Research Digest

HCV and DED.

Because DED is frequently a complication of hepatitis C virus (HCV) infection, doctors in India, a country with a high incidence of HCV, undertook a study to determine whether a relationship existed between HCV and DED in patients without active HCV infection.

The authors collected tear fluid from 36 DED patients and 20 healthy controls, submitting the fluid to polymerase chain reaction to detect HCV RNA.

In addition, serum samples were collected from 15 of the 36 DED patients and were submitted to ELISA and other tests to detect anti-HCV immune activity.

Viral RNA was detected in 58.3% of the patients, and of the 15 patients who submitted serum samples, none had anti-HCV antibodies, which would have indicated subclinical hepatitis. However, 12 of 15 had elevated alkaline phosphatase, and all 15 had elevated alanine aminotransferase levels.

The authors report that their results indicate a direct relationship between DED and HCV, and they speculate that HCV might be a possible causative agent in DED, although considerably more research is necessary.

Finding AGREEment.

The Appraisal of Guidelines for Research and Evaluation (AGREE) II is an instrument designed to assess the rigor of clinical practice guidelines (CPGs).

Researchers collaborating between Florida and Rhode Island recently applied AGREE II to phacoemulsification CPGs. The CPGs chosen were those of the American Academy of Ophthalmology, the Canadian Ophthalmological Society (COS) and the Royal (United Kingdom) College of Ophthalmologists (RCO). These guidelines were assessed by four of the authors on six domains: scope and purpose; stakeholder involvement; rigor of development; clarity of presentation; applicability; and editorial independence.

The AAO guidelines scored strongly in editorial independence but weakly in the stakeholder involvement and applicability category. Comparably speaking, the RCO guidelines were weak in editorial independence, the COS guidelines were weak in applicability.

The authors made recommended on how guidelines could be improved, focusing on stakeholder involvement, applicability and editorial independence.

Danish phaco data.

Cataract surgeons in Copenhagen undertook a registry- and chart-based study of data from the Danish National Patient Registry to determine epidemiological characteristics of the data, as well as efficacy of phaco surgeries in Denmark.

Over the study years, spanning from 2004 to 2012, more than 400,000 phaco procedures were performed in nearly 250,000 patients. Most significantly, the authors found 62% greater mortality among patients undergoing phaco in public hospitals vs. those undergoing surgery in private facilities.

The authors noted that the increased mortality in the publicly treated cohort was due to worse baseline health status, rather than differences in the phaco procedures themselves.

They also found that both the mean age at the time of phaco and the interval between first and second eye surgeries decreased over time; both changes were greater in the patients treated in private hospitals and clinics.

Conversely, of the cases of endophthalmitis that emerged in the privately treated cohort, 46% were not reported in any registry, thereby limiting the quality of the data from the registries in general.

Post-DMEK complications.

IOP elevations and glaucoma are common following PK and DSEK, but what about after DMEK? To answer that question, surgeons in Germany undertook a retrospective analysis of data from a Berlin hospital.

Examining the data from patients who underwent DMEK between September 2011 and December 2012, the study team recorded data on IOP elevation and postoperative glaucoma, as well as pre-operative corneal disease and glaucoma, response to antiglaucoma treatment, graft failure, visual acuity and endothelial cell counts.

The 12-month incidence of IOP elevation ≥22 mg Hg or ≥10 mm Hg above baseline was 12.10%, and the rate of post-DMEK glaucoma was 2.7%. Both rates were lower than those for either PK or DSEK.

Steroids to prevent graft rejection remained the most common cause of IOP elevation. Only increased pre-operative IOP was a risk factor for IOP elevation. There were no cases of graft rejection.

The authors recommend that patients who undergo DMEK and who have pre-existing glaucoma or bullous keratopathy should receive regular IOP measurements; steroids should be tapered or replaced if such complications arise.

DMEK vs. DSAEK.

Patients with Fuchs’ dystrophy who underwent DMEK in one eye and DSAEK in the other were recently submitted to a retrospective chart review by doctors in Toronto.

The study team found 17 patients who had at least six months of follow-up data. They also collected information on BCVA and endothelial cell density. Finally, a subjective questionnaire was administered to the study cohort to assess patient satisfaction.

The eyes were comparable in BCVA pre-operatively. At six months following both procedures, BCVA was superior in the eyes submitted to DMEK. In addition, patient satisfaction was statistically significantly greater for eyes that underwent DMEK. Finally, endothelial cell density was also greater for the DMEK eyes, indicating fewer cells were lost.

While conceding the limits of a retrospective study, the authors suggest that DMEK is a superior procedure to DSAEK. They call for prospective and larger-cohort studies, particularly to determine longer-term endothelial cell density with both procedures.

OCT-guided keratectomy.

To determine long-term outcomes with optical coherence tomography–guided transepithelial phototherapeutic keratectomy (PTK) to treat anterior corneal scarring, cornea surgeons in Amarillo, Texas performed a chart review, recording BCVA and changes in OCT-measured data and changes in corneal photokeratoscopy indices.

Sixty-four eyes belonging to 60 patients who received keratectomy over a three-year period were studied. OCT was used pre-operatively to measure treatment depth for all.

Subsequently, combined myopic and transepithelial excimer hyperopic laser was applied.

At a mean follow-up of 41.0 weeks, BCVA improved by a mean of 0.43 logMAR. All of the corneal data measured showed significant improvements. The postoperative refractive error was a 0.91D mean difference from the planned outcome.

The authors feel OCT-guided transepithelial PTK will have a role to play in future treatment of corneal scarring. They call for randomized, controlled trials in the future.