Visual outcomes of second surgery LASEK following aborted LASIK surgeries due to flap complications

Refractive surgery is designed to minimize the need for glasses and/or contact lenses and is often used for convenience, cosmetic or occupational purposes. The two most common types of laser eye surgery are LASIK and LASEK. During LASIK, the first step is the creation of the corneal flap using either a femtosecond laser or a mechanical microkeratome. The femtosecond laser has been seen to create more uniform flaps that reduce the risk of intraoperative and postoperative flap complications compared to the mechanical microkeratome. The purpose of this study was to investigate the effect on visual outcomes of second surgery LASEK on patients following aborted LASIK surgeries due to Femtosecond laser flap complications. LASIK was performed as planned and the corneal flap was created by the femtosecond laser but could not be lifted when a surgical cut was made. The procedure was aborted and LASEK was performed within a few weeks to attain the desired vision correction. A total of 14 patients were identified over a 6-year period ranging from 2009-2015. Most patients underwent surface ablation within two weeks of the initial aborted procedure. 12 of the 14 patients had a UCVA of 20/20, while the remaining 2 patients had a UCVA of 20/25 at their last postoperative visit. None of the patients required surgical enhancements despite the flap complications and no major postoperative complications were noted in any of the patients. Provided the corneal flap was well centered and there was no evidence of microstriae or epithelial ingrowth, surface ablation LASEK can be performed within a week of the aborted LASIK procedure to minimize discomfort and trauma to the patient. LASEK is associated with a slightly longer healing time but no evidence of corneal or retinal issues were noted in these patients. None of the patients experienced any significant changes in refraction between surgeries and was thus a reliable indicator of refractive stability following the flap complication. No significant differences were noted with delaying the second surgery LASEK as several patients attained 20/20 vision when it was performed within a week. The most common flap complication was the formation of an incomplete flap that could not be lifted. The cause could not be identified

Long-term incidence of dry eyes and visual aberrations after corneal refractive surgery

INTRODUCTION/PURPOSE: Billions of people world wide suffer from refractive errors requiring glasses, contact lenses, or other means of correction to enable them to see better. Many people seeking permanent means to correct their vision consider undergoing corneal refractive laser surgeries (CRLS), photorefractive keratectomy (PRK), laser-assisted subepithelial keratectomy (LASEK), or laser in situ keratomileusis (LASIK). These surgeries have been shown to improve vision, but are not without risks for complications intra-operatively and postoperatively. Few studies have looked at the long-term incidence of postoperative complications such as dry eyes and visual aberrations and the associated preoperative risk factors. It is the aim of this study to examine the long-term incidence of dry eyes and visual aberrations (starbursts, halos, glare) after CRLS, and assess for preoperative risk factors associated with the persistence of these symptoms after surgery. METHODS: This study consisted of 319 patients identified for undergoing PRK, LASEK, or LASIK, at Boston Laser between December 2009 and January 2014. The participants in this study completed a novel online questionnaire consisting of questions to assess dry eye and visual aberration symptoms, and included questions adapted from the Ocular Surface Disease Index (OSDI). Postoperative dry eye symptoms were measured based on the OSDI score and a new dry eye measurement score created for this study's questionnaire. Presence or absence of visual aberration symptoms postoperatively were measured based on a score created for this study and derived from the calculation of the OSDI score. Additionally, a retrospective chart review was conducted of the 319 participants' medical charts to gather and assess for preoperative risk factors related to the long-term incidence of both dry eye and visual aberration symptoms. RESULTS: Our data found a significant association (p 0.05) was found between the novel dry eye score and the preoperative factors, but it did approach significance with two variables, necessitating further investigation: gender and actual ablation. No significance (p >0.05) was found in the association between the preoperative dry eye risk assessment and severity of postoperative symptoms as gathered using the OSDI score. Our data found a significant association (p 0.05) when comparing the difference between mean OSDI, dry eye, and visual aberration scores between participants grouped by years since surgery. DISCUSSION/CONCLUSION: Our data found a significant relationship between long-term dry eye risk after CRLS and preoperative pupil size, flap thickness, and dry eye risk assessment. Similarly the data also displayed a significant association between long-term visual aberration risk after CRLS and greater preoperative cylindrical manifest refraction, flat K, and flap thickness. These findings contribute to the risk factors identified in similar short-term follow-up studies, and support the need for increased research into the risk factors and long-term incidence of dry eyes and visual aberrations after CRLS. While the data showed no significance between participants grouped by years since surgery and reported postoperative symptoms, the OSDI mean scores did approach significance (p = 0.088), suggesting that further research with a greater survey population is required

Risk factors of regression and undercorrection in photorefractive keratectomy: A case-control study

�AIM: To determine risk factors of regression and undercorrection following photorefractive keratectomy (PRK) in myopia or myopic astigmatism. �METHODS: A case-control study was designed in which eyes with an indication for re-treatment (RT) were defined as cases; primary criteria for RT indication, as assessed at least 9mo postoperatively, included an uncorrected distance visual acuity (UDVA) of 20/30 or worse and a stable refraction for more than 3mo. Additional considerations included optical quality symptoms and significant higher order aberrations (HOAs). Controls were chosen from the same cohort of operated eyes which had complete post-operative follow up data beyond 9mo and did not need RT. The cohort included patients who had undergone PRK by the Tissue-Saving (TS) ablation profile of Technolas 217z100 excimer laser (Bausch & Lomb, Rochester, NY, USA). Mitomycin C had been used in all of the primary procedures. �RESULTS: We had 70 case eyes and 158 control eyes, and they were comparable in terms of age, sex and follow-up time (P values:0.58, 1.00 and 0.89, respectively). Pre-operative spherical equivalent of more than -5.00 diopter (D), intended optical zone (OZ) diameter of less than 6.00 mm and ocular fixation instability during laser ablation were associated with RT indications (all P values -5.00 D), smaller OZ (<6.00 mm) and unstable fixation during laser ablation of PRK for myopia and myopic astigmatism were found to be strong predictors of undercorrection and regression. © 2015 International Journal of Ophthalmology (c/o Editorial Office). All Rights Reserved

The effect of postoperative keratometry on visual acuity after corneal refractive laser surgery

PURPOSE: To determine if there is a relationship between eyes with flat corneas (as defined by calculated postoperative keratometry values of <38D) undergoing either LASIK (Laser-assisted in Situ Keratomileusis), LASEK (Laser-assisted Subepithelial Keratectomy), or PRK (Photorefractive Keratectomy) corneal refractive surgery and loss of 1 or more lines of postoperative BCVA, and if there is an advantage to undergoing either LASIK or ASA in eyes meeting flat cornea criteria. METHODS: A retrospective analysis of 191 candidate eyes with calculated postoperative keratometry values <38D were identified and matched by manifest refraction and surgery type to 191 control eyes with calculated postoperative keratometry values ≥38D. Both candidate groups and control groups were further stratified into subgroups based on degree of calculated postoperative keratometry. Candidate subgroups: Subgroup 1a (K<35D), Subgroup 2a (K=35-35.99D), Subgroup 3a (K=36-36.99D), and Subgroup 4a (K=37-37.99D). Control subgroups: Subgroup 1b (K=38-38.99D), Subgroup 2b (K=39-39.99D), Subgroup 3b (K=40-40.99D) and Subgroup 4b (K≥41D). All patients had undergone corneal refractive eye surgery procedures LASIK, LASEK, or PRK at Boston Eye Group/Boston Laser in Brookline MA between December 2008 and November 2016. All LASIK flaps were created using the femtosecond laser IntraLase iFS60 Laser (Abbott Medical Optics Inc.). All surface ablation procedures were performed using the excimer lasers VISX STAR S4 IR Excimer Laser System (Abbot Medical Optics Inc.) or WaveLight EX500 Excimer Laser (Alcon Laboratories Inc.). Visual acuity outcomes measuring preoperative and postoperative BCVA and loss of BCVA were recorded as part of the patient’s medical chart and were statistically analyzed to determine correlations. RESULTS: Our data showed no significant differences between overall candidate (K<38D) and control (K≥38D) group mean preoperative BCVA (p<0.23) or mean postoperative BCVA (p<0.13). A total of 15 out of 191 (7.9%) candidate eyes lost 1 or more lines of BCVA in comparison to 23 total control eyes (12.0%) that lost 1 or more lines of BCVA postoperatively. When evaluating subgroup data, Candidate Subgroup 1a (K<35D) showed a significant (p<0.02) decrease in BCVA when compared to other candidate subgroups. Additionally, Control Subgroup 1b (K=38=38.99D) and Control Subgroup 2b (39-39.99D) showed a significant (p<0.001 and p<0.02 respectively) decrease in BCVA compared to other control subgroups. A total of 231 total candidate and control eyes underwent LASIK and a total of 151 total candidate and control eyes underwent ASA. Overall, 17 out of the 231 (7.4%) eyes undergoing LASIK lost BCVA compared to the 21 out of 151 (13.9%) eyes undergoing ASA that lost BCVA which was significant (p<0.04). CONCLUSION: This study did not find evidence to support that the overall flat cornea group (K<38D) lost postoperative BCVA when compared to a control group of eyes with normal keratometry values. However, our data indicated that when the candidate group was stratified by degree of corneal curvature, patients with very flat corneas (K<35D) may be at increased risk of losing BCVA though further studies are needed. Additionally, eyes undergoing ASA may be at increased risk of losing BCVA though further studies are needed.2018-07-11T00:00:00

Current Challenges and Advances in Cataract Surgery

This reprint focuses on new trials related to cataract surgery, intraocular lens power calculations for cataracts after refractive surgery, problems related to high myopia, toric IOL power calculations, etc. Intraoperative use of the 3D Viewing System and OCT, studies on the spectacle dependence of EDOF, IOL fixation status and visual function, and dry eye after FLAC are also discussed. Proteomic analysis of aqueous humor proteins is also discussed

The role of dry eye disease in cataract and refractive surgery

El síndrome de ojo seco (DED) puede jugar un papel importante en las cirugías oftálmicas con fines refractivos tanto corneales (tratamiento corneal laser) como cristalinianas (cirugía de catarata) pero también en aquellas cuyo fin es controlar la presión intraocular en pacientes que sufren de glaucoma. El objetivo principal de esta tesis se refiere a la aplicación de una serie de pruebas diagnósticas, de mínimamente a no-invasivas, sugeridas por el Tear Film & Ocular Society Dry Eye WorkShop II (TFOS DEWS II) que pueden ayudar a mejorar los resultandos refractivos y visuales en la cirugía oftálmica actual. La cirugía de cristalino, particularmente la cirugía moderna de catarata y la refractive lens exchange (RLE), centra la primera sección de la tesis. En realidad, el DED no está presente solo como complicación post-operatoria, sino que también es responsable de resultados refractivos y visuales no deseados dado que parte del examen pre-operatorio en la cirugía del cristalino puede verse influida por una película lagrimal deficiente (por ej. biometría ocular y topografía corneal). La literatura revisada ha demostrado poca información en el uso de técnicas avanzadas para evaluar la película lacrimal en pacientes que se someten a cirugía de cristalino, siendo estos hallazgos los más importantes para evitar resultados subóptimos después de la intervención. Posteriormente, en la cirugía refractiva corneal moderna, a pesar de la seguridad y efectividad en la corrección de errores refractivos tales como miopía, hipermetropía y astigmatismo, el DED post-quirúrgico sigue siendo un problema recurrente y unas de las complicaciones más referidas por los pacientes. Recientemente, nuevas técnicas (por ej. small incision lenticule extraction (SMILE)) han sido introducidas con el fin de reducir el desarrollo de DED. El uso de la microscopia confocal in-vivo, así como un programa automático de análisis, has sido incluidos para proporcionar resultados objetivos más rápido que puedan ser comparados con la cirugía de la córnea tradicional (e.g. laser-assisted in situ keratomileusis (LASIK)).El manejo de glaucoma mediante colirios oculares con preservantes puede llevar a deterioro de la superficie ocular con una larga proporción de pacientes con quejas del DED tanto como signos (como enrojecimiento ocular) tanto como síntomas (como incomodidad ocular, fotofobia, etc.). De los nuevos procedimientos oculares para controlar la presión intraocular reduciendo la necesidad del manejo tópico, la cirugía de glaucoma minimamente invasiva (MIGS) es prometedora también en mejorar la homeostasis de la superficie ocular. Sin embargo, muy poco ha sido investigado y la necesidad de una mejor comprensión ha llevado a administrar una serie de pruebas avanzadas para el diagnóstico de ojo DED con objeto de revelar los resultados a corto plazo sometidos a MIGS. Los estudios de investigación detallados en esta tesis evalúan una serie de técnicas avanzada de diagnóstico para comprender el papel de la DED en los procedimiento actuales de cirugía oftálmica con propósitos refractivos y visuales pero también para el manejo de enfermedades como el glaucoma. Asimismo, dichos estudios tratan de descubrir cual son las pruebas más importantes, mínimamente o no-invasivas, capaces de revelar el papel del DED en la cirugía oftálmica que llevarían a una mejora en los resultados tanto refractivos como visuales, así como los referidos por los pacientes.Dry eye disease (DED) can play an important role in ophthalmic procedures with refractive aims such as those involving the cornea (corneal laser surgery) or the crystalline lens (refractive lensectomy or cataract surgery) but also in the treatment of other conditions such as glaucoma. This thesis describes the application of a series of minimally to non-invasive diagnostic DED tests recommended by the recent Tear Film & Ocular Society Dry Eye WorkShop II (TFOS DEWS II) to help to improve the understanding of the impact of dry eye on the refractive and visual outcomes in the ophthalmic surgery and the impact of ophthalmic surgery on the ocular surface. Intraocular lens surgery, in particular modern cataract and refractive lens-exchange (RLE) surgery, is the focus of the first section of the thesis. In fact, DED is not only present as a post-operative complication but can also be responsible for sub-optimal refractive and visual outcomes since parts of the pre-operative examination pathway can be influenced by a depleted tear film (e.g. biometry and corneal topography). A literature review suggests little evidence of the routine use of advanced tear film assessments in patients undergoing intraocular lens surgery and there is little information on which DED findings are most important to avoid suboptimal clinical outcomes. Studies were carried out to explore the most relevant DED tests as recommended by the TFOS DEWS II. The key findings were validated questionnaires such as Ocular Surface Disease Index (OSDI) and Dry Eye Questionnaire 5-items (DEQ-5) and tear metrics such as non-invasive keratograph break-up time (NIKBUT), tear film volume (TMH) and tear osmolarity. In modern corneal refractive surgery, despite numerous publications and studies demonstrating the safety and efficacy in correcting refractive errors such as myopia, hyperopia and astigmatism, post-operative DED is still problematic and of the most common complications after surgery. Recently, newer techniques (e.g. small incision lenticule extraction (SMILE)) have been introduced with the aim of providing excellent visual outcomes whilst overcoming some of the limitations of more established procedures including undesirable alterations to corneal nerve structure and function and DED development. The use of in-vivo confocal microscopy was used to compare corneal nerve structure after SMILE with that seen after traditional laser-assisted in situ keratomileusis (LASIK). The results showed FS-LASIK surgery had more impact on DED symptomatology, TMH and NIKBUT and has led to significant change to the corneal nerve fibre metrics considered than SMILE surgery. Glaucoma management with topical preserved eyedrops can lead to deterioration of the ocular surface in a large proportion of patients with DED issues in terms of signs (e.g. ocular redness) and symptoms (grittiness, photophobia, etc.). Of the newer surgical procedures designed to control intraocular pressure reducing the need for topical management, minimally-invasive glaucoma surgery (MIGS) seems to be promising and could improve the homeostasis of the ocular surface in glaucoma patients. However, very little research on this topic has been published and an advanced pilot investigation to explore the use of a diagnostic battery of tests for DED after MIGS was carried out. Reduction in IOP was achieved by the procedure together with the reduction in DED symptomatology, increase of stability of the tear film and improvement of the ocular surface staining. In summary, the research studies detailed in this thesis use a series of advanced diagnostic techniques primarily to understand the role of DED in patients undergoing ophthalmic procedures for refractive and visual indications but also in patients being treated for glaucoma. They also explore which are the most important tests, in terms of identifying the impact of DED in ophthalmic surgery. Better diagnosis and management of DED in patients undergoing ophthalmic surgery will lead to optimal refractive, visual and patient-reported outcomes

Refractive and visual outcomes of femtosecond laser-assisted cataract surgery

Objective: To compare refractive and visual acuity outcomes of femtosecond laser-assisted cataract surgery (FLACS) to manual surgery. Participants: Consecutive series of patients in a private ophthalmic practice in Sydney, with 337 eyes undergoing FLACS on the LenSx platform and 230 eyes manual cataract surgery. Main Outcome Measures: Astigmatism, surgically-induced corneal astigmatism, achievement of target refraction and corrected and uncorrected distance visual acuity (UDVA). Results: The FLACS group had statistically less mean residual post-operative astigmatism by 0.18D (p<0.001) than the manual group. The femtosecond laser produced equivalent mean magnitude and variability of surgically-induced corneal astigmatism compared to manual cataract surgery. Both surgical methods had equivalent achievement of target spherical equivalent (69% within 0.5 D of target refraction, p=0.911). In eyes with good visual potential and an emmetropic target, post-operative UDVA was statistically better in the femtosecond group with an average improvement of 2.4 logMAR letters (p=0.020). Conclusions: Femtosecond cataract surgery produced less residual post-operative refractive astigmatism and better unaided distance visual acuity compared to manual cataract surgery. However there was no improvement in the achievement of target post-operative refraction

The role of dry eye disease in cataract and refractive surgery

Dry eye disease (DED) can play an important role in ophthalmic procedures with refractive aims such as those involving the cornea (corneal laser surgery) or the crystalline lens (refractive lensectomy or cataract surgery). This thesis describes the application of a series of minimally to non-invasive diagnostic DED tests recommended by the recent Tear Film & Ocular Society Dry Eye WorkShop II (TFOS DEWS II) to help to improve the understanding of the impact of dryeye on the refractive and visual outcomes in the ophthalmic surgery and the impact of ophthalmic surgery on the ocular surface.Intraocular lens surgery, in particular modern cataract and refractive lens-exchange (RLE) surgery, is the focus of the first section of the thesis. In fact, DED is not only present as a post-operative complication but can also be responsible for sub-optimal refractive and visual outcomes since parts of the pre-operative examination pathway can be influenced by a depleted tear film (e.g. biometry and corneal topography). A literature review suggests little evidence ofthe routine use of advanced tear film assessments in patients undergoing intraocular lens surgery and there is little information on which DED findings are most important to avoid suboptimal clinical outcomes. Studies were carried out to explore the most relevant DED tests as recommended by the TFOS DEWS II. The key findings were that pre-operative DED metrics such as reduced tear meniscus height (<0.20 mm) together with increased DED symptoms measured with Ocular Surface Disease Index (OSDI) (score ≥13) were potentially relevant to increase the chance of having less accurate refraction and poorer visual outcomes after lens surgery. Contrarily, Dry Eye Questionnaire 5-items (DEQ-5), that is a useful tool to evaluate ocular comfort, might be not designed to consider visual function that could potentially be affected by DED or cataract and might be not a good sensitive indicator of the refractive and visual outcomes after lens surgery.In modern corneal refractive surgery, despite numerous publications and studies demonstrating the safety and efficacy in correcting refractive errors such as myopia, hyperopia and astigmatism, post-operative DED is still problematic and of the most common complications after surgery. Recently, newer techniques (e.g. small incision lenticule extraction (SMILE)) have been introduced with the aim of providing excellent visual outcomes whilst overcoming some of the limitations of more established procedures including undesirable alterations to corneal nerve structure and function and DED development. The use of in-vivo confocal microscopy was used to compare corneal nerve structure after SMILE with that seen after traditional laser-assisted in situ keratomileusis (LASIK). The results showed FS-LASIK surgery had more impact on the corneal nerve fibre metrics (up to 75% of reduction) compared to SMILE surgery (up to 23%). Additionally, DED symptoms after FS-LASIK observed a significant two to four-fold increase (OSDI and DEQ-5) where also tear volume significantly decreased after surgery (from 0.32 ± 0.13 to 0.22 ± 0.09 mm).In summary, the research studies detailed in this thesis use a series of advanced diagnostic techniques primarily to understand the role of DED in patients undergoing ophthalmic procedures for refractive and visual indications. They also explore which are the most important tests, in terms of identifying the impact of DED in ophthalmic surgery. Better diagnosis and management of DED in patients undergoing ophthalmic surgery will lead to optimal refractive, visual and patient-reported outcomes

Refractive and visual outcomes of femtosecond laser-assisted cataract surgery

Objective: To compare refractive and visual acuity outcomes of femtosecond laser-assisted cataract surgery (FLACS) to manual surgery. Participants: Consecutive series of patients in a private ophthalmic practice in Sydney, with 337 eyes undergoing FLACS on the LenSx platform and 230 eyes manual cataract surgery. Main Outcome Measures: Astigmatism, surgically-induced corneal astigmatism, achievement of target refraction and corrected and uncorrected distance visual acuity (UDVA). Results: The FLACS group had statistically less mean residual post-operative astigmatism by 0.18D (p<0.001) than the manual group. The femtosecond laser produced equivalent mean magnitude and variability of surgically-induced corneal astigmatism compared to manual cataract surgery. Both surgical methods had equivalent achievement of target spherical equivalent (69% within 0.5 D of target refraction, p=0.911). In eyes with good visual potential and an emmetropic target, post-operative UDVA was statistically better in the femtosecond group with an average improvement of 2.4 logMAR letters (p=0.020). Conclusions: Femtosecond cataract surgery produced less residual post-operative refractive astigmatism and better unaided distance visual acuity compared to manual cataract surgery. However there was no improvement in the achievement of target post-operative refraction