Comparative study of functional optical zone: small incision lenticule extraction versus femtosecond laser assisted excimer laser keratomileusis.

AIM: To investigate the size of functional optical zone (FOZ) after small incision lenticule extraction (SMILE) versus femtosecond laser assisted excimer laser keratomileusis (FS-LASIK) for myopia correction and potential associated factors for FOZ. METHODS: A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled. There were 63 patients (123 eyes) in SMILE group and 70 patients (139 eyes) in FS-LASIK group. The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery, so as to analyze postoperative achieved functional optical zone (AFOZ) and its contributing parameters. RESULTS: When planned functional optical zone (PFOZ) was 6.5 mm for both groups, AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery. AFOZ in SMILE group was significantly larger than that in FS-LASIK group (P<0.001). Variation of FOZ was negatively correlated with preoperative spherical equivalent (SE) and positively correlated with variation of mean keratometry value (ΔKm), variation of spherical aberration (ΔSA), and variation of Q-value (ΔQ, all P<0.001) in both groups. Multiple variable linear regression equations were ΔFOZ=1.354-0.1×pre-SE+0.336×ΔQ+1.462×ΔSA in SMILE group and ΔFOZ=1.512+0.137×ΔQ+0.468×ΔSA in FS-LASIK group. CONCLUSION: AFOZ is significantly smaller than preoperative FOZ in both SMILE and FS-LASIK groups. With the same PFOZ, larger AFOZ is achieved in SMILE group than in FS-LASIK group.

Therapeutic potential of Rho-associated kinase inhibitor Y27632 in corneal endothelial dysfunction: an in vitro and in vivo study.

AIM: To investigate the effects of a selective inhibitor of Rho-associated kinase (ROCK), Y-27632, on inbred Wuzhishan porcine corneal endothelial cells (PCECs) in vitro and in vivo studies. METHODS: Primary PCECs were trypsinized from Wuzhishan miniature porcine corneal tissues. The optimal concentration of Y-27632 on PCECs was determined through MTT and 5-ethynyl-2'-deoxyuridine (EdU)-labeling assays. Seven New Zealand rabbits were used as a corneal endothelial dysfunction model, and a PCECs suspension supplemented with Y-27632 was injected into the anterior chamber of the rabbits. The progression of rabbit corneal opacity and edema were observed by slit lamp examination. The rabbits were sacrificed, and rabbit globes were enucleated for trypan blue-alizarin red staining, hematoxylin-eosin staining, and immunofluorescence analysis. RESULTS: Administration of 100 µmol/L Y-27632 facilitated PCECs' proliferation obviously. The rabbit corneas injected with PCECs suspension and 100 µmol/L Y-27632 were restored to transparency significantly after 14d. CONCLUSION: The 100 µmol/L Y-27632 treatment improves PCECs' proliferation significantly. And our results suggest that Y-27632 and PCECs can be used to treat corneal endothelial dysfunction.

Clinicopathologic Features and Treatment Characteristics of Congenital Corneal Opacity Infants and Children Aged 3 Years or Less: A Retrospective Single Institution Analysis.

OBJECTIVE: In this retrospective single institution study, we investigated the clinicopathologic features and treatment characteristics of 90 patients with congenital corneal opacities (CCO) (117 eyes) who were 3 years and younger and treated at our hospital. SUBJECT AND METHODS: We reviewed the clinical data of patients with CCO who presented for the first time for treatment at our hospital between January 1, 2017, and December 31, 2017. CCO were classified using the "STUMPED" (Sclerocornea, Tears in Descement's membrane, Metabolic, Peters, Endothelial dystrophy and Dermoid) method and confirmed by pathological examination. -Results: Seventy percent of the patients had unilateral CCO. Iridocorneal adhesions (61 eyes, 52.1%) and cataracts (22 eyes, 18.8%) were the 2 most common ocular abnormalities. Systemic abnormalities were present in 5 patients (5.6%), including growth retardation (4 patients) and congenital brain defects (1 patient). Eighty-five eyes (72.6%) underwent penetrating keratoplasty (PK), and lamellar keratoplasty (LK) was performed in 30 (25.6%) eyes. Forty-seven (95.9%) eyes with Peters anomaly and all 16 eyes with sclerocornea received PK, and all 24 eyes with dermoids were treated with LK. CONCLUSION: Our study demonstrates that CCO has varied manifestations in infants and young children in China. A thorough medical history, careful clinical examination, and the use of accessory examinations such as ultrasound biomicroscopy are critical for the accurate diagnosis and classification of CCO and to provide guidance on therapeutic choices.

Reducing porcine corneal graft rejection, with an emphasis on porcine endogenous retrovirus transmission safety: a review.

Donor cornea shortage is a primary hurdle in the development of corneal transplantation. Of all species, porcine corneas are the ideal transplantation material for humans. However, the xenoimmune rejection induced by porcine corneal xenotransplantation compromises surgical efficacy. Although the binding of IgM/IgG in human serum to a genetically modified porcine cornea is significantly weaker than that of the wild type (WT), genetically modified porcine corneas do not display a prolonged graft survival time in vivo. Conversely, costimulatory blockade drugs, such as anti-CD40 antibodies, can reduce the xenoimmune response and prolong graft survival time in animal experiments. Moreover, porcine endothelial grafts can survive for more than 6mo with only the subconjunctival injection of a steroid-based immunosuppressants regime; therefore, they show great value for treating corneal endothelial disease. In addition, zoonotic transmission is a primary concern of xenotransplantation. Porcine endogenous retrovirus (PERV) is the most significant virus assessed by ophthalmologists. PERV integrates into the porcine genome and infects human cells in vitro. Fortunately, no evidence from in vivo studies has yet shown that PERV can be transmitted to hosts.

Long-term safety of laser in situ keratomileusis in eyes with thin corneas: 5-year follow-up.

AIM: To investigate the long term (≥5y) efficacy, predictability, and safety of laser in situ keratomileusis (LASIK) in eyes with thin corneas [central corneal thickness (CCT) <500 µm]. METHODS: A total of 339 patients met the criteria of this study. Finally, 175 eyes of 89 patients who had thin corneas and underwent LASIK≥5y ago returned to our clinic and included in this study. Preoperative parameters recorded included uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), manifest refraction, CCT and corneal topography. At returning visits, in addition to visual acuity and manifest refraction, ultrasound CCT and corneal topography were performed. Optical coherence tomography was used to measure the CCT, LASIK flap thickness, and residual stromal bed thickness (RSBT). Safety index, efficacy index, percentage of eyes within ±0.5 D and ±1.0 D of refraction, percent tissue altered (PTA), and percentage stromal bed thickness (PSBT) were calculated. RESULTS: The safety index was 1.09 and efficacy index was 0.99. The percentages of eyes within ±0.5 D and ±1.0 D were 71.2% and 87.7%, respectively. The mean PTA was 40%±6% (range 20% to 55%); 76 eyes (43.4%) had PTA <40% and 99 eyes (56.6%) had PTA≥40%. The mean RSBT was 303±27 µm (range 240 to 390 µm), and 2 eyes had RSBT<250 µm. The mean PSBT was 61%±9% (range 51% to 85%). No eyes developed ectasia. CONCLUSION: In this cohort with the PSBT of 50% or more, LASIK is safe with follow-up for at least 5y.