Efficacy of transpupillary thermotherapy (TTT) in the treatment of occult subfoveal choroidal neovascularization in age-related macular degeneration.

PURPOSE: To determine the efficacy of transpupillary thermotherapy (TTT) in the treatment of occult subfoveal choroidal neovascularization in patients with age-related macular degeneration (ARMD). METHODS: We conducted a retrospective review of patients with ARMD treated with TTT from June, 1999 through July, 2000 at a retina referral practice. TTT was delivered through a slit-lamp using a modified diode laser at 810 nm wavelength and a spot size of 3 mm delivered at one location for a minimum of 60 seconds duration. Re-treatment was performed at 2-month intervals if indicated. RESULTS: 81 eyes of 77 patients were included in the study. Vision improved greater than one line Snellen in 18 eyes (22%), vision was stable within one line Snellen in 38 (47%), and worsened greater than one line Snellen in 25 (31%). Patients had a mean follow-up of 9 months. The average number of treatments was 1.37 (range 1 to 4). Pretreatment vision was less than or equal to 20/200 in 54% of eyes. CONCLUSIONS: Transpupillary thermotherapy may stabilize visual acuity in a majority of patients with occult subfoveal choroidal neovascularization secondary to ARMD. Proof of therapeutic benefit is best determined by a randomized clinical trial that is currently underway (TTT4CNV).

Macular translocation with radial scleral ouffolding: experimental studies and initial human results.

PURPOSE: Different techniques have been proposed for translocating the macula in patients with subfoveal neovascularization secondary to age-related macular degeneration. A new approach utilizing radial outfolding of the sclera was investigated. MATERIALS AND METHODS: Surgical techniques and retinal displacement were evaluated in animal trials using metal scleral clips. Successful translocation and reattachment of the retina was achieved in eight rabbits (eight eyes). We conducted a retrospective review of macular translocation surgery, performed with radial scleral outfolding, in a series of five consecutive human patients (five eyes) using full-thickness transscleral mattress sutures. RESULTS: After surgery, vision improved in two of five patients, with one patient achieving a visual acuity of 20/50. The mean angle of rotation was 11.5 deg (range 8.6 -15.1). The mean amount of foveal displacement was 1,276 pm (range 852-1,620). Complications included one case of retinal detachment, one of diplopia, and one of subretinal hemorrhage. CONCLUSIONS: Limited macular translocation by radial scleral outfolding can improve vision in selected patients. Radial evagination appears to be as effective as circumferential infolding.

Transcorneal oxygen therapy for glaucoma associated with sickle cell hyphema.

PURPOSE: To study three patients with glaucoma caused by sickle cell hyphema who were successfully treated with transcorneal oxygen therapy. METHODS: Case reports. Three patients with increased intraocular pressure caused by sickle cell hyphema were administered transcorneal oxygen therapy using humidified oxygen at a flow rate that ranged from 1 to 3 l/minute. RESULTS: All three patients had a dramatic reduction in their intraocular pressure within hours of receiving oxygen therapy. No complications were associated with the oxygen therapy. CONCLUSION: Transcorneal oxygen therapy can reduce intraocular pressure in patients with glaucoma from sickle cell hyphema. Further study is warranted to evaluate this new therapy.

The effect of silicone ocular surgical devices on serum IgG binding to silicones.

PURPOSE: To determine whether silicone materials used in retinal detachment repair and cataract surgery increase serum IgG binding to silicone and identify correlations with complications of ocular surgery. METHODS: Serum from 49 patients who had ocular surgery using silicone materials was examined. Patient groups included scleral buckling (n = 25), silicone oil tamponade (n = 3), scleral buckling and silicone oil tamponade (n = 9), and silicone lens implants after cataract extraction (n = 12). Convalescent samples for all patients and preoperative samples from 19 patients (18 scleral buckling and one silicone oil tamponade) were examined. Postoperative complications were monitored for up to 108 months (mean, 10.7 months; mode, 1.5 months; range, 1 to 108 months). Samples were evaluated for the extent of IgG binding to silicones using a micromodification of a previously described enzyme-linked immunosorbent assay method. RESULTS: In 19 patients, IgG binding levels in preoperative samples were 21 arbitrary units (AU) or less. Of the 25 buckling patients, one developed complications; however, in all patients the postoperative levels of IgG binding to silicone were low (2.2 to 20.0 AU). Although four silicone lens patients developed mild complications, none displayed postoperative IgG binding levels of greater than 20 AU. Three patients who underwent both scleral buckling and silicone oil tamponade developed complications; one of these patients, who was also noted to have systemic connective tissue disease, had a significant elevation in postoperative serum IgG binding to silicone. CONCLUSIONS: Statistically significant elevations of serum IgG binding to silicone were noted postoperatively in only one patient who had a systemic connective tissue disease. The complication rate and frequency of enhanced serum IgG binding to silicone was low, making correlations to surgical complications difficult. Examination of matched samples suggested that if ocular exposure to silicone implants enhances the level of serum IgG binding to silicones, it must be a rare event that should not alter the clinical use of these important devices.

Subretinal hemorrhages in proliferative diabetic retinopathy.

PURPOSE: To describe the clinical features of patients with advanced proliferative diabetic retinopathy who underwent vitrectomy and were found to have subretinal hemorrhages. METHODS: The authors conducted a retrospective study of 49 patients with complications of proliferative diabetic retinopathy requiring pars plana vitrectomy and demonstrating the presence of subretinal hemorrhage. Preoperative, intraoperative, and postoperative clinical characteristics were evaluated. Patients were observed for a minimum of 6 months. RESULTS: The location, size, and clearance of subretinal hemorrhages revealed wide variation. Forty-two patients had focal subretinal hemorrhages, and 14 patients within this group had submacular hemorrhages. A retinal break was observed in 15 patients (31%). Only one patient required drainage of the subretinal hemorrhage to achieve retinal reattachment. Vitreous surgery resulted in 59% of patients achieving a visual acuity > or = 5/200. Seventy-nine percent had stable or improved vision, whereas 20% had worse vision after surgery. CONCLUSION: Subretinal hemorrhages appear to be an uncommon feature associated with long-term, advanced proliferative diabetic retinopathy and portend a guarded visual prognosis. These hemorrhages may occur spontaneously in previously untreated eyes and are often unsuspected until observed at the time of vitreous surgery. In general, removal of subretinal hemorrhages was not necessary to achieve macular anatomic attachment, and most patients experienced improved visual function after surgery. Diabetic subretinal hemorrhages may indicate a retinal break, and, therefore, careful ophthalmic inspection should be performed in these patients.

An infusion temporary keratoprosthesis for pars plana vitrectomy.

PURPOSE: To develop a temporary keratoprosthesis with integrated infusion cannula to minimize retinal complications during pars plana vitrectomy in eyes with an opaque cornea. METHODS: The wide-field temporary keratoprosthesis has been modified to include an integrated infusion cannula. The 20-gauge cannula runs from the periphery of the corneal flange, bends 90 degrees, and enters the eye after passing through the periphery of the corneal cylinder. RESULTS: The infusion wide-field temporary keratoprosthesis has been used successfully in three cases without the need to place a separate infusion, which risks iatrogenic retinal breaks or retinal dialyses. Droplet condensation on the posterior surface of the infusion temporary keratoprosthesis was reduced compared with the standard temporary keratoprosthesis. CONCLUSION: We have developed a wide-field temporary keratoprosthesis with an integrated infusion cannula for use during pars plana vitrectomy in eyes with severe corneal opacity. This device eliminates the risk of complications related to the pars plana infusion cannula.

Fibrinolysis of experimental subretinal haemorrhage without removal using tissue plasminogen activator.

AIMS/BACKGROUND: Human recombinant tissue plasminogen activator (rt-PA) fibrinolysis of subretinal haemorrhage with concomitant removal has been shown to reverse the natural history of photoreceptor degeneration in experimental subretinal haemorrhages if evacuated within 7 days. The aim of the study was to determine whether fibrinolysis of subretinal haemorrhage without concomitant removal would offer a simpler approach with similar photoreceptor sparing. METHODS: A neodymium YAG laser was used to create experimental subretinal haemorrhages beneath the holangiotic retina of the cat. Tissue plasminogen activator (10 micrograms/ml) was injected into 4 day old subretinal haemorrhages to evaluate its effect on altering the natural history of retinal degeneration. Light and electron microscopy were used to study the histopathological effect. RESULTS: The injection of rt-PA into large 4 day old subretinal haemorrhages without concomitant removal did not alter the natural history of retinal degeneration. In fact, a second focus of retinal degeneration occurred at a gravity dependent inferior site where the subretinal haemorrhages had migrated. CONCLUSIONS: There was no therapeutic benefit from the injection of rt-PA into subretinal haemorrhages without con-comitant removal in this cat model.

Comparison of techniques for transscleral diode photocoagulation in the rabbit.

PURPOSE: To assess the optimum probe design and treatment parameters for transscleral diode laser retinopexy. METHODS: Transscleral diode photocoagulation was performed on the eyes of Dutch-belted rabbits using three different transscleral probes: a straight, 400-microns diameter probe; a prism-tipped 400-microns diameter probe; and a prism-tipped 900-microns diameter probe. RESULTS: Transscleral diode photocoagulation with all three probe types was an effective method of ablating the retina and creating chorioretinal adhesions. Both the burn diameter and the mean radiant output energy requirement increased as the burn duration and probe aperture diameter was increased. Explosive retinal holes were encountered in 12% of the burns created with the straight probe. The use of the prism-tipped probes significantly reduced the incidence of retinal holes to < 4% (P < 0.005). Histopathologically, all burns were grade III in intensity with severe choroidal injury. In many of the burns, there was histopathologic evidence of thermal injury to the inner sclera. The frequency of these inner scleral changes was reduced with a long burn duration (5 seconds). CONCLUSION: This study confirms that diode transscleral photocoagulation is a feasible method of thermal retinopexy. The use of the prism-tipped probes and long duration burns resulted in the fewest adverse reactions.

Transcorneal oxygenation of the preretinal vitreous.

OBJECTIVE: Transcorneal oxygenation is a promising approach to the treatment of various anterior ocular diseases, but its effect on the vitreous and retina is uncertain. The purpose of this study was to evaluate the ocular conditions necessary to permit transcorneal oxygenation of the preretinal vitreous in the rabbit eye. METHODS: Oxygen at atmospheric pressure was supplied via a goggle to the eye while preretinal oxygen tensions were measured with a minimally invasive technique: fluorine-19 (19F) nuclear magnetic resonance spectroscopy of a small preretinal droplet of perfluorotributylamine. Experiments were performed on lensectomized eyes with intact posterior lens capsules (group 1) or in eyes that had also undergone posterior capsular discission (group 2) and mechanical vitrectomy (group 3). To better understand the results of the oxygenation studies, a water-soluble, freely diffusible contrast agent was applied topically to the cornea, and its penetration into the aqueous and vitreous was studied using T1-weighted magnetic resonance imaging. RESULTS: Preretinal PO2 was significantly increased after 30 minutes of transcorneal oxygenation in group 3 eyes (P = .002). In contrast, no change was observed in the other groups despite 30 minutes (group 1) or 3 hours (group 2) of oxygen exposure. The imaging studies demonstrated that contrast penetration of the vitreous was uniform and rapid in eyes in group 3, consistent with a fluid flow-dominated process. A much slower process of anterior and midvitreous enhancement was observed in groups 1 and 2 that was consistent with contrast diffusion. CONCLUSIONS: Because of bulk fluid movement, transcorneal oxygenation of the retina is feasible in single-compartment (vitrectomized, lensectomized) eyes within a reasonable period (30 minutes). This finding could prove useful in the treatment of retinal diseases in which hypoxia may play a role.

Fibrinolytic-assisted removal of experimental subretinal hemorrhage within seven days reduces outer retinal degeneration.

PURPOSE: To better determine the surgical window for removing experimental subretinal hemorrhages in the cat model and to compare the histopathologic effect of such removal with the natural history of untreated subretinal hemorrhages. METHODS: Twenty-three large experimental subretinal hemorrhages were created with a neodymium:YAG laser focused through a performed retinal bleb in a cohort of cats. Fourteen subretinal hemorrhages were observed without treatment, six were removed at 7 days through a micropipette after injecting 10 micrograms/ml of human recombinant tissue plasminogen activator (rt-PA) into the subretinal space, and three were removed through an access retinotomy without the use of rt-PA. The tissues from these eyes were examined with light and electron microscopy 14 to 28 days after creation of the subretinal hemorrhages. RESULTS: Severe outer retinal degeneration was evident by day 14 in all of the untreated subretinal hemorrhages 3 disc diameters or greater in size. In contrast, the outer retinal architecture was better preserved in the eyes that underwent rt-PA-assisted removal of their subretinal hemorrhage that was 3 disc diameters or greater on day 7. In these eyes, mild abnormalities such as abnormally short and misaligned photoreceptor outer segments with vacuolization were present within the retina that was formerly located over the hemorrhage center. The eyes that underwent subretinal hemorrhage removal through an access retinotomy without rt-PA on day 7 had a low-lying retinal detachment and outer retinal degeneration. CONCLUSION: Removing experimental subretinal hemorrhages within 7 days of their occurrence with the assistance of rt-PA and an ultramicrosurgical approach may reduce outer retinal degeneration in the cat model.

[A report of 412 consecutive posterior chamber intraocular lens implantations].

The series of 412 consecutive PC IOL implantations comprised 337 eyes of senile cataract, 16 eyes of membranous cataract, 25 eyes of traumatic cataract, 13 eyes of congenital cataract, 10 eyes of complicated cataract and 11 eyes of aphakia. 362 eyes were postoperatively followed up from 4 weeks to 1 1/2 years with the results that 251 (69.3%) eyes obtained visual acuities of 0.8 or over, and 328 (90.6%) eyes 0.5 or over. The authors discussed the technical improvement in anterior capsulotomy and the implantation procedures in cases of posterior capsule rupture. The importance of postoperative control and management of astigmatism, in the recovery of visual acuity was pointed out.

A comparison of argon and diode photocoagulation combined with supplemental oxygen for the treatment of retinopathy of prematurity.

The efficacy of argon and diode laser photocoagulation of the avascular peripheral retina for threshold retinopathy of prematurity (ROP) was compared in a prospective trial. The study group included 9 premature infants (17 eyes). In each infant, one eye was treated with the diode laser indirect ophthalmoscope (LIO), and the fellow eye was treated with the argon LIO. Supplemental oxygen therapy was administered after laser treatment to all nine infants. The mean duration of the follow-up period was 9.7 +/- 2.6 months. All 17 eyes (100%) had complete regression of ROP and favorable outcomes. The diode and argon LIO appear to be equally effective in treating threshold ROP. Two patients sustained burns of the tunica vasculosa lentis and anterior lens capsule in the argon laser treated eye but not in the fellow diode treated eye. Photocoagulation with either the diode or argon LIO, combined with supplemental oxygen treatment, appears to be a promising treatment for retinopathy of prematurity.

Intraocular fluid cultures after primary pars plana vitrectomy.

To determine what organisms enter the eye and remain in the eye after pars plana vitrectomy, vitreous cavity aspirates were cultured postoperatively. Two of 33 (6%) consecutive eyes undergoing primary pars plana vitrectomy had positive cultures. One sample grew a single colony of Staphylococcus epidermidis, the second grew two colonies of Acinetobacter lwoffi. Neither of these eyes developed endophthalmitis. This study demonstrates that bacteria enter the eye at a low rate during pars plana vitrectomy and that the eye on which a vitrectomy has been performed is capable of clearing a low inoculum of bacteria.

Comparison of photocoagulation with the argon, krypton, and diode laser indirect ophthalmoscopes in rabbit eyes.

PURPOSE: The purpose of this study is to compare photocoagulation with the argon green, krypton red, and diode infrared laser indirect ophthalmoscopes in an experimental setting. METHODS: Photocoagulation was performed with each of the laser indirect ophthalmoscopes in a grid pattern within one sector of the same eye of 14 Dutch-belted rabbits. Treatment was performed either with or without scleral depression. Measurements of the retinal burn diameters were performed after hemisecting the globes, and the burns were examined with light microscopy. RESULTS: Variation in burn intensity and diameter (10% to 28%) was common with all 3 laser indirect ophthalmoscopes. Five times more output energy was required to make equivalent burns with the diode laser indirect ophthalmoscope than with the argon or krypton laser indirect ophthalmoscopes. Choriovitreal hemorrhages only occurred during scleral depression. Histopathologically, the argon green laser indirect ophthalmoscope burns spared the choroid and inner sclera, while the intense krypton and diode burns had full-thickness choroidal involvement and even thermal injury to the inner sclera. Scleral depression reduced the mean energy required to create equivalent burns with all three laser indirect ophthalmoscopes. There was a 10% to 40% reduction in the mean retinal burn diameter with scleral depression (argon green, P < 0.0005; krypton red, P < 0.0005; and diode, P < 0.025). CONCLUSION: Photocoagulation with the argon green, krypton red, or diode infrared laser indirect ophthalmoscopes is a safe and effective method of retinal ablation. Decreasing the posterior nodal distance of the eye with scleral depression will produce a smaller spot on the retina with the laser indirect ophthalmoscope.

Ultramicrosurgical removal of subretinal hemorrhage in cats.

Subretinal hemorrhages are associated with progressive degeneration of the outer retina and a corresponding poor visual prognosis. Mixed results have been reported in previous attempts to remove such subretinal hemorrhages. We developed an ultramicrosurgical system that used the control of a stereotactic micromanipulator to direct a micropipette tip through a small retinotomy into the subretinal space in three cat eyes. Low-dose recombinant tissue plasminogen activator was then introduced into the subretinal space around the subretinal hemorrhage via a controlled microinfusion system. The recombinant tissue plasminogen activator solution facilitated clot lysis and subsequent removal through the micropipette. Light- and electron-microscopic analysis of histopathologic specimens disclosed good preservation of retinal architecture in the three cat eyes in which experimental subretinal hemorrhages were removed. This was in contrast to the retinal degeneration observed in similar but untreated experimental subretinal hemorrhages.