April 2020


Journal of Cataract & Refractive Surgery
In the journal: April2020

Duration of topical steroid application after photorefractive keratectomy with mitomycin-C: A systematic review and

Mojgan Pakbin, MSc, Mehdi Khabazkhoob, PhD, Akbar Fotouhi, MD, Mohammad Pakravan, MD, Ebrahim Jafarzadehpour, PhD, Mohamadreza Aghamirsalim, MD, Mohammad Amin Seyedian, MD, Hassan Hashemi, MD
Although corticosteroid use is common after PRK with mitomycin-C, studies are mixed on its results. This systematic review and meta-analysis culled through existing data from Jan. 1, 1980–Feb. 15, 2019, to analyze what the optimum corticosteroid dosage and duration might be after this procedure. The review found 1,262 studies, but after eliminating those that didn’t meet inclusion criteria, seven were included for the meta-analysis to evaluate the effect of corticosteroids on corneal haze score and spherical equivalent. The study authors concluded that steroids did result in lower haze scores, especially within the first 6 months postop. Use of steroids for a longer period of time, they continued, seems unnecessary in the patients with low to moderate myopia. The study authors noted that most studies published more than 2 decades ago did not include the use of mitomycin-C, which is often used now to reduce haze and refractive error regression after PRK. Haze was also more likely in earlier studies when earlier excimer lasers were used. The authors recommended a randomized clinical trial with newer treatment technologies and protocols to “clarify the optimum duration of postoperative steroid more precisely.”

Rho-associated kinase inhibitor decreases human corneal endothelial cell apoptosis: Ex-vivo study of corneal-scleral rims in Optisol-GS storage medium

Asaf Achiron, MD, Anna Feldman, PhD, Lily Karmona, MD, Liron Pe’er, MD, Haggay Avizemer, MD, Elisha Bartov, MD, Zvia Burgansky, MD, Mordechai Rosner, MD, Vicktoria Vishnevskia-Dai, MD
Rho-associated protein kinase (ROCK) inhibitors have been shown in previous studies to decrease apoptosis and encourage migration of cultured corneal endothelial cells. This study showed that use of a ROCK inhibitor can reduce endothelial cell loss in vitro and thus could be used to prevent or slow corneal endothelial cell loss in eye bank donor corneas. The researchers analyzed fragments of human donor corneas stored in a commercial storage medium for 1 week. Half of these samples had a ROCK inhibitor added to the medium. Endothelial cells were analyzed for early and late apoptosis, showing a reduced rate at both timeframes in the ROCK inhibitor group. They were also able to show fewer cells expressing ROCK in the cultures exposed to the ROCK inhibitor compared to controls. “This may be a promising new method for promoting future graft survival,” the authors concluded.

Corneal aberrations measured with the Oculus Pentacam HR: repeatability and reproducibility

Colm McAlinden, MD, Jim Schwiegerling, PhD, Jyoti Khadka, PhD, Konrad Pesudovs, PhD
Researchers at Flinders University in Australia wanted to determine how precise elevation and wavefront aberration measurements were with the Pentacam HR (Oculus). They selected 100 participants and a random eye was scanned twice with the Pentacam HR using the 25-picture, 50-picture, and cornea fine measurement modes. A second observer performed two scans with the 25-picture mode on the same random eye. Overall, investigators determined that the device was “highly precise” in terms of aberration outputs. They concluded that the most precise measurements are taken with the cornea fine measurement mode and wavefront aberrations. “One should be cognizant of posterior elevation aberration precision, particularly for lower radial order and higher azimuthal frequency terms,” the researchers wrote. “Accounting for tilt and misalignment of aberrations, all RMS and Zernike aberrations were extremely precise (repeatability and reproducibility limit less than 0.000001 μm).”

JCRS Journal of Cataract & Refractive Surgery In the journal: April2020 JCRS Journal of Cataract & Refractive Surgery In the journal: April2020
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