Intracameral DilationIntracameral Dilation(A Work in Progress)(A Work in Progress)

Steven Dewey, MDSteven Dewey, MDColorado Springs, COColorado Springs, CO

Consultant to AMOConsultant to AMORoyalties from MSTRoyalties from MST

With Significant Assistance from Nathan DeweyWith Significant Assistance from Nathan Dewey

Intracameral Dilation Intracameral Dilation RegimenRegimen

• Innovators in intracameral injections for dilationInnovators in intracameral injections for dilation– Cionni, et alCionni, et al11—IC lidocaine (supplemented with epinephrine)—IC lidocaine (supplemented with epinephrine)– Lundberg and BehndigLundberg and Behndig2,32,3—IC lidocaine, phenylephrine, and —IC lidocaine, phenylephrine, and

cyclopentolate, then IC lidocaine and phenylephrine without cyclopentolate, then IC lidocaine and phenylephrine without cyclocyclo

– Myers & Shugar—IC ”Epi-Shugarcaine” with preoperative Myers & Shugar—IC ”Epi-Shugarcaine” with preoperative tropicamidetropicamide

• Trends for intracameral injection: Trends for intracameral injection: – Faster acting agents (shorter half-life)Faster acting agents (shorter half-life)– Lidocaine is a common thread Lidocaine is a common thread

• Relaxes iris sphincterRelaxes iris sphincter– Parasympathetic antagonists Parasympathetic antagonists

• Tropicamide preoperativelyTropicamide preoperatively• Cyclopentolate intraoperativelyCyclopentolate intraoperatively

– Sympathetic agonists Sympathetic agonists • Epinephrine Epinephrine • Phenylephrine (Europe and Canada)Phenylephrine (Europe and Canada)

11Cionni, RJ; Barros, MG; Kaufman, AH; Osher, RH. Cataract surgery without preoperative eyedrops. J Cataract Refract Surg. 2003;29:2281–3. 22Lundberg B, Behndig A. Intracameral mydriatics in phacoemulsification cataract surgery. J Cataract Refract Surg 2003; 29:2366–23713 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. 44W. Myers, J. Shugar; Optimizing the intracameral dilation regimen for cataract surgery: Prospective randomized comparison W. 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):273-6of 2 solutions. J Cataract Refract Surg. 2009 Feb;35(2):273-6

The Weak Link in DilationThe Weak Link in Dilation

• Topical phenylephrine (PE) compared to Topical phenylephrine (PE) compared to intracameral epinephrineintracameral epinephrine– Is less potent at alpha receptors for dilationIs less potent at alpha receptors for dilation1,21,2

– Has far weaker beta-adrenergic effect to relax iris Has far weaker beta-adrenergic effect to relax iris sphinctersphincter3,43,4

– Longer half-life means slower onset of effectLonger half-life means slower onset of effect– Impedes the effectiveness of intracameral Impedes the effectiveness of intracameral

epinephrine by blocking iris receptorsepinephrine by blocking iris receptors• In patients on beta-blockers:In patients on beta-blockers:

– Systemic absorption can cause significant Systemic absorption can cause significant hypertension due to vasoconstriction from the hypertension due to vasoconstriction from the unopposed alpha-adrenergic effectunopposed alpha-adrenergic effect3,43,4 (can be seen (can be seen with calcium channel blockers as well)with calcium channel blockers as well)

– Beta-blockade extends to iris sphincter making the Beta-blockade extends to iris sphincter making the less-active PE a poorer choice for dilationless-active PE a poorer choice for dilation3,43,4

11Ohkobu K, Chiba S. Responses of isolated canine ophthalmic and ciliary arteries to vasoactive substances. Jpn J Ophthalmol. 1988;31:627-634. Ohkobu K, Chiba S. Responses of isolated canine ophthalmic and ciliary arteries to vasoactive substances. Jpn J Ophthalmol. 1988;31:627-634. 22Green K, Lollis G. Response of the isolated rabbit ciliary epithelium to adrenergic drugs following superior cervical ganglionectomy. Curr Eye Res. Green K, Lollis G. Response of the isolated rabbit ciliary epithelium to adrenergic drugs following superior cervical ganglionectomy. Curr Eye Res. 1982;1:217-222.1982;1:217-222. 33Geyer O; Bar-Ilan A; Beta3-adrenergic relaxation of bovine iris sphincter. FEBS letters 1998;429(3):356-8. 4 4 Katzung Bertram G Basic & Clinical Pharmacology Chapter 9, Pg 13355Kalyanaraman, 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. 66Groudine, 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.

Intracameral DilationIntracameral Dilation

• Based on previous research and Based on previous research and available compounded solutions:available compounded solutions:– Can we eliminate phenylephrine Can we eliminate phenylephrine

from the preoperative topical from the preoperative topical regimen?regimen?

– Can intracameral tropicamide Can intracameral tropicamide replace topical tropicamide? replace topical tropicamide?

– Does intracameral tropicamide Does intracameral tropicamide supplement topical tropicamide?supplement topical tropicamide?

Tested Regimens Tested Regimens (so far)(so far)

• IC Lidocaine IC Lidocaine – With cyclopentolate .1% and phenylephrine 1% (13m, 8f, With cyclopentolate .1% and phenylephrine 1% (13m, 8f,

ave 72.4 yo) (Note: Lundberg/Behndig solution contained ave 72.4 yo) (Note: Lundberg/Behndig solution contained 1.5% PE)1.5% PE)

• IC Lidocaine & Epinephrine (Epi-Shugarcaine)IC Lidocaine & Epinephrine (Epi-Shugarcaine)– Alone (9m, 15f, ave 74.5 yo) Alone (9m, 15f, ave 74.5 yo) – With topical tropicamide (5m, 9f, ave 72.1 yo)With topical tropicamide (5m, 9f, ave 72.1 yo)

• IC Tropicamide with Epi-ShugarcaineIC Tropicamide with Epi-Shugarcaine– With .1% intracameral tropicamide (8m, 23f, 71.6 yo)With .1% intracameral tropicamide (8m, 23f, 71.6 yo)– With topical and .05% intracameral tropicamide (10m, 8f, With topical and .05% intracameral tropicamide (10m, 8f,

ave 74.8 yo)ave 74.8 yo)– With topical and .1% intracameral tropicamide (3m, 4f, ave With topical and .1% intracameral tropicamide (3m, 4f, ave

71.6 yo)71.6 yo)• Each regimen was tested on a per day basisEach regimen was tested on a per day basis

– Fellow eye studies impractical when trying to evaluate a Fellow eye studies impractical when trying to evaluate a number of different combinations rather than a head-to-head number of different combinations rather than a head-to-head comparison of two different agents or combinations of comparison of two different agents or combinations of agentsagents

Measured Pupil DilationMeasured Pupil Dilation

• Using the “software ruler” of the Surgical Media Center Using the “software ruler” of the Surgical Media Center from Abbot Medical Optics, each of the following stages from Abbot Medical Optics, each of the following stages in cataract surgery was measured for each of the tested in cataract surgery was measured for each of the tested regimens. (seconds gives a rough interval after the regimens. (seconds gives a rough interval after the start of the case)start of the case)– At start of procedure (15 sec)At start of procedure (15 sec)– After first agent instillation (60 sec)After first agent instillation (60 sec)– After second agent instillation (90 sec)After second agent instillation (90 sec)– Viscomydriasis/Capsulorhexis (2 min)Viscomydriasis/Capsulorhexis (2 min)– Mid-Phacoemulsification (3 min)Mid-Phacoemulsification (3 min)– Mid-IOL insertion (5 min)Mid-IOL insertion (5 min)– End of Case (6 to 7 min)End of Case (6 to 7 min)

• Length of procedure also compared between regimensLength of procedure also compared between regimens– Speed of dilation will improve the efficiency of the surgerySpeed of dilation will improve the efficiency of the surgery– Effective pupil size and tone will speed the surgery as wellEffective pupil size and tone will speed the surgery as well

The Software RulerThe Software Ruler

Pre-dilation IC Epi-Shugarcaine IC Tropicamide .1%Pre-dilation IC Epi-Shugarcaine IC Tropicamide .1%

Capsulorhexis Phacoemulsification IOL Implantation End of CaseCapsulorhexis Phacoemulsification IOL Implantation End of Case

Intracameral Agents Intracameral Agents AloneAlone• Defined a failure to dilate at 6 mmDefined a failure to dilate at 6 mm

– Pupil did not achieve a 6 mm dilationPupil did not achieve a 6 mm dilation– Pupil did not maintain a 6 mm dilation from Pupil did not maintain a 6 mm dilation from

phacoemulsification to the end of the casephacoemulsification to the end of the case• IC cyclopentolate/PE failed in 6 of 21 (3m, 3f) cases IC cyclopentolate/PE failed in 6 of 21 (3m, 3f) cases

– Most billowing of the iris stromaMost billowing of the iris stroma• Epi-Shugarcaine dilated quickest, but failed in 8 of Epi-Shugarcaine dilated quickest, but failed in 8 of

24 cases (3m, 5f)24 cases (3m, 5f)– Although the pupil was a bit smaller, the iris tone was Although the pupil was a bit smaller, the iris tone was

goodgood• IC tropicamide .1% dilated slower, but was slightly IC tropicamide .1% dilated slower, but was slightly

more effective at retaining dilation combined with more effective at retaining dilation combined with Epi-Shugarcaine (8 of 31, 3m, 5f)Epi-Shugarcaine (8 of 31, 3m, 5f)– Slightly better dilation, iris tone equal to Epi-Slightly better dilation, iris tone equal to Epi-

Shugarcaine groupShugarcaine group

Benefits of Topical Benefits of Topical TropicamideTropicamide

Intracameral Agents Only

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• Topical tropicamide 1% improved all Topical tropicamide 1% improved all measured dilation parameters (38 of measured dilation parameters (38 of 39 successful) compared to 39 successful) compared to intracameral agents alone (p intracameral agents alone (p <.00005)<.00005)

• Viscomydriasis was effective with Viscomydriasis was effective with either dispersive viscoelastic used either dispersive viscoelastic used (Viscoat or Healon-D)(Viscoat or Healon-D)– Pre-op Tropicamide: 0.7 mmPre-op Tropicamide: 0.7 mm– No Pre Tropicamide: 1.1 mmNo Pre Tropicamide: 1.1 mm

• Regardless of dilation regimen, Regardless of dilation regimen, average pupil size decreased from average pupil size decreased from phacoemulsification to the end of phacoemulsification to the end of the casethe case– Average: .75 mmAverage: .75 mm

Topical and IC TropicamideTopical and IC Tropicamide

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• Topical tropicamide 1% improved Topical tropicamide 1% improved all measured dilation parameters all measured dilation parameters for Epi-Shugarcaine.for Epi-Shugarcaine.– p < .0001 for phaco, IOL and end-p < .0001 for phaco, IOL and end-

case measurementscase measurements

• Intracameral tropicamide Intracameral tropicamide improved dilation parameters for improved dilation parameters for Epi-ShugarcaineEpi-Shugarcaine– p < .06 for phacop < .06 for phaco– p < .05 for end-casep < .05 for end-case

• Intracameral tropicamide did not Intracameral tropicamide did not appear to supplement topical appear to supplement topical tropicamide in a statistically-tropicamide in a statistically-significant fashion, although significant fashion, although surgical case times were faster.surgical case times were faster.

Surgical Procedure Surgical Procedure TimesTimesBasically, procedure times were inversely Basically, procedure times were inversely

related to effectiveness of dilation.related to effectiveness of dilation.• IC Lidocaine & Epinephrine (Epi-IC Lidocaine & Epinephrine (Epi-

Shugarcaine)Shugarcaine)– With topical and .1% IC tropicamide: 6:18With topical and .1% IC tropicamide: 6:18– With topical and .05% IC tropicamide: 6:38With topical and .05% IC tropicamide: 6:38– With topical tropicamide: 6:42With topical tropicamide: 6:42– With .1% IC tropicamide: 6:49With .1% IC tropicamide: 6:49– Alone: 7:04Alone: 7:04

• IC Lidocaine IC Lidocaine – With cyclopentolate .1% and phenylephrine 1%: With cyclopentolate .1% and phenylephrine 1%:

7:267:26

ConclusionConclusion

• Intracameral dilation is effective for cataract Intracameral dilation is effective for cataract surgerysurgery– Epi-Shugarcaine is the key ingredientEpi-Shugarcaine is the key ingredient

• Topical phenylephrine is not necessary on a Topical phenylephrine is not necessary on a routine basisroutine basis

• Topical tropicamide 1 % enhances the effects Topical tropicamide 1 % enhances the effects of all tested intracameral agentsof all tested intracameral agents– Intracameral tropicamide may provide some Intracameral tropicamide may provide some

benefitbenefit

• But, physiology will remain variable between But, physiology will remain variable between individuals despite our efforts at individuals despite our efforts at standardizationstandardization