mean of 24 months. Only three pterygia have recurred (5.3%); two were successfully remedied by a second conjunctival autograft, whereas the third did not require an additional procedure. In all 14 patients with diplopia, extraocular movement was restored. We recommend this surgical approach as a safe and effective means of treating pterygia complicated by conjunctival scarring with extraocular muscle involvement and requiring concurrent fornix reconstruction.

Total ocular-surface alkali burning was performed on guinea pigs to study the effects of generalized immunosuppression and selective inflammatory cell line modifications on corneal ulceration. Central stromal corneal ulceration developed in 86% (18/21) of control eyes three to seven days after alkali burning, whereas ulcers developed in only 16% (3/19) of the eyes of guinea pigs immunosuppressed with cyclophosphamide. Neutrophils, the preponderant inflammatory cells in ulcerating corneas, were conspicuously absent from the nonulcerating corneas. Selective neutrophil suppression by intravenous administration of a highly specific anti-guinea pig neutrophil serum also suppressed the development of corneal ulcerations in this model; in only 25% of the eyes so treated did ulcers develop after alkali burning. T lymphocyte or monocyte modifications with similar monospecific antisera had no effects on the rate of corneal ulceration. Neutrophil depletion after the onset of ulceration halted progression of the corneal ulcer.

The authors studied the histopathologic, ultrastructural, and immunopathologic characteristics of conjunctiva from patients with Stevens-Johnson syndrome (SJS). A small subset of SJS patients with recurrent conjunctival inflammation unassociated with external factors such as lid margin keratinization, sicca syndrome, trichiasis, or entropion was identified. The ultrastructural and immunopathologic characteristics of the conjunctiva from these patients were distinctly different from those of the conjunctiva from SJS patients without recurrent conjunctivitis, and suggested an active, immunologically mediated inflammation. Vasculitis or perivasculitis, immunoreactant deposition in vessel walls, vascular basement membrane disruption, thickening, and reduplication, and a preponderance of helper T-lymphocytes, macrophages, and Langerhans' cells were the notable distinguishing features in those patients with recurrent conjunctival inflammation. This rare clinical syndrome may represent the ocular counterpart to recurrent dermal or oral mucosal erythema multiforme.

Pigmentation of the posterior corneal surface results either from endothelial phagocytosis of free melanin pigment or from the presence of iris melanocytes, iris pigment epithelial cells, or pigment-containing macrophages on the posterior corneal surface. Although this is occasionally seen clinically, it is more often noted at histopathologic evaluation after operative or accidental ocular trauma. Three cases of posterior corneal pigmentation by iris melanocytes are reported. In one case, the pigmented membrane was the major cause of considerable visual impairment and was documented with clinical photographs and specular microscopy. By light and electron microscopy, all three cases were consistent with findings of posterior corneal pigmentation by iris stromal melanocytes that had acquired endothelium-like morphologic characteristics. We also consider the possible contribution of these melanocytes to posterior collagen layers of the cornea.

The authors studied prospectively 59 eyes with corneal edema after cataract surgery that required reconstructive surgery; penetrating keratoplasty in 59 (100%), anterior vitrectomy in 42 (71%), intraocular lens removal or exchange in 33 (56%), gonioplasty in 32 (54%), and iridoplasty in 30 (51%). With an average follow-up of 9.9 months, the corneal transplant was clear in 56 eyes (95%). The corrected visual acuity was improved in 49 eyes (83%) and was the same in seven eyes (12%). Intraocular pressure was less than or equal to 21 mmHg in 47 eyes (80%) and 22 to 29 mmHg in nine eyes (15%). The peripheral anterior synechiae score was the same or improved in 56 eyes (95%). Cystoid macular edema was absent to mild in 52 eyes (88%). Anterior segment reconstruction improved both anatomic integrity and visual acuity of most eyes without increasing complications.

A 62-year-old white woman with hypertensive diabetes had central retinal artery occlusion of her right eye. Serial electroretinographic (ERG) studies demonstrated reversible changes in the scotopic components but permanent reduction of the photopic b-wave. Serial simultaneous fluorescein and indocyanine green angiographic studies demonstrated a perfusion defect in the choroid involving part of the macula which subsided after reopening the retinal circulation. Differential hypoxic susceptibility of the ERG photopic and scotopic b-waves was demonstrated, and changes in the patient's retinal tissue oxygenation were postulated on the basis of retinal and choroidal angiographic studies performed during and after central retinal artery occlusion to account for the observed changes in serial ERGS.

The corneas of three patients with keratoconus were examined by light and electron microscopy within approximately four months after onset of severe hydrops. The rupture and detachment of Descemet's membrane resulted in formation of extensive ledges. New endothelium completely resurfaced the exposed posterior stroma and the corresponding anterior aspect of the ledges. The endothelium also regenerated considerable basement membrane. In one case, clustered endothelium near the free end of the ledge appeared to have undergone fibrous metaplasia with secretion of extensive fibrillar and basement membrane material.

Transforming growth factor-beta (TGF-beta) is a multifunctional peptide that modulates cell proliferation and differentiation in many cell types and accelerates tissue repair response. In this study, expression of TGF-beta was investigated immunohistochemically in the healing of central 3 mm epithelial wounds of vitamin A-deficient (A-) rat and pair-fed controls. In control rat corneas, a positive reaction to TGF-beta was not evident during wound healing. In A- rat corneas at 4 hr post-abrasion, acute inflammatory cells showing high positivity to TGF-beta appeared in the peripheral stroma and gradually spread to the central cornea. By 24 hr, these cells accumulated and formed a pseudomembrane in the epithelial defect, which also showed an intense positivity to TGF-beta, suggesting that the peptide participates even in the acute inflammatory response. From about 16 hr post-injury, many fibroblasts revealing intense positivity to TGF-beta infiltrated the entire stroma and were part of the healing process. Reepithelialization occurred over the pseudomembrane and was completed by 48 hr. The central cornea showed remodeling of collagen structure and neovascularization. Fibroblasts containing TGF-beta were seen in the stroma, indicating that TGF-beta plays an important role in corneal wound healing. Indeed, in the absence of vitamin A, a common modulator of cell differentiation, TGF-beta may play a more important role in wound healing than in the normal state.

This animal study of corneal surface injury using acid, alkali n-heptanol, iodine, keratectomy, or scraping, despite morphologic differences from the human, simulated the human response to these forms of trauma. The rabbit and monkey thus remain useful models for the study of the effects of chemical and physical injury on the corneal surface. Although abnormalities in the basement membrane complex seem to play an important role in corneal epithelial adhesion problems, the presence of a poor substratum on which adhesion complexes must in turn rely for their stromal attachment is also an important factor.

We have investigated alterations of the metabolic state in vitamin A-deficient (A-) corneas using phosphorus-31 (31P) nuclear magnetic resonance (NMR) spectroscopy. Comparing to the control, A- corneas showed a prominent rise of phosphocreatine (PCr) as well as a total loss of glycerophosphorylcholine (GPC). Further, ATP levels were lower, and sugar phosphates (SP) and inorganic phosphate (Pi) were higher than those of the control. The accumulation of PCr and Pi, and decrease of ATP indicate that the activity of creatine kinase may be altered in vitamin A deficiency. These results suggest that vitamin A may have a role in creatine kinase activation and/or induction and that its deficiency causes a decline of energy metabolism in corneal epithelium. Moreover, disappearance of GPC implies an impaired cellular membrane metabolism. When retinyl acetate was supplied to A-rats for 5 weeks, the 31P profiles of vitamin A-repleted rat corneas recovered to normal.

Fifty-seven penetrating keratoplasties were performed using human donor corneal material stored in modified Tissue Culture Medium 199 (TC-199). Fifty-six grafts were clear on the first postoperative day and remained clear for at least three weeks. During the follow-up period (average, 3.7 months), only four additional graft failures occurred. The reduced incidence of early graft edema is attributed to prolonged viability of corneal endothelium maintained in modified TC-199 medium prior to keratoplasty.

The wearing of contact lenses has increased dramatically in the past decade; over 4 million people in the United States now use extended-wear soft contact lenses, and 9 million use daily-wear soft contact lenses. Numerous reports have caused concern that the use of soft contact lenses, especially extended-wear lenses, may result in a substantial risk of ulcerative keratitis. To examine this issue, we conducted a prospective study in five New England states to estimate the incidence of ulcerative keratitis among those who use cosmetic extended-wear and daily-wear soft contact lenses. To obtain the numerator for each estimate of incidence, we surveyed all practicing ophthalmologists in the study area to identify all new cases diagnosed over a four-month period. To provide the denominator, we conducted a survey of 4178 households to estimate the number of persons who wore each type of soft contact lens. The annualized incidence of ulcerative keratitis was estimated to be 20.9 per 10,000 persons using extended-wear soft contact lenses for cosmetic purposes and 4.1 per 10,000 persons using daily-wear soft contact lenses for cosmetic purposes (P less than 0.00001).

The terms dry eye and keratoconjunctivitis sicca (KCS) imply a condition of highly reduced or absent tear film that often is not clinically demonstrable despite the presence of other signs and symptoms. In 52 patients with KCS symptoms, either with or without tear volume reduction as measured by Schirmer's basic secretion test, we found a statistically significant increase in water evaporation rate from the tear film when compared with normal subjects. Such an increased evaporation rate might account for the tear hypertonicity known to be associated with KCS and postulated to be responsible for ocular surface damage. Thus, we propose to identify this group of paradoxically wet "dry eyes" as a "syndrome of increased tear evaporation", which better describes the pathogenesis of the ocular condition.

Bacterial viability in bacterial adherence to new soft contact lenses (SCLs) was studied by exposing polymacon and lidofilcon A lenses to Pseudomonas aeruginosa: L, live, untreated bacteria; H, bacteria heated for 1 h at 100 degrees C; and P, bacteria treated with 3% hydrogen peroxide for 1 h. Cultures of groups L, H, and P showed heavy, no, and minimal bacterial growth, respectively. Scanning electron microscopy (SEM) showed significantly less bacteria on new SCLs in groups H and P. Transmission electron microscopy (TEM) showed that bacterial shape was mostly preserved in all groups, with marked intracellular and cell membrane changes and breaks (groups H and P), margination of intracellular electron-dense material (group H), and central and peripheral vacuolation (group P). Adherence to new SCLs appears to be an active process, as killed or altered bacteria adhere less.

Electron microscopic study of an epiretinal membrane obtained from a 69-year-old black woman during pars plana vitreoretinal surgery with vitreous hemorrhage complicating a retinal vein obstruction revealed extensive proliferations of fibrous astrocytes that had secreted fibrillar and basement-membrane collagens. Hemosiderin-containing macrophages were also found. Neovascular elements were present and appeared identical to normal retinal capillaries.

Compound 48/80, a non-immunogenic mast cell degranulatory agent, is known to produce the signs and symptoms of ocular allergy. Maximal mast cell degranulation of human conjunctiva occurred within the first hour after stimulation by a single topical dose of compound 48/80 (20 microliters, 7.5 mg/ml). The average percentage of fully degranulated mast cells in treated specimens (n = 9) was 31% (range 5-60%) versus 6% (range 0-20%) in control specimens (n = 5). Exact correlates of representative granulated, partially degranulated, and fully degranulated mast cells were determined by light and transmission electron microscopy.

The water evaporation rate from the tear film of eyes with anterior surface pathology (corneal and/or conjunctival scars, meibomitis) was tested by means of the "Rolando-Refojo tear evaporimeter', which allows noninvasive and reproducible test conditions. These eyes show a statistically significant increase in tear evaporation rate compared to normal eyes. The clinical implications of this finding are discussed.

The morphologic effect of hyperosmolarity, equivalent to that seen in the tear film of patients with keratoconjunctivitis sicca (KCS), on rabbit corneal epithelium in vitro and in vivo was studied. In the in vitro studies, corneal epithelium was grown in explant cultures. Control tissue was cultured in a 307 mOsm/L medium. Epithelium cultured in the 333, 361 and 363 mOsm/L media showed decreased intercellular connections, blunting and loss of microplicae, disruptions in cell membranes and cellular swelling with decreased cytoplasmic density. In in vivo studies, corneas bathed in balanced salt solutions (BSS) concentrated to 330, 360, or 407 mOsm/L showed increased cell desquamation, and the cell changes observed at similar osmolarities in the in vitro studies. The tear film osmolarities observed in KCS are sufficient to cause the corneal epithelial changes seen in patients with this disease.

A most unusual complication of penetrating keratoplasty is the rapid thermal denaturation of a human donor cornea upon accidental exposure to temperature of 50 degrees to 60 degrees C, the result of inadequate cooling of a Teflon trephine block following autoclave sterilization.

A 21-year-old woman had typical clinical and biochemical findings of the cherry-red spot-myoclonus syndrome. She had 20/50 acuity in each eye, flutter-like ocular oscillations, rebound nystagmus, and transient vertical dissociation. Cherry-red maculas and optic atrophy were present. Although electroretinographic signals were normal, visual evoked potentials were almost absent. Levels of neuraminidase were significantly reduced in cultured ebroblasts from the patient and her parents, while lysosomal inclusions probably containing oligosaccharides were found in her conjunctival fibroblasts.

Unused soft contact lenses (SCL) containing 38.6% water (polymacon) and 70% water (lidofilcon A) were exposed to Pseudomonas aeruginosa (10(8) CFU/ml) for 60 min and washed. The contaminated lenses were used on rabbit eyes under the following conditions: for 1 h on a scratched corneal epithelium (16 eyes, four infected), for 24 h on normal cornea (eight eyes, none infected), and for 7 days on normal cornea (eight eyes, three bacterial infections and two noninfected epithelial defects). A control group of rabbits used an uncontaminated lens for 7 days (eight eyes, four noninfected epithelial defects). The control group and groups that wore contaminated lenses for 24 h and 7 days underwent tarsorrhaphy to keep the contact lens in place. In addition, three drops of the bacterial suspension were instilled in eyes with normal corneal epithelium (eight eyes, none infected) and scratched corneal epithelium (16 eyes, 13 infected). Results suggest that Pseudomonas-contaminated SCL give rise to keratitis only on an injured corneal epithelium and that a bacterial suspension is more pathogenic to the rabbit cornea than is a similar amount of bacteria on an SCL.

Monobenzone (the monobenzyl ether of hydroquinone [Benoquin]) is used topically by patients with extensive vitiligo to depigment their remaining normally pigmented skin. A patient who had been applying the drug for one year had an anterior linear deposition of pigment in both corneas. Of 15 additional patients with vitiligo, 11 of whom were using monobenzone, acquired conjunctival melanosis in two patients and pingueculae in three may have been related to monobenzone use. Light and electron microscopy of one corneal epithelial scraping and 12 conjunctival biopsy specimens revealed pleomorphic, single-membrane-limited intracytoplasmic inclusions within the corneal epithelium and within the epithelium, fibrocytes, histiocytes, and vascular endothelium of the conjunctiva. The ultrastructural aspects of these inclusions suggested that they are residual bodies containing lipid and lipofuscin.

Despite diverse and multiple clinical etiologies, the pathogenesis of noninfected corneal ulcers consistently relates to persistent or extensive epithelial defects, concomitant with stromal inflammatory cell infiltration and enzymatic degradation of collagen and ground substance. The therapeutic approaches to these disorders may be considered on three levels: (1) the determination of etiology and initiation of primary therapy; (2) promotion of epithelial healing; and (3) limitation of ulceration and support of repair, the latter aspects currently featuring pharmacologic management and limited surgical modalities, particularly the use of tissue adhesive.

Complete records from 175 patients with 176 episodes of culture-proven bacterial keratitis treated over a 4-year period at the Massachusetts Eye and Ear Infirmary in Boston were analyzed. Sixty-three percent of the infections involved gram-positive organisms, and 40% involved gram-negative organisms; 15% were polymicrobial. There was a high incidence of infection with Staphylococcus aureus (28%), coagulase-negative staphylococci (14%), diphtheroids (14%), Pseudomonas aeruginosa (14%), and Streptococcus pneumoniae (12%). Gram stain correlation was achieved in 55%. Potential predisposing factors, usually multiple, were identified in 97% of the patients. Fifty percent of the ulcers were associated with such iatrogenic factors as prior topical corticosteroid therapy, penetrating keratoplasty, and contact lens use. Trauma occurred in only 16%. Several statistically significant associations of epidemiologic factors and outcome variables were revealed. Ninety-five percent of the ulcers resolved with therapy, but only 44% of the patients had visual acuity better than the level at admission, and 13% developed major complications.

In a study of ocular tissues undergoing anaphylaxis, in uninjected rats most mast cells contained electron-dense granules with no discernible internal structure. A few cells showed varying degrees of swelling of the matrix granules. In rats injected with normal rabbit serum, more mast cells showed swelling of the granule matrix and a few showed extensive swelling of nearly all granules. Mast cells from rats undergoing anaphylaxis by either anti-IgE or antigen injection showed membrane and granule alterations: extensive dendritic processes, fusion of granule membranes, fusion between granule and plasma membranes, and disruption of plasma membranes. Communication was established between the exterior of the cell and contents of individual granules of cisternae formed by several fused granules. The matrix of nearly all granules was extensively swollen.

While the diagnostic value of vitreous culture in the management of bacterial endophthalmitis is well established, the therapeutic value of vitrectomy in this condition is debated. The present experimental study uses an aphakic model of Staphylococcus aureus endophthalmitis in the rabbit. Animals were treated with the following: (1) intravitreal antibiotics alone; (2) intravitreal antibiotics with vitrectomy; (3) vitrectomy alone; and (4) no treatment. Eyes treated with antibiotics and vitrectomy displayed significantly clearer media at 14 days after therapy compared with eyes treated with antibiotics alone. There was also a greater tendency for eyes treated with antibiotics and vitrectomy to have negative cultures at 14 days, although this difference was not statistically significant. These findings are consistent with beneficial effects of therapeutic vitrectomy as an adjunct to intravitreal antibiotic therapy in an animal model of aphakic bacterial endophthalmitis.

A highly sensitive assay for vertebrate collagenase has been developed using [14C]proline- or [3H]proline-labeled collagen as soluble substrate. The substrate was easy to prepare, gave high specific activity (1.4 X 10(6) cpm/mg collagen), and was stable at -20 degrees C for a long period. The digestion reaction for the assay was done at 21 degrees C to minimize the cleavage of collagen by proteases other than collagenase and to protect the 3/4 and 1/4 cleavage fragments of collagen from being further attacked by proteases. The cleaved products were denatured and then separated from undigested native collagen by precipitation with 1 M NaCl at pH 3.5. The conditions selected for denaturation and separation gave better discrimination between the cleaved products and uncleaved substrate than did conditions used in some other assays. The digestion products can be examined further by gel electrophoresis at the end of the assay to confirm the activity of vertebrate collagenase. This assay can also be adapted to assess telopeptidase activity independently of collagenase activity.

In previous experiments, we found that a high-water-content hydroxyethyl methacrylate (Permalens) hydrogel implant was not only well tolerated within the rabbit corneal stroma but also would successfully alter the anterior radius of curvature, and thus the refractive state, of the rabbit eye. The same lens material implanted in the cornea of a patient with aphakic bullous keratopathy was tolerated for six months and decreased epithelial edema but did not alter the refractive state. This cornea, containing the intrastromal lens, was obtained at subsequent penetrating keratoplasty and studied by light and transmission electron microscopy. Morphologically, the epithelium and anterior stroma were not edematous, whereas the stroma posterior to the lens remained edematous. Minimal fibroblastic activity was evident at the lens-stroma interface. There were no signs of inflammation, ulceration, or neovascularization.

The clinical and pathologic findings of a case of congenital bilateral, peripheral corneal leukoma associated with iris coloboma and anterior subluxation of the lens are reported. The changes in the region of keratolenticular apposition include partial absence of Bowman's membrane, stromal vascularization and thinning with large-diameter collagen fibrils, and absence of Descemet's membrane and endothelium. The authors postulate that dysembryogenesis of the tertiary vitreous, with iris coloboma, resulted in apposition of the lens to cornea during the second and third month of gestation and that this apposition resulted in the observed peripheral corneal abnormalities.

To determine the effects of thermokeratoplasty (TKP) on the basement membrane complexes of the corneal epithelium, transmission electron microscopy was performed on the corneal buttons of five patients with failed TKP and on two normal corneas and five corneas with keratoconus that were immediately treated by TKP (acute TKP). The consistent findings of thermal dissolution of basement membrane after acute TKP and persistent defects of basement membrane complexes many months after therapeutic thermokeratoplasty were significant. Given the potentially damaging effects of thermokeratoplasty on the epithelial basement membrane, faulty epithelial adhesion should be anticipated after thermokeratoplasty and should be treated aggressively, possibly with careful prophylactic use of bandage hydrophilic contact lenses.

Seven eyes and one vitrectomy specimen from seven patients with pars planitis and complications such as secondary glaucoma and phthisis bulbi were studied histopathologically. Two of the specimens were also examined by electron microscopy. All cases showed a typical intravitreal "snowbank" opacity overlying the pars plana. On light microscopy, these "snowbanks" appeared to consist of a loose fibrovascular layer containing occasional fibrocyte-like cells and scattered mononuclear inflammatory cells adjacent to the hyperplastic nonpigmented epithelium of the pars plana. Within the vitreous base, an extensive fibroglial proliferation had developed, often drawing the peripheral retina anteriorly into the "snowbank." Electron microscopy showed this fibroglial tissue to be composed of condensed vitreous collagen and probable fibrous astrocytes which had produced larger-diameter (about 24 mm) collagen fibrils. The fibroglial proliferation also appeared continuous with an ultrastructurally similar preretinal fibroglial membrane. All eyes showed prominent lymphocytic cuffing and mural infiltration of retinal veins, with sparing of the arterioles. Several cases showed cystoid macular edema. Only mild choroiditis or cyclitis could be shown in some cases. We believe that in pars planitis the fibroglial "snowbank" may reflect a common inflammatory process involving both the peripheral retina and vitreous base.

A 59-year-old woman with no evidence of glaucoma developed secondary open-angle glaucoma after an intracapsular cataract extraction complicated by vitreous and iris incarceration. Histopathologic and scanning and electron microscopic studies of the enucleated eye 22 years later revealed extensive proliferation of iris melanocytes across the trabecular meshwork and posterior surface of the cornea. Proliferation of iris stromal melanocytes over the trabecular meshwork may have caused secondary open-angle glaucoma.

The ophthalmic manifestations of a 51-year-old man with multiple myeloma included exudative retinal detachments and multiple epibulbar plasmacytomas. The retinal changes resolved with treatment for systemic effects, and the IgA-producing plasmacytomas rapidly resolved with local irradiation. The young age of onset (37 years), the prolonged course (14 years), and the IgA M protein and epibulbar involvement were, collectively, unusual findings in multiple myeloma. The presence of epibulbar, gastrointestinal tract, and prostate involvement suggested a homing mechanism of IgA-committed cells to mucosal surfaces.

Albino rabbits were treated four or six times daily with 1% prednisolone acetate, 1% medroxyprogesterone acetate, or a control vehicle, after one of three conditions. First, after 3-mm linear perforating stromal incisions; drugs were given for seven days, and wound bursting strength was determined. Prednisolone suppressed wound tensile strength by 20%; medroxyprogesterone suppressed it by 11%. Second, after trephination, drug administration for 14 days decreased collagen formation in the scar buttons by 43% in the prednisolone-treated group and 39% in the medroxy-progesterone-treated group. Third, after thermal burns; when drug application followed the burn immediately, deep ulceration or perforation developed in 85% of the controls, in none of the prednisolone-treated group, and in 17% of the medroxyprogesterone-treated group. When drug delivery was withheld until day 6, severe ulceration developed in 44% of both groups. In both experiments, stromal neovascularization was markedly suppressed by prednisolone, but only moderately decreased by medroxyprogesterone.