Serial intracameral visualization of the Ahmed glaucoma valve tube by anterior segment optical coherence tomography

Purpose

To investigate serial changes of the Ahmed glaucoma valve (AGV) implant tube in the anterior chamber by anterior segment optical coherence tomography (AS-OCT).

Methods

Patients who had received AGV implantation without complications (n=48) were included in this study. Each patient received follow-up examinations including AS-OCT at days 1 and 2, week 1, and months 1, 3, 6, and 12. Tube parameters were defined to measure its length and position. The intracameral length of the tube was from the tip of the bevel-edged tube to the sclerolimbal junction. The distance between the extremity of the tube and the anterior iris surface (T–I distance), and the angle between the tube and the posterior endothelial surface of the cornea (T–C angle) were defined. Factors that were related to tube parameters were analysed by multiple regression analysis.

Results

The mean change in tube length was −0.20±0.17 mm, indicating that the tube length shortened from the initial inserted length. The mean T–I distance change was 0.11±0.07 mm and the mean T–C angle change was −6.7±5.6°. Uveitic glaucoma and glaucoma following penetrating keratoplasty showed the most changes in tube parameters. By multiple regression analysis, diagnosis of glaucoma including uveitic glaucoma (P=0.049) and glaucoma following penetrating keratoplasty (P=0.008) were related to the change of intracameral tube length.

Conclusions

These results suggest that the length and position of the AGV tube changes after surgery. The change was prominent in uveitic glaucoma and glaucoma following penetrating keratoplasty.     

Efficacy of a hinged pupil expansion device in small pupil cataract surgery

Purpose:To evaluate the efficacy and safety of a hinged pupil expansion device (PED) in eyes with small pupils undergoing phacoemulsification.Methods:In this prospective, multicenter, interventional case series of 57 eyes with suboptimal pharmacologic pupil dilation (<5 mm diameter), a hinged PED (I-Ring, Beaver-Visitec International, Waltham, MA) was applied to facilitate surgical visualization during cataract surgery. The pupil diameters (PD) were measured at different stages of the procedure and at the 1-month follow-up visit. Rate of successful intraoperative PED deployment, pupil size, and shape were assessed.Results:The mean patient age was 70.5 ± 12.1 years. The I-Ring PED was successfully applied in all eyes. The mean PD at various stages were 4.1 ± 1.1 mm (dilation with eye drops only preoperatively), 4.3 ± 1.1 mm (dilation after intracameral epinephrine and ophthalmic viscoelastic device), 6.80 ± 0.00 mm (with PED applied), and 5.7 ± 1.1 mm (end of surgery). A statistically significant difference (P < 0.001) was observed between the mean PD with intracameral medications and with PED application. Postoperative circular pupil was observed in 54 of 57 eyes (94.7%) and the mean eccentricity index (n = 57 eyes) was 0.11 ± 0.22. No significant adverse events were observed.Conclusion:The I-Ring PED safely and effectively provided and maintained adequate pupil expansion and surgical visualization in eyes with small pupils undergoing cataract surgery. Postoperatively 95% of eyes attained circular pupils. This hinged PED is an additional instrumentation option for the safe and effective expansion of inadequately sized pupils during cataract surgery.     

The effect of head tilt on keratometric measurement using the IOLMaster

Purpose

To investigate the effect of head tilt on keratometric measurement using the IOLMaster.

Methods

Twenty-seven right eyes of 27 volunteers were examined using a manual keratometer (MK), automated keratometer (AK), and an IOLMaster. MK and AK measurements were performed in the upright head position, whereas IOLMaster measurements were performed in five different head positions (upright, 5° or 15° clockwise head tilt, and 5° or 15° counter-clockwise head tilt). The repeatability of IOLMaster was compared with MK and AK. The keratometric measurements (mean keratometric power, magnitude of astigmatism, and steep meridian) in different head positions were compared.

Results

The IOLMaster showed good repeatability of keratometric measurement comparable to MK or AK. 15° and 5° clockwise head tilt resulted in 12.09±9.51 (mean±SD) (P<0.001 vs upright) and 5.51±5.97 (mean±SD) degrees (P<0.001) of clockwise rotation of steep meridian, respectively. 15° and 5° counter-clockwise head tilt resulted in 12.49±7.07 (mean±SD) (P<0.001) and 6.08±5.09 (mean±SD) degrees (P<0.001) of counter-clockwise rotation of steep meridian, respectively.

Conclusions

The patient''s head tilt (5° or 15°, clockwise or counter-clockwise) significantly changed the steep meridian of astigmatism measured using IOLMaster and the steep meridian generally shifted to the direction of head tilt. The importance of maintaining the upright head posture during IOLMaster measurement is demonstrated.     

Corneal endothelial cells and central corneal thickness in patients with neurofibromatosis type 1

Purpose:The aim of this study was to evaluate the morphological properties of corneal endothelial cells and central corneal thickness (CCT) in patients with neurofibromatosis type 1 (NF1) and to compare them with age-matched healthy controls.Methods:Nineteen NF1 patients and 38 healthy individuals were recruited. All participants underwent complete ophthalmological examination as well as noncontact specular microscopy to measure endothelial cell density (ECD), average cell area (AVG), coefficient of variation of cell area (CV), the percentage of hexagonal cells, and CCT. Eyes with previous ocular trauma, inflammation or surgery, and preexisting corneal and ocular surface diseases were excluded.Results:NF1 patients had higher ECD compared to healthy controls of the same age (2764.2 ± 270.4 versus 2570.4 ± 449.2 cells/mm, respectively), although at a borderline level (P = 0.051). Patients with NF1 presented significantly lower CV and AVG when compared to controls (32.9 ± 4.6 versus 37.8 ± 9.5%, P = 0.011 and 364.9 ± 34.4 versus 406.0 ± 107.4 µm, P = 0.038, respectively). The NF1 group had significantly higher hexagonality in comparison with controls (55.7 ± 6.5 versus 50.5 ± 9.9%, P = 0.025). CCT was similar between the two groups (P = 0.955).Conclusion:Our results show that corneal endothelium has more favorable morphological characteristics in NF1 patients compared to healthy individuals of the same age.     

Differences between Non-arteritic Anterior Ischemic Optic Neuropathy and Open Angle Glaucoma with Altitudinal Visual Field Defect

PurposeTo investigate the differences in retinal nerve fiber layer (RNFL) change and optic nerve head parameters between non-arteritic anterior ischemic optic neuropathy (NAION) and open angle glaucoma (OAG) with altitudinal visual field defect.MethodsSeventeen NAION patients and 26 OAG patients were enrolled prospectively. The standard visual field indices (mean deviation, pattern standard deviation) were obtained from the Humphrey visual field test and differences between the two groups were analyzed. Cirrus HD-OCT parameters were used, including optic disc head analysis, average RNFL thickness, and RNFL thickness of each quadrant.ResultsThe mean deviation and pattern standard deviation were not significantly different between the groups. In the affected eye, although the disc area was similar between the two groups (2.00 ± 0.32 and 1.99 ± 0.33 mm², p = 0.586), the rim area of the OAG group was smaller than that of the NAION group (1.26 ± 0.56 and 0.61 ± 0.15 mm², respectively, p < 0.001). RNFL asymmetry was not different between the two groups (p = 0.265), but the inferior RNFL thickness of both the affected and unaffected eyes were less in the OAG group than in the NAION group. In the analysis of optic disc morphology, both affected and unaffected eyes showed significant differences between two groups.ConclusionsTo differentiate NAION from OAG in eyes with altitudinal visual field defects, optic disc head analysis of not only the affected eye, but also the unaffected eye, by using spectral domain optical coherence tomography may be helpful.     

Retinal Nerve Fiber Layer Thickness Measurement Comparison Using Spectral Domain and Swept Source Optical Coherence Tomography

PurposeTo investigate the retinal nerve fiber layer (RNFL) thickness concordance when measured by spectral domain (SD) and swept source (SS) optical coherence tomography (OCT), and to compare glaucoma-discriminating capability.MethodsRNFL thicknesses were measured with the scan circle, centered on the optic nerve head, in 55 healthy, 41 glaucoma suspected, and 87 glaucomatous eyes. The RNFL thickness measured by the SD-OCT (sdRNFL thickness) and SS-OCT (ssRNFL thickness) were compared using the t-test. Bland-Altman analysis was performed to examine their agreement. We compared areas under the receiver operating characteristics curve and examined sdRNFL and ssRNFL thickness for discriminating glaucomatous eyes from healthy eyes, and from glaucoma suspect eyes.ResultsThe average ssRNFL thickness was significantly greater than sdRNFL thickness in healthy (110.0 ± 7.9 vs. 100.1 ± 6.8 µm, p < 0.001), glaucoma suspect (96.8 ± 9.3 vs. 89.6 ± 7.9 µm, p < 0.001), and glaucomatous eyes (74.3 ± 14.2 vs. 69.1 ± 12.4 µm, p = 0.011). Bland-Altman analysis showed that there was a tendency for the difference between ssRNFL and sdRNFL to increase in eyes with thicker RNFL. The area under the curves of the average sdRNFL and ssRNFL thickness for discriminating glaucomatous eyes from healthy eyes (0.984 vs. 0.986, p = 0.491) and glaucoma suspect eyes (0.936 vs. 0.918, p = 0.132) were comparable.ConclusionsThere was a tendency for ssRNFL thickness to increase, compared with sdRNFL thickness, in eyes with thicker RNFL. The ssRNFL thickness had comparable diagnostic capability compared with sdRNFL thickness for discriminating glaucomatous eyes from healthy eyes and glaucoma suspect eyes.     

Sternocleidomastoid muscle asymmetry in unilateral congenital superior oblique palsy

BackgroundTo determine whether there is an asymmetry in bilateral sternocleidomastoid muscle (SCM) thickness in patients with unilateral congenital superior oblique palsy (SOP) and its association with surgical results.MethodsThe medical records of 186 patients with head tilt secondary to unilateral SOP, who were evaluated for the status of the SCM with neck ultrasound or magnetic resonance imaging, were reviewed. The SCM asymmetry index was calculated as a bilateral difference in the maximal muscle thickness divided by each tilted-side SCM thickness. The presence of SCM asymmetry, defined as an index of >10%, and its relationship to residual torticollis ≥5° after SOP surgery were assessed.ResultsOf 186 patients with a median age of 1.2 years, SCM asymmetry was present in 102 (54.8%) patients (6.8 ± 1.9 mm for the SOP side vs. 6.6 ± 2.1 mm for the tilted side). The SCM asymmetry did not differ according to age, amount of head tilt or hypertropia. In the patients with SCM asymmetry, more patients (87.3%) underwent physiotherapy than those without asymmetry (61.9%) (P = 0.021). In 99 patients who underwent surgery for SOP, the resolution of torticollis was not significantly different between patients with and without SCM asymmetry (87.2% vs. 76.9%, P = 0.184).ConclusionsNearly half of the patients with congenital SOP had SCM thickness asymmetry that was already determined at a young age. However, the surgical results did not differ significantly with respect to SCM asymmetry when physiotherapy was combined. Thus, SOP surgery can be considered despite preoperative SCM asymmetry.Subject terms: Outcomes research, Ocular motility disorders     

Monocular optokinetic nystagmus in humans with age-related maculopathy

AIM—To investigate full field monocular optokinetic nystagmus (OKN) in patients with age-related maculopathy (ARM) and relative central scotoma.
METHODS—Six patients aged 59-88 years with bilateral ARM and an aged-matched control group of six patients aged 54-83 years were examined. Visual fields were assessed with a Humphrey field analyser using the threshold 30-1 routine. Monocular full field horizontal optokinetic stimuli were presented on a hemicylindrical screen subtending 172° horizontally and 50° vertically. The stimulus was a projected random dot pattern and three stimulus velocities were used, 30, 50, and 70°/s in both nasalward and temporalward directions. Each trial lasted between 30 and 40 seconds and eye movements were monitored using infrared oculography.
RESULTS—The ARM patients had relative central scotomas with an average depth of 10 dB. Neither the ARM nor the age-matched groups displayed any directional preponderance or a buildup of the slow phase eye velocity with time. No statistically significant difference in the gain was found between the two groups (p>0.05).
CONCLUSIONS—Marked central field loss in ARM does not significantly impair OKN gain. This supports the view that complete central retinal integrity is by no means essential and that the peripheral retina provides an important input to the generation of OKN.

     

Quantitative Analysis of Translatory Movements in Patients With Horizontal Strabismus

PurposeTo investigate translatory movement during the lateral gaze in patients with horizontal strabismus using magnetic resonance imaging.MethodsPatients with esotropia or exotropia and normal controls underwent orbital magnetic resonance imaging during the central gaze and lateral gaze at 40°. The position of the static tissues was superimposed three-dimensionally for all gazes using a self-developed software, allowing the analysis of the net eyeball movement. Then, the eyeball centroid coordinates were extracted for each gaze, and the distance and direction of centroid movement from the central to lateral gaze were calculated.ResultsThe mean distance ± standard deviation of the centroid movement was 1.0 ± 0.5 mm during abduction in the exotropia group, which was significantly longer than that in the esotropia (0.6 ± 0.3 mm; P = 0.003) and control (0.7 ± 0.2 mm; P = 0.002) groups. Conversely, the centroid moved farther in the esotropia group (0.9 ± 0.3 mm) than the exotropia (0.6 ± 0.3 mm; P = 0.005) and control (0.7 ± 0.2 mm; P = 0.023) groups during adduction. Posterior translation during abduction was longer in the exotropia group (−0.8 ± 0.3 mm) compared with the esotropia (−0.5 ± 0.3 mm; P = 0.017) and control (−0.4 ± 0.3 mm; P = 0.001) groups, whereas that during adduction was longer in the esotropia group (−0.4 ± 0.4 mm) than the exotropia (−0.1 ± 0.2 mm; P = 0.033) and control (−0.1 ± 0.2 mm; P = 0.026) groups.ConclusionsDuring abduction, more translatory movement occurred in the exotropia group, whereas the centroid moved farther in the esotropia group during adduction. The translatory movement difference between both strabismus groups implies that there is a difference in biomechanics among the types of strabismus.     

Efficacy and Safety of Preservative-free Latanoprost Eyedrops Compared with Preserved Prostaglandin Analogues in Patients with Open-angle Glaucoma

PurposeTo evaluate the safety and efficacy of preservative-free (PF) latanoprost in glaucoma patients.MethodsIn this prospective, open-label, observational study, a total of 27 primary open-angle glaucoma patients who used benzalkonium chloride-preserved prostaglandin analogues for at least 6 months were enrolled. After changing the eye drops to PF lataprost, the intraocular pressure (IOP) and ocular surface symptoms and signs were evaluated in all patients on days 0 (first visit, D0), 45 (D45), and 90 (D90).ResultsMean IOP remained stable during the study period (14.0 ± 2.4 mmHg at D0, 13.9 ± 2.0 mmHg at D45, 13.7 ± 2.2 mmHg at D90; p = 0.603). Mean deviation, pattern standard deviation, and best-corrected visual acuity were similar before and after eye drops replacement. Bulbar conjunctival hyperemia, corneal staining, and conjunctival staining were significantly decreased over 90 days (p = 0.025, p < 0.001, p = 0.020, respectively). The ocular surface disease index score showed a statistically significant improvement from 26.4 ± 18.5 at D0 to 19.8 ± 17.0 at D45 and 15.7 ± 15.6 at D90 (p < 0.001). In the evaluation of ocular tolerability, burning symptoms and dryness were significantly decreased (p = 0.001, p = 0.040).ConclusionsThe effects of PF latanoprost on reducing IOP were comparable with those of benzalkonium chloride-preserved prostaglandin analogues, but side effects on the ocular surface were much less pronounced when PF latanoprost was used. With this efficacy, PF latanoprost could slow the progression of glaucoma by increasing patient compliance.     

Our experience of fibrin sealant-assisted implantation of Ahmed glaucoma valve

Aim:

To report our experience with the fibrin sealant as a suture substitute for securing the human scleral patch graft during implantation of Ahmed glaucoma valve (AGV).

Materials and Methods:

A retrospective, non-comparative study of 12 eyes of 12 patients who underwent an AGV implantation with fibrin sealant for part of the procedure during June 2009 to September 2010.

Results:

The mean patient age was 21.5 ± 20.6 years. Male: Female ratio was 2 : 1. Seven (58.3%) patients were monocular. The indications for AGV were varied. The mean number of intra-ocular surgeries prior to an implantation of AGV was 1.8. The mean follow-up duration was 24.5 ± 17.9 weeks. There was a statistically significant reduction in the mean IOP and in the mean number of anti-glaucoma medications at the final visit compared to the pre-operative values (P < 0.01, paired t test). Conjunctival retraction was seen in 1 (8.3%) case. The scleral patch graft was retracted posteriorly in another (8.3%) case. There was no case of AGV tube exposure, tube-cornea touch, or conjunctival erosion. Vision threatening complication viz. late post-operative rhegmatogenous retinal detachment, unlikely to be related to the use of the fibrin sealant, occurred in 2 (16.6%) eyes.

Conclusion:

The fibrin sealant offers the advantages of safety and convenience to the placement of a scleral patch graft during an AGV implantation.     

A pharmacoeconomic analysis to determine the relative cost-effectiveness of bimatoprost 0.03% eye drops and brimonidine 0.2% eye drops in patients of primary open-angle glaucoma/ocular hypertension

Aims:The aim was to compare efficacy and cost-effectiveness of bimatoprost 0.03% and brimonidine 0.2% in primary open-angle glaucoma (POAG)/ocular hypertension (OHT).Statistics:Independent samples t-test was used to compare the efficacy of both drugs.Results:IOP lowering with bimatoprost (8.9 ± 1.598 mm Hg) was significantly (P < 0.0001) higher than brimonidine (6.55 ± 1.26 mm Hg). The number of drops/ml were 33.43 ± 0.52 and 25.49 ± 0.26, respectively, for bimatoprost and brimonidine. Treatment with bimatoprost was costlier than brimonidine with daily costs/eye Rs. 4.02 ± 0.06 and 3.14 ± 0.03, yearly costs/eye Rs. 1467.46 ± 20.74 and 1147.75 ± 11.15, respectively. Bimatoprost was more cost-effective than brimonidine with the cost-effectiveness ratio (CER) respectively Rs. 13.10 ± 2.61/mm Hg and Rs. 13.96 ± 2.86/mm Hg. Incremental CER Rs. 10.43/mm Hg implies lower costs/mm Hg extra IOP lowering by bimatoprost than Rs. 13.96 for brimonidine.Conclusion:In spite of being costlier, bimatoprost is more efficacious and cost-effective than brimonidine.     

Posture-Dependent Collapse of the Optic Nerve Subarachnoid Space: A Combined MRI and Modeling Study

PurposeWe hypothesize that a collapse of the optic nerve subarachnoid space (ONSAS) in the upright posture may protect the eyes from large translamina cribrosa pressure differences (TLCPD) believed to play a role in various optic nerve diseases (e.g., glaucoma). In this study, we combined magnetic resonance imaging (MRI) and mathematical modeling to investigate this potential ONSAS collapse and its effects on the TLCPD.MethodsFirst, we performed MRI on six healthy volunteers in 6° head-down tilt (HDT) and 13° head-up tilt (HUT) to assess changes in ONSAS volume (measured from the eye to the optic canal) with changes in posture. The volume change reflects optic nerve sheath (ONS) distensibility. Second, we used the MRI data and mathematical modeling to simulate ONSAS pressure and the potential ONSAS collapse in a 90° upright posture.ResultsThe MRI showed a 33% decrease in ONSAS volume from the HDT to HUT (P < 0.001). In the upright posture, the simulations predicted an ONSAS collapse 25 mm behind lamina cribrosa, disrupting the pressure communication between the ONSAS and the intracranial subarachnoid space. The collapse reduced the simulated postural increase in TLCPD by roughly 1 mm Hg, although this reduction was highly sensitive to ONS distensibility, varying between 0 and 4.8 mm Hg when varying the distensibility by ± 1 SD.ConclusionsThe ONSAS volume along the optic nerve is posture dependent. The simulations supported the hypothesized ONSAS collapse in the upright posture and showed that even small changes in ONS stiffness/distensibility may affect the TLCPD.     

Clinical features and microbiology of post-cataract surgery endophthalmitis with and without intracameral moxifloxacin prophylaxis: Endophthalmitis prophylaxis study report 3

Purpose:This study aimed to analyze the clinical presentations, microbiology, and management outcomes of post–cataract surgery endophthalmitis, with and without intracameral moxifloxacin prophylaxis.Methods:This study was designed as a retrospective, consecutive, comparative case series. Records of consecutive cataract surgery from January 1, 2015, till June 30, 2020, were analyzed. The cases that developed endophthalmitis were analyzed. The endophthalmitis cases were divided by their prophylaxis treatment into two groups: with intracameral moxifloxacin (ICM) and without (N-ICM). Inclusion criteria were (1) age ≥ 18 years, (2) cataract surgery with intraocular lens implantation, (3) endophthalmitis within 6 weeks of cataract surgery, and (4) cataract surgery in the institute by any of the three methods—phacoemulsification, manual small incision cataract surgery, and extracapsular cataract extraction.Results:In the study period, 66,967 cataract surgeries were performed; 48.7% (n = 32,649) did not receive ICM. There was no difference between the N-ICM and ICM groups in the incidence of clinical (n = 21, 0.064% and n = 15, 0.043%; P = 0.23) and culture proven (n = 19, 0.033% and n = 11, 0.023%; P = 0.99) endophthalmitis, respectively. Greater number of patients in the N-ICM group had lid edema (76.2% vs. 40%; P = 0.03), corneal edema (71.4% vs. 33.3%; P = 0.03) and lower presenting vision with available correction (logMAR [logarithm of the minimum angle of resolution] 1.26 ± 1.2 vs. logMAR 0.54 ± 0.85; P = 0.02). The final best-corrected visual acuity following treatment was worse in the N-ICM group (logMAR 1.26 ± 1.2 vs. 0.54 ± 0.85; P = 0.02).Conclusion:Endophthalmitis after intracameral moxifloxacin may have relatively milder signs and symptoms and may respond better to treatment.     

Utilization rate of corneal tissue obtained from donors over 75 years of age in Western India for keratoplasty

Purpose:To examine the utilization patterns of cornea procured from diseased individuals ≥75 years of age at an eye bank in western India.Methods:In this retrospective study, data from 1,217 eyes of 653 donors with age ≥75 years were reviewed from October 2008 to December 2019. Donor age, lens status, endothelial cell count (ECD), utilization of the tissue for transplantation or non-clinical purposes (e.g., research, training/discarded), and causes of non-utilization were noted.Results:The mean age of the donors was 80.9 ± 4.6 years and the tissue utilization rate was 36.5% (445 out of 1,217 eyes). The eyes used for keratoplasty procedures had a lower donor age (79.6 ± 5.7 vs. 81.5 ± 5.1; P < 0.001), a higher endothelial cell count (2493 ± 531 vs. 2034 ± 581; P < 0.001), and were more often phakic (61% vs. 36.6%) compared to the unused group. A multivariable logistic regression analysis showed that the likelihood of tissue utilization for keratoplasty was 13% higher with every 100-cell increment in donor ECD (odds ratio [OR] = 1.13, 95% CI = 1.10–1.16, P < 0.001) and 33% lower with having a pseudophakic status in the donor eye (OR = 0.67, 95% CI = 0.52–0.87, P = 0.03). Age was not a significant determinant of tissue utilization when used in the same multivariable model.Conclusion:More than one-third of the eyes (36.5%) can be utilized even when the donors are above 75 years of age. Eyes that were more likely to be utilized for keratoplasty were phakic and had a significantly higher ECD; age was not a determinant in tissue utilization.     

The Effect of a Diving Mask on Intraocular Pressure in a Healthy Population

PurposeSwimming goggles increase the intraocular pressure (IOP) via the periorbital frame pressure and suction effect. In comparison, diving masks have a larger frame rim and incorporate the nose. The exact effect(s) of diving masks on IOP is unknown. This study evaluates the influence of diving masks on IOP in normal, healthy subjects.MethodsTonometry was performed in both eyes of all subjects with an AVIA^®Tono-Pen by a single investigator. Measurements were taken at baseline without the diving mask and with the subjects wearing a small-volume, double-window diving mask, but with the mask lenses removed. Two IOP readings in each eye were measured, and an additional reading was measured if the difference between the initial 2 was ≥2 mm Hg. Central corneal thickness (CCT) was also measured in each eye, using a contact pachymeter (OcuScan^®Alcon).ResultsForty eyes of 20 healthy volunteers (age 29.7 ± 9.3 years; range 21–52) were included. The mean CCT was 544.4 ± 43.5 µm. The mean IOP before the diving mask was worn had been 17.23 ± 2.18 mm Hg (n = 40). The IOP decreased by 0.43 mm Hg (p $1003c; 0.05) to 16.80 ± 2.57 mm Hg after the diving mask had been put on. There was no correlation between IOP change and age (r = 0.143, p = 0.337), gender (r = −0.174, p = 0.283) or CCT (r = −0.123, p = 0.445).ConclusionThere was no increase in IOP after the diving mask had been worn. A small but statistically significant decrease in IOP was observed. This study demonstrates that unlike swimming goggles, the strap tension and frame pressure on the periorbital tissue from a diving mask does not increase IOP. Diving masks may be a suitable alternative to swimming goggles for patients with advanced glaucoma or glaucoma filtration surgery.     

Nomogram of peripapillary retinal nerve fiber layer thickness in myopic eyes of north Indian population

Purpose:To evaluate peripapillary-RNFL thickness in myopia by Cirrus OCT among north Indian population by spherical equivalent (SE), age, gender, and axial length (AL).Methods:This was a cross-sectional study held during 2019–2020. Patients aged 18–60 years underwent ophthalmic examination including retinoscopy, AL, and OCT RNFL thickness. Persons with previous ocular surgery or ocular ailment other than refractive error were excluded. The peripapillary-RNFL thickness was noted and compared by demographic determinants.Results:We examined 300 eyes of 300 persons (mean age: 30.75 ± 8.57 years; 144 males/156 females). Among them, 224 were myopes and 76 were emmetropes (EM). The mean SE was − 3.3 ± 0.4D (range: −11.0D to + 0.37D). The mean AL was 24.61 ± 1.92 mm (22.1–29.5). Overall temporal, nasal, superior, inferior, and mean peripapillary-RNFL thickness was 66.31 ± 7.58, 78.57 ± 16.00, 120.63 ± 11.69, 116.60 ± 15.80, and 95.50 ± 10.84 mm, respectively. Temporal, nasal, superior, inferior, and mean peripapillary-RNFL thickness was 73.97 ± 8.36, 94.84 ± 7.63, 127.96 ± 8.96, 136.89 ± 6.53, and 108.34 ± 6.28 mm, respectively, in EM eyes as compared to 63.71 ± 6.18, 73.05 ± 14.24, 118.21 ± 11.53, 109.71 ± 11.50, and 91.14 ± 8.31 mm, respectively, in myopic eyes (P < 0.001). Association of peripapillary-RNFL thickness with myopia and its different grades was P < 0.001. Association of mean peripapillary-RNFL thickness with age was P > 0.005 and gender was P = 0.168. Correlation between SE and RNFL thickness was positive and significant. Correlation between AL and RNFL thickness was negative but statistically significant. Association of AL with SE was P < 0.001.Conclusion:We provide normative peripapillary-RNFL thickness in the north Indian population in order to help in screening for myopia with comorbidity such as glaucoma based on RNFL thickness.     

Surgical Outcomes of Nonadjustable Modified Harada-Ito Surgery

PurposeThis study aimed to investigate the surgical outcomes of nonadjustable Harada-Ito surgery under general anesthesia.MethodsTwenty-two patients who underwent nonadjustable modified Harada-Ito surgery under general anesthesia were reviewed retrospectively. Among them, 21 out of the 22 patients who were followed up for 6 months after surgery were included in this study. Subjective cyclotorsion (double Maddox rod test) and objective cyclotorsions (fundus photography) were measured. Success of the surgery was defined as follows: success (the patients do not acknowledge diplopia at any direction), partial (the patients feel diplopia at a specific direction, but they do not feel discomfort in routine life), and fail (the patients feel diplopia in primary gaze, hence requiring a thorough investigation).ResultsThe mean age of the patients (18 male and 3 female) was 56.5 years (range, 40–77 years). Based on the alternate prism cover test, the patients had 4.2 ± 3.0 prism diopters of vertical deviation. The corrected amounts of cyclotorsion based on the double Maddox rod test and fundus photography were 14.8° ± 7.5° and 9.8° ± 7.9°, respectively, and were significantly different between the two methods (p = 0.006). After the surgery, 20 out of the 21 patients (95.2%) completely recovered from diplopia in the primary gaze. However, among the 20 patients, seven complained of diplopia in the secondary gaze (down gaze, four patients; head tilt gaze, three patients). The success group had a smaller preoperative subjective excyclotorsion than the partial and fail groups (12.6° ± 2.5° and 21.0° ± 8.9°, respectively; p = 0.046).ConclusionsNonadjustable modified Harada-Ito surgery under general anesthesia has favorable success rate, and preoperative subjective excyclotorsion can be a prognostic factor in patients with bilateral superior oblique palsy.     

Location of Parapapillary Gamma Zone and Vertical Fovea Location. The Beijing Eye Study 2011

PurposeTo assess the spatial relationship between the locations of the parapapillary gamma zone and the fovea.MethodsIn a non-glaucomatous subgroup of the population-based Beijing Eye Study population, we measured the mean angle between the optic disc–fovea line and the horizontal (disc–fovea angle), the vertical distance of the fovea from the horizontal through the optic disc center (fovea vertical distance), and the location and width of the widest part of parapapillary gamma zone.ResultsThe study included 203 individuals (203 eyes; mean axial length, 24.4 ± 1.5 mm; range, 22.03–28.87 mm). The widest gamma zone part was located most often temporal horizontally (51.7%), then inferiorly (43.8%), superiorly (2.5%), and nasally (2.0%). The disc–fovea angle (mean, 7.50° ± 4.00°; range, –6.30° to –23.25°) was significantly higher (P = 0.003; i.e., fovea located more inferiorly) in eyes with the widest gamma zone inferiorly (8.46° ± 4.37°) than in eyes with the widest gamma zone temporally (6.71° ± 3.46°) and in eyes with the widest gamma zone temporally, superiorly, or nasally combined (6.75° ± 3.53°; P = 0.003). The fovea vertical distance (mean, 0.65 ± 0.33 mm; range, –0.20 to 1.67 mm) was longer (P = 0.001; i.e., fovea located more inferiorly) in eyes with the widest gamma zone inferiorly (0.73 ± 0.33 mm) than in eyes with the widest gamma zone temporally (0.58 ± 0.30 mm) and in eyes with a temporal, superior, or nasal gamma zone combined (0.58 ± 0.31 mm; P = 0.001). The fovea vertical distance increased (multivariate analysis) with the widest gamma zone location inferiorly (β = 0.25; P = 0.001) and wider width of the gamma zone (β = 0.19; P = 0.01).ConclusionsAn inferior fovea location is associated with a wider inferior gamma zone and vice versa, supporting the notion of an inferior shifting of Bruch''s membrane as the cause for an inferior gamma zone.     

Surgical strategy for third nerve palsy with aberrant regeneration: Harnessing the aberrant power

Purpose:Our study aimed to evaluate the outcome of contralateral eye (CE) fixation duress squint surgery (FDSS) in third nerve palsy (3^rd NP) with aberrant regeneration and compare the postoperative ptosis correction with preoperative ptosis improvement on adduction.Methods:Patients of 3^rd NP with aberrant regeneration who underwent CE FDSS between December 2012-July 2015 in a tertiary-care eye hospital with a follow-up period of 1-year were retrospectively studied to analyze preoperative and postoperative details. Surgical success was defined as the correction of ptosis within 1 mm of preoperative ptosis improvement during maximal adduction of the affected eye, postoperative alignment ≤10Δ, and resolution of subjective diplopia in primary position.Results:A total of 14 eyes in 14 patients (mean age 23.6 ± 13.6 years) were included. Mean preoperative exotropia and ptosis in primary position in 14 patients was 53.4 ± 20pd and 4.89 ± 2.9 mm, respectively, and mean hypotropia in 6 patients was 23.67 ± 5.89pd. The mean improvement of ptosis on adduction and supraduction in all patients was 4.07 ± 2.64 mm and 2.89 ± 2.22 mm, respectively (P = 0.213). All patients underwent large recession of CE lateral rectus (mean 12.4 ± 2.7 mm), 9 patients underwent CE medial rectus resection/plication (mean 6.0 ± 0.9 mm) and 6 patients underwent CE superior rectus recession (mean 6.6 ± 0.67 mm). Postoperatively, mean ptosis and exotropia correction was 3.7 ± 2.4 mm (P = 0.000) and 15 ± 9.6pd (P = 0.000), respectively, and mean hypotropia was 2.17 ± 4.02pd (P = 0.000). Surgical success was achieved in 6 patients. Postoperative ptosis correction showed strong positive correlation with preoperative improvement of ptosis on adduction (r = 0.87; P = 0.00).Conclusion:Preoperative lid excursion on adduction in 3^rd NP can be regarded as a prognostic sign of the success of CE FDSS which can simultaneously correct both ptosis and squint.