The effect of minoxidil on keratocyte proliferation in cell culture

PURPOSE

To determine if minoxidil inhibits keratocyte proliferation in a nontoxic manner.

METHODS

Rabbit keratocytes were cultured in Eagle's minimum essential medium supplemented with fetal bovine serum. Minoxidil varying in concentration from 10(0) to 10(3) micrograms/ml was added to the culture medium and incubated for 7 days. The cultures were inspected for morphologic appearance and the cell number was determined at 1, 3 and 7 days after the addition of minoxidil. After 7 days of incubation, minoxidil was withdrawn from the cell culture medium and the cells were examined 3 and 7 days thereafter. In addition, a nonradioactive cytotoxic assay was performed to determine if toxicity is associated with the presence of minoxidil.

RESULTS

Minoxidil inhibited keratocyte proliferation in a dose-dependent fashion. 29% of control growth was achieved when keratocytes were cultured for 7 days in 10(3) micrograms/ml, whereas 82% control growth was achieved when keratocytes were cultured in 10(2) micrograms/ml of minoxidil. Intermediate concentrations between 10(2) and 10(3) micrograms/ml produced a linear decline in cell counts in a dose-dependent fashion. The concentration of minoxidil required for 50% control growth at 7 days extrapolated from the dose-response curve was 600 micrograms/ml. Upon withdrawal of minoxidil, cell counts returned to baseline for concentrations of 10(2) micrograms/ml or less. Phase contrast microscopy revealed that the presence of minoxidil was associated with intercellular separation, enlargement of cell bodies and elongated processes. After the withdrawal of minoxidil, the cells in all media reassumed the morphological features of normal keratocytes which included a regular fusiform shape and extensive intercellular contact. The nonradioactive cytotoxic assay revealed the lack of cytotoxicity at all concentrations of minoxidil based on a lack of lactate dehydrogenase release.

CONCLUSIONS

Minoxidil inhibits keratocyte proliferation by a nontoxic mechanism. It might be particularly useful for modulating corneal wound healing following excimer laser photorefractive keratectomy.

A new look at dry eye disease and its treatment

This review examines the impact of moderate to severe dry eye disease on daily life and medical-resource utilization. The results suggest that current treatment paradigms can lead to unacceptable costs in both quality of life and progressive use of healthcare resources. Evidence linking this disease to T-cell-mediated inflammatory processes lays the foundation for understanding the clinical benefits of topical cyclosporine, an immunomodulatory and anti-inflammatory agent.

The effect of propranolol versus placebo on resident surgical performance

PURPOSE

To determine whether propranolol can decrease surgical tremor and anxiety in residents performing ocular microsurgery without impairing patient or physician safety.

METHODS

In this randomized, double-masked, crossover study, 5 third-year ophthalmology residents ingested a capsule containing either propranolol, 40 mg, or placebo 1 hour prior to performing ophthalmic microsurgery. All residents were healthy men under age 30 years. Prior to commencement of the study, all participants had successfully been administered a test dose of propranolol without side effects. The study took place over a 10-week period. At the conclusion of each case, both the resident and attending surgeon observer independently completed a form grading, on a sliding scale: (1) amount of overall tremor; (2) amount of tremor during placement of the first 3 sutures after lens or nucleus extraction; (3) anticipated difficulty of the case; (4) actual difficulty with the case; and (5) anxiety (surgeon only). In addition, the type of procedure performed, complications encountered, and surgeon side effects were recorded. The data were analyzed with a 2-way analysis of variance for unbalanced data.

RESULTS

A total of 73 surgical cases were performed; the surgeons were administered propranolol for 40 cases and placebo for 33. As judged by the resident surgeon, there was a highly significant effect of propranolol in decreasing anxiety (P = .0058), reducing surgical tremor overall (P < .0001), and reducing tremor while placing the first 3 sutures following lens extraction (P < .0001). There was no treatment-by-surgeon interaction for any of the measures. Complications and difficulty of the case, as judged by both the resident and attending surgeons, were not significantly different in the propranolol versus placebo groups (P > .05). There were no side effects reported or observed in any of the surgeons.

CONCLUSIONS

Propranolol, 40 mg, administered 1 hour prior to surgery, significantly decreases tremor and anxiety in the surgeon without untoward effects to the surgeon and the patient. However, it is unknown whether decreased tremor and anxiety improved surgical outcome.

Preparation of pH-adjusted local anesthetics

Characteristics of alkalinized local anesthetics are poorly described with regard to stability and precipitation. Current fixed-volume methods of alkalinization often result in unstable, precipitated solutions of unpredictable pH. We determined a stable, nonprecipitating, anesthetic mixture and used it in a randomized double-blind crossover study of 21 patients to evaluate alkalinized anesthetic solutions in reducing pain on injection. Our solution significantly reduced pain associated with retrobulbar injection (analysis of variance, P = .0362) but not that associated with Nadbath injection. Fixed-volume alkalinization is not recommended because complications can result with the use of precipitated anesthetics.

Effectiveness of apraclonidine and acetazolamide in preventing postoperative intraocular pressure spikes after extracapsular cataract extraction

We studied the effectiveness of two prophylactic agents in controlling early postoperative intraocular pressure (IOP) increases after cataract surgery. Fifty-four nonglaucomatous patients received either topical 1% apraclonidine, one drop before and after surgery, or sustained-release acetazolamide, 500 mg, or no medication at the completion of planned extracapsular cataract extraction (ECCE). Mean baseline IOPs were similar among patients randomized to the apraclonidine, acetazolamide, and control groups: 15.29 mm Hg, 15.33 mm Hg, and 14.26 mm Hg, respectively. At 3 hours postoperatively, IOPs were significantly lower in the apraclonidine group (11.13 mm Hg, P = .035), nonsignificantly lower in the acetazolamide group (13.3 mm Hg, P = .17), and significantly increased in the control group (21.32 mm Hg, P = .003). One eye in the apraclonidine group and six in the control group had IOPs greater than 30 mm Hg. At 24 hours, the only statistically significant difference was in the control group, whose mean IOPs remained elevated (21.83 mm Hg, P = .0008). One eye in the apraclonidine group, two in the acetazolamide group, and five in the control group had IOPs greater than 30 mm Hg. We found a significant early IOP reduction with apraclonidine given topically preoperatively and at the completion of planned ECCE.

Intravitreal U75412E: a new free radical scavenger

Free-radical-mediated tissue damage is thought to be involved in a multitude of ophthalmic pathologies. Therefore, drugs that scavenge free radicals may find wide clinical application. A new chemical class of antiinflammatory agents, the 21-aminosteroids, has been developed as free radical scavengers. These agents are thought to inhibit lipid peroxidation and prevent the release of free arachidonic acid from injured cell membranes. In the present study, we investigated the intraocular toxicity of one of the 21-aminosteroids, U75412E. Intravitreal doses of up to 0.1 mg of U75412E were nontoxic to rabbit ocular tissues.

Intraocular penetration of topical tissue plasminogen activator

Fifty-eight eyes of 31 anesthetized rabbits received one drop of proparacaine hydrochloride, 0.05%, and two drops of tissue plasminogen activator (tPA) separated by 5 minutes. Four eyes of two additional rabbits had epithelial defects created before drug delivery. Tissue plasminogen activator in multiple doses was given to eight eyes of four other rabbits. We used this dosing regimen to investigate the effect of topical tPA on anterior chamber fibrin clots in three rabbits. A two-site enzyme-linked immunosorbent assay test was used to measure tPA levels in the aqueous samples, obtained by paracentesis in each eye. Of 53 eyes treated with the original dosing regimen, 21 (40%) had detectable tPA aqueous levels. Blood and aqueous from eyes of untreated control rabbits, contralateral control eyes of treated rabbits, and eyes with epithelial defects had nondetectable tPA. Multiple tPA drop dosing resulted in 75% of aqueous samples with detectable tPA and a higher average tPA concentration than the original dosing regimen. Eyes treated with tPA showed a significantly faster resolution of anterior chamber fibrin clots than did control eyes.

Aminocaproic acid versus prednisone for the treatment of traumatic hyphema. A randomized clinical trial

One hundred twelve patients who sustained hyphema after blunt trauma were enrolled in a double-blind randomized clinical trial to determine the relative efficacies of aminocaproic acid (Amicar) and systemic prednisone for reducing the rate of secondary hemorrhage. Fifty-six patients received an oral dosage of 50 mg/kg of aminocaproic acid every 4 hours for 5 days, up to a maximum of 30 g daily, and 56 patients received an oral dosage of 40 mg of prednisone daily (adjusted for weight) in two divided doses. Placebo pills and liquids were given to each patient to mask the treatment schedules. There were no statistically significant differences between the patient populations for any demographic or clinical characteristic (e.g., visual acuity, intraocular pressure [IOP], initial hyphema size) measured in the study. Blacks comprised 53% of the study population, and the mean age of the patients was 23.5 years. Four patients in each of the treatment groups experienced a secondary hemorrhage; the rebleed rate was 7.1% in each group.

Ocular toxicity of experimental intravitreal itraconazole

We investigated itraconazole, a new triazole antifungal agent that poorly penetrates ocular tissues after oral administration. We injected itraconazole in doses from 10 to 100 micrograms dissolved in 100% dimethyl sulfoxide into the eyes of New Zealand rabbits. Ocular toxicity studies performed five weeks after administration showed no substantial retinal or histopathologic changes in eyes injected with either 100% dimethyl sulfoxide or 10 micrograms of itraconazole. Higher doses caused focal areas of retinal necrosis. Our results indicated that intravitreal doses of 10 micrograms or less of itraconazole may be beneficial in the treatment of fungal endophthalmitis.

Achromobacter xylosoxidans corneal ulcer in a therapeutic soft contact lens wearer

Achromobacter xylosoxidans is an opportunistic organism that is usually seen in immunocompromised or immunosuppressed patients. It is an aerobic gram-negative rod, often confused with other more commonly seen gram-negative bacteria such as Pseudomonas aeruginosa. The organism is usually sensitive to extended spectrum penicillins such as carbenicillin and usually resistant to aminoglycosides and first generation cephalosporins. We wish to describe a corneal ulcer from A. xylosoxidans that developed in a patient wearing a therapeutic soft contact lens. The patient did not have a preexisting microbial keratitis and was not receiving corticosteroid therapy.

Ocular toxicity after intravitreal injection of terconazole

Terconazole, a new triazole antifungal agent, was injected intravitreally in doses ranging from 10 to 100 micrograms dissolved in dimethyl sulfoxide (DMSO) 60% into the eyes of New Zealand rabbits. Three control eyes received only DMSO. The eyes were evaluated with biomicroscopy, indirect ophthalmoscopy, electroretinography, and histopathologic examination. From these data, it was determined that an intravitreal injection containing a concentration of 10 micrograms/0.1 mL of terconazole is not toxic to the rabbit eye.

Toxicity of intravitreal oxiconazole

Oxiconazole, a new imidazole derivative, has a broad antifungal spectrum in vitro and in vivo. Adult New Zealand white rabbits were injected intravitreally with doses ranging from 10 to 100 micrograms of this drug. Eyes were evaluated with preoperative and postoperative biomicroscopy and indirect ophthalmoscopy, electroretinography, and light microscopy. From these data, it was determined that an intravitreal injection containing a concentration of up to 100 micrograms per 0.1 milliliter of oxiconazole was nontoxic to the rabbit eye.

Retinal toxicity of intravitreal ethyldeoxyuridine and zinc

We investigated the toxicity of intravitreal zinc sulfate, zinc gluconate, and ethyldeoxyuridine (EDU) in albino rabbits. Various concentrations of EDU were added to the infusion solution during pars plana vitrectomy. Retinal changes were observed by light microscopy after intravitreal injections containing 20 micrograms of zinc gluconate, all concentrations of zinc sulfate, and 400 micrograms of EDU. No histologic or electroretinographic alterations occurred with doses of 15 micrograms or less of zinc gluconate or 200 micrograms or less of EDU. When added to the vitrectomy solution, concentrations of 20 micrograms/mL or less of EDU appeared nontoxic to the rabbit retina.

Intravitreal toxicity of bovine cartilage extract (Catrix-S): a biologic response modifier

The intravitreal toxicity of Catrix, a biologic response modifier, was evaluated. A dose of up to 5 mg did not cause a toxic reaction in the ocular structures.

The intraocular penetration and retinal toxicity of teicoplanin

We investigated the intraocular penetration and retinal toxicity of teicoplanin, a relatively new glycopeptide antibiotic with activity similar to vancomycin when used to inhibit staphylococci and other gram positive organisms, particularly Streptococcus faecalia. Topically administered teicoplanin penetrated poorly into the aqueous and vitreous in rabbit eyes. Subconjunctival injection of the drug yielded aqueous levels above the minimum inhibiting concentration (3.1 micrograms/ml) only at one hour after injection. In the vitreous, drug levels were above the mean inhibitory concentration at 30 minutes after the subconjunctival injection, but rapidly declined thereafter. The maximum nontoxic, single-dose, intravitreal injection was 750 micrograms/0.1 ml. Rabbits received 8 micrograms/ml of teicoplanin in an intravitreal infusion solution without demonstrable retinal toxicity.

Intravitreal toxicity of cotrimoxazole

We investigated the intravitreal toxicity of cotrimoxazole (trimethoprim 80 mg and sulfamethoxazole 400 mg/5 ml of injection fluid) in albino rabbits. Eyes injected intravitreally with 1600 micrograms/0.1 cc (reported in trimethoprim concentration) exhibited no histologic or abnormal electroretinographic responses after 14 days. A vitrectomy infusion solution containing 32 micrograms/ml (reported in trimethoprim concentration) produced no toxicity, as demonstrated either by electroretinography or histology. Cotrimoxazole appears to be well-tolerated in rabbit eyes when administered by both intravitreal injection and vitrectomy infusion solution.

Duration of therapeutic levels of intravitreally injected liposome-encapsulated clindamycin in the rabbit

We investigated an intravitreal preparation of liposome-encapsulated clindamycin phosphate to determine the duration of therapeutic levels of the drug in the vitreous cavity. Twenty New Zealand albino rabbits were given an intravitreal injection of 750 micrograms/0.1 mL of encapsulated clindamycin (10 animals) or 800 micrograms/0.1 mL of nonencapsulated clindamycin (10 animals) and then were killed immediately or 6, 12, 24 or 48 hours later. The mean concentration of encapsulated clindamycin in the vitreous at 48 hours was 28.4 micrograms/mL, while that of nonencapsulated clindamycin at 24 hours was 2.3 micrograms/mL. The estimated elimination rate of nonencapsulated clindamycin was 3 hours, compared with approximately 10 hours for the encapsulated preparation. This drug delivery system warrants further investigation for possible use in humans.

Retinal toxicity of combination antiviral drugs in an animal model

We investigated the retinal toxicity of various combinations of four antiviral agents in intravitreal injection and vitrectomy infusion solutions in the rabbit. The nontoxic concentration of each individual agent for intravitreal injection and for vitrectomy infusion has previously been described. Our results support the concept that concentrations of 200 micrograms/0.1 mL of trifluridine, 400 micrograms/0.1 mL of hydroxyacyclovir, 200 micrograms/0.1 mL of acyclovir and 30 micrograms/0.1 mL of vidarabine can be combined for intravitreal injection without toxic retinal effects. Moreover, 60 micrograms/mL of trifluridine, 20 micrograms/mL of hydroxyacyclovir, 40 micrograms/mL of acyclovir and 8 micrograms/mL of vidarabine can be combined in vitrectomy infusion solutions without retinal damage. Further study is needed to determine the full potential of such combinations.

Toxicity of intravitreal injection of fluconazole in the rabbit

Fluconazole is a new bis-triazole derivative proven highly effective against Candida in various animal models. To determine its potential use in exogenous fungal endophthalmitis, 13 New Zealand white rabbits were given intravitreal injections of up to 100 micrograms/0.1 mL of the antifungal. All eyes underwent biomicroscopy, ophthalmoscopy and electroretinography before and after the procedure. No evidence of toxic intraocular effects was detected with these techniques or on light microscopy, performed 8 days after injection. The results suggest that fluconazole has potential application in the treatment of exogenous fungal endophthalmitis.

Intravitreal liposome-encapsulated trifluorothymidine in a rabbit model

Two groups of albino rabbits received an intravitreal injection of liposome-encapsulated trifluorothymidine. One group underwent a clearance study using high-performance liquid chromatography. The results of this study demonstrated a prolonged vitreal drug level within the range of ID50 for many strains of herpesvirus and human cytomegalovirus (CMV) at 28 days after injection. The eyes of another group were evaluated with preoperative and postoperative indirect ophthalmoscopy, electroretinography, and histologic examination. No retinal toxicity was found.

Age and education effects in the diagnosis of attention deficit disorder, residual type in an alcoholic population

Two self-report measures that have been used to screen an alcoholic population for Attention Deficit Disorder, Residual Type (ADD-RT) are the Childhood Symptom Checklist and a listing of the DSM-III criteria. Both measures have evidence supporting their validity as screening instruments for ADD-RT in alcoholics. This study further explores the properties of these instruments by determining whether the age or educational level of alcoholic patients relates to their performance on these measures. No differences were found between the scores of younger and older patients. However, alcoholic patients with more education had fewer DSM-III symptoms of ADD-RT, but did not have fewer symptoms on the Childhood Symptom Checklist. The difference in performance on these two previously consistent measures is noted. Future research might explore the possibility that the DSM-III symptoms of ADD-RT are more sensitive to functional deficits in adults than the Childhood Symptoms Checklist, which asks for symptoms of Attention Deficit Disorder as a child.

Retinal toxicity of ganciclovir in vitrectomy infusion solution

The authors investigated the retinal toxicity of the antiviral agent ganciclovir after its addition to vitrectomy infusion fluid in rabbit eyes. Intravitreal infusion of the drug in concentrations up to 30 micrograms/ml produced no electroretinographic or histologic changes suggestive of retinal toxicity. Ganciclovir in vitrectomy infusion fluid has potential therapeutic benefit in viral retinitis (particularly in cytomegalovirus retinitis) associated with vitreous traction or rhegmatogenous retinal detachment. Based on the median inhibitory doses of ganciclovir against various herpes group viruses and the results of this study, a concentration of 30 micrograms/ml or less of the drug is recommended for vitrectomy infusion solution.

Toxicity of intravitreally administered alpha-interferon

We studied the toxicity of single doses of intravitreally administered alpha-interferon in albino rabbits. Doses of 420,000, 210,000, 105,000, 52,500, and 26,250 units/0.1 cc showed no significant histologic changes by light microscopy or altered retinal function assessed by photopic and scotopic electroretinography.

Intravitreal injection of liposome-encapsulated ganciclovir in a rabbit model

The authors determined the intravitreal clearance of liposome-encapsulated ganciclovir. Liposome-encapsulated ganciclovir (84.1 micrograms/0.1 ml) was injected into the vitreous cavity of New Zealand rabbits, which were killed at 24 hours and 7, 14, and 28 days after injection. Total ganciclovir concentrations in the vitreous, up to 28 days, were higher than ID50 (50% inhibitory dose) for different clinical and laboratory strains of viruses belonging to the herpes simplex family.

Intraocular 9-([2-hydroxy-1-(hydroxymethyl) ethoxy] methyl) guanine levels after intravitreal and subconjunctival administration

Clearance studies in rabbits following intravitreal injection of 400 micrograms of 9-([2-Hydroxy-1-(hydroxymethyl)ethoxy]methyl) guanine demonstrated levels of the antiviral at 60 hours above the in vitro ID50 for several strains of human cytomegalovirus. Intravitreal administration of this new antiviral may have therapeutic application in the treatment of acute retinal necrosis and cytomegalovirus retinitis complicating acquired immune deficiency syndrome (AIDS).

Intraocular acyclovir levels after subconjunctival and topical administration

Substantial levels of acyclovir were detected in the aqueous and vitreous of New Zealand rabbits at various time intervals following subconjunctival injection. Intravitreal penetration of acyclovir after topical application was poor.

A comparison of two dose regimens of epsilon aminocaproic acid in the prevention and management of secondary traumatic hyphemas

Fifty-nine patients who sustained hyphema following blunt trauma were randomly assigned prospectively to either of two dose regimens of epsilon aminocaproic acid (Amicar). Twenty-six took an oral dosage of 50 mg/kg ("half dose") every four hours for five days, up to a maximum of 30 g/day, and 33 patients received 100 mg/kg ("full-dose") every four hours up to a maximum of 30 g/day. Five patients in the full-dose group experienced dizziness, hypotension, and syncope. Half-dose Amicar substantially reduced such serious side effects (P = 0.063), had no adverse effect on the reduced rate of recurrent hemorrhages (P = 0.22), and was more cost effective than the full-dose regimen. When the two patients in the half-dose group receiving 30 g/day of Amicar were deleted, however, the comparison of dizziness and hypotension in the two groups became more significant (P = 0.050). The incidence of nausea and vomiting was approximately the same in both groups (P = 0.52). Serum Amicar levels were within the range of plasminogen inhibition at both dose levels. Prior aspirin ingestion appeared to have no influence on the rate of rebleeding (P = 0.58).

Intravitreal trifluorothymidine and retinal toxicity

Intraocular trifluorothymidine was administered to one group of albino rabbits as an intravitreal injection, and to a second group of albino rabbits in the infusion solution during pars plana vitrectomy. The eyes of both populations were evaluated with preoperative and postoperative indirect ophthalmoscopy, electroretinography, and histologic examination. From these data, it was determined that an intravitreal injection of 200 micrograms/0.1 ml and a vitrectomy solution containing a concentration of 60 micrograms/ml trifluorothymidine were nontoxic to the rabbit eye.

Effects of selected repeated intravitreal chemotherapeutic agents

The toxic effects of repeated intravitreal injections of selected chemotherapeutic agents were studied in female albino rabbits. Three groups of eyes participated in each therapeutic regimen. Agents studied were doxorubicin (dox), 3 and 5 micrograms; 5-fluorouracil (5-FU), 0.375 and 1.0 mg; bleomycin (bleo), 15 micrograms; thiotepa (thio), 12 micrograms; etoposide (VP-16), 150 micrograms; and methotrexate (MTX), 600 mic. Toxicity was evaluated using electroretinography (ERG) in 66% and histopathology in 100% of eyes 5 weeks following the initial injection and at least 2 weeks after the final injection of each series. Eyes receiving 2 doses of dox 3 micrograms showed no toxicity. Eyes receiving 3 or more doses of dox 3 micrograms and those treated with 2 or more doses of dox 5 demonstrated toxicity proportional to the number of doses received. Eyes treated with 5-FU 0.375 or 1.0 mg showed no toxic reaction. Successive intravitreal injections of 5-FU, 0.375 mg and dox 5 micrograms, and 5-FU, dox, and bleo produced no toxicity. Eyes treated with successive intravitreal injections of 5-FU, dox, bleo, and thio displayed decreased ERG response. The addition of VP-16 and MTX resulted in further loss of ERG response and more severe histologic retinal changes.

Clearance of intravitreal 3H-fluorouracil

The clearance of intravitreally administered 5-fluorouracil (5-FU) was studied under five experimental conditions. The same nontoxic dose resulted in similar initial intravitreal concentrations and cleared rapidly from all eyes (approximately 90% clearance within eight hours). Half-life values ranged from 46 to 168 minutes. The longest half-life occurred in aphakic-vitrectomized eyes in which hyaluronic acid (Healon) was substituted for vitreous (168 minutes). A similar half-life was found in normal eyes (150 minutes). The shortest half-life occurred in aphakic-vitrectomized eyes postoperatively (46 minutes). Intermediate half-life values occurred in vitrectomized but phakic eyes postoperatively (67 minutes) and in aphakic-vitrectomized "quiet" eyes (at least two weeks postoperatively) (82 minutes).

In vitro evaluation of cellular inhibitory potential of various antineoplastic drugs and dexamethasone

We evaluated the in vitro cellular inhibitory rates of eight antineoplastic agents and dexamethasone for rabbit retinal pigment epithelial cells and rabbit corneal fibroblasts. Doxorubicin was the most effective chemotherapeutic agent to inhibit cellular proliferation (-90%). Compared to the controls, the percentage variation in cell number for single agents ranged from +26% to -90%. Chemotherapy drugs in combination also were evaluated and found to be not superior to the single agents. Cellular inhibitory rates for combination agents ranged from -34% to -72%. Dexamethasone in the concentrations used did not significantly inhibit or stimulate cellular proliferation.

Evaluation of intravitreal 5-fluorouracil, vincristine, VP 16, doxorubicin, and thiotepa in primate eyes

A single intravitreal dose of 750 micrograms 5 fluorouracil (5 FU) or 5 micrograms doxorubicin were nontoxic to primate eyes. A concentration of 250 micrograms/ml of 5 FU in the vitrectomy infusion fluid in combination with 8 micrograms/ml of thiotepa, with 40 micrograms/ml of VP16 (etoposide), or with either .04 or .02 microgram/ml of vincristine was also well tolerated by the primate eye. 5 micrograms/ml of doxorubicin in the vitrectomy infusion fluid did not cause apparent toxicity to the retina. Toxic effects were noted in eyes receiving 250 micrograms of 5 FU in combination with either .15 or .1 microgram/ml of vincristine.

Toxicity of intravitreal antiviral drugs

Two systemic agents, vidarabine and acyclovir, were tested for ocular toxicity in intravitreal injection and vitrectomy infusion solutions. On the basis of this study we recommend using up to 30 mcg/0.1 ml of vidarabine as an intraocular injection or 8 to 16 mcg/ml in vitrectomy infusion fluid. For acyclovir, 80 mcg/0.1 ml as an intraocular injection or 40 mcg/ml in vitrectomy infusion fluid may be a therapeutic adjunct for managing viral retinitis.

Evaluation of toxicity of intravitreal antineoplastic drugs

We evaluated the toxic and nontoxic doses of eight antineoplastic drugs in the vitreous cavity of rabbits. These drugs may have implications in the prevention of cell proliferation in the vitreous.

Toxicity of antineoplastic drugs in vitrectomy infusion fluids

Twelve antineoplastic drugs were evaluated for their toxicity when used in vitrectomy infusion fluid. These drugs may have implications in the prevention of cellular proliferation inside the eye.