Fixing Epithelial Basement Membrane Dystrophy

[kurt]

How can epithelial basement membrane dystrophy be fixed?

If it is seen following post-LASIK, how can it be deduced whether it existed prior to LASIK, if it was, say, asymptomatic?

Originally Posted by kurt

How can epithelial basement membrane dystrophy be fixed?

If it is seen following post-LASIK, how can it be deduced whether it existed prior to LASIK, if it was, say, asymptomatic?

The standard "fix" for epithelial basement membrane dystrophy is debridement. Of the available methods of debridement, PTK (or PRK) appears to be the most effective, followed by diamond keratectomy, followed by simple mechanical debridement.

The simplest way to detect EBMD is by slit lamp observation aided by fluorescein. EBMD has other names, such as map dot or fingerprint dystrophy, after the patterns formed by the uneven epithelium. I have also heard and read that the various forms can morph into one another, and at times present no outward signs. Symptoms "may" include dry eye symptoms resulting from low TBUT. Some doctors will "test" the adhesion of the epithelium using a cotton-tipped applicator prior to surgery, and say that if the epithelium seems "loosely adherent," then they do not proceed with LASIK. I doubt this is standard practice.

DrG

[Rebecca Petris]

At a session on complications prevention & management at ESCRS the other day, John Kanellopoulos talked a bit about EBMD. - He laid a lot of stress on the importance of prevention, and, interestingly, said that the best way to make sure at-risk patients got identified was to ASK them if they had eye pain when they open their eyes in the morning.

Anyway, he said he has become increasingly aggressive in treating these cases early on because they always have such a rough ride in healing (as I think one or two people here can attest to). He'll actually do PTK immediately after surgery if necessary.

Originally Posted by Rebecca Petris

At a session on complications prevention & management at ESCRS the other day, John Kanellopoulos talked a bit about EBMD. - He laid a lot of stress on the importance of prevention, and, interestingly, said that the best way to make sure at-risk patients got identified was to ASK them if they had eye pain when they open their eyes in the morning.

Anyway, he said he has become increasingly aggressive in treating these cases early on because they always have such a rough ride in healing (as I think one or two people here can attest to). He'll actually do PTK immediately after surgery if necessary.

Sigh! I wish that the detection was that simple. Unfortunately, I have seen a number of patients with EBMD who categorically denied that they had any symptoms upon awakening. Definitely, nobody with symptoms of RCE should undergo LASIK.

However, it does speak to the need to do more rather than less in terms of case history elucidation.

DrG

[kurt]

From:

American Journal of Ophthalmology, September, Volume 130, pp 297-303

Sloughing of corneal epithelium and wound healing complications associated with laser in situ keratomileusis in patients with epithelial basement membrane dystrophy.

http://www.ncbi.nlm.nih.gov/entrez/q..._uids=11020408

...It is not recommended that laser in situ keratomileusis be performed in patients with classic, symptomatic epithelial basement membrane dystrophy. In patients who present with mild and asymptomatic epithelial basement membrane dystrophy, laser in situ keratomileusis should be performed with caution, or photorefractive keratectomy may be the preferred refractive procedure.

From:
LASEK (laser subepithelial keratomileusis).
Current Opinion in Ophthalmology. 13(4):261-263, August 2002.

Dastjerdi, Mohammad H. MD; Soong, H. Kaz MD

www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&li st_uids=12165712

...It [LASEK] may thus be safer for patients who are at an inherently higher risk of developing flap complications, such as those with small palpebral fissures, deep-set eyes, corneal basement membrane dystrophy, and extremely steep or flat corneas.

From:
Department of Opthalmology, The University of Texas Southwestern Medical Center at Dallas, Dallas , TX 75390-9057 , USA.

Effects of an educational seminar on rejection demographics in patients presenting for laser in situ keratomileusis.
MendelblattD, McCulley JP, Bowman RW, Verity S, Cavanagh HD.

www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&li st_uids=12695705

...The principal reasons for rejection were, in decreasing order of frequency: cataract, presbyopia, abnormal corneal curvature, insufficient corneal thickness, unstable refraction, large pupil, irregular astigmatism, anterior basement membrane dystrophy, previous corneal surgery, uncontrollable dry eye, and previously undiagnosed ocular malignancy....

CONCLUSIONS: Patients educated through group seminars or individually by trained technicians over the telephone still present for consideration for LASIK with unidentified ocular problems that make them poor surgical candidates. This occurs at a rate of 13%. The majority of the patients required a careful evaluation to uncover the abnormalities

Great post, Kurt.

DrG

[kurt]

Thus, the overall positive predictive value of the adhesion test [using a cellulose surgical sponge] was 59%

Corneal epithelial adhesion abnormalities associated with LASIK

Purpose

To assess the clinical characteristics, incidence, and pathologic correlation of corneal epithelial adhesion abnormalities encountered during LASIK.

Design
Prospective noncomparative interventional case series.

Participants

Five hundred consecutive eyes of 268 patients undergoing primary LASIK procedures by one surgeon utilizing the Moria LSK One microkeratome and VISX Star S-2 excimer laser.

Methods

Corneal epithelial adhesion was assessed immediately preoperatively using a cellulose surgical sponge (adhesion test), and the incidence, extent, and location of epithelial defects occurring during the microkeratome incision of the corneal flap were recorded. Epithelial specimens from 7 corneas requiring debridement of dysadhesive epithelium were examined by transmission electron microscopy.

Main outcome measures

The characteristics of the study population (age, gender, contact lens use, relevant ocular surface or systemic disease, refractive error, keratometry, pachymetry) and the microkeratome-related variables (head selection and vacuum level) were compared with the results of the preoperative epithelial adhesion test, the development of intraoperative epithelial effects (size and location), and the postoperative outcome.

Results

Epithelial defects were sustained by 51 corneas (10.2%), and among these, 31 (6.2%) were microdefects and 20 (4.0%) were macrodefects. The adhesion test was positive (indicative of compromised adhesion of epithelium to stroma) in 20 (64.5%) corneas with microdefects, but false negatives (epithelial defect despite negative adhesion test) occurred in 11 cases (35.4%). The adhesion test was positive in 16 (80%) of corneas having macrodefects, with 4 (20%) false negatives. Thus, the overall positive predictive value of the adhesion test was 59% , and the percentage of positive prediction was 92% (Bayes' theorem). Among all other outcome measures assessed, only corneal flap thickness seemed a potential risk factor, as 40 (78.4%) epithelial defects were associated with the creation of a 180- m-thick flap, whereas 10 (19.6%) were associated with a 160- m-thick flap and only 1 (2%) occurred with a 130- m flap. These trends were not, however, statistically significant (P = 0.15, Fisher exact test). Transmission electron microscopy of all epithelial debridement specimens disclosed consistent abnormality of the basement membrane adhesion complex, as thickened and multilaminated basement membrane remained adherent to the intact epithelial sheet.

Conclusions:

Corneal epithelial dysadhesion and defects occurring in the course of LASIK surgery may be associated with an intrinsic compromise of the basement membrane adhesion complex, as evidenced clinically by the adhesion test and demonstrated pathologically by duplicated basement membrane

[kurt]

I had an appointment yesterday with Dr. Michael Grimmett, M.D., F.A.C.S., F.A.C.P. He is both board certified in opthalmology, as a corneal specialist, and in internal medicine. He also works for the FDA reviewing among other things LASIK clinical results. He has looked at thousands of results. His practice is primarily corneal medicine and not LASIK. I don't even think he has a laser in his office.

Dr. Grimmett is a recognized expert in the diagnosis and treatment of EBMD. He has FDA approval to try an investigate medication for treating EBMD (I assume it is a drop of some sort).

Dr Grimmet told me that LASIK can cause EBMD. In my case, the EBMD is negligible. compared to the dry eye problem.

Very interesting.

Of course, we had long ago speculated about the compromise of epithelial adhesion post-LASIK on another website. Unfortunately, at that time there were no studies, and the doctors who were testing adhesion with a cellulose sponge were almost non-existent.

DrG