[Comparison of Toric intraocular lenses and corneal incisional procedures for correction of low and moderate astigmatism during cataract surgery: A meta-analysis]

Objective: To systematically compare the effects of Toric intraocular lens (IOL) implantation and corneal incisional procedures on the correction of astigmatism during cataract surgery. Methods: A peer-reviewed literature search was implemented in MEDLINE, EMBASE, EBSCO, ScienceDirect, Trip Database, Ovid, and the Chinese databases including CNKI and Wanfang Data. The inclusion criteria were randomized controlled trials (RCTs) that compared the Toric IOL implantation and the corneal incisional procedures to correct low and moderate astigmatism during cataract surgery. The mean difference (MD) and the relative risk were respectively used to describe the effect sizes of continuous data and nominal data with a confidence interval (CI) of 95%. The random effects model was applied to pool the data including postoperative uncorrected visual acuity, residual astigmatism and surgical complications by Review Manager 5.3. Results: A total of 12 RCTs were included in this study, including 330 eyes implanted with Toric IOLs and 336 eyes with non-Toric IOLs combined with corneal incisional procedures to correct astigmatism. According to the types of corneal incisions, the included RCTs were divided into three groups: limbal relaxing incision group, opposite clear corneal incision group, and astigmatic keratotomy group. Meta-analysis showed that postoperative logarithm of the minimum angle of resolution uncorrected visual acuity was significantly better in eyes implanted with Toric IOLs than those with corneal incisional procedures (MD, -0.05; 95% CI, -0.08 to -0.02; P<0.01), and the residual astigmatism was significantly lower in eyes implanted with Toric IOLs (MD, -0.33 D; 95% CI, -0.48 to -0.18 D; P<0.01). There was no significant difference in the risk of surgical complications between the Toric IOL implantation and the corneal incision correction for astigmatism (relative risk, 0.45; 95% CI, 0.07 to 2.95; P=0.40). Conclusions: The current evidence suggests that Toric IOL implantation is more effective in correcting astigmatism than corneal incisional procedures during cataract surgery and shows better postoperative visual acuity. However, they are similar in the risk of postoperative complications. (Chin J Ophthalmol, 2019, 55: 522-530).

[Clinical comparison analysis in surgically induced astigmatism of the total, anterior and posterior cornea after 2.2-mm versus 3.0-mm clear corneal incision cataract surgery]

Objective: To compare the surgical induced astigmatism(SIA) of the total, anterior and posterior cornea between eyes with 2.2-mm and 3.0-mm clear corneal incisions in phacoemulsification. Methods: A prospective double-blind randomized controlled study was conducted on 131 patients (131 eyes) with age-related cataract from October 2017 to June 2018. They were randomized according to the random number table. Sixty-nine patients received phacoemulsification through a 2.2-mm clear corneal incision at 140 degrees; 62 patients were recruited in the control group with a 3.0-mm clear corneal incision at the same position. Lens density was graded and compared between the groups preoperatively. Total corneal refractive power (TCRP), simulated keratometry (SimK) and posterior corneal astigmatism (PCA) (Apex, 4-mm zone) were recorded through the Pentacam preoperatively and at 1 week, 1 month and 3 months postoperatively. Corneal astigmatism was decomposed to vertical/horizontal (X) and oblique changes (Y) using the power vector analysis. Independent sample t test and matched t test were used for statistical analysis. Results: A total of 123 patients (123 eyes) completed 3 months of follow-up including 65 in the 2.2-mm group and 58 in the control group. The age of the two groups was (69±9) and (71±10) years old, and the lens density was (2.08±0.47) and (2.12±0.46) grades, respectively. Both the age and the lens density of the two groups were not statistically significant (both P>0.05). Preoperative TCRP, SimK and PCA were not statistically significant (all P>0.05). SIA was calculated using the vector analysis. Centroid SIA conducted from TCRP, SimK and PCA in the 2.2-mm group was -0.11 D@146°, -0.11 D@151° and -0.03 D@67°, respectively, at 3 months postoperatively. In the 3.0-mm group, it was -0.25 D@158°, -0.24 D@147° and -0.04 D@47°, respectively. Statistical significance was found between the two groups in the Y polar value of SIA of the anterior surface [(-0.10±0.30) vs.(-0.22±0.37) D, t=-2.133, P=0.035] and the SIA of the posterior surface [(0.24±0.16) vs. (0.19±0.12) D, t=2.009, P=0.047] at 3 months postoperatively. In the comparison of the SIA of TCRP and anterior surface, statistical significance was found in the absolute value of SIA at all the intervals in the 2.2-mm group [(0.87±0.80) vs. (0.58±0.48) D, (0.58±0.48) vs. (0.50±0.28)D, (0.57±0.37) vs. (0.47±0.28) D, t=5.102, 4.155, 3.877, all P<0.01] and at 1 week and 1 month in the 3.0-mm group [(0.82±0.57) vs. (0.58±0.41) D, (0.59±0.36) vs. (0.50±0.28) D, t=5.034, 3.919, both P<0.01]. X components of SIA(TCRP) and SIA(simk) were significantly different at 3 month postoperatively in 3.0-mm group (P<0.05). Y components of SIA(TCRP) and SIA(SimK) were significantly different at 1 week postoperatively in the 2.2-mm group[(-0.48±0.85) vs.(-0.24±0.42) D, P<0.01] and 3.0-mm group [(-0.58±0.66) vs. (-0.37±0.42) D, P<0.01]. Conclusions: Compared with the 3.0-mm incision, the 2.2-mm coaxial micro-incision cataract surgery has a lower and more stable SIA. The effect of a clear corneal incision in cataract surgery on the total cornea is more obvious than that on the anterior surface of the cornea. The difference is significant in the early stage and gradually decrease with time. (Chin J Ophthalmol, 2019, 55: 495-501).

[Several controversial issues in astigmatism correction in cataract surgery]

Cataract surgery has entered the era of refractive surgery, and patients have higher requirements for visual quality. Astigmatism correction in cataract surgery is increasingly valued, but the astigmatism correction results are not ideal, and the principles of corneal astigmatism correction are not well established. In this article, the issues including how to dialectically decide to treat the corneal astigmatism or not, how to choose the corneal astigmatism estimating method and the calculation formula for astigmatism correction, the range of corneal astigmatism suitable for applying multifocal intraocular lens, selection of intraoperative corneal astigmatism correction method, etc., were discussed based on relevant authoritative guidelines, expert consensus and literatures, and corresponding suggestions were given. (Chin J Ophthalmol, 2019, 55: 485-490).

[A multicenter study of the effectiveness and safety of Toric intraocular lens implantation]

Objective: To evaluate the effectiveness and safety of Proming(®)Toric intraocular lens (IOL) in adults with cataract combined with corneal regular astigmatism. Methods: Multicentre, randomized, open and positive parallel controlled clinical study. A total of 121 patients (121 eyes) who had cataract combined with corneal regular astigmatism and met the inclusion criteria were enrolled in 9 hospitals from May 2014 to May 2016. There were 45 males and 76 females and the median age was 71 (42-88) years old. A total of 121 patients (121 eyes) were randomly assigned to the study group and the control group through the Central Randomization System. Sixty patients (60 eyes) of the study group were implanted with Proming(®)Toric IOL (Model: AT1BH-AT6BH) from Eyebright Medical Technology (Beijing) Co., Ltd., and 61 patients (61 eyes) of the control group were implanted with AcrySof (®)IQ Toric IOL (Model: SN6AT2-SN6AT7) from Alcon Laboratories, Inc. The visual acuity, IOL axial position, slit lamp examination, residual astigmatism and contrast sensitivity were recorded at 1 day, 1 week, 1 month, 3 months, 6 months and 1 year postoperatively. Statistical analysis was performed using χ(2) test, independent sample t test, Mann-Whitney U test, Friedman repeated measured ANOVA on ranks and non-parametric 2-factor variance analysis. Results: A total of 118 patients completed 6 months of follow-up, including 59 from the study group and 59 from the control group. The difference between the two groups in terms of the percentage of best corrected distance visual acuity (BCDVA) reaching 20/40 was 1.69% [100% (59/59) vs. 98.31% (58/59) ], and the lower limit of the 95% CI (-1.60%) was greater than -10.00%. A total of 90 patients were followed up for 1 year, including 43 patients from study group and 47 patients from control group. At 1 year after operation, the percentages of the BCDVA up to 20/40 were 97.67%(42/43) in the study group and 97.87% (46/47) in the control group, and there was no significant difference between the two groups (χ(2)=0.00, P=0.95);the percentages of the uncorrected distance visual acuity (UCDVA) up to 20/40 were 81.40%(35/43) in the study group and 82.98%(39/47) in the control group, and there was no significant difference between the two groups (χ(2)=0.04, P=0.84). At 1 year follow-up, the difference of contrast sensitivity at 18.0 c/d under the bright light, dark light, bright glare and dark glare between the two groups was not statistically significant (U=468.50, P=0.17;U=528.00, P=0.28;U=465.50, P=0.19;U=629.00, P=0.39);the difference of residual astigmatism between the two groups was not statistically significant (U=798.50, P=0.08);the difference of IOL rotation degree between the two groups was not statistically significant (U=869.00, P=0.25). There were no severe inflammatory responses nor other complications associated with IOL in both groups at each follow-up point. Conclusion: The visual quality, astigmatism correction effect, rotation stability and safety of Proming(®)Toric IOL for the treatment of cataract combined with corneal regular astigmatism is equivalent to AcrySof(®) IQ Toric IOL. (Chin J Ophthalmol, 2018, 54: 349-356).

Prospective analysis of visual function changes in patients with dermatochalasis after upper eyelid blepharoplasty

OBJECTIVE

To evaluate the changes of visual acuity, contrast sensitivity, astigmatism, and higher order aberrations after blepharoplasty in patients with dermatochalasis.

METHODS

Two hundred six eyelids of 103 patients with dermatochalasis were prospectively studied. Visual acuity, contrast sensitivity, corneal topography, astigmatism degree, and higher order aberrations were examined and recorded before and at 1 month after upper eyelid blepharoplasty. Change in contrast sensitivity and astigmatism values were determined according to margin reflex distance of patients, which were classified into three following groups: <2 mm, 2-3 mm, and ⩾ 4 mm. A Wilcoxon signed rank test was performed to compare the difference.

RESULTS

No significant differences were observed for visual acuity (p = 0.157). The contrast sensitivity of patients significantly increased at all spatial frequencies both under glare and nonglare conditions (p < 0.05). The mean refractive astigmatism significantly decreased from ‒1.01 ± 1.3 to ‒0.79 ± 0.71, postoperatively (p = 0.029). In patients with marginal reflex distance < 2 mm, mean contrast sensitivity was increased (p < 0.001) and mean astigmatism was decreased significantly (p < 0.001) compared with those with ⩾ 2 mm. Higher order aberrations decreased significantly from 0.62 ± 0.41 µm to 0.55 ± 0.38 µm (p = 0.038) after blepharoplasty. Root mean square of the vertical trefoil (p = 0.038), vertical coma (p = 0.002), horizontal trefoil (p = 0.027), third-order aberration (p = 0.005), secondary vertical stigmatism (p = 0.001), spherical aberration (p = 0.023), secondary horizontal astigmatism (p = 0.002), fourth-order aberration (p = 0.024), vertical pentafoil (p = 0.015), secondary horizontal coma (p = 0.035), secondary horizontal trefoil (p = 0.030), and horizontal pentafoil (p = 0.048) were decreased significantly.

CONCLUSION

Upper eyelid blepharoplasty in patients with dermatochalasis has a significant improvement in visual function in terms of contrast sensitivity, astigmatism, and higher order aberrations.

[Therapeutic effect of rigid permeable contact lenses on irregular astigmatism after keratoplasty]

Objective: To evaluate the clinical effect of rigid permeable contact lenses (RGPCL) in the correction of irregular astigmatism after keratoplasty. Methods: Retrospective case study. From June 2012 to December 2016, 31 patients (37 eyes) who underwent corneal transplantation were tested and fitted with RGPCL. The patients' data of primary disease, interval from keratoplasty to contact lens fitting, uncorrected visual acuity, best spectacle-corrected visual acuity, best RGPCL-corrected visual acuity, contrast visual acuity before and after RGPCL wear, corneal topography and corneal endothelium parameters before and after RGPCL wear were collected, including ocular complications and comfort of contact lenses. Results: Among the 31 patients, 24 were male and 7 were female, with age of (31.3±5.8) years. The mean interval between grafting and initial contact lens fitting was (4.6±2.3) years. Uncorrected visual acuity, best spectacle-corrected visual acuity, and best RGPCL-corrected visual acuity were 0.81±0.21, 0.54±0.13, and 0.10±0.07, respectively (t=7.170, 16.617, 17.866; all P<0.05). The average astigmatism was -5.76±2.23 D and -0.83±0.47 D before and after wearing RGPCL (t=8.531, P<0.05). After wearing RGPCL, the contrast visual acuity of 100%, 25%, 10%, and 5% was increased from 0.95±0.33, 1.18±0.21, 1.40±0.00, and 1.40±0.00 to 0.12±0.15, 0.37±0.17, 0.65±0.25, and 0.96±0.29, respectively (t=5.972, 8.473, 9.243, 5.104; all P<0. 05). There were no obvious changes of corneal endothelium parameters during the observation period. No obvious corneal allograft rejection or other complications occurred, and 94.6% (35/37) of the patients felt comfortable with wearing RGPCL. Conclusions: RGPCL wear is safe and effective in correcting irregular astigmatism after corneal transplantation. We can obtain good corrected vision and improve contrast visual acuity, especially for patients who can not wear spectacles. (Chin J Ophthalmol, 2019, 55: 413-418).

Comparison of keratometric measurements between color light-emitting diode topography and Scheimpflug camera

Background

To determine the agreement of measurements between color light-emitting diode corneal topography (Cassini) and Scheimpflug camera keratometry (Pentacam HR).

Methods

The current retrospective study investigated 117 right eyes of 117 healthy patients before cataract surgery from June 2017 to July 2017. Steep K, flat K, mean K, astigmatism, and axis for both anterior and posterior corneal surface were measured using the two devices. The measured values were converted into J vectors such as J0 and J45. The mean difference for those measurement values were compared between the two instruments, and the agreement was evaluated using the Bland-Altman plot I.

Results

There were statistically significant differences in mean K (44.21D [43.34 to 45.34] and 44.30D [43.30 to 45.10] by Cassini and Pentacam [P = 0.004]) and astigmatism (0.90D [0.58 to 1.30] and 0.70D [0.40 to 1.30] by Cassini and Pentacam [P = 0.002]) on the anterior corneal surface and flat K (− 6.21D [− 6.39 to − 6.07] and − 6.30D [− 6.5 to − 6.10] by Cassini and Pentacam [P < 0.001]), mean K (− 6.39D [− 6.54 to − 6.25] and − 6.40D [− 6.60 to − 6.30] by Cassini and Pentacam [P = 0.019]), and astigmatism (0.33D [0.22 to 0.47] and 0.30D [0.15 to 0.40] by Cassini and Pentacam [P = 0.002]) on the posterior corneal surface. The mean difference (= Cassini – Pentacam) with 95% limit of agreement for mean K and astigmatism of the anterior corneal surface were 0.082D (− 0.60 to 0.76) and 0.11D (− 0.73 to 0.95) for measurements obtained by the two instruments, respectively. Regarding keratometric values from the posterior corneal surface, the mean differences for flat K, mean K, and astigmatism were − 0.081D (− 0.42 to 0.26), − 0.030D (− 0.32 to 0.26), and 0.067D (− 0.33 to 0.46), respectively. Intraclass correlation coefficients for steep K, flat K, mean K, and vector J0 were higher than 0.9 in the anterior cornea. Positive correlation in steep K, flat K, mean K, astigmatism, and J0 was found between two devices in both anterior and posterior cornea (P < 0.001).

Conclusions

Corneal refractive power and astigmatism tend to be higher when measured using Cassini than Pentacam HR in both anterior and posterior cornea. The two different devices might not be used interchangeably.

Trial registration

Retrospectively registered. Registration number: KC17RESI0439.

Efficacy of 4-Haptic Bitoric Intraocular Lens Implantation in Asian Patients with Cataract and Astigmatism

PURPOSE

To determine the efficacy of 4-haptic bitoric intraocular lens (IOL) implantation in Asian patients with cataract and astigmatism.

METHODS

A total of 19 eyes with ≤25.0 mm axial length and ≥0.75 diopters (D) corneal astigmatism were included in this prospective non-comparative study. All subjects underwent phacoemulsification with implantation of an AT Torbi 709M IOL. Visual and refractive outcomes as well as toric IOL axis were evaluated during a 3-month follow-up. Errors in predicted residual spherical equivalent were calculated by subtracting predicted residual spherical equivalent from postoperative refraction.

RESULTS

Uncorrected and corrected distance visual acuity improved significantly 3 months after surgery, from 0.43 to 0.05 and from 0.24 to -0.05, respectively. Mean refractive cylinders also decreased significantly, from -1.91 preoperatively to -0.54 D 3 months after surgery. Mean J0 and J45 decreased 3 months postoperatively, from 0.26 to 0.03 D and from 0.24 to -0.06 D, respectively. After 3 months, mean absolute IOL rotation was 1.81°. Errors in predicted residual spherical equivalent showed a hyperopic shift of 0.35 D.

CONCLUSIONS

Implantation of 4-haptic bitoric IOL proved to be effective for correcting astigmatism in Asian eyes during cataract surgery.

Utilizing intraoperative aberrometry and digital eye tracking to develop a novel nomogram for manual astigmatic keratotomy to effectively decrease mild astigmatism during cataract surgery

PURPOSE:

The purpose of the study is to develop a novel nomogram and validate with a retrospective comparative study for manual astigmatic keratotomy (MAK) with the assistance of intraoperative aberrometry (Optiwave Refractive Analysis [ORA]) and digital eye tracking (VERION) in mild astigmatic correction enhancement.

SETTING:

The study was conducted in Honolulu, Hawaii.

DESIGN:

This was a single-surgeon comparative study with retrospective data collection.

METHODS:

Sixty consecutive adult cataract surgery cases with regular astigmatism of 1.25 D or less were included for study from April 2016 to April 2017. VERION was used preoperatively in all cases. MAK was performed before phacoemulsification according to the surgeon's own nomogram. ORA then was utilized to obtain the axis and remaining cylinder power after phacoemulsification and intraocular lens implant implantation. MAK extension was performed for eyes with 1 D or more of remaining cylinder. Extensions were carried out slowly and slightly until the amount of cylinder was 1½ D or less under ORA. The mean degrees of extension plus the original MAK plan were calculated to develop the new nomogram. Sixty consecutive similar cases by the same surgeon using the surgeon's nomogram without using ORA/VERION for enhancement were reviewed from April 2015 to April 2016 for comparison. All patients included in this study signed the consent form.

RESULTS:

Using Alpins vector analysis for comparison, the proportion of patients with cylinder <0.5 D 3 months postoperatively was 87% in the ORA/VERION group compared to 70% in the non-ORA/VERION group (P < 0.05). Better than 20/25 best-corrected visual acuity was achieved more in the ORA/VERION group compared to non-ORA/VERION group.

CONCLUSIONS:

This novel nomogram developed by the surgeon may have better outcomes than the old surgeon's own nomogram. Further prospective control study is needed to validate the efficacy. If validated, those surgeons who do not have ORA/VERION can hopefully use this nomogram with greater success.

Correlation between iris-registered static and dynamic cyclotorsions with preoperative refractive astigmatism in PRK candidates

Purpose

To evaluate static and dynamic cyclotorsions during photorefractive keratotomy (PRK) surgery in refractive surgery candidates and their correlations with preoperative factors.

Methods

This cross-sectional case series was performed in 138 eyes of 77 patients who underwent PRK surgery by Technolas 217z100. Iris registration was used to evaluate the degree of static and dynamic cyclotorsion. Wavefront measurements were performed in sitting position using Zywave (versions 3.1 and 3.2, Bausch & Lomb) Hartmann Shack aberrometer (Bausch & Lomb), and the cyclotorsion from upright to supine position was measured using iris image comparison. Dynamic cyclotorsions were measured by Advanced Cyclotorsional Eye Tracker (ACE) mounted on Excimer laser machine Technolas 217z100 during surgery.

Results

The mean absolute static cyclotorsion that was captured in surgery time was 3.37 ± 2.38° (range, 0.00 to 11.30), and the mean absolute dynamic cyclotorsion was 2.54 ± 2.50° (range, 0.00 to 13.60). There was a significant correlation between dynamic cyclotorsions and static cyclotorsions (P < 0.001 and R = 0.704). There was a strong association between preoperative refractive astigmatism and range dynamic cyclotorsion. Total pulses (P = 0.009), ablation depth (P = 0.012), gender (P = 0.008) had significant correlations with cyclotorsional movements.

Conclusion

The measurements of static and dynamic cyclotorsions are highly recommended for refractive surgery candidates with significant preoperative refractive astigmatism.

Corneal dioptric power and astigmatism: A comparison between colour light-emitting diode based (CassiniTM) and Scheimpgflug technology (PentacamTM) topography

AIM

To determine the agreement and to compare the measurements obtained from a colour light-emitting diode based (Cassini^TM) and Scheimpflug (Pentacam^TM) based topography in the evaluation of the anterior, posterior, and total corneal power and astigmatism.

METHODS

A total of 30 eyes from 30 healthy patients were consecutively measured using Pentacam^TM and Cassini^TM. The main evaluated parameters were the anterior, posterior, and total dioptric power, and a power vector analysis of the astigmatism. The agreement between both devices was analysed using the intraclass correlation coefficient (ICC) and performing Bland-Altman plots. The comparison of means was performed using paired Student t-test.

RESULTS

The agreement between both devices when comparing the anterior and total corneal dioptric power was very high (ICC>0.85), but not when studying the posterior cornea (ICC<0.5). In the astigmatism analysis, measurements from the anterior cornea also showed an excellent agreement (ICC>0.78), but was poor for the corneal posterior surface (ICC<0.31). When studying the corneal dioptric power, no statistically significant differences were found for the anterior surface (P>.05), but Pentacam^TM obtained higher values for posterior and total surfaces (P<.001). As regards the magnitude of the astigmatism, no significant differences were found between both devices.

CONCLUSION

Both devices were highly comparable when studying the anterior cornea, but the agreement was poor-moderate when measuring posterior cornea. Therefore, the data obtained by both topographers are not interchangeable.

Prevalence and pattern of refractive errors among Saudi adults

Background & Objectives:

Refractive Errors (RE) are responsible for major portion of the treatable visual impairment and avoidable blindness in the world. The prevalence of RE varies with age, gender, ethnicity, geographical locations and also from time to time due to progresse in eye care services. We aimed to study the prevalence of RE and assess their patterns among Saudi adults of Arar city, the capital of Northern Border Region of Saudi Arabia.

Methods:

This is a cross-sectional, population-based study. A total number of 966 Saudi adults aged 16 to 39 years were enrolled. The patterns of their RE were studied through auto-refraction evaluation.

Results:

The prevalence of RE was 45.8%. The most frequent type of RE was myopia in 24.4%, followed by hyperopia 11.9% and astigmatism in 9.5% cases. Ages and genders significantly affect the prevalence of the different patterns of RE (0.033 and 0.012, respectively).

Conclusion:

The prevalence of RE in Arar city is slightly lower than that previously published in the same targeted age group. Myopia is the main RE. More awareness programs, especially among young adults are recommended for better outcomes.

Objective Verification of Physiologic Changes during Accommodation under Binocular, Monocular, and Pinhole Conditions

BACKGROUND

To objectively investigate accommodative response to various refractive stimuli in subjects with normal accommodation.

METHODS

This prospective, non-randomized clinical trial included 64 eyes of 32 subjects with a mean spherical equivalent -1.4 diopters (D). We evaluated changes in accommodative power, pupil diameter, astigmatic value, and axis when visual stimuli were applied to binocular, monocular (dominant eye, non-dominant eye, ipsilateral, and contralateral), and pinhole conditions. Visual stimuli were given at 0.25 D (4 m), 2 D (50 cm), 3 D (33 cm), and 4 D (25 cm) and accommodative response was evaluated using open view binocular autorefractor/keratometer.

RESULTS

The accommodative response to binocular stimulus was 90.9% of the actual refractive stimulus, while that of the monocular stimulus was 84.6%. The binocular stimulus induced a smaller pupil diameter than did the monocular stimulus. There was no difference in accommodative response between the dominant eye and non-dominant eye or between ipsilateral and contralateral stimuli. As the refractive stimuli became stronger, the absolute astigmatic value increased and the direction of the astigmatism axis became more horizontal. Pinhole glasses required 10%-15% less accommodative power compared with the monocular condition.

CONCLUSION

Binocular stimuli enable more precise and effective accommodation than do monocular stimuli. Accommodative response is composed of 90% true accommodation and 10% pseudo-accommodation, and the refractive stimulus in one eye affects the contralateral eye to the same extent. This should be taken into account when developing guidelines for wearing smart glasses while driving, as visual stimulation is applied to only one eye, but far distance attention is constantly needed.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03557346.

Health policy regulations pertaining to advanced surgical devices-their socio-economic effects on ophthalmology practice

The Israel Ministry of Health enacted regulations that aim to reduce private expenditure on healthcare services and mitigate social inequality. According to the modified rules, which went into effect in the second half of 2016, patients who undergo surgery in a private hospital and are covered by their healthcare provider’s supplemental insurance (SI) make only a basic co-payment.

The modified regulations limited the option of self-payment for advanced devices not covered by national health basket, meaning that patients for whom such devices are indicated had to pay privately for the entire procedure. These regulations applied to all medical and surgical devices not covered by national health insurance (NHI).

Toric intraocular lenses (IOLs) are a case in point. These advanced lenses are implanted during cataract surgery to correct corneal astigmatism and, in indicated cases, obviate the need for complex eyeglasses postoperatively. Toric IOL implantation has been shown to be highly cost-effective in both economic and quality-of-life terms. Limitations of the use of these advanced IOLs threatened to increase social inequality.

In 2017, further adjustments of the regulations were made which enabled supplemental charges for these advanced IOLs, performed through the SI programs of the healthcare medical organizations (HMOs). Allowing additional payment for these lenses at a fixed pre-set price made it possible to apply a supplemental part of the insurance package to the surgery itself. In mid 2018 these IOLs were included without budget in the national health basket, allowing for self-payment for the additional cost in addition to the basic coverage for all patients with NHI.

This case study suggests that, in their efforts to enhance health care equity, policymakers may benefit if exercising due caution when limiting the extent to which SI programs can charge co-payments. This is because, when a service or product is not available via the basic NHI benefits package, limiting SI co-payments can sometimes result in a boomerang effect - leading to an increase in inequality rather than the sought-after decrease in inequality.

Refractive error magnitude and variability: Relation to age

PURPOSE

To investigate mean ocular refraction (MOR) and astigmatism, over the human age range and compare severity of refractive error to earlier studies from clinical populations having large age ranges.

METHODS

For this descriptive study patient age, refractive error and history of surgery affecting refraction were abstracted from the Waterloo Eye Study database (WatES). Average MOR, standard deviation of MOR and astigmatism were assessed in relation to age. Refractive distributions for developmental age groups were determined. MOR standard deviation relative to average MOR was evaluated. Data from earlier clinically based studies with similar age ranges were compared to WatES.

RESULTS

Right eye refractive errors were available for 5933 patients with no history of surgery affecting refraction. Average MOR varied with age. Children <1 yr of age were the most hyperopic (+1.79D) and the highest magnitude of myopia was found at 27yrs (-2.86D). MOR distributions were leptokurtic, and negatively skewed. The mode varied with age group. MOR variability increased with increasing myopia. Average astigmatism increased gradually to age 60 after which it increased at a faster rate. By 85+ years it was 1.25D. J₀ power vector became increasingly negative with age. J₄₅ power vector values remained close to zero but variability increased at approximately 70 years. In relation to comparable earlier studies, WatES data were most myopic.

CONCLUSIONS

Mean ocular refraction and refractive error distribution vary with age. The highest magnitude of myopia is found in young adults. Similar to prevalence, the severity of myopia also appears to have increased since 1931.

Enantiomorphism and rule similarity in the astigmatism axes of fellow eyes: A population-based study

PURPOSE

To evaluate the relationship patterns between astigmatism axes of fellow eyes (rule similarity and symmetry) and to determine the prevalence of each pattern in the studied population.

METHODS

This population-based study was conducted in 2015 in Iran. All participants had tests for visual acuity, objective refraction, subjective refraction (if cooperative), and assessment of eye health at the slit-lamp. Axis symmetry was based on two different patterns: direct (equal axes) and mirror (mirror image symmetry) or enantiomorphism. Bilateral astigmatism was classified as isorule if fellow eyes had the same orientation (e.g. both eyes were with-the-rule) and as anisorule if otherwise.

RESULTS

Of the total cases of bilateral astigmatism, 80% were isorule, and in the studied population, the prevalence of isorule and anisorule astigmatism was 14.89% and 3.53%, respectively. The prevalence of isorule increased with age (p<0.001). The prevalence of both isorule and anisorule increased at higher degrees of spherical ametropia (p<0.001). Median inter-ocular axis difference was 10° in mirror symmetry and 20° in direct symmetry with no significant difference between two genders (p>0.288). Both symmetry patterns reduced with age (p<0.001). Among cases of bilateral astigmatism, 15.5% and 19.8% had exact direct and mirror symmetry, respectively.

CONCLUSION

Bilateral astigmatism is mainly isorule in the population and anisorule astigmatism is rare. The enantiomorphism is the most common pattern in the population of bilateral astigmatism.

Reversal of Toric Intraocular Lens-corrected Corneal Astigmatism after Kahook Dual Blade Goniotomy

A 79-year-old man underwent phacoemulsification (phaco) with TORIC intraocular lens (IOL) insertion combined with Kahook dual blade (KDB) goniotomy of the right eye several months after a stand-alone phaco in the fellow eye. He had significant against-the-rule astigmatism in both eyes (2.41D @ 10° right, 2.40D @ 160° left) preoperatively. Postoperatively, nearly all corneal astigmatism disappeared in the right eye (0.60D @ 37°), while it remained the same in the left eye (2.00D @ 167°). Ophthalmologists should be aware that KDB may have an unreported effect of altering corneal astigmatism, which should be considered when inserting TORIC IOL.

HOW TO CITE THIS ARTICLE

Hirabayashi MT, McDaniel LM, et al. Reversal of Toric Intraocular Lens-corrected Corneal Astigmatism after Kahook Dual Blade Goniotomy. J Curr Glaucoma Pract 2019;13(1):42-44.

The effects of experimentally induced graded monocular and binocular astigmatism on near stereoacuity

Purpose

To determine the effects of experimentally induced graded monocular and binocular astigmatism on near Stereoacuity in healthy adults.

Method

This prospective cross-sectional study was performed on 60 healthy adults ranging between 19 and 33 years of age recruited from College of Applied Medical Sciences. All subjects were emmetropic with normal binocular single vision, and stereoacuity of 40 sec of arc. Enrolled subjects were divided into four groups, each with 15 participants. Myopic astigmatism was induced in two groups, either monocularly or binocularly using +1.00 DC and +2.00 DC at different axes 45, 90 and 180. The remaining two groups were subjected to induced hypermetropic astigmatism using −1.00 DC and −2.00 DC at different axes 45, 90 and 180. The Titmus Fly Stereo Test was used to measure near stereoacuity both before and after induction of astigmatism.

Results

There was a reduction in stereoacuity with an increase in dioptric power of astigmatism (p < 0.05). In all groups, oblique astigmatism had the most significant effect followed by against the rule astigmatism and then with the rule astigmatism. Binocular induced hypermetropic astigmatism caused more reduction in stereoacuity than binocular induced myopic astigmatism, but statistically not significant. A similar impact was noted between monocular myopic astigmatism and monocular hyperopic astigmatism (p = 0.037), (p = 0.049) and (p = 0.044) with 2.00 D cylinder at 180, 90 and 45 axes, respectively.

Conclusion

The results indicate that the small amount of monocular or binocular astigmatism will affect on Stereoacuity, and the amount of reduction varies according to the axis of orientation.

Visual acuity in patients with keratoconus: a comparison with matched regular myopic astigmatism

PURPOSE

To compare uncorrected distance visual acuity (UDVA) and best-corrected distance visual acuity (CDVA) between patients with keratoconus (KC) and matched patients with regular myopic astigmatism.

METHODS

This retrospective study included consecutive patients diagnosed with KC between 2008 and 2013 at Care-Vision Laser Centers, Tel-Aviv, Israel, and matched patients with regular myopic astigmatism. Data included were central corneal thickness (CCT), spherical equivalent (SE), cylinder (CYL), mean keratometric power, maximum keratometric power (K_max), UDVA, CDVA, and defocus equivalent (DEQ).

RESULTS

The KC group included 734 patients with a mean age of 33.8 ± 9.5 years. The matched, control group included 1462 patients with a mean age of 33.2 ± 9.7 years (p = 0.14). The mean SE and CYL of the KC group were - 3.34 ± 3.29D and - 3.01 ± 1.99D, respectively, compared to - 3.34 ± 2.92D (p = 0.98) and - 2.97 ± 1.35 (p = 0.58). Mean K (46.8 ± 3.3D versus 44.0 ± 1.8D, p < 0.0001) and K_max (48.4 ± 4.0D versus 45.3 ± 2.0D, p < 0.0001) were statically significant higher in the KC group. CCT was significantly thinner in the KC group (444 ± 49 versus 527 ± 40 μm, p < 0.0001). The KC group had a better UDVA than the non-KC group (1.10 ± 0.68 versus 1.22 ± 0.64 logMAR, p < 0.0001). CDVA was significantly lower in the KC group (p < 0.001).

CONCLUSIONS

For defocus equivalents above 6D, the KC group had better UDVA than the non-KC group in spite of worse CDVA.

Comparison of clinical outcomes of toric intraocular lens, Precizon vs Tecnis: a single center randomized controlled trial

Background

To compare the clinical outcome of Precizon toric intraocular lens (IOL) (Ophtec Inc.) to that of Tecnis toric IOL (Abbott Medical Optics Inc.).

Methods

This randomized comparative study included 40 eyes (Precizon, 20 eyes; Tecnis, 20 eyes) of 40 patients with visually significant cataract and corneal astigmatism who underwent cataract surgery. Changes in uncorrected distant visual acuity (UCDVA), best corrected distant visual acuity (BCDVA), uncorrected intermediate visual acuity (UCIVA), refraction, residual astigmatism, rotation of the IOL axis, and higher order aberrations at 3 months postoperatively were evaluated. Vector analysis was performed using the Alpins method.

Results

Both groups showed significant reduction in refractive astigmatism after the surgery (Precizon: − 1.06 ± 0.94 Diopter (D) to − 0.31 ± 0.29 D, p = 0.042; Tecnis: − 1.83 ± 1.29 D to − 0.41 ± 0.33 D, p = 0.015). There was no significant (p > 0.05) difference in postoperative UCDVA, BCDVA, or residual astigmatism between the two groups, although a tendency of better UCIVA was observed in the Precizon group. Vector analysis parameters showed no statistically significant difference beween groups(P > 0.05). Significant difference in rotation of toric IOL axis was found between the two groups (Precizon: 1.50° ± 0.84, Tecnis: 2.56° ± 0.68, p = 0.010). Spherical aberration in the Precizon group was significantly (p = 0.005) lower than that in the Tecnis group.

Conclusions

The Precizon toric IOL group had better rotational stability at 3-month postoperatively. Both Precizon toric IOL and Tecnis toric IOL could be effectively used by cataract surgeons to correct preexisting corneal astigmatism through cataract surgery.

Trial registration

http://clinicaltrials.gov, NCT03085901, retrospectively registered on 21 March 2017.

Electronic supplementary material

The online version of this article (10.1186/s12886-018-0955-3) contains supplementary material, which is available to authorized users.

Outcomes of toric supplementary intraocular lenses for residual astigmatic refractive error in pseudophakic eyes

PURPOSE

To evaluate rotational stability and visual and refractive outcomes of supplementary toric IOLs (Sulcoflex Toric 653T, Rayner Intraocular Lenses Ltd) for residual astigmatic refractive error in pseudophakic eyes.

METHODS

A retrospective interventional case series was conducted in a single surgeon practice. Charts of patients who had Sulcoflex Toric supplementary IOLs inserted between June 2009 and September 2015 were reviewed. Outcomes were compared between eyes with and without prior corneal transplant. Patients with at least 3-months follow-up were included.

RESULTS

In 51 eyes, mean UDVA improved from 20/86 to 20/43 (p = 0.002), though UDVA was better in eyes without corneal grafts (20/31) than eyes with (20/62). The proportion of eyes achieving 20/20 UDVA was 43%, 61% and 17% overall, in eyes with prior graft and in eyes with no prior graft, respectively. Sixty-four percentage achieved a spherical equivalent of within 0.5D of target (84% no graft, 34% prior graft). Fifty-three percentage of eyes achieved a cylinder of within 0.5D of target (no graft: 73%, prior graft: 0%). Mean lens rotation was 8.23° on day 1, and mean maximal rotation during follow-up was 17.63°. Sixty-two percentage of IOLs required repositioning. Of those that required repositioning, this was conducted a mean of 2.3 times. The mean final IOL rotation (following repositioning if required) was 6.17°.

CONCLUSION

Sulcoflex Toric supplementary IOLs result in good visual and refractive outcomes in eyes with no prior corneal graft. However, outcomes are sub-optimal in eyes with prior corneal transplantation, and the majority of lenses require repositioning.

Comparative evaluation of two toric intraocular lenses for correcting astigmatism in patients undergoing phacoemulsification

Purpose:

To compare the efficacy of AT-TORBI plate haptic toric intraocular lens (IOL) (Carl Zeiss Meditec AG, Jena, Germany) and AcrySof loop haptic toric IOL (Alcon Laboratories, Inc., Fort Worth, TX, USA) for correcting preexisting astigmatism of ≥1 diopters (D) in patients undergoing phacoemulsification and to compare the rotational stability of these two toric IOLs.

Methods:

In this prospective randomized controlled trial. Forty-two eyes of 42 cataract patients with preexisting astigmatism of 1 D or more were randomized to receive plate haptic toric (AT TORBI) or loop haptic toric (AcrySof) IOLs, with 21 in each group. Postoperative evaluation was done at day 1, 1 week, 1 month, and 3 months. Uncorrected distance visual acuity (UDVA), best corrected visual acuity (VA), and IOL position were noted in both the groups.

Results:

At 3 months postoperatively, the mean log MAR UDVA was 0.23 ± 0.20 and 0.20 ± 0.13 in Groups I and II, respectively (P = 0.7), the mean residual cylindrical refractive error in plate haptic toric group was 0.40 ± 0.31 D and in loop haptic group was 0.45 ± 0.33 D (P = 0.64). The mean IOL rotation at 3 months follow-up in plate haptic group was found to be 3.52 ± 3.84° and in loop haptic group was 2.05 ± 2.56° (P = 0.25).

Conclusion:

Both types of toric IOLs were equally efficacious for attaining good uncorrected VA and correcting preexisting astigmatism between 1–5 D. Both of them were rotationally stable at 3 months follow-up.

Improving the Toric Intraocular Lens Calculation by Considering Posterior Corneal Astigmatism and Surgically-induced Corneal Astigmatism

PURPOSE

To investigate the effect of surgically induced corneal astigmatism (SICA) and total corneal astigmatism (TCA) estimation on the anterior corneal astigmatism (ACA)-based toric intraocular lens (IOL) calculation.

METHODS

Data from preoperative and postoperative corneal astigmatism, postoperative visual acuities, and refractive outcomes were collected. The incision was superior in with the rule anterior corneal astigmatism (WTRA) eyes and temporal in against the rule anterior corneal astigmatism eyes. The following five methods of calculating the toric IOL were compared: (1) ACA only and estimated SICA; (2) ACA with a fixed posterior corneal astigmatism (PCA) and estimated SICA; (3) ACA with a fixed PCA value and actual SICA; (4) and (5) TCA derived from the regression equations of ACA and actual SICA. The residual astigmatism was simulated. The Alpins method was used to analyze the astigmatism.

RESULTS

Sixty eyes from 46 patients were enrolled. Thirty eyes had WTRA and the other thirty had against the rule anterior corneal astigmatism. The vector and arithmetic means of the difference vector decreased when the information regarding the actual SICA and PCA was added to the calculation (from 0.59 diopters [D] @ 87.5° to 0.15 D @ 48.5°, and from 0.95 ± 0.53 to 0.71 ± 0.63 D, respectively; p < 0.001). The mean difference vector across the whole sample was lowest using model 5. The correction index was significantly closest to 1.0 in the WTRA group.

CONCLUSIONS

Researchers may improve the accuracy of post-implantation predictions by calculating toric IOL using exact SICA and TCA, with consideration of the PCA derived from the regression equation of ACA.

Predictive Factors for Successful High Myopia Treatment Using High-Frequency Laser-In-Situ Keratomileusis

Aim

To evaluate the predictive factors of LASIK procedure for high myopia with or without astigmatism using a combination of high-frequency femtosecond-assisted LASIK followed by an excimer laser.

Methods

This study was a retrospective interventional case series study to evaluate myopic eyes undergoing high platform LASIK with FEMTO LDV Z2 intervention, followed by WaveLight®EX500 excimer laser machine. Subjects were divided into 2 groups: high myopia (SE of -6.01 to -9.00 D) and very high myopia (SE of -9.01 D or higher). Myopic eyes (Spherical Equivalent/SE) less than -13 D were included in this study. Visual Acuity (VA) was evaluated 1 day and 60 days after the procedure. Predictive factors, such as age, degree of sphere, degree of astigmatism, keratometric reading and axial length were analyzed to detect any influences affecting the final VA results.

Results

A total of 316 myopia eyes underwent intervention, mean age: 25.3±3.8 years. Target treatment was achieved in 96.1% of patients with high myopia and 69.9% of patients with very high myopia. High degree of sphere and astigmatism constitutes an important factor influencing final VA.

Conclusion

Modern machines provide a more promising efficacy and success of LASIK procedure in high myopia: important predictive factors were a high degree of sphere and astigmatism for achieving the optimal final outcome.