Benjamin Miller

Experimental Epiretinal Proliferation Induced by Intravitreal Red Blood Cells

We describe a reproducible animal model of epiretinal proliferation, based on intravitreal injection of red blood cells, that closely simulates the more benign proliferative extraretinopathies. Using light microscopy and scanning and transmission electron microscopy, we monitored the development and behavior of the experimental epiretinal membranes. We found breaks in the integrity of the retinal surface through which glial cells migrated onto the retina, proliferated into thick epiretinal tissue, and contracted to cause retinal pucker. All these steps were associated with the chronic inflammatory response to the long-lasting presence of red blood cells in the vitreous. Thus, the development of epiretinal membranes requires continuous intraocular stimulation in addition to a break in retinal integrity.

Correlation of Choroidal Subretinal Neovascularization With Fluorescein Angiography

The presence and distribution of laser-induced experimental subretinal neovascularization were studied by serial reconstruction and correlated with the amount of fluorescein leakage during angiography. All laser lesions that demonstrated leakage and pooling of fluorescein (leaky lesions) contained subretinal vessels with an overlying fluid-filled space. The subretinal vessels extended beyond the area of demonstrated leakage, while the fluid-filled space overlying the subretinal vessels correlated closely with the demonstrated area of leakage. All leaky lesions gradually stopped leaking fluorescein, that is, involuted. The disappearance of leakage was not accompanied by a reduction in the number of subretinal vessels but rather with the disappearance of the overlying fluid. Further, 80% of the lesions that never leaked fluorescein (nonleaky lesions) also contained subretinal vessels but no overlying fluid. Our findings indicate that subretinal vessels can be detected by fluorescein angiography only if they lie beneath a fluid-filled space.

Effect of timing of external dacryocystorhinostomy on surgical outcome.

Purpose: To present our experience with external dacryocystorhinostomy (DCR) outcome and to compare cases of early and late DCR. Methods: Retrospective data review of all patients who had external DCR with silicone intubation in a 7-year period. Data were collected and analyzed concerning patients’ preoperative and postoperative symptoms, and the lacrimal drainage system examination before, during, and after surgery. Results: In all, 162 patients underwent 195 DCR surgeries for nasolacrimal duct obstruction. Success was achieved in 81% of surgeries. Success rates were higher in patients who had early DCR (tearing only or early inflammatory signs of the lacrimal sac, 84% success) than in cases that had late DCR (more than 6 months after inflammation started, 77% success). These differences were statistically insignificant. Failure of DCR was much higher in posttraumatic DCR than in DCR for other etiologies. Complications (in 9% of surgeries) were generally mild and infrequent, except 1 case of meningitis. Conclusions: In experienced hands, external DCR has good postoperative success with a low complication rate. Early DCR does not have a substantial advantage over late surgery with regard to surgical outcome.

Effect of the vitreous on retinal wound-healing

The healing process of experimental retinal wounds in nonvitrectomized and vitrectomized rabbit eyes was compared. Using light, transmission and scanning electron microscopy, a significant difference was observed at the late stages of the healing process. The retinal wounds in the nonvitrectomized eyes healed properly, forming regular and smooth scars, while the scars that developed in the vitrectomized eyes were irregular and hypertrophic. Our observations suggest that the vitreous plays a role in normal healing of retinal wounds.

Orbital fractures complicated by late enophthalmos: higher prevalence in patients with multiple trauma.

Purpose: To present our experience with orbital fracture treatment outcomes in patients with multiple trauma and those suffering localized orbital trauma. Methods: Retrospective data review of all patients examined for ocular motility problems and/or enophthalmos following orbital trauma in a 4-year period. Results: Forty-three patients were included in the study: 31 (72%) had localized orbital trauma (LOT) and 12 (28%) had concomitant traumatic insults to other organs (MT). More orbital walls were affected in MT patients than in LOT patients, and the incidence of zygomatic fracture was higher in MT patients. Late enopthalmos was much more prevalent in the MT group compared with the LOT group. Differences of outcome of extra ocular motility disturbance between groups in our series did not reach statistical significance. Conclusions: The findings of more walls affected and higher incidence of zygomatic fractures in MT patients probably represent a stronger impact of the original insult, causing both more damage to other organs and more severe damage to the orbit. The increased rate of late enophthalmos in MT patients may be associated with their primary presentation to the emergency room with potentially life-threatening injuries. Under such circumstances, thorough ophthalmologic examination is nearly impossible, both because the patient cannot cooperate sufficiently and because medical priorities dictate concentration on taking care of the injuries threatening life. The lack of a thorough ophthalmic examination prevents early comprehensive treatment.

Posterior lamellar gold-weight extrusion.

We report a case of a man who had undergone gold eyelid loading for lagophthalmos 22 years earlier. During examination for a complaint of foreign body sensation in the operated eye, the gold weight was found under the palpebral conjunctiva. Although extrusion of a gold weight through the skin anteriorly is well recognized, posterior extrusion has not been previously reported. Although such an extrusion involves tarsal plate erosion, the patients complaints in this case were minor, probably due to the chronic nature of the process. This finding should serve to draw the attention of surgeons using gold eyelid loading to the possible, albeit rare, complication of posterior extrusion.

Vitreoretinal junction in infectious endophthalmitis in a primate eye.

A primate eye affected by postoperative infectious endophthalmitis was studied early in the course of the disease. Retinal perivasculitis, vitreoretinal adhesions along the inflamed vessels, and traction of the partially separated posterior vitreous on the retina at the adhesion sites were observed. It is suggested that such vitreoretinal junction pathology may be responsible for the development of retinal detachment in infectious endophthalmitis.

Ornithine decarboxylase activity during formation of experimental epiretinal membranes

This study demonstrates in a rabbit model of epiretinal membrane formation that retinal-associated ODC activity increases during this pathological process. These changes in retinal-associated ODC activity most likely occur in relationship to the proliferative lesion itself, since the retina consists primarily of nonproliferative tissues. Further knowledge of intraocular polyamine metabolism during epiretinal membrane formation which can result in retinal detachment may lead to the development of an effective pharmacological treatment.