Preoperative Retinal Nerve Fiber Layer Research Articles

Refining Glaucoma Diagnosis and Treatment in Cataract Surgery Candidates: The Contribution of Preoperative OCT RNFL.

To evaluate the clinical significance of preoperative spectral domain optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) thickness in identifying glaucoma and better managing patients scheduled for routine cataract surgery. Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel.Design: retrospective cohort study. Consecutive patients scheduled for cataract surgery were enrolled from February 2022 to August 2022. Participants underwent routine OCT RNFL studies which were evaluated by a glaucoma specialist. Findings were compared with those of preoperative fundus biomicroscopic examinations conducted by the referring ophthalmologist. The main outcomes were the incidence of newly detected glaucoma based upon OCT RNFL findings and the consequent changes in patient management. In total, 486 patients met the inclusion criteria, of whom 112 (23%) had abnormal RNFL. Thirty-one patients (6.4%) had abnormal OCT RNFL findings attributed to comorbidities other than glaucoma, and 81 patients (16.7%) were suspected to have glaucoma based upon their OCT RNFL findings, from which 44 patients (9%) were newly diagnosed with glaucoma or as glaucoma suspects, resulting in management modifications that included routine glaucoma follow-up (25 patients, 5.1%), initiation of intraocular pressure-lowering treatment (12 patients, 2.5%), and conversion to combined cataract-glaucoma surgery (7 patients, 1.4%). OCT RNFL for cataract surgery candidates proved valuable in detecting glaucoma that had not been revealed by standard fundus biomicroscopic examination. The additional information provided by OCT RNFL can potentially enhance patient management and optimize outcomes.

OPTICAL COHERENCE TOMOGRAPHY PREDICTS VISUAL RECOVERY OF PATIENTS WITH PITUITARY ADENOMA FOLLOWING SURGERY IN DR KARIADI HOSPITAL,SEMARANG

Introduction and Objective: The characteristics, symptoms, and clinical manifestations of pituitary adenoma in Indonesia have not been widely studied. In 26 patients undergoing pituitary surgery at Dr. Kariadi Hospital, we compared visual acuity pre-operative and post-operative from normal and thin optical coherence tomography (OCT) of the retinal nerve fiber layer (RNFL) and ganglion cell layer-internal plexiform layer (GCL-IPL).
 Method: A retrospective study of the medical record from January 2020 to December 2022 was done. 21 of the 26 patients had surgery by the transsphenoidal route and the rest by craniotomy. All patients had macroadenoma (tumor size >1cm) and were histologically confirmed. Visual acuity before and after surgery was evaluated along with the patient’s OCT value.
 Result: The thinner pre-operative RNFL thickness was associated with worse visual acuity (VA). Patients with normal RNFL had a median VA of 20/200 while those with thin RNFL had to count their fingers (CF). The patients with normal pre-operative RNFL had a significant improvement in median VA after surgery, from 20/200 to 20/32 (p=0.022), whereas the patients with thin RNFL did not improve (CF to CF, p=0.026). The patients with normal pre-operative GCL-IPL had non-significant improvement in median VA after surgery from CF to 20/20 (p=0.505), also the patients with thin GCL-IPL from CF to 20/200 (p=0.151).
 Conclusion: The visual recovery after pituitary adenoma surgery is likely to be predicted by pre-operative OCT RNFL. Patients with normal RNFL thickness show an increased tendency in visual recovery after surgery.
 Keywords: Optical coherence tomography , visual acuity, pituitary adenoma

Factors Affecting Post-Cataract OCT Parameters in Open-Angle and Angle-Closure Glaucoma Eyes: Optic Disc Head Analysis

Purpose: The aim of this study was to investigate whether there are differences in the effects of cataract surgery based on the type of glaucoma and changes in the retinal nerve fiber layer (RNFL) thickness and Bruch's membrane opening-minimum rim width (BMO-MRW) thickness around the optic nerve and macula in patients with glaucoma. Furthermore, the factors influencing these effects were explored.Methods: 68 patients with glaucoma were enrolled, and changes in RNFL thickness and BMO-MRW before and after cataract surgery were measured using SD-OCT. The patients were divided into angle-closure and open-angle glaucoma groups and values before and after cataract surgery were analyzed.Results: The male-female ratio was 26:42, with an average age of 71.72 years at the time of surgery. There were 35 eyes with open-angle glaucoma and 33 eyes with angle-closure glaucoma. After cataract surgery, both RNFL and BMO-MRW values significantly increased. In the angle-closure glaucoma group, preoperative visual acuity was significantly better and RNFL image Q was significantly higher before cataract surgery. In a multivariate linear regression analysis, the factor influencing the increase in RNFL thickness was found to be the preoperative RNFL thickness in both the overall open angle glaucoma group and the angle closure glaucoma group. In other words, patients with thinner RNFL thickness before cataract surgery showed an increase in RNFL thickness after the surgery. In the angle closure glaucoma group, it was observed that worse preoperative visual acuity was associated with an increase in RNFL thickness after surgery. Conversely, no factors affecting BMO-MRW thickness were identified.Conclusions: The factors influencing the increase in RNFL thickness after cataract surgery were the preoperative RNFL thickness in open angle glaucoma group and the preoperative visual acuity in the angle closure glaucoma group.

Variability of Visual Recovery with Time in Epiretinal Membrane Surgery: A Predictive Analysis Based on Retinal Layer OCT Thickness Changes.

To correlate postoperative optical coherence tomography (OCT) thickness changes of each retinal layer with different patterns of visual recovery after idiopathic epiretinal membrane (ERM) surgery in a cohort of patients showing no known risk factors for poor visual recovery at preoperative imaging. Best corrected visual acuity (BCVA) and OCT images were acquired preoperatively and 1 month, 3 months and 6 months postoperatively. Patients were divided into four groups according to postoperative BCVA improvement: improvement < 15 ETDRS letters (GROUP 1), immediate improvement of BCVA without further improvements at later follow-ups (GROUP 2), immediate improvement of BCVA with further improvements at later follow-ups (GROUP 3) and delayed improvement of BCVA (GROUP 4). Eighty-five patients were included. GROUP1 was the only one characterized by retinal nerve fiber layer (RNFL) thickness increase and ganglion cell layer/central macular thickness (GCL/CMT) ratio decrease at 1 month and outer nuclear layer (ONL) thickness decrease at 3 and 6 months. GROUP 2 was the only one showing a decrease in GCL/inner plexiform layer (GCL/IPL) ratio at 1 month. GROUP 3 and 4 showed higher preoperative RNFL thickness compared to the other, and GROUP 4 manifested a late increase in RNFL thickness at 6 months. Different patterns of VA recovery are associated with specific layer thickness changes. If further confirmed, this would help detect those cases characterized by poor or delayed visual recovery despite the absence of other known imaging risk factors.

CLINICAL IMPLICATION OF RETINAL NERVE FIBER LAYER SCHISIS AND MACULAR FLUORESCEIN LEAKAGE IN PRIMARY IDIOPATHIC EPIRETINAL MEMBRANE.

We evaluated the relationship between macular fluorescein leakage and retinal nerve fiber layer (RNFL) schisis and investigated the visual prognostic values after pars plana vitrectomy (PPV) and idiopathic epiretinal membrane removal. We analyzed the correlations between preoperative optical coherence tomography (OCT) parameters and macular leakage. The final best-corrected visual acuity and central macular thickness were compared according to the presence or absence of macular leakage and RNFL schisis. In 80 eyes with idiopathic epiretinal membrane treated with PPV and membrane peeling, preoperative macular leakage was associated with the presence of preoperative RNFL schisis and inner nuclear layer microcysts. Eyes with both macular leakage and RNFL schisis showed worse postoperative best-corrected visual acuity than those without both factors. In the presence of macular fluorescein leakage and RNFL schisis, postoperative best-corrected visual acuity is worse, and improvements in the central macular thickness are greater than those in the absence of both factors.

Predictors of Retinal Nerve Fiber Layer Parameters Following Scleral Buckling Surgery in Primary Rhegmatogenous Retinal Detachment.

Objective: This study aimed to examine predictors of retinal nerve fiber layer (RNFL) parameters following scleral buckling (SB) surgery for primary rhegmatogenous retinal detachment (RRD) and to determine the influence of the magnitude of change in qualitative and quantitative parameters on RNFL.Methods: In an observational prospective study, 40 subjects who underwent successful retinal reattachment with SB surgery done within one month of RRD were evaluated for the parameters of best-corrected visual acuity (BCVA), refractive error, intraocular pressure (IOP), axial length (AL), anterior chamber depth (ACD), angle opening distance (AOD 500 and AOD 750), trabecular iris surface area (TISA 500 and TISA 750), visual fields, and ganglion cell count (GCC) and RNFL before and three months after SB. We additionally noted qualitative factors like extent, location, and type of buckle; phakic status; and grade of proliferative vitreoretinopathy in the affected eye. The change in value of quantitative parameters was found. The influence of baseline values and magnitude of change of quantitative and qualitative parameters on average RNFL thickness and magnitude of change of RNFL thickness after SB was found.Results: Post-SB, average RNFL thickness reduced from 108.58±20.38 microns to 103.73±17.98 microns (p =0.042). The baseline temporal upper (TU), temporal lower (TL), and nasal lower (NL) RNFL thickness (p=0.01, p=0.02, p=0.01, respectively) and total deviation (TD) values of visual fields (p=0.01) correlated positively while baseline GCC gross loss of volume (p=0.01) correlated negatively with post-operative RNFL thickness. The TU, TL, and NL RNFL thickness (p=0.04, p=0.01, p=0.01, respectively) and average GCC (p=0.04) correlated negatively with the magnitude of change in RNFL. The magnitude of change in baseline parameters after surgery was correlated with the magnitude of change in average RNFL thickness. It was noticed that change in AL (p<0.01), TISA 500 (p=0.02), TISA 750 (p<0.01), GCC focal loss of volume (p=0.02), and temporal RNFL thickness (p<0.01) correlated positively while the change in refractive error correlated negatively (p=0.04). Except for the grade of proliferative vitreoretinopathy (PVR) (p=0.04), none of the qualitative parameters, including extent, type, and location of the buckle; and phakic status, had a significant association with post-operative average RNFL thickness or magnitude of its change.Conclusions: The predictors of average RNFL thickness following SB include AL; myopic shift; TISA; visual fields TD; average, TU, TL, and NL RNFL thickness; average GCC, gross and focal loss of volume; and grade of PVR. So an early surgery to prevent preoperative ganglion cell and RNFL loss and progression of PVR is recommended.

Long term predictive ability of preoperative retinal nerve fiber layer thickness in visual prognosis after chiasmal decompression surgery

ObjectiveTo investigate the relationship between preoperative retinal nerve fiber layer (RNFL) thickness and the recovery of visual field (VF) and visual acuity (VA) 1 year after surgery in chiasmal compression patients presenting with visual impairment. Patients and methodsTwenty-nine eyes of 16 patients with chiasmal compression and 14 eyes of 14 control subjects were enrolled. All patients undergoing chiasmal decompression surgery via a transsphenoidal approach were prospectively evaluated before and 1 year after surgery with best corrected visual acuity (BCVA, logMAR), mean deviation (MD) value with standard automated perimetry (SAP) and RNFL thickness with optical coherence tomography. Eyes with chiasmal compression were divided into two groups according to the mean preoperative RNFL thickness: ≥ 100 µm (Group 1) and < 100 µm (Group 2). The relationship between the mean preoperative RNFL thickness and visual prognosis parameters (VF, VA) was analyzed. ResultsThe mean preoperative RNFL thickness was 115.92 ± 8.97 µm, 84.0 ± 8.85 µm, and 114.21 ± 7.75 µm in Group 1 (n = 15 eyes), Group 2 (n = 14 eyes) and the control group (n = 14 eyes), respectively. The mean preoperative BCVA was 0.15 ± 0.3 in Group 1, and 0.41 ± 0.39 in Group 2. The mean BCVA increased to 0.03 ± 0.1 in Group 1 in the postoperative period but did not change in Group 2. MD value was − 6.10 ± 5.54 in the preoperative period and − 2.59 ± 2.23 in the postoperative period for Group 1 (p = 0.014), while it was − 18.97 ± 4.14 in the preoperative period and − 18.57 ± 4.51 in the postoperative period in Group 2 (p = 0.24). ConclusionsThis study suggests that lower mean preoperative RNFL thickness was associated with poorer long-term visual prognosis. Preoperative RNFL thickness measurements may be helpful in predicting the recovery of VF and VA after decompression surgery in patients with chiasmal lesion presenting with visual impairment.

Retinal nerve fiber layer thickness measured by optical coherence tomography predicts visual recovery after orbital decompression for dysthyroid optic neuropathy.

To determine the prognostic value of optical coherence tomography (OCT) measurement of the peripapillary retinal nerve fiber layer (RNFL) thickness in visual recovery after orbital decompression of patients with dysthyroid optic neuropathy (DON). A total of 52 eyes of 37 patients who underwent orbital decompression for DON between 2013 and 2019 were retrospectively reviewed. We examined peripapillary RNFL thickness, best-corrected visual acuity (BCVA), visual field (VF) for mean deviation (MD) and pattern standard deviation (PSD), and pattern-reversed visual evoked potential (PVEP) for P100 latency and amplitude before and after surgery. Black and white checkerboard square sizes of PVEP were 15 and 60 arcmin (arcminute and minute of angle). Changes in RNFL overall thickness and by quadrant and interocular differences were evaluated and studied regarding changes in BCVA, VF and PVEP. There was a significant improvement in BCVA, VF, and PVEP, whereas a dramatic reduction in RNFL thickness of all DON patients in global average, temporal, superior, and inferior quadrants (P = 0.005, P = 0.024, P = 0.016, and P = 0.001, respectively) after decompression surgery, except for nasal quadrant (P = 0.057). The preoperative RNFL thickness in each quadrant was negatively correlated with postoperative changes of BCVA and PSD and positively correlated with changes of MD and P100 amplitude at 60 arcmin (all P < 0.05). Except for temporal quadrant (P = 0.125), the preoperative RNFL thickness in other quadrants was positively correlated with postoperative changes of P100 amplitude at 15 arcmin (all P < 0.05). The nasal RNFL thickness was an excellent predictor for improvement in BCVA by 20/25 or better and in MD by 10dB or more after surgery, whose cutoff value was 73.50μm, while the inferior and superior RNFL thickness could act as a predictor for improvement in P100 amplitude by 5μV or more at 60 arcmin and at 15 arcmin, respectively, whose cutoff value was, respectively, 143.00μm and 130.50μm (all P < 0.05). RNFL thickness measured by OCT was correlated with visual function recovery after decompression surgery in patients with DON, which could also act as a predictor for better visual prognosis.

Functional Prognostic value of optical coherence tomography in optic chiasmal decompression: A preliminary study

To assess the predictive value for functional recovery of Ganglion Cell Complex Layer (GCC) and Retinal Nerve Fiber Layer (RNFL) measurements obtained by Optical Coherence Tomography (OCT) in patients undergoing chiasmal decompression and to define potential OCT thresholds for visual recovery. We measured preoperative GCC and RNFL thickness in patients with a sellar and/or perisellar tumor compressing the optic chiasm. Visual recovery was defined as recovery of mean deviation (MD) and pattern standard deviation (PSD) using Humphrey visual field testing after 12 successful decompressions (24 eyes). Receiver operating characteristic curve (ROC) analysis was used to identify the best thresholds. Robust global and focal OCT thresholds were found. Superior GCC≥63μm had the best functional prognostic value (AUC=1) for visual improvement. Mean GCC ≥ 67μm and mean RNFL≥75μm also had excellent predictive values (AUC>0.9). In this preliminary study, significant preoperative OCT thresholds for early visual recovery after chiasmal decompression were identified, mainly regarding GCC measurements. Further studies on larger cohorts with closely scheduled follow-up could refine our results.

Optical Coherent Tomography Predicts Long-Term Visual Outcome of Pituitary Adenoma Surgery: New Perspectives From a 5-Year Follow-up Study.

Compressive optic neuropathy is the most common indication for transsphenoidal surgery for pituitary adenomas. Optical coherence tomography (OCT) is a useful visual assessment tool for predicting postoperative visual field recovery. To analyze visual parameters and their association based on long-term follow-up. Only pituitary adenoma patients with abnormal visual field defects were selected. A total of 188 eyes from 113 patients assessed by visual field index (VFI) and 262 eyes from 155 patients assessed by mean deviation (MD) were enrolled in this study. Postoperative VFI, MD, and retinal nerve fiber layer (RNFL) thickness were evaluated and followed up. After classifying the patients into normal (>5%) and thin (<5%) RNFL groups, we investigated whether preoperative RNFL could predict visual field outcomes. We also observed how RNFL changes after surgery on a long-term basis. Both preoperative VFI and MD had a linear proportional relationship with preoperative RNFL thickness. Sustained improvement of the visual field was observed after surgery in both groups, and the degree of improvement over time in each group was similar. RNFL thickness continued to decrease until 36mo after surgery (80.2±13.3μm to 66.6±11.9μm) while visual field continued to improve (VFI, 61.8±24.5 to 84.3±15.4; MD, -12.9±7.3dB to -6.3±5.9dB). Patients with thin preoperative RNFL may experience visual recovery similar to those with normal preoperative RNFL; however, the probability of normalized visual fields was not comparable. RNFL thickness showed a strong correlation with preoperative visual field defect. Long-term follow-up observation revealed a discrepancy between anatomic and functional recovery.

Prognostic Utility of Optical Coherence Tomography for Long-Term Visual Recovery Following Pituitary Tumor Surgery

To investigate the association between optical coherence tomography (OCT) parameters and long-term visual recovery following optic chiasm decompression surgery. Prospective cohort study. Consecutive patients who underwent pituitary or parasellar tumor resection between January 2009 to December 2018 were recruited in a single-center, 2-year prospective, longitudinal cohort study. Best-corrected visual acuity, visual fields, and OCT retinal nerve fiber layer (RNFL) thickness, macular thickness and volume were assessed preoperatively, and at 6weeks, 6months, and 2 years postoperatively. Long-term visual field recovery and maintenance were defined as a mean deviation of >-3 at 24months, and visual acuity recovery and maintenance were defined as a logarithm of minimal angle of resolution (logMAR) of 0 (Snellen 20/20) or better at 24months. A total of 239 patients (129 men, 110 women; mean ± SD age: 52 ± 16 years) were included. Multiple logistic regression analysis demonstrated that increased inferior RNFL thickness (per 10μm) was associated with higher odds of long-term visual field recovery and maintenance (odds ratio [OR]: 1.26; 95% confidence interval [CI]: 1.12-1.41; Q < 0.001), and greater superior RNFL thickness (per 10μm) was associated with higher odds of visual acuity recovery and maintenance (OR: 1.13; 95% CI: 1.03-1.27; Q= 0.031). A multivariable risk prediction model developed for long-term visual field recovery and maintenance that incorporated age, preoperative visual function, and RNFL thickness demonstrated C-statistics of 0.83 (95% CI: 0.72-0.94). Preoperative RNFL thickness was associated with long-term visual recovery and maintenance following chiasmal decompression. The multivariable risk prediction model developed in the present study may assist with preoperative patient counseling and prognosis.

Association Between Structure-function Characteristics and Visual Field Outcomes in Glaucoma Subjects With Intraocular Pressure Reduction After Trabeculectomy.

Improvements in post-trabeculectomy visual field (VF) outcomes were found to be significantly associated with preoperative nerve fiber layer thickness parameters extracted from the sectorized structure-function relationship, baseline VF, and severity of glaucoma. To determine whether the preoperative structure-function relationship helps to predict visual outcomes at 1-year post-trabeculectomy. In total, 91 eyes from 87 participants who successfully underwent trabeculectomy were included in our study. All eyes received optical coherence tomography imaging and VF assessment using 30-2 standard automated perimetry preoperatively at baseline and postoperatively 1 year after trabeculectomy. The linear mixed-model analysis was used to assess the association of structure and function at baseline, and multivariate analysis to investigate factors associated with postoperative VF outcomes. Results from multivariate and univariate analysis for VF 1 year after trabeculectomy showed that a positive preoperative retinal nerve fiber layer thickness deviation from the structure-function model was found to be significantly associated with improved postoperative VF outcomes [β=0.06 dB/μm; 95% confidence interval (CI), 0.03-0.09]. Other significant factors included baseline VF MD (β=-0.18; 95% CI, -0.23 to -0.13) and the presence of severe glaucoma (β=-1.69; 95% CI, -2.80 to -0.57). Intraocular pressure was positively associated with improved VF outcomes only in univariate analysis (β=0.06; 95% CI, 0.01-0.11). Characteristics derived from the baseline structure-function relationship were found to be strongly associated with postoperative VF outcomes. These findings suggest that the structure-function relationship could potentially have a role in predicting VF progression after trabeculectomy.

The effect of retrobulbar anesthesia for cataract surgery on the retinal nerve fiber layer thickness.

The aim of this study was to evaluate the effect retrobulbar and topical anesthesia on optic nerve by measuring retinal nerve fiber layer (RNFL) thickness before and after phacoemulsification cataract surgery using optical coherence tomography (OCT). A total of 126 eyes of 108 patients were included in the study. Retrobulbar anesthesia was used in 61 eyes of 53 patients, and topical anesthesia was used in 65 eyes of 55 patients. OCT scans were done 1week before the surgery and 4weeks after surgery, and the results were evaluated. The average RNFL thickness increased postoperatively in both groups (p < 0.001 for topical anesthesia group and p = 0.001 for retrobulbar anesthesia group). The preoperative and postoperative average and quadrant RNFL thickness and the change in RNFL thickness were not significantly different between the two anesthesia groups (p > 0.05). Our results suggest that retrobulbar anesthesia has no unfavorable effect on the retinal nerve fiber layer.

The Effects of Surgical Treatment on Retina-Choroidal Findings in Patients With Obstructive Sleep Apnea Syndrome

The purpose of this study was to determine the effect of surgical treatment on ocular findings in obstructive sleep apnea syndrome (OSAS). The authors studied 34 eyes of 34 newly diagnosed OSAS patients. The sleep study was performed before and 6 months after expansion sphincter pharyngoplasty (ESP). Retinal nerve fiber layer (RNFL), choroidal thickness (CT), and retinal arteriolar caliber (RAC) analyses were performed using spectral-domain optical coherence tomography. Intraocular pressure (IOP) and ocular pulse amplitude were performed using the Pascal dynamic contour tonometer. The preoperative and postoperative Apnea Hypopnea Index scores and average oxygen saturation values were significantly different (P = .0001 and P = .001, respectively). There was no significant difference between the preoperative and postoperative RNFL thicknesses (P > .05). The preoperative subfoveal, nasal, temporal CT, and IOP were significantly different from the postoperative measurements (P = .006, P = .05, P = .036, and P = .0001, respectively). ESP had a significant influence on CT and IOP in patients with OSAS, maintaining a decrease in CT and IOP 6 months after surgery. The determination of these ocular findings may be useful to show the positive effects of ESP. [Ophthalmic Surg Lasers Imaging Retina. 2020;51:35-42.].

Segmented retinal layer analysis of chiasmal compressive optic neuropathy in pituitary adenoma patients.

To evaluate changes in the segmented retinal layers of pituitary adenoma (PA) patients and to identify the relationship between these changes and visual function. A total of 47 (PA patients) and 22 (healthy subjects) eyes were reviewed from the medical records. The PA patients performed a visual field (VF) test before surgery and 1month after surgery. By optical coherence tomography scanning, eight retinal layers were measured: retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer, outer nuclear layer, retinal pigment epithelium, and photoreceptor layer. The PA group showed reduced RNFL, GCL, and IPL thicknesses (p = 0.004,< 0.001,< 0.001) and thicker INL thickness (p = 0.012) than did the controls. The mean deviation of preoperative VF in the PA group was positively correlated with RNFL, GCL, and IPL thicknesses (R = 0.664, 0.720, 0.664; p < 0.001,< 0.001,< 0.001) and negatively correlated with the INL thickness (R = -0.400; p = 0.010). Among the 47 eyes, 32 eyes (68%) were included for subgroup analysis. Preoperative RNFL, GCL, and IPL thicknesses were thicker in the postoperatively improved VF group (p = 0.019, 0.009, 0.005). The preoperative cutoff values for visual recovery were 23.6μm for RNFL thickness, 30.6μm for GCL thickness, and 28.9μm for IPL thickness. During chiasmal compression, the thickening of the INL has presented in addition to thinning of the inner retinal layers. Also, changes in retinal anatomical structures are related to the extent of VF defect and can be used as a predictor of postoperative visual recovery.

Effect of femtosecond laser-assisted lens surgery on the optic nerve head and the macula.

To evaluate the effect of femtosecond laser-assisted lens surgery (FLALS; cataract surgery or refractive lens exchange) on the structure of the optic nerve head and the macula. This prospective longitudinal study included healthy eyes undergoing FLALS. Eyes with glaucoma or any other ocular disease that could alter optical coherence tomography results were excluded. Retinal nerve fiber layer (RNFL), Bruch's membrane opening-minimum rim width (BMO-MRW) and macular thickness (MT) were measured preoperatively, 1 and 6mo after surgery using spectral-domain optical coherence tomography (SD-OCT). Changes between preoperative and postoperative values were evaluated. A total of 87 eyes of 46 patients were included in this study. Preoperative RNFL, BMO-MRW and MT in microns (µm) were 100.77±10.39, 330.31±49.99 and 276.30±33.39, respectively. Postoperative RNFL, BMO-MRW and MT were 104.74±11.55, 348.32±54.05 and 279.83±22.65 1mo after surgery and 102.93±11.17, 343.11±53.4 and 278.90±22.19 6mo after surgery, respectively; which equals an increase of 3.93%, 5.45% and 1.27%, respectively, 1mo after surgery, and 2.14%, 3.87% and 0.94% 6mo after surgery. The differences between the preoperative and the postoperative RNFL and BMO-MRW values were statistically significant (P<0.001). Regarding MT values, there were not statistically significant differences (P=0.26). Our study suggests that FLALS does not have a negative impact on the structural status of the optic nerve head in healthy eyes, assessed by SD-OCT. There is a slight increase in the values of RNFL, BMO-MRW and MT 1mo and 6mo after surgery.

The use of optical coherence tomography in chiasmal compression.

16 patients (32 eyes) with chiasmal compression were included in the study. They presented no other pathology of the visual pathway or of the eye globe. The second inclusion criterion was a subsequent indication of decompressive surgery, either by transcranial or transnasal approach. Measurements of visual acuity, visual field, RNFL and GCL were performed once preoperatively and three times postoperatively (one week, 3 and 6 months postoperatively). The observed peripapillary and perifoveal regions were divided into quadrants. The degree (grade 0-5) of chiasmal compression was determined on preoperative brain MRI (magnetic resonance imaging). In need of some data analysis, participants were split into a group with no or minimal (grade 0-1) and with substantial pressure (grade 2-4) on OC. The median global peripapillary RNFL was 87 &#956;m, the perifoveal nasal GCL 41,2 µm and the temporal 44,2 µm. There was a pronounced preoperative RNFL thinning in nasal (63,5 &#956;m) and temporal (65 &#956;m) quadrant, in comparison to the age-matched normative database for RNFL thickness in the OCT protocol. There is a statistically important connection between bitemporal hemianopia and RNFL, resp. GCL. Larger perimetric outages is related to important OC compression, seen on MRI. There exists a correlation between the thickness of the peripapillary RNFL, resp. perifoveal GCL, and visual field defects in chiasmal compression. Thinner preoperative RNFL does not present a statistically important limiting factor for better functional outcomes after surgical decompression. Horizontal asymmetry of perifoveal GCL is an indicator of compressive ophthalmopathy. The grade of preoperative OC compression presents another important prognostic factor.

The role of optical coherence tomography in the evaluation of compressive optic neuropathies.

Optical coherence tomography (OCT) is a noninvasive imaging tool routinely used in ophthalmology that provides cross-sectional images of the retina. Compression of the anterior visual pathways results in progressive thinning of the retinal nerve fiber layer (RNFL) and macular ganglion cell complex (GCC) and this review will highlight the utility of OCT in evaluating patients with this condition. The RNFL and macular GCC have been found to highly correlate with visual function in patients with compressive optic neuropathies. Preoperative RNFL and macular GCC thickness have emerged as the most reliable and consistent prognostic factors for visual recovery after surgery. Patients with an otherwise normal neuroophthalmic examination, including automated perimetry, may have macular GCC or RNFL thinning as the only manifestation of compression, enabling compressive optic neuropathies to be diagnosed at an earlier stage and managed accordingly. Recent findings indicate that OCT is an important tool in the evaluation of patients with compressive optic neuropathies, particularly for prognosis in patients with visual field defects and diagnosis in patients with preserved or mildly reduced visual function. Anatomical changes detected by OCT may precede visual loss and allow for earlier diagnosis and presumably better visual outcomes.

Optical coherence tomography as a predictor of visual recovery in patients with pituitary macroadenomas

ResumenIntroducción:Los macroadenomas hipofisarios tienen una elevada incidencia de pérdida visual como consecuencia de la compresión de la vía óptica. La tomografía de coherencia óptica (TCO) ha sido descripta como un factor pronóstico de recuperación. Nuestro objetivo es evaluar si la TCO puede predecir los resultados de recuperación visual.Métodos:Se realizó un trabajo prospectivo de macroadenomas hipofisarios con compresión de la vía visual e indicación quirúrgica entre febrero del 2015 y noviembre del 2016. Se evaluaron los estudios de agudeza visual, perimetría computarizada y TCO. Se compararon los resultados tras 6-12 semanas y 6-9 meses de la intervención. Las variables cuantitativas continuas dependientes e independientes se relacionaron mediante una prueba T de Student, regresión lineal y correlación de Pearson considerando como estadísticamente significativo una P < 0,05.Resultados:La alteración en la agudeza visual y la perimetría computarizada preoperatorios, fue mayor en aquellos pacientes con TCO alterada. Tanto los pacientes con CFNR normal como adelgazada se constató una mejoría significativa del campo visual a las 6-12 semanas. Los valores de TCO se correlacionaron en forma inversa con los valores de campo visual, lo que significa que a mayor grosor menor es el déficit campimétrico. Los pacientes con TCO normal tuvieron una mejor recuperación ya que el defecto campimétrico preoperatorio fue más leve. La correlación entre los valores de TCO y la mejoría del campo visual no fue significativa, lo que sugiere independientemente del grosor del nervio los pacientes mejoran el campo visual tras la cirugía.Conclusión:El campo visual computarizado continúa siendo el estudio de elección en la evaluación de pacientes con macroadenomas. La TCO no se considera un predictor de outcome visual.

Retinal nerve fiber layer thickness after laser-assisted subepithelial keratomileusis and femtosecond LASIK: a prospective observational cohort study.

PurposeBased on the assumption that high levels of intraocular pressure (IOP) during femtosecond laser-assisted in situ keratomileusis (FS-LASIK) may compromise the retinal nerve fiber layer (RNFL), newer femtosecond platforms that operate without causing significant IOP elevation have been developed in recent years. However, this assumption has not been adequately tested. The aim of the current study was to evaluate possible changes in RFNL thickness in nonglaucomatous myopic patients undergoing FS-LASIK using the 60 KHz IntraLase® device that significantly elevates the IOP for an appreciable period of time vs an advanced surface ablation technique (laser-assisted subepithelial keratomileusis, LASEK) that does not induce any IOP elevation.MethodsThis was a prospective, observational, controlled cohort study. One randomly selected eye of 114 consecutive eligible patients was analyzed. Inclusion criteria were myopia up to -6.00 diopters and astigmatism up to -2.00 diopters. As clinically indicated, 50 patients underwent LASEK and 64 underwent FS-LASIK. The RNFL thickness was determined with a spectral-domain optical coherence tomography device preoperatively and 3 months postoperatively by the same masked observer.ResultsThere was no significant difference in preoperative refractive error, age, or sex between the groups. Preoperatively, central corneal thickness was significantly lower in the LASEK group (529.1±36.1 vs 562.4±31.6 µm, P=0.001). For the LASEK group, there was no significant difference between preoperative and postoperative RNFL thickness in the studied sectors (superior-temporal, temporal, inferior-temporal, average). For the FS-LASIK group, compared to preoperative RNFL measures, statistically significant thicker postoperative values were found for the average RNFL (mean difference: 0.67 µm, 0.7% increase, P=0.008) and the inferior-temporal sector (mean difference: 0.92 µm, 0.6% increase, P=0.02).ConclusionLASIK with a femtosecond platform that induces high intraoperative IOP did not cause RNFL thinning. The observed differences between preoperative and postoperative values are below the axial resolution limit of optical coherence tomography devices.