PURPOSE: To compare the accuracy of intraocular lens (IOL) power calculation using conventional regression formulae or the American Society of Cataract and Refractive Surgery (ASCRS) IOL power calculator for previous corneal refractive surgery. METHODS: We retrospectively reviewed 96 eyes from 68 patients that had undergone cataract surgery after keratorefractive surgeries. We calculated the formula with two approaches: IOL powers using the ASCRS IOL power calculator and IOL powers using conventional formulae with previous refractive data (Camellin, Jarade, Savini, and clinical history method) or without prior data (0, 2 and, 4 mm total mean power in topography, Wang-Koch-Maloney, Shammas, Seitz, and Maloney). Two conventional IOL formulae (the SRK/T and the Hoffer Q) were calculated with the single K and double K methods. Mean arithmetic refractive error and mean absolute error were calculated at the first postoperative month. RESULTS: In conventional formulae, the Jarade method or the Seitz method, applied in the Hoffer Q formula with the single K or double K method, have the lowest prediction errors. The least prediction error was found in the Shammas-PL method in the ASCRS group. There was no statistically significant difference between the 10 lowest mean absolute error conventional methods, the Shammas-PL method and the Barrett True-K method calculated with using the ASCRS calculator, without using preoperative data. CONCLUSIONS: The Shammas-PL formula and the Barrett True-K formula, calculated with the ASCRS calculator, without using history, were methods comparable to the 10 most accurate conventional formulae. Other methods using the ASCRS calculator show a myopic tendency.
Cataract ; Humans ; Lenses, Intraocular* ; Methods ; Refractive Errors ; Refractive Surgical Procedures* ; Retrospective Studies

PURPOSE: To evaluate and compare published methods of calculating intraocular lens (IOL) power following myopic laser refractive surgery. METHODS: We performed a retrospective review of the medical records of 69 patients (69 eyes) who had undergone myopic laser refractive surgery previously and subsequently underwent cataract surgery at Samsung Medical Center in Seoul, South Korea from January 2010 to June 2016. None of the patients had pre-refractive surgery biometric data available. The Haigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug total corneal refractive power (TCRP) 3 and 4 mm (SRK-T and Haigis), Scheimpflug true net power, and Scheimpflug true refractive power (TRP) 3 mm, 4 mm, and 5 mm (SRK-T and Haigis) methods were employed. IOL power required for target refraction was back-calculated using stable post-cataract surgery manifest refraction, and implanted IOL power and formula accuracy were subsequently compared among calculation methods. RESULTS: Haigis-L, Shammas, Barrett True-K (no history), Wang-Koch-Maloney, Scheimpflug TCRP 4 mm (Haigis), Scheimpflug true net power 4 mm (Haigis), and Scheimpflug TRP 4 mm (Haigis) formulae showed high predictability, with mean arithmetic prediction errors and standard deviations of −0.25 ± 0.59, −0.05 ± 1.19, 0.00 ± 0.88, −0.26 ± 1.17, 0.00 ± 1.09, −0.71 ± 1.20, and 0.03 ± 1.25 diopters, respectively. CONCLUSIONS: Visual outcomes within 1.0 diopter of target refraction were achieved in 85% of eyes using the calculation methods listed above. Haigis-L, Barrett True-K (no history), and Scheimpflug TCRP 4 mm (Haigis) and TRP 4 mm (Haigis) methods showed comparably low prediction errors, despite the absence of historical patient information.
Cataract ; Humans ; Korea ; Lenses, Intraocular* ; Medical Records ; Methods* ; Refractive Surgical Procedures* ; Retrospective Studies ; Seoul

PURPOSE: To describe current cataract surgery practice patterns and changing trends among Korean ophthalmologists. METHODS: A survey of members of the Korean Society of Cataract and Refractive Surgery was performed in July 2018. One hundred and two (12.7%) of 801 questionnaires were returned for analysis. The data were analyzed using descriptive statistics and compared with previous surveys. RESULTS: Most of the respondents (75%) had been in practice for 6 or more years and performed an average of 31 cataract surgeries per month. The preferred method for cataract surgery was phacoemulsification (95%); 5% used a femtosecond laser. The use of topical anesthesia markedly increased from 69% (2012) to 80% (2018). The use of optical biometry exceeded that of ultrasound A-scan biometry. A multifocal intraocular lens was used by 76% of the respondents compared with 44% of the respondents in 2012. Topical nonsteroidal anti-inflammatory drugs were used by 70% of the respondents postoperatively. Most (59%) of these anti-inflammatory drugs were prescribed for 4 weeks. CONCLUSIONS: This survey provided a comprehensive update of the present cataract surgery practices in the Republic of Korea. The results emphasized the increasing use of premium intraocular lenses, optical biometry, and topical anesthesia.
Anesthesia ; Biometry ; Cataract ; Lenses, Intraocular ; Methods ; Phacoemulsification ; Refractive Surgical Procedures ; Republic of Korea ; Surveys and Questionnaires ; Ultrasonography

The excimer laser diopter correction has proven to be efficient and safe. This paper presents the principle of excimer laser refractive surgery. Based on analyzing the mathematics model of the human eye cornea, the authors have proposed a new model which can be used to proceed the myopia, hyperopia, astigmatism diopter correction. Also studied were the excimer laser's ablation mechanism and the flying-spot scanning technology. The research results have been directly applied to Ophthalmic excimer laser system. The correction of diopter is well improved.
Algorithms ; Cornea ; anatomy & histology ; Humans ; Keratomileusis, Laser In Situ ; methods ; Lasers, Excimer ; Models, Theoretical ; Photorefractive Keratectomy ; methods ; Refractive Surgical Procedures

PURPOSE: To compare the accuracy of central true net corneal power (cTNP) and mean true net corneal power (mTNP) of the Pentacam system to give a keratometry (K) reading for calculating IOL (intraocular lens) power in eyes following refractive surgery. METHODS: Refraction, an automated K-reading (Km), cTNP and mTNP were measured for 15 eyes that required cataract surgery and had previously undergone refractive surgery. The difference between postoperative manifest refraction values and target refraction values calculated with the SRK/T formula using cTNP were compared with the one using mTNP. RESULTS: The mean deviation from the desired post-cataract refractive outcome was 0.60 diopter (D) +/-0.47 (standard deviation) using cTNP; 0.75+/-0.54 using mTNP (p=0.386). The actual refraction was within +/-0.50D of the intended refraction for 60% (cTNP) and 33.3% (mTNP) of eyes, and within +/-1.00D for 93% (cTNP) and 66.7% (mTNP) of eyes. CONCLUSIONS: Although not statistically significant, the cTNP showed better accuracy than mTNP to give a keratometry (K) reading for post-refractive surgery eyes requiring cataract surgery.
Adult ; Cornea/*pathology/physiopathology/surgery ; Corneal Topography/*methods ; Female ; Humans ; *Lenses, Intraocular ; Male ; Middle Aged ; Myopia/*surgery ; Prosthesis Design ; *Refraction, Ocular ; *Refractive Surgical Procedures

PURPOSE: To compare the effects of performing a single limbal relaxing incision (LRI) combined with a clear corneal incision on a corneal astigmatism with that of paired LRIs in cataract surgery. METHODS: Medical records for 25 eyes in 20 patients who had undergone LRIs during cataract operations for with-the-rule astigmatism of 1.5 diopters (D) or more in topography were retrospectively reviewed. Single or paired LRIs were assigned randomly and were performed on the steepest axis; the degrees of arc were determined using the modified Gills nomogram. A clear corneal wound was made on the steepest vertical axis. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, and corneal astigmatism on topography were evaluated preoperatively and one month postoperatively. Naeser's polar value analysis was used to assess the efficacy of the LRIs. RESULTS: The mean depth of the LRIs and degrees of arc were 620+/-31 micrometer (87.1% of corneal thickness) and 56.84+/-19.68degrees, respectively. The mean postoperative UCVA and BCVA (log MAR) were significantly improved (0.51+/-0.37 and 0.09+/-0.12, respectively) (p<0.05). Average refractive and corneal astigmatisms were significantly reduced by 49.4 percent and 32.4 percent, respectively (p<0.05). The single LRI combined with clear corneal incision showed reduced efficacy in refractive astigmatism by 47 percent, which is similar to that of paired LRIs where a 48 percent reduction in efficacy was seen. CONCLUSIONS: The short-term effects of a single LRI combined with clear corneal incision on a corneal astigmatism appears to be as effective as performing paired LRIs when combined with cataract incision.
Aged ; Astigmatism/*surgery ; Cornea/*surgery ; Corneal Topography ; Female ; Humans ; Male ; Refractive Surgical Procedures/*methods ; Retrospective Studies ; Statistics, Nonparametric ; Treatment Outcome ; Visual Acuity

Photo refractive keratectomy (PRK) and laser Situ Keratomileusis (LASIK) have been used for over a decade and become popular in China. Principles and characteristics of eye trackers made by several famous foreign manufacturers are introduced in this paper and their developing direction in the future is pointed out too.
Cornea ; surgery ; Eye Movements ; Humans ; Keratomileusis, Laser In Situ ; instrumentation ; Lasers, Excimer ; Myopia ; surgery ; Photography ; instrumentation ; methods ; Photorefractive Keratectomy ; instrumentation ; Refractive Surgical Procedures ; Video Recording

Presbyopia is an age-related condition that progressively decreases the ability to focus on near objects. Minimally invasive surgical techniques have been developed to improve near vision, including laser in situ keratomileuses (LASIK) and corneal inlay. Most have similar approaches using monovision or increasing the depth of focus. Monovision laser refractive surgery is a combination of conventional LASIK, LASIK which creates a multifocal cornea (central near or peripheral near) and aspheric micro-monovision LASIK with a special ablation profile, which develops spherical aberration. Conductive keratoplasty is a method that uses radiofrequency energy to shrink the mid-peripheral corneal stromal tissue. However, it is not used because of regression. A corneal inlay is a small device that is implanted in the corneal flap or pocket made by a femtosecond laser. It is inserted into the non-dominant eye. There are various inlays such as the Flexivue Microlens (refractive), Raindrop (corneal shape-changing), and KAMRA (small-aperture) inlays. However, the safety and effectiveness of these inlays have not been proven over a long follow-up period, so care is required when performing inlay implantation. All presbyopia treatments can improve near vision but also have limitations and side effects such as reduced far vision, contrast sensitivity, or increased glare. Therefore, it is essential to select patients carefully. Mechanisms associated with presbyopia are not fully understood, and presbyopia remains challenging for ophthalmologists.
Contrast Sensitivity ; Cornea ; Corneal Transplantation ; Follow-Up Studies ; Glare ; Humans ; Inlays ; Keratomileusis, Laser In Situ ; Methods ; Presbyopia ; Refractive Surgical Procedures ; Vision, Monocular

PURPOSE: To evaluate the change of accommodation-convergence parameters after implantation of Artisan phakic intraocular lens (PIOL). METHODS: Prospective study for the patients with the Artisan PIOL implantation was performed. A total of 37 patients (3 males and 34 females) enrolled the study. Preoperatively, convergence amplitude, the stimulus accommodative convergence per unit of accommodation (AC/A) ratio and the near point of convergence (NPC) were evaluated. After the Artisan PIOL implantation, the identical evaluations were repeated at 1 week, 1, 3, and 6 months after the surgery. RESULTS: Mean age was 24.3 +/- 4.8 years old, and preoperative refractive error was -8.92 +/- 4.13 diopters (D). After the implantation, mean refractive errors significantly decreased to within +/-1.00 D, and noticeable complications were not found. The convergence amplitude and the stimulus AC/A ratio increased 1 month after the surgery, but progressively stabilized afterward to near preoperative values. NPC didn't show any significant change over follow-up period up to 6 months. CONCLUSIONS: These results regarding implantation of the Artisan PIOL revealed the increase of accommodation-convergence relationship within first 1 month after the surgery, but progressive stabilization was noted during follow-up periods.
*Accommodation, Ocular ; Adult ; *Convergence, Ocular ; Female ; Follow-Up Studies ; Humans ; Lens Implantation, Intraocular/*methods ; Male ; Myopia/*diagnosis/*surgery ; *Phakic Intraocular Lenses ; Postoperative Period ; Prospective Studies ; Refractive Surgical Procedures/methods ; Treatment Outcome ; Visual Acuity ; Young Adult

Laser corneal refractive surgery has become an important treatment to correct ametropia in recent years. Rational medication in the perioperative period is essential to ensure the success of the surgery and to reduce complications. However, in this area there has been no consistent understanding and unified application guide across the world. Experts in Refractive Surgery Group, Ocular Microcirculation Branch of Chinese Society of Microcirculation who are specialized in keratology and optometry had initiated extensive and rigorous discussions and reached a consensus on appropriate medication before, during and after the refractive surgeries. The consensus covers a broad spectrum of commonly used ophthalmic solutions, provides recommendations of routine and enhanced medication on prevention and management of adverse reactions and complications related to the laser corneal refractive surgeries. We hope the consensus serves as a standard perioperative medication regimen for ophthalmologists, helps to ensure the safety and effectiveness of laser corneal refractive surgeries, and improves the quality and outcome of the refractive surgeries.
Anti-Bacterial Agents/therapeutic use* ; Anti-Inflammatory Agents, Non-Steroidal/therapeutic use* ; Asian People/statistics & numerical data* ; China ; Consensus ; Cornea/surgery* ; Drug Therapy/methods* ; Expert Testimony ; Glucocorticoids/therapeutic use* ; Humans ; Lasers ; Ophthalmic Solutions/therapeutic use* ; Perioperative Care ; Refractive Errors/therapy* ; Refractive Surgical Procedures/methods*