Repeatability of pupil size measurements with NIDEK OPD-Scan III in myopic children.

OBJECTIVE: To investigate the repeatability of pupil size measurements, determined from the NIDEK OPD-Scan III, of myopic eyes in children wearing single-vision spectacles (SVS), undergoing orthokeratology (OK) and receiving combined treatment of 0.01% atropine and orthokeratology (AOK). METHODS: A single examiner took two sets of mesopic pupil size measurements from the right eyes of 80 children (SVS:16, OK: 34, AOK: 30) (mesopic 1 and mesopic 2) and two sets of photopic (photopic 1 and photopic 2) pupil size measurements (internal light source) using the NIDEK OPD-Scan III. Each set was taken at a single visit, 15 min apart. Subjects in the OK and AOK groups had undergone treatment for at least 6 months, and the SVS subjects had no previous myopia treatment other than wearing spectacles. Repeatability of measurements was analysed using intraclass correlation coefficient (ICC), Bland-Altman (BA) plot, and coefficient of repeatability (CoR). RESULTS: Mesopic 1 and 2 values were not significantly different among the three groups (p = 0.56, 0.77), hence the data were pooled for each set of measurements (mean [±S.D.] values were 7.09 ± 0.61 and 7.12 ± 0.61 mm, respectively) for further analyses. ICC for repeated mesopic pupil size measurements was 0.98 (95% CI, 0.98-0.99). No significant correlation was found between the means of the mesopic 1 and 2 measurements and their differences (Pearson's r = -0.02, p = 0.83). A BA plot also demonstrated narrow 95% limits of agreement, with a CoR of 0.28 mm. Mean photopic 1 and 2 measurements for the AOK group (3.74 ± 0.46; 3.73 ± 0.43 mm, respectively) were significantly larger (p = 0.01; 0.009) than those of the SVS and OK groups, but no significant difference was found between the latter two groups (p > 0.05). Hence, photopic 1 and 2 measurements for the SVS and OK groups were pooled (SVS-OK) for further analyses. ICC for repeatability of the photopic measurements was 0.98 (95% CI, 0.96 to 0.99) for the SVS-OK and AOK groups. The differences between photopic 1 and 2 measurements were not significantly correlated with their means, either in the AOK group (Pearson's r = -0.25, p = 0.19), or in the pooled SVS-OK group (Pearson's r = -0.04, p = 0.78). BA plots also showed narrow 95% limits of agreement, and CoR was 0.25 mm and 0.23 mm in the AOK and pooled SVS-OK groups, respectively. CONCLUSION: Mesopic and photopic pupil size measurement using the NIDEK OPD-Scan III was highly repeatable and suitable for use on children.

One-year results of 0.01% atropine with orthokeratology (AOK) study: a randomised clinical trial.

PURPOSE: To report the 1-year results of an investigation into whether there is an additive effect between 0.01% atropine and orthokeratology (ortho-k), in a single-masked, two-arm, randomised controlled trial: Combined Atropine with Orthokeratology (AOK) for myopia control study (ClinicalTrials.gov number: NCT02955927). METHODS: Chinese children aged between 6 and 11 years with 1.00-4.00 D of myopia, astigmatism <2.50 D, and no more than 1.00 D anisometropia, were randomly assigned either to an AOK group or ortho-k only (OK) group at a 1:1 ratio. Subjects in the AOK group instilled one drop of 0.01% atropine into each eye, 10 min before nightly wear of ortho-k lenses. The primary outcome, axial elongation, was examined at 6-monthly intervals, along with secondary outcomes including best-corrected visual acuity (BCVA), manifest refraction, accommodation, pupil size, and corneal topography. RESULTS: 29 AOK and 30 OK subjects completed the 1-year visit. The overall axial elongation rate was significantly slower in the AOK group than in the OK group (mean (S.D.), 0.07 (0.16) mm vs 0.16 (0.15) mm, respectively; p = 0.03). A significant between-group difference in axial elongation was observed over the first 6-month period only (p < 0.001), but not over the second period (p = 0.818). At the 1-year visit, increases in mean (S.D.) mesopic and photopic pupil sizes in the AOK group were 0.64 (0.48) mm and 0.36 (0.34) mm, respectively, which were significantly higher than 0.10 (0.50) mm and 0.02 (0.28) mm in the OK group (p < 0.001). At the 6-month visit, a significant moderate negative correlation was found between axial elongation and the increase in photopic pupil size (r = -0.42, p = 0.02) in the AOK group. CONCLUSIONS: There is an additive effect between 0.01% atropine and ortho-k over one year, with mean axial elongation in the AOK group 0.09 mm slower than that in the OK group. It appears that the additive effect was only during the first six months; a second-year investigation is warranted to determine whether the effect is sustained over time.

Combined 0.01% atropine with orthokeratology in childhood myopia control (AOK) study: A 2-year randomized clinical trial.

BACKGROUND: To investigate whether combining 0.01% atropine with orthokeratology (AOK) has a better effect in retarding axial elongation, compared with orthokeratology alone (OK) over two years. METHODS: A total of 96 Chinese children aged six to < 11 years with myopia (1.00 - 4.00 D, inclusive) were randomized into either the AOK or OK group in a 1:1 ratio. Axial length (the primary outcome), and secondary outcomes (e.g. pupil size and choroidal thickness) were measured at 1-month and at 6-monthly intervals after commencement of treatment. RESULTS: Both intention-to-treat and per-protocol analyses showed significantly slower axial elongation in the AOK group than OK group over two years (P = 0.008, P < 0.001, respectively). AOK subjects had statistically slower axial elongation (adjusted mean [standard error], 0.17 [0.03] mm vs 0.34 [0.03] mm, P < 0.001), larger increase in mesopic (0.70 [0.09] mm vs 0.31 [0.09] mm, P = 0.003) and photopic pupil size (0.78 [0.07] mm vs 0.23 [0.07] mm, P < 0.001), and greater thickening of the choroid (22.6 [3.5] µm vs -9.0 [3.5] µm, P < 0.001) than OK subjects over two years. Except for a higher incidence of photophobia in the AOK group (P = 0.006), there were no differences in the incidence of any other symptom or adverse events between the two groups. Slower axial elongation was associated with a larger increase in the photopic pupil size and a greater thickening in the choroid in the AOK group. CONCLUSIONS: Slower axial elongation following 2-year AOK treatment may result from increased pupil dilation and a thickening in the choroid observed in the AOK group.

Combined accelerated collagen crosslinking and sub-Bowman's keratomileusis in high myopic eyes: a comparison between total ultraviolet energy dose.

AIM: To compare the safety, efficacy, and predictability outcomes of combined sub-Bowman's keratomileusis (thin flap laser in situ keratomileusis [LASIK]) and accelerated crosslinking (CXL) using two different irradiation durations. METHODS: A retrospective comparative study of patients with percent tissue altered ≥35%, undergoing simultaneous CXL during sub-Bowman's keratomileusis were recruited. Following riboflavin application, they underwent ultraviolet-A (UVA) irradiation (18 mW/cm2) for either 2 min (total energy 2.16 J/cm2) or 3 min (total energy 3.24 J/cm2). Visual and refractive outcomes were compared between follow-up visits during the first year postoperatively. Demarcation line and endothelial cell count were evaluated, respectively, at 1 and 3 months postoperatively. RESULTS: The baseline characteristics were similar between the 40 eyes/patients treated using the 2-min protocol and the 33 eyes/patients treated with the 3-min protocol (p ≥ .114). Uncorrected distance visual acuity and corrected distance visual acuity were significantly better for eyes treated with the shorter irradiation protocol on Day 1 (p ≤ .030) and Month 1 (p ≤ .040) postoperatively; these differences diminished by Month 3 (p ≥ .070). Likewise, the efficacy index was higher during the first postoperative week for the 2-min protocol (p ≤ .043). At 1 year, the proportion of eye attaining within 0.5 D of target refraction was 80.0% and 84.8% for the 2-min and 3-min protocols, respectively (p = .590). The corresponding corneal stromal demarcation line depth and endothelial cell density changes were comparable between the two groups (p = .311 and 0.899, respectively). CONCLUSIONS: A comparable volume of crosslinked corneal tissue can be achieved by using a shorter UVA irradiation duration. Additional duration of UVA irradiation could lead to delay in visual rehabilitation after simultaneous sub-Bowman's keratomileusis and CXL.

Epidemiological factors associated with health knowledge of three common eye diseases: A community-based pilot survey in Hong Kong.

OBJECTIVES: To assess the proportions of respondents in the general community having heard or awareness, and their knowledge level, of three common eye diseases: age-related macular degeneration, cataract, and glaucoma. We also attempted to assess for risk factors that may be associated with any variations, which will help identify the areas of inadequate knowledge and demographics of potential audiences for focused health education. METHODS: We conducted a community-based pilot survey for the residents from a southern suburb of Hong Kong in early 2016, by inviting all aged 50 or above to complete a standardized questionnaire in the local community hall. RESULTS: Most of the 222 respondents have heard, or awareness, of cataract (92.79% or 81.98%, respectively), followed by glaucoma (86.94% or 52.70%, respectively), and age-related macular degeneration (51.35% or 29.28%, respectively). The results of Cronbach's alpha (α > 0.7) and Spearman's correlation coefficient (p < 0.01) suggested that the internal consistency, convergent and discriminant validities of the questionnaire were acceptable for the study population. Compared to a previous Hong Kong survey in 2002, the proportions of having heard of the three eye diseases were greater, but the overall knowledge remained limited. From a maximum knowledge score of 29, the median scores for age-related macular degeneration, cataract, and glaucoma were 9, 13, and 14, respectively. Except for the treatment of cataract, the knowledge level in most areas was low. Sociodemographic factors and medical history, rather than behavioral factors, were more likely to be associated with having a higher knowledge level. Subjects with family or friends with a history of glaucoma or age-related macular degeneration were more aware and knowledgeable, but not for subjects who were current and past smokers or alcohol drinkers. For age-related macular degeneration, gender modified the effect between age and knowledge level, while age was a confounder of having medical history, and having heard or awareness, of the disease. CONCLUSION: Despite a larger proportion of the community having heard or awareness since 15 years ago, much effort remains for improving health knowledge of these three eye diseases in Hong Kong. We recommend targeting respondents with higher lifestyle risks, such as current and past smokers or alcohol drinkers, as a focused audience, and utilizing family members, relatives, or friends as another way of distributing health information.

Changes in Corneal Volume at Different Areas and Its Correlation with Corneal Biomechanics after SMILE and FS-LASIK Surgery.

PURPOSE: To investigate the variations of corneal volume (CV) after small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and analyze the influences of biomechanical properties on the changes of refraction and CV. METHODS: Ninety-seven eyes of 97 patients undergoing SMILE and FS-LASIK were included in this retrospective study. CV was measured with Scheimpflug-based corneal topography at preoperatively and at day 1, week 1, and months 1 and 3 postoperatively. CV measured within 5 mm diameter was defined as central region volume (CV5) and between 5 mm and 10 mm diameter was defined as peripheral region volume (CV5-10). An Ocular Response Analyzer (ORA) was used to assess corneal biomechanical properties including corneal hysteresis (CH) and corneal resistant factor (CRF). The reduction of study parameters (△) were calculated by subtracting the preoperative value at various time points from the postoperative values. RESULTS: CV had significant reduction after the SMILE and FS-LASIK procedure (P < 0.05). CV5 increased significantly from postoperative day 1 to month 3 (P < 0.001) in SMILE, while both CV5 and CV5-10 increased significantly in FS-LASIK (P < 0.001). The increase in CV5 after SMILE was 0.11 ± 0.16 mm3，which was significantly different from FS-LASIK (0.20 ± 0.13 mm3, P=0.004). In the SMILE group, △CV5 correlated with △CRF (r = 0.498, P < 0.001) and △CH (r = 0.374, P=0.007). In the FS-LASIK group, △CV5 and △CRF had a significant correlation (r = 0.363, P=0.012), but not with △CH. CONCLUSIONS: Dynamic changes in corneal volume were found after SMILE and FS-LASIK surgery. The central region significantly increased after SMILE, while both central and peripheral regions increased following FS-LASIK in the early postoperative period. SMILE was associated with less change in biomechanical properties per unit of reduction in CV compared with FS-LASIK.

Combined Atropine with Orthokeratology for Myopia Control: Study Design and Preliminary Results.

Purpose: The purpose of this study is to present the study design and one month's preliminary results of a 2-year randomized trial, Combined Atropine with Orthokeratology (AOK), for myopia control study. Methods: Children aged 6 to <11 years and with 1.00-4.00 D myopia were randomly assigned to AOK group or ortho-k alone (OK) group. Subjects are required to attend routine ortho-k aftercare visits (first-overnight, 1 week, 2 weeks, 3 weeks, 1 month, and every 3 months after commencement of lens wear). Clinical outcomes, including lens performance, changes in refractive error, unaided vision, ocular adverse events, corneal staining, lens binding and centration, and axial length, are also assessed at 6-monthly data collection visit. Results: Data of 30 AOK and 34 OK subjects who had completed the 1-month visit were analyzed. No significant differences in baseline data were found between the two groups (P > 0.05). At the 1-month visit, first-fit success rate was 95%, with full myopia reduction. Mild corneal staining was observed in 23.3% and 30.9% and mild self-reported lens binding in 50% and 41% in AOK and OK groups, respectively, after 1-month lens wear. Mean (±standard deviation) change in axial length was significantly higher in AOK than OK subjects (AOK: -0.05 ± 0.05 mm; OK: -0.02 ± 0.03 mm) (P = 0.003). Conclusions: After 1 month of treatment, first-fit success rate of ortho-k lenses was high in both groups of subjects; addition of 0.01% atropine in AOK subjects did not affect the lens performance or clinical responses. These results provide the assurance that it is acceptable to continue this longitudinal study, as longer study duration, usually 2 years, is required to determine the effectiveness of treatment for myopia control.

Increase in omega-6 and decrease in omega-3 polyunsaturated fatty acid oxidation elevates the risk of exudative AMD development in adults with Chinese diet.

Appropriate diet is essential for the regulation of age-related macular degeneration (AMD). In particular the type of dietary polyunsaturated fatty acids (PUFA) and poor antioxidant status including carotenoid levels concomitantly contribute to AMD risk. Build-up of oxidative stress in AMD induces PUFA oxidation, and a mix of lipid oxidation products (LOPs) are generated. However, LOPs are not comprehensively evaluated in AMD. LOPs are considered biomarkers of oxidative stress but also contributes to inflammatory response. In this cross-sectional case-control study, plasma omega-6/omega-3 PUFA ratios and antioxidant status (glutathione, superoxide dismutase and catalase), and plasma and urinary LOPs (41 types) were determined to evaluate its odds-ratio in the risk of developing exudative AMD (n = 99) compared to age-gender-matched healthy controls (n = 198) in adults with Chinese diet. The odds ratio of developing exudative AMD increased with LOPs from omega-6 PUFA and decreased from those of omega-3 PUFA. These observations were associated with a high plasma omega-6/omega-3 PUFA ratio and low carotenoid levels. In short, poor PUFA and antioxidant status increased the production of omega-6 PUFA LOPs such as dihomo-isoprostane and dihomo-isofuran, and lowered omega-3 PUFA LOPs such as neuroprostanes due to the high omega-6/omega-3 PUFA ratios; they were also correlated to the risk of AMD development. These findings indicate the generation of specific LOPs is associated with the development of exudative AMD.

Dietary Habits, Fatty Acids and Carotenoid Levels Are Associated with Neovascular Age-Related Macular Degeneration in Chinese.

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 -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.

Effect of location of opening incision on astigmatic correction after small-incision lenticule extraction.

We compared the visual and refractive outcomes between 2 different incisional sites in small incision lenticule extraction (SMILE) for low myopic astigmatism. This was a contralateral eye study. Consecutive cases that underwent bilateral SMILE surgery were included. Procedures for both eyes were identical apart from the location of opening incision. The incision was set on the temporal side for the right eye (Group 1), while a superior incision was set for the left eye (Group 2). Twenty-nine patients with a mean age of 35.0 ± 9.6 years were included. Preoperative visual and refractive parameters were comparable between the 2 groups (p > 0.250). At 3 months, the logMAR uncorrected distance visual acuity was 0.074 ± 0.090 in Group 1 and 0.084 ± 0.130 in Group 2 (p = 0.861). No difference was found in the postoperative manifest spherical equivalent (p = 0.501) and manifest cylinder (p = 0.178) between the 2 groups. The efficacy index was 0.85 ± 0.16 in Group 1 and 0.85 ± 0.20 in Group 2 (p = 0.828). Astigmatic correction was not significantly affected by the location of opening incisions using vector analysis. Our study did not find significant differences in visual and refractive outcomes with temporal or superior opening incision during SMILE surgery.

Review on the Management of Primary Congenital Glaucoma.

Despite being documented in medical history from over 2400 years ago, primary congenital glaucoma (PCG), being a disease with low incidence rate, remains a challenge to ophthalmologists. The article provides a broad overview on the pathophysiology and diagnostic approach to PCG with major emphasis on the treatment options of PCG. While reviewing on the well-established treatment options, namely goniotomy, trabeculo-tomy and combined trabeculotomy-trabeculectomy, emphasis has also been made to recent updates on secondary treatments: trabeculectomy, antimetabolites, glaucoma-drainage devices and cyclodestructive procedures. It is, however, important to note that the rarity of PCG places limitations on study design, most studies are, thus, retrospective, nonrandomized and have different definitions of surgical success. Ophthalmologists need to interpret the results with critical thinking and formulate individual treatment plans for each patient. How to cite this article: Yu Chan JY, Choy BNK, Alex LK Ng, Shum JWH. Review on the Management of Primary Congenital Glaucoma. J Curr Glaucoma Pract 2015;9(3):92-99.