Central corneal dermoid in a Labrador retriever puppy.

An eight-week-old, male Labrador retriever puppy was presented with an abnormal appearance of the left cornea, observed after the eyelids opened in the second week of life. Ocular examination showed a large central dermoid of the left cornea. The dermoid was excised by superficial keratectomy, and healing was uneventful. The dermoid was classified as a Mann's second type. To the authors' knowledge, a Mann's second type corneal dermoid has not previously been reported in a dog.

Lens expression of TGF alpha in transgenic mice produces two distinct eye pathologies in the absence of tumors.

Transgenic mice carrying the rat TGF alpha minigene linked to the alpha A crystallin promoter were generated to investigate the effects of expression of this growth factor in the lens of the eye. All transgenic mice exhibited eye abnormalities in the absence of overt tumors, and two distinct and heritable phenotypes were observed. Five lineages produced 'squinting' transgenic mice characterized by microphthalmic eyes with severe lens and retinal dysplasia, and four lineages produced 'bulged' transgenic mice with eyes that exhibited enlarged globes, lens epithelial hyperplasia, anterior segment dysgenesis, and in some cases retinal dysplasia. The eye perturbations of both phenotypes were evident histologically by 1 week of age, and the eyes of squinting mice were abnormal during embryonic development. The squinting phenotype was dominant over the bulged phenotype in intercrosses, suggesting that position effects from the transgene integration site resulted in differences in TGF alpha expression between the two phenotypes. In situ hybridization showed that TGF alpha transgene expression was confined to the lens or lens rudiment of all transgenic eyes despite the involvement of non-lenticular tissues in the pathology. These results show that inappropriate expression of TGF alpha in the eye can disrupt the communication required to coordinate normal eye development.

Ocular lesions in mice following intracerebral injection of herpes simplex virus type I.

A clinical isolate of type I Herpes virus was injected intracerebrally in 4-week-old Balb/C mice. Bilateral ocular disease was observed initially clinically as a leukocoria and an anterior uveitis on the 7th to 11th postinjection days. By day 21 an organized vascularized retrolental membrane had formed with resolution of active inflammation and secondary cataract formation. Light microscopy revealed the process to involve a necrotizing retinitis with associated optic nerve demyelination. Electron microscopy and tissue culture demonstrated the virus in involved tissues.

Clinical manifestations of inherited glaucoma in the beagle.

Inherited glaucoma was exhibited in 55 beagles. The glaucomatous process was divided into early (6 to 12 months of age), moderate (13 to 30 months of age), and advanced (31 months of age). In early glaucoma the tridocorneal angles, as judged by gonioscopy, were open and without anomalies, intraocular pressure was elevated, and the tonographic facility of aqueous outflow was decreased. With moderate glaucoma, the tridocorneal angles were typically open; intraocular pressure was elevated, facility of aqueous outflow was decreased; and variable optic disc cupping and focal disinsertion of the zonules from the lens were seen. Advanced glaucoma exhibited narrow to closed tridocorneal angles, decreased facility of aqueous outflow, elevated intraocular pressure, lens dislocation, optic disc atrophy, and finally phthisis bulbi. The beagle in the early and moderate stages of glaucoma, before angle closure and lens dislocation, is an animal model for studies in open-angle glaucoma.

The effect of topical pilocarpine on intraocular pressure and pupil size in the normotensive and glaucomatous beagle.

Topical 1, 2, and 4 percent pilocarpine were evaluated in the normotensive and glaucomatous beagles, comparing intraocular pressure (IOP), pupillary size, and time. In normotensive beagles pilocarpine produced maximal decreases of 25 percent (5.5 mm. Hg) at 1 percent concentration; 34 percent (7.26 mm. Hg) at 2 percent concentration; and 25 percent (6.9 mm. Hg) at 4 percent concentration. The maximum reductions in IOP after pilocarpine instillation in the glaucomatous beagle were 30 percent (9.1 mm. Hg) at 1 percent concentration; 44 percent (14.92 mm. Hg) at 2 percent concentration; and 31 percent (10.89 mm. Hg) at 4 percent concentration. The glaucomatous beagles responded with a greater reduction of IOP than did the normotensive beagles.

Evaluation of applanation tonometers for the dog eye.

The Mackay-Marg, pneumatonograph, TonAir, and EMT-20 tonometers were evaluated in the normal dog eye. Tonometric scale readings were compared to the manometric recordings from the anterior chamber. The Mackay-Marg tonometer evaluated in open and closed systems was the most reliable (goodness of fit [r2] = 0.96) with intraocular pressure up to 100 mm. Hg. The pneumatonograph also exhibited high reliability (r2 = 0.92) but tended to underestimate intraocular pressures above 40 to 50 mm. Hg. The TonAir and EMT-20 tonometers were the least satisfactory for the dog, with r2 of 0.77 and 0.66 to 0.81, respectively. The Mackay-Marg is the most satisfactory tonometer for the dog.

The organophosphate pesticide chlorpyrifos affects form deprivation myopia.

PURPOSE: The effects of the anti-cholinesterase organophosphate pesticide chlorpyrifos (CPF) on the refractive development of the eye were examined. Form deprivation was used to induce eye growth to address the previously reported relationship between organophosphate pesticide use and the incidence of myopia. METHODS: Chickens, a well-established animal model for experimental myopia and organophosphate neurotoxicity, were dosed with chlorpyrifos (3 mg/kg per day, orally, from day 2 to day 9 after hatching) or corn oil vehicle (VEH) with or without monocular form deprivation (MFD) over the same period. The set of dependent measures included the refractive state of each eye measured using retinoscopy, axial dimensions determined with A-scan ultrasound, and intraocular pressure. RESULTS: Dosing with CPF yielded an inhibition of 35% butyrylcholinesterase in plasma and 45% acetylcholinesterase in brain. MFD resulted in a significant degree of myopia in form-deprived eyes resulting from significant lengthening of the vitreal chamber of the eye. CPF significantly reduced the effect of MFD, resulting in less myopic eyes (mean refraction: VEH-MFD = -16.2 +/- 2.3 diopters; CPF-MFD = -11.1 +/- 1.8 diopters) with significantly shorter vitreal chambers. Nonoccluded eyes were, on average, slightly hyperopic. Treatment with CPF for 1 week in the absence of MFD led to no significant change in ocular dimensions or refraction relative to controls. CONCLUSIONS: The use of form deprivation as a challenge suggests that CPF treatment interferes with the visual regulation of eye growth.

Experimental intravenous digital subtraction angiography (DSA) of orbital and choroidal circulation: preliminary study.

The development of the radiologic technique, digital subtraction angiography (DSA), has substantial importance in studying the uveal vasculature and its orbital blood supply. After rapid intravenous injection of commercially available contrast material, images of the orbital and uveal vessels of rabbits, cats, and the nonhuman primate can be observed. Advantages and limitations of this new technique for visualization of uveal and orbital vasculature were evaluated in serial experimental animal studies. Future potential clinical applications are discussed.

Vascular casting and scanning electron microscopy of human ocular vascular abnormalities.

Plastic casts of ocular vessels were made from postmortem specimens obtained from patients who had had hypertension and arteriosclerosis, diabetes mellitus, and retinopathy of childhood. In conjunction with scanning electron microscopy, the casts serve as models of pathologic vascular changes, including arteriovenous crossing defects, microaneurysm, localized capillary nonperfusion, and rapidly growing peripheral choroidal vessels. These preliminary findings should serve to encourage further study of ocular vascular abnormalities with the use of plastic casting techniques.

Sarcoidosis and ocular disease in a young child. A case report and review of the literature.

Uveitis in the very young child may be a manifestation of sarcoidosis. A case of sarcoidosis with intraocular inflammation that occurred in a child 2 years 7 months old is reported. The diagnosis was supported by biopsy of uncommon bulbar conjunctival nodules. Knowledge by the ophthalmologists that this disease can occur in children younger than 5 years of age may be crucial to the establishment of proper diagnosis.

Scanning electron microscopy of the ocular vasculature in retinopathy of prematurity.

Clinicoanatomopathologic correlations in a case of the retinopathy of prematurity are reported. A premature infant delivered at 28 weeks of gestation (weight, 900 g) was hospitalized for a number of health problems, including bronchopulmonary dysplasia and respiratory distress syndrome. Ophthalmic examination, at the age of 5 months, disclosed stage 1B retinopathy of prematurity. The patient died at the age of 161 days; both eyes were taken for scanning electron microscopy and histopathologic studies. Scanning electron microscopy findings included absence of retinal capillaries, anterior uveal neovascularization originating from the venous side, and a coincidental typical coloboma of the optic nerve and choriocapillaris. Histopathologic findings confirmed iris stromal neovascularization, showed retinal neovascularization with proliferation into the vitreous and avascular areas between the midperiphery and ora serrata.

Episcleral and orbital pseudorheumatoid nodules.

Pseudorheumatoid nodules are subcutaneous necrobiotic granulomas that are histopathologically similar or identical to those seen with rheumatoid arthritis, granuloma annulare, necrobiosis lipoidica diabeticorum, and systemic lupus erythematosus. Although these nodules are most common in children, they are also seen in adults and are usually located on the extremities and scalp. Eyelid and eyebrow involvement is seen infrequently. We histopathologically verified episcleral and orbital pseudorheumatoid nodules in an adult with eyelid and eyebrow nodules. Pseudorheumatoid nodules must be included in the differential diagnosis of subconjunctival mass lesions that may concomitantly involve the orbit, episclera, and periocular region.

Protective effects of viscous solutions in phacoemulsification and traumatic lens implantation.

We compared the endothelial protection offered by 1% hyaluronate sodium (Healon), 3% hyaluronate sodium and 4% chondroitin sulfate (Viscoat), and a nonviscous irrigating solution (BSS Plus) during phacoemulsification with and without traumatic intraocular lens implantation. Vital-dye staining and scanning electron microscopy were used to determine acute damage to rabbit corneal endothelium. Cell damage during phacoemulsification alone was not significantly different from that in unoperated controls (12.5%). Cell damage after traumatic lens insertion was significantly greater in the groups treated with BSS Plus (76.2%) and Healon (41.4%) than in either paired Viscoat-treated group (21.1% and 17.4%, respectively). Viscoat (but not Healon) was noted to be adherent to the cornea at the end of the procedure in one third of the cases, indicating that Viscoat remains in the anterior chamber during surgery. We attribute this to chondroitin sulfate's newtonian characteristics, allowing it to maintain viscosity in the face of high flow rates.

Inhibition by MIF-I of alpha-MSH induced increase of intraocular pressure and miosis in rabbits.

The effects of intracameral (i.c.) administration of MIF-I on the ocular response to alpha-MSH were tested in rabbits. In confirmation of previous studies, i.c. alpha-MSH significantly increased intraocular pressure (IOP) and reduced pupillary diameter (PD). Concomitant administration of alpha-MSH and MIF-I antagonized both the IOP increase and miosis induced by alpha-MSH. Aqueous humor (AH) dynamics studies revealed that alpha-MSH increases IOP, possibly, by decreasing AH outflow. The decreased AH outflow induced by alpha-MSH was antagonized by concurrent administration of MIF-I and alpha-MSH. MIF-I did not affect IOP or PD when administered alone. These results add more support for a role of alpha-MSH in ocular function, and suggest that the ocular response to alpha-MSH may be subject to inhibitory control by MIF-I.

Intracameral administration of alpha-MSH increases intraocular pressure in rabbits.

A growing body of evidence suggests that neural peptides may induce important modulations on vegative and motor functions of the eye. The present study was designed to evaluate the effect of intracameral (I.C.) administration of alpha-melanocyte-stimulating hormone (alpha-MSH) and several other ocular peptides on intraocular pressure (IOP) in rabbits. alpha-MSH (5 micrograms) produced a significant and prolonged unilateral increase of IOP. This effect of I.C. alpha-MSH was dose-dependent (ED50 = 2.5 micrograms). Structure-activity studies revealed that equimolar doses of beta-MSH and gamma-MSH, unlike alpha-MSH, were totally ineffective. In addition, the structurally unrelated peptides beta-endorphin, thyrotropin-releasing hormone (TRH) and gonadotropin-releasing hormone (Gn-RH) did not affect IOP, when tested in a dose equimolar to 5 micrograms of alpha-MSH. These results confirm and extend previous observations, suggesting that alpha-MSH may be an important factor involved in regulation of IOP.

Intracameral administration of neurotensin induces miosis in the rabbit.

The present investigation was designed to evaluate the effect of selected peptides on pupillary diameter and intraocular pressure (IOP) in rabbits. Intracameral (IC) administration of neurotensin (NT) in doses of 5-100 micrograms produced a significant, long lasting and dose-dependent decrease in pupillary diameter without affecting IOP. NT-induced miosis appears to be relatively specific because a variety of peptides including Gn-RH, somatostatin, met-enkephalin, bombesin, leu-enkephalin or NT1-6, (a biologically inactive N-terminal fragment of NT), produced no effect on pupillary diameter; only substance P produced miosis similar to NT when tested in a dose equimolar to 30 micrograms of NT. In addition, peripheral (intravenous) administration of NT (100 micrograms/kg) was equally ineffective. Inhibition of prostaglandin synthesis with indomethacin, did not prevent subsequent NT-induced miosis. Finally, IC administration of an effective dose of NT (30 micrograms) did not alter the protein concentration in the aqueous humor. These results indicate that NT-induced miosis is not mediated by endogenous prostaglandins and that this effect of NT does not appear to involve disruption of the blood-aqueous barrier, suggesting that NT may play a role in regulation of pupillary diameter.

Mucinous sweat gland adenocarcinoma of the eyelid.

A 62-year-old woman developed a recurrent mucinous sweat gland adenocarcinoma of the eyelid. The clinical characteristics of this rare, primary adnexal neoplasm of skin in our patient were, to our knowledge, unique. The tumor mimicked a lacrimal sac tumor and had orbital extension demonstrated preoperatively by computed axial tomography. Orbital extension of the tumor mass was confirmed during a wide, en bloc, excisional biopsy.

Chorioretinal foreign body simulating malignant melanoma.

A 37-year-old man underwent an enucleation of his left eye because of a lesion that demonstrated the clinical and fluorescein angiographic characteristics of a malignant melanoma. Histologic examination of the eye disclosed a chorioretinal inflammatory mass caused by refractile crystalline material.

Choroidal malignant melanoma in siblings.

Choroidal malignant melanoma was diagnosed on pathologic examination of enucleated globes from a 54-year-old man and his 58-year-old sister. The brother had been monitored at four-month intervals for four years because of a choroidal lesion, which abruptly increased in size, in his left eye. Three years after an examination with normal findings, the sister developed a retinal detachment with a pigmented dome in her right eye. Both patients are doing well five years (Patient 1) and two years (Patient 2) after enucleation. Screening examinations detected two cases of benign melanoma (nevi) in 18 close relatives but this incidence did not exceed chance.

Comparison of the effect of polymethylmethacrylate and silicone intraocular lenses on rabbit corneal endothelium in vitro.

An in vitro comparison of corneal endothelial damage caused by polymethylmethacrylate and by silicone intraocular lenses was made. Endothelial damage was assessed by vital staining of corneal endothelium immediately following direct contact with an intraocular lens. Silicone lenses produced less damage than polymethylmethacrylate lenses. The difference could be attributed to a specific type of damage-membrane stripping-seen only after contact with polymethylmethacrylate lenses.