Comparative evaluation of four Descemet membrane endothelial keratoplasty graft preparation techniques.

OBJECTIVE: To compare subjective and objective outcomes of 4 different Descemet membrane endothelial keratoplasty (DMEK) peeling techniques performed by novice surgeons at different stages in their surgical career. DESIGN: An ex vivo prospective study. METHODS: In the first round, 2 DMEK peeling techniques were pitched against each other: the peripheral scoring and Sinskey dissection technique with the peripheral scoring and microhoe dissection and the peripheral blunt microhoe dissection against the scleral spurectomy and microhoe dissection. Three surgeons with different operative experience performed the peeling. Outcome measures included graft peeling time, surgeon's peeling difficulty grading (on a scale of 1-10, 1 being the easiest and 10 the hardest), number of radial and circumferential tears before and after trephination, and tissue loss. The 2 techniques that performed the best from the first round proceeded to the final round to identify the best overall technique. RESULTS: In total, 90 tissues (45 pairs) were peeled by 3 surgeons. Following the first-round results, the peripheral scoring and Sinskey dissection and peripheral blunt microhoe dissection proceeded to the final round. There were no significant differences between the groups in terms of peeling times, subjective feeling of difficulty, post-trephination tears, and peeling success rates (P > 0.05 for all). However, the peripheral scoring and Sinskey dissection technique had significantly fewer pretrephination radial tears (1.3 ± 1.3 vs 6.1 ± 5.2, P = 0.007) and circumferential tears (0.6 ± 0.9 vs 1.8 ± 2.1, P = 0.02). CONCLUSIONS: This study demonstrates that the learning curve can be overcome quickly with appropriate DMEK peeling techniques. The peripheral scoring and Sinskey dissection peeling technique allows efficient peeling with fewer related tears.

Delivering eye care to homeless and marginally housed populations during the COVID-19 pandemic: a pilot study.

OBJECTIVE: Homeless and marginally housed populations experience a higher prevalence of visual impairment relative to the general population. The aim of this pilot study is to present a novel model for conducting ocular screening clinics for homeless individuals during a pandemic and to describe the status of ocular health in this population during this time. METHODS: In this cross-sectional study, 3 outdoor tent-based ocular screening clinics were held in a park in Toronto. Most participants were recruited from local shelters, but additional spots were allocated for homeless individuals on a drop-in basis. Prior to enrolment, each participant underwent COVID-19 screening via a questionnaire and temperature measurement. Those who screened negative received a comprehensive eye examination, including vision testing, dilated fundus examination, and autorefraction. RESULTS: Eleven individuals completed all assessments. The mean age of participants was 54.5 years, and 11 of the participants were male. Visual impairment was found in 5 individuals. Refractive error via pinhole testing was found in 1 patient. Ocular pathology in this sample was found in 4 participants. Two patients required a referral to an ophthalmologist. From a psychosocial perspective, 4 participants reported significant difficulties. CONCLUSIONS: This novel tent-based ocular screening program provides a viable option for screening in a pandemic.

Centration of myopic refractive ablation: should we center treatment on the pupil or the visual axis?

The purpose of this study is to compare pupil versus corneal vertex-centered ablation for myopic laser refractive surgery. This study is a retrospective case series of right eyes of consecutive myopic patients undergoing either photorefractive keratectomy (PRK) or laser-assisted in situ keratomileusis (LASIK) with pupil or corneal vertex-centered ablation from January 2018 to April 2018. Overall 258 eyes of 258 patients were included. Of the 104 that underwent LASIK, 52 were treated centered on the corneal vertex (50%), and of the 154 that underwent PRK, 77 were treated centered on the corneal vertex (50%). There were no significant differences in baseline age, gender, spherical equivalence, sphere, cylinder, or angle kappa between both groups in either LASIK or PRK. There were no significant differences between the corneal vertex-centered and pupil-centered groups in terms of efficacy index (LASIK: 1.02 ± 0.14 vs 1.01 ± 0.13, p = 0.86; PRK: 1.00 ± 0.13 vs 0.99 ± 0.15, p = 0.61), safety index (LASIK: 1.02 ± 0.12 vs 1.01 ± 0.13, p = 0.70; PRK:1.02 ± 0.12 vs 1.02 ± 0.09, p = 0.97), and residual astigmatism (LASIK: 0.26 ± 0.25 vs 0.23 ± 0.28, p = 0.65; PRK:0.37 ± 0.41 vs 0.39 ± 0.31, p = 0.78). In mixed effect models, there were no significant differences between the corneal vertex-centered and pupil-centered groups when accounting for angle kappa (p > 0.05). Patients with large angle kappa (> 300 µm) eyes yielded similar results (p > 0.05). For conclusion, in myopic refractive surgery, performing ablation centered on the corneal vertex or on the pupil leads to similar outcomes regardless of the amount of angle kappa.

Descemet Membrane Endothelial Keratoplasty versus Descemet Stripping Automated Endothelial Keratoplasty in Complicated Vitrectomized Eyes.

PURPOSE: Vitrectomized eyes pose a technical challenge when performing endothelial keratoplasty (EK). The aim of the study was to compare outcomes of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) in complex eyes undergoing pars plana vitrectomy (PPV) prior to or during surgery. METHODS: This retrospective study included consecutive eyes that underwent pars plana infusion-assisted DMEK or pull-through DSAEK which underwent PPV prior to or during the EK at a tertiary center. Included were eyes with at least 1-year follow-up. The main outcome measures were best-corrected visual acuity (BCVA) and serious adverse events. RESULTS: Fifty-two eyes (n = 52) with a mean follow-up time of 24.6 ± 7.4 months were included. Both groups were similar in terms of baseline characteristics although the DMEK group had a significantly larger proportion of Fuchs' patients (p = .009). There was no significant difference in postoperative logMAR BCVA between groups at each visit (p > .05 for all). There was a significantly higher proportion of overall serious adverse events (50.0% versus 15.4%, p = .02), retinal detachments (19.2% versus 0.0%, p = .05) and cystoid macular edema (23.1% versus 0.0%, p = .02) following DMEK. Graft detachment occurred more often following DMEK (53.9% versus 11.5%, p = .001) with no significant difference in rebubbling rates (23.1% versus 11.5%, p = .27). CONCLUSIONS: A significant and similar improvement in BCVA was achieved following DMEK and DSAEK in complex vitrectomized eyes. Patients should be advised regarding the higher rates of potential serious complications associated with a pars plana infusion DMEK in this situation.

Visual impairment and the prevalence of ocular pathology in homeless children and adults globally: a systematic review.

BACKGROUND: Homelessness is a global issue in developing and developed countries. This article is the first systematic review to explore its impact on visual health globally. METHODS: A systematic literature search was conducted on OVID MEDLINE, EMBASE, and Cochrane CENTRAL. Peer-reviewed English-language studies with a focus on homeless children or adults that reported on ocular outcomes were included. Primary outcomes and secondary endpoints were reported via weighted averages. Primary outcomes between homeless children and homeless adults were compared using the Fisher exact test. RESULTS: There were 5774 individuals across 23 full-text articles included in the review. For studies reporting primary outcomes, 36.8% of homeless individuals self-reported dissatisfaction with their vision, 26.8% self-reported a previous ocular pathology, 26.3% had uncorrected refractive error, 25.6% were functionally visually impaired, 9.2% had at least one previous eye surgery or procedure, and 4.0% had nonrefractive visual impairment. Upon screening, 25.1% of homeless individuals had some type of ocular pathology, which included cornea and external eye diseases (13.4%), glaucoma (7.4%), cataracts (6.3%), retinal diseases (5.3%), ocular motility disorders (4.7%), trauma (2.3%), neuro-ophthalmological conditions (1.7%), and oculoplastic conditions (0.7%). Homeless adults had significantly more visual impairment (p < 0.001), uncorrected refractive error (p < 0.001), ocular pathology (p < 0.001), cataracts (p < 0.001), retinal pathology (p < 0.001), and neuro-ophthalmological conditions (p < 0.001) relative to children. CONCLUSIONS: Visual impairment in homeless individuals is higher than the general population. Uncorrected refractive error is a leading cause of visual impairment in this population. Additionally, homeless adults have significantly more visual impairment and ocular pathology than homeless children. Future studies should also explore if these differences are consistent in developing countries and investigate ways to increase eye care access for homeless individuals.