Hyperopic Error Research Articles

Relation of postoperative refraction and anterior chamber depth changes after uneventful phacoemulsification

Background Following cataract surgery, the focus changed from relieving blindness to achieving precise refractive correction and rapid recovery. A lot of factors influence the visual outcome. The variance in postoperative anterior chamber depth (ACD) is one of the essential factors. Aim To record the differences in postoperative ACD measurements and its effects on postoperative refraction in individuals who had uneventful cataract surgery at Suez General Hospital. Patіents and methods Fifty eyes from fifty patients who underwent uneventful phacoemulsification by the same surgeon. Using the ocular biometer The IOLMaster 500 from ZEISS, (ACD) were assessed pre and postsurgery, 1 and 3 months after the procedure. The postoperative spherical equivalent were recorded. Results Mean age was (58.7±7.5) years. a highly significant difference in ACD values between preoperative and 1 and 3 months post-surgery (P<0.0001). While the ACD difference between 1 and 3 months postsurgery was insignificant (P=0.332). Fourteen (28%) of the eyes had a myopic spherical refractive error, 24 (48%) had a hyperopic refractive error, and 12 (24%) had no refractive error. An inverse association (r=–0.243, P=0.039) between the myopic sphere refractive errors and the variation in ACD. Conclusіon A high incidence of postoperative hyperopic shift spherical errors was linked to more extensive preoperative ACD measurements associated with less ACD deepening. While a more significant incidence of postoperative myopic shift spherical errors was linked to a small preoperative ACD with a greater degree of postoperative ACD deepening; therefore, postoperative ACD changes have a significant impact on postoperative refraction.

Photoreceptor layer elevation due to subretinal fluid: Impact on visual acuity measurements and simulation from biometrics.

Visual acuity (VA) is a primary outcome measure that defines the success of clinical interventions for retinal diseases such as age-related macular degeneration (AMD) or diabetic macular oedema (DME). These conditions can lead to the presence of subretinal fluid, causing substantial photoreceptor layer elevation. Hyperopic defocus then occurs, affecting the VA measurements. In this study, we simulated the induced hyperopic shift for real-world values of photoreceptor layer elevation and measured the effect on VA measurements. To simulate the hyperopic shift, we used a four-surface eye model. To measure the effect of defocus on VA, normally sighted adults (N = 44, mean [SD] age = 32 [13.0] year, range: 21-71 year) performed four test conditions, that is, defocus of 0.00, +0.75, +1.50 and +2.25 D. For each subject, mean VA and SD obtained from a cumulative normal fit to the VA data provided the coefficient of variation (CV) and 95% confidence interval (CI). Refractive error induced by photoreceptor layer elevation was maximum for hyperopic error conditions, followed by emmetropic and myopic refractive error conditions. The 76% threshold VA worsened with increasing defocus conditions. The 95% CI was significantly larger for +0.75, +1.50 and +2.25 D defocus compared to no defocus (p = 0.04, 0.02 and 0.01, respectively). The CI for the +2.25 D defocus condition was larger (3-10 letters) compared with no defocus (3-6 letters). Photoreceptor layer elevation causes a hyperopic shift sufficient for clinically meaningful changes: worse VA and more variable measurements.

Comparison of intraocular lens power formulas for negative-diopter intraocular lens implantation for high myopia.

To compare the accuracy of intraocular lens (IOL) power calculation formulas for myopic eyes requiring negative diopter powered IOLs. Retrospective case series. K… hospital and Y… Hospital, …, …. Sixty-one eyes that underwent phacoemulsification with implantation of a negative power IOL were investigated. The trueness, precision and accuracy of IOL power calculation were assessed for the Barrett Universal II (BUII), EVO 2.0, Haigis, Hoffer QST, Holladay 1 and SRK/T formulas using the Eyetemis online tool. The analysis was performed using 1) the ULIB IOL constants and 2) after constant optimization. With ULIB constants, the Haigis, Holladay 1 and SRK/T resulted in a hyperopic mean prediction error (PE) >1.00 diopter (D), which was significantly different from zero (adjusted p <0.05). The mean PE of the remaining formulas was closer to zero. The absolute PE was significantly higher with the Holladay 1 and SRK/T (adjusted p <0.05) with respect to the remaining formulas. After constant optimization, the outcomes of traditional formulas improved and no statistically significant differences were found among any of the formulas in terms of trueness, precision and accuracy. The percentage of eyes with an absolute PE within 0.50 D was low (<50%) even after constant optimization. With ULIB constants, the BUII, EVO 2.0 and Hoffer QST were more accurate than traditional formulas in eyes with negative-diopter IOLs. The results of IOL power calculation in these eyes remain poor even after constant optimization.

Analysis of factors influencing refractive error in Fuchs eyes undergoing Descemet membrane endothelial keratoplasty triple procedure

PurposeTo evaluate the accuracy of current intraocular lens (IOL) formulas and identify factors influencing mean error in eyes undergoing Descemet membrane endothelial keratoplasty (DMEK) triple procedure, that is, DMEK combined...

Analysis of intraocular lens displacement relative to the haptic plane by ultrasound biomicroscopy data

This study analyzed cases with postoperative displacement of intraocular lens (IOL) relative to the haptic plane using ultrasound biomicroscopy (UBM). The study analyzed biometry data of 231 patients (277 eyes) aged 72.39±7.77 years, among them 43.25% were males. IOL position and refraction were analyzed at 1, 3 and 6 months after standard phacoemulsification. UBM was performed to analyze the position of the IOL. Stabilization of lens position was observed by the 3rd month of observation. Among the cases with displacement of the optical part relative to the haptic plane, the forward shift was determined in 24.85%, backward - in 16.67% of cases. Eyes with opposite IOL displacements differed significantly in lens diameter, ciliary sulcus diameter and the power of implanted IOL. IOL shift towards the retina produced significant hyperopic refractive error. A discriminant function was compiled using preoperative biometry data comprising the model for predicting backward IOL displacement with high probability. However, we failed to obtain a qualitative model for forward IOL displacements. Calculation error in modern formulas could occur because of IOL displacement, including the shift of the optical part relative to the haptic plane in postoperative period. Analysis of biometry data allows calculating IOL displacement towards the retina with a high probability, which could help avoid hyperopic refraction error postoperatively.

Refractive error after combined phaco-vitrectomy: A multicentric study.

To study the post-operative refractive error (RE) of patients undergoing combined phaco-vitrectomy and to find out which intraocular lens (IOL)-power formula had the best refractive outcomes. In this retrospective multicentric study we compared the preoperative expected target with the postoperative RE of patients undergoing combined phaco-vitrectomy due to vitreomacular traction, macular pucker, full thickness macular hole or lamellar macular hole. A multinomial logistic regression was performed to compare the postoperative REs and the differences between expected and postoperative REs among the SRK-T, Olsen's and Holladay-2 formulas. The correlation between the difference in REs and IOL-power was also studied. Sixty-seven eyes with a mean axial length of 23.73 ± 1.21 mm were included. Forty-two (63%), 14 (21%) and 11 (16%) eyes were implanted with an IOL that was calculated respectively with SRK-T, Olsen's and the Holladay-2 formula. The mean preoperative expected- and post-operative REs were -0.16 ± 0.12D and -0.48 ± 0.17, respectively (p = 0.045). SRK-T and Holladay-2 formulas led to a significant myopic shift whereas Olsen's caused a significant hyperopic error, independently from the IOL power. Independently from the IOL power, none of the analyzed formulas is precise at calculating the post-operative RE.

Accuracy of Formulas for Intraocular Lens Power Calculation After Myopic Refractive Surgery.

To assess the accuracy of the following intraocular lens (IOL) power formulas: Barrett True-K No History (BTKNH), Emmetropia Verifying Optical 2.0 Post Myopic LASIK/PRK (EVO 2.0), Haigis-L, American Society of Cataract and Refractive Surgery (ASCRS) average, and Shammas, designed for patients who have undergone previous myopic refractive surgery, independent of preexisting clinical history and corneal tomographic measurements. Data from 302 eyes of 302 patients who previously underwent myopic refractive surgery and had cataract surgery done by a single surgeon with only one IOL type inserted were included. The predicted refraction was calculated for each of the formulas and compared with the actual refractive outcome to give the prediction error. Subgroup analysis based on the axial length and mean keratometry was performed. On the basis of mean absolute prediction error (MAE), the formulas were ranked as follows: Haigis-L (0.61 diopters [D]), ASCRS average (0.63 D), BTKNH (0.67 D), EVO 2.0 (0.68 D), and Shammas (0.69 D). The Haigis-L had a statistically significant lower MAE compared with all formulas (P < .05) except the ASCRS average. Hyperopic mean prediction errors were seen in all formulas for axial lengths of greater than 30 mm or mean keratometry values of 35.00 diopters or less. The Haigis-L and the ASCRS average formulas provided the most accurate results in the overall population evaluated in this study. Moreover, according to data observed, it is important to be careful handling very long eyes and very flat corneas because hyperopic refractions could be more common. [J Refract Surg. 2022;38(7):443-449.].

Predictability of 6 Intraocular Lens Power Calculation Formulas in People With Very High Myopia.

PurposeTo investigate the accuracy of 6 intraocular lens (IOL) power calculation formulas in predicting refractive outcomes in extremely long eyes.SettingDepartment of Ophthalmology, Far Eastern Memorial Hospital, Taiwan.DesignRetrospective comparative study.MethodsIn this retrospective single-center study, we reviewed 70 eyes of 70 patients with axial length (AL) ≥ 28 mm who had received an uneventful 2.2 mm corneal wound phacoemulsification and in-the-bag IOL placement. The actual postoperative refractive results were compared to the predicted refraction calculated with 6 formulas (Haigis, Hoffer Q, Holladay 1, SRK/T, T2, Barrett Universal II formulas) using IOLMaster 500 as optical biometry in the User Group for Laser Interference Biometry (ULIB) constants.ResultsOverall, the Haigis and Barrett formulas achieved the lowest level of mean prediction error (PE) and median absolute error (MedAE). Hoffer Q, Holladay 1, SRK/T, and T2 had hyperopic prediction errors (p < 0.05). The Hoffer Q and Holladay 1 had significantly more MedAE between the 6 formulas. After the mean PE was zeroed out, the MedAE had no significant difference between each group. The absolute error tends to be larger in patients with longer AL. The absolute errors were 30.0–37.1% and 60.0–64.3% within 1.0 D of all patients compared to predicted refraction calculated using various formulas.ConclusionThe Haigis and Barrett Universal II formulas had a better success rate in predicting IOL power in high myopic eyes with AL longer than 28 mm using the ULIB constant in this study. The postoperative refractive results were inferior to the benchmark standards, which indicated that the precision of IOL power calculation in patients with high myopia still required improvement.

Refractive Outcomes of Uneventful Cataract Surgery in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma.

PurposeTo compare the refractive outcomes after cataract surgery between patients with and without pseudoexfoliation, and to evaluate the risk factors of refractive error.MethodsRetrospective review of 210 eyes with pseudoexfoliation (study group) and 510 normal eyes (control group) that underwent uneventful phacoemulsification with intraocular lens implantation. The study group included pseudoexfoliation syndrome and pseudoexfoliation glaucoma (PXG) subgroups. The main outcome measure was refractive error, defined as the difference between the target refraction and postoperative refraction in diopter (D). A refractive error >±1.0 D was identified as a large-magnitude refractive error. The frequency of the large-magnitude refractive error was compared between study and control groups, and also between each subgroup and normal eyes. The factors influencing refractive error were analyzed by logistic regression.ResultsThere was a significantly higher frequency of a refractive error >± 1.0 D and hyperopic error >1.0 D in the study group than in the control group (p = 0.001 and p = 0.003, respectively). In the multivariate logistic regression analysis, PXG and poor preoperative visual acuity were related with a large-magnitude refractive error (p = 0.001 and p = 0.02, respectively) Refractive error >± 1.0 D and hyperopic error >1.0 D were noted more often in PXG eyes that had an intraocular pressure spike >25 mmHg at postoperative first 24 hours (p = 0.01 and p=0.03, respectively).ConclusionsThe eyes with pseudoexfoliation were at a high risk for refractive error, especially in the presence of glaucoma. In PXG, the only significant risk factor for refractive error was observed to be the presence of an intraocular pressure spike.

Phacoemulsification and calculation of intraocular lenses in patients given keratorefractive surgery. Part 2

Effective rehabilitation of patients with cataracts who underwent keratorefractive surgeries requires that the optical power of the IOL be calculated correctly to avoid hyperopic error. The purpose of the 2nd part of the research (for the 1st part, see ROJ, 2021; 14 (2): 55–58) is to present the results of cataract phacoemulsification in patients subjected to keratorefractive surgery based on the author’s algorithm for calculating the optical power of the IOL. Material and methods. The algorithm used optical biometry with an IOL-Master device. The main technique of improving the accuracy of IOL calculation after keratorefractive operations has been to introduce amendments to standard IOL calculation formulas. This work proposes an alternative, which consists in using the Hoffer Q formula, as it is more consistent with changes in the anterior segment of the myopic eye after keratorefractive surgery than other basic. The main distinguishing feature of the Hoffer Q formula is that the corneal refraction is not converted into the radius of curvature but is applied directly as the optical power of a “thin lens”. Results. The empirical customized correction was +1.0 D with regard to the estimated planned postoperative refraction (for patients with initial myopia from -3 to -9 D). The use of the “thin lens” principle made it possible to extrapolate this formula and apply it after LASIK surgery and after radial keratotomy. Conclusion. The proposed technique of IOL calculation was implemented for cataract phacoemulsification in over 200 patients who underwent keratorefractive surgeries. No cases of hyperopic shift of postoperative refraction were noted. The deviation from the planned myopic refraction did not exceed 1.0 D.

Surgeon effects on cataract refractive outcomes are minimal compared with patient comorbidity and gender: an analysis of 490 987 cases

AimTo investigate effect of patient age, gender, comorbidities and surgeon on refractive outcomes following cataract surgery.MethodsStudy population: patients on UK national ophthalmic cataract database on cataract operations undertaken between 1...

Refractive accuracy in eyes undergoing combined cataract extraction and Descemet membrane endothelial keratoplasty

PurposeTo evaluate the refractive accuracy of current intraocular lens (IOL) formulas and propose a modification in calculation of corneal power in eyes undergoing combined cataract extraction and Descemet membrane endothelial...

Analysis of visual outcome following cataract surgery in axial myopic patients

Aim: The primary outcome is to assess visual outcomes following cataract surgery in axial myopic patients. The secondary outcome assessed is perioperative complications rate due to high axial length. Materials and Methods: Type of study: It was a retrospective, noncomparative case series study. Inclusion criteria: Patients with axial length more than or equal to 25 mm with visually significant cataract in one or both eyes were recruited for the study. Patients with pathological myopia were also included – visual recovery was assessed in conjunction with the preoperative best-corrected visual acuity. Exclusion criteria: Myopic patients with cataract with other causes of visual loss such as macular scar, diabetic retinopathy, age-related macular degeneration, disc edema, vein occlusion, and epiretinal membrane were excluded from the study. Sample Size: The sample size of the study was 32 patients (49 eyes). All patients recruited for the study underwent complete anterior segment examination in slit lamp with due importance to the type of cataract, visual acuity examination, and refraction to assess preoperative best-corrected visual acuity and posterior segment examination with 90 D lens. If the posterior segment was not visualized, B-scan was done. Blood investigations include complete blood count, random blood sugar, HIV, hepatitis B virus surface antigen, and urine albumin/sugar. With the test results and electrocardiogram, anesthetist fitness was obtained. Duct patency and intraocular pressure (IOP) were measured. Automated keratometry and axial length were measured by immersion technique done to calculate intraocular lens (IOL) power. IOL power calculation was performed using the SRK/T which was found to be reliable in axial lengths above 25 mm. Anterior chamber depth and lens thickness were also measured. All patients underwent phacoemulsification with IOL implantation by experienced single surgeon. The main outcomes measured were visual acuity after cataract surgery with implantation of zero or negative or very low IOL power at 1-month postoperative period and intraoperative and postoperative complications. The method of surgery did not influence the visual outcome. Results: The mean age of the patient operated on was about 61.9 years. In our study, the most common type of cataract was nuclear cataract (63.2%). Only 4.1% had previous refractive surgery. About 65.3% had 6/6 vision postcataract surgery with axial myopia. About 51.1% of axial myopic patients' fundus changes before cataract surgery which could be one of the causes for poor visual acuity. No significant perioperative complications were observed. Conclusion: Good postoperative outcomes following cataract surgery were observed in patients with cataract and high myopia. Refractive error is a potential complication as the hyperopic error appears to increase with axial length, especially in patients receiving negative power lens. If a sulcus IOL is inserted, it is more likely to be unstable or decenter because of the larger sulcus size. The need for Nd: YAG capsulotomy for posterior capsular opacity was found to be more common in myopes with high axial length compared to the general population. IOP reduction is slower and unstable for the first 30 days of postcataract surgery in highly myopic eyes.

Hyperopic shifts and anterior curvature flattening after Descemet-stripping endothelial keratoplasty and cataract surgery in 2 patients with a history of myopic LASIK

Two patients with a history of myopic laser in-situ keratomileusis (LASIK) experienced larger-than-expected hyperopic results after cataract surgery and Descemet-stripping endothelial keratoplasty (DSEK) for Fuchs endothelial corneal dystrophy. Although an anticipated hyperopic shift from DSEK-related posterior curvature steeping was taken into account during IOL power calculations, the refractive outcome was still more hyperopic than expected. Postoperative analysis revealed significant and unexpected flattening of the anterior corneal curvature that is not common after standard DSEK. Central anterior stromal ablation from myopic LASIK might make the cornea more prone to swelling and anterior steepening as Fuchs dystrophy progresses, increasing corneal power. A subsequent reduction in swelling might then cause central flattening and contribute to hyperopic errors after combined cataract–endothelial keratoplasty surgery.

Refractive enhancements for residual refractive error after cataract surgery.

Advances in cataract surgery have allowed surgeons to achieve superior refractive outcomes but have also led to higher patient expectations. Despite ever-evolving technology, residual refractive errors still occur. Postcataract refractive enhancements may be required to deliver satisfactory visual outcomes. This review aims to discuss the potential causes of residual refractive errors and the various enhancement modalities to correct them. A thorough preoperative workup to detect and address underlying pathologic causes of impaired vision should be performed prior to enhancement or corrective procedures. Corneal-based procedures are the safest and most accurate methods of correcting mild cases of residual refractive error. Hyperopic, high myopic, and high astigmatic errors are best managed with lens-based enhancements. Piggyback intraocular lenses (IOLs) are safer and more effective compared with IOL exchange. Toric IOL rotation and IOL exchange are ideally performed in the early postoperative period. A multitude of options exist for effective correction of residual refractive errors. The choice on how to best manage these patients depends on many factors such as the cause of refractive error, type of IOL used, ocular comorbidities, and patient preference.

Eccentricity-dependent effects of simultaneous competing defocus on emmetropization in infant rhesus monkeys

Dual-focus lenses that impose simultaneous competing myopic defocus over the entire visual field produce axial hyperopic shifts in refractive error. The purpose of this study was to characterize the effects of eccentricity on the ability of myopic defocus signals to influence central refractive development in infant monkeys. From 24 to 152 days of age, rhesus monkeys were reared with binocular, dual-focus lenses that had central, zero-powered zones surrounded by alternating concentric annular power zones of +3D and zero power. Between subject groups the diameter of the central, zero-powered zone was varied from 2 mm to 8 mm in 2 mm steps (+3D/pl 2 mm, n = 6; +3D/pl 4 mm, n = 6; +3D/pl 6 mm, n = 8, or + 3D/pl 8 mm, n = 6). For the treatment lens with 2, 4, 6 and 8 mm central zones, objects at eccentricities beyond 11°, 16°, 19° and 23°, respectively, were imaged exclusively through the dual-power peripheral zones. Refractive status (retinoscopy), corneal power (keratometry) and axial dimensions (ultrasonography) were measured at two-week intervals. Comparison data were obtained from monkeys reared with binocular, single-vision +3D full-field lenses (+3D FF, n = 6) and 41 normal control monkeys reared with unrestricted vision. At the end of the rearing period, with the exception of the +3D/pl 8 mm group (median = +3.64 D), the ametropias for the other lens-reared groups (medians: FF = +4.39 D, 2 mm = +5.19 D, 4 mm = +5.59 D, 6 mm = +3.50 D) were significantly more hyperopic than that for the normal monkeys (+2.50 D). These hyperopic errors were associated with shallower vitreous chambers. The key finding was that the extent and consistency of these hyperopic ametropias varied with the eccentricity of the dual-focus zones. The results confirm that myopic defocus in the near periphery can slow axial growth, but that imposed defocus beyond about 20° from the fovea does not consistently alter central refractive development.

Assessment of Refractive Error Changes and Factors for Decompensation in Patients With Fully Accommodative Esotropia.

To determine the factors affecting the risk of deterioration and evaluate the refractive error change in patients with fully accommodative esotropia. Patients diagnosed as having fully accommodative esotropia (esotropic deviation that started before 7 years of age and less than 8 to 10 prism diopters [PD] of esotropia with full hyperopic correction and/or bifocals) were included in this retrospective population-based cohort study. Refractive error changes were recorded. For comparisons, patients were divided into two groups: nondecompensated fully accommodative esotropia group and decompen-sated fully accommodative esotropia group. Two hundred and twenty-three patients met the inclusion criteria. The mean follow-up time was 5.94 ± 0.31 years (range: 5 to 8 years). The changes in spherical equivalent in the younger than 7 years, 7 to 12 years, and 12 to 17 years groups were statistically significant (P < .001). The decrease of hypermetropia was 0.13 diopters/year between 7 and 12 years and 0.06 diopters/year between 12 and 17 years. Forty-one of 223 patients (18.4%) discontinued spectacle therapy during the follow-up period. Hyperopic error and presence of amblyopia were lower, whereas visual acuity level and presence of near-distance disparity were higher in the spectacle discontinuation group (P < .001, .007, .01, and 0.01, respectively). Deterioration of fully accommodative esotropia occurred in 30 of 223 patients (13.5%). Boys were more likely to require strabismus surgery (P = .32). The mean age at presentation, esotropia angle with and without refractive correction at both near and distance fixation, near distance disparity, and inferior oblique overaction were significantly higher in patients with decompensated fully accommodative esotropia. Hyperopic error increased from the initial level until 7 years of age, followed by a myopic shift thereafter. Few children had resolution of fully accommodative esotropia and could discontinue spectacle therapy. Children with male gender, higher esotropia angle, older age at presentation, near-distance disparity, and inferior oblique overaction experienced a greater deterioration of the fully accommodative esotropia. [J Pediatr Ophthalmol Strabismus. 2020;57(4):217-223.].

Accuracy of Intraocular Lens Power Formulas Modified for Patients with Keratoconus

To assess the accuracy of intraocular lens (IOL) power formulas modified specifically for patients with keratoconus (Holladay 2 with keratoconus adjustment and Kane keratoconus formula) compared with normal IOL power formulas (Barrett Universal 2, Haigis, Hoffer Q, Holladay 1, Holladay 2, Kane, and SRK/T). Retrospective consecutive case series. A total of 147 eyes of 147 patients with keratoconus. Data from patients with keratoconus who had preoperative IOLMaster biometry were included. A single eye per qualifying patient was randomly selected. The predicted refraction was calculated for each of the formulas and compared with the actual refractive outcome to give the prediction error. Subgroup analysis based on the steepest corneal power measured by biometry (stage 1: ≤48 diopters [D], stage 2: >48 D and ≤53 D, and stage 3: >53 D) was performed. Prediction error. On the basis of the mean absolute prediction error (MAE), the formulas were ranked as follows: Kane keratoconus formula (0.81 D), SRK/T (1.00 D), Barrett Universal 2 (1.03 D), unmodified Kane (1.05 D), Holladay 1 (1.18 D), unmodified Holladay 2 (1.19 D), Haigis (1.22 D), Hoffer Q (1.30 D), and Holladay 2 with keratoconus adjustment (1.32 D). The Kane keratoconus formula had a statistically significant lower MAE compared with all formulas (P < 0.01). In stage 3 keratoconus, all nonmodified formulas had a hyperopic mean prediction error ranging from 1.72 to 3.02 D. The Kane keratoconus formula was the most accurate formula in this series. The SRK/T was the most accurate of the traditional IOL formulas. All normal IOL formulas resulted in hyperopic refractive outcomes that worsened as the corneal power increased. Suggestions for target refractive aims in each stage of keratoconus are given.

The frequency of refractive errors required to be corrected in childhood among Turkish children

Background: The aim of this study is to investigate the distribution of refractive errors needed to be correct in childhood. Material and methods: Children applied and received glasses prescriptions were recruited. Age, gender, spherical, cylindrical error, and spherical equivalent (SE) were noted. The refractive errors were classified as myopic, hyperopic and cylindrical errors according to the SE and prescriptions. Cylindrical errors were subdivided into myopic, hyperopic. Children were classified into 4 groups. Group 1, 2, 3 and 4 composed of children whose ages were between 0–5, 6–10, 11–15 and 16–18 years, respectively. Results: There were 846 children in group 1, 3931 in group 2, 5948 in group 3, 3896 in group 4, and a total of 14621 children. The rates of myopia and hyperopia were 72.4% and 27.6%. Myopic and hyperopic astigmatism were found in 29.1% and 11.3% of children. Myopia, myopic astigmatism increased with age (p &lt; 0.05). The hyperopia rate decreased with decreasing age (p &lt; 0.05). The frequency of myopia, myopic astigmatism was higher in both male and female children (p &lt; 0.05). The rate of myopia was higher in females (p &lt; 0.05). There was no statistically significant difference in terms of cylindrical value between genders. The statistically significant difference was found in terms of mean SE among all groups and a negative correlation was present between age and mean SE. A lower negative correlation was stated between age and cylindrical value. Conclusion: Corrected myopic and myopic astigmatism errors were higher than hyperopic refractive errors. The prevalence of myopia increased by age and was higher in females. The need for glasses was highest in children whose age range was between 11 and 15 years.

Accuracy of intraocular lens power calculations in paediatric eyes.

There is no clear consensus on which intraocular lens (IOL) power calculation formula provides the best refractive prediction in the paediatric population. To evaluate the predictability of desired postoperative refractive outcomes by using six IOL formulas in paediatric cataract cases. Retrospective case series. A total of 377 eyes in 377 paediatric patients (<13 years of age) who received primary IOL implants in the capsular bag. This study utilized formulas, namely, SRK II, SRK/T, Hoffer Q, Holladay 1, T2 and Super formula. Prediction errors were calculated based on the difference between the postoperative refraction and the refraction predicted by each formula. The mean prediction error, mean absolute error, median absolute error, percentages of eyes within the prediction errors of ±0.50 D, ±1.00 D and ± 2.00 D. The mean axial length was 22.48 ± 1.91 mm (<22.0 mm for 161 eyes). The average age at surgery was 55.21 ± 28.01 months (<24 months for 37 eyes). The mean prediction error was positive (hyperopic error) with all formulas. Compared to the other IOL power formulas, SRK II showed significantly higher absolute errors (P < .001). Hoffer Q and Holladay 1 generated the least absolute error, followed closely by Super formula. Multiple logistic analyses indicated that age at time of surgery was an independent factor significantly contributing to the refractive surprise using all formulas. SRK II was the least predictable formula in this study. HofferQ and Holladay 1 yielded the best predictive values.