Optimized Artificial Intelligence for Enhanced Ectasia Detection Using Scheimpflug-Based Corneal Tomography and Biomechanical Data.

PURPOSE: To optimize artificial intelligence (AI) algorithms to integrate Scheimpflug-based corneal tomography and biomechanics to enhance ectasia detection. DESIGN: Multicenter cross-sectional case-control retrospective study. METHODS: A total of 3886 unoperated eyes from 3412 patients had Pentacam and Corvis ST (Oculus Optikgeräte GmbH) examinations. The database included 1 eye randomly selected from 1680 normal patients (N) and from 1181 "bilateral" keratoconus (KC) patients, along with 551 normal topography eyes from patients with very asymmetric ectasia (VAE-NT), and their 474 unoperated ectatic (VAE-E) eyes. The current TBIv1 (tomographic-biomechanical index) was tested, and an optimized AI algorithm was developed for augmenting accuracy. RESULTS: The area under the receiver operating characteristic curve (AUC) of the TBIv1 for discriminating clinical ectasia (KC and VAE-E) was 0.999 (98.5% sensitivity; 98.6% specificity [cutoff: 0.5]), and for VAE-NT, 0.899 (76% sensitivity; 89.1% specificity [cutoff: 0.29]). A novel random forest algorithm (TBIv2), developed with 18 features in 156 trees using 10-fold cross-validation, had a significantly higher AUC (0.945; DeLong, P < .0001) for detecting VAE-NT (84.4% sensitivity and 90.1% specificity; cutoff: 0.43; DeLong, P < .0001) and a similar AUC for clinical ectasia (0.999; DeLong, P = .818; 98.7% sensitivity; 99.2% specificity [cutoff: 0.8]). Considering all cases, the TBIv2 had a higher AUC (0.985) than TBIv1 (0.974; DeLong, P < .0001). CONCLUSIONS: AI optimization to integrate Scheimpflug-based corneal tomography and biomechanical assessments augments accuracy for ectasia detection, characterizing ectasia susceptibility in the diverse VAE-NT group. Some patients with VAE may have true unilateral ectasia. Machine learning considering additional data, including epithelial thickness or other parameters from multimodal refractive imaging, will continuously enhance accuracy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Efficacy and safety after posterior chamber Implantable Collamer Lens implantation according to preoperative anterior chamber depth: Short-term comparative study.

PURPOSE: To compare visual, refractive, and safety outcomes of posterior chamber Implantable Collamer Lens (ICL) implantation for the correction of myopia according to the preoperative anterior chamber depth (ACD). METHODS: Retrospective, comparative study, patients submitted to implantation of myopic posterior-chamber phakic Implantable Collamer Lens (ICL), model V4C/V5, minimum follow-up of 12 months; two groups were created: Group 1 (ACD 2.80 to 2.99 mm) and Group 2 (ACD equal to or greater than 3.00 mm). The parameters evaluated were uncorrected and corrected visual acuity, subjective refraction, efficacy and safety index, predictability, endothelial cell density, central vault, anterior chamber angle and postoperative complications. A total of 558 eyes from 298 patients were evaluated: 111 eyes (19.9%) in group 1 and 447 eyes (80.1%) in group 2. RESULTS: At 12 months, the efficacy index was similar in both groups (p = 0.264); the safety index was higher in group 1 (p = 0.031); the mean central Vault was significantly lower in group 1 (212.8 vs 410.6 µm; p < 0.001). Respectively, 93 (83.8%) and 366 (84.1%) eyes were within ±0.50 D of targeted refraction. Anterior chamber angle significantly decreased during follow-up in both groups (p < 0.001; p < 0.001). Intraocular pressure did not change significantly (p = 0.310 and p = 0.446, respectively). There were no significant differences in endothelial cell density loss (p = 0.278) or in the rate of complications observed (p = 0.733). CONCLUSIONS: ICL implantation is an effective and safe procedure in eyes with shallow anterior chambers, with visual and refractive results and complication rates identical to those obtained in deeper anterior chambers.

Efficacy and Safety After Toric Posterior Chamber Implantable Collamer Lens and Toric Iris-Fixated Foldable Phakic Intraocular Lens for Myopic Astigmatism.

PURPOSE: To compare visual, refractive, and safety outcomes of toric posterior chamber Implantable Collamer Lens (T-ICL) (STAAR Surgical) and toric iris-fixated foldable phakic intraocular lens (IOL) (T-Artiflex; Ophtec BV) implantation for the correction of myopic astigmatism. METHODS: This retrospective cohort study included 312 eyes of 312 patients who had phakic IOL implantation for myopic astigmatism. Two groups were defined: 205 eyes that underwent T-ICL implantation and 107 eyes that underwent T-Artiflex implantation. Safety, efficacy, and predictability outcomes were evaluated preoperatively and at 12 months postoperatively. Refractive and corneal astigmatic vector analysis were performed using the Alpins method. RESULTS: One year postoperatively, uncorrected distance visual acuity was 0.05 ± 0.18 (T-ICL) and 0.10 ± 0.16 (T-Artiflex) logMAR, with efficacy indexes of 1.16 ± 0.27 and 1.05 ± 0.31, respectively (P < .001). Safety indexes were 1.28 ± 0.30 and 1.21 ± 0.31, respectively (P = .04). Spherical equivalent was within ±0.50 diopters (D) of emmetropia in 165 (80.5%) and 88 (82.2%) eyes, respectively. Refractive astigmatic analysis showed an index of success of 0.28 ± 0.33 (T-ICL) and 0.31 ± 0.26 (T-Artiflex) (P = .07). Surgically induced corneal astigmatism was 0.48 ± 0.74 and 0.81 ± 0.61 D, respectively (P < .001). Mean endothelial loss was 1.11% and 2.05%, respectively (P = .42). Six (2.9%) eyes in the T-ICL group and 1 (0.9%) eye in the T-Artiflex group had phakic IOL repositioning due to significant misalignment. No vision-threatening complications occurred. CONCLUSIONS: Both the T-ICL and T-Artiflex groups showed high visual and refractive efficacy with a good safety profile for the correction of myopic astigmatism. T-ICL implantation demonstrated significantly better efficacy and safety indexes after 12 months. Vector analysis showed similar refractive astigmatic correction in both groups, but T-Artiflex implantation revealed higher surgically induced corneal astigmatism. [J Refract Surg. 2022;38(6):339-347.].

Intraocular Lens Position and Anterior Chamber Parameters Evaluation After Nd:YAG Laser Posterior Capsulotomy for Posterior Capsular Opacification Using Anterior Segment Swept-Source Optical Coherence Tomography.

PURPOSE: To evaluate the effect of neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy on intraocular lens (IOL) position and anterior segment parameters with a new swept-source anterior segment optical coherence tomography (AS-OCT) device (Anterion®, Heidelberg Engineering GmbH). PATIENTS AND METHODS: A total of 50 eyes from 50 consecutive patients were included. All patients had visually significant posterior capsular opacification (PCO) after uneventful phacoemulsification surgery with manual capsulorhexis and single-piece C-loop acrylic IOL implantation (AcrySof® SA60AT) and were treated with Nd:YAG laser. Anterior segment images were captured with Anterion® in non-dilated conditions before and one month after the procedure. In the "Metrics App", we collected data of the anterior chamber angle (ACA) 3 and 9 o'clock, the anterior chamber depth (ACD), the anterior chamber volume (ACV), and the central corneal thickness (CCT). We also collected demographic and clinical data [age, gender, months from surgery to Nd: YAG capsulotomy, pre- and post-capsulotomy corrected distance visual acuity (CDVA) and spherical equivalent, and axial length]. RESULTS: We did not find a statistically significant difference in ACD after the Nd:YAG capsulotomy (3.96 ± 0.55 vs 3.97 ± 0.55 mm, p = 0.10). In 28 patients, we noted a backward movement of the IOL; in the remaining 22, the IOL moved forward or did not change at all. We did not observe significant changes in ACA at the 3 and 9 o'clock reference points, ACV, or CCT. There was an improvement in CDVA after the procedure (0.37 ± 0.21 vs 0.12 ± 0.27 logMAR, p = 0.015), without statistically significant differences in SE (-0.15 ± 0.84 vs -0.25 ± 0,93, p = 0.42). Axial length was not correlated with ACD variations after the procedure (p = 0.67). CONCLUSION: Our results show that Nd:YAG laser capsulotomy does not change the axial position of a single-piece C-loop acrylic IOL inside the capsular bag, as well as other anterior chamber parameters.

Clinical Validation of the Automated Characterization of Cone Size and Center in Keratoconic Corneas.

PURPOSE: To evaluate an automated method for detecting the cone shape characteristics and to assess the cornea specialists' subjective variability of these measures using different maps. METHODS: Topographic images of the anterior and posterior surface of each eye were presented to 12 clinicians in two different types of map: tangential curvature and relative elevation to the best-fit sphere. They were asked to mark the cone center and its boundaries in the two maps without knowing that they belonged to the same patient. The results between the maps were compared to assess the subjective variability dependent on the map type and the automated method was compared against both estimations to assess its accuracy. RESULTS: Considering the results of anterior and posterior surfaces, there was low agreement between the cone center estimations using different types of maps for 10 of the 12 cases (P < .05), whereas the comparison between the automated method and the two map estimations did not show differences in 11 of the 12 cases (P > .05). There was high variability, up to 55%, among clinicians' estimations of the cone area. The results of the automated method were within the range of the expert's estimations. CONCLUSIONS: An objective, mathematically derived method of determining morphological dimensions of the cone was consistent with clinicians' evaluations. Although there was high variability among the experts' subjective estimates, which were highly influenced by the type of map, the objective method provided a reliable evaluation of the keratoconus shape independent of maps or color scale. [J Refract Surg. 2021;37(6):414-421.].

Posterior chamber collamer phakic intraocular lens implantation: Comparison of efficacy and safety for low and moderate-to-high myopia.

PURPOSE: To compare visual, refractive and safety outcomes of central-hole posterior chamber collamer phakic intraocular lens implantation for low and moderate-to-high myopia. SUBJECTS/METHODS: This retrospective cohort study included 338 eyes submitted to posterior chamber collamer phakic intraocular lens implantation that completed a 12-month postoperative follow-up. Two groups were defined depending on preoperative spherical equivalent: group 1 comprised 106 eyes with manifest spherical equivalent of -6.00 D or less; group 2 comprised 232 eyes with manifest spherical equivalent higher than -6.00 D. Effectiveness, predictability, stability and safety outcomes were compared preoperatively and at 1, 6 and 12 months postoperatively. RESULTS: At 1-year postoperative, uncorrected and corrected visual acuities were 0.02 ± 0.17 and -0.01 ± 0.12 logMAR (group 1) and 0.04 ± 0.20 and 0.01 ± 0.16 logMAR (group 2), with an efficacy index of 1.05 ± 0.17 and 1.17 ± 0.28. Respectively, 92 (86.8%) and 199 (85.8%) eyes were within ±0.50 D of targeted refraction, and postoperative manifest refraction changes were -0.07 ± 0.25 D and -0.07 ± 0.35 D. Intraocular pressure did not change significantly. The mean rate of endothelial cell loss was 1.12% and 1.10%, respectively. One case of anterior subcapsular cataract (group 2) was observed. ICL exchange occurred in one case (group 1) and three cases (group 2). No vision-threatening complications were reported. CONCLUSION: The posterior chamber collamer phakic intraocular lens implantation demonstrated high visual and refractive efficacy with an excellent safety profile for the correction of both low and moderate-to-high myopia, revealing equivalent 1-year outcomes regardless of the degree of preoperative myopia.

Topography/wavefront-guided photorefractive keratectomy combined with crosslinking for the treatment of keratoconus: preliminary results.

PURPOSE: To evaluate the clinical outcomes of topography/wavefront-guided (TWFG) photorefractive keratectomy (PRK) using a new high-definition aberrometer combined with epithelium-off crosslinking (CXL-Plus). SETTING: Centro Oculistico Bresciano, Brescia, Italy. DESIGN: Prospective case series study. METHODS: Patients with grade I or II keratoconus, according to the Amsler-Krumeich classification, were included in this prospective case series. All cases underwent TWFG PRK using the VISX STAR S4 IR excimer laser and the new iDesign 2.0 system, followed by accelerated epithelium-off CXL. Visual, refractive, ocular aberrometric, and safety outcomes were evaluated during a 6-month follow-up. RESULTS: Thirty-five eyes of 19 patients were included. A significant improvement was observed in the uncorrected and corrected distance visual acuities (P < .001). Manifest sphere and cylinder were reduced significantly (P ≤ .001), with a total of 20 eyes (57%) and 30 eyes (86%) having a postoperative spherical equivalent within ±0.50 and ±1.00 diopter, respectively. Most corneal irregularity indexes and the level of ocular higher-order aberrations, primary coma, and trefoil (P < .05) were significantly reduced postoperatively. No significant corneal haze or safety issues were observed. CONCLUSIONS: TWFG PRK, using the iD2 system with simultaneous CXL, regularized the cornea by correcting the spherocylindrical error and minimizing the amount of higher-order aberrations in mild-to-moderate keratoconus.

Five-year long-term outcomes of intrastromal corneal ring segment implantation using the manual technique for keratoconus management.

PURPOSE: To evaluate the long-term effectiveness, safety, and stability of Ferrara-type intrastromal corneal ring segments (ICRS) by manual surgery implantation in patients with keratoconus. SETTING: Ophthalmology Department, Hospital de Braga, Braga, Portugal. DESIGN: Retrospective cohort study. METHODS: This study included 124 eyes that had ICRS implantation using the manual technique with a follow-up of 5 years. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), subjective refraction, keratometry, aberrometry, and pachymetry maps were evaluated preoperatively and at 6 months, 1 year, and 5 years postoperatively. A secondary analysis of all variables was performed comparing 2 subgroups of patients: a group younger than 30 years and a group of 30 years or older. RESULTS: At 5 years, both mean UDVA and CDVA improved significantly (P < .0001) from a preoperative value of 0.91 ± 0.36 to 0.46 ± 0.32 logMAR and 0.40 ± 0.27 to 0.22 ± 0.20 logMAR, respectively. Spherical equivalent, refractive cylinder, and all topography values significantly decreased postoperatively (P < .0001). No regression was observed in any visual or topographic parameter during the entire follow-up. Regarding the subgroup analysis, both younger and older patients demonstrated similar and stable results from the preoperative to the 5-year visit, except for minimum pachymetry value change over time. CONCLUSIONS: Ferrara-type ICRS implantation significantly improved visual acuity, refractive error, and topographic values; the improvement was stable throughout a 5-year follow-up period. This study confirms that ICRS implantation surgery for keratoconus is a stable procedure in a long-term follow-up, regardless of the preoperative patient's age.

Dysfunctional lens syndrome: a prospective review / Síndrome do cristalino disfuncional: uma revisão prospectiva

ABSTRACT The term dysfunctional lens syndrome has gained acceptance in the field and encompasses natural changes due to aging of crystalline lens. The evolution of diagnostic devices has been a key factor in better staging, understanding and characterizing of these degenerative changes. Even with these technological advances and the use of subjective classifications, such as the classic Lens Opacities Classification System, an objective staging of early dysfunctional lens syndrome has yet to be established. Ocular wavefront aberrometry and objective scatter index, associated with Scheimpflug backscatter densitometry, have proven instrumental in detecting early dysfunctional lens syndrome. Staging of early dysfunctional lens syndrome has been proposed in the literature, but no classification has been recognized worldwide. The purpose of this literature review is to assess the current state of dysfunctional lens syndrome from a technological perspective and propose a new staging system to assist surgeons in making surgical decisions.

RESUMO O termo "síndrome disfuncional do cristalino" tem sido mais aceito na área e engloba mudanças naturais devido ao envelhecimento do cristalino. A evolução dos dispositivos diagnósticos tem sido fator fundamental para melhor estadiamento, compreensão e caracterização dessas alterações. Mesmo com esses avanços tecnológicos e o uso de classificações subjetivas, como o Lens Opacities Classification System , um estadiamento objetivo da síndrome disfuncional do cristalino precoce ainda não foi estabelecido. A aberrometria ocular total e o índice de superfície ocular, associado à densitometria de Scheimpflug, mostraram-se instrumentais na detecção da síndrome disfuncional do cristalino precoce. Embora estadiamentos precoces de síndrome disfuncional do cristalino tenham sido propostos na literatura, nenhum foi reconhecido mundialmente até o momento. O objetivo desta revisão de literatura é avaliar o estado atual da síndrome disfuncional do cristalino a partir de uma perspectiva tecnológica, e propor um novo sistema de estadiamento para auxiliar os cirurgiões na tomada de decisões cirúrgicas.

Outcomes Comparison Between Wavefront-Optimized and Topography-Guided PRK in Contralateral Eyes With Myopia and Myopic Astigmatism.

PURPOSE: To compare clinical outcomes between topography-guided customized ablation treatment (TCAT) and wavefront-optimized (WFO) photorefractive keratectomy (PRK) in fellow eyes of myopic patients. METHODS: Forty-six eyes of 23 patients who underwent PRK were included. WFO ablation was performed in one eye (WFO group) and TCAT in the fellow eye (TCAT group). The customized treatment plan was based on the Topolyzer Vario topography system (Alcon Laboratories, Inc) data. The patients were observed for 12 months after the procedure. RESULTS: One year after the surgery, there was no significant difference in the manifest refraction spherical equivalent, sphere, or cylinder variables between the two groups (P > .05). In both groups, 96% of eyes achieved an uncorrected distance visual acuity of 20/20 or better at 12 months postoperatively. Accuracy, safety, and efficacy of the refractive and visual outcomes were similar in the two groups. The postoperative higher order aberrations magnitude was lower in the TCAT group, but this was not statistically significant (P > .05). During the 12-month follow-up, no patient described any symptoms related to glare, halos, or starbursts in either eye. Other postoperative complications, such as infection or cor-neal infiltrates, did not occur in either group. CONCLUSIONS: TCAT and WFO ablations provided similar outcomes after PRK for myopia and myopic astigmatism correction. There were no statistically significant differences in postoperative corneal wavefront analysis. [J Refract Surg. 2020;36(6):358-365.].

Enhanced Ectasia Detection Using Corneal Tomography and Biomechanics.

PURPOSE: To test the accuracy of the Tomographic and Biomechanical Index (TBI) for ectasia detection in an independent population from the original study. DESIGN: Retrospective case-control study. METHODS: Subjects: Patients were grouped according to clinical diagnosis including corneal topography (front-surface curvature): Normal group, including 1 eye randomly selected from 312 patients with normal corneas; Keratoconus group, including 1 eye randomly selected from 118 patients with keratoconus; a nonoperated ectatic eye from 57 patients with very asymmetric ectasia (57 eyes, VAE-E group), and the nonoperated fellow eye with normal topography (57 eyes, VAE-NT group). MAIN OUTCOME MEASURES: The ability of TBI to distinguish normal and ectatic corneas; and comparison with other indexes, including the Belin/Ambrósio Deviation Index (BAD-DI) and the Corvis Biomechanical Index (CBI), considering the areas under receiver operating characteristic curves (AUCs). RESULTS: The AUC of the TBI was statistically higher than all other tested parameters (DeLong, P < .001). Considering all cases, the cut-off value of 0.335 for the TBI provided a sensitivity of 94.4% and a specificity of 94.9% (AUC = 0.988; 95% confidence interval [CI] 0.982-0.995). Considering the VAE-NT group, optimized TBI cut-off value of 0.295 provided a sensitivity of 89.5% and a specificity of 91.0% (AUC = 0.960; 95% CI 0.937-0.983). CONCLUSION: The TBI was more accurate than all parameters tested for differentiating normal from ectatic corneas. The TBI may epitomize ectasia susceptibility and distinguish cases with fruste disease from true unilateral cases among the eyes with normal-topography VAE.

Effect of superior blepharoplasty on tear film: objective evaluation with the Keratograph 5M - a pilot study / Efeito da blefaroplastia superior no filme lacrimal - avaliação objetiva com ceratógrafo 5M - estudo piloto

ABSTRACT Purpose: To evaluate the effect of superior blepharoplasty on the tear film using the corneal topographer Keratograph 5M. Methods: A prospective study was performed of 27 eyes of 14 patients with superior dermatochalasis who underwent superior blepharoplasty between May and June 2016. Conservative upper eyelid blepharoplasty was performed by an en bloc resection of anterior lamellar tissue that included skin, subcutaneous tissue, and the orbicularis oculi muscle. All the eyes were imaged using the noninvasive tear breakup time tools of the Keratograph 5M. The following parameters were recorded in each patient before and 6 weeks after surgery: first noninvasive Keratograph 5M tear breakup time (the time at which the first breakup of tears occurs) and average noninvasive Keratograph 5M tear breakup time (the average time of all breakup incidents). The exclusion criteria were ophthalmological pathology, previous eyelid surgery, use of eye drops, systemic pathology, and medication that interferes with lacrimal tears. Results: The mean age of the patients was 65.1 years (range, 51-84); 86% were female. Student's t-test was used to compare the values of first and average noninvasive Keratograph 5M tear breakup times before and after surgery. The values for first noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were not significantly different (9.04 and 8.71, respectively; p=0.926). The values for average noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were also not significantly different (13.01 seconds and 13.14 seconds, respectively; p=0.835). Conclusions: The results of this pilot study suggest that upper blepharoplasty does not affect tear breakup time according to the objective evaluation of breakup time with the Keratograph 5M.

RESUMO Objetivos: Avaliar o efeito da blefaroplastia superior no filme lacrimal, utilizando o topógrafo de córnea Keratograph 5M. Métodos: Foi realizado estudo prospectivo de 27 olhos de 14 pacientes com dermatocálase superior submetidos à blefaroplastia superior entre maio e junho de 2016. A blefaroplastia palpebral superior conservadora foi realizada por ressecção em bloco de tecido lamelar anterior que incluiu pele, tecido subcutâneo e músculo orbicular do olho. Todos os olhos foram fotografados usando as ferramentas não-invasivas de tempo de ruptura do lacrimal do Keratograph 5M. Os seguintes parâmetros foram registrados em cada paciente antes e 6 semanas após a cirurgia: primeiro tempo não-invasivo de ruptura lacrimal de Keratograph 5M (o tempo em que ocorre o primeiro rompimento dos rasgos) e média não-invasiva do tempo de ruptura lacrimal (tempo médio de todos os incidentes de ruptura). Os critérios de exclusão foram: patologia oftalmológica, cirurgia anterior das pálpebras, uso de colírio, patologia sistêmica e medicação que interfere na ruptura lacrimal. Resultados: A idade média de idade dos pacientes foi de 65,1 anos (variação entre 51-84); 86% eram do sexo feminino. O teste t de Student foi usado para comparar os valores não-invasivos do tempo de ruptura lacrimal do Keratograph 5M e do tempo de ruptura lacrimal não invasivo do mesmo antes e após a cirurgia. Os valores não-invasivos do tempo de ruptura lacrimal do Keratograph 5M avaliados antes e após a cirurgia não foram significativamente diferentes (9,04 e 8,71, respectivamente; p=0,926). Os valores do tempo médio de ruptura lacrimal do Keratograph 5M avaliados antes e após a cirurgia, também não foram significativamente diferentes (13,01 e 13,14 segundos, respectivamente; p=0,835). Conclusão: Os resultados deste estudo piloto sugerem que a blefaroplastia superior não afeta o tempo de ruptura lacrimal de acordo com a avaliação objetiva do tempo de ruptura com o Keratograph 5M.

Effect of superior blepharoplasty on tear film: objective evaluation with the Keratograph 5M - a pilot study.

PURPOSE: To evaluate the effect of superior blepharoplasty on the tear film using the corneal topographer Keratograph 5M. METHODS: A prospective study was performed of 27 eyes of 14 patients with superior dermatochalasis who underwent superior blepharoplasty between May and June 2016. Conservative upper eyelid blepharoplasty was performed by an en bloc resection of anterior lamellar tissue that included skin, subcutaneous tissue, and the orbicularis oculi muscle. All the eyes were imaged using the noninvasive tear breakup time tools of the Keratograph 5M. The following parameters were recorded in each patient before and 6 weeks after surgery: first noninvasive Keratograph 5M tear breakup time (the time at which the first breakup of tears occurs) and average noninvasive Keratograph 5M tear breakup time (the average time of all breakup incidents). The exclusion criteria were ophthalmological pathology, previous eyelid surgery, use of eye drops, systemic pathology, and medication that interferes with lacrimal tears. RESULTS: The mean age of the patients was 65.1 years (range, 51-84); 86% were female. Student's t-test was used to compare the values of first and average noninvasive Keratograph 5M tear breakup times before and after surgery. The values for first noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were not significantly different (9.04 and 8.71, respectively; p=0.926). The values for average noninvasive Keratograph 5M tear breakup time evaluated before and after surgery were also not significantly different (13.01 seconds and 13.14 seconds, respectively; p=0.835). CONCLUSIONS: The results of this pilot study suggest that upper blepharoplasty does not affect tear breakup time according to the objective evaluation of breakup time with the Keratograph 5M.

Topography-Guided Custom Photorefractive Keratectomy for Myopia in Primary Eyes With the WaveLight EX500 Platform.

PURPOSE: To evaluate the outcomes after topography-guided ablation treatment (T-CAT) for the correction of myopia and myopic astigmatism with photorefractive keratectomy (PRK). METHODS: This was a retrospective, non-comparative case series study of 25 patients (40 eyes) with low to moderate myopia with or without astigmatism who underwent topography-guided custom PRK with the Wave-Light EX500 excimer laser platform (Alcon Laboratories, Inc., Fort Worth, TX). The customized treatment plan was based on Topolyzer Vario topography system (Alcon Laboratories, Inc.) data. The patients were observed for 6 months after the procedure. RESULTS: The surgery significantly reduced the manifest refractive spherical equivalent (MRSE), sphere, and cylinder (P < .05) at 6 months of follow-up. Compared with the preoperative corrected distance visual acuity (CDVA), 8 (20%) and 10 (25%) of 40 eyes gained one or more lines of postoperative uncorrected distance visual acuity at 3 and 6 months, respectively. Only 1 eye presented loss of one line of CDVA at 6 months postoperatively, which was due to delayed epithelial healing. Ten patients (15 eyes) reported symptoms related to dry eye and the vision of 21 patients (17 eyes) fluctuated during the first month. CONCLUSIONS: The T-CAT custom PRK procedure provided good early outcomes for treating patients with low to moderate myopia with or without astigmatism. [J Refract Surg. 2018;34(8):541-546.].

Comparative study of induced changes in effective lens position and refraction after Nd:YAG laser capsulotomy according to intraocular lens design.

PURPOSE: To evaluate and compare the changes in refraction and effective intraocular lens (IOL) position between a plate-haptic IOL and a c-loop single-piece IOL after neodymium-doped yttrium aluminium garnet (YAG) laser posterior capsulotomy. METHODS: In a prospective study, anterior chamber depth and subjective refraction were measured in 110 pseudophakic eyes from 110 patients, before and 1 month after YAG laser capsulotomy. Patients were divided into 2 groups according to the IOL design: group 1 (plate-haptic acrylic hydrophilic AT LISA tri 839MP®) and group 2 (c-loop acrylic hydrophobic single-piece AcrySof® SA60AT). Lens position was obtained through optical coherence biometry (Biograph WaveLight OB820®). RESULTS: YAG laser capsulotomy was performed 37.8±9.8 months after surgery in group 1 and 40.6±8.6 months in group 2 (p=0.125). Significant changes were found in the lens effective position after treatment in the 2 groups. The YAG posterior capsulotomy led to a change of anterior chamber depth in group 1 from 4.03±0.32 mm to 3.86±0.34 mm (p=0.02) and in group 2 from 4.03±0.37 mm to 4.14±0.45 mm (p=0.025). After YAG laser posterior capsulotomy, no significant changes were observed in mean spherical equivalent, sphere or cylinder for both groups (p>0.05). CONCLUSION: YAG laser posterior capsulotomy can induce a significant change in the IOL position according to the IOL type; however, the refractive change after treatment is clinically insignificant.

Predictability of Tunnel Depth for Intrastromal Corneal Ring Segments Implantation Between Manual and Femtosecond Laser Techniques.

PURPOSE: To compare the predictability of intrastromal tunnel depth creation for intrastromal corneal ring segments (ICRS) implantation between manual dissection and femtosecond laser using a high-resolution anterior segment optical coherence tomography (AS-OCT). METHODS: This multicenter study included patients with keratoconus who had Ferrara-type ICRS implantation at Hospital de Braga using manual dissection and at the Fernandez-Vega Ophthalmological Institute using the femtosecond laser technique. The intended depth of implantation was compared to the achieved postoperative ICRS depth of each case, measured using a swept-source AS-OCT (CASIA SS-1000; Tomey Corporation, Nagoya, Japan) at three points (proximal, central, and distal end of the implant). RESULTS: The study included 105 eyes in the manual group and 53 eyes in the femtosecond laser group. The differences of the intended versus the achieved depth were statistically higher in the manual group for all positions measured (Wilcoxon ranked-sum, P < .001). In the manual group, there were significant differences between the mean values of intended and achieved depth after surgery for the three locations measured (Wilcoxon signed-rank, P < .05), whereas there were no significant differences in the femtosecond laser group. In the manual group, the proximal part of the stromal tunnel was significantly shallower (-40.87 ± 69.03 µm) than the central (-25.54 ± 71.00 µm) and distal (-26.52 ± 73.22 µm) parts (Friedman test, P < .05). CONCLUSIONS: ICRS implantation assisted by a femtosecond laser provides a more precise procedure considering dissection depth when compared with the manual dissection technique. Such an advantage may provide more predictable clinical results and safer procedures with the femtosecond laser. [J Refract Surg. 2018;34(3):188-194.].

Dynamic corneal deformation response and integrated corneal tomography.

Measuring corneal biomechanical properties is still challenging. There are several clinical applications for biomechanical measurements, including the detection of mild or early forms of ectatic corneal diseases. This article reviews clinical applications for biomechanical measurements provided by the Corvis ST dynamic non contact tonometer.

Correlation between different Scheimpflug-based lens densitometry analysis and effective phacoemulsification time in mild nuclear cataracts.

PURPOSE: To assess the correlations between preoperative Scheimpflug-based lens densitometry and effective phacoemulsification time (EPT) in age-related nuclear cataracts. DESIGN: Retrospective consecutive study. METHODS: The setting was the Ophthalmology Department, Hospital de Braga, Portugal. The study population included 50 eyes (42 patients) with age-related nuclear cataracts submitted to uneventful phacoemulsification surgery. Different analysis methods of Scheimpflug-based lens densitometry were performed: Pentacam Nucleus Staging (PNS) score with an ordinal scale from 0 to 5 and three-dimensional (3D), linear and region of interest (ROI) methods, which are displayed on an absolute scale (from 0 to 100%). EPT was calculated for the cataract surgery, which was performed by the same surgeon. Correlations between lens densitometry variables and EPT were determined using Pearson or Spearman correlation coefficients according to data normality. RESULTS: There were significant correlations between EPT and average density and maximum density variables derived from the 3D (r = 0.596, p < 0.001; r = 0.632, p < 0.001, respectively) and ROI (r = 0.527, p < 0.001; r = 0.575, p < 0.001, respectively) methods. The average density was the only parameter derived from the linear analysis that showed a significant correlation with EPT (r = 0.293, p = 0.039). The PNS score did not show a significant correlation with EPT (rho = 0.124, p = 0.390). CONCLUSION: The densitometric parameters based on the 3D method showed the highest correlations with EPT. The referred lens densitometric analysis approach may be used in preoperative assessment in order to predict EPT more efficiently in age-related nuclear cataracts.