Long-term follow-up of cataract surgery in eyes filled with silicone oil

AIM:To evaluate the refractive and long-term outcome of eyes filled with silicone oil(SO)undergoing phacoemulsification cataract surgery(PCS).METHODS:This retrospective study evaluated patients with SO tamponade who were scheduled for PCS.RESULTS:Subjects(n=26)were followed for 29.5±13.9 mo after cataract surgery.The median spherical equivalent refraction(SER)was+5.3 D[interquartile range(IQR)+2.9 to+6.7]before PCS,and+3.4 D(IQR+2.0 to+4.4)after PCS.Within the follow-up period retinal reattachment after SO removal was achieved in 15 out of 26 eyes(57.7%).In 13 eyes assessment of refraction after SO-removal was possible,and showed a myopic shift of-4.6 D(IQR-2.9 to-7.3)in the SER.After SO removal,5 of the 13 eyes(38.5%)were within±1.0 D of the target refraction,while 9 out of the 13 eyes(69.2%)were within±2.0 D.CONCLUSION:In our study,the refraction after PCS for eyes filled with SO manifested low predictability,as did the myopic shift following SO removal.A significant percentage of the eyes that underwent SO administration required a long-term tamponade.     

Corneal and corneal epithelial thickness distribution characteristics in healthy North Indian eyes using spectral domain optical coherence tomography

Purpose:To determine the pattern of corneal thickness and epithelial thickness distribution in healthy North Indian eyes by using spectral domain optical coherence tomography (SD-OCT).Methods:The observational study measured total corneal and epithelial thickness in the central 2 mm zone and eight sectors each in paracentral 2–5 mm (ring 1) and midperipheral 5–7 mm (ring 2) zones on SD-OCT.Results:The study included 67 eyes of 67 subjects with a male:female ratio of 32:35 and mean age of 25.04 ± 4.54 years. The mean central corneal and epithelial thicknesses were 505.97 ± 30.12 mm and 60.48 ± 8.37 mm, respectively. The epithelium of inferior and infero-nasal sectors in ring 1 and inferior sector in ring 2 was significantly thicker than the radially opposite sectors of the respective rings (P = 0.001; P = 0.01 and P = 0.02, respectively). Sector-wise analysis did not reveal any significant correlation between the total corneal thickness and epithelial thickness (all P > 0.05) except in the outer superior sector where there was a weak positive correlation (r = 0.28, P = 0.02). Central epithelial thickness in males (60.59 ± 9.28 mm) and females (60.37 ± 7.58 mm) was comparable (P = 0.91). Pachymetry was thinnest in the inferior, inferonasal, and inferotemporal sectors in 44.79% of eyes (n = 30), while thinnest epithelium was seen in the superior, superonasal, and superotemporal quadrants in 50.75% of eyes (n = 34)Conclusion:The epithelial thickness distribution in this sample of topographically normal healthy North Indian eyes was nonuniform and independent of the underlying corneal thickness. Epithelium was thinner in the superior cornea, whereas total corneal thickness was minimum in the inferior part.     

Measurement of refractive,wavefront, topographic,and keratometric changes attributable to epithelial removal in keratoconus

ObjectiveThe corneal epithelium is able to mask topographic and keratometric abnormalities of the underlying Bowman layer in keratoconus, but its contribution to refractive and wavefront parameters has not yet been studied. This study compared the refractive and aberrometric features of the corneal epithelium and Bowman layer in eyes with keratoconus before and after epithelial debridement.MethodsCorneal refractive and wavefront variables were measured in patients with keratoconus undergoing corneal crosslinking—immediately before and after epithelial debridement using a third-generation combined corneal topographer, autorefractor, and aberrometer.ResultsAfter epithelial debridement, there were significant changes in spherical equivalent (?1.37 D; p < 0.01) and asphericity (?0.64; p = 0.03). The mean difference in the magnitude of epithelium-induced astigmatism in the 3rd and 5th central millimeter rings was 0.44 ± 3.20 D × 8 and 0.43 ± 2.75 D × 21 (positive cylinder), respectively. Corneal astigmatism axis shifted in the against-the-rule orientation after epithelial debridement. There were no significant changes in any corneal higher-order aberration parameter after epithelial debridement (p > 0.05).ConclusionsIn eyes with keratoconus, epithelial debridement increased the magnitude of anterior corneal prolateness and tended to increase astigmatism and shift its axis toward the against-the-rule orientation. This study supports the notion that the corneal epithelium smooths underlying Bowman layer irregularity in keratoconus.     

A short-term study of corneal collagen cross-linking with hypo-osmolar riboflavin solution in keratoconic corneas

AIM: To report the 3mo outcomes of collagen cross-linking (CXL) with a hypo-osmolar riboflavin in thin corneas with the thinnest thickness less than 400 μm without epithelium. METHODS: Eight eyes in 6 patients with age 26.2±4.8y were included in the study. All patients underwent CXL using a hypo-osmolar riboflavin solution after its de-epithelization. Best corrected visual acuity, manifest refraction, the thinnest corneal thickness, and endothelial cell density were evaluated before and 3mo after the procedure. RESULTS: The mean thinnest thickness of the cornea was 408.5±29.0 μm before treatment and reduced to 369.8±24.8 μm after the removal of epithelium. With the application of the hypo-osmolar riboflavin solution, the thickness increased to 445.0±26.5 μm before CXL and recover to 412.5±22.7 μm at 3mo after treatment, P=0.659). Before surgery, the mean K-value of the apex of the keratoconus corneas was 57.6±4.0 diopters, and slightly decreased (54.7±4.9 diopters) after surgery (P=0.085). Mean best-corrected visual acuity was 0.55±0.23 logarithm of the minimal angle of resolution, and increased to 0.53±0.26 logarithm after surgery (P=0.879). The endothelial cell density was 2706.4±201.6 cells/mm2 before treatment, and slightly decreased (2641.2±218.2 cells/mm2) at last fellow up (P=0.002). CONCLUSION: Corneal collagen cross-linking with a hypo-osmolar riboflavin in thin corneas seems to be a promising treatment. Further study should be done to evaluate the safety and efficiency of CXL in thin corneas for the long-term.     

Comparison of posterior corneal elevation in children with and without vernal keratoconjunctivitis using a new tomographer

Purpose:To assess the posterior corneal elevation (PCE) in children with vernal keratoconjunctivitis (VKC) and compare the same with that of age and gender-matched normal children.Methods:This was a case control study. We included 110 children attending the Pediatric ophthalmology outpatient department of a tertiary eye care center in South India between September 2019 and June 2020. Fifty-five children with VKC and 55 normal age and gender-matched children were examined by Sirius tomographer/topographer (CSO, Italy) to determine the PCE, thinnest corneal thickness (TCT), simulated K (Sim K), keratoconus front (KVf) and keratoconus vertex back (KVb). The parameters were compared between the two groups.Results:A total of 220 eyes of 110 children were examined. The mean age in both groups was 10.44 ± 3.28 years, each group included 44 males and 11 females. There was no statistically significant difference in TCT and Sim K between the two groups. The mean PCE was 18.8 ± 8.4 μm in VKC group and 11.7 ± 3.9 μm in control group (P < 0.001). Both KVf and KVb were significantly higher in VKC group when compared to the control group.Conclusion:Children with VKC have significantly higher PCE as measured by Sirius tomographer, and hence, all VKC children should be screened for development of KC and the Sirius tomographer may be an appropriate tool for the same.     

In-vivo corneal biomechanical analysis of unilateral keratoconus

AIM: To evaluate and compare corneal biomechanical findings measured by ocular response analyzer, topographic and pachymetric findings in patients with unilateral keratoconus patients and healthy controls. METHODS: This is an observational, case-control study. Patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with sex and age matched with controls healthy subjects. All subjects were evaluated with rotating scheimpflug imaging system. The receiver-operating-characteristic curves were analyzed to evaluate the sensitivity and specificity of the parameters. RESULTS: Twenty-seven patients with keratoconus in one eye and forme fruste keratoconus in the fellow eye were compared with 40 eyes of 40 normal subjects. Corneal hysteresis (CH) was 8.0±1.7 mm Hg in keratoconus group, 8.3±1.6 mm Hg in forme fruste keratoconus group, and 9.8±1.6 mm Hg in control groups (P=0.54 between keratoconus and forme fruste keratoconus groups, P<0.01 between control group and other groups). Corneal resistance factor (CRF) was 7.1±2.2 mm Hg in keratoconus group, 7.8±1.2 mm Hg in forme fruste keratoconus group and 9.9±1.5 mm Hg in control group (P<0.001 between control group and other groups). Using receiver-operating-characteristic analysis, the area under curve values of the parameters to distinguish forme fruste keratoconus from control subjects were: CH (0.768), CRF (0.866). Best cut-off points were 9.3 mm Hg and 8.8 mm Hg for CH and CRF respectively. CONCLUSION: Ocular response analyzer parameters (CH and CRF) are found to be significantly lower in forme fruste keratoconus patients compared to normal control subjects.     

The Intraoperative Corneal Pachymetry Changes during Accelerated Corneal Cross-linking in Progressive Keratoconus Patients with Thin Corneas

PurposeTo report the intraoperative corneal pachymetry changes during accelerated corneal cross-linking (A-CXL) in progressive keratoconus patients with thin corneas.MethodsThirty-six eyes (mean age, 22.26 ± 4.02 years) with progressive keratoconic thin corneas (<400 μm without epithelium) who underwent A-CXL with ultraviolet (UV)-A (UVA) (9 mW/cm²) using isotonic riboflavin5-phosphate 0.1% with 1.1% hydroxypropyl methycellulose (RF-HPMC, MedioCROSS M) were included in this retrospective study. Intraoperative corneal pachymetric changes were noted before the procedure, after removal of epithelium, after RF-HPMC instillation, before and after UV irradiation. The mean of corneal pachymetric values were compared statistically.ResultsThe mean corneal pachymetry reduced from 415.72 ± 29.66 to 369.50 ± 23.45 μm after removal of the epithelium (p < 0.05). After the application of RF-HPMC solution the mean thinnest corneal pachymetry (TCP) increased to 412.89 ± 26.94 μm. Statistically significant increase was observed in TCP after saturation with RF-HPMC (p = 0.001). The mean corneal pachymetry before and after UVA irradiation was 419.86 ± 10.41 and 417.47 ± 8.25 μm, respectively (p > 0.05).ConclusionsIsotonic RF-HPMC lead to a significant increase in intraoperative mean TCP. RF-HPMC seems to be a favorable riboflavin option in keratoconus patients with thin corneas.     

Evaluation of a new nomogram for Ferrara ring segment implantation in keratoconus

AIM: To evaluate the short-term clinical outcomes of Ferrara rings in keratoconus using an optimized nomogram developed after several years of research and retrospective analysis of clinical data. METHODS: This prospective longitudinal non-comparative clinical trial evaluated 88 eyes of 88 patients (age 18-62y) with keratoconus diagnosis from two Spanish centers. Ferrara ring segment (AJL Ophthalmic) implantation was performed in all cases, using the mechanical procedure in 25 eyes (28.4%) and a femtosecond laser-assisted procedure in 63 eyes (71.6%). The ring segments implanted in each case were selected using a new optimized nomogram that considered variables such as anterior corneal asphericity and astigmatism or the discrepancy among astigmatism and coma orientations. Visual, refractive, corneal topographic, aberrometric, and pachymetric changes after surgery were evaluated during a 3-month follow-up. RESULTS: The implants induced a significant refractive change as well as an improvement in uncorrected (UDVA) and corrected distance visual acuity (CDVA; P<0.001). Postoperative CDVA of 0.10 logMAR or better was achieved in 28.4% and 46.5% of eyes, respectively. Two eyes (2.3%) lost two or more lines of CDVA whereas a total of 53.5% of eyes gained lines of CDVA. A significant central anterior and posterior corneal flattening was induced (P≤0.003), with a significant reduction of anterior (P<0.001) and posterior corneal astigmatisms (P=0.048), and a change in anterior asphericity (P<0.001). Total primary coma (6 mm pupil) change was also statistically significant (preoperative 3.66±3.04 µm vs postoperative 2.33±2.26 µm, P<0.001). No significant differences were found in the effect of ring segments between cases implanted using the mechanical and femtosecond techniques (P≥0.101). CONCLUSION: The implantation of Ferrara rings based on the nomogram evaluated is safe and effective for promoting a visual rehabilitation in keratoconus, with a relevant control of primary coma aberration.     

Topographic characteristics of keratoconus among a sample of Jordanian patients

AIM:To identify topographic characteristics of keratoconus in a Jordanian sample.METHODS:This study characterized 210 corneas affected with keratoconus presenting to Jordan University Hospital. Patients were diagnosed based on clinical examinations and Pentacam imaging. Eyes of males (n=101) were of a similar proportion to females (n=109). All of the 111 patients were affected bilaterally. Ages ranged between 13 and 44y with a mean age of 25.2y.RESULTS:Results revealed significant differences between males and females at the level of the flat curvature power, basement membrane thickness and size of the anterior chamber. Eyes were arranged in three groups based on severity levels:mild, moderate and severe determined by the mean curvature power (Km). Results show that the flat (K1) and steep (K2) curvature powers, corneal asphericity coefficient (QV), thinnest point, pachy apex and basement membrane thickness are significantly different among the three groups, but not the corneal and anterior chamber volumes. Morphological analyses, based on sagittal maps, show no differences in keratometric values between eyes with different sagittal patterns except for the vertical location of the pachy apex relative to the pupil center and the thinnest point. Eyes with the island front elevation map are significantly more affected than eyes with the U shape and the ridge pattern.CONCLUSION:All keratometric values measured except for corneal and anterior chamber volumes vary significantly with disease severity. The vertical pachy apex location correlates well with severity levels while the horizontal location seems to have no effect. Our study also indicates that front elevation maps may be a better predictor of the severity of keratoconus than sagittal maps.     

A new, pachymetry-based approach for diagnostic cutoffs for normal, suspect and keratoconic cornea

Purpose

To analyze whether an association exists between keratometric and pachymetric changes in the cornea, and whether it can be used to create pachymetric cutoff criteria secondary to keratometric criteria.

Methods

In this cross-sectional study, 1000 candidates presenting to the refractive surgery services of a tertiary care hospital underwent bilateral Orbscan IIz (Bausch and Lomb) assessment along with other ophthalmic evaluation.

Results

Stepwise regression analysis-based models showed that simulated keratometry (simK) astigmatism was significantly predicted by the minimum corneal thickness (MCT) and difference between central and MCT (δCT), mean SimK by the MCT and δCT, and maximum keratometry in the central 10-mm zone by the MCT and δCT (P<0.001). The mean MCT values were 542.5±39.6, 539.9±39.2, 524.2±49.5, and 449.3±73.7 μm for flatter normal (<44 D), steeper normal (≥44 D), keratoconus suspect and keratoconic eyes, respectively (P<0.001). The mean differences between central corneal thickness and MCT (δCT) were 12.2±7.1 μm, 12.4±7.4 μm, 14.4±8.9 μm and 23.2±10.1 μm for the flatter normal, steeper normal, keratoconus suspect, and keratoconic eyes, respectively (P<0.001). Mean and 2SD cutoff were used to suggest that a cornea having MCT<461 μm or δCT>27 μm has only a 2.5% chance of being normal and not a keratoconus suspect or worse.

Conclusion

Pachymetric diagnostic cutoffs can be used as adjuncts to the existing topographic criteria to screen keratoconus suspect and keratoconic eyes.     

Safety and efficacy of repeated crosslinking assisted by transepithelial double-cycle iontophoresis in keratoconus progression after primary corneal crosslinking

ObjectivesTo evaluate the safety and efficacy of repeated corneal collagen crosslinking assisted by transepithelial double-cycle iontophoresis (DI-CXL) in the management of keratoconus progression after primary CXL.MethodsA retrospective analysis was conducted in the patients who underwent repeated CXL between 2016 and 2018. These patients were treated with DI-CXL if keratoconus progression was confirmed after primary CXL. Scoring of ocular pain and corneal epithelial damage, visual acuity, corneal tomography, in vivo corneal confocal microscopy (IVCM) was performed before and at 3, 6, 12, and 24 months after DI-CXL.ResultsOverall, 21 eyes of 12 patients (mean age 17.3 ± 1.9 years) were included in this study. Before DI-CXL, an average increase of 4.26 D in K_max was detected in these patients with a mean follow-up interval of (23.0 ± 13.7) months. After DI-CXL, corneal epithelial damage rapidly recovered within days. Visual acuity remained unchanged with follow-up of 24 months. When compared to baseline, significant decreases were observed in K_max (at 3 months) and K2 (at 3 and 6 months) after DI-CXL. Corneal thickness of thinnest point significantly decreased at 3 months postoperatively. When compared to baseline, no significant differences were found in any of the refractive or tomographic parameters at 12 and 24 months. IVCM revealed trabecular patterned hyperdense tissues after DI-CXL in the anterior stroma at the depth of 200 μm or more. No corneal infiltration or persistent epithelial defect was recorded after DI-CXL.ConclusionDI-CXL is safe and effective as a good alternative in stabilizing keratoconus progression after primary CXL.Subject terms: Corneal diseases, Outcomes research     

Comparative evaluation of rotational stability of toric IOLs with four-eyelet vs two-eyelet capsular tension rings in eyes with high myopia

AIM:To compare the rotational stability of Toric intraocular lens(IOLs)implantation combined with foureyelet or two-eyelet capsular tension rings(CTRs)in eyes with high myopia and cataract.METHODS:This prospective randomized controlled interventional study in cluded 33 eyes which had preoperative corneal astigmatism≥1.5 D and ocular axial length≥25.5 mm.These eyes were randomly divided into two groups to undergo phacoemulsification and toric IOL implantation with either four-eyelet CTR implantation(group A,n=16)or two-eyelet CTR implantation(group B,n=17).Uncorrected visual acuity(UCVA),best-corrected visual acuity(BCVA),phoropter examination results,and toric IOL rotation degrees were tested 6 mo after the surgery.RESULTS:In both groups,the toric IOL was in the capsular sac 6 mo after surgery.The difference between the two groups in terms of visual outcome was not found to be statistically significant(P>0.05)at a follow-up of 6 mo.The mean residual astigmatism values were 0.56±0.22 D and 0.92±0.24 D in A and B groups,respectively(P<0.001).The mean rotation degree of IOL was 1.00°±0.73°in group A and 3.53°±1.46°in group B(P<0.001).CONCLUSION:In cataract patients with high myopia and astigmatism,four-eyelet CTR can effectively increase the rotation stability of toric IOLs,achieving the desired goal of correcting corneal astigmatism.     

A cross-sectional study to determine the normal corneal epithelial thickness in Indian population using 9-mm wide optical coherence tomography scans

Purpose:To study the corneal epithelial thickness with 9-mm scans of optical coherence tomography in normal Indians with appropriate representation of all age groups.Methods:This was a cross-sectional observational study. 263 patients were divided into the age groups 5–20 years, 21–35 years, 36–50 years and more than 51 years were recruited for the study. All patients underwent a detailed ophthalmic examination. Patients found to have any ocular surface or intraocular disease condition (except cataract and refractive error), or who had undergone any ophthalmic surgery in the past, or had corneal topography changes suggestive of corneal ectasias (screened in patients with astigmatism more than 3 diopters) or had been continuously using any topical medication in either eye for a period of 3 months or more with the last instillation being within 1 month of inclusion in the study were excluded. All subjects underwent corneal epithelial thickness measurement with anterior segment optical coherence tomography (AS-OCT) on the Avanti OCT (Model RTVueXR1002, Optovue, USA). The corneal epithelial thickness (CET) data from 25 sectors in each eye were analyzed.Results:263 right and left eyes of 263 patients were analyzed in the study. Mean CETs in the central 2 mm zone were 54.13 ± 4.51 μm and 54.37 ± 3.75 μm for the right and left eyes, respectively. The superior peripheral sectors and inferior paracentral sectors were the thinnest and the thickest sectors, respectively, in both eyes.Conclusion:CET parameters for Indian eyes are comparable to those reported from racially distinct and geographically distant study subjects.     

角膜缘保护技术在经上皮角膜交联术中的应用效果

目的:评估经上皮角膜交联(Epi-on CXL)术中采用角膜缘保护技术治疗圆锥角膜的临床应用效果。方法:前瞻性临床研究。选取2019-01/12我院收治拟行Epi-on CXL手术的双眼进展期圆锥角膜患者15例30眼,将右眼15眼纳入试验组,术中采用角膜缘保护技术;左眼15眼纳入对照组,术中不采用角膜缘保护技术。比较两组患眼术前和术后最佳矫正远视力、散光度、角膜曲率Sim-K平均值(Km)、角膜最薄点厚度、泪膜破裂时间及术后不适感、角膜上皮愈合时间的差异。结果:与术前相比,术后3mo时两组最佳矫正远视力、散光度均改善(P<0.05),术后角膜最薄点厚度逐渐减小(P<0.05),术后3mo内泪膜破裂时间变短(P<0.05),但两组之间最佳矫正远视力、散光度、Km、角膜最薄点厚度、泪膜破裂时间、术后不适感方面均无差异(P>0.05),且试验组术后角膜上皮愈合时间比对照组短(3.20±0.56d vs 3.73±0.96d,P=0.041)。结论:角膜缘保护技术能够缩短Epi-on CXL术后角膜上皮愈合时间,初步证实了该技术在Epi-on CXL手术中应用的可行性。     

Automated Keratoconus Detection Using Height Data of Anterior and Posterior Corneal Surfaces

Purpose

To develop a keratoconus detection algorithm using the corneal topographic data of the anterior and posterior corneal surfaces.

Methods

Topographic measurements of the cornea were made with a slit-scanning corneal topographer. We examined 120 subjects (165 eyes); keratoconus patients and keratoconus suspect patients comprised the keratoconus group, and post-photorefractive keratectomy patients, with-the-rule astigmatism patients, and controls without disease comprised the nonkeratoconus group. Two variables of the anterior corneal surface, two variables of the posterior corneal surface, and one corneal thickness variable were obtained by applying the Fourier harmonic decomposition formula. By performing a logistic regression analysis with a training set to differentiate the keratoconus group from the nonkeratoconus group, the Fourier-incorporated keratoconus detection Index (FKI) was created. The validity of the FKI was determined by using independent validation sets.

Results

The FKI distinguished the keratoconus group from the nonkeratoconus group with 96.9% sensitivity and 95.4% specificity in the validation set.

Conclusions

A newly developed automated keratoconus classifier can be used to screen keratoconic patients. The index is based on information obtained by Fourier analysis from not only the anterior corneal surface but also from the posterior corneal surface and corneal thickness.?Jpn J Ophthalmol 2006;50:409–416 © Japanese Ophthalmological Society 2006     

傅里叶域光学相干断层扫描仪测量角膜上皮厚度参数鉴别早期圆锥角膜

目的:探讨傅里叶域光学相干断层扫描仪(FD-OCT)测量角膜上皮厚度参数在圆锥角膜早期诊断中的价值。方法:回顾性对照研究。选取2015-01/2020-10于苏州大学附属第一医院就诊的早期圆锥角膜患者55例62眼,选取同期接受近视激光手术治疗的屈光不正患者110例110眼作为对照组。采用FD-OCT测量获得以瞳孔中心7mm直径范围的角膜上皮层厚度参数、以瞳孔中心9mm直径范围25个分区的角膜上皮层平均厚度值及角膜全层平均厚度值,比较各参数值在早期圆锥角膜组及对照组的差异,对有差异的参数分析诊断价值。结果:早期圆锥角膜组Min_-e值较对照组显著减小,Std.Dev值、Max-Min_-e值、Max_-e值较对照组显著增大(均P<0.001)。Std.Dev值、Max-Min_-e值对早期圆锥角膜诊断效能较高(AUC=0.937、0.928),Max_-e值、Min_-e值诊断效能中等(AUC=0.871、0.797)。25个分区角膜上皮厚度分析,早期圆锥角膜组内...     

Development of unilateral corneal ectasia after PRK with ipsilateral preoperative forme fruste keratoconus

PURPOSE: To describe clinical and topographic features of keratectasia after photorefractive keratectomy (PRK) in a patient with abnormal preoperative topography. METHODS: A 25-year-old man underwent uneventful bilateral PRK for moderate myopia of -5.75 -1.75 x 95 in the right eye and -7.50 -1.25 x 80 in the left eye with best spectacle-corrected visual acuity (BSCVA) of 20/25 in both eyes. Preoperative corneal thickness was 500 microm in the right eye and 460 microm in the left eye. The total calculated ablation depth was 70 microm in the right eye and 100 microm in the left eye. Preoperative corneal topography revealed forme fruste keratoconus in the right eye with an inferior-superior ratio of 4. RESULTS: Five years postoperatively, the patient developed unilateral inferior keratectasia in the right eye with refraction of +0.50 -5.50 x 90, BSCVA of 20/100, and central corneal thickness of 481 microm with inferior corneal thickness of 374 microm. CONCLUSIONS: This case report adds to the growing body of evidence in the ophthalmic literature suggesting that patients with preoperative forme fruste keratoconus or early keratoconus may develop clinically significant progression of corneal ectasia after PRK.     

Combined 23-gauge microincisonal vitrectomy surgery and phacoemulsification with AcrySof toric intraocular lens implantation: a comparative study

Aim

To compare AcrySof toric intraocular lens (IOL) and non-toric IOL in patients who had combined 23-gauge microincisional vitrectomy surgery (MIVS) and phacoemulsification for vitreoretinal diseases and cataract with pre-existing corneal astigmatism.

Methods

This is a prospective comparative study comprised of 30 patients (30 eyes) who had combined 23-gauge MIVS and phacoemulsification for vitreoretinal diseases and cataract with pre-existing regular corneal astigmatism greater than 1 diopters (D). In all, 15 eyes had AcrySof toric IOL (Alcon Laboratories) and 15 eyes had non-toric IOL (Akreos AO MI60; Bausch & Lomb) implantation. Main outcome measures were uncorrected visual acuity (UCVA), refractive cylinder, surgically induced astigmatism (SIA), and IOL misalignment during 6 months.

Results

The mean UCVA of the toric IOL group was better than the non-toric IOL group at postoperative months 1, 3, and 6 (P<0.001, respectively). The mean absolute residual refractive cylinder of the toric IOL group at postoperative week 1, and months 1, 3, and 6 was less than the non-toric IOL group (P=0.008, <0.001, <0.001, and <0.001, respectively). There was no difference in the mean SIA between the two groups (P>0.05, respectively). The mean toric IOL axis rotation was 3.52±2.75°, which was within 5° in 66.7% of the toric IOL group and within 10° in 100%.

Conclusions

Combined 23-gauge MIVS and phacoemulsification with AcrySof toric IOL implantation is an effective method of correcting vitreoretinal diseases and cataract and pre-existing corneal astigmatism, and the toric IOL showed good rotational stability, even in vitrectomized eyes for 6 months.     

Postoperative astigmatic outcomes based on the haptic axis of intraocular lenses inserted in cataract surgery

Purpose

This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery.

Methods

Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the inserted IOL was at 180° or 90°. For ATR patients, the outcomes were analyzed according to the three types of IOLs.

Results

There was no difference in corneal astigmatism, but WTR patients with a 180° haptic axis of the inserted IOL and ATR patients with a 90° hepatic axis of the inserted IOL had a significant decrease in postoperative refractive astigmatism (p < 0.05). The changes in ATR astigmatism according to the IOL type were more effective in single-piece acrylic IOLs than in the three-piece polymethylmethacrylate haptic IOL group.

Conclusions

Insertion of the IOL at the 180° haptic axis in WTR patients and at 90° in ATR patients during cataract surgery may have an effect in reducing pre-existing astigmatism. This observed effect was not consistent among the different types of IOLs.     

Evaluation of corneal topography and tomography in fellow eyes of unilateral keratoconus patients for early detection of subclinical keratoconus

Purpose:To analyse topographic and tomographic changes in fellow eyes of unilateral keratoconus patients by comparing them with normal eyes.Methods:This five-year retrospective observational comparative case study included 15 advanced keratoconus eyes of unilateral keratoconus (KCN group), 15 normal fellow eyes of unilateral keratoconus (Fellow eye group) and 34 eyes of normal refractive surgery candidates (Normal group). Topographic and tomographic data, data from enhanced elevation maps, and keratoconus indices were measured in all study eyes using Pentacam. Receiver operating characteristic (ROC) curves were used to evaluate the area under the curve (AUC), sensitivity and specificity of each parameter and identify cut-off points in discriminating between the fellow and normal eyes.Results:Corneal thickness at the apex (CTA, P = 0.001) and at the thinnest point (CTT, P < 0.001), corneal volume (CV, P = 0.007), Belin/Ambrosio Enhanced Ectasia Display (BAD) - thinnest point (Dt, P = 0.002) and thinnest point displacement (Da, P = 0.002) were significantly lower in the fellow group compared to eyes of normal subjects. On ROC curve analysis, the most efficient distinguishing indices between the fellow group and normal controls were BAD - overall D value (AUC = 0.859), Dt (AUC =0.827), Da (AUC = 0.789) followed by pachymetric progression index maximum (AUC = 0.741).Conclusion:BAD-D value and pachymetric progression index could be useful in detecting the earliest form of subclinical keratoconus. However, every single parameter alone is not enough to detect early changes; a combination of different data is required to distinguish subclinical keratoconus.