Download Intracameral Dilation

Intracameral Dilation
(Still A Work in Progress)
Steven Dewey, MD
Colorado Springs, CO
Consultant to AMO
Royalties from MST
With Significant Assistance from Nathan Dewey
Intracameral Dilation Regimen
• Innovators in intracameral injections for dilation
– Cionni, et al1—IC lidocaine (supplemented with epinephrine)
– Lundberg and Behndig —IC lidocaine, phenylephrine, and
cyclopentolate, then IC lidocaine and phenylephrine without cyclo
– Myers & Shugar—IC ”Epi-Shugarcaine” with preoperative tropicamide
2,3
• Trends for intracameral injection:
– Faster acting agents (shorter half-life)
– Lidocaine is a common thread
• Relaxes iris sphincter
– Parasympathetic antagonists
• Tropicamide preoperatively
• Cyclopentolate intraoperatively
– Sympathetic agonists
• Epinephrine
• Phenylephrine (Europe and Canada)
RJ; Barros, MG; Kaufman, AH; Osher, RH. Cataract surgery without preoperative eyedrops. J Cataract Refract Surg. 2003;29:2281–3.
B, Behndig A. Intracameral mydriatics in phacoemulsification cataract surgery. J Cataract Refract Surg 2003; 29:2366–2371
3 Lundberg B, Behndig A. Separate and additive mydriatic effects of lidocaine hydrochloride, phenylephrine, and cyclopentolate after
intracameral injection. J Cataract Refract Surg. 2008 Feb;34(2):280-3.
4W. Myers, J. Shugar; Optimizing the intracameral dilation regimen for cataract surgery: Prospective randomized comparison of 2 solutions. J
Cataract Refract Surg. 2009 Feb;35(2):273-6
1Cionni,
2Lundberg
The Weak Link in Dilation
• Topical phenylephrine (PE) compared to intracameral
epinephrine
–
–
–
–
Is less potent at alpha receptors for dilation1,2
Has far weaker beta-adrenergic effect to relax iris sphincter3,4
Longer half-life means slower onset of effect
Impedes the effectiveness of intracameral epinephrine by
blocking iris receptors
• In patients on beta-blockers:
– Systemic absorption can cause significant hypertension due
to vasoconstriction
from the unopposed alpha-adrenergic
3,4
effect (can be seen with calcium channel blockers as well)
– Beta-blockade extends to iris sphincter
making the less-active
3,4
PE a poorer choice for dilation
1Ohkobu
K, Chiba S. Responses of isolated canine ophthalmic and ciliary arteries to vasoactive substances. Jpn J Ophthalmol. 1988;31:627-634.
K, Lollis G. Response of the isolated rabbit ciliary epithelium to adrenergic drugs following superior cervical ganglionectomy. Curr Eye Res. 1982;1:217-222.
3Geyer O; Bar-Ilan A; Beta3-adrenergic relaxation of bovine iris sphincter. FEBS letters 1998;429(3):356-8.
4 Katzung Bertram G Basic & Clinical Pharmacology Chapter 9, Pg 133
5Kalyanaraman, M., et al., Cardiopulmonary compromise after use of topical and submucosal alpha- agonists: possible added complication by the use of beta-blocker therapy.
Otolaryngol Head Neck Surg, 1997. 117(1): p. 56-61.
6Groudine, S.B., et al., New York State guidelines on the topical use of phenylephrine in the operating room. The Phenylephrine Advisory Committee. Anesthesiology, 2000.
92(3): p. 859-64.
2Green
Intracameral Dilation
(2009) A non-matched study found the following:
– We can eliminate phenylephrine from the preoperative topical regimen
– We can’t use intracameral tropicamide to replace topical tropicamide.
– But, intracameral tropicamide may supplement topical tropicamide.
(2010) Based on these findings, consideration was given to the following
subjective/objective observations
– Diluted lidocaine did not provide as effective anesthesia 1% lidocaine
– Diluted epinephrine did not stabilize the stroma as effectively
The following regimen was created:
• IC Tropicamide .1% with 1% Lidocaine and half-strength Epinephrine
– Supplemented by pre-operative topical 1% tropicamide (“IC Tropicamide Mix”)
•
•
•
•
•
(compounded .2% tropicamide and 2% lidocaine mixed 50:50 with non-preserved epinephrine)
Compared in a fellow eye study to preoperative topical 1% Cyclopentolate and 10%
Phenylephrine (with 1% IC Lidocaine) (“Topical Drops”)
24 patients (11F, 13M), ave age 73.8 (+/- 7.3 yrs)
All surgeries carried out between October, 2009 and March, 2010 and spaced no more
than one month apart.
Although tamsulosin was not specifically evaluated in the study, two patients were
dropped from the evaluation for starting tamsulosin between the performance of the
two surgeries. (Neither informed our office specifically, but one notified the surgery
center upon arrival)
The assumption is that all other medications were the same between the two surgeries
(and gender as well . . .)
Tested Regimens
(so far)
(2009) Intracameral Regimen Study
• IC Lidocaine
–
With cyclopentolate .1% and phenylephrine 1% (13m, 8f, ave 72.4 yo) (Note:
Lundberg/Behndig solution contained 1.5% PE)
• IC Lidocaine & Epinephrine (Epi-Shugarcaine)
–
–
Alone (9m, 15f, ave 74.5 yo)
With topical tropicamide (5m, 9f, ave 72.1 yo)
–
–
–
With .1% intracameral tropicamide (8m, 23f, 71.6 yo)
With topical and .05% intracameral tropicamide (10m, 8f, ave 74.8 yo)
With topical and .1% intracameral tropicamide (3m, 4f, ave 71.6 yo)
–
Fellow eye studies impractical when trying to evaluate a number of different
combinations rather than a head-to-head comparison of two different agents
or combinations of agents
• IC Tropicamide with Epi-Shugarcaine
• Each regimen was tested on a per day basis
(2010) Fellow Eye Study (11f, 13m, ave 73.8 yo)
• Compounded Topical Drops
–
–
1% Cyclopentolate & 10% Phenylephrine
Supplemented with 1% IC Lidocaine
–
Supplemented by pre-operative topical 1% tropicamide
• IC Tropicamide .1% with 1% Lidocaine and half-strength Epinephrine
Measuring Pupil Dilation
• Using the “software ruler” of the Surgical Media Center (SMC) from
Abbot Medical Optics, each of the following stages in cataract surgery
was measured for each of the tested regimens. (seconds gives a rough
interval after the start of the case)
–
–
–
–
–
–
–
At start of procedure (15 sec)
After first agent instillation (60 sec)
After second agent instillation (90 sec) (2009 testing only)
Viscomydriasis/Capsulorhexis (2 min)
Mid-Phacoemulsification (3 min)
Mid-IOL insertion (5 min)
End of Case (6 to 7 min)
–
–
Speed of dilation will improve the efficiency of the surgery
Effective pupil size and tone will speed the surgery as well
• Length of procedure also compared between regimens
• Cases were eliminated in 2009 and 2010 if the pupil size was not
captured for accurate measurement
–
–
Surgical case too far off-screen
Video did not get started, or did not get started on time
The SMC Software Ruler
Pre-dilation
Capsulorhexis
IC Epi-Shugarcaine
Phacoemulsification
IC Tropicamide .1%
IOL Implantation
End of Case
Relative Dilation Failures
Defined a failure to dilate at 6 mm (an arbitrary measurement based on optic diameter)
– Pupil did not achieve a 6 mm dilation
– Pupil did not maintain a 6 mm dilation from phacoemulsification to the end of
the case
2009 Intracameral Dilation Study
• IC cyclopentolate/PE failed in 6 of 21 (3m, 3f) cases
–
Most billowing of the iris stroma of any regimen
–
Although the pupil was a bit smaller, the iris tone was good
–
Slightly better dilation, iris tone equal to Epi-Shugarcaine group
•
Epi-Shugarcaine dilated quickest, but failed in 8 of 24 cases (3m, 5f)
•
IC tropicamide .1% dilated slower, but was slightly more effective at retaining
dilation combined with Epi-Shugarcaine (8 of 31, 3m, 5f)
2010 Fellow-Eye Study
• Topical drops alone failed in 1 of 24 (1m) with 5 (4m, 1f) at less than 6 mm by the
end of the case
• IC Tropicamide mix failed in 2 of 24 (3m, 2f) with 6 (5m, 1f) at less than 6 mm by
the end of the case
• The single failure in each series to reach 6 mm at any point were fellow eyes of the
same patient (male), however, only three below 6 mm at the end of the case were
fellow eyes (3m)
No surgical case in either 2009 or 2010 required a pupil-expanding device or pupil
stretching, nor were any eliminated from the study for that reason.
Benefits of Topical Tropicamide
• Topical tropicamide 1% improved
Intracameral Agents Only
9
8
Pupil Size (cm)
7
6
Lido - Epi
5
Trop - L/E
4
Lido - Cyclo/Phenyl
3
2
1
0
Start
First IC
Second
IC
Rhexis
Phaco
IOL
End
– Pre-op Tropicamide: 0.7 mm
– No Pre Tropicamide: 1.1 mm
Preoperative Tropicamide 1% (One Drop)
9
• Regardless of dilation regimen,
8
7
Pupil Size (cm)
all measured dilation parameters
(38 of 39 successful) compared
to intracameral agents alone (p
<.00005)
• Viscomydriasis was effective with
either dispersive viscoelastic used
(Viscoat or Healon-D)
6
Lido - Epi
5
L/E - Trop .05%
Trop .1% - L/E
4
3
average pupil size decreased from
phacoemulsification to the end of
the case
– Average: .75 mm
2
1
0
Start
First IC
Second IC
Rhexis
Phaco
IOL
End
Topical and IC Tropicamide
Intracameral Lidocaine / Epinepherine
• (2009) Topical tropicamide 1% improved
9
all measured dilation parameters for EpiShugarcaine.
8
7
–
Pupil Size (cm)
6
5
No Tropicamide
Tropicamide 1%
4
3
1
–
–
0
Start
Lido
Epi
Rhexis
Phaco
IOL
End
9
8
7
6
IC Tropic - IC L/E
PreOp Tropic - IC L/E
5
p < .06 for phaco
p < .05 for end-case
• (2009) Intracameral tropicamide did not
PreOp and/or IC Tropicamide
Pupil Size (cm)
• (2009) Intracameral tropicamide improved
dilation parameters for Epi-Shugarcaine
2
PreOp & IC Tropic - IC L/E
appear to supplement topical tropicamide
in a statistically-significant fashion,
although surgical case times were faster
than without it.
–
4
3
Hence, the 2010 study
• (2010) The IC Tropicamide Mix resulted in
2
dilation close to that of Topical Drops.
1
0
Start
IC Trop
.1%
IC
Lido/Epi
Rhexis
Phaco
IOL
–
End
Topical vs. Intracameral Tropicamide Mix
9
8
–
7
Pupil Dilation (mm)
p < .0001 for phaco, IOL and end-case
measurements
6
5
Topical Drops
Intracameral Tropicamide Mix
4
Starting dilation was obviously different (p
= .00029), as was pupil size just prior to
viscoelastic inflation of the anterior
chamber (p = .08)
For capsulorhexis, phacoemulsification, IOL
implantation and end of case, the dilation
was virtually the same (p = .11 to .27)
• (2010) No significant differences in iris
tone were recorded between the two
groups.
3
2
1
0
Start
IC
Visco
Phaco
IOL
End
Surgical Procedure Times
Procedure times were measured from first incision to completion of the
surgery
(2009) Procedure times were inversely related to effectiveness of dilation.
• IC Lidocaine & Epinephrine (Epi-Shugarcaine)
–
–
–
–
–
With topical and .1% IC tropicamide: 6:18
With topical and .05% IC tropicamide: 6:38
With topical tropicamide: 6:42
With .1% IC tropicamide: 6:49
Alone: 7:04
–
With cyclopentolate .1% and phenylephrine 1%: 7:26
• IC Lidocaine
(2010) The current study compared standard topical drops to the specified
intracameral mixture (one step eliminated from 2009 study, probably 20
to 30 seconds):
• IC Lidocaine 1%, Tropicamide .1% & half-strength Epinephrine
–
With pre-operative tropicamide: 5:24 (std dev 49s)
–
With IC Lidocaine: 5:17 (std dev 61s)
• Topical 1% Cyclopentolate/10% Phenylephrine
• The two tested regimens had no difference in surgical case time, p = .33,
suggesting no delay in allowing IC agents to work, nor a significant
difference in iris characteristics to influence surgical time.
Conclusions (So Far)
• Intracameral dilation is effective for cataract surgery
– No significant differences in dilation compared to topical drops
– No differences in surgical case times
• IC agents work quickly (no delay)
• Iris behavior similar to topical agents
– Subjective absence of stinging from topical drops is a benefit
– Topical phenylephrine is not necessary on a routine basis
• Higher concentration of epinephrine has an improved effect
• Pre-operative topical tropicamide 1% enhances the effects of
all tested intracameral agents
– IC Tropicamide appears to enhance this effect
• But, physiology will remain variable between individuals
despite our efforts at standardization
– Very difficult to standardize exposure time of pre-operative
topical agents
– Standard topical drops do sting and the resulting epiphora may
dilute the effect of these drops