Relationship between preoperative axial length and myopic shift over 3 years after congenital cataract surgery with primary intraocular lens implantation at the National Institute of Ophthalmology of Peru, 2007-2011

Postoperative myopic shift and visual acuity rehabilitation in patients with bilateral congenital cataracts

Background

This study aimed to explore the postoperative myopic shift and its relationship to visual acuity rehabilitation in patients with bilateral congenital cataracts (CCs).

Methods

Bilateral CC patients who underwent cataract extraction and primary intraocular lens implantations before 6 years old were included and divided into five groups according to surgical ages (<2, 2-3, 3-4, 4-5, and 5-6 years). The postoperative myopic shift rates, spherical equivalents (SEs), and the best corrected visual acuity (BCVA) were measured and analyzed.

Results

A total of 1,137 refractive measurements from 234 patients were included, with a mean follow-up period of 34 months. The postoperative mean SEs at each follow-up in the five groups were linearly fitted with a mean R2 = 0.93 ± 0.03, which showed a downtrend of SE with age (linear regression). Among patients with a follow-up of 4 years, the mean postoperative myopic shift rate was 0.84, 0.81, 0.68, 0.24, and 0.28 diopters per year (D/y) in the five age groups (from young to old), respectively. The BCVA of those with a surgical age of <2 years at the 4-year visit was 0.26 (LogMAR), and the mean postoperative myopic shift rate was 0.84 D/y. For patients with a surgical age of 2-6 years, a poorer BCVA at the 4-year visit was found in those with higher postoperative myopic shift rates (r = 0.974, p = 0.026, Pearson's correlation test).

Conclusion

Performing cataract surgery for patients before 2 years old and decreasing the postoperative myopic shift rates for those with a surgical age of 2-6 years may benefit visual acuity rehabilitation.

The impact of pre-operative axial length on myopic shift 3 years after congenital and developmental cataract surgery and intraocular lens implantation

Purpose

To investigate the impact of the pre-operative axial length (AL) on myopic shift (MS) 3 years after primary intraocular lens (IOL) implantation in congenital/developmental cataract patients.

Methods

A retrospective study of patients who underwent congenital/developmental cataract surgery and primary IOL implantation at age 2-3 years at EENT Hospital was conducted. All patients were followed up regularly for at least 3 years after surgery. Refractive outcomes, including spherical equivalent (SE) and MS, were collected at each follow-up.

Results

Forty eyes from 40 patients were included. The mean age at surgery was 2.56 ± 0.57 years old, and the mean follow-up time was 3.05 ± 0.22 years. Patients were divided into two groups: Group 1 included 20 patients with longer pre-operative ALs (≥22 mm), and Group 2 included 20 patients with average pre-operative ALs (<22 mm). By the last follow-up, the MS was 2.13 (0.38, 2.63) D in Group 1 and 3.88 (2.85, 5.72) D in Group 2. The post-operative MS in Group 2 was statistically greater than that in Group 1 at 3 years after surgery (P < 0.001).

Conclusion

In congenital/developmental cataract patients who underwent cataract extraction and primary IOL implantation at age 2-3 years, eyes with longer pre-operative ALs had a slower MS than those with average pre-operative ALs 3 years after surgery. This finding could have implications for the target refraction decision in congenital/developmental cataract surgery.

Accuracy of the SRK/T Formula in Pediatric Cataract Surgery

PURPOSE

Determining IOL power is an important step in achieving the desired postoperative refractive target, but this determination remains challenging, as currently the used formulas were developed using IOL power calculations derived from adults.

PATIENTS AND METHODS

This is a retrospective analytical study with the period of June 2018 to May 2019. All of the data were taken from medical records in referral tertiary eye hospital in Indonesia. All type of cataracts underwent uncomplicated surgeries and in-the-bag IOL implantation were included in this study, while aphakia, secondary IOL implantation, primary sulcus implantation, and history of ocular disorders were excluded. The data were analyzed using Wilcoxon sign-rank, paired t, and Kruskal-Wallis tests.

RESULTS

Sixty-seven patients (106 eyes) were found to meet the inclusion criteria, average age was 7.35 ± 4.61 years (1.00 to 17.00 years). Average targeted refraction was 1.69 ± 2.06 D (-0.38-+6.99 D), and spherical equivalent (actual postoperative refraction) was -0.90 ± 1.45 D (-4.38 to +2.75 D). There was statistically significant difference between preoperative targeted refraction and actual postoperative refraction (p < 0.001). Mean absolute prediction error (APE) in general was 1.34 ± 1.18 D, 1.22 ± 0.88 D (in short eyes), 1.52 ± 1.37 D (in moderate eyes), and 0.69 ± 0.52 D (in long eyes) (p = 0.202). Mean APE in age group <7 years old was 1.27 ± 1.18 D and ≥7 years-old was 1.42 ± 1.19 D (p = 0.429).

CONCLUSION

SRK/T formula is fairly accurate in calculating IOL power in pediatric cataract surgery. Mean APE in this study was within the range of accurate mean APE in pediatric patients despite differentiated axial length and age.

Deviations From Age-Adjusted Normative Biometry Measures in Children Undergoing Cataract Surgery: Implications for Postoperative Target Refraction and IOL Power Selection

PURPOSE

To evaluate whether pediatric eyes that deviate from age-adjusted normative biometry parameters predict variation in myopic shift after cataract surgery.

METHODS

This is a single institution longitudinal cohort study combining prospectively collected biometry data from normal eyes of children <10 years old with biometry data from eyes undergoing cataract surgery. Refractive data from patients with a minimum of 5 visits over ≥5 years of follow-up were used to calculate myopic shift and rate of refractive growth. Cataractous eyes that deviated from the middle quartiles of the age-adjusted normative values for axial length and keratometry were studied for variation in myopic shift and rate of refractive growth to 5 years and last follow-up visit. Multivariable analysis was performed to determine the association between myopic shift and rate of refractive growth and factors of age, sex, laterality, keratometry, axial length, intraocular lens power, and follow-up length.

RESULTS

Normative values were derived from 100 eyes; there were 162 eyes in the cataract group with a median follow-up of 9.6 years (interquartile range: 7.3-12.2 years). The mean myopic shift ranged from 5.5 D (interquartile range: 6.3-3.5 D) for 0- to 2-year-olds to 1.0 D (interquartile range: 1.5-0.6 D) for 8- to 10-year-olds. Multivariable analysis showed that more myopic shift was associated with younger age (P < .001), lower keratometry (P = .01), and male gender (P = .027); greater rate of refractive growth was only associated with lower keratometry measures (P = .001).

CONCLUSIONS

Age-based tables for intraocular lens power selection are useful, and modest adjustments can be considered for eyes with lower keratometry values than expected for age.

Efficacy of Toric Intraocular Lens and Prevention of Axis Misalignment by Optic Capture in Pediatric Cataract Surgery

PURPOSE

To compare the outcomes of intraocular lens (IOL) implantation using toric (T)-IOL and non-toric (N)-IOL in pediatric cataract patients with astigmatism, and to examine the effect of optic capture (OC) on the axis misalignment (AM) of the T-IOLs.

SETTING

Department of Ophthalmology, Kindai University Hospital, Osaka, Japan.

DESIGN

Interventional, comparative case study.

METHODS

Consecutive pediatric patients implanted with T-IOLs or N-IOLs were retrospectively reviewed. In the T-IOL group, the preoperative and postoperative corrected distance visual acuity (CDVA) and AM were compared in patients with and without OC.

RESULTS

The T-IOL group included 14 eyes of 11 patients, while the N-IOL group included 22 eyes of 15 patients. One year after surgery, the mean ocular cylinder (1.38 ± 0.80 D) was significantly smaller than the average corneal cylinder (3.33 ± 1.24 D) in the T-IOL group (P = .00012, Wilcoxon signed-rank test). The mean preoperative and 1-year postoperative CDVA (logMAR) were 0.57/0.003 (T-IOL) and 0.71/0.09 (N-IOL), respectively. The AM at 1 week and 1 year after surgery was 2.6° ± 3.7° and 4.4° ± 3.1° for the OC group, and 13.3° ± 8.8° and 18.5° ± 14.8°, for the non-OC group, respectively. The AM was significantly smaller in the OC group than that in non-OC group (P = .009, Mann-Whitney U test) at postoperative 1 week.

CONCLUSION

T-IOL implantation is effective in correcting astigmatism in pediatric cataract patients with astigmatism, and the OC technique is likely to achieve lower AM of the T-IOL.

Novel mutation of GJA8 in autosomal dominant congenital cataracts

Background

Congenital cataracts is the most common cause of childhood visual impairment and blindness worldwide. It is reported that about one quarter of congenital cataracts caused by genetic defects. Various gene mutations have been identified in hereditary cataracts so far. The purpose of the present study was to investigate the relationship between gap junction protein alpha 8 (GJA8) gene mutation and congenital cataract.

Methods

A pedigree with autosomal dominant congenital cataract was investigated and the peripheral venous blood was extracted from 18 family members. After the high-throughput targeted capture and whole exome sequencing for the proband, bioinformatics analysis was performed. By combining the proband clinical symptoms, candidate variations were eliminated which were significantly not consistent with the clinical phenotype. And disease-causing variant was identified.

Results

Gene sequencing revealed the heterozygous missense mutation in exon 2 of the GJA8 gene (c.178G>A), which co-segregated with the disease phenotype in the family and resulted in the substitution of glycine to serine at position 178 (p.G60S). This missense mutation was located in the hotspot mutation region, and might be harmful.

Conclusions

This study reports a novel disease-causing sequence variant in the gap junctional protein encoding genes causing autosomal dominant congenital cataract in the Chinese population, caused by the missense mutation of GJA8 (c.178G>A). Our data expand the spectrum of GJA8 variants and associated phenotypes, facilitate clinical diagnosis and support the presence of relationship between genetic basis and human disease.

Molecular genetics of congenital cataracts

Congenital cataracts, the most common cause of visual impairment and blindness in children worldwide, have diverse etiologies. According to statistics analysis, about one quarter of congenital cataracts caused by genetic defects. Various mutations of more than one hundred genes have been identified in hereditary cataracts so far. In this review, we briefly summarize recent developments about the genetics, molecular mechanisms, and treatments of congenital cataracts. The studies of these pathogenic mutations and molecular genetics is making it possible for us to comprehend the underlying mechanisms of cataractogenesis and providing new insights into the preventive, diagnostic and therapeutic approaches of cataracts.