Objective To evaluate the repeatability and agreement of two optical biometers (Lenstar LS900 (R) and SW-9000) for ocular biometry in Chinese adolescents.Methods A prospective study was conducted which included 65 ametropic patients,with an average age of (11.45 ± 2.67) years (age ranging from 8 to 18 years).The ocular biometry for right eyeball was performed with Lenstar LS900 (R) and SW-9000 respectively,followed by evaluation of the repeatability of the two biometers using one-way analysis of variance,and the agreement of the two instruments using the Bland-Altman plot.Results The repeatability of parameters measured by Lenstar LS900 (R),including axial length (AL),K value in the flattest meridian (K1),K value in the steepest meridian (K2),central corneal thickness (CCT),anterior depth (AD),lens thickness (LT),pupil diameter (PD),was well,and all intraclass correlation coefficient (ICC) ＞ 0.9;the repeatability of white to white (WTW) was inferior to other parameters,but it was still ＞0.88.The repeatability of AL,K1,K2,CCT measured by SW-9000 was good,with their ICC ＞ 0.9,but the repeatability of other parameters was poor.The parameters with good repeatability including AL,K1,K2,CCT measured by SW-9000 and Lenstar LS900 (R) were compared respectively,and the results showed that AL and CCT examined by SW-9000 were slightly longer than those measured by Lenstar LS900 (R),and the difference was statistically significant (all P ＜ 0.05).However,there was no significant difference about K1,K2 (all P＞0.05).Moreover,the AL,K1,K2 and CCT measured by the two instruments had close linear correlation (all r ＞0.97,all P ＜0.01).The BlandAltman plot showed that 95％ LoA (limits of agreement) of AL was (-0.057 to 0.133) mm,K1 was (-0.456 to 0.369) D,K2 was (-0.388 to 0.549) D and CCT was (-3.483 to 8.016) μm.Conclusion Biometric parameters including AL,K1,K2,CCT measured by Lenstar LS900 (R) and SW-9000 have good repeatability in the adolescents aged 8-18 years and they are highly correlated;meanwhile,the agreement of AL,K1,K2,CCT measured by SW-9000 with Lenstar LS900 (R) is acceptable in clinical practices.

Objeetive To compare corneal densitometry measured by Pentacam in normal and keratoconic eyes,and assess the differences in densitometry values among the stages of keratoconus.Methods Densitometry values for 66 eyes (36 eyes from keratoconus group,30 eyes from control group) were obtained for the 0-2 mm,2-6 mm,and 6-10 mm zones of the anterior (up to 120 mm),posterior (posterior 60 mm),and central (between the anterior and posterior) cornea.The differences in densitometry values among the stages of keratoconus were compared.Pearson correlation analysis was used to access the relationship among Keratoconus optical density,cornea thickness and flat K values.1~l~ In total diameter,the corneal densitometry between keratoconus group (17.96 ± 3.23) and control group (17.39 ± 1.95) was not significant different(P =0.124),but there were significant differences between the groups for densitometry measurements in central 2.0 mm zones(anterior,central and total layers),annulus 2-6 mm(anterior layers) and anterior layers in total diameter (all P ＜0.05).Divided by different stage of keratoconus,the anterior layer in mild Keratoconus had no difference with control group(P ＞0.05),but therewere significant differences in moderate keratoconus group(all P ＜ 0.05).In severe Keratoconus group,a statistically significant difference was present at the 2 central annuli in total thickness and annulus 2-6 mm (anterior,central and total layers) with control group (P ＜ 0.05).The correlation between corneal densitometry and the other parameters,including cornea thickness and flat K values were significant (all P ＜ 0.05).Conelusion Compared with normal cornea,there is no change in mild keratoconus.The increase of corneal densitometry in moderate keratoconus group happens in the anterior layers of 0-2 mum zones.The anterior layers of 0-6 mm zones and central layers in 0-2 mm zones in severe keratoconus group are higher than those of control group.More advanced cases present a higher corneal densitometry.Corneal densitometry is an important characteristic of keratoconus,it can be used to detect the process and therapeutic effect of keratoconus.

Objective:To evaluate the clinical features of interface fluid syndrome (IFS) after laser in situ keratomileusis (LASIK).Methods:We searched PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure Database, Wanfang Database, and Chinese Science and Technology Periodical Database for literature reports on IFS published from 1999 to 2021.Article selection, data extraction, quality rating, and data analysis were performed with reference to the PRISMA statement for priority reporting entities of systematic reviews and Meta-analysis.Results:A total of 30 publications were included, including 46 cases (62 eyes). Among them, 34 cases (47 eyes) were male and 12 cases (15 eyes) were female.Age ranged from 19 to 69 years with a mean of (36.57±13.40) years.There were 16 cases of bilateral eyes and 30 cases of monocular eyes.The 85.48% (53/62) of IFS was due to increased intraocular pressure (IOP) after LASIK.All 62 eyes included had decreased visual acuity.The 24.19% (15/62) of the affected eyes had ocular pain, redness, and photophobia.All 46 patients showed different degrees of corneal edema and interface fluid.Keratic precipitates and anterior chamber cells were visible in 9.68% (6/62) of the affected eyes, and 16.13% (10/62) showed visual field damage.IOP-lowering eye drops were given to 77.42% (48/62) of eyes.Of the 31 patients (40 eyes) with prognostic descriptions, and 75.00% (30/40) recovered their vision with treatment and 25.00% (10/40) did not.Conclusions:IFS is a rare complication after LASIK.It should be considered in patients with corneal edema after LASIK.Proper measurement of IOP and reasonable application of glucocorticoids and IOP-lowering drops can prevent irreversible vision loss.