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Purpose: To review the published literature on the visual acuity results and complications of different surgical techniques for intraocular lens (IOL) implantation in the absence of zonular support.Methods: Peer-reviewed literature searches were conducted last in PubMed and the Cochrane Library in July 2019. The searches yielded 734 citations of articles published in English. The panel reviewed the abstracts of these mostly retrospective case series studies, and 45 were determined to be relevant to the assessment objectives. Three articles were rated as level II evidence, and 42 articles were rated as level III evidence.Results: Eight different types of IOL fixation techniques with at least 6-month follow-up were evaluated: anterior chamber IOL (ACIOL), iris-claw IOL, retropupillary iris-claw IOL, 10-0 polypropylene iris-sutured posterior chamber IOL (PCIOL), 10-0 polypropylene scleral-sutured PCIOL, 8-0 polypropylene scleral-sutured PCIOL, CV-8 polytetrafluoroethylene, and intrascleral haptic fixation (ISHF). Eight articles reported data comparing 2 techniques. The 45 studies had insufficient statistical power to compare the techniques conclusively. A qualitative analysis of similar types showed that trends in visual acuity outcomes were not inferior to those of ACIOL implantation, but the severity of preoperative pathologic features was not controlled for. Compared with ACIOL, complications of cystoid macular edema were higher in 10-0 polypropylene iris-sutured PCIOL and 8-0 polypropylene scleral-sutured PCIOL. Noneanterior chamber IOL techniques were less likely to report chronic uveitis. Chronic glaucoma was highest in the 8-0 polypropylene scleral-sutured PCIOL group. Although retinal detachment was infrequent overall, it was twice as common in both iris-and scleral-sutured PCIOLs (except CV-8 polytetrafluoroethylene suture) compared with nonsutured methods: ACIOL, iris-clipped IOL, and ISHF PCIOL.Conclusions: The evidence reviewed shows no superiority of any single IOL implantation technique in the absence of zonular support. The various techniques seem to have equivalent visual acuity outcomes and safety profiles. Each technique has its own profile of inherent risk of postoperative complications. Surgeons must educate patients on the importance of close, long-term follow-up as a result of the uncertain nature of these techniques. Large prospective studies are needed to confirm the long-term complication profiles of these various IOL implantation techniques.

PurposeBoston Terriers (BTs) have a greater prevalence of corneal endothelial dystrophy (CED), in comparison to other canine breeds. Similar to Fuchs' endothelial corneal dystrophy (FECD), this condition is characterized by endothelial cell degeneration with secondary corneal edema. This study assessed corneal morphology using in vivo confocal microscopy (IVCM) and Fourier-domain optical coherence tomography (FD-OCT) in BTs with and without CED.MethodsThe corneas of 16 BTs with CED and 15 unaffected, age-matched BTs underwent clinical evaluation and were imaged using IVCM and FD-OCT. A two-sample t-test or Mann-Whitney rank sum test were used to statistically compare parameters between groups. Data are presented as mean ± SD or median (range).ResultsMean age did not significantly differ between affected and unaffected dogs at 10.0 ± 2.0 and 10.6 ± 2.4 years, respectively (P = 0.437). Females (69%) were overrepresented among the CED-affected dogs. In CED patients, IVCM demonstrated endothelial polymegathism and pleomorphism. Corneal endothelial density was significantly less (P < 0.001) in dogs with CED (1026 ± 260 cells/mm2) versus age-matched controls (2297 ± 372 cells/mm2). Fourier-domain OCT demonstrated a significant increase (P < 0.01) in central corneal and endothelium-Descemet's complex thickness in dogs with CED versus age-matched controls at 1019 (485–1550) or 536 (464–650) μm and 32 (22–56) or 25 (15–34) μm, respectively.ConclusionsCorneal endothelial dystrophy in BTs is a bilateral, adult-onset condition that shares many similarities with FECD. Thus, CED could serve as a spontaneous disease model to study the pathogenesis of and develop novel treatments for FECD.

Retinal ganglion cells (RGCs) drive diverse, light-evoked behaviors that range from conscious visual perception to subconscious, non–image-forming behaviors. It is thought that RGCs primarily drive these functions through the release of the excitatory neurotransmitter glutamate. We identified a subset of melanopsin-expressing intrinsically photosensitive RGCs (ipRGCs) in mice that release the inhibitory neurotransmitter γ-aminobutyric acid (GABA) at non–image-forming brain targets. GABA release from ipRGCs dampened the sensitivity of both the pupillary light reflex and circadian photoentrainment, thereby shifting the dynamic range of these behaviors to higher light levels. Our results identify an inhibitory RGC population in the retina and provide a circuit-level mechanism that contributes to the relative insensitivity of non–image-forming behaviors at low light levels.

In addition to its well-known role in pattern vision, light influences a wide range of non-image forming, subconscious visual behaviors including circadian photoentrainment, sleep, mood, learning, and the pupillary light reflex. Each of these behaviors is thought to require input from the M1 subtype of melanopsin-expressing, intrinsically photosensitive retinal ganglion cell (ipRGC). Recent work has demonstrated that the M1 subtype of ipRGC can be further subdivided based on expression of the transcription factor Brn3b. Brn3b-positive M1 ipRGCs project to the olivary pretectal nucleus and are necessary for the pupillary light reflex, while Brn3b-negative M1 ipRGCs project to the suprachiasmatic nucleus (SCN) and are sufficient for circadian photoentrainment. However, beyond the circadian and pupil systems, little is known about the projection patterns of M1 ipRGC subtypes. Here we show that Brn3b-positive M1 ipRGCs comprise the majority of sparse M1 ipRGC inputs to the thalamus, midbrain, and hypothalamus. Our data demonstrate that very few brain targets receive convergent input from both M1 ipRGC subpopulations, suggesting that each subpopulation drives a specific subset of light-driven behaviors.