Calculation of tunnel incision parameters during phacoemulsification in patients with previous anterior radial keratotomy

Background. The purpose was the choice of the type of tunnel incision on the basis of mathematical calculations in cataract patients with a previous anterior radial keratotomy. Materials and methods. During the calculations, the formula for the chord length of a circle was used: L = 2R · sin(α/2), where R is the radius of the cornea, α is the angle (in degrees) between the two corneal incisions. The chord length was measured on the limbus (upper edge of the tunnel incision) and 2 mm from the limbus (lower edge of the tunnel incision). The chord 2 mm from the limbus is more important because the distance between kerato­tomy incisions at this site is smaller. From 0.4 to 1.0 mm must be added to the width of the knife blade, depending on the type of postoperative corneal healing, which will be the key to crossing the incisions. Results. The most common knives are those 2.2 mm long with a tunnel length of 2 mm. Therefore, we perform calculations based on this knife in patients with 8 and 12 keratotomy incisions and a corneal diameter of 12 mm vertically and 11 mm horizontally. In patients with 8 keratotomy incisions, a 2.2 mm knife can be used for a corneal tunnel incision, and in patients with 16 incisions, it is impossible to use a corneal tunnel. Conclusions. In cataract patients who have previously undergone anterior radial keratotomy, a special approach is needed to the choice of tunnel incision. The choice of access depends on the diameter of the cornea, the number of keratotomy incisions and the width of the knife and is calculated using the formula for the chord length of a circle.

Congenital Cataract Surgery: A Retrospective Analysis of 62 Patients in a Developing Country

Purpose. This study was aimed at describing our experience in congenital cataract surgery in a developing Country. Methods. A retrospective study was conducted in Amman, Jordan. The patients who were diagnosed with congenital cataract and underwent the surgery were included in the study. It was decided to use an intraocular lens if the corneal diameter was more than 10 millimeters. Results. The findings revealed that around 13 of the patients did not have any visual axis opacification, indicating that they were aphakic. Visual axis opacification was seen in 8 out of the total sample of participants. Eleven patients with obvious opacification of the visual axis were found to be pseudophakic after at least two procedures and were thus cleared. It was necessary to do a second surgery to rectify the visual axis opacification induced by pseudophakia, which was putting the patient’s ability to recuperate at danger. Three of them (or 12 percent) exhibited visual axis opacification, which is a rare occurrence. The intraocular lenses used in the remaining 24 patients were constructed of hydrophilic plastic. Conclusion. Patients are less prone to have visual axis opacification while implanted by hydrophobic intraocular lenses is something they should consider.

Factors impacting cumulative dissipated energy levels and postoperative visual acuity outcome in cataract surgery

Purpose To determine factors impacting cumulative dissipated energy (CDE) and postoperative best-corrected visual acuity (BCVA) in phacoemulsification. Design Review of 1102 cases at University of California, San Francisco (UCSF) and at Zhongshan Ophthalmic Center (ZOC), China. Subjects Patients who underwent cataract surgery at UCSF 03/2014–03/2019 and at ZOC 10/2018–05/2019. Methods Patient demographics, medical history, routine ocular examination, and surgical information, including disassembly method, complications, and surgeon training level were recorded. Univariable and multivariable regression models were used to determine factors associated with CDE and good postoperative BCVA (20/40 or better) at 1 month. Outcome measures CDE, postoperative BCVA. Results In multivariable analysis, patient age at time of surgery, diabetes, degree of nuclear sclerosis (NS), white-to-white corneal diameter, disassembly method, preoperative BCVA, surgeon training level, and surgical center were significantly associated with CDE. Log10CDE increased by 0.20–0.31 for patient age ≥ 70 years, by 0.07 if the patient had diabetes, by 0.12–0.41 for NS grade ≥ 2, by 0.48 per 10 mm increase in white-to-white corneal diameter, by 0.34–0.47 for disassembly method other than non-stop chop, by 0.16 per unit increase in preoperative logMAR BCVA, and by > 0.09 when phacoemulsification was performed by residents early in their training. Log10CDE was 0.33 higher at UCSF than ZOC. In multivariable analysis, worse baseline visual acuity and age above 90 years at time of surgery decreased the odds of good BCVA (OR = 0.26 per unit increase in preoperative logMAR BCVA; OR = 0.12 for age > 90); comorbid retinal issues decreased the odds of good postoperative BCVA (OR = 0.13–0.39); greater anterior chamber depth (ACD) or shorter axial length (AL), increased the odds of good postoperative outcome (OR = 2.64 per 1 mm increase ACD, OR = 0.84 per 1 mm increase AL). Conclusions Cataract grade determined by slit lamp exam and, for the first time, older patient age, were noted to be important predictors of high CDE. CDE was not a risk factor for postoperative BCVA measured at postoperative 1 month. When surgery was performed by trainees under supervision, lower training level was associated with higher CDE, but not with worse postoperative BCVA.

Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients

Purpose: To investigate the distribution of white-to-white (WTW) corneal diameter and anterior chamber depth (ACD) in Chinese myopia patients.Methods: This was a cross-sectional observational study conducted at five ophthalmic centers. Anterior segment biometry was performed in 7,893 eyes of the 7,893 myopic patients using Pentacam, and the WTW and ACD were recorded. The distribution patterns of WTW and ACD were evaluated and the correlation between WTW and ACD was analyzed statistically.Results: There were 4416 (55.95%) males and 3477 (44.05%) females. The age of the study population was 25.14 ± 5.41 years. Distribution of WTW was slightly positively skewed (Skewness = 0.0076, Kurtosis = 0.3944, KS P = 0.020) with a mean of 11.65 ± 0.38 mm and a 95% normal range of 10.91–12.39 mm. A significant difference in WTW was found among different myopia groups (P < 0.001). The ACD was normally distributed (Skewness = 0.899, Kurtosis = 0.027, KS P = 0.086). The mean ACD was 3.25 ± 0.26 mm and the 95% normal range of was 2.74–3.75 mm. A significant difference in ACD was also found among different myopia groups (P = 0.030). There was a significant correlation between WTW and ACD (r = 0.460, P < 0.001).Conclusions: In our study, 95% of the Chinese myopic patients had a WTW within 10.91–12.39 mm and an ACD within 2.74–3.75 mm. ACD and WTW were significantly different among different myopia, gender and age groups. WTW was positively correlated with ACD.

Progression in pediatric glaucoma: Lessons learnt from 8 years’ follow-up

Background: Surgical procedures are used as 1 of the main treatment modalities for pediatric glaucoma, even though progression may occur. In this study, we aimed to investigate the risk factors affecting the progression of pediatric glaucoma.Methods: In this retrospective cohort study, we reviewed the medical records of patients diagnosed with pediatric glaucoma between April 2009 and March 2017. Pediatric glaucoma patients who underwent regular follow-up for at least 1 year were included. Demographics, intraocular pressure (IOP), central corneal thickness (CCT), axial length (AL), cup-to-disc ratio (C/D ratio), corneal diameter, type of glaucoma, age at time ofdiagnosis, and age at surgery were recorded. Progression was defined as an increase in AL > 2 mm, C/D ratio > 0.2, or corneal diameter > 1 mm during 1 year of follow-up.Results: Eighty-three eyes from 46 patients were included: 37 eyes (45%) with primary congenital glaucoma (PCG), 46 eyes (55%) with secondary glaucoma, and 27 of these 83 eyes (32.5%) showed progression. Progression was comparable between eyes with PCG and secondary glaucoma (PCG, 22%; secondary glaucoma, 41%; P = 0.152). Age at the time of diagnosis and age at the time of the first surgery were significantly lower in the eyes with progression (P = 0.046 and 0.012, respectively). The mean ± standard deviation of surgeries in progressed versus non-progressed eyes was 1.88 ± 1.1 versus 1 ± 0.8 (P = 0.015). The frequency of comorbid systemic disease was significantly higher in patients with glaucoma progression (P = 0.043). The progressed and non-progressed eyes were comparable in terms of other demographic characteristics and ocular parameters (allP > 0.05).Conclusions: Pediatric glaucoma patients who were younger at the time of diagnosis and the first glaucoma surgery and those with comorbid systemic disease are at higher risk of glaucoma progression. These findings are useful for clinicians when counseling parents of children with pediatric glaucoma about disease outcomes. However, future prospective studies with larger sample sizes and longer follow-up periods are needed to confirm our findings.

Quantitative Interocular Comparison of Total Corneal Surface Area and Corneal Diameter in Patients With Highly Asymmetric Keratoconus.

Keratoconus is a progressive corneal disorder which is frequently asymmetric. The aetiology of keratoconus remains unclear, and the concept of keratoconus as an ectatic disorder has been challenged recently. We carried out a retrospective study in 160 eyes of 80 patients, to evaluate and compare interocular differences in corneal diameter and surface area in patients with unilateral/highly asymmetric keratoconus (UHAKC). Calculations were performed using raw topographic elevation data derived from topographic measurements using Orbscan II, and we extrapolated surface areas up to measured corneal diameter. We also evaluated inter-eye correlation, and correlation between corneal surface area, corneal diameter and keratoconus severity. Our results showed a statistically significant but not clinically important greater corneal diameter (12.14mm and 12.17 mm; p=0.04), and corneal surface area (paired t-test, p<0.0001; p=0.0009 respectively) in more affected eyes. Inter-eye comparison revealed corneal diameter, anterior chamber depth, and corneal surface area were strongly correlated between eyes. Corneal surface area remained strongly correlated, and Bland-Altman analysis also showed strong inter-ocular agreement. Our results show that in patients with UHAKC the interocular difference in corneal diameter and corneal surface area is clinically insignificant, and are consistent with a redistribution, rather than increase, of corneal surface area with keratoconus progression.

Psychosocial indicators of primary congenital glaucoma and filtering surgeries impacts on children and family’s quality of life

Purpose: To identify psychosocial indicators and evaluate the filtering surgeries impacts on quality of life (QOL) of children with primary congenital glaucoma (PCG) and their family. Methods: Parents of children with bilateral PCG who underwent filtering surgery were included. Data were collected through: (a) psychological inquiry to determine psychosocial indicators; (b) Children’s Visual Function Questionnaire (CVFQ). The associations between the CVFQ scores and visual acuity, intraocular pressure, optic disk cupping, horizontal corneal diameter, axial length, number of surgeries, and hypotensive eye drops were investigated. The statistical significance level was considered as p ⩽ 0.05. Results: The mean age of the nine mothers interviewed and their children (six boys and three girls) was 29 ± 5 years and 35 ± 18 months, respectively. The psychosocial indicators determined were: emotional impact of the diagnosis, disease knowledge, mother and family’s feelings on facing the surgical treatment, surgical result comprehension, treatment adherence, child's emotional and behavioral reactions, social support, and future expectations. In CVFQ analysis, QOL score was strongly associated with visual acuity ( r = −0.79; p = 0.01). Besides the treatment score was correlated to intraocular pressure ( r = −0.68; p < 0.05), optic disk cupping ( r = −0.85; p = 0.03), and corneal diameter ( r = −0.69; p = 0.02). Correlations were not found for number of surgeries and eye drops. Conclusions: This study confirmed the PCG surgical treatment impact on QOL and determined psychosocial indicators which may favor the suitable actions in psychological treatment and follow-up of the children and families.