Corneal Diameter Research Articles

Analyzing Anatomical Factors Contributing to Angle Closure Based on Anterior Segment Optical Coherence Tomography Imaging

ABSTRACT Purpose To analyze anatomical factors contributing to angle closure based on anterior segment optical coherence tomography (AS-OCT) imaging. Methods A total of 238 patients with angle closure and 1122 normal controls were consecutively recruited for this study. Participants’ eyes were imaged using AS-OCT under the same darkened ambient light conditions. The following parameters were analyzed: central anterior chamber depth (ACD); anterior chamber area (ACA); anterior chamber volume (ACV), anterior chamber width (ACW); corneal diameter (CD); posterior cornea curvature (PCC); anterior cornea curvature (ACC); maximum iris thickness (ITM); iris thickness at 750 um (IT750) and 2000 um (IT2000) from the scleral spur; iris curvature (IC); iris area (IA); lens vault (LV); angle opening distance (AOD); trabecular iris space area at 500 um (TISA500) and 750 um (TISA750) from the scleral spur; angle recess area (ARA). Lasso regression models were used to detect the collinearity of parameters. The multivariable logistic regression was performed to determine the independent association between angle closure and those parameters included in Lasso regression model. Also Factor analysis was performed to extract a few underlying factors (components) from these parameters. Results Lasso regression showed that ACD, ACV, PCC, IT750, IT2000 and LV were screened in the model. The multivariable logistic regression indicated that ACV, PCC, IT750 and LV were significantly associated with angle closure. Factor analyses revealed that 4 factors, each with its closely associated clusters of variables, produced the best results: ACA, ACV and ACD (Factor 1); LV, tIC and nIC, (Factor 2); ACW, CD and PCC (Factor 3); and tITM, tIT2000, tIT750, nIT2000 and nIT750 (Factor 4). Conclusions Four separate mechanisms were showed to be involved in the pathogenesis of angle closure, from anterior chamber dimensions, lens, iris and cornea respectively. The parameters ACV, PCC, IT750, and LV are more predominant in determining angle closure.

Primary X-linked megalocornea presenting in adulthood

A48-year-old visually asymptomatic male was referred for assessment of possible arrested congenital glaucoma. No relevant medical or family history were reported and the visual acuities and intraocular pressures were within normal limits bilaterally. Examination revealed prominent arcus lipoides (Figure 1A), crocodile shagreen (Figure 1B), mild cataract and an open, heavily pigmented iridocorneal angle in each eye. Fundoscopy was unremarkable with healthy optic discs. Further evaluation revealed horizontal corneal diameter of 14mm (Figure 1C), central corneal thickness of ∼410µm and anterior chamber depth of 6mm bilaterally.

The crested caracara (Caracara plancus) eye: Morphologic observations and results of selected diagnostic tests.

To provide a descriptive investigation about relevant features of the crested caracara's eye (Caracara plancus) and bony orbit, as well as provide data for ophthalmic tests. Morphological observations and the following diagnostic tests were performed: Schirmer tear test (STT), conjunctival flora evaluation, corneal touch threshold (CTT), intraocular pressure (IOP), central corneal thickness (CCT), B-mode ocular biometry, palpebral fissure length (PFL), and corneal diameter (CD) in 19healthy birds, plus two macerated skulls. Not all birds were used for each test. STT: 7.84±3.05mm/min; CTT: 2.46±1.10cm; IOP: 19.18±3.07mmHg; CCT: 0.31±0.02mm; PFL: 13.32±1.06mm; CD: 10.26±2.43mm; Axial globe length: 1.89±0.06cm; Anterior chamber depth: 0.27±0.06cm; Lens axial length: 4.55±0.06cm; Vitreous chamber depth: 1.2±0.07cm. The most frequent conjunctival bacterial isolates were Corynebacterium sp. (10/23.8%), Staphylococcus sp. (9/21.42%), Streptococcus sp. (7/16.6%), and E.coli (7/16.66%). The large lateral part of the palatine bone likely plays a role in the ventral protection of the globe against the impact of prey. Observed results are generally reflective of increased body mass compared to other Falconiformes, with values approaching those of similar sized Accipitriformes. These data may help veterinarians recognize peculiar morphologic features and perform a more accurate diagnosis of eye diseases of this avian species.

Primary Congenital Glaucoma among the Children Under 3 Years of Age in the Outpatient Department in a Tertiary Care Hospital: A Descriptive Cross-sectional Study.

Primary congenital glaucoma is a rare vision-threatening condition of children. Primary congenital glaucoma though a rare disease it is the most common cause of childhood glaucoma with potency to cause blindness. This study was undertaken to find the prevalence of the children with primary congenital glaucoma under 3 years of age in a tertiary care hospital. This was a descriptive cross-sectional study conducted at a tertiary eye center in Nepal in children (≤ 3 years) presented in the outpatient department of a tertiary eye hospital between June 2017 and June 2020. The study was approved by the hospital review committee and adhered to the declaration of Helsinki. A convenient sampling method was used. Point estimate at 95% Confidence Interval was calculated with frequency distribution. Data analysis was conducted using Statistical Package for the Social Sciences. Out of total children under 3 years who presented to the outpatient department, 46 (0.31%) at 95% Confidence Interval (0.30-0.32) had primary congenital glaucoma. Among them, 30 children (65.2%) had bilateral involvement. Mean intraocular pressure was 42.40±8.15mm Hg. The mean age of initial presentation, horizontal corneal diameter, and axial length were 12.07±8.9 months, 12.95±1mm, and 23.89±1.7mm respectively. Consanguinity was observed in 12 (26%) children. From the study, we conclude that there was a low prevalence of primary congenital glaucoma among children under 3 years of age who presented to the outpatient department in a tertiary care hospital.

Effect Of Trabeculectomy On Ocular Biometry And Refractive Errors In Pediatric Glaucoma

Background: Pediatric glaucoma triggers refractive errors by modifying the biometry of the eye. This study was conducted with the objective of estimating the short-term biometric and refractive changes prior to and post trabeculectomy in pediatric glaucoma. Material and Methods: A 12-month, descriptive, cross-sectional study was carried out from January to December 2019, using patients operated on for pediatric glaucoma. Pre- and post-operative biometric and refraction measurements were noted. Visual acuity, axial length, corneal diameter and refraction were obtained. All ethical requirements (anonymity, free, informed, and continuous consent) were satisfied. Data analysis was done using SPSS 20.0. Results: In the present study, 47 eyes of 27 patients were surgically operated upon, from January 2019 to December 2019 at CHU-IOTA. The predominant sex was male (17 patients) at 63%, giving a sex ratio (M / F) of 1.7. The mean age was 5.04 ± 4.24. Preoperatively, the mean corneal diameter, and D90 were respectively 13.83 ± 1.51 and 12.55 ± 0.99. Preoperatively, the mean axial length, and D90, were 23.87 ± 1.29 and 22.28 ± 1.07, respectively. Preoperatively and at three month, the mean myopia (n = 36), were respectively -3.13 ± 1.83 and -1.59 ± 0.97. The mean preoperative astigmatism (n = 47) and D90 were respectively, -1.59 ± 0.77 and -1.23 ± 0.57. A statistically significant relationship (p <0.05) was found to exist between the preoperative and postoperative data of the axial length, corneal diameter, and refractive errors. Conclusions: Trabeculectomy significantly exerts a short-term positive impact on the biometrics and refraction by modifying the initial measurements and diopters.

Evaluating target intraocular pressures in primary congenital glaucoma.

Purpose:The aim of this study was to evaluate long-term intraocular pressures that provide stabilization/reversal of glaucomatous neuropathy after surgery in primary congenital glaucoma (PCG).Methods:Prospective evaluation of consecutive PCG patients who underwent trabeculectomy-trabeculotomy and followed up for ≥2 years. Records of regularly performed examination under anesthesia were maintained to ascertain intraocular pressure, (IOP), fundus, refraction and corneal diameter. Outcomes – Primary: cup: disc ratio and intraocular pressure, Secondary: corneal changes and refractive errorResults:A total of 174 eyes of 108 children with PCG had a preoperative IOP of 22.44 ± 9.5 mm Hg. Postoperative review IOP was 11.8 ± 4.5 mm Hg, cup-disc-ratio was 0.52 ± 0.23 and corneal diameter was 12.75 ± 0.9 mm. Primary outcomes: Linear regression analysis showed a significant positive correlation of review IOP with cup disc ratio, P = 0.004. 67.9%, of eyes at a review IOP range of 6-12 mm Hg showed reversal, 14.1%, were stable, at 6-15 mm Hg, while 3.84% showed an increase in cup: disc ratio 16-22 mm Hg. Patients operated before 6 months of age had a significantly smaller final cup-disc ratio, P = 0.0013. Patients with a final cup: disc ratio of >0.9 were significantly older at surgery, P < 0.001. Secondary outcomes: There was a positive correlation of final myopia with review IOP on linear regression analysis, P = 0.012. The final spherical error in eyes having cup disc ratio of ≤ 0.5 was –0.96 ± 4.5 diopters, as against -3.45 ± 7.7 diopters in eyes having cup-disc ratio of 0.6-0.8 and -3.8 ± 6.9 diopters in eyes with cup disc ratio of ≥0.9, P = 0.015. There was no significant change in corneal diameter.Conclusion:Patients operated after 6 months of age had a larger final cup: disc ratio, while postoperative review intraocular pressures over 2 years of at least ≤15 mm Hg in primary congenital glaucoma eyes, commonly lead to reversal/stability of the neuropathy, and a lower incidence and degree of myopia.

Evaluation of Primary Pterygia on Basis of the Loss of Vertical Length of Plica Semilunaris.

PurposeTo propose a new grading system for primary pterygia based on the morphological loss of vertical length of plica semilunaris (LPS).MethodsWe included 50 eyes from 41 patients with primary pterygium. LPS was defined and quantified as the ratio of the length of loss of the normal vertical morphology at plica semilunaris to the vertical corneal diameter using anterior-segment photographs. Grades of tear metalloproteinase 9 (MMP-9) expression by point-of-care immunoassay, which is a well-known biomarker for inflammation, was correlated with the extent of LPS (%) of pterygia. Then, LPS was paralleled with the pre-established grading systems on the basis of tissue translucency (i.e., T grade) and vascularity (i.e., V grade) of the pterygium body.ResultsMMP-9 grades was 2.39 ± 1.12 in the group with LPS ≥50% and was 1.56 ± 1.12 in the group with LPS <50% (P = 0.016). In a linear regression, the extent of LPS was positively correlated with MMP-9 grades (r = 0.315, P = 0.026). MMP-9 expression did not differ between T grades or V grades. The extents of LPS were well correlated positively with both T grades (r = 0.495 and P < 0.001) and V grades (r = 0.344 and P = 0.015).ConclusionsWe devised a new grading system using LPS on the basis of morphological loss of the normal vertical plica semilunaris in primary pterygia. The extent of LPS correlated well with T grades and V grades and also reflected the expression of MMP-9 in tears.Translational RelevanceThe new clinical LPS grading system reflects severity and MMP-9 expression in tears in primary pterygia.

Comparison of IOL-Master 700 and IOL-Master 500 biometers in ocular biological parameters of adolescents.

To compare the differences and consistency of IOL-Master 700 biometers applying swept optical coherence tomography with the conventional IOL-Master 500 applying partial coherence interference in terms of the ocular biological parameters in adolescents with ametropia. A total of 110 adolescents (110 eyes) with ametropia were collected, including 55 males and 55 females; age 10.69±2.81y. Ocular biological measurements were taken by IOL-Master 700 and IOL-Master 500 respectively to obtain biological parameters including axial length (AL), mean corneal anterior surface keratometry (Km), anterior chamber depth (ACD), and horizontal corneal diameter (WTW). Paired t-test was used to compare the differences between the two instruments. The intra-group correlation coefficient (ICC) and the Bland-Altman analysis were used to evaluate the consistency of parameter measurements between the two instruments for the four biological parameters. Statistical analysis showed that there was no significant difference in the Km value measured by IOL-Master 700 and IOL-Master 500 (t=-1.644, P=0.116). The average differences of the AL, ACD, and WTW distances between the two instruments are 0.028, 0.101 and 0.064 mm respectively, and the differences are statistically significant (t=2.644, 12.505, 3.911, P<0.001). The consistency study results indicated high correlation in the measurement of AL, Km, ACD and WTW between the two instruments (ICC=0.994, 0.873, 0.927, 0.912). The novel biometric instrument IOL-Master 700 makes no difference with IOL-Master 500 in the measurement of Km. There are some differences in the values of AL, ACD, and WTW. However, the two instruments show good consistency in these four biological measurements. The measured values of Km are interchangeable between the instruments. These two types of biometrics can be used as mutual reference in consideration of that the differences in AL, ACD, and WTW measurements are not sufficient to produce clinically meaningful differences.

Megalocornea, anterior megalophthalmos, keratoglobus and associated anterior segment disorders: A review.

Megalocornea and anterior megalophthalmos (megalocornea spectrum) disorders are typically defined by corneal diameter > 12.5 mm in the absence of elevated intraocular pressure. Clinical features overlap with keratoglobus but are distinct from buphthalmos and severe (globus) keratoconus. Megalocornea spectrum disorders and keratoglobus are primarily congenital disorders, often with syndromic associations; both can present with large and thin corneas, creating difficulty in diagnosis, however, only keratoglobus is typically progressive. Molecular genetics provide significant insight into underlying aetiologies. Nonetheless, careful clinical assessment remains intrinsic to diagnosis. Surgical management can be challenging due to the enlarged ciliary ring and weakened zonules in megalocornea spectrum disorders and the extreme corneal thinning of keratoglobus. In this review, the established literature on measurement of corneal diameter, diagnosis of megalocornea, anterior megalophthalmos and keratoglobus, differentiation from severe keratoconus, recent molecular genetics research and key surgical modalities in the management of these rare disorders are outlined and discussed.

Comparison of ocular axis and corneal diameter between entropion and non-entropion eyes in children with congenital glaucoma.

BACKGROUNDChildren with congenital glaucoma are often accompanied by acquired epiblepharon in the lower eyelid, which causes entropion of the lower eyelid and damages the cornea.AIMTo infer the possible causes of lower eyelid entropion by comparing the difference of ocular axis and corneal diameter between inverted and non-inverted ciliary eyes in children with congenital glaucoma.METHODSA total of 15 patients (11 males and 4 females) diagnosed with congenital glaucoma between July 2016 and January 2019 at Tongren Hospital were included. Five patients had bilateral glaucoma, and ten had unilateral glaucoma. Each patient had only one eye with lower eyelid entropion which is associated with congenital glaucoma. All the patients had no entropion in another eye. The clinical data were collected. Main outcome measures were the ocular axis and corneal diameter.RESULTSThe average age of the 15 patients was 1.85 ± 0.49 years. Paired t-test showed that the average ocular axis of congenital glaucoma eyes with lower eyelid entropion (24.86 ± 3.44 mm) was significantly longer than that of congenital glaucoma eyes without lower eyelid entropion (20.79 ± 1.34 mm; P < 0.001). The average corneal diameter of congenital glaucoma eyes with lower eyelid entropion (13.61 ± 0.88 mm) was also significantly greater than that of congenital glaucoma eyes without lower eyelid entropion (11.63 ± 0.48; P < 0.001).CONCLUSIONThe rapid growth of the ocular axis and corneal diameter may be the main cause of congenital glaucoma with acquired lower eyelid entropion. Therefore, children with poor control of intraocular pressure and excessive growth of ocular axis and corneal diameter must be observed for the existence of acquired epiblepharon.

Intraobserver Repeatability of Tomographic, Pachymetric, and Anatomical Measurements in Healthy Eyes Using a New Swept-Source Optical Coherence Topographer.

The purpose of this study was to evaluate the intraobserver repeatability of several corneal parameters in healthy eyes using a new swept-source optical coherence topographer. Fifty right eyes of 50 subjects were enrolled in this study. A single examiner performed 3 consecutive measurements using the Anterion swept-source optical coherence tomography. The following corneal parameters were evaluated: average keratometry (K), steep K, flat K, astigmatism, best fit sphere, and maximum keratometry on the anterior and posterior surfaces at 3 mm, average K, steep K, flat K, and astigmatism in the total corneal power map at 3 mm, central corneal thickness and thinnest point thickness in the pachymetric map, and corneal diameter. To assess the repeatability of the measurements, we calculated the following indexes: intrasubject SD (Sw), coefficient of variation, coefficient of repeatability, and intraclass correlation coefficient (ICC). High repeatability was reported for all the evaluated corneal parameters, with Sw values lower than 0.027, coefficient of variation values lower than 0.066%, and coefficient of repeatability values lower than 0.187. ICC values showed a high correlation between measurements in all cases, being the lowest value for the astigmatism of the anterior surface (ICC = 0.92); for the rest, ICC values were larger than 0.98. Finally, we have not found statistically significant differences between repeated measurements (P > 0.05). The anterior segment measurements provided by the Anterion swept-source optical coherence tomography device show high intraobserver repeatability in healthy eyes.

To evaluate effect of intraocular pressure control on central corneal thickness, horizontal corneal diameter and axial length in primary congenital glaucoma

To evaluate the effect of intraocular pressure (IOP) on central corneal thickness (CCT), horizontal corneal diameter (HCD), axial length (AL) in patients with primary congenital glaucoma (PCG) after antiglaucoma surgery. In this hospital based interventional study 36 patients (66 eyes) of PCG who underwent antiglaucoma surgery were included in the study. For each patient visual acuity, anterior and posterior segment examination, IOP, AL, CCT, HCD and refraction (in clear media) were recorded pre and post operatively (3 weeks, 3 months, 6 months). B scan ultrasonography was done to measure AL and to rule out posterior segment pathology. Surgery was performed by a glaucoma expert (by a single surgeon). Bilateral involvement was present in 83.33% with the most common symptom being photophobia and watering (30.56% each). The mean IOP, CCT, HCD, VCD and AL before surgery were 26.88+/-2.78 mmHg, 614.38+/-89.41 µ, 14.41+/-1.26mm, 13.19+/-1.46mm and 24.78+/-2.21mm and at 6 months were 13.85+/-1.93 mmHg, 548.56+/-63.13 µ, 14.62+/-0.49 mm, 13.34+/-1.10 mm and 25.73+/-1.36mm respectively. 59.1% of the patients had corneal clearing at 6 months. Control of IOP affects various parameters of eye like CCT, HCD and AL. Early surgery is the definitive line of management for controlling IOP in PCG patients.

Comparison of viscocanalostomy plus suture-assisted near-360-degree trabeculotomy and viscocanalostomy plus rigid probe trabeculotomy inprimary congenital glaucoma.

To compare the efficacy and safety of viscocanalostomy plus near-360-degree suture trabeculotomy (VST) with viscocanalostomy plus rigid probe trabeculotomy (VT) in treating primary congenital glaucoma (PCG) over a one-year follow-up. This consecutive retrospective study included patients with PCG confirmed within 3 years of age from March 2017 to October 2019. Efficacy was evaluated by comparing the postoperative intraocular pressure (IOP) curve and the success rate at one year after surgery. Safety was assessed by comparing the postoperative complications. The number of anti-glaucoma agents, horizontal corneal diameter (HCD) and cup-to-disc ratio (C/D) of the two surgical methods were also compared. Data of 90 eyes from 61 patients were analysed. The baseline parameters of the two groups were similar. The IOP at 12 months after surgery in the VST group was 12.7 ± 4.8 mmHg, while that in the VT group was 15.8 ± 6.5 mmHg. The IOP at 6, 9 and 12 months postoperatively in the VST group was significantly lower than in the VT group (p < 0.05). Viscocanalostomy plus near-360-degree suture trabeculotomy (VST) remained a significant favourable factor for complete one-year success (93.6% versus 74.4%, p = 0.005) but not qualified one-year success (97.9% versus 88.4%, p = 0.06). The number of anti-glaucoma agents, HCD and C/D were reduced in both groups. Postoperative complications were not significantly different between the two groups. In children with PCG, VST provides a more durable IOP control than VT over the one-year follow-up, with a similar safety profile.

Trabeculectomy with Ologen combined with Mitomycin-C for the management of Primary Congenital Glaucoma

Background: Ologen is a collagen matrix designed to promote wound healing with minimal scarring. It has been used to create a prominent and healthy vascular bleb following trabeculectomy.Aim: The purpose of this study is to evaluate the adjunctive use of Ologen with mitomycin-C augmented trabeculectomy in eyes with primary congenital glaucoma.Patients and Methods: Ologen was placed in the subconjunctival space and under the scleral flap in 25 eyes of 21 patients with primary congenital glaucoma who underwent trabeculectomy with Mitomycin-C. Patients were examined preoperatively and in the 1st week, 1st, 3rd, 6th and 12th months after surgery. Examination included measurements of the intraocular pressure, corneal diameter, bleb evaluation, and fundus examination. Ultrasound biomicroscopy of the bleb was done at the last follow-up visit.Results: The mean age of the patients was 6.6 ± 2.95 months. Mean preoperative IOP was 22.56 ± 0.83 mmHg and the mean final postoperative IOP was 15.52 ± 3.54 mmHg. Complete success (IOP

Risk Factor for Transient Hyperopic Refractive Outcome at Acute Postoperative Period After Panoptix Intraocular Lens Implantation.

PurposeTo evaluate transient hyperopic refractive outcomes after Acrysof IQ Panoptix TFNT intraocular lens (IOL) implantation and risk factors for transient hyperopia.MethodsThis was a retrospective case review conducted from July 5, 2019, to February 28, 2020, of 203 eyes from 203 patients. The spherical equivalent (SE) on postoperative day 1, week 1, month 1, month 2, and month 6 was evaluated, and the difference between SE (dSE) on postoperative day 1 and month 6 was calculated. Ocular parameters that were associated with a high dSE were evaluated.ResultsThis study evaluated 203 eyes from 203 patients (mean age ± SD, 59.14 ± 5.78 years; 129 women [63.5%]). The dSE ± SD was 0.07 ± 0.30 D, 0.14 ± 0.34 D, 0.12 ± 0.35 D, and 0.08 ± 0.35 D for postoperative week 1, month 1, month 2, and month 6, respectively. Univariate analysis revealed that the anterior chamber depth and white-to-white (WTW) corneal diameter were associated with a larger dSE (P = 0.048 and P = 0.03, respectively). Multivariate analysis showed that the WTW diameter was independently associated with the large amount of dSE at 6 months (r = –0.162; P = 0.03).ConclusionThe results of this study suggest that a smaller WTW corneal diameter was associated with a large dSE between postoperative day 1 and postoperative month 6.

Correlation of Ocular Biometric Parameters and Macular Ganglion Cell Layer in Normal Eyes

ABSTRACT Purpose To determine the association between ocular biometric parameters and macular ganglion cell layer (MGCL) thickness in normal eyes. Methods This observational cohort study was conducted with 76 eyes of 76 healthy subjects. Keratometry, pachymetry, corneal volume, iridocorneal angle were measured with Sirius (CSO, Florence, Italy); axial length, anterior chamber depth, anterior chamber volume, corneal diameter were measured with IOL Master (Carl Zeiss Meditec, Dublin, California). For all participants, serial horizontal Spectralis Domain Optical Coherence Tomography (SD-OCT, Heidelberg Engineering, GmbH, Dossenheim, Germany) scans of the macula and peripapillary retinal nerve fiber layer (RNFL) analysis were obtained using SD-OCT. The relationship between numerical variables was given by Pearson correlation coefficient. Results The mean age of the subjects was 36.3 ± 11.9 years (between 19 and 70 y). Fifty-one patients were female (67.1%) and twenty-five patients were male (32.9%). MGCL was found to be correlated with anterior chamber depth, anterior chamber volume, iridocorneal angle, axial length and white to white (p = .015 r = 0.594, p = .002 r = 0.365, p = .013 r = 0.299, p = .004 r = 0.335, p = .013 r = 0.289, respectively). In addition, MGCL was correlated positively with the mean global and superotemporal RNFL (p ≤ 0.005). However, neither central corneal thickness nor keratometry values were found to be correlated with MGCL. Conclusion The results of this study showed that MGCL thickness is affected by ocular biometric parameters. Therefore, these parameters should be taken into consideration when interpreting MGCL thickness measurements in the diagnosis of glaucoma.

Newer insights into the clinical profile of posterior lenticonus in children and its surgical, visual, refractive outcomes.

To analyze the clinical profile of patients with posterior lenticonus and their surgical, visual, and refractive outcomes. Retrospective interventional case series of 84 eyes of 63 patients with posterior lenticonus. The incidence of posterior lenticonus was 3.98% during a study period of 5 years. One-third of cases had bilateral posterior lenticonus. The mean age was 4.78 ± 4.28 years (unilateral cases were significantly older than bilateral, P = 0.0001). Males were 54%. Mean axial length and keratometry were 21.49 mm and 44.88 D, respectively. Eyes with the bilateral disease were significantly shorter (axial length, P = 0.0012) and smaller (horizontal corneal diameter, P < 0.0001) compared to those with unilateral disease. While 88% were pseudophakic; 12% were aphakic. The posterior capsular defect was noted intraoperatively in 44%. Sixty-eight percent of eyes had a pre-operative diagnosis of posterior lenticonus, 32% were diagnosed intraoperatively. The mean follow-up period was 1.3 years. Best-corrected visual acuity (BCVA) at 6 months was fair to poor in two-third of patients (median 20/100). The mean ± SD visual acuity (LogMAR) and spherical equivalence for unilateral and bilateral cases were 0.70 ± 0.27, 0.67 ± 0.26D (p = 0.57) and 2.04 ± 2.74, 5.15 ± 3.73D (p = 0.0001), respectively. Visual outcomes were better in children who are aged 2 years or more (P = 0.0056). Eight percent needed a second surgery. We report a higher prevalence of bilateral posterior lenticonus in this cohort. The clinical profile of bilateral disease differs from unilateral disease. The diagnosis is not always clinical. In the bag, intra-ocular lens (IOL) implantation is possible in the majority. The visual outcomes remain fair to poor, possibly due to late presentation and the presence of dense refractory amblyopia. The manuscript consists of the largest series of posterior lenticonus to date. It provides the prevalence of posterior lenticonus along with characteristics difference between unilateral and bilateral cases of posterior lenticonus. Newer insights in terms of diagnostics, pre-operative pick-up rate, how to improve, visual and refractive outcomes of unilateral and bilateral cases are described.

Influence of corneal shape parameters on corneal deformation responses measured with a Scheimpflug camera.

To investigate the effect of corneal shape parameters on corneal deformation responses measured with a Scheimpflug camera. A total of 241 eyes of 241 participants were enrolled in this study. The anterior and posterior corneal curvature radii (CCR), anterior and posterior corneal Q-values, and corneal diameters of the participants were measured using the Pentacam HR. A total of 17 corneal deformation parameters including time, velocity, deflection amplitude, length, and area during ingoing applanation, highest concavity, and outgoing applanation were recorded by corneal visualization using Scheimpflug technology (Corvis ST). The effect of corneal shape parameters on corneal deformation responses was evaluated using multivariate regression models. Multivariate regression analyses showed that six, five, four, and three corneal deformation parameters were significantly correlated with anterior CCR, posterior CCR, anterior Q-value, and posterior Q-value, respectively. Steeper anterior corneal curvature was associated with faster velocity during ingoing applanation and greater deformation during outgoing applanation. Steeper posterior corneal curvature was correlated with faster velocity during outgoing applanation and greater deformation during ingoing applanation. Eyes that had steeper corneal curvatures were associated with less stiff corneas. More negative anterior Q-value corresponded with faster velocity and greater deformation during ingoing applanation. Eyes that had more prolate posterior corneal surfaces showed more resistance to corneal deformation at the highest concavity. However, corneal diameter was not selected in any corneal deformation parameters models. Corneal deformation response is significantly influenced by anterior and posterior corneal curvature and corneal asphericity, but not corneal diameter.

Comparison of Horizontal Corneal Diameter Measurements Using Orbscan IIz, OPD Scan III, and IOLMaster 700.

To compare three automated devices for measuring the horizontal corneal diameter (white to white [WTW]). In 65 eyes of 38 patients, the WTW distance was measured independently by three examiners using the following techniques: Orbscan IIz tomography system (Bausch & Lomb), IOLMaster 700 (Carl Zeiss Meditec), and OPD Scan III (NIDEK). We tested for systematic differences in measurements and estimated the limits of agreement (LoA) using linear mixed-effects models. The mean WTW distance was 11.8±0.40 mm with Orbscan IIz, 12.1±0.5 mm with IOLMaster 700 and 12.0±0.4 mm with OPD Scan III. The mean difference between IOLMaster 700 and Orbscan IIz was 0.33 (95% CI, 0.28 to 0.38; P<0.001), between OPD Scan III and Orbscan IIz was 0.24 mm (95% CI, 0.21 to 0.28; P<0.001), and between IOL Master 700 and OPD Scan III was 0.09 (95% CI, 0.05 to 0.12; P<0.001). The 95% LoA for Orbscan IIz versus IOLMaster 700 was -0.69 to 0.03 mm, Orbscan IIz versus OPD Scan III was -0.52 to -0.03 mm, and OPD versus IOLMaster 700 was -0.39 to 0.22 mm. The data suggest that these devices are not interchangeable for usual clinical practice. Adjustments based on mean differences were not enough to compensate for interinstrument discrepancy in WTW measurements.

Distribution of ocular biometric parameters and optimal model of anterior chamber depth regression in 28,709 adult cataract patients in China using swept\u2010source optical biometry

BackgroundThe purpose of this study was to evaluate the ocular biometric parameters in adult cataract patients from China and create an anterior chamber depth (ACD) regression model.MethodsThe ocular biometric records of 28,709 right eyes of cataract surgery candidates who were treated at Aier Eye Hospitals in nine cities from 2018 to 2019 were retrospectively analyzed. All measurements were taken with IOLMaster 700. We included patients who were at least 40 years old and were diagnosed with cataract.ResultsThe mean age of the patients was 68.6 ± 11.0 years. The mean values recorded were as follows: axial length (AL), 24.17 ± 2.47 mm; mean keratometry (Km) value, 44.26 ± 1.70 D; corneal astigmatism (CA), 1.06 ± 0.96 D; ACD, 3.02 ± 0.45 mm; lens thickness (LT), 4.52 ± 0.45 mm; central corneal thickness (CCT), 0.534 ± 0.04 mm; and white to white (WTW) corneal diameter, 11.64 ± 0.46 mm. ACD correlated positively with AL (Spearman coefficient, 0.544) and WTW (0.300), but negatively with LT (-0.660) and age (-0.285) (all P < 0.01). In the multivariate regression analysis of ACD, which included LT, AL, WTW, sex, Km, CCT, and age, there was a reasonable prediction with adjusted R2 = 0.641.ConclusionsCataract patients with longer AL and wider WTW have deeper ACD. With increasing age and lens thickening ACD becomes shallower. Based on the standardized coefficients of ACD multivariate regression analysis from the study, LT is the main factor that affects ACD, and is followed by AL.