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 Table of Contents    
ORIGINAL ARTICLE
Year : 2017  |  Volume : 10  |  Issue : 3  |  Page : 184-192  

Comparison between Ologen implant and different concentrations of Mitomycin C as an adjuvant to trabeculectomy surgery


Department of Ophthalmology, Assiut University Hospitals, Assiut, Egypt

Date of Web Publication5-Oct-2017

Correspondence Address:
Zeiad H Eldaly
Department of Ophthalmology, Assiut University Hospitals, 6th Floor, Assiut 71516
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ojo.OJO_199_2016

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   Abstract 

CONTEXT: Trabeculectomy is the most common surgical procedure for treatment of glaucoma. To improve success rates, adjuvants were utilized as Mitomycin C (MMC) and Ologen implant.
AIMS: This study aims to establish efficacy and safety of Ologen implant versus MMC in trabeculectomy.
SETTING AND DESIGN: A prospective, comparative clinical study was conducted at the Department of Ophthalmology, Assiut University, between December 2014 and April 2016.
SUBJECTS AND METHODS: Patients with primary open-angle glaucoma (OAG), primary narrow-angle glaucoma and secondary OAG were assigned equally to trabeculectomy with Ologen, 0.4 mg/mL or 0.2 mg/mL MMC. The study outcome measures were reduction in intra-ocular pressure (IOP), success rates, survival analysis, and rate of complications.
STATISTICAL ANALYSIS USED: SPSS software Version 17.0 (SPSS, Inc., IL, USA) was utilized.
RESULTS: Thirty eyes were included in the study. Mean baseline IOP in Ologen, MMC 0.4 and MMC 0.2 groups were 27.43 ± 2.97, 28.4 ± 3.24, and 27.56 ± 2.69 mmHg, respectively. At week 24 follow-up, mean IOP in Ologen, MMC 0.4 and MMC 0.2 groups were 18.55 ± 3.18, 16.2 ± 3.22, and 16.93 ± 3.04 mmHg, respectively. No significant inter-group difference was noticed at any visits. Complete success was achieved in 10%, 40%, and 30%, whereas incomplete success in 70%, 50%, and 60%, respectively in Ologen, MMC 0.4 and MMC 0.2 groups. No treatment group difference was reported by Kaplan–Meier analysis. Shallow anterior chamber occurred more in Ologen and MMC 0.4 groups. A single case of serous choroidal effusion had occurred in MMC 0.4 group.
CONCLUSION: Ologen implant is a promising alternative to MMC for improving the success rate of trabeculectomy.

Keywords: Antimetabolite, filtering surgery, intraocular pressure


How to cite this article:
Eldaly ZH, Maasoud AA, Saad MS, Mohamed AA. Comparison between Ologen implant and different concentrations of Mitomycin C as an adjuvant to trabeculectomy surgery. Oman J Ophthalmol 2017;10:184-92

How to cite this URL:
Eldaly ZH, Maasoud AA, Saad MS, Mohamed AA. Comparison between Ologen implant and different concentrations of Mitomycin C as an adjuvant to trabeculectomy surgery. Oman J Ophthalmol [serial online] 2017 [cited 2019 Oct 17];10:184-92. Available from: http://www.ojoonline.org/text.asp?2017/10/3/184/215999


   Introduction Top


Since it was introduced in 1968 by Cairns, trabeculectomy has remained the most common surgical procedure for treatment of glaucoma. The modern trabeculectomy is a safe and effective procedure, with a high success rate. The chief aim is to allow aqueous to bypass the trabecular meshwork into the sub-conjunctival space, but at the same time, ensuring an optimum intraocular pressure (IOP) as well as maintaining the anatomy of the anterior chamber (AC).[1],[2]

However, the success rate of trabeculectomy is reduced in patients younger than 40 years, black race, chronic use of topical medications as beta-blockers or pilocarpine and chronic conjunctival inflammation. To raise the success rate in high-risk group, adjuvants to trabeculectomy as antimetabolites, amniotic membrane transplantation, and expanded polytetrafluoroethylene (Gore-Tex) implants, have been tried to enhance and maintain the hypotensive effect of trabeculectomy.[3],[4],[5],[6]

Mitomycin C (MMC) is an antimetabolite that induces DNA damage by alkylation and possibly crosslinking. Free radicals are also generated that can damage many nonspecific aspects of cell function including DNA, RNA, and protein synthesis. Unfortunately, antimetabolite-augmented glaucoma surgery can be associated with a higher frequency of prolonged wound leaks, hypotony with choroidal effusions and maculopathy, thin avascular blebs, and/or bleb leaks with late infection.[7],[8]

Recently, a new biodegradable porous collagen-glycosaminoglycan (GAG) copolymer matrix implant has been proposed for glaucoma surgery. Ologen collagen matrix (Aeon Astron Europe BV, Leiden, The Netherlands) is a biodegradable implant, available in various shapes and dimensions that may maintain the hypotensive effect in glaucoma surgery.[9],[10] Its porous structure should force conjunctival fibroblasts and myofibroblasts to grow into the pores and impair connective tissue lay down reducing scar formation and wound contraction. After the implantation, the device should completely degrade within 90–180 days.[11]

The objective of this study was to compare the safety and efficacy of trabeculectomy augmented with either Ologen implant or intraoperative different concentrations of MMC (0.02 and 0.04 mg/ml). We will investigate the hypothesis that Ologen implant may be a safer alternative to the use of antimetabolites as an adjuvant in trabeculectomy surgery.


   Subjects and Methods Top


Setting and venue

This was a prospective, interventional, open-label, comparative clinical study conducted at the Department of Ophthalmology, Assiut University, between December 2014 and April 2016. The patients were enrolled after the approval of the Ethical Committee of Faculty of Medicine, Assiut University and all the study procedures were under the tenets of the Declaration of Helsinki.[12] The risks, benefits, and alternatives of the surgery were discussed with the patient, and informed consent was signed. Study design, conduct, and data collection agreed with the Guidelines on Design and Reporting of Glaucoma Surgical Trials.[13]

Inclusion and exclusion criteria

The study subjects included patients older than 18 years of age with primary or secondary open-angle glaucoma (OAG) (including pseudoexfoliation glaucoma [PXG], pigment dispersion glaucoma [PDG]) and primary narrow-angle glaucoma (PNAG). Primary OAG (POAG) was diagnosed on the basis of IOP measurements more than 21 mmHg, open angle on gonioscopy (Grade 3 or 4 on Schaffer grading system for angle width), glaucomatous visual field defects consistent with glaucomatous optic disc changes. PNAG was diagnosed by the presence of narrow or occludable angle on gonioscopy (Grade 2, or 1 on Schaffer grading system for angle width in at least 180° of the total circumference of the angle in primary position without indentation), glaucomatous optic disc changes, visual field defects and IOP more than 21 mmHg. Exclusion criteria were pregnant or lactating female, previous intraocular surgery, one-eyed patients, previous ocular trauma, uveitis-induced glaucoma, neovascular glaucoma, aphakic/pseudophakic glaucoma, systemic connective tissue disease and missing more than 3 follow-up visits. Trabeculectomy augmented by either MMC or Ologen implant was indicated to study subjects if they had uncontrolled IOP under maximum antiglaucoma medications (3 antiglaucoma drugs) or due to poor socioeconomic status.

Patient evaluation

Preoperative assessment

Preoperative baseline data were obtained 1 day before surgery and included ocular and medical history (including the use of topical antiglaucoma medications and their number, presence of systemic diseases, for example, diabetes mellitus and systemic hypertension), best-corrected visual acuity (BCVA) assessment (Landolt C chart), Manifest refraction (Huvitz auto-refractor-keratometer), Anterior segment assessment (Haag-Streit Slit lamp), IOP measurement (ICare rebound tonometer and Goldmann applanation tonometer, measurements were carried out at the same time of the day [from 10 am to 2 pm] to eliminate the effect of diurnal variation), gonioscopy (Goldmann 3-mirror contact lens), fundus Biomicroscopy to assess retina and optic disc parameters (e.g., vertical C/D ratio) (+90 D Volk non-contact lens) and visual field assessment (Octopus automated perimetry).

After recruitment of the patients, they were allocated into one of three treatment groups; trabeculectomy augmented by Ologen implant, trabeculectomy augmented by MMC (0.4 mg/ml) or trabeculectomy augmented by MMC (0.2 mg/ml).

Preparation of Mitomycin C with different dilutions

Mitomycin-C Kyowa® (Biochem Pharmaceutical Industries, India) 10 mg vial was used. It was reconstituted by 10 ml normal saline and then 2 ml was withdrawn to get a concentration of 2 mg/ml. The 2 mg/ml concentration solution was then re-diluted by 10 ml normal saline to get the concentration of 0.2 mg/ml or by 5 ml normal saline to get the concentration of 0.4 mg/ml.

Ologen Collagen Implant

Ologen Collagen Implant (Aeon Astron Europe, Netherlands) is a three-dimensional collagen- GAG implant specifically designed to promote wound healing with minimal scarring. Ologen should completely be degraded within 90–180 days after its implantation. When inserted under the conjunctiva at the time of trabeculectomy, it not only acts as a reservoir but also helps to separate mechanically the conjunctiva and episcleral surface and prevent adhesions between them.[14] Ologen consists of >90% lyophilized porcine atelocollagen and <10% lyophilized porcine GAG. Atelocollagen is a highly purified pepsin-treated type I collagen. Currently, two types of Ologen are used in glaucoma surgery, 12 mm in diameter with 1 mm of thickness and 6 mm in diameter with 2 mm of thickness.[15],[16]

Surgical procedure

Under peri-bulbar (2 cc of bupivacaine 0.5% +2 cc of xylocaine 2% +1 cc of hyaluronidase 1500 IU/ml) or general anesthesia, a partial thickness corneal traction suture was applied 2 mm from the limbus using 5/0 vicryl suture. A fornix-based conjunctival flap at the superior limbus was dissected along with the underlying tenon's capsule exposing the sclera. A trial to control bleeding was first attempted by micro-sponge application, and if failed, gentle electrocautery was applied. Delineation of a 4 mm × 4 mm rectangular superficial scleral flap was achieved by #15 surgical scalpel blade. Partial thickness superficial scleral flap was created by using a curved crescent knife to about 2/3 scleral thickness till reaching clear cornea. In the MMC Group, MMC soaked sponges (with concentration of 0.4 mg/ml or 0.2 mg/ml) were placed in the sub-conjunctival space over a wide area up to the fornices and beneath the superficial scleral flap for 3 min ( first sponge was used to sweep the sub-conjunctival space and deep scleral bed, then 3–4 sponges were embedded in the subconjunctival space). The sponges were then removed, and the area exposed to MMC was copiously irrigated with 30–50 cc of saline. Fashioning of corneoscleral tissue block measuring 1 mm × 2 mm was performed using a microvitreoretinal blade (MVR blade) preceded by a paracentesis. By using Vanna's scissors, the internal tissue block was removed and wide basal peripheral iridectomy was done. The superficial scleral flap was closed with two 10/0 Nylon suture at the angles. In Ologen group, a 6 mm × 2 mm Ologen implant was placed on top of the sclera and the conjunctiva (overlying the superficial scleral flap), and then the conjunctiva was secured with two 8/0 Vicryl wing sutures. A 10/0 Nylon transverse mattress suture was done to avoid an aqueous leak. Wound sealing test was done by intra-ocular irrigation of saline through the paracentesis to check for wound leak and bleb formation. Stromal hydration was done for the closure of paracentesis.

Postoperative medications

Postoperatively, all patients were treated with prednisolone acetate 1% eye drops 5 times daily for 4 weeks followed by gradual tapering according to physician judgment, gatifloxacin eye drops 5 times daily for 2 weeks, and cyclopentolate 1% eye drops 3 times daily for 2 weeks.

Follow-up visits

Postoperative visits were scheduled at day 1, week 1, week 2, week 4, week 12, and week 24. At each visit, IOP and complications were recorded. In the 1st postoperative day, IOP was measured by IC are rebound tonometer using new prong for every patient to eliminate the risk of infection. Afterward, Goldmann Applanation tonometer was used. If any complication develop at any time during follow-up, frequent visits were advised, and medications were prescribed according to physician discern.

Definition of success and failure

Surgery was considered as a complete success when IOP was equal or <15 mmHg and >6 mmHg with or without antiglaucoma medications at week 24 postoperative follow-up visit and an incomplete success when ≤21 mmHg and >15 mmHg with or without medications at week 24 postoperative follow-up visit. It will be a failure when IOP was >21 mmHg with or without medication or when an eye requires further glaucoma surgery or lost light perception.

Data collection

Clinical information including preoperative clinical findings, surgical procedure, postoperative results, complications and subsequent follow-up visits, were entered into the database. A format was devised using Microsoft Excel (Microsoft Corp, Washington, USA) to collect clinical information from the patients' records.

Statistical analysis

The statistical analysis was performed by SPSS software V. 17.0 (SPSS, Inc., IL, USA). The value of P < 0.05 was considered statistically significant.


   Results Top


Study participants

Between December 2014 and April 2016, 41 patients had participated in the study. Six cases were excluded before assignment to either treatment groups; 2 cases of neovascular glaucoma, 2 cases of pseudophakic glaucoma, 1 case of inflammatory glaucoma and 1 case of previously failed trabeculectomy. Five patients were excluded after assignment to treatment groups due to missing >3 follow-up visits. Thirty patients fulfilled inclusion criteria and completed 24 weeks of follow-up.

Baseline patients' characteristics

Thirty eyes (30 patients) fulfilled inclusion criteria and assigned to one of 3 study groups. Each study group included 10 eyes (10 patients). Participants were 17 male and 13 female. Baseline patients' characteristics are summarized in [Table 1] with no significant difference between treatment groups regarding the mean age of the patients (P > 0.05).
Table 1: Demographic characteristics of patients

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Baseline examination

Baseline evaluation is summarized in [Table 2]. Mean baseline BCVA in Ologen, MMC 0.4 mg/ml and MMC 0.2 mg/ml treatment groups was 0.15 ± 0.07, 0.15 ± 0.08 and 0.16 ± 0.09 respectively with no significant difference among treatment groups. Mean baseline IOP measurements in Ologen, MMC 0.4 mg/ml and MMC 0.2 mg/ml treatment groups were 27.43 ± 2.97, 28.4 ± 3.24 and 27.56 ± 2.69 mmHg, respectively, with no significant difference among treatment groups.
Table 2: Baseline patient assessment

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Effect of treatment on intra-ocular pressure

One day postoperatively, the IOP dropped to 12.37 ± 2.99, 10.2 ± 3.72 and 11. 1 ± 3.52 mmHg respectively in Ologen, MMC 0.4 mg/ml and MMC 0.2 mg/ml treatment groups with mean reduction of 15.03 ± 2.65 mmHg (95% confidence interval [CI]; 13.17–16.96) in Ologen group, 18.2 ± 3.93 mmHg (95% CI; 15.39–21.01) in MMC 0.4 mg/ml group and 16.4 ± 2.73 mmHg (95% CI; 14.52–18.42) in MMC 0.2 mg/ml group. No inter-group significant difference was noticed at any scheduled postoperative follow-up visit (independent sample t-test). The postoperative IOP reduction was still significant at week 24 in all treatment groups (Baseline-week 24 Paired sample t-test; P < 0.001 in all treatment groups), with a mean IOP reduction from baseline of 8.88 ± 2.29, 12.2 ± 1.81 and 10.64 ± 1.88 mmHg in Ologen, MMC 0.4 mg/ml and MMC 0.2 mg/ml treatment groups, respectively. No significant difference in IOP values from day to week 24 among all treatment groups (one-way analysis of variance) [Figure 1].
Figure 1: Mean intraocular pressure change at follow-up visits in the study

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There was a statistically significant difference in mean IOP reduction from baseline between Ologen and MMC 0.4 mg/ml treatment groups (−3.32 ± 2.99 [95% CI; −5.46–−1.19, P = 0.007]). There was no statistically significant difference in mean IOP reduction from baseline between Ologen and MMC 0.2 mg/ml treatment groups (−1.76 ± 2.96 [95% CI; −3.87–0.35, P = 0.93]) or between MMC 0.4 mg/ml and MMC 0.2 mg/ml treatment groups (1.56 ± 2.86 [95% CI; −0.47–3.6, P = 0.117]).

Success rates

The success rates in the study groups are reported in [Figure 2]. The proportion of success at IOP ≤21 mmHg (including complete and incomplete success) was 80% in Ologen treatment group and 90% in both MMC treatment groups. All failed cases (4 eyes) were attributed to an inability to achieve postoperative IOP ≤21 mmHg. Patients who failed to fulfill success criteria were equal between male and female (2 males and 2 females). Patients who fulfilled complete success criteria were also equal between male and female (4 males and 4 females).
Figure 2: Success rates (number of cases) at week 24 follow-up end point in the treatment groups at two target intraocular pressure levels

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Patients who failed to fulfill success criteria were 2 patients in PNAG group (2/15 patients), 1 patient in POAG group (1/12 patients) and 1 patient in PXG group (1/2 patients). Patients who fulfilled complete success criteria were 4 patients in PNAG group (4/15 patients), 4 patient in POAG group (4/12 patients) and none of the patients in PXG/PDG group (0/3 patients).

Survival analysis

The Kaplan–Meier survival curves related to 15 mmHg target IOP did not show any significant inter-group differences for complete success (log-rank, P = 0.072, Breslow, P = 0.325, and Tarone-Ware, P = 0.169) [Figure 3].
Figure 3: Kaplan–Meier cumulative probability curve of complete success at 15 mmHg target intraocular pressure in all treatment groups

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Complications

The surgical complications encountered in each group are listed in [Table 3]. No anesthesia-related complications were encountered in any treatment group. No Ologen implant extrusion or conjunctival erosion was noted in Ologen group. The frequency of postoperative complication did not significantly differ between treatment groups.
Table 3: Intra- and post-operative complications in Ologen and Mitomycin-C groups

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However, shallow AC (with negative Seidel test) was more frequent in Ologen and MMC 0.4 mg/ml groups than MMC 0.2 mg/ml (4, 4 and 3 eyes, respectively), while hypotony was more frequent in MMC 0.4 and 0.2 mg/ml groups (3 and 2 eyes, respectively) than in Ologen group (1 eye). A single case of serous choroidal effusion had occurred in MMC 0.4 mg/ml. This was a 59-year-old diabetic female with PNAG. Her baseline IOP was 26.33 mmHg. She underwent uneventful trabeculectomy surgery augmented by MMC 0.4 mg/ml. In the 1st postoperative day, she was presented with shallow AC (no kerato-lenticular touch, negative Seidel test), hypotony and patent peripheral iridectomy. US revealed peripheral serous choroidal effusion at day 3 postoperatively [Figure 4]. Frequent steroids, serial US, and closer follow-up were advised. At 2-week follow-up visit, IOP was 9 mmHg with the restoration of AC depth. At week 4, IOP was 14 mmHg with AC depth comparable to the other contralateral eye. Endophthalmitis did not occur in any of treatment groups.
Figure 4: Ultrasonography of the right eye revealed serous choroidal effusion (top). Two weeks later, follow-up US revealed resolution of choroidal effusion (bottom)

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   Discussion Top


Trabeculectomy has been used for more than 40 years and still is the most common incisional surgery for glaucoma.[17] Trabeculectomy as the standard procedure in filtering glaucoma surgery was introduced by Cairns in 1968.[1]

Postoperative scarring is a major problem that affects the long-term success of trabeculectomy. Since the 1980s, antimetabolite agents such as MMC, which reduce fibroblast proliferation in the subconjunctival space and in Tenon's capsule and thereby inhibit scar formation, have been widely used to augment the success rates of trabeculectomy.[18] However, because of the toxicity associated with such agents; there is a greater risk of complications, such as corneal endothelial cell loss,[19] cystic thin avascular bleb, choroidal detachment,[20] and endophthalmitis.[21] Implantation of Ologen in the subconjunctival space offers a new opportunity to prevent the fore-mentioned complications associated with MMC-augmented filtering surgery and to avoid early scar formation. Ologen is composed of a porous matrix of cross-linked atelocollagen and GAG. It contains thousands of microscopic pores and can induce fibroblast growth, leading to a well-organized and healthy healing process.

The ideal adjuvant to trabeculectomy surgery would interfere with healing process and subconjunctival fibrosis to maximize IOP reduction and success rates. Meanwhile, it should pose the least toxic effect and should have a good safety profile.

In the current study, all groups demonstrated a significant reduction in the mean IOP at week 24 follow-up. Both adjuvants (Ologen implant and MMC in different concentrations) were efficient in lowering IOP significantly from the preoperative level, as evidenced by a significantly lower IOP at all the follow-up visits in all groups. There was no statistically significant difference in the mean IOP among all groups at any follow-up visits. We found the success rate of trabeculectomy at week 24 was similar in MMC groups and higher than Ologen group (90% and 80% in the MMC and Ologen groups, respectively) [Figure 5].
Figure 5: Slit-lamp photography of trabeculectomy 1 and and 6 months post-operatively. Top: Ologen, middle: MMC 0.2 mg/ml & bottom: MMC 0.4 mg/mlgroup

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Papaconstantinou et al. had compared trabeculectomy with and without Ologen implant. With a 6 months follow-up, they reported a similar success rate of 90% in both the groups, similar to what we have reported.[22] Rosentreter et al. compared 10 eyes each in trabeculectomy with MMC and Ologen groups and reported significantly higher success rate at the end of 12 months in trabeculectomy with MMC group (100% with MMC vs. 50% with Ologen). However, Rosentreter et al. had evaluated a single concentration of MMC (0.2 mg/ml), whereas we evaluated 2 different concentrations of MMC (0.4 and 0.2 mg/ml).[14] Boey et al., in their study comparing phaco-trabeculectomy with MMC and Ologen implant, reported significantly greater IOP control in MMC group at 3 months follow-up.[23]

In the study conducted by Senthil et al., the difference in the complete and qualified success rates (complete success is defined as achieving an IOP of ≤18 mm Hg at week 24 follow-up while qualified success is defined as achieving an IOP of ≤15 mm Hg at week 24 follow-up) was not statistically significantly different between the groups.[24]

On the contrary, Yuan et al. had documented a significantly higher complete success proportion (Complete success was defined as an IOP ≦21 mmHg, with no additional glaucoma medications whereas relative success was defined as an IOP ≦21 mmHg but with additional glaucoma medications) among Ologen group than MMC 0.2 mg/ml group (61% and 31%, respectively) while nonsignificant difference in relative success proportion in Ologen and MMC groups (19% and 28% respectively). Furthermore, overall success was significantly higher in Ologen group than MMC group (84% vs. 59%).[25]

Final IOP measurements were variable among different studies. Yuan et al. reported that mean IOP at 5-year follow-up was 15.11 ± 3.55 mmHg in Ologen group and 19.98 ± 4.18 mmHg in MMC group.[25] The pressure level in the MMC group was about 4 mmHg lower than that in the Ologen group as reported by Rosentreter et al. (15.6 ± 2.4 mmHg in Ologen group vs. 11.3 ± 3.9 mmHg in MMC Group).[14] Cillino et al. had found a small difference between MMC and Ologen groups after 60-month follow-up (15.2 ± 3.2 mmHg and 15.8 ± 2.3 mmHg, respectively).[26] Although the current study follow-up period was 24 weeks (about 6 months), final IOP outcome was comparable to long-term follow-up studies. However, Senthil et al. have found a lower IOP in the Ologen group than the MMC group (11.6 ± 2.7 mmHg and 14.3 ± 6.4 mmHg, respectively).[24] Narayanaswamy et al. had found no statistically significant difference between Ologen and MMC 0.4 mg/ml (15.5 ± 2.9 and 14.2 ± 4.6 mmHg, respectively).[27]

In the study by Rosentreter et al., 2 cases (20%) in Ologen group developed shallow AC whereas MMC group developed shallow AC in a single case (10%). They reported about early hypotony in 60% of cases in Ologen group as compared to 30% in MMC 0.2 mg/ml. This could be attributed to their surgical protocol of loose single suturing of the scleral flap. They also reported a single case of suprachoroidal effusion. We reported shallow AC more common than Rosentreter et al. In contrary of the current study, they reported more frequent cases of early hypotony in all treatment groups. No cases of Tenon cyst was reported in contrast to 2 cases in the study conducted by Rosentreter et al. We could explain such finding by the 24-week follow-up duration, while Tenon cyst takes more time to develop in most of cases. Also, no cases of bleb leak were found in the study. On the other hand, Rosentreter et al. reported 3 cases of bleb leak on Ologen group and 2 cases in MMC group. This could be explained by watertight closure of conjunctiva along with transverse mattress suture at the limbus securing the conjunctival sealing.[14]

Cillino et al. reported higher rates of early hypotony in both MMC 0.2 mg/ml and Ologen groups (40% and 20%, respectively) than found in the current study. Also, they reported higher rates of suprachoroidal effusion in MMC 0.2 mg/ml and Ologen groups (25% and 10%, respectively) than current study, although the single case of suprachoroidal effusion was with a higher concentration of MMC (0.4 mg/ml).[26]

Senthil et al. had reported similar rates of postoperative complications regarding shallow AC and hypotony. However, they presented a higher rate of early hyphema in Ologen group and attributed it to loose scleral flap suturing (as recommended by the manufacturer) that allowed the ooze from the cut-ends of the sclera to enter into the AC. Also, a higher but similar rate of suprachoroidal effusion had been documented (21% in Ologen group and 15% in MMC 0.4 mg/ml).[24]


   Conclusion Top


We conclude that the Ologen implant may be a safe and effective alternative to MMC for improving the long-term success rate of trabeculectomy surgery and may avoid the side effects associated with the use of adjunctive therapy, such as MMC. Limits related to the small sample size must be overcome by further larger sample size and randomized trials to confirm the efficacy and safety of this implant. However, MMC-augmented trabeculectomy yielded a lower IOP reduction, but the Ologen augmented trabeculectomy provided a safe adjuvant in terms of surgical complications. To the best of our knowledge, this is the first interventional study to compare the safety and efficacy of Ologen collagen implant with different concentrations of MMC (both high concentration of 0.4 mg/ml and low concentration of 0.2 mg/ml).

Acknowledgment

None to declare.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
   References Top

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    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

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