Panretinal Photocoagulation Protocol ISIS

1. G. Atma Vemulakonda, MD
Panretinal Photocoagulation
(PRP) - ISIS

2. Diabetes and Retinopathy
• Epidemiology:
– 18.2 million have DM and 5.8million don’t know they
have it
– Type 2 accounts for 95% of all DM cases
• Affects 8% of the population ≥ 20yo
• Affects 18.6% of the population ≥ 60yo
– Among the 10.2million ≥ 40yo and with known DM Prevalence
rates (as of the year 2000) of diabetic retinopathy:
• Diabetic retinopathy: 40.3% (4.1million people ≥ 40yo with known
DM)
• Vision-threatening Diabetic retinopathy: 82% (1 in every 12 persons
known to have DM has severe Vision-threatening Diabetic
retinopathy)

3. The Diabetic Retinopathy Study (DRS)
• DRS defined:
– Severe Nonprolifierative Diabetic Retinopathy
(NPDR):
• >20 intraretinal hemorrhages in all 4 quadrants
• Venous beading or loops in ≥ 2 quadrants
• Prominent intraretinal microvascular anomalies (IRMA) in ≥ 1
quadrant and no signs or proliferative diabetic retinopathy
(PDR)
IRMA
Venous Beading Venous Loop

4. The Diabetic Retinopathy Study (DRS)
• DRS defined:
– PDR:
• Neovascularization
• Pre-retinal or vitreous hemorrhage
• DRS determined that Severe NPDR and PDR
benefitted the most from PRP
IRMA

5. The Early Treatment of Diabetic
Retinopathy Study (ETDRS)
• ETDRS revealed:
– Early treatment (especially in Type 2 DM) reduces the
incidence of severe visual loss
• ETDRS defined: High Risk PDR
(3 of the following criteria must be met)
– Any NV
– Any NVD
– NVD ≥ std photo 10A
• = any NV, any NVD, and large amt NVD so qualifies
– NVE ≥ ½ DA
– Pre-retinal heme

6. General Safety
• Posted signs stating
laser in progress
• Laser off until ready
to treat
• Time out that
addresses
– Correct patient
• Two identifiers: eg name
and birthday or Med Rec
Number
– Correct eye
– Correct procedure

7. General Safety
• Wavelength appropriate goggles to those in the
laser suite not being treated
Used for the Green laser Used for the Infrared laser

8. PRP Characteristics (DRCR)
• The burn characteristics will be as follows: Size (on
retina) Argon laser using 200 micron spot size with
Rodenstock lens (or equivalent) or 500 micron spot size
with three mirror contact lens
• Exposure: 0.1 seconds recommended, 0.05 to 0.2
allowed
• # of Final Burns: 1200 to 1600
• Wavelength: Green or yellow (red can be used if vitreous
hemorrhage is present precluding use of green or
yellow)

9. PRP Burn Distribution
Posterior
border of
treatment
With current
wide field laser
lenses, laser
should be
applied as
anterior as
possible (but at
least to the
equator)
Extent: Arcades (~3000 microns from the
macular center) to at least the equator

10. • Intensity: Standard mild
white retinal burns
• Distribution: edges at least
1 burn width apart
– No closer than two rows
within the arcades
– No closer than two disc
diameters temporal to the
fovea
PRP Burn Characteristics
This photo was taken the same day as the
treatment, but not immediately after. As a result
there is some edema and increased laser spot
size compared to when it was first placed
Good spacing
Too close

11. PRP Lens Magnification
Distribution
Manufacturer Lens Image Mag Spot Size
Setting of
Laser
Actual Spot
size on
Retina
Mainster PRP 165 0.51 255 500
Volk SuperQuad 0.50 250 500
Volk Equator Plus 0.44 220 500
Volk Quad Ashperic 0.51 255 500
Volk TransEquator 0.70 350 500
Volk Area Centralis 1.06 530 500
Goldmann 3 mirror 1.06 500* 500
Rodenstock Panfundus 0.40 200 500
*500 microns has been used traditionally for the 3 Mirror lens, although the exact magnification equivalent is a 530 micron
spot size on the dial

12. Benefits of PRP
• DRS revealed:
– PRP demonstrated a 50% reduction in severe
visual loss
• (severe vision loss = 5/200 at 2 follow-up visits
scheduled at 4month intervals)

13. Risks Despite PRP
• Progression of PDR may occur despite PRP
leading to:
– Neovascularization
– Bleeding
– Preretinal fibrosis/traction
– Retinal detachment
– Visual loss

14. Common Side effects of Laser
• Glare and light sensitivity
• Ocular irritation
• ↓ peripheral vision with narrowed visual field
• Inflammation
• ↓ central vision from worsening macular edema
• ↓ accommodation
• ↓ dark adaptation

15. Uncommon Side effects of Laser
• Choroidal neovascularization
• Retinal breaks or detachments
• Hemorrhage
• Acute intraocular pressure rise(glaucoma)
• Corneal abrasion
• Cataract
*Uncommon complications may result in loss of vision, loss of globe or
need for further laser treatment or intraocular surgery

16. Types of Ocular Anesthesia
Used for PRP
• Topical
• Peribulbar injection
• Retrobulbar injection

17. Common Side Effects of
Anesthetic Injection
• Blurring of vision
• Numbness and swelling around the eye
• Ptosis (drooping of the eyelid)
• Diplopia (double vision)

18. Uncommon Side Effects of Anesthetic
Injection
• Retrobulbar or periorbital hemorrhage (bleeding behind or
around the eyeball)
• Globe perforation (puncture of the eyeball by the needle used
for anesthetic injection)
• Optic nerve injury or vascular damage (central retinal artery or
• vein occlusion)
• Allergic reaction to the anesthetic
• Seizure
• Cardiorespiratory arrest (death)
• Bilateral akinesia
*Uncommon complications may result in permanent loss of
vision,need for further surgery or treatment, or loss of the eye

19. Retinal Anatomy

20. Retinal Anatomy
Optic Nerve
Fovea

21. Retinal Anatomy
Posterior border of treatment

22. Retinal Anatomy
Avoid 3 and 9 if
possible as
this is normally
where the ciliary
nerves are

23. Retinal Anatomy
Remember that the image seen through the microscope is inverted and flipped