Glaucoma management and future prospects

Pubblicato il

Monday, 23 March 2015

Argomento

Glaucoma

We put some questions to the Prof. Shlomo Melamed of Tel Aviv University to understand the state of the art and future prospects in the management of glaucomatous disease.

Due to his professional expertise, Prof. Melamed can be an excellent guide for us in discovering the latest technological and scientific developments.

We can start our interview with your opinion on the importance of technological research.
There is no doubt that research and technological development are essential for a better diagnosis and treatment of glaucoma.

Could you tell our readers about recent applications of laser use in penetrating and non-penetrating glaucoma surgery?
I am actively involved in the development and evaluation of CO laser sclerectomy.₂which is a minimally invasive procedure aimed at uncovering Schlemm's canal ab-externally. This may correspond to the definition of 'non-penetrating' surgery, although I feel that we should not use this expression, as all our procedures are 'penetrating' in some way.
In the past, numerous attempts have been made to use different types of lasers for full-thickness filter surgery. We tried the Flash-Lamp Pulsed Dye Laser to create an ab-internal sclerectomy after staining the trabecula with Methylene Blue, but the hypotensive effect was short-lived. Holmium laser and even excimer laser (by Prof. Carlo Traverso) were also used, but due to practical problems and complications related to full-thickness surgery - none of them led to a routine glaucoma treatment procedure.

Do you think that surgical expertise will remain central with the development of increasingly precise lasers?
This is a complex issue. On the one hand, increasingly sophisticated lasers and their increased precision will allow us to be more accurate when working on very small structures (such as Schlemm's canal).
On the other hand, the more advanced the tools we have at our disposal, the higher we will aim, aiming at targets that would have been unattainable with our previous skills, and this may require superior surgical expertise.

What are the main advantages and limitations of innovative techniques compared to traditional trabeculectomy?
The main advantage is the elimination of the filter draft, which is the source of so many problems such as: foreign body sensation, pain, discomfort, Dellen formation, hypotonia, filter draft infection and endophthalmitis.
Limitations may arise from the use of more complex and sophisticated technologies for new procedures that make surgery more challenging.

When is laser trabeculoplasty advisable in the management of primary glaucoma? Can it be used as a first therapeutic approach?
Selective Laser Trabeculoplasty (SLT) should be recognised as a possible option for the treatment of primary glaucoma in cases of ocular hypertension, primary open-angle glaucoma and pseudo-exfoliative glaucoma. We published the first paper on the use of SLT as primary treatment in 2004, with the 31% for IOP reduction. This 'magic number', the 30-31% of IOP reduction was also reported by Mcintyre, Nagar, and the multicentre study comparing SLT and medical therapy (Katz et al.). I routinely explain to these patients the option of SLT versus an initial approach with medical therapy, and many patients prefer SLT because of the following advantages: excellent safety profile, efficacy of 92% for 3 years, quick and easy procedure, no need for eye drops, and cost advantages (SLT was found to be 'cost effective' compared to medication after two years).

Do pigmentary and pseudo-exfoliative glaucoma require a specific approach?
In both cases, more care is needed in the delivery of laser energy due to excessive pigmentation of the angle.

Is research into the cell death mechanisms of retinal ganglion cells (RGCs) set to change our approach to the diagnosis and treatment of glaucoma?
This is a key issue in glaucoma research. Once we gain a better understanding of what triggers RGC death and how the apoptotic mechanism can be modified, we will be able to develop a neuroprotective approach that will hopefully 'save' the optic nerve from damage progression.

Do you think that glaucoma screenings are to be recommended and bring benefits that correspond to their costs?
Screening for glaucoma is anything but easy. Screening should be based not only on the measurement of IOP, but also on the collection of historical and clinical data, taking into account the optic nerve and including visual field testing. These requirements may limit the large-scale implementation of population-based screening for glaucoma.

In the current state of scientific knowledge, are there reliable biomarkers for patients at risk of glaucoma?
In the current state of the art, there is no 'acceptable' and reliable biomarker for assessing glaucoma risk that we can routinely use. I have no direct experience in this fascinating new field of research and can simply refer to our colleague, Prof. Stefano Gandolfi, who is actively involved in the study of a variety of biomarkers for glaucoma risk.

GLAUCOMA MANAGEMENT AND FUTURE PERSPECTIVES
(Original text in English)

We have asked a few questions to Prof. Shlomo Melamed of Tel Aviv University to understand the state of the art and the future perspectives in glaucoma management. For his professional expertise he can be for us an excellent guide to the latest technological and scientific developments.

We can start our interview with your opinion about the importance of technological research.
No doubt that technological research and development are essential for improved diagnosis and treatment of Glaucoma.

[caption id="attachment_1510" align="alignright" width="132"] Shlomo Melamed
Full professor of ophthalmology at Tel Aviv University Medical School and Director of the Sam Rothberg Glaucoma Center, Tel Hashomer (Israel).[/caption]

Could you explain to our readers the recent applications of the use of laser in penetrating and nonpenetrating glaucoma surgery?
I am actively involved in the development and evaluation of the CO₂ laser Sclerectomy which is a minimally invasive procedure aimed at the un-roofing of Schlemm's canal ab-externo. This may fit into your definition of "Non-Penetrating" surgery, although I don't think we should use this term, as all of our procedures are somehow "penetrating".
There were several attempts in the past to use various lasers for full-thickness filtration surgery. We tried the Flash-Lamp Pulsed Dye Laser for creating a sclerectomy Ab-Interno after staining the Trabeculum with Methylene Blue, but the hypotensive effect was short lived. Holmium Laser and even Excimer laser (by Prof. Carlo Traverso) were used as well, but due to practical issues as well as complications related to full-thickness surgery - all of them have not materialised into routine procedures for Glaucoma.

Do you think that surgical expertise will maintain a central importance with the development of more and more precise lasers?
It is a hard question. On one hand, refining lasers and improved precision of laser systems will enhance our abilities to be more accurate while focusing on miniature structures (such as Schlemm's Canal). However, the more advanced tools we shall have, we shall dare more by aiming at targets which have been out of the scope of our abilities to treat, and this may require additional surgical expertise.

Which are the main advantages and limits of innovative techniques compared with traditional trabeculectomy?
The main advantage is getting rid of the filtration bleb, which is a source for so many troubles such as: foreign body sensation, pain, discomfort, Dellen formation, hypotony, blebitis and endophthalmitis.
The limits may be the more complex and complicated technologies required for new methodologies which make the surgery more demanding.

When laser trabeculoplasty can be recommended in the management of early glaucoma or even as primary treatment?
Selective Laser Trabeculoplasty (SLT) should be recognised as an option for Primary Glaucoma treatment in cases of OHT, Primary open angle glaucoma and PXF Glaucoma. We published in 2004 the 1^st paper on use of SLT as primary Rx, with 31% reduction of IOP . This "magic number" of 30-31% IOP reduction was also reported by Mcintyre, Nagar, and the multi-center study comparing SLT to Medical Rx (Katz et al.). I routinely explain to these patients the option of SLT vs. start of Medical Rx, and many patients prefer the SLT due to these advantages: superb safety profile, 92% efficacy for 3 years, quick and easy procedure, no need for drops and cost issue (SLT was found to be cost effective over drugs after 2 years).

Pigmentary and pseudoexfoliation glaucoma require which kind of specific approach?
Both require more careful energy delivery due to excessive pigmentation in the angle.

Will the research concerning the mechanisms of retinal ganglion cell death change our approach to glaucoma diagnosis and treatment?
This is a key issue in Glaucoma research. Once we understand better what triggers RGC's death and how the apoptotic route can be modified - we shall be able to come up with a Neuroprotective approach which will hopefully 'save' the optic nerve from further damage.

Do you think that glaucoma screenings should be recommended and are worth their costs?
Screening for Glaucoma is not an easy task. Screening should be based not only on measurement of IOP, but also on collecting historical and clinical data, evaluating optic nerves and performing visual field tests. These requirements may limit large scale population screening for Glaucoma.

At the present state of scientific knowledge are there reliable bio-markers for glaucoma risk-patients?
At the current state of the art, there are no 'acceptable' and reliable bio-markers evaluating risks for Glaucoma which we can use routinely. I have no experience in this intriguing new field of research, and can only refer you to our colleague Prof. Stefano Gandolfi, who is actively involved in studying a variety of bio-markers for Glaucoma risk.

Dr. Carmelo Chines
Direttore responsabile