Retinal Toxicity Following the Injection Ganciclovir into Silicone Oil-filled Eye to Treat Acute Retinal Necrosis

PURPOSE: To report a case of retinal toxicity after an intravitreal ganciclovir injection to treat acute retinal necrosis in an eye filled with silicone oil.CASE SUMMARY: A 56-year-old male presented with ocular pain and visual loss in his right eye. His best-corrected visual acuity was 20/25, inflammatory cells in the anterior chamber, multiple retinitis lesions and retinal vessel occlusions in the peripheral retina and vitreous opacity were showed. Acute retinal necrosis was suspected, anterior chamber polymerase chain reaction (PCR) test was done. Aciclovir 2,400 mg/day intravenously and ganciclovir 2.0 mg were administered by intravitreal injection. After 4 days, retinitis was worsened and PCR test was positive for varicella zoster virus. Ganciclovir intravitreal injections were increased twice a week. After 16 days, retinal detachment occurred, so scleral encircling, vitrectomy, laser photocoagulation, and silicone oil tamponade were conducted. Ganciclovir 1.0 mg was injected at the end of surgery. The patient's visual acuity decreased to hand motion, and multiple crystal deposits with multiple retinal hemorrhages were observed in the right eye the next day. Visual acuity did not recover and optical coherent tomography showed that the macula was thinned.CONCLUSIONS: Visual loss seemed to be related with the retinal toxicity of ganciclovir. The increased local concentration due to the silicone oil tamponade is thought to have caused the toxicity.

Caution of retinal toxicity using chloroquine and hydroxychloroquine in the treatment of COVID-19 / 国际眼科杂志(Guoji Yanke Zazhi)

@#“Chloroquine phosphate” was listed as a trial drug in diagnosis and treatment program of COVID-19(trial sixth edition), and the application of chloroquine and hydroxychloroquine treatment for COVID-19 in medical institutions also increased. Chloroquine and hydroxychloroquine have certain retinal toxicity, its mechanism is still unclear, due to different drug tolerance, the risk degree of retinal toxicity in COVID-19 treatment is unclear. Therefore, when using chloroquine and hydroxychloroquine in the treatment of COVID-19, it is recommended to choose the appropriate dosage according to patients' situation, and adopt necessary ophthalmic screening for patients with high risk to prevent the occurrence of retinopathy. In this paper, we described the risk factors, clinical manifestations and screening methods of retinal toxicity caused by chloroquine and hydroxychloroquine, in order to provide references for the safer use of chloroquine and hydroxychloroquine in the treatment of COVID-19.

Multimodal imaging characteristics of hydroxychloroquine retinopathy

Hydroxychloroquine (HCQ) is known to cause retinal toxicity. Early detection of the toxicity is necessary to stop the drug in time. Multicolor imaging (MC) is a new noninvasive retinal imaging modality that simultaneously acquires three reflectance images of the retina using three individual lasers producing a composite image, thereby allowing analysis of changes at various levels within the retina. It is a new and promising addition to the retinal imaging armory. MC characteristics of HCQ toxicity are hitherto unreported. A 61-year-old female presented with history of HCQ intake (400 mg/day) for the last 6 years. She had retinopathy in both eyes. Multicolor composite image showed circumscribed perifoveal arcuate area of darkening, and infrared reflectance showed speckled hyperreflecetance in both eyes. MC imaging shows definite changes in HCQ toxicity, and it might emerge as a possible screening tool in future.

Hidroxicloroquina y retinopatía en pacientes reumatológicos / Hydroxychloroquine use and retinopathy in rheumatologic patients

: relacionar el uso de hidroxicloroquina con la presencia de retinopatía en pacientes reumatológicos. Métodos: se realizó un estudio retrospectivo y descriptivo, de revisión de historias clínicas de pacientes reumatológicos en tratamiento con hidroxicloroquina. Se seleccionaron aquellos con evaluación oftalmológica previa al inicio del tratamiento y estudios como la OCT-SD. Se recolectaron variables clínico epidemiológicas, cálculo de dosis diaria y acumulada del fármaco, y duración del tratamiento. Resultados: se revisaron 150 historias, de las cuales 47 cumplieron con los criterios de inclusión; 44 (93,6%) eran del género femenino y 3 (6,4%) del género masculino. La edad promedio fue de 47 ± 14 años. La hipertensión arterial fue la comorbilidad más frecuente. La patología reumatológica más frecuente fue el Lupus (53,2%). La dosis diaria de hidroxicloroquina fue ≤ 6,5 mg/kg/día en los 47 pacientes; el tiempo promedio de consumo fue de 5 años; y la dosis acumulada promedio fue de 498,5 ± 503,68 gramos. Se detectó toxicidad retiniana en 18 pacientes (38,3%), de los cuales: 17(36,2%) tuvo daño precoz y 1 (2,1%) daño moderado. Se observó relación estadística significativa entre toxicidad retiniana y dosis acumulada menores a 1.000 gramos (p= 0,032) y un tiempo de consumo mayor o igual a 5 años (p = 0,045) Conclusiones: las alteraciones iniciales en las capas externas de la retina ayudan a la detección precoz de toxicidad retiniana por hidroxicloroquina, siendo la OCT-SD un método sensible y fácil de realizar en la práctica clínica(AU)

To establish the relationship between the use of hydroxychloroquine and retinopathies in rheumatologic patients. Methods: This is a retrospective, descriptive study of the medical charts of rheumatologic patients' who were receiving hydroxychloroquine. We selected patients previously seen in ophthalmologic services, and ophthalmologic coherence tomography (SD OCT) had been realized. We collected clinical and epidemiologic variables such as daily doses, accumulated doses and prescription duration. Results: we selected 47 medical charts; the female gender is 44 and three gender male. Mean age was 47 +14 years.Hypertension was the most frequent comorbidity.Lupus was the most frequent rheumatologic illness.Hydroxychloroquine daily dose was < 6.5 mg/Kg/day and treatment`s mean duration was 5 years; average accumulated dosage was 498.5 + 503.68 grs. We established retinal toxicity in 18 patients (38.3%), in which 17 (36.2%) had early damage, and 1(2.1%) had moderated damage. There was a statistical correlation between retinal toxicity and accumulated doses of less than 1.000 grs. (p: 0.032) as well as with time of use > 5 years (p:0.045) Conclusions: Early alterations of retinal superficial layers help in the detection of early retinal toxicity due to hydroxychloroquine use. OCTSD is a feasible and sensible study in daily medical practice(AU)

Gentamicin-Induced Macular Toxicity after Transconjunctival Sutureless 23-Gauge Vitrectomy with Prophylactic Subconjunctival Gentamicin Injection

PURPOSE: To report a case of macular toxicity due to gentamicin after transconjunctival 23-gauge sutureless vitrectomy with prophylactic subconjunctival gentamicin injection. CASE SUMMARY: A 60-year-old female presented to our department with decreased vision in her left eye that had persisted for several months. Best corrected visual acuity (BCVA) was 0.5 in the left eye and she was diagnosed with epiretinal membrane and lamellar macular hole. The patient underwent transconjunctival 23-gauge sutureless vitrectomy with epiretinal membrane removal and intravitreal gas injection. Prophylactic subconjunctival gentamicin injection was given at the end of surgery. After 1 week, fundus examination of the left eye showed multiple retinal hemorrhages around inferior temporal vascular arcade. After six weeks, the patient underwent extracapsular cataract extraction with posterior chamber intraocular lens implantation in the left eye. After cataract surgery, BCVA of the left eye was 0.16 and atrophic change with retinal hemorrhage of the macula was observed on fundus examination of the left eye. Fluorescein angiography revealed multiple occlusion of temporal retinal arteries and capillaries of the macula. CONCLUSIONS: When a prophylactic subconjunctival drug is injected at the end of transconjunctival sutureless vitrectomy, the drug can inflow into the intraocular space through sutureless sclerotomy sites and induce retinal toxicity.

Spectral domain optical coherence tomography for early detection of retinal alterations in patients using hydroxychloroquine.

Objective: To determine whether early toxic effects from hydroxychloroquine (HCQ) could be detected by spectral-domain optical coherence tomography (SD-OCT) before symtomatic visual loss occured. Materials and Methods: Fifteen subjects with a history of the chronic use of hydroxychloroquine monotherapy for less than five years without fundus changes (group 1) and 15 visually normal healthy subjects (group 2) were enrolled in this study. All participants underwent systemic and ocular examination, visual field testing, and macular scan imaging using SD-OCT. Results: There were no significant differences in sex and ages between the groups (P > 0.05). Mean duration of HCQ usage in group 1 was 2.5 ± 1.34 (range:1-5) years. Visual field testing with central 10-2 threshold program was normal in all subjects. Inner retinal thickness in parafoveal and perifoveal area were found to be significantly lower in group 1 compared to group 2 (P < 0.01 for perifoveal, P < 0.05 for parafoveal retinal measurements). However, significant thinning was demonstrated only in full retinal thickness of perifoveal area in group 1 compared to group 2 (P: 0.013). Parafoveal and perifoveal inner retinal thickness measurements of inferior quadrants were significantly reduced in group 1 compared to group 2 (P < 0.01). Conclusion: Significant thinning of inner retinal layer especially in parafoveal and perifoveal areas in the absence of clinical fundus changes was observed in our study. We consider that SD-OCT may determine when inner retinal thinning starts in these patients and may contribute a quantitative approach to the early diagnosis and progression of retinal changes.

Hip-implant related chorio-retinal cobalt toxicity.

A 39-year-old female with elevated serum cobalt levels from her bilateral hip prostheses presented with a 3-week history of blurred vision in her left eye. Optical coherence tomography revealed patchy degeneration of the photoreceptor-retinal pigment epithelium (RPE) complex. The lesions were hypofluorescent on indocyanine green angiography. We postulate that this is a case of implant-related chorio-retinal cobalt toxicity.

Effect of Amiloride to Retinal Toxicity Induced by Tissue Plasminogen Activator

PURPOSE: The effects of amiloride on cellular toxicity caused by tissue plasminogen activator (tPA) in mouse primary retinal cells were investigated. METHODS: Primary retinal cell cultures were maintained using glial conditioned medium. Commercial tPA and L-arginine were added, and the level of cyclic guanosine monophosphate (cyclic-GMP) in the culture supernatant was assessed using an ELISA assay. We measured the cell viability of cultured retinal cells pretreated with three different concentrations of amiloride (1, 10, and 100 microm) in addition to commercial tPA or L-arginine treatment. RESULTS: After exposing the cultured mouse retinal cells to tPA plus L-arginine or L-arginine alone, cyclic-GMP concentrations were 61.9 +/- 5.1 pmole/mL and 63.1 +/- 6.1 pmole/mL, respectively. However, the control group had a significantly lower concentration of cyclic-GMP (37.2 +/- 3.4 pmole/mL, p < 0.01). The cyclic GMP-dissolved solution did not cause retinal cell death. In the control group and the group treated with 1 microm amiloride and tPA containing L-arginine, the cell viability was 43.7% and 44.5%, respectively. However, cell viability increased to 70.6% with 10 microm amiloride and 78.4% with 100 microm amiloride (p = 0.015). CONCLUSIONS: L-arginine increases intracellular cyclic-GMP and may give rise to retinal cells through this mechanism. In addition, amiloride in concentrations greater than 10 microm protects against L-arginine-induced retinal cell death.

Consideraciones actuales sobre la toxicidad retiniana por cloroquina y sus derivados / Present remarks on retinal toxicity caused by chloroquine and its derivatives

La cloroquina y la hidroxicloroquina son drogas que se utilizan en el tratamiento de enfermedades reumáticas. Desde la descripción en 1959 de la retinopatía que pueden ocasionar, se produjo una importante disminución de su uso. La hidroxicloroquina se considera la de menor toxicidad entre ellas, no obstante han sido reportados casos de enfermedad retiniana en personas que han empleado esta droga durante mucho tiempo. El propósito de este artículo es actualizar sobre la efectividad de protocolos de despistaje para la detección de afectación retiniana en consumidores de cloroquina y sus derivados. Se realizó una búsqueda automatizada de artículos científicos relacionados con el tema, en PUBMED e HINARI, que resultó en 27 publicaciones realizadas durante los años 1999-2010. Las investigaciones para la detección de la retinopatía han estado sujetas a controversias. No hay consenso entre reumatológos y oftalmólogos acerca de cómo debe monitorizarse y diagnosticarse la toxicidad ocular. Las pruebas más comunes para descubrir la toxicidad han sido: la agudeza visual, los campos visuales, el test de visión de colores, electrorretinografía estándar y la angiografía fluoresceínica. Estudios recientes demuestran que el electrorretinograma multifocal parece ser muy útil en esta entidad, por lo que pudiera ser empleado en la detección de daño retinal subclínico. Esto sería de inestimable valor para evitar el déficit visual por el efecto tóxico del fármaco. La frecuencia de evaluaciones debe ser individualizada en cada paciente, dependiendo de la presencia o no de factores de riesgo al inicio del tratamiento y la dosis diaria del medicamento.

Chloroquine and hydroxychloroquine are drugs used in the treatment of rheumatic diseases. Since the description of the retinopathy that theycould cause in 1959, there was a significant reduction in their use. Hydroxychloroquine is considered the least toxic among them; however, there have been reported cases of retinal disease in users of the drug for a long time. The objective of this article is to present updating on the effectiveness of screening protocols for the detection of retinal disease in people taking chloroquine and its derivatives. A computerized search for scientific articles related to the subject was made in Hinari and PUBMED, which resulted in 27 publications during the 1999-2010 period. Research for the detection of retinopathy has been controversial; there is no consensus between rheumatologists and ophthalmologists on how to monitor and diagnose ocular toxicity. The most common tests to discover toxicity were visual acuity, visual fields, the color vision test, standard electroretinography and fluorescein angiography. Recent studies showed that the multifocal ERG seems to be very useful to evaluate the toxicity derived from chloroquine, so it could be used in the detection of subclinical retinal damage. The latter would be of great value to avoid the visual impairement by the toxic effect of the drug. The frequency of evaluations should be customized for each patient, depending on the presence or absence of risk factors at baseline and the daily dose of the drug.

Retinal Toxicity of Intravitreal Tissue Plasminogen Activator on Submacular Hemorrhage

PURPOSE:To present the clinical feature of retinal toxicity of intravitreal tissue plasminogen activator which was used for treatment of submacular hemorrhage. CASE SUMMARY: An intravitreal injection of tPA (100 microg) with C3F8 gas tamponade (0.2 cc) was given to treat the submacular hemorrhage in a patient with ARMD. The therapeutic effect was measured by visual acuity, slit lamp examination, indirect funduscopy and fluorescein angiogram. Three months after the operation, the hemorrhage was decreased but a pigmentary change was observed on the peripheral retina. After 8 months, the submacular hemorrhage completely reabsorbed but the peripheral pigmentary change had increased. Ten months later, the retinal pigmentary change was observed on the entire retina except the posterior pole. The fluorescein angiogram showed peripheral hyperfluorescene of the retina due to window defect from the pigmentary change but no leakage was detected. The electroretinogram showed reduced amplitude in the right eye. CONCLUSIONS: Intravitreal tPA injection of 25 to 100 microg with pneumatic displacement is typically used for the treatment of submacular hemorrhage. However, there is no established safety dose of tPA for use in human eyes. In the present study, 100 microg of tPA was used and retinal toxicity was noted. Establishing a safety dose of tPA to prevent dosage dependent complications is necessary.

Retnal Toxicty of Intravitreal Tissue Plasminogen Activator with C3F8 Injection in Rabbit Eyes

PURPOSE: To determine the concentration at which a mixed injection of tissue plasminogen activator (tPA) and C3F8 gas is toxic, we studied the histopathological changes in the rabbit retina. METHODS: Only tPA was injected into the right vitreous cavities of 18 normal pigmented rabbits at doses of 25 micro gram/0.1mL, 50 micro gram/0.1mL, and 100 micro gram/0.1mL, 6 rabbits per dosage. In the same rabbits, tPA and C3F8 (0.2cc) were simultaneously injected into the left vitreous cavities at doses of 25 micro gram/0.1mL, 50 micro gram/0.1mL, and 100 micro gram/0.1mL. All of the eyes were examined by slit lamp biomicroscopy and indirect ophthalmoscopy at 5, 10, and 15 days after the injection, and then they were enucleated for histopathological evaluation. RESULTS: Retinal pigmentary alterations were centered around the injection site 3 days postoperatively in the eyes receiving doses of 50 micro gram/0.1mL or greater. On light microscopy(LM), the involved areas showed vacuolization in the photoreceptor elements and the inner nuclear layer(INL) at a dose of 25 micro gram/0.1mL at postoperative 5 days and the vacuolar changes disappeared at postoperative 15 days. But at doses of 50 micro gram/0.1mL or greater, loss, contracture, and vacuolization of the photoreceptor outer segment (POS) and vacuolization of INL were noted at postoperative 15 days. On LM, at a dose of 25 micro gram/0.1mL, the involved areas showed vacuolization in POS and mitochondrial swelling of the photoreceptor inner segment (PIS) at postoperative 5 days. The mitochondrial swelling of PIS disappeared at postoperative 15 days. However, at doses of 50 micro gram/0.1mL or greater, loss and contracture of POS and mitochondrial swelling of PIS were noted at postoperative 15 days. The retinal damage from simultaneous injection of tPA and C3F8 at doses of 25, and 50 micro gram/0.1mL was equal to or less than that of only tPA injection, whereas at a doses of 100 micro gram/0.1mL the damage was greater. CONCLUSIONS: At doses of 50 micro gram/0.1mL or greater, irreVersible retinal toxicity was noted histopathologically in rabbit eyes. At doses of 25, and 50 micro gram/0.1mL, the degree of retianl damage did not seem to be affected by whether C3F8 was injected concomitantly or not.

The Effect of Intravitreal Melatonin on Rabbit Retina

PURPOSE: To investigate the effect of intravitreal melatonin on retina in rabbit. METHODS: In four pigmented rabbit, melatonin was intravitreally injected 100 mu g/0.1 ml, 300 mu g/0.1 ml concentration in left eye, DMSO was injected in right eye as control. we examined gross fundus finding and electroretinogram and then light and electronic microscopic findings at 24 hours and 1 week with both eye. RESULTS: intravitreally melatonin injected eye at 100 mu g/0.1 ml, 300 mu g/0.1 ml concentration and control eye at 1 day and 1 week, significant difference was not shown in gross fundus finding, electroretinogram, light and electronic microscopic finding. Additionally edema, toxic effect change was not found in retina. CONCLUSIONS: Intravitreally injected melatonin has not influenced on retina grossly, histologically, physiologically at 100 mu g/0.1 ml and 300 mu g/0.1 ml concentration. Further study is required about toxic effect of melatonin over 300 mu g/0.1 ml concentration and clinical usefulness of melatonin in retina.

Experimental Studies on the Retinal Responses to Intravitreal Perfluorocabon Liquids

Perfluorocarbon liquids (PFCLs) are useful tools during vitreous surgery for complicated retinal detachments. Generally, these liquids are used as short-term vitreous replacement without retinal toxicities. But long-term tolerance of intraocular fluorochemicals is not established. We evaluated long-term tolerances to intraocular perfluorophenanthrene(Vitreon) or perfluorodecalin(DK-line) in the rabbit retina for a period of up to 3 months. Three days after C3F8 gas-compression of the vitreous, 1.2ml of highly purified PFCLs were injected into 26 rabbit eyes. Control eyes received same volumes of balanced salt solution. Eyes were examined by indirect ophthalmoscopy and light and electron microscopy. Clinically PFCLs were emulsified and dispersed into small bubbles after 2-3 weeks. Mild posterior subcapsular cataracts and vitreous opacities were observed after long-term retention of PFCLs. Histopathologically, at 1 week after surgery, several epiretinal macrophages were present in both groups. Focal disarrangements of photoreceptors were observed in perfluorodecalintreated group. At I month after surgery, protrusion of Muller cell, dropdown of photoreceptor nuclei, loss of photoreceptors, outer and inner segments and retinal pigment epithelial hypertrophy were observed. In perfluorodecalin-treated group, atrophy in outer nuclear layer and thinning of all the retinal layers occurred. At 3 months after surgery, small oil-like droplets were scattered throughout the retinal layers and retinal pigment epithelium in perfluorodecalin-treated group. These findings were almost totally confined to the lower part of retina that has been long-term contact with the liquids. Our findings suggest that perfluorodecalin is more toxic to the retina than perfluorophenanthrene. Both liquids are not adequate for long-term vitreous replacement, but may be useful for short-term intraoperative use.

Histological Changes of the Retinal Following High dose Intravitreal Ganciclovir Injection in Rabbit

Authors evaluated the retinal toxicity of high dose (2mg/0.1ml, 4mg/0.1ml) intravitreal ganciclovir injection in rabbit eye with light microscopy and electron microscopy. The results were as follows: In twenty-four hours after 2.0mg/0.1ml intravitreal injection group, edema of outer cells in inner nuclear layer were visualized under electron microscopy. These findings were disappeared after 3 days. In 4.0mg/0.1ml intravitreal injection group, edema of outer cells in inner nuclear layer were visualized at 24 hours after injection. Edema of outer cells in inner nuclear layer and axonal swelling of outer plexiform layer and upper border cells of outer nuclear layer were demonstrated at third and seventh day after injection. We observed more severe changes at seventh day than third day, and fragmentation of inner and outer segments in photoreceptor cells and presence of macrophage corresponding site of subretinal space. So, it suggests that 4.0mg/0.1ml intravitreal ganciclovir injection has mild reversible retinal toxicity.

Toxicity of Ciprofloxacin in Vitreous Infusion Fluid on Rabbit Retina

To investigate the retinal toxicity of ciprofloxacin on retina, 23 New Zealand white rabbits received vitrectomy with intravitreal infusion that contain of 1 g/ml, 2 g/ml, 5 g/ml, 10 g/ml, and 25 g/ml of ciprofloxacin(20 eyes) or balanced salt solution(BSS) only(3 eyes). In transmission elctron microscope, no disintegration of all retinal layers and slightly irregular pattern of disc of outer segment of rod were observed in 1, 2 and 5 g/ml of ciprofloxacin groups at 14 days postinfusion. In concentration of 10 g/ml or greater, retina showed destroyed inner and outer segment of the photoreceptor cells, pyknotic nuclei in the outer nuclear layer, lucent vacoules and pigment granules in apical cytoplasm of the retinal pigment epithelium(RPE), loss of photoreceptor outer segment-RPE integration. This study suggest that infusion with 5 g/ml or less of ciprofloxacin may be safe when used in the treatment of bacterial endophthalmitis.

Safety of Intravitreal Ciprofloxacin in Phakic Rabbit Eyes Determined with Electroretinography

This study was conducted to determine the safe intravitreal dosage of ciprofloxacin. Twenty-four phakic eyes of New Zealand pigmented rabbits were used. Each group(4 eyes) received midvitreal ciprofloxacin of 100, 200, 400, 600, 800 micro gram in 0.1ml BSS Plus, or 0.1ml BSS Plus only as control. We evaluated retinal function by measuring the electroretinograms for a graded series of flash intensities and fitting b-wave amplitudes to the Naka-Rushton equation. At a dose of greater than 600 micro gram, Rmax decreased signifantly and log K increased signifantly. N-value decreased slightly. B-wave amplitude decreased as a toxic response of intravitreal ciprofloxacin in a dose dependent manner, and this response was best detected using lower luminance stimuli. Lower luminance electroretinography revealed a significant decrease in b-wave amplitude in eyes injected with a dose of 400 micro gram or more. We concluded that 200 micro gram will be the safe intravitreal dosage of ciprofloxacin in phakic rabbit eyes.

Experimental Evaluation of Intravitreal Perfluorodecalin and Silicone Oil in the Rabbit as a Long-acting Intraocular Tamponade

Perfluorodecalin, which is one of the perfluorocarbon liquids, is not established safety in use of long-acting intraocular tamponade. Therefore, to determine its safety we injected it alone and combined with silicone oil into the vitreous of vitrectomized eyes. We evaluated the changes of the fundus, electroretinogram, histopathology as light and electron microgragh after lensectomy and vitrectomy in pigmented rabbits periodically. In rabbits replaced with perfluorodecalin alone, fundus showed mild proliferative vitreoretinopathy and micrographs showed the destruction of the inner and outer segments of the photoreceptors. In rabbits replaced with perfluorodecalin and silicone oil, fundus showed more severe proliferative vitreoretinopathy than perfluorodecalin alone and micrographs showed the destruction of the entire retina. In electroretinogram, the amplitude was decreased markedly. So, it is considered that perfluorodecalin was not tolerant in case of longacting intraocular tamponade and also perfluorodecalin combined with silicone oil developed severe proliferative vitreoretinopathy.

Safety of intravitreally injected ciprofloxacin in phakic rabbit eyes

This study was designed to determine the maximal safe drug concentration of intravitreal ciprofloxacin in phakic rabbit eyes. Twenty-two eyes of New Zealand pigmented rabbits received midvitreal ciprofloxacin of 100, 200, 400, 600 or 800 microgram in BSS Plus, or BSS Plus only. Retinal toxicity was dose-dependent as determined with electroretinography, light microscopy, and transmission electron microscopy. At a dose of greater than 400 microgram, disorganization of the outer segments was a main pathological finding in transmission electron microscopy. We evaluated retinal function by measuring the electroretinograms for a graded series of flash intensities and by fitting electroretinogram b-wave amplitudes to the Naka-Rushton equation. At a dose of greater than 600 microgram, Rmax was significantly decreased and log K was significantly increased. N-value tended to decrease. A decrease of b-wave amplitudes caused by retinal toxicity could be detected very sensitively with lower luminance stimuli. Determination of retinal toxicity with lower luminance electroretinography revealed a significant decrease of b-wave amplitudes at a dose of greater than 400 microgram. We concluded that a safe dose of intravitreal ciprofloxacin in phakic rabbit eyes was 200 microgram in phakic eyes.

Effect of Intracameral Mitomycin-C Irrigation on ERG in Rabbit

Mitomycin-C(MMC) has been increasingly used as adjunct chemotherapy during glaucoma filtering surgery in order to increase the success rate, because of its ability to inhibit the proliferation of fibroblast. Although MMC demonstrates toxic effects in the anterior segment of the eye, few studies on its retinal toxicity have been reported. Therefore, this study was performed to investigate the retinal toxicity of MMC in the rabbit after intra cameral irrigation. After anesthesia, 1 ml of MMC(40 mg/ml) was intracamerally irrigated in right eye and 1ml of balanced salt solution(BSS) was used as control in the left eye. The electroretinogram was checked before, 2 and 7 days after intracameral MMC irrigation. The fundus examination and histopathology by light microscopy and transmission electron microscopy were performed at 7days after MMC irrigation. On electroretinogram, scotopic b-wave amplitude in MMC irrigated eye was significantly decreased 7 days after irrigation as compared with BSS irrigated eye. The retina in MMC irrigated eye was normal on the fundus findings and histopathology by light microscopy and transmission electron microscopy 7 days after irrigation. This findings suggest that intracameral irrigation of MMC may induce the functional disturbance rather than structural alteration of retina.

Two Cases of Ischemic Retinopathy due to Intravitreal Gentamicin Toxicity after Vitrectomy

Retinal toxicity secondary to intravitreal injection of gentamicin for the purpose of prophylaxis or treatment of endophthalmitis was reported infrequently and it was thought to be caused by an error in the intravitreal injection technique or by faulty dilution of gentamicin. After vitrecotomy, we experienced two cases of ischemic retinopathy secondary to intravitreal injection of gentamicin for prevention of endopthalmitist.