Transconjunctival penetration of mitomycin C

Analysis of the systemic exposure of Mitomycin C used in glaucoma filtering surgery among women in the reproductive age group

PURPOSE

Systemic absorbtion of topically applied mitomycin C (MMC) during trabeculectomy needs to be evaluated to look for any systemic toxicity, which might be a major concern in certain conditions like pregnancy.

METHODS

After obtaining ethical committee clearance, female patients in the reproductive age group undergoing trabeculectomy with MMC were included. Pregnant/lactating patients, patients with any systemic illness were excluded.During trabeculectomy, 0.02% MMC was applied subconjunctivally for 2 minutes and then washed. Blood samples were withdrawn at 1hr, 2hr, 4hr, 8hr, 12hr, and 24hrs after the surgery and analyzed of MMC levels using Liquid chromatography-tandem mass spectroscopy (LCMS-MS).

RESULTS

The mean age of the participants was 29 ± 12 years. MMC was not detected in any of the plasma samples analyzed as it was less than the detection limit (<1.56ng/mL) of the employed LC-MS/MS assay.

CONCLUSION

It can be deduced that the systemic absorption of MMC is negligible or the plasma concentration is less than 1.56ng/ml (1000 times less than the concentration where systemic toxicity was not observed).

Innovations in glaucoma surgery from Dr. Rajendra Prasad Centre for Ophthalmic Sciences

Trabeculectomy surgery is the current standard of care in glaucoma for achieving a low target intraocular pressure if medical therapy is not adequate. Augmentation of trabeculectomy with antimetabolites brought a revolutionary change in the long-term success rates of trabeculectomy, but along with it came a plethora of complications. There still is a big window for therapeutic innovations on this subject. The foremost target for these innovations is to modulate the wound healing response after glaucoma drainage surgery. Achieving the desired balance between long-term success of filtering blebs versus early failure due to scarring of blebs and hypotony due to dysfunctional filtering blebs poses a unique challenge to the ophthalmologists. Alternatives to trabeculectomy such as glaucoma drainage devices and minimally invasive glaucoma surgeries cannot solve the problem of glaucoma blindness in our country, mainly due to their unpredictable results and unfavorable cost-benefit ratio. In this article, we present a summary of our innovations in glaucoma surgery to advance patient care by making it more effective, safer, and economical.

Ocular surface squamous neoplasia as the initial presenting sign of human immunodeficiency virus infection in 60 Asian Indian patients

PURPOSE

To study the importance of routine human immunodeficiency virus (HIV) screening in patients with ocular surface squamous neoplasia (OSSN) and describe their clinical features and management.

METHODS

Retrospective study.

RESULTS

Of 228 cases of OSSN screened for HIV by enzyme-linked immunosorbent assay, 86 (38%) patients were HIV positive. Of these 86 patients, 60 (70%) were unaware of their HIV-positive status prior to HIV screening. These 60 (26%) patients with newly detected HIV-positive status were included in this study. Ocular surface squamous neoplasia was the sole presenting feature of HIV infection in these patients. Mean age at presentation was 41 years. Bilateral involvement occurred in 9 (15%) cases. The mean tumor basal diameter was 11 mm. Orbital involvement was noted in 6 (9%) cases, and intraocular tumor extension occurred in 1 (1%) case. Based on American Joint Committee Classification, T2 (n = 35, 51%) was most common. The primary treatment for OSSN included excision biopsy (n = 52, 75%), topical chemotherapy with Mitomycin-C (n = 5, 7%), extended enucleation (n = 4, 6%), and orbital exenteration (n = 8, 12%). Tumor recurrence occurred in 23% cases during a mean follow-up period of 9 months. On histopathology, invasive squamous cell carcinoma was more common (n = 38, 55%).

CONCLUSION

OSSN was the presenting sign of underlying HIV infection in 26% cases, and 70% were unaware of their HIV-positive status prior to HIV screening. In this study, T2 tumor was most common, and 26% cases required extended enucleation/orbital exenteration to achieve complete tumor resection.

Outcomes of Trabeculectomy With Transconjunctival Application Versus Subconjunctival Application of Mitomycin C

PURPOSE

To compare outcomes and complication rates of trabeculectomy with either transconjunctival mitomycin C (MMC) or subconjunctival MMC application.

METHODS

Retrospective cohort study-35 eyes in subconjunctival group and 29 eyes in transconjunctival group. All surgeries were performed by 1 surgeon (E.A.) at 1 center with an average follow-up duration of 40 to 51 months.

RESULTS

The mean percentage intraocular pressure reduction at final follow-up was with 44.4±25.3% reduction in the subconjunctival group compared with 48.0±24.6% reduction in the transconjunctival group, with no statistical significant difference between the 2 groups (P=0.57). Both groups also showed a >40% reduction in intraocular pressure in approximately 67% of eyes. There were no cases of endophthalmitis. There was 1 reported case of choroidal hemorrhage following subconjunctival application of MMC. There were similar low rates of postoperative bleb leakage and requirement for postoperative application of 5-fluorouracil. There was a greater incidence of hyphema in the subconjunctival group (5 vs. 1) as well as choroidal effusions (8 vs. 4). One patient underwent revision of trabeculectomy and this was in the subconjunctival group.

CONCLUSION

Transconjunctival application of MMC offers a safe and effective method of performing trabeculectomy with adjunctive MMC with lower rates of complication than subconjunctival application.

Needling augmented with topical application of mitomycin C for management of bleb failure

PURPOSE

To study the effect of topical application of mitomycin C on enhancing the efficacy of needling in the management of bleb failure.

PATIENTS AND METHODS

Thirty-six eyes of 32 consecutive patients with an intraocular pressure over 21 mmHg, without bleb or with a thick, flat bleb after the second postoperative month after trabeculectomy, were included in the study. Needling with mitomycin C was performed in the other 18 eyes with bleb failure (group A) and needling without antimetabolite was performed in 18 eyes (group B). Topical application of mitomycin C (0.4 mg/mL) with a microsponge over the conjunctiva at the failed bleb for 5 minutes (group A) was performed; after irrigation, the needling procedure was the same in both groups. A 30-gauge needle was used to perforate the area of subconjunctival and subscleral fibrosis and to reestablish flow; conjunctival puncture was at least 7 mm away from the bleb and no sutures were taken after needling. Follow-up was performed for 1 year after needling.

RESULTS

Overall, 55 needling procedures were performed; needling was done twice in 17 eyes in group B, whereas only 2 eyes needed more than 1 needling procedure in group A. The difference was statistically highly significant, and the mean follow-up was 8.9 ± 3.7 months. Mean intraocular pressure was 28.9 ± 4.2 mm Hg and 27.8 ± 4.7 mm Hg in group A and group B respectively before any intervention; this decreased to a mean of 19.8 ± 2.7 mm Hg and 20.5 ± 4.8 mm Hg respectively without medication after 6 months of last needling. Complications included diffuse corneal punctate epitheliopathy lasting for 2 to 3 weeks (2 eyes in group A), subconjunctival hemorrhage (3 eyes in each group), and hyphema (2 eyes in each group).

CONCLUSIONS

Topical application of mitomycin C with needle revision seems to be an extremely effective way to revive failed filtration surgery. The incidence of complications related to mitomycin C was minimal.

Topical Mitomycin-C versus Subconjunctival 5-Fluorouracil for Management of Bleb Failure

PURPOSE

To compare the efficacy and safety of topical mitomycin-C (MMC) drops with that of subconjunctival 5-fluorouracil (5-FU) injections for management of early bleb failure after trabeculectomy or combined phacoemulsification and trabeculectomy with posterior chamber intraocular lens implantation (PT+PCIOL).

METHODS

In a randomized comparative study, 37 eyes of 37 patients with impending early bleb failure received MMC 0.02% eye drops for 2 or 4 weeks (19 eyes) or subconjunctival 5-FU injections, 5 mg per dose (18 eyes). Complete success was defined as 5 < IOP ≤ 18 mmHg without medications.

RESULTS

Baseline characteristics were comparable between the study groups. However, there were more cases of combined PT+PCIOL in the MMC group [11 (57.9%) eyes versus 3 (16.7%) eyes, P = 0.017]. Mean preoperative IOP was 20.5±8.85 mmHg in the MMC group and 25.82±11.35 mmHg in the 5-FU group (P = 0.129), which was decreased to 13.2±6.1 and 10.6±4.8 mmHg respectively after 12 months (P = 0.159). There was no significant difference between the study groups in terms of bleb extent (P = 0.170), height (P = 0.178) or vascularity (P = 0.366). At the end of the study, complete success was achieved in 13 eyes (68.4%) in the MMC group and 14 eyes (77.8%) in the 5-FU group (P = 0.714). The survival of success at 8 months (median follow-up) was 89.5% and 86.5% in the MMC and 5-FU groups respectively; the number of glaucoma medications (P = 0.707) and best-corrected visual acuity (P = 0.550) were also comparable. Complication rates were similar in the study groups (P = 0.140).

CONCLUSION

Topical MMC 0.02% has comparable safety and efficacy to subconjunctival 5-FU injections for management of early bleb failure. Topical MMC 0.02% drops are more convenient and can be initiated first, while 5-FU injections may be reserved for eyes with an insufficient response to topical MMC.