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Purpose To investigate the optic disc and peripapillary vessel density, as well as its ocular and systemic associations, in healthy eyes among adult Chinese population. Methods A population-based cross-sectional eye survey was conducted on Chinese adults residing in Hong Kong. 1891 eyes from 1891 participants who completed 4.5×4.5 mm optical coherence tomography angiography scans were recruited. Among the 1891 eyes, 404 were excluded due to low scan quality, optic disc or retinal disorders and non-Chinese ethnicity. The vessel densities (VDs) at nerve fibre layer plexus (NFLP) at both optic disc and peripapillary were collected for analysis. Multiple linear regression analysis was performed to determine the ocular and systemic associations of NFLP VD. Results The study included 1487 participants (men: 41.2%) with a mean age of 48.8±15.4 years. The mean NFLP VD of the whole en face image, inside disc and peripapillary region was 53.8%, 42.7% and 60.3%, respectively. In the multivariable model, decreased NFLP VDs were significantly associated with older age, male gender, longer axial length (AL) and lower Signal Strength Index. Conclusions This large population-based cross-sectional study provided quantitative data of optic disc and peripapillary NFLP VD which may serve as a normative reference for clinical use. Apart from age, gender and AL, the scan signal strength also should be taken into consideration during the assessment of NFLP VD. [ABSTRACT FROM AUTHOR]

Background We described a modified 'hydroexpression' technique for the lenticule removal during small-incision lenticule extraction (SMILE) surgery and compared the results with conventional forceps method. Methods This was a retrospective, comparative study of 50 patients who underwent SMILE surgery by the same surgeon. We compared the 1-week and 3-months postoperative results after SMILE using the hydroexpression technique with the conventional forceps technique. Main outcome measures included uncorrected distance visual acuity, corrected distance visual acuity, refractive accuracy, safety index and efficacy index. Results The baseline characteristics were comparable between both groups. At postoperative 1 week, the safety index in forceps and hydroexpression group was 0.93±0.11 and 0.97±0.10, respectively (P=0.246). At 3 months, they were 1.00±0.06 and 0.99±0.09 (P=0.850). For efficacy indices, at 1 week they were 0.84±0.17 and 0.91±0.17 (P=0.158). At 3 months, they were 0.92±0.13 and 0.94±0.19 (P=0.624). All eyes aimed for a plano target. 96% in forceps group and 90% in hydroexpression group were within ±0.50 dioptre (D) in spherical equivalent refraction (SEQ) correction at postoperative 3 months (P=0.567). The mean errors of SEQ correction were -0.10±0.21 D in forceps group and -0.08±0.30 D in hydroexpression group (P=0.705). Conclusion Hydroexpression was simple and safe and had early results comparable to the conventional forceps technique. This technique was particularly useful for cases with more adhesions between lenticule and anterior cap, thin lenticule cases and for the inexperienced SMILE surgeons. [ABSTRACT FROM AUTHOR]

PURPOSE: The authors report four cases of residual intrastromal lenticule after seemingly uneventful small incision lenticule extraction (SMILE) surgery and the outcome after a secondary procedure to remove the lenticule remnant. METHODS: Case reports. RESULTS: All four cases presented with suboptimal corrected distance visual acuity (CDVA) and refractive surprise. Irregularities in the corneal curvature and elevation were detected on corneal topography and tomography. Careful review of the intraoperative video showed an incomplete removal of the SMILE lenticule. All four cases underwent a secondary surgical procedure to remove the residual lenticule remnant. All cases had improvements in the CDVA, refraction, and topography, with the CDVA returning to the preoperative value (20/20) in all cases. CONCLUSIONS: Performing an early, secondary lenticular remnant removal operation is feasible, safe, and can result in improvement in both refraction and visual acuity. During the original SMILE surgery, surgeons should routinely examine the removed lenticule for completeness. [ABSTRACT FROM AUTHOR]

Objectives To evaluate and compare the change in corneal biomechanical properties after microincision lenticule extraction (MILE) and small incision lenticule extraction (SMILE). Methods In this prospective study, 60 eyes received MILE surgery with 2 mm opening incision, while 64 eyes received SMILE procedure with 5 mm opening incision. Corneal hysteresis (CH), corneal resistance factor (CRF) and 37 other biomechanical waveform parameters were quantitatively assessed using ocular response analyser (ORA) preoperatively and up to 6 months postoperatively. All changes were calculated as the difference between preoperative and postoperative values (Δ). Results Both CH and CRF values decreased significantly after MILE and SMILE (p<0.001). ΔCRF (o=0.028) and ΔCRF index (ΔCRF/preoperative CRF) (p=0.043) were statistically lower for all eyes at 1-week follow-up. ΔCH index (ΔCH/preoperative CH) was statistically lower at 1-week (p=0.043) and 1-month (p=0.015) follow-ups in MILE group when compared with SMILE group. In both MILE and SMILE group, ΔCH index and ΔCRF index were positively correlated with preoperative manifest refraction spherical equivalent, residual stromal thickness (RST) index (RST/preoperative central corneal thickness) and negatively correlated with lenticule thickness (p<0.05). Conclusions Both MILE and SMILE procedures significantly altered the biomechanical characteristics of cornea. Smaller opening incision was associated with less reduction in ORA parameters during early postoperative period. [ABSTRACT FROM AUTHOR]

PURPOSE: To present the 1-year outcomes of combining monocular bi-aspheric ablation profile and contralateral monofocal LASIK in hyperopic patients with presbyopia. METHODS: In this retrospective case series, 36 consecutive patients (72 eyes) who underwent simultaneous bi-aspheric ablation (PresbyMAX: SCHWIND Eye-Tech-Solutions GmbH and Co KG, Kleinostheim, Germany) in the non-dominant eye and monofocal regular LASIK in the dominant eye for correction of hyperopia and presbyopia were reviewed for 1 year. Binocular uncorrected distance (UDVA), near (UNVA), corrected distance (CDVA), and distance corrected near (DCNVA) visual acuity and manifest refraction were analyzed postoperatively. RESULTS: At 1 year, the mean binocular UDVA improved significantly from 0.26 ± 0.25 to 0.039 ± 0.088 logMAR (P < .001). Binocular UNVA also improved from 0.73 ± 0.30 to 0.10 ± 0.22 logRAD (P < .001). Eighty-seven percent of patients achieved UDVA of 20/25 or better and 90% had UNVA of J3 or better. Simultaneous binocular distance and near vision of 20/25 and J2 or better was achieved in 70%. Only 17% of patients had a binocular DCNVA of J2 or better. No patient suffered from a loss of 2 lines of CDVA. Refractive stability was achieved for both eyes from 1 month postoperatively. The re-treatment rate was 14% for improvement of near vision within 6 months to 1 year. CONCLUSIONS: Presbyopic correction using monocular PresbyMAX combined with monofocal regular LASIK in the fellow eye is safe and acceptable in hyperopic patients. [ABSTRACT FROM AUTHOR]

Background/aims This was a cross-sectional survey to find the prevalence of visual impairment and eye diseases among adults with Down syndrome (DS) in Hong Kong. Methods 91 DS patients over the age of 30 were recruited through the Hong Kong Down Syndrome Association. Each patient was provided with a complete ophthalmological assessment including best corrected visual acuity, refraction, slit lamp and fundus examination. Results In our sample, 56.6% had normal vision to mild vision impairment, 33.7% and 7.2% had moderate and severe vision impairment, respectively, and 2.4% were blind. The mean presenting distant LogMAR visual acuity was 0.66 (Snellen equivalent 20/90), and the best corrected LogMAR visual acuity was 0.48 (Snellen equivalent 20/60). Significant refractive errors were found in 86.3% of the eyes, with spherical equivalent corrections ranging from ?23.25D to +3.00D. Myopia and astigmatism were prevalent and found in 59.3% and 72.7% of the eyes, respectively. Blepharitis and chalazion were found in 44% of the eyes, while corneal problems were present in 27.5%. There were low incidences of infective keratitis (0.5%), keratoconus (0.5%) and Brushfield spots (1.1%). Cataracts were found in 72.2% of the eyes; 26.1% were congenital and 44.9% were age-related. Fundal abnormalities were present in 49.5% of the eyes. Conclusions There is a high prevalence of vision impairment among Chinese DS adults. Uncorrected refractive errors, high myopia and cataracts are the main visually debilitating ophthalmological abnormalities. Vision may be improved through the simple use of glasses and early treatment of age-related cataracts. [ABSTRACT FROM AUTHOR]

The role of diet and circulatory carotenoids and docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) are implicated in age-related macular degeneration (AMD) but not well studied in Chinese. However, other fatty acids were not comprehensively evaluated if it had additional consequence on AMD. This study investigated the relationship among dietary habits, fatty acids levels, carotenoids and AMD in Hong Kong Chinese adults. In this cross-sectional case-controlled study, plasma fatty acids including, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), and carotenoids levels were quantified between patients with neovascular AMD (n = 99) and age-gender-matched controls (n = 198). A food frequency questionnaire was also conducted. Low blood carotenoid levels and omega-3 PUFAs namely DHA, EPA and α-linolenic acid increased the odds ratio of developing neovascular AMD. High blood omega-6 PUFAs specifically arachidonic acid and eicosadienoic acid, oleic acid (a MUFA) and SFA levels increased the odds ratio of having neovascular AMD. Neovascular AMD group had significantly less omega-3 PUFA rich food (vegetables, nuts, seafood) intake and higher SFA (meat) intake than controls. In short, neovascular AMD was associated with lower circulatory levels of carotenoids and omega-3 PUFAs, and higher level of omega-6 PUFAs, oleic acid and SFAs in the Hong Kong Chinese population. These findings enhance the understandings of dietary impacts on neovascular AMD and provide a context for future nutritional intervention studies. [ABSTRACT FROM AUTHOR]