Tuesday, December 31, 2019


Perhaps this year is the most anticipated period in the lives of ophthalmologists. The number 2020 signifies normal vision and conjures our expectations in achieving this level in patient management.

The Glog is an effort to share glaucoma related information. And we hope this year proves to be informative, interesting, friendly and warm in our little world. This blog is the little cocoon to take one away from all of life’s troubles and just have a nice time both professionally and personally. It is a place to learn and share and just be happy. I hope we can achieve that target here.

We also have brought on board a friendly person who can help contribute new ideas to The Glog. Dr Ghuncha Khatoon has consented to help us as sub-editor now. We extend our heartiest welcome to her.

Dr Ghuncha Khatoon

The Glog wishes everyone a very happy, prosperous and peaceful 2020.


Guest author
Ajmal Khan Tibbiya College


Trabeculectomy currently remains the “gold standard” for filtration surgery.
A disadvantage of this procedure is postoperative fibrosis and scarring, leading to bleb failure and rise of intra-ocular pressure (IOP).
Concern over postoperative scarring has led to the widespread intra- and post-operative use of antifibrotic agents, particularly 5-Fluorouracil(5-FU) and Mitomycin C (MMC). These agents, however, may bring an increased risk for chronic bleb leaks, hypotony, blebitis and even endophthalmitis.
One solution to this challenge may have its roots in the burgeoning field of “tissue bioengineering”.


The biodegradable collagen matrix (BCM) implant is being marketed, depending on the country, as OlogenTM (Aeon Astron Corporation) or iGenTM (Life Spring Biotech Company), both based in Taipei, Taiwan.

It takes advantage of micro-technology and tissue bioengineering by having a molecular structure that permits the formation of a spongy filtration bleb without the use of antifibrotic agents.
The implant is a 3D porous scaffold made of 1% collagen/C-6-S copolymer with a pore size ranging from 20-200ยต.
It measures 4x7 mm and has a cylindrical shape, allowing for easy insertion and manipulation during glaucoma surgery.
The implant encourages the formation of a spongy meshwork of fibroblasts and connective tissue in a controlled and organized pattern. It forces fibroblasts and myofibroblasts to only grow into the pores, during the early postoperative period and secrete connective tissue in the form of a loose matrix.
After the polymer scaffold biodegrades, it leaves a milieu of organized fibroblasts, myofibroblasts and extra-cellular matrix. This leads to a reduced scar formation.
The implant also maintains an elevated bleb while the healing process is underway.
In trabeculectomy, early inflammation can lead to adhesion of the conjunctiva and episcleral surface during the early postoperative phase.


A conjunctival flap (limbus or fornix based) is created.
A partial thickness scleral flap is then formed.
A sharp blade is used to enter the anterior chamber at the base of the scleral flap.
A sclerostomy is created with a punch or en bloc excision, after which the scleral flap is closed with two-to-four 10-0 nylon sutures.
The BCM implant is then placed directly above the scleral flap and the conjunctiva closed as per surgeon’s preference.


Chen et al performed trabeculectomy with the BCM implant in one eye of 17 rabbits and standard trabeculectomy without anti-fibrotic agents in the fellow eye as control.
For the first 2 post-operative weeks IOP was similar in the two groups. Subsequently, the IOP decreased in the implant group as the matrix dissolved. Conversely, the IOP in the control group progressively elevated to post-operative levels.
Another study was performed in 30 rabbits undergoing trabeculectomy with the implant were compared with a control group of rabbits undergoing trabeculectomy without it.
In both groups, the conjunctiva was incompletely sutured to produce a wound leak. Although the conjunctival defect sealed equally well in both groups, IOP was significantly lower in the implant group after conjunctival healing was complete.

The BCM implant is now available in Europe and Asia.
Chen and Hsu reported the preliminary results of the experience in 12 patients. They found a 64% reduction in IOP four months after surgery. The average number of glaucoma medications also decreased from 2 to 0.3.
Ruokonen et al. reported their experience in 17 patients with open angle glaucoma. IOP improved from 30 to 14 mmHg within 3 months after surgery. The average number of glaucoma medications required decreased from 3.3 to 0.2. Eleven eyes developed bleb encapsulation with elevated IOP after 7 months. Of these some responded well to needling and 2 required further surgery to control IOP.
Another study reported the outcomes of 20 consecutive patients who underwent trabeculectomy with implant placement. After 3 months, mean IOP decreased from 33.8 to 13.3 mmHg. All patients tolerated the implant well and no systemic adverse-effects were noted.
Researchers in China studied the effects of trabeculectomy with the implant versus trabeculectomy without anti-fibrotics. The mean IOP was significantly lower in the implant group after 6 months of follow-up. The risk of bleb failure was 30% lower in the implant group.
The BCM implant is also being used in cases of combined cataract extraction and trabeculectomy. Grewel et al. studied 10 patients with POAG who were undergoing combined phacoemulsification with trabeculectomy and implant placement. At 3 months post-operatively, mean IOP had improved from 20 to 9 mmHg and the mean number of topical glaucoma medications needed reduced from 2.7 to 0.9.


The BCM implant invokes the concepts of tissue bioengineering to promote successful glaucoma filtration surgery. The implant is largely safe, easy to handle and effective in reducing IOP without any side-effects as seen with anti-fibrotic agents.

  ologen® Collagen Matrix prevents subconjunctival, scleral and trabdoor scarring via three principal mechanisms:

  1. The volume of ologen® Collagen Matrix creates a functional bleb which maintains a physiological barrier in the subconjunctival space that prevents subconjunctival scar formation.
  2. The porous structure of the collagen matrix induces random growth of the fibroblasts into the porous structure to prevent scar formation and to modulate the wound healing process.
  3. ologen® Collagen Matrix has a superior water-absorbing abilityand an excellent pliable strength. When ologen® Collagen Matrix absorbs aqueous humor, it works like a reservoir and creates a tamponading effect on the scleral flap, which along with the use of a loose suture on the scleral flap maintains a dynamic controlled drainage of the aqueous humor outflow. These properties further prevent scar formation in the trabdoor and intra-scleral space and reduce the chances of hypotony which may be seen in trabeculectomy with the applications of anti-metabolites adjuncts before ologen® Collagen Matrix can be applied.

Thursday, December 26, 2019


Ahmad's Modified Trabeculectomy Technique (AMTT) aims to utilize subtle modifications to the classical trabeculectomy technique in order to achieve a better filtering bleb, leading to lesser complications.

Details of the AMTT study have been published in the:
Asian Journal of Ophthalmology. 2019;16:231-241.

Link ⇒

Monday, December 16, 2019



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  1. “Branch retinal artery occlusion associated with protein C and S deficiency”, poster presentation at the 25th Malaysia Singapore Joint Ophthalmic Congress, Kuala Lumpur, Malaysia, 20-22nd November, 2009:
  2. “Devastating ocular effect of rice bug- Posisang”, poster presentation at the 25th Malaysia Singapore Joint Ophthalmic Congress, Kuala Lumpur, Malaysia, 20-22nd November, 2009:
  3. “Sabah Mission For Vision: An experience in eye-care delivery in Malaysia” poster presentation at the International Forum on Quality and Safety in Healthcare, Nice, France, 20-23 April 2010.
  4. “Acanthamoeba keratitis: A challenge in diagnosis and treatment”, poster presentation at the 8th UKM Ophthalmology Symposium, Kuala Lumpur, Malaysia, 10-11th July, 2010.
  5.  “Challenges in diagnosis of choroidal melanocytoma”, poster presentation at the 27th Malaysia-Singapore Joint Ophthalmic Congress, Penang, Malaysia, 24-26th June, 2011.
  6.  “Cut-it-out technique in a case of fish hook injury”, poster presentation at the 3rd Annual Scientific meeting of the Malaysian Society of Ophthalmology, Selangor, 24-25th March, 2012.
  7. “Bilateral pigment dispersion glaucoma: A case report”, poster presentation at the 27th Asia Pacific Academy of Ophthalmology (APAO), Busan, Korea, 13-16th April, 2012.
  8.  “Ahmad’s Modified Trabeculectomy Technique”, poster presentation at the World Glaucoma Congress, Hong Kong, 6-9 June, 2015. 
  9.  “Validation of the WINROP screening algorithm among pre-term infants in East Malaysia”, poster presentation at the Asia Pacific Vitreo-retina Society (APVRS), Kuala Lumpur, 8-10 December 2017 (Best Poster Winner). 
  10.  “A boat not to miss”, poster presentation at the 8Th Conjoint Scientific Conference, Kuala Lumpur, Malaysia, 14-16th August, 2018.

Friday, December 6, 2019


Guest author
Ajmal Khan Tibbiya College 


Selective laser trabeculoplasty (SLT) is an effective treatment option for reduction of intra-ocular pressure (IOP) in patients with ocular hypertension.
SLT is at least as effective as Argon Laser Trabeculoplasty at lowering IOP in many forms of Glaucoma. SLT decreases IOP fluctuation and can be successfully used as a primary or adjunctive therapy for management of both early and advanced Glaucoma. Limited evidence suggests that SLT is cost effective as primary therapy for patients with Glaucoma.

[FURTHER READING: https://ourgsc.blogspot.com/search?q=selective]


SLT is based on the principle of selective laser thermolysis.
According to this concept, radiation energy applied to trabecular meshwork (TM) selectively targets pigmented cells without causing significant collateral thermal damage.
The SLT base is a 532-nm frequency-doubled Q-switched Nd:YAG laser with a fixed spot size of 400-nm and duration of 3 nanoseconds.
The power range for treatment varies from 0.4-1.4 mJ.
These parameters spare surrounding non-pigmented cells as the pulse duration is significantly shorter than thermal relaxation time (1 microsecond) of melanin granules contained in pigmented TM cells.


The exact mechanism by which IOP is lowered by SLT is unknown and probably multifactorial.
SLT appears to lower IOP by increasing trabecular outflow.
Proposed mechanism of action include: structural alteration inflammatory response with remodeling of extracellular matrix and stimulation of TM cell proliferative changes.


SLT is useful in various types of glaucoma including:
Normal tension glaucoma
Pseudoexfoliative glaucoma
Pigmentary glaucoma
Steroid induced glaucoma

Normal tension glaucoma:
SLT can have a significant IOP lowering effect in patients with NTG, albiet with a smaller absolute reduction in IOP. The use of SLT in NTG has been limited historically because of the fact that the most reliable predictor of success is a higher preoperative IOP. Lee et. al. treated 45 NTG eyes with 360-degree SLT after 1 month of medication washout, the IOP was significantly reduced.

Steroid induced glaucoma:
Although there is limited data available, SLT appears to effectively lower IOP in patients with steroid induced glaucoma and may even help prevent IOP spikes from subsequent steroid treatment.
SLT was found to produce a 35.9% drop in IOP over 12 months of follow up in patients with steroid induced glaucoma.


SLT is an effective treatment option for the reduction of IOP in patients with ocular hypertension and open angle glaucoma. Based on published data SLT is at least as effective as ALT and medications.

There is evidence that SLT can successfully be repeated to achieve additional or recurrent IOP reduction in eyes that had a modest response to initial treatment.

Adverse effects are uncommon after SLT. The most common complications being mild and transient rise in IOP immediately following the procedure.

SLT can be a useful and effective treatment option when medications are ineffective or are causing unwarranted side-effects.