Characteristics of rhegmatogenous retinal detachment after refractive surgery: comparison with myopic eyes with retinal detachment

Benefits and risks of orthokeratology treatment: a systematic review and meta-analysis

BACKGROUND

This meta-analysis reviews the evidence for the risks and benefits associated with orthokeratology (OK) treatment compared with other methods of myopia control in children and adults.

METHODS

A systematic search of Cochrane Central Register of Controlled Trials, Pubmed, Embase and Ovid was conducted from database inception to 22nd August 2021. Studies that reported on risks, visual and ocular biometric effects of OK in patients > 5 years of age with myopia (- 0.75 to - 6.00D) were included. Main outcomes are change in axial length and any adverse event.

RESULTS

Fourty-five papers were included in this systematic review and meta-analysis. The quality of data was variable and of moderate certainty, and selection bias likely skewed the results towards a relative benefit for OK. The rate of axial elongation in children was lower for OK treatment compared to other treatment modalities at one year (MD - 0.16 mm, 95% CI - 0.25 to - 0.07). Rate of change in axial length in children rebounded after OK discontinuation compared to participants who continued treatment (MD 0.10 mm, 95% CI 0.06 to 0.14). Adults and children wearing OK were up to 3.79 times more likely to experience an adverse event when compared with conventional contact lenses (OR 3.79, 95% CI 1.24 to ll.), though this evidence base is underdeveloped and requires additional well-designed studies for substantial conclusions to be drawn.

CONCLUSIONS

OK arrests myopia progression while in use, however, there remain unanswered questions about the optimal duration of treatment, discontinuation effects and long-term risk for adverse events.

Phakic intraocular lens explantation: a series of 175 surgeries

PURPOSE

The ideal timing for phakic intraocular lens (pIOL) explantation remains unknown. Our study aims to evaluate the indications for pIOL explantation, pIOL survival time, visual outcomes, and access endothelial cell loss (ECL) after explantation.

SETTING

Ophthalmology Department, Centro Hospitalar Universitário do Porto, Portugal. Design: Retrospective longitudinal study.

METHODS

Chart review was performed for all consecutive patients that underwent pIOL explantation from January 2010 to December 2019 in a single center.

RESULTS

This study included 175 eyes of 112 patients, 77% of which were female. Phakic IOL survival was 12.9 ± 4.8 [3.7 - 28.6] years and the follow-up period after explantation was 4.1 ± 3.0 [0.3 - 9.9] years. The most frequent causes for explantation were cataract formation (44.0%, n=77) and ECL (50.3%, n=88). During the follow-up period after explantation, mean ECL rate was 2.27 ± 9.32 %/year in the cataract group and -2.14 ± 10.24 %/year in the ECL group, reflecting a positive change in cell density in the latter. Eight eyes (4.6%) required a corneal transplant during the follow-up. Mean corrected distance visual acuity was 0.17 ± 0.24 logMAR at the last visit.

CONCLUSION

Our study demonstrates that pIOL explantation, after an average survival time of 13 years, is a safe procedure. The main causes for explantation were cataract formation and ECL. Most patients show a sustained improvement in visual acuity and endothelial cell density after pIOL explantation, and yet its timing should be ideal to avoid irreversible complications.

Factors associated with faster axial elongation after orthokeratology treatment

Background

To study the baseline factors that related to faster axial elongation after orthokeratology (OK) treatment and the characteristics of cases with axial length decrease in a group of myopia children.

Methods

This is a retrospective study. The records of 73 children who had wear OK lens for at least one year were reviewed. Only the data of right eyes were included. Baseline data included: age, gender, parental myopia, refractive error, corneal power, central corneal thickness, axial length and anterior chamber depth. Corneal power, central corneal thickness, anterior chamber depth and axial length after one-year of OK lens wear were also collected. The related factors affecting axial length change were analyzed. A comparison was made on the cases of axial length increase and axial length decrease.

Results

Of the 73 eyes, axial length increased by 0.18 ± 0.17 mm (P < 0.001) after one year of OK lens wear. Correlation analysis showed that one-year axial length change was negatively correlated with age and positively correlated with the parental myopia and baseline myopia. Stepwise multiple linear regression analysis showed that the factors associated with faster axial elongation were lower baseline myopic spherical equivalent (P = 0.018), higher parental myopia degree (P = 0.026), and younger age at the onset of lens wear. (P = 0.039). Nine eyes showed negative axial growth (−0.06 ± 0.04 mm), and had older initial age of lens wear, higher baseline myopic spherical equivalent, and lager baseline corneal power, when compared with cases of axial length increase.

Conclusions

Myopia children with lower baseline myopic spherical equivalent, younger initial age and higher parental myopia had faster axial elongation after orthokeratology treatment. More aggressive treatment should be considered. In children with slow axial elongation, OK lens wear may lead to negative axial growth. Whether there are reasons other than central corneal thinning and choroidal thickening needs further study.

Distribution of ocular biometry in young Chinese eyes: The Anyang University Students Eye Study

PURPOSE

To investigate the distribution of ocular biometric parameters and its association to refraction in university students in central China.

METHODS

Ocular biometric parameters including axial length (AL), central corneal thickness (CCT), keratometry power (K), anterior chamber depth (AQD) and lens thickness (LT) were measured by an optical biometry in a cohort of university students. Corneal radius of curvature (CR), lens position (LP), lens power (P_Bennett ), vitreous chamber depth (VCD) and AL to corneal radius ratio (AL/CR) were calculated. Cycloplegic refraction was measured using an autorefractor.

RESULTS

A total of 7650 undergraduate students participated in this study, with a mean age of 20.0 ± 1.4 years. The following ocular biometric parameters were measured: AL (24.78 ± 1.21 mm), CCT (539.83 ± 33.03 μm), AQD (3.23 ± 0.25 mm), LT (3.47 ± 0.18 mm), CR (7.79 ± 0.27 mm), LP (4.97 ± 0.23 mm), VCD (17.55 ± 1.15 mm), P_Bennett (25.00 ± 1.07 dioptres) and AL/CR (3.18 ± 0.15). Male subjects were found to have longer AL, thicker CCT, flatter CR, thinner lens, deeper AQD and VCD than female ones. Myopic subjects were found to have longer AL, thinner CCT, steeper CR, thinner and posterior lens, deeper AQD and VCD, lower P_Bennett and larger AL/CR than emmetropes and hyperopes. Spherical equivalent (SE) showed a negative correlation with AL/CR (r = -0.914), AL (r = -0.755) and VCD (r = -0.751).

CONCLUSIONS

This study provided a range of reference values for the main ocular biometric parameters in young adults and reported their distributions based on gender and refractive status. Our study indicates that SE has a strong correlation with AL/CR ratio, AL and VCD.

Myopic retinal changes screening: comparison of sensitivity and specificity among 15 combinations of ultrawide field scanning laser ophthalmoscopy images

AIMS

To investigate the evaluation indices (diagnostic test accuracy and agreement) of 15 combinations of ultrawide field scanning laser ophthalmoscopy (UWF SLO) images in myopic retinal changes (MRC) screening to determine the combination of imaging that yields the highest evaluation indices in screening MRC.

METHODS

This is a retrospective study of UWF SLO images obtained from myopes and were analyzed by two retinal specialists independently. 5-field UWF SLO images that included the posterior (B), superior (S), inferior (I), nasal (N) and temporal (T) regions were obtained for analysis and its results used as a reference standard. The evaluation indices of different combinations comprising of one to four fields of the retina were compared to determine the abilities of each combinations screen for MRC.

RESULTS

UWF SLO images obtained from 823 myopic patients (1646 eyes) were included for the study. Sensitivities ranged from 50.0% to 98.9% (95% confidence interval (CI), 43.8-99.7%); the combinations of B+S+I (97.3%; 95% CI, 94.4-98.8%), B+T+S+I (98.5%; 95% CI, 95.9-99.5%), and B+S+N+I (98.9%; 95% CI, 96.4-99.7%) ranked highest. Furthermore, the combinations of B+S+I, B+T+S+I and B+S+N+I also revealed the highest accuracy (97.7%; 95% CI, 95.1-100.0%, 98.6%; 95% CI, 96.7-100.0%, 98.8%; 95% CI, 96.9-100.0%) and agreement (Kappa = 0.968, 0.980 and 0.980). For the various combinations, specificities were all higher than 99.5% (95% CI, 99.3-100.0%).

CONCLUSION

In our study, screening combinations of B+S+I, B+T+S+I and B+S+N+I stand out with high-performing optimal evaluation indices. However, when time is limited, B+S+I may be more applicable in primary screening of MRC.

Incidence of Intraoperative and Early Postoperative Adverse Events in a Large Cohort of Consecutive Laser Vision Correction Treatments

PURPOSE

To evaluate the incidence of adverse events (AE) following laser vision correction.

DESIGN

Retrospective case series.

METHODS

Optical Express, UK. Patients/study population: patients who underwent laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) between July 1, 2014, and June 30, 2016. Intervention/observation procedures: all AEs recorded in the electronic medical record were extracted and retrospectively reviewed. The total incidence of AE and serious adverse events (SAE) was calculated. Loss of 2 or more lines of corrected distance visual acuity (CDVA) was calculated for the entire cohort of patients that attended a minimum of 3 months follow-up.

MAIN OUTCOME MEASURES

AEs; Preoperative and last available postoperative clinical data.

RESULTS

A total of 31,921 (61,833 eyes) were included in the study for LASIK and 5,016 (9,467 eyes) for PRK. The total number of AE was 850 for LASIK (occurring in 783 eyes of 657 patients; incidence of 1.3% or 1:79 eyes) and 227 for PRK (occurring in 218 eyes of 170 patients; incidence of 2.3% or 1:43 eyes). In the LASIK group, there were 287 SAEs (271 eyes of 226 patients; incidence of 0.4% or 1:228 eyes), and the number of SAEs in PRK group was 65 (65 eyes of 39 patients; incidence 0.7% or 1:146 eyes). Combining LASIK and PRK data, the loss of 2 or more lines of CDVA was recorded in 0.37% of eyes.

CONCLUSIONS

Contemporary LASIK and PRK are safe procedures with a low incidence of serious adverse events.

The Association between Macular Thickness and Axial Length in Myopic Eyes

Purpose

To investigate the relationship between macular thickness and axial length (AL) in myopic eyes.

Methods

We included 441 myopic eyes in this study and measured macular thickness at the fovea and in other macular regions, using optical coherence tomography. We got thickness difference indices (TDIs) which by definition are the values of thickness difference obtained by subtracting the foveal thickness from that of each macula sector to evaluate macular contour. We then analyzed the relationships between AL and foveal thickness and AL and the TDIs of each macular sector.

Results

In polynomial regression analyses, foveal thickness slope was relatively flat up to an AL of 25.5 mm and began to rise from 25.5-26.0 mm. The TDIs were also relatively flat up to AL of 25.5mm and started to show steepened negative slopes from around AL of 25.5 mm. When grouping myopia participants as high myopia or non-high myopia based on AL of 25.5mm, all macular indices of the high myopia group showed significant correlation with AL (all p values <0.01). But all indices of non-high myopia group had no significant correlation with AL.

Conclusions

Average macular thickness profiles showed that appreciable changes started at an AL of 25.5mm.

Peripheral retinal changes in highly myopic young Asian eyes

PURPOSE

To determine the type and prevalence of peripheral retinal changes and its relationship with axial length (AL) in a population of young Asian adult males.

METHODS

This was a cross-sectional study of male subjects aged between 19 and 25 years old. High myopes [spherical equivalent refraction, (SER) < -6.00 D] were recruited and underwent further ocular investigations including dilated retinal photography and binocular indirect ophthalmoscopy by two trained ophthalmologists. The frequency of peripheral retinal changes within high myopes was correlated with axial length and also compared with a group of emmetropes (SER between -0.50 D and +1.00 D).

RESULTS

A total of 593 high myopes and 156 emmetropes were recruited. White without pressure (WWOP; n = 458, 46.5%) and lattice degeneration (LD; n = 109, 14.6%) were the commonest findings, and their prevalence was significantly higher among high myopes (LD, 16.9% versus 5.8%; WWOP, 57.2% versus 5.8%; both p < 0.001). Among high myopes, temporal LD was more common (71%) and 35% had more than one area in the same eye. Increasing AL was associated with LD (odds ratio 1.28, p = 0.01) and retinal holes (odd's ratio 1.44, p = 0.02) on multivariate analysis.

CONCLUSION

White without pressure (WWOP) and LD were the commonest peripheral retinal changes. One-third of high myopes with LD had more than one area in the same eye. Increasing AL was associated with LD and retinal holes. Studies in older adults should be conducted to develop clinical guidelines for the management of high myopes.

Real-Time Intraocular Pressure Measurements in the Vitreous Chamber of Rabbit Eyes During Small Incision Lenticule Extraction (SMILE)

PURPOSE

To investigate real-time intraocular pressure (IOP) during small incision lenticule extraction (SMILE) in rabbit eyes for myopia correction.

METHODS

During SMILE, real-time IOP was measured in the vitreous cavity of rabbit eyes with an optic fiber pressure sensor (OFPS). Two groups (n = 6 for each) underwent surgery, one group for a -2.00 diopter (D) refractive spherical correction and the other for a -6.00 D correction.

RESULTS

During surgery, the IOP increased once the glass contact attached to the cornea (Pre-suction), and peaked 83.94 mmHg (SD ± 23.87 mmHg) for the -2.00 D group and 89.17 mmHg (SD ± 22.66 mmHg) for the -6.00 D group, both average values were less than 110 mmHg when suction was initiated to fix the glass contact onto the cornea (Suction on). It then fell to 74.81 mmHg (SD ± 20.64 mmHg) and 76.94 mmHg (SD ± 27.43 mmHg), respectively, and remained stable during lenticule creation (Cutting). After suction stopped (Suction off), IOP fell steeply. During lenticule separation/extraction, the change in IOP was 32.26 mmHg (SD ± 2.91 mmHg). Notably, the average duration of elevated IOP during the surgery was 166.05 s (no longer than 3 min).

CONCLUSIONS

The IOP fluctuations in the vitreous cavity using an OFPS in a rabbit model during SMILE showed that real-time IOP significantly was increased during Pre-suction, Suction on, Cutting, Suction off, and lenticule separation/extraction compared to baseline IOP, although, peaked at Suction on. Neither the degree of myopic correction nor central corneal thickness significantly affected these changes in IOP.

Influence of Overnight Orthokeratology on Corneal Surface Shape and Optical Quality

Purpose

To investigate the changes of corneal surface shape and optical quality during orthokeratology.

Methods

49 eyes of 26 patients (10.63 ± 2.02 years old) who underwent overnight orthokeratology for myopia were prospectively examined. The corneal surface shape parameters, including surface regularity index (SRI) and surface asymmetry index (SAI), were attained with an OPD-III SCAN. The higher-order aberrations and higher-order Strehl ratios were calculated under a 3 mm pupil diameter before orthokeratology, 1 month, 3 months, and 6 months after orthokeratology. A P value of less than 0.05 was statistically significant.

Results

Months after orthokeratology, SRI and SAI were both showing a significant increase in comparison with those before orthokeratology (P < 0.001). After orthokeratology, for a 3 mm pupil, the higher-order Strehl ratio presented a reduction of 0.217 μm (P < 0.001), and the higher-order aberration root mean square (HOA RMS) showed a mean increase of 0.100 μm (P < 0.001). There were significant increases in spherical aberration (P < 0.001) and coma (P = 0.044) after orthokeratology. Trefoil showed a slight reduction at month 6 after orthokeratology, but there was no statistical significance (P = 0.722).

Conclusion

Overnight orthokeratology for a correction of myopia resulted in a significant improvement in refractive error but increased corneal irregularity and ocular higher-order aberrations, especially in spherical aberration.

Distribution of axial length, anterior chamber depth, and corneal curvature in an aged population in South China

Background

Ocular biometry is important for preoperative assessment in cataract and anterior segment surgery. The purpose of this study was to investigate normative ocular biometric parameters and their associations in an older Chinese population.

Methods

This was a cross-sectional observational study. From 2013 to 2014, we recruited inhabitants aged 50 years or older in Guangzhou, China. Among 1,117 participants in the study, data from 1,015 phakic right eyes were used for analyses. Ocular parameters including axial length (AL), anterior chamber depth (ACD), and corneal curvature (K) were measured using an IOL Master.

Results

The mean AL, ACD, and K were 23.48 mm [95 % confidence interval (CI), 23.40–23.55], 3.03 mm (CI, 3.01–3.05), and 44.20 mm (CI, 44.11–44.29), respectively. A mean reduction in ACD with age was observed (P = 0.002) in male subjects but not in female subjects (P = 0.558). Male subjects had significantly longer ALs (23.68 mm versus 23.23 mm, P < 0.001), deeper ACDs (3.13 mm versus 2.95 mm, P < 0.001), and flatter Ks (43.85D versus 44.50 D, P < 0.001) than female subjects. Eyes with axial elongation had a flatter cornea (r = −0.437, P < 0.001) and a deeper anterior chamber (r = 0.652, p < 0.001). The ACD was correlated with K (r = −0.266, P < 0.001).

Conclusions

These data provide normative values for AL, ACD, and K using the IOL Master for a population in South China. The AL in this Chinese cohort was greater than that observed in the Singaporean Chinese but smaller than that observed in Malaysia and for Caucasians. The Chinese have a shallower ACD than some other racial groups. Age and sex were the most consistent predictors of ocular biometry in the older population from South China.