The search for a substitute for the natural cornea dates back more than 200 years. Although several devices have been developed and trialled, very few have had successful long-term results and continue in regular clinical use. Keratoprosthesis (KPro) surgery is complex and should be performed in centres with an experienced multidisciplinary team. Currently available KPro devices range from the totally synthetic, such as the Boston KPro, to the totally biological tissue-engineered artificial cornea. The osteo-odonto keratoprothesis combines a synthetic optic with a biological haptic. All keratoprostheses have significant limitations, although visual improvement is possible with each of the devices in clinical use today. This review discusses these devices with emphasis on their indications, surgical techniques and results, before briefly exploring emerging devices and innovative approaches for the future.

No abstract

Background: Disorganization of the retinal inner layers (DRIL) on optical coherence tomography (OCT) is thought to represent retinal capillary nonperfusion (CNP) in eyes with diabetic retinopathy. This study was designed to evaluate the ability of DRIL to accurately predict CNP.

Retinal thickness measurements in subjects with DME obtained using Spectralis OCT are considerably less variable than has been reported with other devices. Changes in central subfield thickness >8 μm can be considered more indicative of true clinical change rather than measurement variability. This finding informs clinical practice and clinical trial design.

The PVS may underestimate children's refractive error.

Purpose of review: This review will discuss how recent advances with induced pluripotent stem (iPS) cells have brought the science of stem cell biology much closer to clinical application for patients with retinal degeneration. Recent findings:The ability to generate embryonic stem (ES) cells by reprogramming DNA taken from adult cells was demonstrated by the cloning of Dolly the sheep by somatic cell nuclear transfer over ten years ago. Recently it has been shown that adult cells can be reprogrammed directly, without the need for a surrogate oocyte through the generation of induced pluripotent stem (iPS) cells. The method of reprogramming has since been optimised to avoid the use of retroviruses, making the process considerably safer. Last year human iPS cells were isolated from an 80 year old patient with neurodegenerative disease and differentiated into neurons in vitro.Summary: For stem cell therapies, the retina has the optimal combination of ease of surgical access, combined with an ability to observe transplanted cells directly through the clear ocular media. The question now is which retinal diseases are most appropriate targets for clinical trials using iPS cell approaches.

Aims: To document loss of central field in patients with scars from toxoplasmic retinochoroiditis close to the disc after resolution of disease. Methods: Patients with a clinical diagnosis of toxoplasmic retinochoroiditis were enrolled from four centres. Automated central visual field testing was performed when their disease had settled and retinal photographs of the lesions were taken. The type of central field defect (whether absolute or relative) and whether it broke out to the periphery were correlated with the size of the retinochoroidal scar and its proximity to the optic nerve head. Results: 69 eyes were enrolled; 16 (26%) were discarded because of poor field performance. Of the 53 remaining eyes, 31 showed absolute defects and 20 relative defects. Scars within one disc diameter of the disc were more likely to be associated with absolute defects breaking out to the periphery. Conclusion: The scarring induced by toxoplasmic retinochoroiditis is associated with considerable field loss when it occurs close to the optic nerve head. Current treatment is unlikely to ameliorate this situation. The degree of visual field loss should be an outcome measure for future trials of the efficacy of treatment trials for the disease.

IMPORTANCE Panretinal photocoagulation (PRP) for proliferative diabetic retinopathy (PDR) may lead to peripheral field loss that prevents driving. Anti-vascular endothelial growth factor agents are proposed as treatments for PDR that spare peripheral vision. If multispot lasers cause less visual field loss, continuing to perform PRP may be justified. OBJECTIVE To assess the effect of bilateral multispot laser PRP on retinal sensitivity and driving visual fields in PDR. DESIGN, SETTING, AND PARTICIPANTS This prospective nonrandomized interventional cohort analysis performed at a tertiary referral center included 43 laser-naive patients with PDR that required bilateral PRP. Participants were recruited from June 27, 2012, to October 14, 2013. At baseline and 6-month follow-up, patients underwent detailed static and kinetic perimetry, microperimetry, optical coherence tomography, wide-field color fundus photography, and fluorescein angiography. Quantitative change in retinal sensitivity was assessed by comparing the mean global retinal sensitivity before and after laser treatment and by comparing the modeled hill of vision by deriving a volumetric measure. Final follow-up was completed on May 21, 2014. INTERVENTIONS Multispot laser treatment was applied using standard parameters, until neovascularization regressed or complete retinal coverage was achieved. MAIN OUTCOMES AND MEASURES Participants who passed the Esterman binocular visual field test for driving in the United Kingdom (at least 120°horizontal field with no significant defects within the central 20°) and full-field and macular retinal sensitivity. RESULTS Of the 43 patients (17 men; 26 women; mean [SD] age, 46.6 [13.3] years), 38 (88%) completed the study. Before treatment, 41 of 43 patients (95%) passed the Esterman visual field test for driving; after completion of laser treatment, 35 of 38 patients (92%) passed. The mean (SD) change in retinal sensitivity on static perimetry was −1.4 (3.7) (95% CI, −2.7 to −0.1) dB OD and −2.4 (2.9) (95% CI, −3.4 to −1.4) dB OS. Mean (SD) 4°macular sensitivity decreased by 3.0 (5.2) dB OD and 2.6 (5.4) dB OS. CONCLUSIONS AND RELEVANCE This prospective study investigating the effects of multispot laser PRP on retinal sensitivity demonstrates a high likelihood of retaining eligibility to drive based on adequate visual field. A mild loss of retinal sensitivity was detected at 6 months after completion of laser treatment. Further change to visual fields may have occurred with longer follow-up. This study provides information that might be used to counsel patients requiring PRP and informs the debate regarding the role of anti-vascular endothelial growth factor therapy in patients with PDR who might otherwise receive laser treatment.