A Case Report Illustrating the Spontaneous Vision Recovery After Inadvertent Central Descemetorhexis During Anterior Capsulotomy.

PURPOSE: To demonstrate an unusual mechanism of iatrogenic, central descemetorhexis (DMR) during cataract surgery and subsequent rare spontaneous visual acuity improvement within 2 months after inadvertent surgical complication. PATIENTS AND METHODS: A 81 year old woman underwent cataract surgery complicated by the loss of a 4.8X4.75 mm diameter central area of Descemet membrane. Perioperative video recording documented the DMR formation during continuous curvilinear capsulorhexis creation. RESULTS: Postoperatively, severe corneal edema with folds in the remaining Descemet membrane were observed. The patient was managed conservatively. The corneal edema gradually resolved over 2 months with improving of visual acuity from counting fingers to 20/20. CONCLUSION: Unlike Descemet membrane detachment, descemetorhexis is a rare complication after intraocular surgery. The case report identifies a previously unknown mechanism of DMR formation during anterior capsulotomy creation. Loss of Descemet membrane may be managed conservatively in an otherwise healthy cornea with good final visual outcome without the need for surgical intervention.

Long-term results of pars plana vitrectomy as an anti-inflammatory therapy of pediatric intermediate uveitis resistant to standard medical treatment.

PURPOSE: To evaluate the efficacy of pars plana vitrectomy (PPV) as an anti-inflammatory therapy in pediatric recurrent intermediate uveitis. METHODS: A retrospective study evaluated the long-term results of PPV indicated for intermediate uveitis with a mean observation period of 10.3 years (range 7-15.6 years) in 6 children (mean age 8 years, range 6-12 years). Pars plana vitrectomy was performed on 10 eyes in the standard manner and was initiated by vitreous sampling for laboratory examination. Data recorded were perioperative or postoperative vitrectomy complications, anatomic and functional results of PPV, and preoperative and postoperative best-corrected Snellen visual acuity. RESULTS: No perioperative or postoperative complications were observed. Bacteriologic, virologic, mycotic, and cytologic analysis of the vitreous was negative in all tested children. Five eyes were subsequently operated on for posterior subcapsular cataracts. An average preoperative visual acuity of 0.32 improved to an average postoperative visual acuity of 0.8. CONCLUSIONS: In the case of systemic immunosuppressive treatment failure in pediatric uveitis, particularly in eyes with cystoid macular edema, we recommend PPV relatively early.

Retinal toxicity after repeated intravitreal carboplatin injection into rabbit eyes.

BACKGROUND: The aim of this study was to assess retinal toxicity in a rabbit model after carboplatin delivered as repeated transcorneal intravitreal injection, in order to determine the highest possible safe dose for use in human retinoblastoma "seeding" tumor chemotherapy. METHODS AND RESULTS: We used six albino rabbits in an in vivo experiment and injected 0.008 mg of carboplatin intravitreally (iv) 4 times at two-week intervals. 0.08 mL saline was injected into the left eye. We recorded electroretinograms (ERGs) before the first carboplatin injection and after the fourth injection. Platinum concentration was measured 1 h after the fifth additional injection. We found reduced dark-adapted b-wave amplitudes and, light-adapted b-wave and a-wave amplitudes. The differences between right and left eyes was significant but we found no histopathologic retinal changes. CONCLUSIONS: 0.008 mg of carboplatin is probably the highest possible safe dose for the treatment of retinoblastoma patients. Questionable is direct extrapolation of retinal toxicity from the rabbit eye model to the human eye.

Topotecan vitreous and plasma levels and retinal toxicity after transcorneal intravitreal delivery in healthy albino rabbits: alternative retinoblastoma treatment.

AIM: To determine intravitreal and plasma concentrations and retinal toxicity after transcorneal intravitreal injection of 1 µg and 2 µg of topotecan (Hycamtin). METHOD: Twelve healthy albino rabbits were included in this in vivo experiment. Six anesthetized albino rabbits received a single transcorneal intravitreal injection of 1 µg (group A) or 2 µg (group B) of topotecan. Vitreous and blood samples were collected until 168 h. Left eyes were treated with the same volume of saline. Plasma and vitreous levels of topotecan were determined by high-performance liquid chromatography. Area under the plasma concentration time curve (AUC) was calculated using trapezoidal rule. Clinical evidence of toxicity was classified into four grades according to anatomical structures. Electroretinograms (ERGs) were recorded. RESULTS: Time to maximum concentration was observed up to 2 h after drug injection in group A whereas up to 1 h in group B. Low levels of topotecan were detected in plasma in both groups and in the vitreous humor of the contralateral eye in group B. Topotecan levels (mean vitreous AUC in group A 2.55 µg/mL.h and in group B 5.338 µg/mL.h) were detectable up to 6 h in both groups. We observed following structural changes in rabbit eyes: corneal vascularization, cataract, hemophthalmus, choroidal edema and focal retinal atrophy. Abnormal ERGs were obtained. CONCLUSION: Our findings proved that transcorneal intravitreal administration of 1 µg and 2 µg of topotecan results in potentially cytotoxic intraocular concentrations. More studies are needed to establish the safety of topotecan for retinoblastoma in children.

Intravitreal carboplatin concentration and area under concentration versus time curve after intravitreal and periocular delivery.

PURPOSE: To determine platinum (Pt) concentrations and area under the concentration versus time curve (AUC) of the vitreous humor after periocular or transcorneal intravitreal administration of carboplatin in rabbits. METHODS: Eighteen albino rabbits were included in an in vivo experiment. Each animal received a single dose of either 30 mg of carboplatin by periocular injection (POI30 group: n = 6) or 15 mg by periocular injection (PI15 group: n = 6), or 0.05 mg by transcorneal intravitreal injection (TII group: n = 6), respectively, into the right eye. Vitreous humor from the right eyes and plasma samples were collected post dose at 1, 2, 6, 24, 48, 168, and 336 hours or 448 hours, respectively. Flameless atomic absorption spectroscopy was employed to analyze total platinum concentrations in blood and vitreous humor. AUC was calculated using the trapezoidal rule. RESULTS: Pt concentration was mostly < 1 mg/L (0-3.15 mg/L) in the vitreous humor samples and > or = 2 mg/L (2.33-7.3 mg/L) in the blood samples 1 hour after administration in POI groups. Markedly higher Pt concentrations were found 1 hour after intravitreal (TII) administration (10.285-66.759 mg/L) and decreased below 1 mg/L no less than 168 hours after administration. The mean AUC for Pt in vitreous humor was significantly lower (p = 0.0001) after both POI30 and P0I15 administration compared to TII route (8.955 +/- 2.464 mg/L/min). CONCLUSIONS: These findings proved that intravitreal carboplatin delivery enables the achievement of relatively stable concentrations and AUC of platinum in the rabbit vitreous humor. This moreover suggests that transcorneal intravitreal delivery of carboplatin aiming to treat retinoblastoma vitreous seeding is a promising mode of chemotherapy.

An adsorptive transfer technique coupled with brdicka reaction to reveal the importance of metallothionein in chemotherapy with platinum based cytostatics.

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.