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AIM:To evaluate corrective effect and stability of corneal morphology in patients with moderate to high myopia after 2a treatment of femtosecond laser assisted laser in situ keratomileusis(FS-LASIK)Xtra.METHODS:Retrospective case-control study. A total of 30 cases(58 eyes)Patients with moderate to high myopia combined with astigmatism who planned to undergo refractive surgery in our hospital from August 2019 to August 2020 were included, and different types of surgery were performed respectively based on the relevant index of keratoconus screening in the preoperative corneal topography. They were divided into FS-LASIK group and Xtra group, with 15 cases(29 eyes)in each group. Uncorrected visual acuity(UCVA), best corrected visual acuity(BCVA), spherical equivalent(SE)and the corneal curvature of the anterior and posterior surfaces of different diameters(3, 5 and 7 mm)measured by Sirius three-dimensional corneal topography were observed preoperatively and 3 mo, 1 and 2 a postoperatively.RESULTS: The UCVA of the two groups of patients at different time points after surgery was significantly increased compared with preoperatively(both P<0.01), and there was no difference in UCVA and SE between the two groups(P>0.05). After 2 a postoperatively, residual astigmatism was -0.25-0 D in 25 eyes(86%)of the FS-LASIK Xtra group and 24 eyes(83%)of the FS-LASIK group. The actual corrected SE and expected corrected SE of both groups were positively correlated(both P<0.05). There were differences in corneal curvature on the surface of different diameter areas(3, 5, and 7 mm)between the two groups at 3 mo, 1, and 2 a postoperatively compared with preoperatively. After 1 and 2 a postoperatively, the corneal posterior surface curvature of the FS-LASIK Xtra group with corneal diameter of 3 and 5 mm was higher than that of the FS-LASIK group(P<0.05).CONCLUSIONS:FS-LASIK Xtra has good safety, efficacy and predictability in correcting patients with moderate to high myopia.
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Background: LASIK for refractive error correction has become a universal surgery. Despite its popularity, the estimated prevalence of traumatic flap dislocations in post?LASIK patients is 3.9%, and it is sometimes associated with epithelial ingrowth. The prognosis in such cases depends on the rapid surgical revision of the flap with the removal of the EI and perioperative steps to prevent Epithelial ingrowth (EI) recurrence in the future. Purpose: The video aims to display the steps involved in revising the flap, removing EI, and tips to prevent its recurrence. Synopsis: A 33?year?old post? LASIK patient presented with decreased vision, photophobia, and glare during the COVID pandemic in the right eye for 2 months. The best?corrected visual acuity was reduced to 6/60. The anterior segment revealed traumatic flap dislocation along with macro fold temporally and epithelial ingrowth. She underwent a successful flap revision surgery with no recurrence of epithelial ingrowth postoperatively. Highlights: A successful revision of a 2?month? old traumatic folded flap was performed along with the complete removal of EI. It explains the step?by?step approach to avoid the recurrence of EI in each step of the surgical revision of the flap. The video is self?explanatory and guides novice surgeons too
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Background: In LASIK (laser in situ keratomileusis), a hinged corneal flap is made, which enables the flap to be lifted and the excimer laser to be applied to the stromal bed. If the hinge of the corneal flap detaches from the cornea, the flap is called a free cap. A free cap is a rare intra-operative complication of LASIK most commonly associated with the use of a microkeratome on corneas with flat keratometry, which predisposes to a small flap diameter. Free caps are preventable and treatable. Rarely does the complication lead to a severe or permanent decrease in visual acuity. Purpose: As free caps are avoidable, prevention is critical. Our video gives some tips and tricks on how to avoid a free flap and also focuses on how to manage a cut through a free flap. Synopsis: If a free cap is created, the surgeon must decide whether to continue with excimer laser ablation or to abort the procedure. When to abort: If the stromal bed is irregular, the flap is replaced without applying laser ablation. Without ablation, generally, there is no change in refractive error or significant loss of visual acuity. When to continue: If the stromal bed is regular and the cap is of normal thickness, the surgeon may proceed with ablation. To prevent desiccation, the free cap should be handled with caution and should be placed on a drop of balanced salt solution. The free cap should be placed epithelial facing up, along with a bandage contact lens. The endothelial cell pump mechanism typically allows the cap to re-adhere tightly. Highlights: Risk factors for a free cap are generally anatomic or mechanical. Especially in flat corneas, an appropriate ring and stop size should be chosen looking at the nomogram on the basis of the keratometry values. Deep orbits and deep-seated eyes should be looked for as PRK is a better option in such cases. Inadequate suction should be dealt with a lot of care, and once this is done, the vacuum should be stopped. Re-docking of the microkeratome with suction can be done again. Prior testing of the microkeratome and a good verbal anesthesia are a few more such important points to be pondered upon. This video gives us such tips and is a comprehensive video for a novice surgeon performing microkeratome LASIK
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Purpose: To compare the visual outcomes following topography?guided laser in situ keratomileusis (LASIK) treatment using manifest refraction versus a new topography analysis software. Methods: A prospective, randomized, observer?masked contralateral study was conducted in the refractive services of a tertiary eye care hospital in South India. Analysis of visual outcomes, corneal higher?order aberrations, and contrast sensitivity were performed at 3 months postoperative visit following uneventful topography?guided LASIK using the Wavelight EX500. One eye was treated with the Contoura platform using manifest refraction (Contoura), while the contralateral eye was treated using an ablation profile planned by the Phorcides Analytic Engine (Phorcides). Results: Sixty eyes of 30 patients were included in the study. At 3 months postoperative visit, the uncorrected distance visual acuity (UDVA) in the Contoura and Phorcides groups was logarithm of the minimal angle of resolution (logMAR) 0.04 ± 0.07 and logMAR 0.06 ± 0.1, respectively (P = 0.483). Postoperative manifest refractive spherical error (MRSE) was 0.12 ± 0.22 and ? 0.06 ± 0.20 D in the Contoura and Phorcides groups, respectively (P = 0.338). Although higher number of eyes demonstrated a gain in one or more lines of corrected distance visual acuity (CDVA) in the Contoura group (16.6% vs. 6.6%), the difference was not statistically significant (P = 0.361). Vector analysis (Alpins criteria) for postoperative cylinder, contrast sensitivity measurement, and corneal higher?order aberration profile showed no significant difference between the two groups at 3 months postoperative visit (P = 0.213, 0.514, and 0.332, respectively). Conclusion: Quantitative and qualitative visual outcomes with the Phorcides Analytic Software were similar to the Contoura treatment using manifest refraction.
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Purpose: To evaluate the outcomes of transepithelial corneal collagen crosslinking (CXL) for management of corneal ectasia after laser?assisted in situ keratomileusis (LASIK). Methods: CXL was performed on 18 eyes of 16 patients either with LASIK flap lift (n = 9; 365 nm, 30 mW/cm2, 4 minutes, pulse) or with transepithelial flap?on (n = 9 eyes; 365 nm, 3 mW/cm2, 30 minutes) technique. Postoperative change in maximum keratometry (Kmax), anterior elevation, posterior elevation, spherical equivalent (SE), logMAR uncorrected distance visual acuity (UDVA), aberrations, and central corneal thickness (CCT) were evaluated at 12 months postoperatively. Results: A total of 18 eyes of 16 patients (11 males, 5 females) were included. Overall, Kmax flattened more after flap?on CXL (P = 0.014) compared to flap?lift CXL. The endothelial cell density and posterior elevation were stable throughout the follow?up period. Index of vertical asymmetry (IVA), keratoconus index (KI), and central keratoconus index (CKI) decreased after flap?on CXL at 12 months, postoperatively (P < 0.05), whereas there were no statistically significant changes in these parameters after flap?off CXL group. The spherical aberrations and total root mean square decreased after flap?lift CXL at 12 months, postoperatively (P < 0.05). Conclusion: In our study, transepithelial collagen crosslinking was successfully used to halt disease progression in post?LASIK keratectasia. We recommend flap?on surgical technique for these cases
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Purpose: This work assesses the change in tear function after LASIK surgery. Methods: This prospective, observational study was conducted in the Refractive Clinic of a tertiary care rural hospital. Tear dysfunction symptoms and the tear function tests were assessed in 269 eyes of 134 patients, OSDI score was used to document the tear dysfunction symptoms. Tear function was assessed by tear meniscus height, tear film break?up time (TBUT), Lissamine green staining, corneal fluorescein staining, Schirmer test 1 without anesthesia before and at 4–6 weeks and 10–12 weeks after LASIK surgery. Results: Preoperatively OSDI score was 8.54 ± 7.71. It increased to 15.11 ± 9.18 postoperatively at 4–6 weeks after LASIK surgery and 13 ± 9.56 at 10–12 weeks after LASIK surgery Mean TBUT preoperatively was 7.82 ± 3.57 sec which decreased to 5.34 ± 2.56 sec at 4–6 weeks and to 4.53 ± 2.63 sec at 10–12 weeks postoperatively. The number of eyes with clear secretion decreased from 40.5% preoperatively to 23.4% at 4–6 weeks and to 22.3% at 10–12 weeks postoperatively, whereas the granular and cloudy secretions increased significantly in eyes after LASIK surgery. The prevalence of eyes with Lissamine green score >3 (dry eye) increased from 17.1% preoperatively to 27.9% at 4–6 weeks and to 30.5% at 10–12 weeks. Similarly, the number of eyes showing positive fluorescein corneal staining increased from 5.6% preoperatively to 19% postoperatively at 4–6 weeks. Mean Schirmer score was 28.83 ± 6.39 mm preoperatively, 22.47 ± 5.38 mm at 4–6 weeks, and 21.27 ± 4.99 mm at 10–12 weeks after LASIK surgery. Conclusion: The prevalence of dry eye increased after LASIK as was assessed by an increase in the tear dysfunction symptoms using OSDI score and the deranged values of various tear function tests after LASIK surgery
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Purpose: To compare the clinical outcomes of diffractive multifocal and monofocal lenses in post?laser in situ keratomileusis (LASIK) patients who underwent cataract surgery. Methods: This was a retrospective, comparative study of clinical outcomes that was conducted at a referral medical center. Post?LASIK patients who underwent uncomplicated cataract surgery and received either diffractive multifocal or monofocal lens were studied. Visual acuities were compared at baseline and postoperatively. The intraocular lens (IOL) power was calculated with Barrett True?K Formula only. Results: At baseline, both groups had comparable age, gender, and an equal distribution hyperopic and myopic LASIK. A significantly higher percentage of patients receiving diffractive lenses achieved uncorrected distance visual acuity (UCDVA) of 20/25 or better (80 of 93 eyes, 86% vs. 36 of 82 eyes, 43.9%, P = 1.0 x 105) and uncorrected near vision of J1 or better (63% vs. 0) compared to the monofocal group. The residual refractive error had no significant difference (0.37 ± 0.39 vs. 0.44 ± 0.39, respectively, P = 0.16) in these two groups. However, more eyes in the diffractive group achieved UCDVA of 20/25 or better with residual refractive error of 0.25–0.5 D (36 of 42 eyes, 86% vs. 15 of 24 eyes, 63%, P = 0.032) or 0.75–1.5 D (15 of 21 eyes, 23% vs. 0 of 22 eyes, P = 1.0 x 10?5) compared to the monofocal group. Conclusion: This pilot study shows that patients with a history of LASIK who undergo cataract surgery with a diffractive multifocal lens are not inferior to those who receive monofocal lens. Post?LASIK patients with diffractive lens are more likely to achieve not only excellent near vision, but also potentially better UCDVA, regardless of the residual refractive error.
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Purpose: To determine the safety and efficacy of low?energy settings in small incision lenticule extraction (SMILE) for correcting myopia and myopic astigmatism. Methods: We included patients aged ?18 years with the myopia of ?0.5 to ?10 D and myopic astigmatism of ?0.5 to ?5 Dcyl in this retrospective case series performed at a private eye hospital in South India. All patients had preoperative best?corrected visual acuity of LogMar 0.0 ± 0, with stable refraction for 1 year and normal corneal topography. Ocular surface disease and other pathology cases were excluded. The repetition rate of the laser was 500 kHz, and the pulse energy was 110 nJ. The lenticule diameter was set at 6.5 mm, cap diameter was 7.20 mm, and intended cap thickness was 110–130 ?. The spot distance was 4.5 ?m. All patients were evaluated immediately postoperation and on postoperative days 1, 8, and 30. Results: Overall, 541 eyes were included. The mean patient age was 25.03 ± 4.1 years. The mean spherical error was ?3.76 ± 1.84 Ds. The mean cylinder was ?1.24 ± 0.91. The mean spherical equivalent of refraction was ?4.22 ±1.94 D. The logMAR on postoperative day 1 was 0.0 ± 0. The mean spherical equivalent at 1 month was 0.28 ± 1.06 D. There was no loss of Snellen’s lines after the procedure. The mean spherical equivalent of refraction to the target was 95% within ± 0.50 D. The postoperative astigmatism was within 0.5 Dycl. No intraoperative complications of SMILE including retained lenticule fragments, tears of incision, or improper dissection occurred. Conclusion: Low?energy settings in SMILE are safe and effective in correcting myopia and myopic astigmatism including high cylinders (>3 Dcyl).
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Purpose: To develop a nomogram in cases with mismatch between subjective and Topolyzer cylinder, and based on the magnitude of the mismatch, customize a treatment plan to attain good visual outcomes post?laser?assisted in situ keratomileusis (LASIK) surgery. Methods: The patients were evaluated preoperatively using corneal tomography with Pentacam. Five optimal corneal topography scans were obtained from the Topolyzer Vario were used for planning the LASIK treatment. For the nomogram purpose, the patients were divided into three categories based on the difference between the subjective cylinder and Topolyzer (corneal) cylinder. The first group (group 1) consisted of eyes of patients, where the difference was less than or equal to 0.4 D. The second group (group 2) consisted of eyes, where the difference was more than 0.4 D and the subjective cylinder was lesser than the Topolyzer cylinder. The third group (group 3) included eyes where the difference was more than 0.4 D but the subjective cylinder was greater than the Topolyzer cylinder. LASIK was performed with the WaveLight FS 200 femtosecond laser and WaveLight EX500 excimer laser. Assessment of astigmatism correction for the three groups was done using Aplins vector analysis. For comparison of proportions, Chi?square test was used. A P value less than 0.05 was considered statistically significant. Results: The UDVA was statistically significantly different when compared between groups 1 and 2 (P = 0.02). However, the corrected distance visual acuity (CDVA) was similar among all the three groups (P = 0.1). Group 3 showed an increase of residual cylinder by ?0.25 D, which was significant at intermediate and near reading distances (P < 0.05). Group 3 showed significantly higher target?induced astigmatism (TIA) compared to groups 1 and 2 (P = 0.01). The mean surgically induced astigmatism (SIA) was the least in group 2, which was statistically significant (P < 0.01). Conclusion: The outcomes for distance vision using our nomogram postoperatively were excellent, but further refinement for improving the near vision outcomes is required
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La violeta de genciana es un colorante orgánico sintético, descrito por primera vez por Charles Lauth en 1861. Tiene propiedades antibacterianas, antifúngicas, antihelmínticas, antitripanosómicas, antiantiogénicas y antitumorales. Tiene diversos mecanismos de acción, entre los que principalmente se encuentra bloquear la actividad de las nicotinamida adenina dinucleótido fosfato oxidasas, evitando la generación de radicales superoxidativos y la posterior inflamación. En los últimos años se ha utilizado en marcadores para procedimientos en diferentes especialidades médicas, incluidos los de oftalmología. La tinta de violeta de genciana se describe por el fabricante como no tóxica, sin embargo existe evidencia clínica y experimental que sugiere que puede ser tóxica para el endotelio corneal y puede llegar a generar queratitis lamelar difusa posterior a LASIK y Femto-LASIK. Se describe el caso de una paciente de 23 años de edad, que presentó diversas patologías en la córnea después del uso de marcador quirúrgico durante procedimiento refractivo Femto-LASIK.
Gentian violet is a synthetic and organic dye. First described by Charles Lauth in 1861. It has antibacterial, antifungal, anthelmintic, antitrypanosomal, antiangiogenic, and antitumoral properties. It has various mechanisms of action, among which is mainly blocking the activity of nicotinamide adenine dinucleotide phosphate oxidases, preventing the generation of superoxidative radicals and subsequent inflammation. In recent years, it has been used as markers for procedures in different medical specialties, including ophthalmology. Gentian violet ink is described by the manufacturer as non-toxic, however, there is clinical and experimental evidence suggesting that it may be toxic to the corneal endothelium and may cause diffuse lamellar keratitis after LASIK and Femto-LASIK. The case about a 23-year-old female patient who presented various pathologies in the cornea after the use of a surgical marker during the Femto-LASIK refractive procedure is described.
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Humans , Female , AdultABSTRACT
AIM: To compare the changes in corneal densitometry after small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(FS-LASIK)and investigate the effect of corneal interface haze on vision after SMILE.METHODS: Prospective cohort study. A total of 93 patients(186 eyes)who were scheduled to undergo refractive surgery at the Ophthalmic Refractive Surgery Center of the Affiliated Hospital of Nantong University from May 2020 to October 2021 were included in the study, and there were 48 patients(96 eyes)in the SMILE group and 45 patients(90 eyes)in the FS-LASIK group. The changes in corneal densitometry, spherical equivalent(SE), and uncorrected visual acuity(UCVA)were observed and compared between the two groups before and at 1d, 1wk, 1, 3 and 6mo after surgery.RESULTS: The 93 patients all successfully completed the surgery, and there were no related complications during and after the surgery, and there were no lost cases. The UCVA of FS-LASIK group was 0.044±0.064 and -0.001±0.065 respectively at 1d and 1wk after surgery, which was better than that of SMILE group(0.102±0.077 and 0.023±0.064; all P<0.05). There was no statistical difference in the SE between the two groups at the postoperative follow-ups(P>0.05). The corneal densitometry values at 0-2 and 2-6 mm from corneal vertex and total corneal densitometry at 1d postoperatively in the FS-LASIK group were 18.0(17.5, 18.6), 16.2(15.6, 16.7)and 16.7(16.1, 17.3), which were lower than those of SMILE group [18.6(18.1, 19.3), 16.8(16.4, 17.4), 17.2(16.6, 17.8)](all P<0.05); The corneal densitometry values at 0-2 and 2-6 mm from corneal vertex and total corneal densitometry at 1wk postoperatively in the FS-LASIK group were 17.2(16.7, 17.6), 15.5(15.0, 15.9)and 15.9(15.3, 16.7), which were lower than those of SMILE group [17.6(17.1, 18.3), 16.0(15.6, 16.5), 16.6(15.9, 17.1)](all P<0.05).CONCLUSIONS: The transient interface haze after SMILE is responsible for the early higher corneal densitometry than FS-LASIK. The presence of interface haze is probably a factor for the quality of vision.
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AIM: To observe and compare the changes in retinal peripheral refraction and aberrations after femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)versus small incision lenticule extraction(SMILE)for myopia correction.METHODS: A total of 71 patients(71 eyes)with myopia who underwent FS-LASIK from October 2022 to April 2023 in our hospital were selected as the FS-LASIK group, and 80 patients(80 eyes)with myopia who underwent SMILE were selected as the SMILE group. All patients underwent corneal wavefront aberration measurement and multispectral refractive topography preoperatively and 3mo postoperatively, as well as refraction difference value(RDV)in the range of 0°～10°, 10°～20°, 20°～30°, 30°～40°, and 40°～53° in the annulus of the retina, which were recorded as RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), and RDV-(40°～53°). The results of two groups of patients were compared.RESULTS: No significant differences were observed in RDV-(0°～10°), RDV-(10°～20°), RDV-(20°～30°), RDV-(30°～40°), RDV-(40°～53°)between the two groups at 3mo post-operation(all P>0.05). Furthermore, the RDV-(20°～30°), RDV-(30°～40°)and RDV-(40°～53°)of the two groups at 3mo postoperatively were all significantly lower than those preoperatively(all P<0.05). The changes in coma(horizontal)and spherical aberration(SA)at 3mo postoperatively were smaller in the SMILE group [0.106(0.056, 0.171)and 0.115(0.081, 0.182)μm] than in the FS-LASIK group [0.206(0.104, 0.355)and 0.197(0.128, 0.254)μm](Z=-4.170, -5.016, all P<0.05). A negative correlation was found between postoperative SA and postoperative RDV-(10°～53°)(rs=-0.205, -0.181, -0.226, -0.244, all P<0.05).CONCLUSION: Both FS-LASIK and SMILE reduced retinal hyperopic defocus in the peripapillary macular range of 20°～53° eccentricity, and the postoperative changes in coma(horizontal)and SA were smaller with SMILE than with FS-LASIK. There was a certain correlation between postoperative SA and postoperative retinal peripheral defocus.
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Femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)and small incision lenticule extraction(SMILE)are the mainstream corneal refractive surgeries at present. Despite efficacy, safety and predictability they have showed in refractive error correction, there are still complications relating to femtosecond laser, such as suction loss and opaque bubble layer(OBL), due to that the production of corneal flap or lenticule is dependent on the femtosecond laser. OBL is a complication that is unique to femtosecond laser surgery and the bubbles are generated from photo-disruptive effect towards corneal tissues which consisted of water vapor and carbon dioxide, and OBL gradually formed when the bubbles are trapped in the stroma. The bubbles can influence the intraoperative manipulation and postoperative visual quality. This review discusses the mechanism, grading, classification, and influencing factors of OBL and its effects on intraoperative manipulations and postoperative recovery, in the hope of providing reference and basis for further clinical studies.
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AIM:To evaluate the changes in corneal biomechanics of patients with moderate refractive error after receiving small-incision lenticule extraction(SMILE)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)using the corneal visualization Scheimpflug technology(Corvis ST).METHODS:Prospective cohort study. A total of 65 moderate myopia patients(65 eyes)who were scheduled to undergo refractive surgery at the Ophthalmic Refractive Surgery Center of the Ningxia Eye Hospital from November 2020 to November 2021 were included in the study, and there were 30 eyes in the SMILE group and 35 eyes in the FS-LASIK group. The changes in corneal biomechanical parameters, including integrated radius(IR), inverse concave radius(ICR), deformation amplitude ratio 2mm(DAR2), stiffness parameter at first applanation(SP-A1), ambrosio relational thickness(ARTh)and the central curvature radius at highest concavity(HC-Radius)were observed by Corvis ST between both groups preoperatively and 1 and 3mo postoperatively.RESULTS: There were no statistical significance in biomechanical parameters between two groups of patients 1 and 3mo postoperatively(P&#x003E;0.05). IR, ICR and DAR2 of each groups of patients 1 and 3mo postoperatively were significantly increased than those preoperatively, and SP-A1, ARTh and HC-Radius were significantly decreased than those preoperatively(all P&#x003C;0.05). The biomechanical parameters at 1mo and 3mo postoperatively showed no statistical significance(P&#x003E;0.05). In addition, a positive correlation was found between central corneal thickness(CCT)and ARTh and SP-A1 of the two groups of patients at 3mo postoperatively(FS-LASIK group: r=0.727, 0.819, SMLIE group: r=0.683, 0.434, all P&#x003C;0.05), while a negative correlation was found between CCT and IR and ICR at 3mo postoperatively.(FS-LASIK group: r=-0.697, -0.622, SMLIE group: r=-0.447, -0.491, all P&#x003C;0.05).CONCLUSION:For patients with moderate myopia, both SMILE and FS-LASIK can reduce corneal biomechanical stability. Both surgeries showed no significant differences in the effect on biomechanical, and the biomechanical has been stabilized at 1mo postoperatively. A correlation was found between postoperative CCT and ARTh, SP-A1, IR and ICR.
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AIM: To study the patient characteristics and keratorefractive surgery(KRS)practice in central India.METHOD: The retrospective study was conducted on 410 patients who underwent KRS from June 2017 to April 2022 at a tertiary eye care center in central India. Demographic data of the patients presenting for the spectacle free vision like age, sex, residence in the form of urban or rural area, refractive error, cause for spectacle-free vision, best-corrected visual acuity, types of procedure, postoperative follow-up and complications were recorded.RESULTS: Among the 410 patients who presented for spectacle-free vision, 324 patients were considered for KRS(79.0%), and 200 patients(61.7%)underwent the laser-assisted in situ keratomileusis(LASIK)procedure, whereas 124 patients(38.3%)underwent the photorefractive keratectomy(PRK)procedure. The final study group comprised 179 female and 145 male. The mean age of the patients was(25±3.5)years. A majority of patients were from urban areas(n=250, 77.2%). The mean preoperative manifest refraction in the right and left eyes was -4.5±2.1 and -4.9±2.0, respectively. The mean surgical time in the LASIK patient was(15±2)min and(17±3)min for both eyes in PRK. None of the patients exhibited epithelial ingrowth, flap healing complications, or infection, and none of them required enhancement. Suboptimal corneal thickness(n=28, 32.6%)was the most common reason for rejection. At the end of the 1-year follow up, 3 patients who underwent the LASIK procedure exhibited regression(-0.5 D±1 D), with a refractive error correction of -6.75 D, -8.5 D, and -7.0 D, respectively.CONCLUSION: LASIK is the predominant procedure for the correction of refractive error in the central Indian population. Although the number of PRK procedures was small, both LASIK and PRK exhibited excellent visual outcome. Myopic regression should be considered when choosing LASIK for high myopia.
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Objective:To investigate the risk factors of high intraocular pressure (IOP) after femtosecond laser in situ keratomileusis (FS-LASIK) in patients with high myopia, and construct and verify nomogram model.Methods:A retrospective clinical study. From January 2019 to January 2021, 327 patients (654 eyes) with high myopia treated with FS-LASIK in the Department of Ophthalmology of the 910th Hospital of the People's Liberation Army Coalition Security Force were included in the study. The patients were categorized into high IOP group and non-high IOP group according to whether high IOP occurred after surgery, which were 60 cases and 120 eyes (18.35%, 60/327) and 267 cases and 534 eyes (81.65%, 267/327), respectively. The clinical data of patients in the two groups were analyzed and observed, and the indicators with differences were subjected to one-way and multifactorial logistic regression analyses, and the results of the regression analyses were visualized to obtain the column line graphs using R3.5.3 software, and the accuracy of the column line graphs was verified by the consistency index (C-index), the calibration curves, and the subject's work characteristic curves (ROC curves).Results:Comparison of the number of cases of affected corneal thickness ( χ2=7.424), corneal curvature ( χ2=9.849), glucocorticoid treatment ( χ2=7.222), intraoperative IOP fluctuation ( χ2=11.475), corneal hysteresis ( χ2=6.368), and the incidence of intraoperative complications ( χ2=6.673) in the hypertensive IOP group and the nonvisualized IOP group were statistically significant ( P<0.05). Binary logistic regression analysis showed that corneal thickness >450 μm, corneal curvature≤38 D, glucocorticoid treatment, intraoperative IOP fluctuation, corneal hysteresis ≤8.0 mm Hg (1 mm Hg=0.133 kPa), and intraoperative complications were the risk factors for the occurrence of high IOP after FS-LASIK surgery in patients with high myopia ( P<0.05). The C-index of the column-line graph prediction model based on this was 0.722 (95% confidence interval 0.684-0.760), the calibration curve and the ideal curve were basically the same, and the area under the ROC curve was 0.709. Conclusions:Corneal thickness> 450 μm, keratometric curvature ≤38 D, glucocorticoid treatment, intraoperative fluctuation of intraocular pressure, and corneal hysteresis ≤8.0 mm Hg are the risk factors for the development of hyperopic IOP in highly risk factors for the development of high IOP after FS-LASIK surgery in myopic patients. The column-line diagram model constructed on the basis of the risk factors hava good accuracy.
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Purpose: To assess the role of remote teleconsultation (TC) follow?up care following a successful and uneventful laser vision correction. Methods: The study is a retrospective, comparative analysis of patients undergoing laser vision correction at tertiary care eye hospital in Southern India. The patients were divided into two groups. The first group included patients operated on before the coronavirus disease (COVID?19) pandemic and were followed up with physical consultations during their follow?up visit (Group 1). The second group comprised patients operated on during the pandemic and had at least one remote TC during their post?operative follow?up (Group 2). Results: A total of 1088 eyes of 564 patients and 717 eyes of 372 patients were included in Group 1 and 2, respectively. The mean number of visits for the patients from Group 2 during the COVID period (2.56 +/? 0.74 days) was significantly lesser (P < 0.0001) than that of Group 1 in the pre?COVID period (3.53 +/? 1.07 days). Close to 90% of the eyes achieved an uncorrected distance visual acuity (UDVA) of 20/20 in both groups (P = 0.925). 96.50% of the eyes in Group 1 and 98.18% of the eyes in Group 2 achieved UCVA 20/25 or better (P = 0.049). Eight eyes (0.73%) in Group 1 and one eye (0.14%) in Group 2 reported a loss of 2 or more lines. However, the results were not statistically significant (P = 0.156). None of the groups had any patients who had a sight?threatening complication. Conclusion: Remote TC following refractive surgery is safe and can be effectively integrated into routine refractive practice to reduce travel to the hospital for a physical consult
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Aims: The aim of this study is to compare corneal parameters in: central corneal thickness (CCT), thinnest corneal thickness (TCT), mean radius of curvature (Rm) and anterior chamber depth (ACD) obtained from Pentacam Schiempflug and OCT Tomography imaging which are checked preoperatively and six months postoperatively after LASIK surgery.Methodology: Our sample consisted of 40 eyes. Changes in corneal dimensions were monitored before and after LASIK surgery using scheimpflug tomography (Pentacam HR) and optical coherence tomography (OCT). The parameters measured were CCT, TCT, Rm and the ACD. The results between the two techniques were compared with the Bland-Altman method.Results: During the analysis of the results, a statistically significant difference was observed between the two techniques in terms of the preoperative CCT as well as the TCT both preoperatively and postoperatively.Scheimpflug tomography gives higher values of the CCT than OCT, up to thickness 530nm, while above this it seems that OCT overestimates the thickness of the cornea. Scheimpflug tomography at the TCT seems to give higher values than OCT tomography, up to thickness 520 nm, while above that it seems that OCT tomography overestimates TCT. We have similar results postoperatively for TCT.The two techniques agree on the ACD and the Rm rating.Conclusion: How converging or different the two imaging devices are because it is important for both clinical practice and research may be a point of reference for starting a new research.
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Background: Topography guided laser-assisted in situ keratomileusis (LASIK) has always been some sort of an enigma in terms of its understanding and interpretation. Contoura LASIK is one such form of FDA approved topography guided LASIK on the Wavelight platform for virgin eyes. Inspite of promising so much, its complete application has not yet been fully understood and cannot be applied for all cases. Purpose: The iSMART Contoura LASIK is a software designed by the author, aimed to specifically to plan and treat eyes with Contoura LASIK. Synopsis: This is computer based software which studies the higher order aberrations being treated by the machine, and applies geometry and vector mathematics to appropriately modify the final treatment refraction so as to completely correct the refractive error. The software guides almost everything related to LASIK planning including safety parameters like percent tissue altered and residual stromal bed, the ring and stop size for microkeratome needed, femto flap diamter and Contoura planning. This software will be a useful tool for all Wavelight EX500 Contoura LASIK users. Highlights: This video demonstrates briefly the overview, working and utility of the iSMART LASIK software along with a quick understanding of how Contoura LASIK planning is done using it.
ABSTRACT
Purpose: To evaluate the visual outcomes of patients who underwent small?incision lenticule extraction (SMILE) for the treatment of myopic astigmatism with high cylinders (>2.5 diopters, D). Methods: Forty?two eyes of myopic astigmatism with a spherical error of magnitude between ? 0.5 and ? 6.0 Ds, cylindrical error of ? 2.5 to ? 4.5 Dcyl were included in the retrospective study. All patients were tested preoperatively and on days 1, 10, and 30 for uncorrected distance visual acuity, manifest refraction, and corrected distance visual acuity. Additional preoperative assessments were done including measurement of corneal thickness, corneal topography, and examination for ocular surface disease. All procedures were performed by a single experienced surgeon. VisuMax laser system (Carl Zeiss Meditec AG, Jena, Germany) was utilized for all the corrective refractive procedures. Results: Forty?two eyes were included. The logarithm of the minimum angle of resolution Uncorrected distance visual acuity (UDVA) was 1 ± 0.25 preoperatively and 0.00 ± 0.00 on postoperative day 30. There was no loss of corrected distance visual acuity (CDVA) lines. Conclusion: SMILE is a successful procedure in the treatment of both myopic spherical and cylindrical refractive errors including high cylindrical errors >?3 to ? 4.5 Dcyl.