Eyeworld Daily News

24 | EYEWORLD DAILY NEWS | APRIL 23, 2022 ASCRS ANNUAL MEETING DAILY NEWS PhD, discussed what really matters when requesting donor tissue. He first discussed factors that surgeons care about when asking for donor tissue, noting that he asked his local eye bank about some of the factors. Minimum endothelial cell density, age, death to preservation, death to surgery, and medical rule-outs were some of the factors. The eye bank said that 88% of active domestic surgeons have at least one tissue parameter. Later in his presentation, Dr. Chamberlain discussed myths relating to donor tissue. The first was that younger grafts are better for PKP and DSAEK. Donor age is not an important factor in most penetrating keratoplasties for endothe- lial disease, he said, noting data from the Cornea Donor Study. Five-year graft survivals for corneal transplants at moderate risk for failure are similar using corneal tissue from donors older or equal to 66 years compared to do- nors younger than 66. The second myth was that cell counts matter for PKP and DSAEK. The Cornea Donor Study, Dr. Chamberlain said, showed that preoperative endo- thelial cell density is unrelated to graft at-risk family members of known ker- atoconus patients, and those with high association with keratoconus (Down syndrome, Marfan syndrome). Dr. Garg shared a few cases where he used genetic testing. The first was a 32-year-old female who had been referred after LASIK evaluation, with no recent refractive changes, and she denied eye rubbing. The patient also denied family history of keratoconus and was motivated to have LASIK. The genetic test showed moderate to high risk, so Dr. Garg decided not to use laser and to follow up at 6 months with the patient. He also said he would potentially consider crosslinking for this patient. His second case was a 31-year-old female who had been seen elsewhere for a LASIK evaluation, and the doctor recommended PRK. The patient had no recent refractive changes and denied eye rubbing. When looking at the maps, Dr. Garg noted that nothing looked abnormal. The results of the genetic test were not particularly help- ful in this case; it noted a moderate keratoconus risk. Lastly, he shared the case of a 27-year-old prior contact lens user with stable refraction. The maps showed a bit of thinning but a good residual stro- mal bed. Dr. Garg is currently seeing this patient and has not yet performed the genetic test, but he questioned panelists if their opinion of this patient would change knowing that the pa- tient's father had keratoconus. In conclusion, Dr. Garg said that genetic testing for keratoconus is new and holds a lot of promise. It allows risk stratification, aids with clinical quandaries, and hopefully helps with early diagnosis and screening. Dr. Garg stressed that the test results are not binary, but rather they are a spectrum. He said to expect evolving guidelines of how best to incorporate genetic testing for laser vision. The second session of Cornea Day focused on anterior/posterior lamellar surgery. Winston Chamberlain, MD, T he first session of the 2022 Cornea Day program covered updates in the management of keratoconus and corneal ecta- sia. During the session, Sumit "Sam" Garg, MD, presented on genetics, specifically genetic testing and appli- cations in keratoconus. We know that keratoconus is a bilateral progressive corneal ectasia resulting in irregular astigmatism and loss of visual func- tion, with onset in teenage years, Dr. Garg said. Diagnosis is generally made by a corneal specialist, by looking at patient history and symptoms, as well as clinical signs, corneal topography/ tomography, and pachymetry mapping. Now, genetic testing is beginning to be used for keratoconus. Keratoconus prevalence is indi- vidual, and there is not a "one size fits all" approach. Dr. Garg mentioned that optical coherence tomography (OCT), wavefront aberrometry, and corneal biomechanics tests are newer exams that may be used for diagnosing kera- toconus. He then spoke about the use of genetic testing for diagnosis of kerato- conus. The AvaGen (Avellino) 75-gene panel plus more than 2,300 variants identifies the risk of most keratoconus and 70-variant gene TGFBI corneal dystrophy patients. The test has been validated in more than 1,100 patient DNA samples in the U.S.; patient samples are displayed with a risk score reference bar, from 0 to 100, using a green-yellow-red scale. Each patient sample receives its own numeric risk score and determination of low to high risk. Who should you consider getting a genetic test on? Dr. Garg mentioned several groups of patients who might benefit: those with topography/to- mography anomalies (astigmatism pattern concerns, pachymetry, posterior corneal bowing), those with unstable refractions (differentiating early my- opia from keratoconus), where there are concerns of post-LASIK ectasia, those with ocular allergy/eye rubbing, Cornea Day covers topics in keratoconus, corneal ectasia, lamellar surgery Dr. Garg presents on genetic testing for keratoconus during Cornea Day.

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