Short-term effect of topical brimonidine tartrate on intrastromal corneal pressure in rabbits

Incidence, Risk, and Visual Outcomes after Repositioning of Acute Non-Traumatic Flap Dislocations Following Femtosecond-Assisted LASIK

Although the use of femtosecond lasers instead of mechanical devices has decreased the incidence of flap complications following laser-assisted in situ keratomileusis (LASIK), dislocations and striae still occur. Flap repositioning is an effective intervention to improve visual outcomes after acute flap complications in both microkeratome-assisted and femtosecond-assisted LASIK. This retrospective case series included patients undergoing flap repositioning secondary to acute flap dislocation and/or visually significant striae within the first two weeks following femtosecond LASIK (FS-LASIK) from 2015 to 2020 at a single institution. Preoperative, intraoperative, and postoperative de-identified data were analyzed for incidence, risk factors, and visual acuity outcomes. The incidence of flap repositioning was 0.35% in 21,536 eyes (n = 70). Indications for repositioning included acute flap dislocation (35.7%) and visually significant striae (64.3%). High myopia (OR = 3.04, p = 0.001) and patient age over 50 years (OR = 3.69, p = 0.001) were the strongest risk factors for these complications. Prior to flap repositioning, uncorrected distance visual acuity (UDVA) of 20/20 or better and 20/40 or better occurred in 19% and 57% of eyes, respectively. After repositioning, a final UDVA of 20/20 or better and 20/40 or better occurred in 78% and 98% of eyes, respectively. After repositioning, one line of UDVA was lost in two eyes (2.8%) and two lines were lost in one eye (1.4%). Risk factors for acute flap dislocation included high myopia and age over 50 years. Flap repositioning was effective in salvaging visual outcomes.

Non adherence of flap following microkeratome-assisted laser-assisted in situ keratomileusis: A case report and review of literature

A 28-year-old male underwent microkeratome assisted Laser-assisted in situ keratomileusis (LASIK) for, myopia. On postoperative day 1, patient had a large epithelial defect in OD. The corneal epithelial defect healed within 72 hours, but sub-optimal vision persisted. The patient was referred for further management to us. On evaluation, patient had non-healing of flap margin at 5 o'clock. Fluoroscein stain revealed no corneal epithelial defect, but a large pool of dye beneath the LASIK flap. A clinical diagnosis of non-adherence of LASIK flap was considered. Application of bandage contact lens was done. LASIK flap completely healed in 1 week. Possible etiologies are discussed and literature is reviewed.

Effect of Acute Increases in Intraocular Pressure on Corneal Pachymetry in Rabbit Eyes Treated with Timolol Maleate

Objective:

To evaluate in an in vivo rabbit model, the effect of topical timolol maleate therapy on the central corneal thickness response to acute intraocular pressure increases.

Method:

In this prospective and interventional controlled study, the central corneal thickness and intraocular pressure were measured in vivo in 12 rabbit eyes treated with topical timolol maleate for 1 month and in 12 controls at baseline, and after the intraocular pressure (measured by direct cannulation of the anterior chamber) was increased to 15 and 30 mmHg using a forced saline infusion into the anterior chamber.

Results:

There were no significant differences in the basal central corneal thickness values (control group, 373.2±12.9 µm; study group, 377.5±19.2 µm, p=0.5) or the central corneal thickness values when the intraocular pressure was increased to 15 mmHg (control group, 335.2±14.3 µm; study group, 330.0±32.1 µm, p=0.6) and to 30 mmHg (study group, 318.8±25.3 µm; control group, 329.8±21.0 µm, p=0.3).

Conclusion:

Rabbit corneas treated with topical timolol maleate for 1 month did not show a strain response to acute intraocular pressure increases that differed from control eyes. This is in contrast to a previous finding in which rabbit eyes treated with prostaglandin analogues had a greater decrease in central corneal thickness in response to a sudden intraocular pressure increase compared with untreated corneas.

The increasing importance of translational vision research in refractive surgery

Addressing these business and financial components of research, we believe that including a section on translational vision research especially for refractive surgery will be a welcome addition to the readership of the Journal. Although the section "Translational Science" is new, the Journal has published a number of articles in past years that would have been ideal candidates for such a section. The inaugural Translational Science article in this month's issue is fron Santhiago and colleagues on short-term cell death and inflammation after intracorneal inlay implantation in rabbits. Although not all scientists are in agreement with the promotion of this term, the Journal aims to provide different outlooks and modern usage of translational research in this way to advance the field of refractive surgery.