Ignite Creation Date:
2024-05-05 @ 4:56 PM
Last Modification Date:
2024-10-26 @ 9:26 AM
Study NCT ID:
NCT00346138
Status:
COMPLETED
Last Update Posted:
2010-01-15
First Post:
2006-06-27
Brief Title:
A Comparison Between Full Thickness and Partial Thickness Corneal Transplantation for Corneal Edema
Sponsor:
Mayo Clinic
Organization:
Mayo Clinic
Study Overview
Official Title:
Deep Lamellar Endothelial Keratoplasty as Surgical Treatment for Corneal Endothelial Decompensation
Status:
COMPLETED
Status Verified Date:
2010-01
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
The objectives of this study are to compare the visual and refractive outcomes of deep lamellar endothelial keratoplasty DLEK with penetrating keratoplasty as treatment for certain cases of corneal edema due to endothelial decompensation Additionally data will be collected to compare corneal shape corneal thickness endothelial cell density keratocyte density corneal sensitivity light scatter and subjective visual function between the two procedures
Detailed Description:
This will be a randomized prospective study We will enroll patients using the following inclusion and exclusion criteria based upon the surgeons initial complete ophthalmic examination which includes refraction keratometry slit lamp examination intraocular pressure and corneal thickness measurement and dilated fundus examination
Inclusion criteria
1 Both males and females are eligible 2 Patient age 21 years or older 3 Corneal edema due to endothelial dysfunction 4 Aphakia pseudophakia or cataract requiring extraction 5 Visual acuity as measured in standardized fashion ETDRS chart and appropriate illumination
1 Study eye best spectacle-corrected entrance acuity 2040 or worse
2 Contralateral eye best spectacle-corrected entrance acuity equal to or better than the study eye and 20200 or better
Exclusion criteria
1 Central stromal corneal scars 2 Presence of a filtering bleb 3 History of Herpes simplex or Herpes zoster keratitis 4 Uncontrolled glaucoma 5 Pregnancy Serum pregnancy testing will be performed within 7 days prior to surgery for women of child-bearing potential
In the 2-year period January 2001 to January 2003 67 PKs were performed at Mayo Clinic for endothelial dysfunction eg Fuchs dystrophy or pseudophakic corneal edema in patients who met the entry criteria for this protocol During the 2-year enrollment period of this study we anticipate that up to 50 patients will be enrolled Appropriate counseling will be done including a discussion of the potential benefits and risks of the procedures IRB-approved consent forms will be signed Enrolled patients will return on a different day often the day before surgery or the morning of surgery to be performed in the afternoon for the preoperative Keratogram Randomization and assignment of the patient to DLEK or PK will occur after the preoperative Keratogram and after the surgeon has accepted a donor cornea from the eye bank for the procedure
Keratogram
The Keratogram consists of a series of tests administered both pre- and post-operatively by trained research personnel who are masked to the patients particular randomizations Keratograms will be performed preoperatively and at 1 month 3-6 weeks 3 months 2-4 months 6 months 5-7 months and 1 2 and 3 years 616173 months postoperatively The following measurement procedures to be conducted only on the operated eye are included in each Keratogram The equipment to be used is included in parentheses
1 Contrast sensitivity with best refraction Ginsburg contrast sensitivity tester 2 Straylight meter measurement Van den Berg straylight meter 3 Corneal topography map TMS-2 4 Corneal profile Orbscan 5 Noncontact endothelial photography Konan Robo 6 Scatterometry Mayo scatterometer 7 Corneal esthesiometry Belmonte esthesiometer 8 Confocal microscopy Tandem Scanning or Confoscan 3 confocal microscope 9 Quality of visual function questionnaire NEI-VFQ This will not be done at the 1week one month or 3 month visit
Eligibility of Fellow Eyes Fellow eyes in bilateral cases will be eligible to enter the study 4 months or more after the first procedure if these eyes now meet the eligibility criteria ie if the fellow eye now has worse vision than the operated study eye These eyes will be randomized separately and follow the same protocol with the exception that the patient may override the randomization if he or she prefers to have one or the other of the 2 procedures For data analysis fellow eyes will be considered a separate group
Adverse Occurrences For DLEK adverse occurrences at the time of surgery such as premature entry into the anterior chamber during recipient lamellar dissection will require conversion to a standard PK and the patient will be exited from the study Adverse postoperative occurrences in either surgical group such as a dislocated disc uncontrolled rejection primary graft failure infection or other adverse events will be managed by the surgeon according to standard practices These patients will remain in the study and will have identical follow-up
SURGICAL METHODS
1 DLEK
Anesthesia
Anesthesia options will include monitored attended local anesthesia or general orotracheal anesthesia depending on the particular patients desire and comorbid conditions For local anesthesia a standard retrobulbar and facial nerve block as done for standard PK will be utilized
Preparation of recipient
1 In the preoperative area pilocarpine 1 one drop to operated eye is instilled every five minutes for 3 doses in order to constrict the pupil
2 After anesthesia is attained and the eye is prepared and draped the lid speculum and operating microscope with video recording of each case is brought into position
3 Rectus bridle sutures for positioning of the globe are placed as necessary
4 A limbal peritomy is performed and the conjunctiva is recessed from the 930 to 230 oclock superior limbus
5 A limbal incision of the sclera 10 mm peripheral to the limbus and parallel to the limbus is made with a guarded diamond knife set to 035 mm depth The length of the incision is 90 mm or 45mm measured with calipers
6 Deep lamellar dissection of the cornea utilizing a crescent blade is performed followed by a stromal dissector spatula
7 Paracentesis and Healon injection to maintain the anterior chamber
8 Placement of intra-lamellar trephine with trephination of the recipient posterior stromal disc If a 45mm incision was made then the trephine is used to make an indentation on the corneal surface and the posterior lamellar disc is cut with scissors
9 Entry into anterior chamber with a diamond blade at 12 oclock in the trephination
10 Excision of recipient posterior stromal disc and endothelium with corneal scissors and removal of disc from the eye
11 Caliper measurement of the diameter of the excised tissue is recorded
12 Wound closure and standard phacoemulsification and IOL implantation through a separate incision in patients requiring cataract removal
13 Healon is evacuated completely from the anterior chamber with an IA unit eg Simcoe Needle
14 The cornea is covered with a moistened gauze disc
Preparation of donor tissue
1 Donor corneo-scleral tissue is removed from the storage media endothelium is coated with healon and the tissue is secured in the Moria artificial anterior chamber
2 A deep lamellar dissection pocket is formed in the donor with a crescent blade followed by a stromal dissector spatula
3 The donor tissue is placed endothelial side up onto the trephination block and the same size trephine same size as recipient disc tissue diameter is used to trephine the donor disc
4 The donor disc is separated from the corneo-scleral donor tissue and placed endothelial side down or folded in half if a 45mm incision was made onto a healon coated transfer spatula
Transfer of donor to recipient
1 Air is injected into the anterior chamber 2 The donor tissue disc is placed into the anterior chamber through the lamellar incision
4 The spatula is removed from the eye by sliding out from under the Healon coating
5 The disc position is finely manipulated with a needle or hook as needed taking care to minimize endothelial touch
5 The limbal wound is sutured with interrupted 10-0 nylon sutures 6 The anterior chamber air bubble is replaced 50 with balanced salt solution 7 A Seidel test is performed If positive additional limbal sutures are placed
8 The conjunctiva is closed with cautery or sutures 9 Subconjunctival dexamethasone 2 mg or Solu-Medrol 30 mg and cefazolin 25 mg or gentamicin 20 mg are injected in the inferior fornix The eye is bandaged with a gauze patch and a Fox shield
10 The patient is instructed to spend the next two postoperative hours in a supine position
11 Routine postoperative orders for corneal transplantation are given upon discharge from the hospital that day
PK The surgical method for patients randomized to penetrating keratoplasty will be the standard procedure currently practiced by the participating surgeons
POSTOPERATIVE CARE The patient will be seen the day after the surgery Postoperative medications will include topical antibiotic of the surgeons choice twice daily for one to two weeks and prednisolone acetate 1 four times daily The steroid drop will be tapered by one drop daily each month Alterations to the steroid taper and other medical treatment will be made based upon individual patient conditions and response Patient activity restrictions and eye protection measures will follow the usual PK recommendations by the individual surgeon All patients will be seen at the following intervals preoperatively and at 1 week 5-14 days 1 month 3-6 weeks 3 months 4-6 months 6 months 5-7 months and 1 2 and 3 years 616173 months postoperatively Keratograms will be performed at each visit except one day and one week postoperatively Confocal microscopy will be done as part of each keratogram and also at the one week postoperative visit Additional clinic visits may be requested by the surgeon as needed for proper medical management Corneal suture removal in penetrating grafts or limbal suture removal in DLEK will be dictated by patient healing and at the surgeons discretion
DATA COLLECTION AND STATISTICAL ANALYSIS Data collection will be performed with the instruments and schedule delineated above in the Methods section The following outcome measures will be calculated from the data These will be compared between the 2 groups DLEK and PK at each postoperative time by using t-tests or rank sum tests with Bonferroni corrections
Primary Outcome Measures
1 Visual acuity with best refractive correction
2 Refractive astigmatism
3 Keratometric astigmatism
4 Topographic astigmatism Simulated Keratometry function of the TMS-1 mapping Secondary Outcome Measures
-- --
1 Corneal backscattered light
2 Ocular forward-scattered light
3 Contrast sensitivity
4 Posterior corneal curvature
5 Corneal sensitivity
6 Corneal subbasal nerve density
7 Keratocyte density
8 Endothelial cell density
9 Quality of visual function NEI-VFQ Statistical Power We have recently published variance data on keratometric astigmatism and endothelial cell density after PK The keratometric astigmatism17 after removal of all sutures was 46 61617 27 D mean61617SD and the endothelial cell density18 2 months postoperatively was 2606 61617 446 cellsmm2 To detect 61537005 a difference of 25 D in keratometric astigmatism with 80 certainty 6153802 would require 20 subjects in each group and to detect a difference of 400 cellsmm2 in endothelial cell density would require 20 subjects in each group We expect to have 25 patients in each group giving the study adequate power
For an additional use of the data primary outcome data on the patients randomized to DLEK from our center will be pooled with data from other participating centers in the Endothelial Keratoplasty Group organized by Mark Terry MD Portland OR who will coordinate data collection and statistical analysis Pooled data will be used to calculate mean postoperative visual acuity refractive outcomes and frequency of favorable outcome These data will be compared with published data on PK
Inclusion criteria
1 Both males and females are eligible 2 Patient age 21 years or older 3 Corneal edema due to endothelial dysfunction 4 Aphakia pseudophakia or cataract requiring extraction 5 Visual acuity as measured in standardized fashion ETDRS chart and appropriate illumination
1 Study eye best spectacle-corrected entrance acuity 2040 or worse
2 Contralateral eye best spectacle-corrected entrance acuity equal to or better than the study eye and 20200 or better
Exclusion criteria
1 Central stromal corneal scars 2 Presence of a filtering bleb 3 History of Herpes simplex or Herpes zoster keratitis 4 Uncontrolled glaucoma 5 Pregnancy Serum pregnancy testing will be performed within 7 days prior to surgery for women of child-bearing potential
In the 2-year period January 2001 to January 2003 67 PKs were performed at Mayo Clinic for endothelial dysfunction eg Fuchs dystrophy or pseudophakic corneal edema in patients who met the entry criteria for this protocol During the 2-year enrollment period of this study we anticipate that up to 50 patients will be enrolled Appropriate counseling will be done including a discussion of the potential benefits and risks of the procedures IRB-approved consent forms will be signed Enrolled patients will return on a different day often the day before surgery or the morning of surgery to be performed in the afternoon for the preoperative Keratogram Randomization and assignment of the patient to DLEK or PK will occur after the preoperative Keratogram and after the surgeon has accepted a donor cornea from the eye bank for the procedure
Keratogram
The Keratogram consists of a series of tests administered both pre- and post-operatively by trained research personnel who are masked to the patients particular randomizations Keratograms will be performed preoperatively and at 1 month 3-6 weeks 3 months 2-4 months 6 months 5-7 months and 1 2 and 3 years 616173 months postoperatively The following measurement procedures to be conducted only on the operated eye are included in each Keratogram The equipment to be used is included in parentheses
1 Contrast sensitivity with best refraction Ginsburg contrast sensitivity tester 2 Straylight meter measurement Van den Berg straylight meter 3 Corneal topography map TMS-2 4 Corneal profile Orbscan 5 Noncontact endothelial photography Konan Robo 6 Scatterometry Mayo scatterometer 7 Corneal esthesiometry Belmonte esthesiometer 8 Confocal microscopy Tandem Scanning or Confoscan 3 confocal microscope 9 Quality of visual function questionnaire NEI-VFQ This will not be done at the 1week one month or 3 month visit
Eligibility of Fellow Eyes Fellow eyes in bilateral cases will be eligible to enter the study 4 months or more after the first procedure if these eyes now meet the eligibility criteria ie if the fellow eye now has worse vision than the operated study eye These eyes will be randomized separately and follow the same protocol with the exception that the patient may override the randomization if he or she prefers to have one or the other of the 2 procedures For data analysis fellow eyes will be considered a separate group
Adverse Occurrences For DLEK adverse occurrences at the time of surgery such as premature entry into the anterior chamber during recipient lamellar dissection will require conversion to a standard PK and the patient will be exited from the study Adverse postoperative occurrences in either surgical group such as a dislocated disc uncontrolled rejection primary graft failure infection or other adverse events will be managed by the surgeon according to standard practices These patients will remain in the study and will have identical follow-up
SURGICAL METHODS
1 DLEK
Anesthesia
Anesthesia options will include monitored attended local anesthesia or general orotracheal anesthesia depending on the particular patients desire and comorbid conditions For local anesthesia a standard retrobulbar and facial nerve block as done for standard PK will be utilized
Preparation of recipient
1 In the preoperative area pilocarpine 1 one drop to operated eye is instilled every five minutes for 3 doses in order to constrict the pupil
2 After anesthesia is attained and the eye is prepared and draped the lid speculum and operating microscope with video recording of each case is brought into position
3 Rectus bridle sutures for positioning of the globe are placed as necessary
4 A limbal peritomy is performed and the conjunctiva is recessed from the 930 to 230 oclock superior limbus
5 A limbal incision of the sclera 10 mm peripheral to the limbus and parallel to the limbus is made with a guarded diamond knife set to 035 mm depth The length of the incision is 90 mm or 45mm measured with calipers
6 Deep lamellar dissection of the cornea utilizing a crescent blade is performed followed by a stromal dissector spatula
7 Paracentesis and Healon injection to maintain the anterior chamber
8 Placement of intra-lamellar trephine with trephination of the recipient posterior stromal disc If a 45mm incision was made then the trephine is used to make an indentation on the corneal surface and the posterior lamellar disc is cut with scissors
9 Entry into anterior chamber with a diamond blade at 12 oclock in the trephination
10 Excision of recipient posterior stromal disc and endothelium with corneal scissors and removal of disc from the eye
11 Caliper measurement of the diameter of the excised tissue is recorded
12 Wound closure and standard phacoemulsification and IOL implantation through a separate incision in patients requiring cataract removal
13 Healon is evacuated completely from the anterior chamber with an IA unit eg Simcoe Needle
14 The cornea is covered with a moistened gauze disc
Preparation of donor tissue
1 Donor corneo-scleral tissue is removed from the storage media endothelium is coated with healon and the tissue is secured in the Moria artificial anterior chamber
2 A deep lamellar dissection pocket is formed in the donor with a crescent blade followed by a stromal dissector spatula
3 The donor tissue is placed endothelial side up onto the trephination block and the same size trephine same size as recipient disc tissue diameter is used to trephine the donor disc
4 The donor disc is separated from the corneo-scleral donor tissue and placed endothelial side down or folded in half if a 45mm incision was made onto a healon coated transfer spatula
Transfer of donor to recipient
1 Air is injected into the anterior chamber 2 The donor tissue disc is placed into the anterior chamber through the lamellar incision
4 The spatula is removed from the eye by sliding out from under the Healon coating
5 The disc position is finely manipulated with a needle or hook as needed taking care to minimize endothelial touch
5 The limbal wound is sutured with interrupted 10-0 nylon sutures 6 The anterior chamber air bubble is replaced 50 with balanced salt solution 7 A Seidel test is performed If positive additional limbal sutures are placed
8 The conjunctiva is closed with cautery or sutures 9 Subconjunctival dexamethasone 2 mg or Solu-Medrol 30 mg and cefazolin 25 mg or gentamicin 20 mg are injected in the inferior fornix The eye is bandaged with a gauze patch and a Fox shield
10 The patient is instructed to spend the next two postoperative hours in a supine position
11 Routine postoperative orders for corneal transplantation are given upon discharge from the hospital that day
PK The surgical method for patients randomized to penetrating keratoplasty will be the standard procedure currently practiced by the participating surgeons
POSTOPERATIVE CARE The patient will be seen the day after the surgery Postoperative medications will include topical antibiotic of the surgeons choice twice daily for one to two weeks and prednisolone acetate 1 four times daily The steroid drop will be tapered by one drop daily each month Alterations to the steroid taper and other medical treatment will be made based upon individual patient conditions and response Patient activity restrictions and eye protection measures will follow the usual PK recommendations by the individual surgeon All patients will be seen at the following intervals preoperatively and at 1 week 5-14 days 1 month 3-6 weeks 3 months 4-6 months 6 months 5-7 months and 1 2 and 3 years 616173 months postoperatively Keratograms will be performed at each visit except one day and one week postoperatively Confocal microscopy will be done as part of each keratogram and also at the one week postoperative visit Additional clinic visits may be requested by the surgeon as needed for proper medical management Corneal suture removal in penetrating grafts or limbal suture removal in DLEK will be dictated by patient healing and at the surgeons discretion
DATA COLLECTION AND STATISTICAL ANALYSIS Data collection will be performed with the instruments and schedule delineated above in the Methods section The following outcome measures will be calculated from the data These will be compared between the 2 groups DLEK and PK at each postoperative time by using t-tests or rank sum tests with Bonferroni corrections
Primary Outcome Measures
1 Visual acuity with best refractive correction
2 Refractive astigmatism
3 Keratometric astigmatism
4 Topographic astigmatism Simulated Keratometry function of the TMS-1 mapping Secondary Outcome Measures
-- --
1 Corneal backscattered light
2 Ocular forward-scattered light
3 Contrast sensitivity
4 Posterior corneal curvature
5 Corneal sensitivity
6 Corneal subbasal nerve density
7 Keratocyte density
8 Endothelial cell density
9 Quality of visual function NEI-VFQ Statistical Power We have recently published variance data on keratometric astigmatism and endothelial cell density after PK The keratometric astigmatism17 after removal of all sutures was 46 61617 27 D mean61617SD and the endothelial cell density18 2 months postoperatively was 2606 61617 446 cellsmm2 To detect 61537005 a difference of 25 D in keratometric astigmatism with 80 certainty 6153802 would require 20 subjects in each group and to detect a difference of 400 cellsmm2 in endothelial cell density would require 20 subjects in each group We expect to have 25 patients in each group giving the study adequate power
For an additional use of the data primary outcome data on the patients randomized to DLEK from our center will be pooled with data from other participating centers in the Endothelial Keratoplasty Group organized by Mark Terry MD Portland OR who will coordinate data collection and statistical analysis Pooled data will be used to calculate mean postoperative visual acuity refractive outcomes and frequency of favorable outcome These data will be compared with published data on PK
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None