Thick biological tissues give rise to not only the multiple scattering of incoming light waves, but also the aberrations of remaining signal waves. The challenge for existing optical microscopy methods to overcome both problems simultaneously has limited sub-micron spatial resolution imaging to shallow depths. Here we present an optical coherence imaging method that can identify aberrations of waves incident to and reflected from the samples separately, and eliminate such aberrations even in the presence of multiple light scattering. The proposed method records the time-gated complex-field maps of backscattered waves over various illumination channels, and performs a closed-loop optimization of signal waves for both forward and phase-conjugation processes. We demonstrated the enhancement of the Strehl ratio by more than 500 times, an order of magnitude or more improvement over conventional adaptive optics, and achieved a spatial resolution of 600 nm up to an imaging depth of seven scattering mean free paths.

Purpose: To examine the effects of nerve growth factor (NGF) on apoptosis and inflammation in the diabetic cornea. Methods: To investigate the effects of NGF on glucose-induced apoptosis, we stained human corneal epithelial cells (HCECs) for annexin-V and propidium iodide (PI), and measured expression of cleaved caspase-3 and the Bcl-2–associated X protein (BAX). Moreover, to examine the effects of NGF on inflammation, we quantified the expression of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) using multiplex cytokine analysis, and analyzed nuclear factor-κB (NF-κB) activation and NF-κ-B inhibitor α (IκBα) degradation using Western blot analysis. To investigate the effects in vivo, we induced diabetes in male Sprague–Dawley rats using streptozotocin. The rats were divided into three groups: control, diabetic control, and diabetic NGF; topical NGF was applied three times daily for 3 weeks. We used the TUNEL assay to detect apoptosis in corneal tissue, and immunohistochemistry to identify cleaved caspase-3 and IL-1β. Results: In HCECs, high glucose concentration (≥25 mM) led to reactive oxygen species (ROS) generation, apoptosis, and the release of inflammatory cytokines. Nerve growth factor markedly reduced ROS activation, annexin-PI–positive cells, and levels of cleaved caspase-3, BAX, IL-1β, and TNF-α. In the diabetic rat cornea, apoptosis and inflammation were enhanced, as were levels of cleaved caspase-3 and IL-1β. These responses were markedly reduced by NGF. Conclusions: Apoptosis and inflammation are enhanced in the diabetic cornea; NGF attenuates these responses—both in vivo and in vitro. Therefore, NGF therapy may represent a novel approach for the management of diabetic keratopathy.

Purpose: To evaluate the effect of diquafosol on corneal epithelium in a dry eye model using Transwell culture and a scopolamine-induced dry eye rat model. Methods: Desiccation stress induced in an in vitro dry eye model using human corneal epithelial cells was used, and the cells were incubated with or without diquafosol media diluted at 1:100. Reactive oxygen species (ROS) generation was measured using 2′,7′-dichlorofluorescein diacetate (DCFH-DA). Apoptosis was analyzed, and levels of phosphorylated Erk1/2, phosphorylated p90RSK, phosphorylated Akt, IκB-α, and NF-κB-p65 were determined. Levels of IL-1β, TNF-α, IL-6, IL-8, and GM-CSF were quantified. To investigate the in vivo effects of diquafosol, we induced dry eye in Wistar rats using scopolamine hydrobromide. The rats were divided into three groups: control, dry eye, and dry eye diquafosol; topical DIQUAS was applied four times daily for 28 days. We used immunohistochemistry to detect the levels of phosphorylated Erk1/2, phosphorylated p90RSK, and IL-1β, and used the TUNEL assay in corneal tissue. Results: The distribution of highly fluorescent dichlorofluorescein and the proportion of annexin V- and PI-positive cells decreased in the diquafosol medium. Diquafosol increased the levels of phospho-Erk1/2, phospho-90RSK, phospho-Akt, and IκB-α, whereas it significantly decreased the levels of NF-κB-p65, IL-1β, and TNF-α. In vivo, apoptosis was enhanced in dry eye group. This response was markedly reduced and the level of phosphorylated p90RSK and phosphorylated ERK1/2 were upregulated and IL-1β was downregulated by DIQUAS. Conclusions: Diquafosol treatment reduced intracellular ROS levels, apoptosis, and inflammation, all of which were increased in the dry eye model through desiccation.

Purpose: We evaluated the effects of N-acetylcysteine (NAC), which is known to inhibit reactive oxygen species (ROS)–dependent apoptosis, on high glucose–induced ROS, apoptosis, inflammation, and delayed-wounding closure in primary cultured human conjunctival epithelial cells (pHCECs), and the regulatory effects of cleaved caspase-3, BAX, nuclear factor κB (NF-κB), IL-6, and TNF-α on these processes. Methods: High glucose–induced ROS generation was measured using 2′,7′-dichlorofluorescein diacetate (DCFH-DA). The effects of NAC on high glucose–induced apoptosis were investigated in pHCECs using Annexin-V and PI staining, and cleaved caspase-3 and BAX expression levels using immunoblotting. To evaluate the inflammatory response, IL-6 and TNF-α expression levels were quantified by multiplex cytokine analysis, and NF-κB activation and IkB-α degradation were assessed by Western blot analysis. The effects of NAC on high glucose–delayed conjunctival epithelial wound healing were assessed by a scratch-induced directional wounding assay. Results: Compared to the untreated control and normal glucose (5 mM), high glucose at 25 mM stimulated ROS generation, apoptosis, and release of inflammatory cytokines, and delayed wound healing in pHCECs. The addition of NAC markedly reduced the high glucose–induced ROS activation, Annexin-PI–positive cells, and levels of cleaved caspase-3, BAX, IL-6, and TNF-α. N-acetylcysteine also prevented high glucose–delayed wound healing. Conclusions: High glucose levels promote apoptosis by affecting mitochondria-dependent caspase activity through elevation of ROS production, a process that can be reversed by the antioxidant NAC. These findings demonstrate that NAC has a beneficial effect on conjunctival epithelial cell wound healing, antiapoptosis, and anti-inflammation in the conjunctival epithelial cell.

Purpose. To quantify whole lens and nuclear lens densities using anterior-segment optical coherence tomography (OCT) with a liquid optics interface and evaluate their correlation with Lens Opacities Classification System III (LOCS III) lens grading and corrected distance visual acuity (BCVA).Methods. OCT images of the whole lens and lens nucleus of eyes with age-related nuclear cataract were analyzed using ImageJ software. The lens grade and nuclear density were represented in pixel intensity units (PIU) and correlations between PIU, BCVA, and LOCS III were assessed.Results. Forty-seven eyes were analyzed. The mean whole lens and lens nuclear densities were 26.99 ± 5.23 and 19.43 ± 6.15 PIU, respectively. A positive linear correlation was observed between lens opacities (R2= 0.187,p<0.01) and nuclear density (R2= 0.316,p<0.01) obtained from OCT images and LOCS III. Preoperative BCVA and LOCS III were also positively correlated (R2= 0.454,p<0.01).Conclusions. Whole lens and lens nuclear densities obtained from OCT correlated with LOCS III. Nuclear density showed a higher positive correlation with LOCS III than whole lens density. OCT with a liquid optics interface is a potential quantitative method for lens grading and can aid in monitoring and managing age-related cataracts.

To investigate changes in corneal higher-order aberrations (HOAs) associated with the incision location in cataract surgery. Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Observational case series. Eyes were divided into 3 groups according to the different axes of incision location: superior, temporal, and nasal. Preoperative and 1-month postoperative corneal coma, trefoil, and spherical aberrations were compared. The study evaluated 119 eyes that had uneventful cataract surgery with a 2.2 mm limbal incision. The superior incision group showed significant changes in the vertical coma (amount of change: -0.119 μm ± 0.153 [SD]; P < .001) and vertical trefoil (amount of change: 0.185 ± 0.260 μm, P = .001). The nasal incision group showed a significant change in oblique trefoil (amount of change: 0.176 ± 0.207 μm; P < .001). The temporal incision group did not show significant changes in HOAs. The superior incision in 2.2 mm phacoemulsification cataract surgery caused a change in the corneal vertical coma in a negative direction. Corneal trefoil changes were dependent on the incision location. No author has a financial or proprietary interest in any material or method mentioned.