The effect of age on lens parameters and axial length among wide age range of Saudis: A prospective, cross-sectional study.

PURPOSE: The purpose of the study is to establish normative values of eye parameters such as lens thickness (LT), lens diameter (LD), and axial length (AXL) among wide age range of Saudis using Pentacam AXL and compare these values between gender, in addition to that, to find the correlation between the age and those parameters. METHODS: In this prospective cross-sectional study, we measured LT, LD, and AXL in 125 healthy Saudi controls aged between 8 and 60 years using OCULUS Pentacam AXL. The screening tests were performed for each subject to exclude any ocular abnormalities using slit lamp (Haag-Streit BQ 900), refractive error measured using auto refractometer (Topcon KR-1 Autorefractor/Keratometer), and subject who has spherical equivalent more than ± 4.00D and astigmatism more than 1.00DC was excluded from the study. The mean of three readings of LT, LD, and AXL was taken. All examination was applied on one eye (right eye). RESULTS: The overall mean and standard deviation of LT, LD, and AXL was 2.2 mm ± 0.5, 2.7 mm ± 0.6, and 23.8 mm ± 1.0, respectively. There was no statistically significant difference between males and females in these parameters in all age groups, except in Group 2 (age: 19-30 years), there was a statistically significant difference between males and females in AXL, mean difference (M = 0.48), and P = 0.015. The mean of LT and LD was negatively associated with age. However, there was no significant correlation between AXL and age. CONCLUSION: Normative values of LT, LD, and AXL have been established in wide age group of healthy Saudis; the findings of the present study can highlight not only the normal range of the different ocular parameters, namely LT, LD, and AXL, but also their variation with age and gender.

Relationship between lens parameters and ocular anatomical characteristics in myopia patients / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To investigate the relationship among lens parameters and their correlation with ocular anatomic characteristics in myopia patients implanted with posterior-chamber phakic implantable collamer lens(Phakic-ICL).METHODS:Retrospective study. A total of 46 myopia patients(46 eyes)who underwent Phakic-ICL implantation were collected in the Wuxi Huaxia Eye Hospital from June 2022 to June 2023. Preoperative evaluation of ocular anatomical characteristics included corneal central thickness(CCT), anterior chamber depth(ACD), axial length(AL), white-to-white(WTW), horizontal sulcus to sulcus(STSH), horizontal angle to angle(ATAH), and vertical sulcus to sulcus(STSV), vertical angle to angle(ATAV). Furthermore, lens parameters included horizontal crystalline lens rise(CLRH), vertical CLR(CLRV)and vertical lens thickness(LTV). The difference, consistency and correlation of the above parameters were analyzed.RESULTS:Except for differences between WTW and STSV, STSH and ATAV, which were not statistically significant(all P>0.05), the other horizontal and vertical ocular anatomical characteristics were statistically significant(P<0.05). CLRH and CLRV had statistically significant difference(P<0.01), while LTH and LTV were not statistically significant difference(P>0.05). Bland-Altman results revealed that the anatomical characteristics in the horizontal or vertical diameters showed poor consistency. The consistency between CLRH and CLRV was poor. There was consistency between LTH and LTV, with the 95% limits of agreement(LoA)between the differences ranging from -0.21 to 0.28 mm, and the proportion of out-of-line points off the 95% LoA was 4.35%. Pearson correlation analysis revealed that there were correlations between the anatomical characteristics of the horizontal and vertical diameters(P<0.01). Meanwhile, there was no correlation between the anteroposterior diameters(P>0.05). There were correlations between the lens parameters(P<0.05), excepted for the CLRH, LTH and LTV, which had no correlation. AL correlated with the anatomical characteristics of the horizontal and vertical diameters(P<0.05), but it had no correlation with lens parameters(P>0.05). Multiple linear regression analysis revealed that LT=0.419+0.017×age-0.548×ACD+0.371×ATAH+0.884×CLRV, CLRH=-0.443+0.809×CLRV, CLRV=-0.092-0.200×ATAH+0.560×CLRH(corrected R2=0.458, 0.482, 0.589, respectively).CONCLUSION:Horizontal and vertical diameters were not interchangeable. CLRH and CLRV were not interchangeable, while LTH and LTV were interchangeable. Partial lens parameters, WTW, STS, and ATA were correlated with ACD. Finally, age, ACD, ATAH, and CLRV influenced LT.

A comparison of lens parameters in patients with various subtypes of primary angle-closure disease and the normal population: A prospective study.

Purpose: To assess the role of lens parameters in the detection and progression of primary angle-closure disease (PACD) by combining A-scan and A-scan optical coherence tomography (AS-OCT) parameters. Methods: A cross-sectional study was conducted in a tertiary health-care center in eastern India. A total of 91 study subjects including cases and controls were included in the study. The parameters studied were lens thickness (LT), lens axial factor (LAF), relative lens position (RLP), and lens vault (LV). Anterior chamber depth (ACD) and axial length (AL) were also analyzed using A-scan. Results: The LT was significantly more in all subtypes of PACD (from 4.24 ± 0.84 to 5.02 ± 0.18 mm) than in controls (4.04 ± 0.46 mm; P < 0.01). Similarly, LAF was significantly less among all subtypes of PACD compared to controls (P < 0.001). The RLP, calculated using the formula (ACD + 0.5 LT)/AL × 10, showed no significant difference (P > 0.05) between various study groups. The LV in acute angle-closure glaucoma (AcCG) patients was significantly higher compared to the control population (P < 0.01). Ocular parameters like ACD decreased, whereas LT and LAF increased from normal through primary angle closure (PAC) to primary angle-closure glaucoma (PACG). Logistic regression analysis found a significant association between a decrease in ACD and an increased risk of PACG (P-value was 0.0001) and an increase in LT and LAF with increased risk of PACG (P = 0.040 and P = 0.006, respectively). Conclusion: Inclusion of lens parameter assessment in the workup of a patient with PACD helps in detection and close monitoring of the progression from suspected to disease state.

All soft contact lenses are not created equal.

Soft contact lenses that have been prescribed by eye care practitioners are sometimes substituted for alternative lenses by unqualified, unregulated and sometimes even fully regulated lens suppliers, in the mistaken belief that there is essentially no difference between different soft lens types. This review considers the implications of inappropriately substituting soft contact lens types in terms of (a) lens properties: surface treatment, internal wetting agents, material, total diameter, back optic zone radius, thickness, edge profile, back surface design, optical design, power, colour (tint) and ultraviolet protection; and (b) lens usage: wearing modality (daily versus overnight wear) and replacement frequency. Potential aspects of patient dissatisfaction and adverse events when prescribed soft lenses are substituted for lenses with different properties or intended usage are considered. Substitution of 15 of the 16 lens properties considered (i.e. except for back surface design) was found to be related to at least one - and as many as six - potential sources of patient dissatisfaction and adverse ocular events. Contact lens are medical devices which are prescribed and fitted; they should never be substituted for another lens type in the absence of a new prescription further to a full finalised fitting, for the simple reason that all soft contact lenses are not created equal. A substituted lens may have properties that results in undesirable consequences in respect of vision, ocular health, comfort and cosmetic appearance, and may be incompatible with the lifestyle of the patient.