Evaluation of the effect of artificial tears on corneal epithelial thickness changes after photorefractive keratectomy.

PURPOSE: This study aimed to evaluate the corneal epithelial thickness changes after photorefractive keratectomy (PRK) and the impact of long-term artificial tear usage on epithelial thickness changes in these patients. METHODS: This study was performed on 71 patients (142 eyes) without dry eye disease who received PRK for myopic refractive correction. The corneal epithelial thickness profile was obtained before, one, three, and six months after surgery using anterior segment optical coherence tomography. Patients were randomly divided into two groups: group A, who received preservative-free artificial tears post-surgery, and group B, who did not receive artificial tears. RESULTS: The epithelial thickness decreased universally in the first month and then increased in the 3- and 6-month follow-ups. Group A had a significantly thicker epithelium in central, paracentral, and midperipheral zones compared with group B in the 3-month follow-up. In the 6-month follow-up, no significant differences were detected between groups. At the last follow-up, the central, paracentral, and midperipheral zone epithelial thicknesses in all patients were significantly higher than preoperative values, but peripheral zone thickness only increased to preoperative values. CONCLUSIONS: Patients using artificial tears showed a faster thickening, especially in the central and paracentral zones, but there were no significant differences between the two groups in the final follow-up. Artificial tear usage may increase the rate of the epithelial remodeling process in post-PRK patients without significantly altering the final epithelial thickness profile. Further studies are warranted to evaluate the influence of different factors on epithelial remodeling.

A joinpoint and age-period-cohort analysis of ocular cancer secular trends in Iran from 2004 to 2016.

Investigating secular trends of ocular cancer registration in Iran. After acquiring Iranian national population-based cancer registry data, trends of age-standardised incidence rates (ASIR) of ocular cancers and annual percent changes (APC) between 2004 and 2016 were analysed in age groups, gender, topography and morphology types with joinpoint regression analysis. Age, period, and cohort effects on incidence rates were estimated by age-period-cohort model. Geographic distribution of ASIR was assessed using GIS. Overall ASIR of ocular cancers was 16.04/100,000 (95% CI 15.77-16.32). Joinpoint regression analysis showed a significant increase of ASIR between 2004 and 2009 for males (APC = 5.5, 95% CI 0.9-10.2), ages over 50 years (APC = 5.2, 1.2-9.4), skin/canthus/adnexal cancers (APC = 4.2, 0.8-7.7), and carcinomas/adenocarcinomas (APC = 4.3, 0.6-8.1); however, between 2009 and 2016 a declining trend was observed in all investigated variables. ASIR of retinoblastoma was significantly increased (averaged APC = 20.7, 9-33.7) between 2004 and 2016. age-period-cohort analyses showed that incidence rates of ocular cancers significantly increased with aging, time periods, and birth cohort effects (p < 0.001). ASIR varied from 6.7/100,000 to 21.7/100,000 in Iran. Excepting retinoblastoma, all ocular cancer incidence trends were downward over a 13-year period; however, it was increasing between 2004 and 2009 cancer. ASIR was significant aging in Iran.

Applications of Haptic Technology, Virtual Reality, and Artificial Intelligence in Medical Training During the COVID-19 Pandemic.

This paper examines how haptic technology, virtual reality, and artificial intelligence help to reduce the physical contact in medical training during the COVID-19 Pandemic. Notably, any mistake made by the trainees during the education process might lead to undesired complications for the patient. Therefore, training of the medical skills to the trainees have always been a challenging issue for the expert surgeons, and this is even more challenging in pandemics. The current method of surgery training needs the novice surgeons to attend some courses, watch some procedure, and conduct their initial operations under the direct supervision of an expert surgeon. Owing to the requirement of physical contact in this method of medical training, the involved people including the novice and expert surgeons confront a potential risk of infection to the virus. This survey paper reviews recent technological breakthroughs along with new areas in which assistive technologies might provide a viable solution to reduce the physical contact in the medical institutes during the COVID-19 pandemic and similar crises.

Geographical inequality in cataract surgery among Iranians between 2006 and 2011.

BACKGROUND: Cataract surgery is a highly cost-effective intervention for sight restoration but inequalities exist in its use which health care systems should aim to reduce. AIMS: This study aimed to measure the level of inequality in cataract surgery use and the changes in inequality between 2006 and 2011 in the Islamic Republic of Iran. METHODS: A number of metrics, including ranges and indexes based on Lorenz curves (Gini, concentration and dissimilarity indexes), were used to measure the inequality in cataract surgery use among Iranians in 2006 and 2011. Cataract surgical numbers and socioeconomic data were obtained from a province-based survey and the national census database. RESULTS: Significant inter-provincial and inter-regional differences were found in cataract surgical proportions. South Khorasan province had the lowest cataract surgical rate in 2006 and 2011, while Tehran province had the highest rate in both years. Inequality in the distribution of cataract surgery services decreased between 2006 and 2011: the Gini, concentration and dissimilarity indexes decreased by 0.028, 0.03 and 0.037, respectively. However, cataract surgery delivery remained in favour of the better-off provinces. CONCLUSIONS: To reduce this inequality, policy-makers should improve financial and physical access to cataract surgery, especially in the relatively deprived provinces, and tackle physician-induced demand.

Refractive surgery: the most cost-saving technique in refractive errors correction.

AIM: To compare the lifetime and annual economic burden of spectacles, contact lenses, and refractive surgery in correction of refractive errors. METHODS: This is a cross-sectional study with convenience sampling which 120 patients were interviewed in a tertiary referral hospital in the Iranian health care system. The bottom-up based cost of illness approach was estimated using a face-to-face interview to assess the direct and indirect cost of different refractive errors correction of any correction technologies. RESULTS: Correction with spectacle imposes a total direct cost of US dollar (US$) 342.5 (±8.41) per year and US$9373.5 (±230.1) per lifetime to each patient. These figures for the contact lenses were obtained US$198.3 (±0.12) and US$5203.1 (±256.3) and for refractive surgery were obtained US$19.1 (±1.2) and US$568.1 (±64.6), respectively. Overall, based on age-adjusted prevalence rates, astigmatism had the highest share of refractive errors economic burden with a lifetime direct cost of slightly less than US$5.49 billion, while hyperopia and myopia imposed less than US$5.24 and 4.2 billion on patients, respectively. The annually imposed cost on each individual Iranian patient with refractive errors is US$308.5. CONCLUSION: Based on 18mo post refractive surgery course observation, which is generalized to whole life, refractive surgery significantly imposed much less cost compared with spectacles and contact lenses. Refractive errors among Iranians result in considerable economic burden. Using the refractive surgery instead of other two correction methods has the ability to reduce this economic loss in the future.

Topographic typology in a consecutive series of refractive surgery candidates.

PURPOSE: The term 'keratoconus (KC) suspect' is used as a blanket term to refer to any deviation of virgin cornea shape toward KC features. We intend to subclassify such topographies in meaningful and informative designations. METHODS: Pentacam corneal topographies of 199 consecutive refractive surgery candidates (398 eyes) are examined. Features of steepness, inferior-superior asymmetry, focal steepening, thinning, and bounded anterior or posterior elevations are observed in the quad map. Scissoring on retinoscopy, loss of best spectacle-corrected visual acuity, and iron ring deposition were looked for. Through iterative observation and refinement of classification criteria-partly taken from the literature-all eyes were designated a specific topographic diagnosis, i.e., circumventing the usage of the expression KC 'suspect'. RESULTS: Topographies of 308, 48, 21, 13, 6, 1, and 1 (collectively 398 eyes) were designated: normal, 'atypical normal,' forme fruste KC, posterior KC, subclinical/mild KC, superior KC, and pseudo-KC, respectively. CONCLUSION: Current imaging modalities of the cornea and our accumulated experience in refractive science allow assignment of distinctive designations for abnormal corneal shapes along the topography spectrum. We devised and used the expressions: normal, atypical normal, forme fruste (arrested-incomplete) KC, posterior KC, subclinical (active latent) KC, superior KC, and pseudo-keratoconus. Identification of 1.5% (mild) KC highlights the importance of screening for ultraviolet cross-linkage candidacy in refractive surgery referrals.

Refractive lens exchange and piggyback intraocular lens implantation in nanophthalmos: Visual and structural outcomes.

PURPOSE: To evaluate the best piggyback intraocular lens (IOL) implantation method and the outcomes in nanophthalmos eyes and to define the postoperative structural changes. SETTING: Farabi Eye Hospital, Tehran, Iran. DESIGN: Prospective case series. METHODS: Candidates for refractive surgery who were nanophthalmic were recruited. Patients had refractive lens exchange followed by implantation of both IOLs in the bag or 1 IOL in the bag and 1 IOL in the sulcus. The baseline and follow-up visual acuity, refractive status, and structural Scheimpflug imaging were evaluated. Ultrasound biomicroscopy (UBM) was performed 6 months postoperatively. RESULTS: The study comprised 9 nanophthalmic patients (18 eyes) with a mean preoperative uncorrected distance visual acuity (UDVA) of 1.53 logarithm of the minimum angle of resolution (logMAR) ± 0.3 (SD), mean corrected distance visual acuity (CDVA) of 0.34 ± 0.2 logMAR, and mean spherical equivalent (SE) of +13.55 ± 4.0 diopters (D). The mean postoperative UDVA improved from baseline. There was no significant difference in the mean UDVA and CDVA between the 2 IOL groups. Postoperatively, both groups had a significant improvement in SE, a significant rise in anterior chamber depth and angle, and similar UBM measurements. CONCLUSIONS: Piggyback IOL implantation was an effective refractive procedure in nanophthalmic eyes. Both implantation methods resulted in similar outcomes; however, the small number of patients in each group made it less likely that possible differences would be found. The increase in angle values might help prevent the development of closed-angle glaucoma.

Outcome of Single-piece Intraocular Lens Sulcus Implantation following Posterior Capsular Rupture during Phacoemulsification.

PURPOSE: To assess the safety and outcome of single-piece posterior chamber intraocular lens (PC-IOL) implantation in the ciliary sulcus following posterior capsular rupture during cataract surgery. METHODS: Patients with posterior capsular rupture during cataract surgery with a single-piece acrylic IOL implanted into the ciliary sulcus were studied. Complete ocular examinations were performed after 6 months postoperatively. RESULTS: Twenty-four eyes were included. Mean follow-up duration was 8.33 ± 2.33 months. There was no significant difference between preoperative and postoperative keratometric cylinder or intraocular pressure. Visual acuity of 87.50% of patients was ≥20/40 after surgery. Complications included foveopathy (10 eyes), iris transillumination defect (4 eyes), iris chafing (2 eyes), pigmented keratic precipitate (KP) (4 eyes), clinical IOL tilt (6 eyes), endothelial pigment dusting (14 eyes), IOL pigment dusting (17 eyes), iris bowing (6 eyes), IOL decentration (4 eyes), and IOL tilt detected with ultrasonography biomicroscopy (UBM) (4 eyes). IOL pigment dusting was significantly higher in eyes with short axial lengths, high IOL power, small sulcus-to-sulcus (STS) diameter, large STS IOL diameter mismatch, and small anterior chamber depth and angle. Significant relationships were observed between pigmented KP with small STS diameter and large STS IOL diameter mismatch, UBM and clinical IOL tilt with large anterior chamber depth and between iris transillumination defect and STS IOL diameter mismatch. CONCLUSION: This implantation is associated with higher incidence of complications. Single-piece acrylic IOLs are not designed for sulcus implantation. However, they may be used in eyes with longer axial length if the 3-piece IOL is not available.

A survey of ophthalmologists and gynecologists regarding termination of pregnancy and choice of delivery mode in the presence of eye diseases.

PURPOSE: To evaluate and compare the attitudes of ophthalmologists and gynecologists in suggesting appropriate approach to pregnancy in different ocular conditions. METHODS: Specialty-specific questionnaires on delivery mode and abortion indications for ophthalmic patients (refractive, vascular, oncologic, retinal, glaucoma, postoperation, posttrauma, and infectious) were designed and distributed among physician staff of Farabi Eye Hospital and Yas Women Hospital in Tehran. Attitudes and preferences of the ophthalmologists and gynecologists were quantified and compared. RESULTS: Participants were 29 ophthalmologists and 19 gynecologists. Their mean age was 49.73 ± 7.57 and 46.79 ± 1.36 years, respectively. More than 50-70% ophthalmologists were in favor of normal vaginal delivery (NVD) in all ocular diseases. All gynecologists (100%) expressed their need for an ophthalmologist's opinion for decision-making. Ophthalmologists' top choices for conditions potentially requiring a caesarean section were corneal transplants (34.5%), high myopia (23%), retinal detachment (29%), and orbital tumors (34.5%), while two gynecologists recommended abortion in the presence of intraocular and orbital tumors and retinal detachment. In the case of a history of refractive surgery, orbital tumor and intraocular tumor, ophthalmologists recommend NVD over caesarean section twice as much as their gynecologist peers. For history of retinal detachment, glaucoma, retinal vascular accident and intraocular hemorrhage, no single gynecologist recommend NVD. The corresponding figure for ophthalmologist-recommended NVD were 67, 84, 72, and 81%. CONCLUSIONS: There is extreme inconsistency among ophthalmologists and gynecologists in managing ophthalmic-obstetric scenarios, especially for caesarean section indications. Clinical guideline development and consultation for decision-making in challenging cases are recommended.

Post-photorefractive Keratectomy Pain and Corneal Sub-basal Nerve Density.

PURPOSE: The perceived and reported pain of patients receiving photorefractive keratectomy (PRK) widely varies. We assessed the potential role of the subbasal nerve plexus density as a predictor of postoperative pain level. Consecutive patients scheduled to undergo PRK at the Refractive Surgery Clinic of Farabi Eye Hospital, Tehran, were approached. METHODS: Forty-nine myopic left eyes from 49 patients who consented to undergo scanning slit confocal microscopy assessments preoperatively were included. ImageJ (1.48v) was used to measure the captured subbasal nerve length. Postoperative pain intensity was assessed by the Visual Analog Scale (VAS) (score range: 0 for no pain to 10 for the maximum possible) on the next day of surgery. RESULTS: The mean age of the patients was 27.55 (range: 19-40) years. The median reported pain level was 5. Approximately 32.7% of the subjects reported a pain score of 6 or higher. Mean nerve density was 19.54 (range: 14.34-24.73) mm/mm2. Nerve density was not correlated with the reported intensity of pain (P = 0.172). However, pain was correlated with the reported ocular discomfort, i.e., a pooled index of foreign body sensation, photophobia, burning sensation, and tearing (P < 0.001), and also with the pooled index of ocular inflammatory signs (conjunctival injection and eyelid edema) (P = 0.027). CONCLUSION: Crude density of corneal nerves may not be a good predictor of post-PRK pain while wearing bandage contact lenses. The predominant pain mechanism appears to be of an inflammatory nature (not nociceptive or neuropathic).

Visual, Keratometric and Corneal Biomechanical Changes after Intacs SK Implantation for Moderate to Severe Keratoconus.

PURPOSE: To report visual outcomes and corneal biomechanical changes after femtosecond-assisted Intacs SK implantation in keratoconic eyes. METHODS: This prospective interventional case series is comprised of 32 keratoconic eyes of 25 patients with mean age of 23.8 ± 5.4 years. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refraction, manifest refraction spherical equivalent (MRSE), keratometry, central corneal thickness (CCT), corneal hysteresis (CH) and corneal resistance factor (CRF) were measured preoperatively, and 1, 3 and 6 months postoperatively. RESULTS: Mean UDVA improved from 0.81 ± 0.3 LogMAR preoperatively to 0.53 ± 0.2 LogMAR six months postoperatively (P < 0.001). At 6 months, MRSE was significantly reduced only in eyes with moderate KCN (mean change, +2.61 ± 0.54 diopter [D]; P< 0.001). A significant improvement in sphere (mean change, +1.92 ± 0.37 D; P< 0.001) and mean keratometry (mean change, -3.34 ± 0.47D; P< 0.001) were observed. CCT increased from 446.1 ± 38 µm preoperatively to 462.2 ± 50 µm at six months (P < .001). CRF decreased from 6.5 ± 1.6 mmHg to 5.9 ± 1.1 mmHg six months after surgery (P = 0.02). CDVA, refractive cylinder and CH did not change significantly (P = 0.48, 0.203 and 0.55, respectively). Linear regression analysis disclosed that a decrease in CCT and moderate KCN are associated with higher CRF (standardized B,-0.513 and 0.314;P= 0.004 and 0.024, respectively; Adjusted R square = 0.353). CONCLUSION: Visual, refractive and keratometric indices remarkably improved in a parallel fashion. CRF was inversely associated with CCT. Changes in CRF represent the trend of changes in corneal biomechanics and thickness during the early postoperative months.

Outcomes of Cataract Surgery at a Referral Center.

PURPOSE: To report the outcomes of cataract surgery at a large referral eye hospital and to identify factors associated with less than excellent visual outcomes. METHODS: Hospital records of patients, who had undergone age-related cataract extraction (1,285 procedures) within a two-year period were sampled randomly for 353 patients (405 eyes) and baseline characteristics were recorded. Up to three causes of visual loss (contributory reasons) were considered and the principal cause of "less than excellent outcome," i.e., best spectacle corrected visual acuity (BSCVA) <20/25 was defined as the primary reason. RESULTS: Mean age of the participants was 68.6 years, and 50.7% of enrolled subjects were female. Phacoemulsification had been performed in 92.1% of cases. Out of 405 eyes, 54%, 78%, and 97% achieved BSCVA of ≥20/25, ≥20/40, and ≥20/200, respectively. Poor visual outcomes were significantly associated with older age (OR: 4.55 for age >70 years), female gender (OR: 4.64), ocular comorbidities (OR: 7.68), surgically challenging eyes (OR: 7.33), long and short eyes (versus eyes with normal axial length, OR: 3.24), and being operated on by a novice surgeon (OR: 2.41). The leading contributory reasons for unfavorable outcome, in descending order were maculopathy (17%), posterior capsule opacification (PCO, 11.8%), corneal opacity (5.7%), and degenerative myopia (5.4%). CONCLUSION: Maculopathy, PCO, corneal opacity, degenerative myopia and ARMD may contribute to unfavorable outcomes in cataract surgery.

Effects of mitomycin-C on tear film, corneal biomechanics, and surface irregularity in mild to moderate myopic surface ablation: preliminary results.

PURPOSE: To assess the effect of mitomycin-C (MMC) on the tear film, corneal biomechanics, and surface irregularity in surface ablation (photorefractive keratectomy [PRK]) for low to moderate myopia. SETTING: Refractive Surgery Unit, Farabi Eye Hospital, Tehran, Iran. DESIGN: Double-masked randomized clinical trial. METHODS: In patients with spherical equivalent myopia of -0.75 to -3.87 diopters (D) and astigmatism up to -1.75 D, the first eye was randomly assigned to the application of MMC 0.02% or a balanced salt solution for 15 seconds. The fellow eye received the alternate in a masked fashion after excimer photoablation. RESULTS: The study enrolled 60 patients. In fellow eyes, the changes in the tear-film index were comparable 1 month and 6 months postoperatively. There was no significant difference in changes in total higher-order aberrations, spherical aberration, coma, or Q values (Pentacam HR) between fellow eyes at 1 month and 6 months. There was a trend toward a higher asymmetry index at 1 month; however, a statistically significant drop was observed at 6 months in the MMC group (P<.01). It was hypothesized that stromal remodeling was delayed, but better, in MMC-treated eyes. No haze was recorded at 6 months in either group. CONCLUSION: Use of MMC in PRK did not appear to contribute significantly to surface irregularity, transient tear-film dysfunction, or biomechanical weakening of the cornea compared with PRK without MMC. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

The role of demographic characteristics in the outcomes of cataract surgery and gender roles in the uptake of postoperative eye care: a hospital-based study.

PURPOSE: To explore the effect of demographic characteristics on the outcomes of cataract surgery in terms of visual acuity and patient satisfaction, and gender role in the uptake of postoperative care. METHODS: Comprehensive ocular examinations were performed on 478 subjects (558 eyes) over the age of 50 years who underwent surgery for age-related cataract at the largest eye hospital in Iran. Demographic characteristics were obtained and surgical records were reviewed. RESULTS: Male subjects had significantly better outcomes in terms of uncorrected visual acuity (UCVA) and best spectacle-corrected visual acuity (BSCVA) (mean difference 0.12 and 0.13 logMAR; p = 0.004 and p < 0.001, respectively). Women were significantly less satisfied than men (73.2% vs. 83.6%; p = 0.011). Postoperative UCVA and BSCVA were better in patients with higher levels of education (both p < 0.001). Age had an inverse association with UCVA (p = 0.004) and BSCVA (p < 0.001). Women were twice as likely to need capsulotomy (p = 0.002). Men's uptake of postoperative refractive care was 4-fold that of women's (31% vs. 7%). In multivariable analyses, age, sex, education, presence of ocular comorbidity and need for capsulotomy, spectacle prescription and other care were associated with postoperative UCVA (all p < 0.05; adjusted R(2) = 0.256). CONCLUSION: Female patients were shown to be at a clear disadvantage in cataract surgery; outcomes of the procedure and postoperative care were both poorer. Older age, lower level of education, ocular comorbidity and unmet postoperative need were also associated with a poorer outcome.

Using artificial intelligence to predict the risk for posterior capsule opacification after phacoemulsification.

PURPOSE: To apply artificial intelligence models to predict the occurrence of posterior capsule opacification (PCO) after phacoemulsification. SETTING: Farabi Eye Hospital, Tehran, Iran. DESIGN: Clinical-based cross-sectional study. METHODS: The posterior capsule status of eyes operated on for age-related cataract and the need for laser capsulotomy were determined. After a literature review, data polishing, and expert consultation, 10 input variables were selected. The QUEST algorithm was used to develop a decision tree. Three back-propagation artificial neural networks were constructed with 4, 20, and 40 neurons in 2 hidden layers and trained with the same transfer functions (log-sigmoid and linear transfer) and training protocol with randomly selected eyes. They were then tested on the remaining eyes and the networks compared for their performance. Performance indices were used to compare resultant models with the results of logistic regression analysis. RESULTS: The models were trained using 282 randomly selected eyes and then tested using 70 eyes. Laser capsulotomy for clinically significant PCO was indicated or had been performed 2 years postoperatively in 40 eyes. A sample decision tree was produced with accuracy of 50% (likelihood ratio 0.8). The best artificial neural network, which showed 87% accuracy and a positive likelihood ratio of 8, was achieved with 40 neurons. The area under the receiver-operating-characteristic curve was 0.71. In comparison, logistic regression reached accuracy of 80%; however, the likelihood ratio was not measurable because the sensitivity was zero. CONCLUSION: A prototype artificial neural network was developed that predicted posterior capsule status (requiring capsulotomy) with reasonable accuracy. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.