Visual Outcomes and Aberrometric Changes With Topography-Guided Photorefractive Keratectomy Treatment of Irregular Astigmatism After Penetrating Keratoplasty.

PURPOSE: To evaluate the visual acuity and keratometric and aberrometric changes in patients with corneal transplants (PKP), who underwent topography-guided photorefractive keratectomy (TG-PRK) with mitomycin C (MMC). METHODS: In this case study, 15 patients with spherical equivalents ranging from -11.00 to -0.25 diopters (D) who underwent penetrating corneal transplantation and had irregular astigmatism ranging from -7.5 to -2.0 D underwent TG-PRK with MMC. Corneal topography and wavefront of all patients were measured preoperatively and 12 months postoperatively. RESULTS: Twelve months after TG-PRK with MMC, 46% of eyes achieved a best spectacle-corrected visual acuity (BSCVA) of 20/20 compared with 1 eye preoperatively (P = 0.0221, χ test). The BSCVA did not improve in 1 patient and increased by 1 line or more in all others. Astigmatism decreased significantly (P = 0.003) from 5.10 ± 0.4 D to 3.37 ± 0.06 D, the corneal best-fit sphere increased and keratometry measurements flattened significantly (P = 0.0001 for both comparisons), and the corneal total root mean square aberrations and trefoil decreased significantly (P = 0.0077 and P = 0.0054, respectively) from 9.11 ± 2.56 µm to 7.58 ± 3.15 µm and 2.00 ± 1.2 to 1.38 ± 0.27 µm, respectively, as measured by wavefront aberrometry. CONCLUSIONS: Twelve months postoperatively, the BSCVA improved significantly, the lines of vision increased, and astigmatism, corneal best-fit sphere, mean keratometry, corneal thickness, corneal root mean square total, and corneal spherical aberrations decreased. TG-PRK with MMC is a good alternative for correcting post-PKP cases with irregular astigmatism with elevated higher-order aberrations.

Effect of a light-emitting timer device on the blink rate of non-dry eye individuals and dry eye patients.

PURPOSE: To evaluate blink rate effects by a novel light-emitting diode (LED) timer device (PISC) on non-dry eye (DE) subjects and DE patients during a reading task on liquid crystal display (LCD) screens, in different environmental conditions. METHODS: This was a case-control study that included 15 DE patients and 15 non-DE subjects as controls. Participants had their blink rates measured while they read an electronic format text. These tasks were performed in four different conditions: with and without a LED timer device in two visits, and with and without air conditioning. All participants completed the Ocular Surface Disease Index and were examined by best spectacle-corrected visual acuity exam, biomicroscopy, Schirmer test 1, fluorescein staining and break-up time and lissamine green staining (Oxford scale grading). RESULTS: Outcomes between reading tasks conditions were compared independently for each group and blink rate frequency was higher in tasks with LED timer device, with and without air conditioning, for the DE group (p<0.0001), and with air conditioning for the control group (p<0.05). CONCLUSIONS: An LED timer device increased blink frequency for DE and control groups. Further studies need to be carried out in order to evaluate long-term effects of this new device, as well as its assessment with different reading scenarios.