3. • Oosterhuis et all started this 1995.
• Transpupillary thermotherapy (TTT) is a technique in which low-level heat is
delivered through the pupil to the CHOROID AND RETINAL PIGMENT
EPITHELIUM using a modified diode laser.
• TTT currently being used in retinoblastoma, choroidal melanoma, classic and
occult choroidal neovascularization, which is a common cause of adult onset
blindness or age-related macular degeneration.
4. BASICS
• TTT based on Hyperthermia principle.
• 3 range can be used for tumour destruction.
– Low Range = 42-44 C (Helps potentiate radiotherapy)
– Intermediate Range = 45-60 C (Induces tumour necrosis , no coagulative
effect.)
– High Range = >60 C (Results in coaglative necrosis.
• Hyperthermia Systemic Heating
Localized Heating
– The success in TTT for CNV requires only occlusion of neovascular
vessel.
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8. CNV TREATMENT
• Heat energy is delivered slowly to choroid & retinal pigment epithelium
(RPE) using 810 nm diode laser.
• Laser spot size 1.2 , 2.0 , 3.0 mm.
• Laser Parameters used are
• Duration = 60-70 sec
• Power = 250-1000 mW
• (In general 3mm spot with 800 mW & appropriately reduced to smaller
spot size, Power density 10W/cm2).
• No Visible colour changes at end of treatment.
• Large diameter of radiation beam allows homogenous treatment of large
lesion.
9. • In pilot study of 16 eyes of 15 patient with subfoveal occult CNV
were treated with TTT.
• Of 16 eyes
– 19% (3) experienced improved VA by 2 or more lines.
– 56% (9) had no change in visual acuity
– 25% (4) had decline in VA.
– 94%(15) eyes had improvement in exudation.
– 1 eye showed persistant subretinal exudation.
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13. • THANK YOU EVERYONE FOR PATIENTLY LISTENING TO THIS PRESENTATION
• For feedbacks & brickbats plz mail at
• drdhir2014@gmail.com
D BEST WAY TO LEARN IS TO TEACH
