|Year : 2022 | Volume
| Issue : 2 | Page : 110-118
The preferences and practices regarding refractive surgeries among Saudi Ophthalmology Society members
Abdullhamid S AlGhamdi1, Rahma A AlGethami2, Nada Ahmad Almalki3, Abdulrahman Mohammed Al-Amri4, Ma'an Al-Barry5
1 Surgery Department, College of Medicine, Taif University, Taif, Saudi Arabia
2 Department of Ophthalmology, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
3 Medical Intern, College of Medicine, Taif University, Taif, Kingdom of Saudi Arabia
4 Surgery Department, College of Medicine, King Khalid University, Abha, Saudi Arabia
5 Surgery Department, College of Medicine, Taibah University, Medina, Saudi Arabia
|Date of Submission||14-Jun-2022|
|Date of Decision||22-Jul-2022|
|Date of Acceptance||01-Aug-2022|
|Date of Web Publication||22-Aug-2022|
Rahma A AlGethami
King Faisal Specialist Hospital and Research Centre, Riyadh
Kingdom of Saudi Arabia
Source of Support: None, Conflict of Interest: None
Background: Refractive errors are the leading cause of visual impairments in the Kingdom of Saudi Arabia (KSA). Laser refractive eye surgeries are getting huge popularity for correcting these visual impairments in KSA and other gulf countries. Aims: The study assessed the preferences and practices regarding refractive surgeries The preferences and practices regarding refractive surgeries among Saudi ophthalmology society members. Setting and Design: A cross-sectional study was conducted using an online questionnaire among the Saudi Ophthalmology Society members. Methods and Materials: The questionnaire was pilot tested and had 28 items that included sociodemographic details and practices related to refractive eye surgery of participating ophthalmologists. Statistical Analysis: The collected data was analyzed using Pearson's Chi-square test to determine the relationship between categorical variables. Results: Excimer laser platform EX500 (Alcon) was the most commonly used refractive surgery system. There were region-wise differences observed in the type of refractive surgery system where surgeons from Central KSA used AMARIS 1050 RS (SCHWIND) (83.4%) and AMARIS 500 (SCHWIND) (68.4%) comparatively more than other regions (P < 0.05). The majority of the eye surgeons (84.4%) used Pentacam comprehensive eye scanner preoperative screening, and corneal topography was the most commonly used preoperative examination method. Only 9.1% of the surgeons had refractive eye surgery on 75%–100% of their patients, and the most commonly preferred refractive eye surgery (RES) by the surgeons in our study was photorefractive keratectomy. Conclusion: The findings showed that refractive eye surgery trends are changing, and surgeons are shifting to more reliable techniques with fewer postsurgical complications.
Keywords: Ophthalmologists, refractive errors, refractive surgeries
|How to cite this article:|
AlGhamdi AS, AlGethami RA, Almalki NA, Al-Amri AM, Al-Barry M. The preferences and practices regarding refractive surgeries among Saudi Ophthalmology Society members. Saudi J Health Sci 2022;11:110-8
|How to cite this URL:|
AlGhamdi AS, AlGethami RA, Almalki NA, Al-Amri AM, Al-Barry M. The preferences and practices regarding refractive surgeries among Saudi Ophthalmology Society members. Saudi J Health Sci [serial online] 2022 [cited 2023 Apr 1];11:110-8. Available from: https://www.saudijhealthsci.org/text.asp?2022/11/2/110/354170
| Introduction|| |
Vision defects due to corneal shape changes are known as refractive errors (REs), and this makes up the second cause of blindness globally. Refractive eye surgeries are commonly performed to correct these errors. In 1970, radial keratotomy was the first refractive eye surgery performed to correct such eye errors. Since then, many improvements in refractive error corrections have been employed, and laser surgery techniques are used widely to correct errors such as myopia, hyperopia, or astigmatism. In myopia, light rays from an object are concentrated anteriorly to the retina leading to nearsightedness. In astigmatism, light rays do not focus at a single point due to the abnormal curvature of the cornea or lens at various meridians, causing uneven focusing, while in hyperopia, the rays are focused posterior to the retina, causing farsightedness.,,
In the Kingdom of Saudi Arabia (KSA), studies are limited that assessed the prevalence of REs in the adult population. A study done in Arar city had reported that the prevalence of REs was 45.8%, in which myopia was the most common type of RE (24.4%), followed by hyperopia (11.9%) and astigmatism (9.5%). Epidemiological studies conducted in other parts of KSA show that RE is the leading cause of visual impairments.,, The quality of life in people suffering from visual impairments is compromised where they experience difficulties in physical function, emotional distress, and poor social life. Refractive surgery improves the quality of patients' life and daily work in addition to spectacle independence. Furthermore, corneal surgery remains the mainstay of refractive correction since the cornea is the most accessible part of the eye and provides two-thirds of the eye's refractive power. Photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) are still used among these refractive eye surgery techniques. Laser refractive surgery is now generally accepted as effective and safe, providing the most predictable outcomes for patients diagnosed with low-to-moderate amounts of refractive error. However, LASIK has got some drawbacks, such as epithelial ingrowth, corneal ectasia, and corneal flap complications. To compensate for these drawbacks, laser-assisted subepithelial keratomileusis (LASEK) was first introduced in 1990. Laser eye surgeries are rapidly evolving, and many promising surgical options have been tried, such as phakic intraocular lenses (p-IOLs), epithelial laser keratomileusis, femtosecond lenticule extraction, and customized transepithelial no-touch, and small incision lenticule extraction., It is thus important to identify the needs for treatment and rehabilitation services by gathering essential data on the frequency of REs from the population.
Studies show that the preferences of eye surgeons are changing with the development and availability of new and reliable eye surgery techniques., Some eye surgeons have the impression that the clinical characteristics of patients have changed over time and new technology needs to be adopted to overcome these changes. Shreds of evidence show that most of the patients are satisfied with the outcomes of laser eye surgeries, and the factors that determine the satisfaction and dissatisfaction are largely unpredictable and subjective., The choice of type of refractive eye surgery is shared decision-making between the patient and the doctor. These surgeries are not usually covered by health insurance, and the cost varies according to the country's market, the technology used, and the surgeon's preferences. A study shows that the majority of the patients seek refractive eye surgery based on their preferences and suggestion from experts such as family physicians or ophthalmologists. There is a need to identify current practices in refractive surgery and compare them with past practices in the KSA. This is crucial for predicting future challenges and changes in eye surgery and health-care policy. The popularity of refractive eye surgeries is showing an upward trend, and there is a lack of studies in our region about the trends in these surgeries. Our aim in this study is to assess the preferences and practices regarding refractive surgery trends among Saudi ophthalmology society (SOS) members.
| Subjects and methods|| |
A cross-sectional study was conducted using a pretested questionnaire among ophthalmologists in the KSA. The questionnaire was applied during the Saudi Ophthalmology Congress, 2020, after identifying the E-mail id of all the registered member ophthalmologists of the SOS. Only members of the SOS who gave consent to participate after understanding the need and benefits of the study were included. Ophthalmologists who were not members of SOS and who did not give consent were excluded. The questionnaire was sent using a link to an online survey form (Google Forms) to collect the required data. A mixture of convenience and snowball sampling was done to collect the data. Responses from 77 ophthalmologists who fulfilled the above eligibility criteria were thus included in our analysis.
The questionnaire consisted of two parts. The first part collected information related to sociodemographic characteristics of ophthalmologists (6 items), and the second part included items related to refractive eye surgery practices (18 items). The questionnaire was pretested and piloted among ten ophthalmologists before sending for final data collection.
All the collected information was first cleaned and then tabulated on a Microsoft Excel sheet and transferred to IBM Statistical Package for the Social Sciences, version 23 (SPSS Inc., Chicago, IL, USA) for analysis. Descriptive statistics in the form of frequencies and percentages using suitable tables and figures were used to represent categorical data. Pearson's Chi-square test was used to find the relationship between categorical variables. P <0.05 was considered statistically significant.
| Results|| |
The analysis showed that the majority of the surgeons belonged to the age of 40–49 years (49.4%) and were Saudi citizens (90.9%). The type of work setting where refractive surgeons showed that 59.7% worked in private surgery hospitals or clinics, 9.1% worked in government hospitals, whereas 23.4% worked in both private and government hospitals. The majority of the surgeons practiced in Saudi Arabia (96.1%), and 41.6% had an experience of 10–19 years in refractory surgery. It was found that 46.8% had done 16–25 refractive surgeries per month [Table 1].
Refractive surgery systems
The most commonly used excimer laser platform is EX500 (Alcon) (27.3%) followed by AMARIS 500 (SCHWIND) (24.7%). The usage of EX500 (Alcon) was found to be comparatively more used by surgeons of the age group <40 years (42.1%), whereas AMARIS 500 (SCHWIND) was used more commonly by surgeons of age group 40–49 years (52.4%) (P < 0.05) [Table 2]. It was also observed that surgeons from Central KSA used AMARIS 1050 RS (SCHWIND) (83.4%) and AMARIS 500 (SCHWIND) (68.4%) comparatively more than other regions, whereas those from Western KSA used MEL 90 (Carl Zeiss Meditec AG) more than others (71.4%), which showed a statistically significant association (P = 0.005) [Table 3].
|Table 2: Refractive surgery equipment and their relationship with characteristics of surgeons|
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The most commonly used femtosecond laser (FSL) was Intralase 150 HZ (28.5%), followed by WaveLight FS200 FSL system (20.8%), which was found to be more used by surgeons from Central KSA and Western KSA compared to others (P = 0.006). It was found that the majority of the surgeons did not use any manual microkeratome [Table 2].
Preoperative diagnostics and examination
The most preferred preoperative topographic diagnostic device used for preoperative screening was Pentacam comprehensive eye scanner (CES) (84.4%), and the preoperative wavefront diagnostic device for treatment planning was Alcon's Contoura Vision (22.1%). For preoperative examination, corneal topography was the most commonly performed method (89.6%) of the surgeons, followed by thinnest corneal pachymetry (87%) and corneal tomography (70.1%), and the less commonly done was continuity of Placido mires (16.9%) [Table 4].
It was found that 72.7% of the surgeons reported that all factors such as cylindrical power, higher-order abrasion, spherical equivalent, spherical power, postoperative expected keratometry, and postoperative expected residual stromal bed were influencing factors for undertaking RES. It was reported by 79.2% of the surgeons that only <25% of their patients underwent RES, whereas 9.1% mentioned that they RES on 75%–100% of their patients [Figure 1].
|Figure 1: Frequencies for influencing factors for RES and patients who underwent RES, RES: Refractive eye surgery|
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When we assessed the treatment chosen for presbyopia, 59.7% and 26% of the surgeons reported it as “reading glasses” and “refractive lens exchange (RLE) with presbyopia IOL, respectively.” It was found that 96.1% and 92.2% of the surgeons did not undergo any corneal surface excimer procedure and intracorneal inlay for their patients. The most commonly performed multifocal IOLs for presbyopia was “the PanOptix” (33.8%), followed by “the AT LISA tri 839 MP” (26%). It was reported by 98.7% of the surgeons that they did not use any accommodating IOLs for presbyopia [Figure 2].
The assessment of technique for myopia showed that PRK was the most preferred for myopia <4.00 D (68.8%) and 4.00–8.00 D (53.2%). At the same time, it was phakic intraocular lens (p-IOL) implants for myopia 8.00–12.00 D (80.5%) and >12.00 D (92.2%). When we asked the preferable p-IOLs, it was found that the majority (90.9%) of the surgeons preferred Visian implantable collamer lens and posterior chamber intraocular lens [Table 5].
The most commonly preferred RES by the surgeons in our study was PRK, which was more reported by surgeons with 9 years or less experience (P = 0.020). Laser in situ keratomileusis (LASIK) and intrastromal corneal rings were more preferred by non-Saudi surgeons than Saudi Surgeons (P < 0.05) [Table 6].
|Table 6: Refractive eye surgery and its relationship with characteristics of surgeons|
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Laser-assisted subepithelial keratomileusis surgery-related factors
For LASIK surgery, the most used corneal flap creation was FSL (94.8%), which was comparatively more used by surgeons of age <49 years (>40 and 41–49 years) (P < 0.001). The most commonly preferred corneal flap thickness was 110 um (66.2%), which was significantly more used by surgeons who had an experience of 10 years and more (P < 0.001). The most commonly used corneal flap diameter for myopia was 8.50 mm (45.5%), which was significantly higher in surgeons who had an experience of 10–19 years (51.4%) (P = 0.015). Whereas the commonly used corneal flap diameter for hyperopia was 9.00 mm (84.4%), (61.5%) (P = 0.010). The most preferred residual stromal bed thickness (RSBT) limitation for LASIK surgery was 351–400 um (40.3%), which was comparatively more seen in surgeons of age group 50–59 years (48.4%) (P = 0.020) [Table 7].
|Table 7: Laser in situ keratomileusis surgery-related factors and its relationship with characteristics of surgeons|
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It was reported by 88.3% of surgeons that the percentage of postrefractive surgery enhancement performed was <2%, and this was significantly higher in surgeons aged 40–49 years (52.9%), Saudi surgeons (94.1%), and those who had experience in RES of <5 years (28%) (P < 0.05). It was found that 81.8% of the surgeons <25% of their cataract patients received premium IOL implant, and 68.8% of them preferred PRK procedure mitomycin application for all cases. Seventy-four percent of surgeons reported that they do not apply mitomycin during a PRK [Table 7].
| Discussion|| |
This study assessed the current practices related to refractive surgery among SOS members. The findings showed that PRK surgery was the most commonly performed surgery for myopia - 8.00 diopter reported by the participants. This is in contrast to a recent study conducted by Alsabaani et al. in KSA, which said that 50% and 45% of the ophthalmologists preferred LASIK and PRK, respectively. Laser in situ keratomileusis (LASIK) is one of the commonly preferred procedures for refractive eye surgery worldwide as it has the advantage of maintaining central corneal epithelium compared to PRK., One of the reasons to avoid LASIK by sour study participants could be minimizing the corneal flap-related complications during surgery that are difficult to treat. However, p-IOL implants were the most preferred technique for myopia –8 to –12 D by our study participants, and this may be to minimize the incidence of corneal ectasia, postoperative refractive error, and myopic regression. This is similar to the findings of Ahn et al., which reported that 92% of the surgeons preferred p-IOLs for myopia more than –8 D. The most commonly used excimer laser platform was EX500 (Alcon) (27.3%), followed by AMARIS 500 (SCHWIND) (24.7%). The excimer laser system had been in use since 1987, and now, there are various commercially available systems depending on the country. In our study, there were variations observed in the usage of excimer laser systems between different regions. A study done in Riyadh had reported that 30% and 15% of eye surgeons used Alcon and Nidek laser systems and 50% did not remember what systems they used for refractive surgery. EX500 systems are one of the latest systems that many surgeons prefer due to their advantages, such as maintaining a more natural corneal shape surgery, decreased aberration induced during the procedure, and topography-guided customized treatment using a 6D tracking system. Schwind Amaris has a super-Gaussian ablative spot profile and has major advantages such as short treatment time (<2 s) and has the ability to maintain the preoperative levels of ocular higher-order aberrations due to its aspheric ablation algorithm.
In our study, the majority of the surgeon used Pentacam CES for preoperative screening. Evidence shows that refractive indices on the Pentacam system are reliable preoperative topography diagnostic devices. A study done by Uçakhan et al. reported that Pentacam CES showed better reproducibility in measuring central corneal thickness (CCT) compared to ultrasound pachymetry among moderately keratoconic eyes. The most commonly used preoperative wavefront diagnostic device by our participants were Alcon's Contoura Vision and the Combi Wavefront Analyzer. It was demonstrated by Heidari et al. that Corneal wavefront indices from Scheimpflug, Scheimpflug/Placido, and Hartmann–Shack devices have better validity and higher diagnostic ability for keratoconus (KCN) patients when compared to subclinical KCN. The majority of the surgeons used corneal topography and thinnest corneal pachymetry for preoperative examination. Corneal topography is used to evaluate the anterior curvature of the cornea, whereas tomography is used to measure posterior curvature. Pachymetry imaging is often preferred by eye surgeons for CCT measurement due to its easiness to use, reproducibility, and acceptable cost.
FSL was used for corneal flap creations by the majority of the surgeons in our study. FSL is rapidly gaining popularity due to the superior consistency and predictability for corneal incisions and anterior capsulorhexis. Our study observed that the majority of the surgeon preferred 110 μm thickness for corneal flap in LASIK, whereas only minimum participants preferred 130 μm. These findings are in contrast to findings from Korea, where the preferred thickness was 130 μm. Some surgeons preferred thinner flaps, which might be because a thin flap can be created more easily using an FSL. The less use of mechanical microkeratomes by the refractive surgeons could be because they tend to create uneven thickness for meniscus-shaped corneal flaps compared to FSL, which gives a more uniform planar flap. The most commonly preferred flap diameter for myopia using LASIK was 8.5 μm. It is very crucial to consider flap size to the corneal diameter when opting for a LASIK as a larger corneal diameter may give tear deficiency after the surgery. The commonly used RSBT for LASIK in our study was 351–400 μm (40.3%) followed by 301–350 μm (37.7%). A study done in the USA reported that the commonly preferred RSBT was 300 μm (43%) and 250 μm (39%). The Korean study showed that 66.7% preferred 300–350 μm as the minimum RSBT for LASIK, which is more than our study findings. Our study participants preferred a thicker RSBT, which could be related to avoiding corneal ectasia related to refractive surgery.
REs such as undercorrection, overcorrection, regression, and surgically induced astigmatism could happen after refractive surgeries. In our study, the percentage of postrefractive surgery enhancement performed was minimal (<2%) as reported by the majority of the surgeons. This indicates that the incidence of REs was less reported by our study participants, which could not be completely related to the technique and devices used for surgery as REs depend on many other factors. It was reported by < 25% of the surgeons that they gave premium IOL (p-IOL) implants for cataract patients. The p-IOLs have special refractive properties and aspheric design, are biocompatible, and would provide clear vision at near and distant focal points without additional spectacle correction compared to traditional IOLs. In our study, only 26% did RLE with IOLs for presbyopia, and the majority of the surgeons prescribed reading glasses for such patients. Surgical procedures are expensive when compared to other nonsurgical methods such as spectacles and contact lenses, and this could be the reason why the majority of surgeons prescribed spectacles for presbyopia patients.
Our study has some limitations; first, we used a self-reported online questionnaire with multiple choices, resulting in response bias and social desirability bias. Second, our sample size was not big enough, and we used a mixture of convincing and snowball sampling methods that would have resulted in sampling bias. Third, we had a very limited response rate as this was an anonymous survey.
| Conclusion|| |
The current study showed that the most commonly preferred refractive surgery was PRK, which shows that trends are shifting from LASIK to other newer methods. The use of surgical procedures for correcting presbyopia was less among our study participants. Eye surgeons need to be updated with newer technologies and devices that deliver higher accuracy, repeatability, consistency, and also patient safety. We suggest conducting a larger prospective study involving a bigger sample of eye surgeons to truly assess the latest trends in refractive surgery in KSA.
The authors thank the participants of this work for their cooperation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Naidoo KS, Leasher J, Bourne RR, Flaxman SR, Jonas JB, Keeffe J, et al.
Global vision impairment and blindness due to uncorrected refractive error, 1990-2010. Optom Vis Sci 2016;93:227-34.
McGhee CN, Ormonde S, Kohnen T, Lawless M, Brahma A, Comaish I. The surgical correction of moderate hypermetropia: The management controversy. Br J Ophthalmol 2002;86:815-22.
Brahma A, McGhee CN. Surgical correction of refractive errors. J R Soc Med 2000;93:118-23.
Kohnen T. Advances in the surgical correction of hyperopia. J Cataract Refract Surg 1998;24:1-2.
Parrey MU, Elmorsy E. Prevalence and pattern of refractive errors among Saudi adults. Pak J Med Sci 2019;35:394-8.
Al-Shaaln FF, Bakrman MA, Ibrahim AM, Aljoudi AS. Prevalence and causes of visual impairment among Saudi adults attending primary health care centers in Northern Saudi Arabia. Ann Saudi Med 2011;31:473-80.
] [Full text]
Parrey MU, Alswelmi FK. Prevalence and causes of visual impairment among Saudi adults. Pak J Med Sci 2017;33:167-71.
Tabbara KF, El-Sheikh HF, Shawaf SS. Pattern of childhood blindness at a referral center in Saudi Arabia. Ann Saudi Med 2005;25:18-21.
] [Full text]
Tanna AP. Growing evidence of the importance of the macula in glaucoma. JAMA Ophthalmol 2017;135:747-8.
Schmack I, Auffarth GU, Epstein D, Holzer MP. Refractive surgery trends and practice style changes in Germany over a 3-year period. J Refract Surg 2010;26:202-8.
Sugar A, Rapuano CJ, Culbertson WW, Huang D, Varley GA, Agapitos PJ, et al.
Laser in situ
keratomileusis for myopia and astigmatism: Safety and efficacy: A report by the American Academy of Ophthalmology. Ophthalmology 2002;109:175-87.
Melki SA, Azar DT. LASIK complications: Etiology, management, and prevention. Surv Ophthalmol 2001;46:95-116.
Camellin M. Laser epithelial keratomileusis for myopia. J Refract Surg 2003;19:666-70.
Ahn JH, Kim DH, Shyn KH. Investigation of the changes in refractive surgery trends in Korea. Korean J Ophthalmol 2018;32:8-15.
Kuo IC. Trends in refractive surgery at an academic center: 2007-2009. BMC Ophthalmol 2011;11:11.
Kim TI, Alió Del Barrio JL, Wilkins M, Cochener B, Ang M. Refractive surgery. Lancet 2019;393:2085-98.
Sandoval HP, Donnenfeld ED, Kohnen T, Lindstrom RL, Potvin R, Tremblay DM, et al.
Modern laser in situ
keratomileusis outcomes. J Cataract Refract Surg 2016;42:1224-34.
Pasquali TA, Smadja D, Savetsky MJ, Reggiani Mello GH, Alkhawaldeh F, Krueger RR. Long-term follow-up after laser vision correction in physicians: Quality of life and patient satisfaction. J Cataract Refract Surg 2014;40:395-402.
Reyna VF. A theory of medical decision making and health: Fuzzy trace theory. Med Decis Making 2008;28:850-65.
Alsabaani N, Alshehri MS, AlFlan MA, Awadalla NJ. Prevalence of laser refractive surgery among ophthalmologists in Saudi Arabia. Saudi J Ophthalmol 2020;34:116-9. [Full text]
Ambrósio R Jr., Wilson S. LASIK versus LASEK versus PRK: Advantages and indications. Semin Ophthalmol 2003;18:2-10.
Ku M, Shyn KH. 2006 Survey for KSCRS members: Current trends in refractive surgery in Korea. J Korean Ophthalmol Soc 2009;50:182-8.
Huang D, Schallhorn SC, Sugar A, Farjo AA, Majmudar PA, Trattler WB, et al.
Phakic intraocular lens implantation for the correction of myopia: A report by the American academy of ophthalmology. Ophthalmology 2009;116:2244-58.
El Bahrawy M, Alió JL. Excimer laser 6th
generation: State of the art and refractive surgical outcomes. Eye Vis (Lond) 2015;2:6.
Arbelaez MC, Aslanides IM, Barraquer C, Carones F, Feuermannova A, Neuhann T, et al.
LASIK for myopia and astigmatism using the SCHWIND AMARIS excimer laser: An international multicenter trial. J Refract Surg 2010;26:88-98.
Motlagh MN, Moshirfar M, Murri MS, Skanchy DF, Momeni-Moghaddam H, Ronquillo YC, et al.
Pentacam® corneal tomography for screening of refractive surgery candidates: A review of the literature, Part I. Med Hypothesis Discov Innov Ophthalmol 2019;8:177-203.
Uçakhan OO, Ozkan M, Kanpolat A. Corneal thickness measurements in normal and keratoconic eyes: Pentacam comprehensive eye scanner versus noncontact specular microscopy and ultrasound pachymetry. J Cataract Refract Surg 2006;32:970-7.
Heidari Z, Mohammadpour M, Hashemi H, Jafarzadehpur E, Moghaddasi A, Yaseri M, et al.
Early diagnosis of subclinical keratoconus by wavefront parameters using scheimpflug, placido and hartmann-shack based devices. Int Ophthalmol 2020;40:1659-71.
Fan R, Chan TC, Prakash G, Jhanji V. Applications of corneal topography and tomography: A review. Clin Exp Ophthalmol 2018;46:133-46.
Belovay GW, Goldberg I. The thick and thin of the central corneal thickness in glaucoma. Eye (Lond) 2018;32:915-23.
Nagy ZZ, McAlinden C. Femtosecond laser cataract surgery. Eye Vis (Lond) 2015;2:11.
Kim CY, Song JH, Na KS, Chung SH, Joo CK. Factors influencing corneal flap thickness in laser in situ
keratomileusis with a femtosecond laser. Korean J Ophthalmol 2011;25:8-14.
Tai YC, Sun CC. Effects of flap diameter on dry eye parameters and corneal sensation after femtosecond laser-assisted LASIK. Taiwan J Ophthalmol 2019;9:166-72.
] [Full text]
Lundström M, Dickman M, Henry Y, Manning S, Rosen P, Tassignon MJ, et al.
Risk factors for refractive error after cataract surgery: Analysis of 282 811 cataract extractions reported to the European registry of quality outcomes for cataract and refractive surgery. J Cataract Refract Surg 2018;44:447-52.
Zvorničanin J, Zvorničanin E. Premium intraocular lenses: The past, present and future. J Curr Ophthalmol 2018;30:287-96.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]