SLT and MLT offer a safe & effective alternative to long term eye drops
Laser Trabeculoplasty (SLT & MLT) are treatment options for Glaucoma or Ocular Hypertension where gentle laser energy (light waves) are applied to the trabecular meshwork (the “drain” or “plug hole” within the eye).
The laser energy has no visible effect – it does not burn, scar or cause contraction. Instead it modulates the function of trabecular meshwork to encourage increased drainage of fluid from the eye and hence reduce intraocular pressure.
LASER means “light amplification by stimulated emission of radiation”
It is just highly specific and precisely controlled light
Laser Trabeculoplasty: does it work ?
Laser Trabeculoplasty (LT) may be useful in the treatment of both Ocular Hypertension (OHT) and Glaucoma (including many subtypes). For a full and honest discussion about whether LT is correct for you it is always recommended that a face-to-face meeting is arranged (see here for Mr Lindfield’s practice locations).
There are four areas where LT can be of benefit:
1) As an alternative to eye drops for OHT & Glaucoma – LT may allow existing eye drops to be stopped or can be first line therapy (use laser instead of drops from the onset)
2) To reduce the number of eye drops you require – The pressure lowering effect of LT can allow eye drops to be reduced whilst still controlling intraocular pressure and preventing progression of your disease. Often this is a reduction of one drop but reductions of 2-3 are possible.
3) To save adding further eye drops to your existing regime – If your OHT / Glaucoma is sub optimally controlled than often further eye drops are required. LT may allow eye pressure reduction to within target levels without needing further medication and their possible side effects
4) Prevent or delay the need for surgery. LT may produce sufficient eye pressure reduction without needing to progress to surgery with its associated risks and inconvenience.
If you currently take 1 medication to control your eye pressure then LT should allow an 80% chance of stopping this drop
If you currently take 2 medications then LT should allow drop freedom in 40-60% of people
However. LT does not have a permanent effect. It wears off over time (see below)
SLT Laser Video:
This explanatory video from Ellex nicely describes who can benefit from SLT and how it works
Mr Lindfield’s view whilst performing LT: A contact lens is placed on the eye to allow the trabecular meshwork to be visualised. The red dot is the aiming beam for the laser. You can see the tiny “champagne bubbles” formed as the laser is fired and the light energy treats the trabecular meshwork
The average survival time of the treatment is around 2 years
“SLT” and “MLT” : what is the difference?
Laser trabeculoplasty has three subtypes:
ALT Argon Laser Trabeculoplasty. This is now considered old technology mostly attributable to the higher incidence of side effects compared to newer modality. It physically damages the trabecular meshwork (“plug hole cells”) and is not repeatable.
SLT Selective Laser Trabeculoplasty. The most commonly performed modality world wide. It does not cause any visible damage to the trabecular meshwork but “gently tickles” the cells encouraging them to allow more aqueous fluid to drain, hence reducing pressure.
MLT Micropulsed Diode Laser Trabeculoplasty. The same risk, effectiveness and repeatability profile as SLT but uses a different laser wavelength. MLT uses a laser which switches on and off many times per “shot” and hence proclaims to cause less inflammation and improve safety. The benefit is yet to be research proven but results are very similar to SLT.
click here for a more detailed comparison of ALT, SLT & MLT
Patient Information Sheet for Laser Trabeculoplasty available here
SLT provides a clinically significant reduction of pressure. In a recent review of the published evidence (full text here) the average intraocular pressure reduction was:
– at 6 months average reduction 21.8 – 29.4%
– at 12 months average reduction 16.9 – 30.0%
– at 3 years average reduction 24.5 – 25.1%
– A reduction in pressure of 20% (or greater) at 12 months was achieved in 58-94% of patients
– A reduction in pressure of 30% (or greater) at 12 months was achieved in 48-59% of patients
The effectiveness of SLT reduces over time.
Because the treatment creates no physical or destructive damage to the trabecular meshwork it can be repeated many times. However, every time SLT is repeated it is slightly less effective than the previous treatment.
SLT is very safe however like all medical treatments it is not 100% without risk. Adverse events are either very rare or of minimal severity.
Mild redness and/or ache may occur following the procedure may occur but nearly always settles within a few days. The duration of such problems is shortened by the standard use of anti-inflammatory eye drops after the procedure (an Ibuprofen-like eye drop four times per day for 4-7 days)
Photophobia (sensitivity to light) may also occur rarely. Again, this settles quickly with the standard post-procedure eye drops
A transient increase in eye pressure of >10mmHg occurs in 5.5% of patients. Eye drops (Apraclonidine) are specifically given before and immediately after the procedure to reduce this risk and your eye pressure is checked approximately 1 hour after the procedure. In the rare scenario that eye pressure does rise to unacceptable levels then a pressure reducing tablet will be given to you (Acetazolamide) which will bring eye pressure back to normal. For those particularly at risk of damage from such a pressure rise Acetazolamide may be given as a precaution before laser therapy to further reduce the risk of pressure rise.
Iris adhesions to the trabecular meshwork (“PAS”) can be caused by SLT. However, in the majority of safety studies a 0% rate was found. The highest recorded rate is 2% in one study only.
There are a few isolated reports of very rare events following SLT. Corneal oedema and macular oedema are possible but only a handful of single cases have ever been reported worldwide.
If you have any specific queries regarding SLT or any other treatment please make these known to Mr Lindfield and he can address these personally.