36-Month Outcomes of Mechanical and Transepithelial PTK Epithelium Removal Techniques Prior to Accelerated CXL for Progressive Keratoconus.

PURPOSE: To compare the 36-month visual, refractive, and topographic results and the optical quality of the cornea between mechanical and transepithelial phototherapeutic keratectomy (PTK) epithelium removal techniques prior to the accelerated corneal cross-linking (CXL) procedure in patients with progressive keratoconus. METHODS: Keratoconic eyes that received either mechanical epithelium removal or transepithelial PTK epithelium removal prior to accelerated CXL with 36 months of follow-up were included. The uncorrected (UDVA) and corrected (CDVA) distance visual acuity, spherical equivalent (SE), manifest astigmatism, flat keratometry (K1), steep keratometry (K2), maximum keratometry (Kmax) readings, thinnest corneal thickness (TCT), topographic astigmatism, point spread function (PSF), and aberrometric parameters including root mean square higher order aberrations (RMS HOAs), vertical coma, and spherical aberration (SA) were assessed preoperatively and 12, 24, and 36 months postoperatively. RESULTS: One hundred ten eyes of 110 patients with keratoconus were included (mechanical epithelium removal group: 69 eyes, transepithelial PTK epithelium removal group: 41 eyes). After the CXL procedure, the mean UDVA, CDVA, manifest astigmatism, RMS HOAs, SA, vertical coma, and PSF improved significantly throughout the follow-up visits in both groups (P < .05 for all variables). The improvement in the mean UDVA, CDVA, manifest astigmatism, K1, K2, Kmax, RMS HOAs, SA, vertical coma, and PSF were significantly better in eyes that underwent transepithelial PTK epithelium removal when compared to eyes that underwent mechanical epithelium removal during the follow-up period (P < .05 for all variables). CONCLUSIONS: Transepithelial PTK-assisted accelerated CXL seems to be more efficient in improving the visual acuity and the optical quality while stabilizing the cornea compared to the accelerated CXL with mechanical epithelium removal in patients with progressive keratoconus. [J Refract Surg. 2022;38(3):191-200.].

Dynamics of keratoconus progression after a previous successful accelerated crosslinking treatment during and after pregnancy.

PURPOSE: To evaluate the effectiveness of previously applied successful accelerated corneal crosslinking (CXL) treatment in keratoconus stabilization during and after pregnancy. SETTING: Ankara Yildirim Beyazit University, Ataturk Training and Research Hospital, Turkey. DESIGN: Prospective clinical study. METHODS: Patients with stable keratoconus (after having an accelerated CXL procedure) who became pregnant were included. Uncorrected (UDVA) and corrected distance visual acuity (CDVA), manifest astigmatism (MA), keratometry (K)1, K2, Kmax, central corneal thickness (CCT), thinnest corneal thickness (TCT), and anterior (AE) and posterior elevation (PE) were recorded at baseline (before CXL), before pregnancy (the last visit after CXL), during pregnancy (third trimester), and after pregnancy (the last visit after pregnancy). RESULTS: 24 eyes of 19 patients were included. The mean time between CXL and conception was 12.4 ± 5.1 months. The mean postpartum follow-up period was 27.6 ± 13.3 months. The mean UDVA, CDVA, MA, and PE values did not show any statistically significant differences during and after pregnancy compared with the post-CXL values (P > .05). The mean Kmax flattened significantly after the CXL procedure (P = .011); however, it increased during pregnancy (P = .037, after CXL vs pregnancy) and then decreased back to the prepregnancy level after pregnancy (P = .035, pregnancy vs after pregnancy). The mean K1, K2, AE, CCT, and TCT remained stable during pregnancy and significantly decreased after pregnancy (P < .05). CONCLUSIONS: Keratoconus seems to progress during pregnancy in corneas that have previously received successful accelerated CXL treatment. However, this progress was mostly temporary, and generally, regression occurred after delivery.

Comparison of effects of mydriatic drops (1% cyclopentolate and 0.5% tropicamide) on anterior segment parameters.

Purpose: The purpose of this study is to investigate and compare the effects of cyclopentolate and tropicamide drops on anterior segment parameters in healthy individuals. Methods: Two hundred and fifty-eight eyes of 129 healthy volunteers were included in this randomized clinical study. Cyclopentolate 1% drop was applied to 75 (58%) participants (group 1) and tropicamide 0.5% drop was applied to 54 (42%) participants (group 2). Flat keratometry (K1), steep keratometry (K2), axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), white-to-white (WTW) distance, pupil diameter, total pupil offset and intraocular lens (IOL) power were measured before and after drops, using Lenstar 900 optical biometry. Results: The increase in CCT, ACD, pupil diameter, and pupil offset was significant in group 1 after the drop (P < 0.05), while the increase in ACD, pupil diameter, and pupil offset was significant in group 2 (P < 0.05). When the two groups were compared, there was no significant difference in K1, K2, CCT, ACD, WTW, pupil diameter, pupil offset, and IOL power (using Sanders-Retzlaff-Kraff T formula) changes after drops (P > 0.05), whereas the change in AL was significant (P = 0.01). Conclusion: The effects of cyclopentolate and tropicamide drops on anterior segment parameters were similar; they did not make significant changes in K1, K2, AL, WTW, and third-generation IOL power calculation. However, ACD values significantly changed after these drops; thus, measuring anterior segment parameters before mydriatic agents should be taken into account particularly for fourth-generation IOL formulas and phakic IOL implantation. The change in pupil offset, which can be important in excimer laser and multifocal IOL applications, was not clinically significant.

Evaluation of the correlation between quantitative measurement of the foveal avascular zone and retinal vessel density and outer retinal disruptions in diabetic patients

Background/aim: The aim of the current study was to evaluate the correlation between the integrity of the outer retinal layers on optical coherence tomography (OCT) and objective parameters of retinal microvascular perfusion on optical coherence tomography angiography (OCTA). Materials and methods: A total of 105 eyes of 54 diabetic patients were included in the study. Integrity of the outer retinal layers including the external limiting membrane (ELM), ellipsoid zone (EZ), and interdigitation zone (IZ) was assessed by spectral-domain optical coherence tomography. The foveal avascular zone (FAZ) area and vessel density (VD) measurements in the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in all the Early Treatment Diabetic Retinopathy Study (ETDRS) sectors were evaluated by OCTA. Associations between the quantitative measurement of the FAZ and retinal VD measurements and outer retinal disruptions were evaluated. Results: The FAZ area was correlated with outer retinal layer disruption both in the superficial plexus (r = 0.244, 0.228, 0.212, P = 0.013, 0.02, 0.031 for the ELM, EZ, and IZ, respectively) and the deep capillary plexus (r = 0.298, 0.234, 0.197, P = 0.002, 0.019, 0.048 for the ELM, EZ, and IZ, respectively). A significant relationship was also found between the VD measurements in the SCP and DCP in ETDRS sectors and the outer retinal layers disruption. Conclusion: The results of the current study show a significant relationship between the quantitative OCTA parameters and the integrity of the outer retinal layers. This finding reveals a correlation between retinal capillary nonperfusion and outer retinal disruption in eyes with diabetic retinopathy.