Association between metformin use with circumpapillary retinal nerve fibre layer thickness and capillary vessel density in glaucoma.

BACKGROUND/AIMS: To investigate the association between use of metformin and circumpapillary retinal nerve fibre layer (cpRNFL) thickness, as well as whole image capillary density (wiCD), in patients with glaucoma. METHODS: This cross-sectional study included patients with glaucoma suspect or primary open-angle glaucoma (POAG) underwent optical coherence tomography angiography imaging. Use and duration of antidiabetic medications were assessed at the time of imaging. Multivariable linear mixed-effect modelling was used to estimate the effect of diabetes medication on wiCD and cpRNFL while controlling for covariates including age, race, body mass index, diagnosis, 24-2 visual field mean deviation, and intraocular pressure, average signal strength index as well as any variables that showed a p <0.1 in the univariable analysis. RESULTS: A total of 577 eyes (330 POAG and 247 glaucoma suspect) of 346 patients were included. Sixty-five patients (23%) had diabetes, of whom 55 (78.5%) used metformin, and 17 (26.2%) used insulin. After adjusting for covariates, the association between metformin use and wiCD (1.56 (95% CI 0.40 to 2.71); p=0.008), duration of metformin use and wiCD (0.12 (95% CI 0.02 to 0.22) per 1 year longer; p=0.037), and metformin use and cpRNFL thickness (5.17 (95% CI 1.24 to 9.10) µm; p=0.010) had statistically significant associations in each model. CONCLUSIONS: Metformin use was associated with higher wiCD and thicker cpRNFL. These findings indicate a potential association, underscoring the need for longitudinal studies to determine if metformin plays a role in the retinal conditions of patients with glaucoma. TRIAL REGISTRATION NUMBER: NCT00221897.

Latanoprostene Bunod 0.024% in Patients with Open-Angle Glaucoma Switched from Prior Pharmacotherapy: A Retrospective Chart Review.

Introduction: Latanoprostene bunod 0.024% (LBN, Vyzulta®) is a nitric oxide-donating prostaglandin analog (PGA). We investigated the real-world efficacy and safety of LBN in patients with open-angle glaucoma (OAG) or ocular hypertension (OHT) who switched their existing intraocular pressure (IOP)-lowering treatment(s) to LBN. Methods: This non-interventional, multicenter (United States), retrospective chart review included patients aged ≥18 years with OHT and/or mild-to-moderate OAG diagnoses taking 1-2 IOP-lowering treatments at the time of switch to LBN (index visit). Chart-extracted data included demographics, diagnoses, IOP and ocular assessments, other IOP-lowering treatments, adverse events (AEs), and reasons for discontinuation. The main study outcome was IOP change from the index visit to each of the next 2 chart-recorded follow-up visits. Analysis groups included the overall dataset and 2 subgroups of patients switched from PGA therapy to LBN: "PGA-all" subgroup [all patients previously on a PGA with/without another IOP-lowering product] and "PGA-monotherapy" subgroup [patients previously on a PGA alone]). Additional ocular outcomes (eg, visual acuity) were examined, if available. Results: The overall dataset included 49 patients (46 had OAD alone, 2 had OHT alone, and 1 had both). The PGA-all subgroup and PGA-monotherapy subgroups had 41 and 32 patients, respectively. Switching to LBN led to a ~25% IOP reduction from the index visit to Visit 1 that was sustained at Visit 2. IOP findings in the PGA-all and PGA-monotherapy subgroups were consistent with the overall dataset. No meaningful changes in other ocular outcomes were found. Of 14 ocular AEs, 3 were recorded as such (mild in severity, considered unrelated to treatment), and 11 were identified through review of interval ocular histories (no severity/relatedness information); none led to discontinuation. Conclusion: In this short-term retrospective chart review of mild-to-moderate OAG/OHT, switching prior IOP-lowering therapy to LBN produced an additional ~25% IOP reduction and appeared to be well tolerated.

Reproducibility of minimum rim width and retinal nerve fibre layer thickness using the Anatomic Positioning System in glaucoma patients.

OBJECTIVE: To determine the test-retest repeatability of minimum rim width and retinal nerve fibre layer thickness measurements obtained by spectral-domain optical coherence tomography using the Anatomic Positioning System protocol in glaucoma patients and controls. Also, to assess the ability of the minimum rim width and retinal nerve fibre layer thickness to diagnose glaucoma in 2 circular peripapillary locations. METHODS: Spectral domain optical coherence tomography scans of the optic nerve head were obtained twice during the same visit using the Anatomic Positioning System eye-tracking protocol. The minimum rim width and retinal nerve fibre layer thickness were measured at 3 circular diameters (3.5 mm, 4.1 mm, and 4.7 mm). Intraclass correlation coefficients and area under the receiver operating characteristic were calculated for these parameters. RESULTS: A total of 36 glaucomatous eyes and 59 control eyes were included in the analysis. The intraclass correlation coefficients of minimum rim width and retinal nerve fibre layer thickness global measurement for 3.5 mm and 4.1 mm circles ranged between 0.98 and 1.00 and for 4.7 mm circle was between 0.76 and 1.00. The minimum rim width had an area under the receiver operating characteristic of 0.97, while the retinal nerve fibre layer thickness measurements had an area under the receiver operating characteristic of 0.95, 0.95, and 0.96 for the 3.5 mm, 4.1 mm, and 4.7 mm circles, respectively. CONCLUSIONS: The minimum rim width and retinal nerve fibre layer thickness measurements using the Anatomic Positioning System protocol had overall excellent reproducibility and diagnostic performance. Using this protocol and the novel minimum rim width parameter may be useful in more accurate diagnosis and follow-up of patients with glaucoma.

Philadelphia Telemedicine Glaucoma Detection and Follow-up Study: confirmation between eye screening and comprehensive eye examination diagnoses.

AIMS: To evaluate agreement between ocular findings of a telemedicine eye screening (visit 1) with diagnoses of a comprehensive eye examination (visit 2). METHODS: A primary care practice (PCP)-based telemedicine screening programme incorporating fundus photography, intraocular pressure (IOP) and clinical information was conducted. Eligible individuals were African American, Hispanic/Latino or Asian over the age of 40; Caucasian individuals over age 65; and adults of any ethnicity over age 40 with a family history of glaucoma or diabetes. Participants with abnormal images or elevated IOP were invited back for a complete eye examination. Both visit 1 and visit 2 were conducted at participants' local PCP. Ocular findings at visit 1 and eye examination diagnoses at visit 2 are presented, including a cost analysis. RESULTS: Of 906 participants who attended visit 1, 536 were invited to visit 2 due to ocular findings or unreadable images. Among the 347 (64.9%) who attended visit 2, 280 (80.7%) were diagnosed with at least one ocular condition. Participants were predominately women (59.9%) and African American (65.6%), with a mean age (±SD) of 60.6±11.0 years. A high diagnostic confirmation rate (86.0%) was found between visit 1 and visit 2 for any ocular finding. Of 183 with suspicious nerves at visit 1, 143 (78.1%) were diagnosed as glaucoma or glaucoma suspects at visit 2. CONCLUSIONS: This screening model may be adapted and scaled nationally and internationally. Referral to an ophthalmologist is warranted if abnormal or unreadable fundus images are detected or IOP is >21 mm Hg. TRIAL REGISTRATION NUMBER: NCT02390245.

Is primary open-angle glaucoma an ocular manifestation of systemic disease?

Primary open-angle glaucoma is currently characterized by a pattern of progressive retinal ganglion cell loss that stems from a complex underlying pathophysiology that remains poorly elucidated. The roles of blood flow and intraocular pressure (IOP) in glaucoma pathogenesis have been extensively studied. Further, it has been established that lowering IOP can slow the progression of glaucoma. In addition, a number of influential factors have emerged and gained momentum over the years. Increasing evidence implicates the contributions of low cerebrospinal fluid pressure, autoimmunity, neurodegeneration, and impaired autoregulation towards glaucoma pathophysiology. We aggregate and explore these different camps of thought that have garnered attention over the last few decades, and, in doing so, aim to challenge the long-standing view of glaucoma as a primary disease of the eye. A shift in our perspective towards understanding glaucoma as an ocular manifestation of systemic dysregulation may lead ultimately to better clinical management of the disease.

Validation of the structure-function correlation report from the heidelberg edge perimeter and spectral-domain optical coherence tomography.

PURPOSE: To compare the diagnostic assessment of glaucoma specialists with an automated structure-function correlation report combining visual field (VF) and spectral-domain optical coherence tomography (SD-OCT) imagining in subjects with glaucoma. METHODS: This prospective, cross-sectional study was conducted at Wills Eye Hospital, Philadelphia, PA, USA. Subjects with glaucoma received ophthalmic examination, VF testing, and SD-OCT imaging. An automated report was generated describing structure-function correlations between the two structural elements [retinal nerve fiber layer (RNFL) and Bruch's membrane opening-minimum rim width (MRW)] and VF sectors. Three glaucoma specialists masked to the automated report and to each other identified clinically significant structure-function correlations between the VF and SD-OCT reports. Raw agreement and chance-corrected agreement (kappa statistics) between the automated report and the clinical assessments were compared. RESULTS: A total of 53 eyes from 45 subjects with glaucoma were included in this study. The overall agreement between the automated report and clinical assessment comparing MRW and VF was good at 74.8% with a kappa of 0.62 (95% CI 0.55-0.69). Agreements for the six different MRW sections were moderate to good with kappa values ranging from 0.54 to 0.69. For mean RNFL thickness and VF comparisons, agreement between the automated report and clinical assessment was 75.4% with a kappa of 0.62 (95% CI 0.54-0.70). For different RNFL sectors, kappa values ranged from 0.47 (moderate agreement) to 0.80 (good agreement). CONCLUSIONS: This study suggests that the automated structure-function report combining results from the SD-OCT and the HEP may assist in the evaluation and management of glaucoma.

Philadelphia Telemedicine Glaucoma Detection and Follow-up Study: Analysis of Unreadable Fundus Images.

PURPOSE: The purpose of this study was to ascertain determinants of unreadable fundus images for participants enrolled in the Philadelphia Telemedicine Glaucoma Detection and Follow-up Study. METHODS: Individuals were screened for glaucoma at 7 primary care practices and 4 Federally Qualified Health Centers using telemedicine. Screening (visit 1) included fundus photography, assessing family history of glaucoma, and intraocular pressure (IOP) measurements. Participants with an unreadable image in at least one eye were deemed unreadable and invited to return for a confirmatory eye examination (visit 2). RESULTS: A total of 906 participants completed the visit 1 eye screening and 17.1% (n=155/906) were "unreadable." In the multivariable logistic regression analysis, older age, male sex, smoking, and worse visual acuity were significantly associated with an unreadable fundus image finding at the eye screening (P<0.05). Of the 89 participants who were invited for the confirmatory eye examination solely for unreadable images and attended visit 2, 58 (65.2%) were diagnosed with at least one ocular pathology. The most frequent diagnoses were cataracts (n=71; 15 visually significant, 56 nonvisually significant), glaucoma suspects (n=27), and anatomical narrow angle (n=10). CONCLUSIONS: Understanding the causes of unreadable fundus images will foster improvements in telemedicine techniques to optimize the predictive accuracy, efficiency, and cost in ophthalmology. A high proportion of participants with unreadable images (65.2%) in our study were diagnosed with some ocular pathology, indicating that the finding of an unreadable fundus image warrants a referral for a comprehensive follow-up eye examination.

Depression and quality of life in a community-based glaucoma-screening project.

OBJECTIVE: To identify the prevalence and risk factors of depression among individuals given a glaucoma-related diagnosis at a screening program. DESIGN: Cross-sectional community-based in a university hospital. PARTICIPANTS: Volunteers from a community glaucoma-screening program. METHODS: After collecting sociodemographic information, participants were administered the Geriatric Depression Scale-15 (GDS-15) and the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25). RESULTS: Participants were predominantly African American (73.5%), older than 65 years (65.7%), single (75.4%), and female (66.8%). Among 268 participants, 89 were diagnosed with glaucoma and 179 as glaucoma suspects. The frequency of depression among the glaucoma and glaucoma suspect participants was 18% and 16.2%, respectively. The mean GDS-15 score was 2.4 ± 2.7 with no difference between glaucoma and glaucoma suspect groups, p = 0.654. The mean VFQ-25 score was 78.6 ± 15.9 and was lower in glaucoma (74.7 ± 19.7) than glaucoma suspect participants (80.4 ± 13.6), p = 0.003. Risk factors for depression included difficulties with paying expenses (p = 0.017), Asian race (p < 0.001), and poorer scores on the VFQ-25 subscales of "General Health" (p < 0.001), "Distance Activities" (p = 0.024), and "Dependency" (p = 0.001). CONCLUSIONS: Prevalence of depression in those diagnosed with glaucoma or glaucoma suspect was higher than previous estimates of the general population. Glaucoma-screening programs might benefit from including depression-screening protocols along with referral services or low-cost treatments of depression.

Visual Field Changes in Professional Wind versus Non-wind Musical Instrument Players in the Philadelphia Orchestra.

PURPOSE: We compare the prevalence of glaucoma in professional wind versus non-wind instrument players in the Philadelphia Orchestra. Visual field changes in individuals with glaucoma and glaucoma suspects were evaluated, and the results were correlated with cumulative practice time. METHODS: In this cross-sectional, observational study, fifty-one Philadelphia Orchestra musicians were enrolled and categorized as wind or non-wind instrument players. All study participants underwent screening fundus photography. Participants with optic discs suspicious for glaucoma underwent further evaluation, including standard automated visual field perimetry and a comprehensive eye examination by a glaucoma specialist. RESULTS: Of the 51 musicians enrolled, 9 of the 21 wind instrument players (43%) and 8 of the 30 non-wind instrument players (27%) were suspected of developing glaucoma in at least one eye (P = 0.25), with examinations performed on 12 of the 17 returning musicians (71%) for further confirmation. Wind instrument players exhibited significantly higher Octopus visual field mean defect scores (1.08 ± 1.5 dB) than non-wind instrument players (-0.43 ± 0.7 dB; P < 0.001). There was a significant association between cumulative hours playing wind instruments and visual field mean defect (P < 0.001). CONCLUSION: Among members of the Philadelphia Orchestra, the difference in prevalence of glaucoma suspicious optic discs between wind and non-wind instrument players was not significant. The clinical significance of the greater visual field mean defect found in wind instrument players, and the association between the degree of visual field mean defect and the cumulative practice-time of playing wind instruments, needs further investigation.

Clinical Efficacy and Safety Profile of Micropulse Transscleral Cyclophotocoagulation in Refractory Glaucoma.

PURPOSE: To investigate the clinical efficacy and safety profile of micropulse transscleral cyclophotocoagulation (MP-CPC) in patients with refractory glaucoma. MATERIALS AND METHODS: Retrospective case series of 79 consecutive patients who underwent MP-CPC at the Wills Eye Hospital from March 23, 2014 to June 23, 2016 and who had at least 3 months of follow-up. Treatment success was defined as an intraocular pressure (IOP) of 6 to 21 mm Hg or a reduction of IOP by 20%. Failure was defined as an inability to meet the criteria for success, need for retreatment >3 times, or need for incisional glaucoma surgery. RESULTS: Patients had a mean follow-up time of 7.8±4.5 months. The mean IOP before MP-CPC was 31.9±10.2 mm Hg. The IOP was reduced by an average of 51% at the last follow-up and the mean number of IOP lowering medications was reduced from 2.3 at baseline to 1.5 at last follow-up. Treatment success rates were 75% at 3 months, 66% at 6 months, and 67% at last follow-up. Complications of MP-CPC included 7 patients with hypotony (8.8%), 21 patients with prolonged anterior chamber inflammation (1+ cell or flare for >3 mo, 26%), 13 patients with loss of ≥2 lines of best-corrected visual acuity at 3 months (17%), 4 patients with macular edema (5%), 2 patients with corneal edema and 2 patients with phthisis. CONCLUSIONS: MP-CPC is an effective treatment for patients with refractory glaucoma. Shorter treatment times with more frequent repeat treatments, if necessary, should be considered given the incidence of significant vision loss in this study.

Evolution of Cyclophotocoagulation.

Cyclodestructive techniques have been a treatment option for refractory glaucoma since its first use in the 1930s. Over the past nine decades, cyclodestruction has advanced from the initial cyclodiathermy to micropulse transscleral cyclophotocoagulation (MP-TSCPC) which is the current treatment available. Complications associated with cyclodestruction including pain, hyphema, vision loss, hypotony and phthisis have led ophthalmologists to shy away from these techniques when other glaucoma treatment options are available. Recent studies have shown encouraging clinical results with fewer complications following cyclophotocoagulation, contributing greatly to the current increase in the use of cyclophotocoagulation as primary treatment for glaucoma. We performed our literature search on Google Scholar Database, Pubmed, Web of Sciences and Cochrane Library databases published prior to September 2017 using keywords relevant to cyclodestruction, cyclophotocoagulation and treatment of refractory glaucoma.

Factors Associated with Patient Satisfaction in an Outpatient Glaucoma Population.

PURPOSE: To determine what metrics might impact satisfaction survey responses. METHODS: A 37-question survey was administered to 249 participants. Responses were correlated to demographics, clinical factors, weather conditions, and examination timing. RESULTS: Sample consists of 55.4% female and 73.9% white, and mean age was 65.1 years. Participants were assigned to: completely satisfied (77.9%) or not completely satisfied (22.1%) groups based on their rating of glaucoma specialist on a scale of 1-10, while 10 considered "completely satisfied" and less than 10 "not completely satisfied." Complete satisfaction was associated with ability to schedule appointments early, phone calls answered/returned same day, shorter perceived wait time, and better communication skills of ophthalmologist (p < 0.05). Completely satisfied participants reported their ophthalmologist spent enough time with them, listened carefully, and communicated in an understandable way (p < 0.05). CONCLUSIONS: The majority of factors found to be associated with patient satisfaction were related to characteristics of the ophthalmologists and their office.

Trypan Blue for the Assessment of Filtering Bleb Function During Cataract Surgery.

PURPOSE: Phacoemulsification has been cited as a possible cause of bleb failure in eyes with prior trabeculectomy. No method has been developed to directly evaluate the risk of bleb failure after phacoemulsification. We investigate the use of trypan blue during cataract surgery in the setting of a preexisting trabeculectomy to evaluate the functional status of the bleb and predict postoperative bleb function. MATERIALS AND METHODS: In total, 14 patients contributing 1 eye each with a history of prior trabeculectomy with mitomycin C undergoing phacoemulsification with intraocular lens implantation were enrolled in this prospective, nonrandomized clinical trial. At the time of phacoemulsification, trypan blue was instilled into the anterior chamber before capsulorhexis creation. Staining of the bleb was grouped as being mild or diffuse using intraoperative photographs. These eyes were followed for 1 year postoperatively and evaluated for intraocular pressure (IOP) control. RESULTS: The change in IOP was not significantly different between the 2 groups (P=0.14). A trend towards greater need for IOP-lowering medications was noted (P<0.10) in eyes with mild bleb staining. No statistically significant difference in rates of decreased bleb function was noted at 1-year follow-up after phacoemulsification. CONCLUSION: The intensity of bleb staining with trypan blue during phacoemulsification is not associated with changes in IOP postoperatively. A trend towards decreased need for IOP-lowering medications was noted in eyes with diffuse bleb staining at 1 year after cataract surgery.

The Effects of Latanoprost With Benzalkonium Chloride Versus Travoprost With SofZia on the Ocular Surface.

PURPOSE: To assess ocular surface changes in participants using latanoprost with benzalkonium chloride (Xalatan) and travoprost with SofZia (Travatan Z). METHODS: In this prospective, open-label, nonrandomized cohort study, participants were classified into two groups: group 1 (n=28) naive to glaucoma therapy, group 2 (n=27) on previous Xalatan monotherapy in both eyes. Both groups started (or continued) Xalatan in the right eye and Travatan Z in the left eye. Baseline, 1-, and 2-month measurements of tear breakup time (TBUT), corneal staining score, conjunctival staining score, conjunctival hyperemia score, tear production, and intraocular pressure were obtained. The Ocular Surface Disease Index questionnaire measured participants' comfort and dryness symptoms. Medication preference was recorded. RESULTS: Data were collected from 55 participants. Tear breakup time at baseline and 1-month follow-up in group 1 was significantly longer than that of group 2 (P=0.005). At 2 months, there was no significant difference in TBUT between the two groups (P=0.779). Tear production in group 1 at all three time points was significantly higher than group 2 (P<0.05). Conjunctival staining score at 2 months in group 1 was significantly higher than group 2 (P=0.031). There was no significant difference in other parameters between the groups at any other time point. No significant difference in any parameter was found between Xalatan and Travatan Z (intragroup comparison). CONCLUSIONS: Significant differences in ocular surface characteristics were detected between groups, but no significant difference was detected between participants treated with Xalatan and Travatan Z.

Surgical Outcomes of Gonioscopy-assisted Transluminal Trabeculotomy (GATT) in Patients With Open-angle Glaucoma.

PURPOSE: To evaluate the efficacy and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in patients with open-angle glaucoma. PARTICIPANTS AND METHODS: A retrospective chart review of adult patients who underwent GATT due to inadequately controlled intraocular pressure (IOP) or intolerance to medication. Main outcome measures were success rate, IOP, and number of glaucoma medications. Success was defined as IOP reduction >20% from baseline or IOP between 5 to 21 mm Hg, and no need for further glaucoma surgery. When success criteria were not met for any postoperative visit >3 months after surgery, failure was determined. RESULTS: In total, 66 patients, average age 62.9±14.9 years (50.8% female) were included in the analysis. Average follow-up was 11.9 months (range, 3 to 30 mo) and overall success rate was 63.0%. Mean IOP was 26.1±9.9 mm Hg preoperatively and 14.6±4.7 mm Hg at 12 months (44% IOP decrease; P<0.001). Mean number of medications decreased from 3.1±1.1 preoperatively to 1.2±0.9 at 12 months (P<0.001). No significant differences between patients with primary open-angle glaucoma and other types of glaucoma were found.The rate of hyphema at 1 week and 1 month postoperatively was 38% and 6%, respectively. Overall GATT success rate among white and black patients was 69% and 42%, respectively, which was statistically significant (P<0.05). CONCLUSIONS: The future of GATT as a minimally invasive glaucoma surgery in adults seems promising. This position is supported by its low rate of long-term complications and the conjunctiva-sparing nature of the surgery.

The relationship between contrast sensitivity and retinal nerve fiber layer thickness in patients with glaucoma.

PURPOSE: To evaluate the correlation between contrast sensitivity (CS) and retinal nerve fiber layer (RNFL) in different areas of vision. METHODS: This report is a sub-analysis of a prospective, observational cohort study investigating changes in performance-based assessment, vision-related quality of life, and clinical measures in patients with moderate to advanced glaucoma. The study included 161 participants with at least a 2-year history of glaucoma who underwent annual testing for 4 years. Contrast sensitivity was measured using the Spaeth/Richman contrast sensitivity (SPARCS) test, while RNFL thickness (RNFLT) was measured using Cirrus optical coherence tomography (OCT). Statistical analyses were performed to determine correlations between CS and RNFLT; the correlations were calculated for each annual visit, totaling four correlation coefficients for each patient over the course of 4 years. RESULTS: The SPARCS score in the left upper area of vision correlated the most strongly with the RNFLT of the inferior quadrant for both eyes at each annual visit, specifically in the seven o'clock sector for the left eye and the six o'clock sector for the right eye (p < 0.05). There were no discernible trends for the correlations between the other areas of CS and RNFL quadrants or clock hours over the 4 years of the study. Linear regression between the SPARCS total score and average RNFLT showed a significant direct correlation at each visit (p < 0.01). CONCLUSIONS: Contrast sensitivity in the left upper area of vision for both eyes correlated most strongly with the thickness of the inferior quadrant of the RNFL. These fibers project to the temporal portion of the right occipital lobe, implying a potential center for contrast perception in this area. The longitudinal nature of the study suggests that CS may be a predictive tool for changes in RNFL in patients with glaucoma. Despite this finding, retinal damage and its relationship to CS was diffuse. In addition, SPARCS was shown to predict RNFLT. Further research is warranted to understand how CS can be used as a tool in the clinical setting.

Efficacy of Wavefront-guided Photorefractive Keratectomy with Iris Registration for Management of Moderate to High Astigmatism by Advanced Personalized Treatment Nomogram.

PURPOSE: To evaluate the efficacy of photorefractive keratectomy (PRK) using the advanced personalized treatment (APT) nomogram for correction of moderate to high astigmatism. METHODS: This prospective interventional case series included 60 consecutive eyes of 30 patients undergoing wavefront-guided PRK (Zyoptix 217 Z100 excimer laser, Bausch & Lomb, Munich, Germany) using the APT nomogram and iris registration for myopic astigmatism. Mitomycin-C was applied intraoperatively in all eyes. Ophthalmic examination was performed preoperatively and 1, 3 and 6 months postoperatively. RESULTS: Preoperatively, mean sphere was -1.68 ± 2.08 diopters (D), mean refractive astigmatism was -3.04 ± 1.05 D and mean spherical equivalent (SE) was -3.12 ± 1.77 D. Six months postoperatively, mean sphere was + 0.60 ± 0.64 D (P < 0.005), mean cylinder was -0.43 ± 0.46 D (P < 0.005) and mean SE was + 0.28 ± 0.48 D (P < 0.005). Hyperopic overcorrection (≥ +1.0 D) occurred in 3 (5%) eyes. Postoperatively, root mean square (RMS) of higher order aberrations (HOAs) was significantly increased (P = 0.041). RMS of spherical aberration (Z [4, 0]) showed no significant change after surgery (P = 0.972). CONCLUSION: Considering the acceptable residual refractive error, low rate of hyperopic overcorrection, acceptable uncorrected visual acuity, and low risk of postoperative corneal haze, PRK using the APT nomogram with iris registration and mitomycin-C use is a safe and effective modality for treatment of moderate to high astigmatism.