Clinical outcomes of topography-guided versus wavefront-optimized LASIK for correction of myopia and compound myopic astigmatism.

PURPOSE: To compare the safety, efficacy, and visual outcomes of topography-guided (TG) LASIK ablation versus advanced ablation algorithm (AAA) on Zeiss Mel 90 on virgin eyes. SETTING: A tertiary care hospital in north India. DESIGN: A retrospective comparative study. METHODS: Case sheets of 30 patients who underwent TG LASIK and 45 patients who underwent AAA LASIK between January 2021 and September 2022 were retrieved and reviewed. The TG group included 60 eyes of 30 patients, and the AAA group included age- and sex-matched 90 eyes of 45 patients. Both groups were compared for visual outcomes, residual refraction, and root-mean-square higher-order aberrations (rms HOA) at 1 week, 1 month, 3 months, and 6 months postoperatively and using unpaired t -test and Mann-Whitney U test. RESULTS: The mean preoperative spherical equivalent in the TG group and AAA group was - 3.12 (1.67) and - 3.19 (1.61), respectively. The safety and efficacy of the treatment were 100% in both groups. The postoperative increase in rms HOA was comparable in both groups ( P = 0.55). The ablation duration was significantly longer in topo-guided LASIK ( P = 0.001). CONCLUSION: AAA LASIK on MEL 90 is comparable to topography-guided LASIK for the management of low myopia and myopic astigmatism.

Visual axis opacification after pediatric cataract surgery - An analysis of morphology and etiology.

PURPOSE: To investigate the morphological types and delineate the clinical and surgical variables associated with VAO in children undergoing pediatric cataract surgery. METHODS: We included 33 eyes of 28 children who developed clinically significant visual axis opacification (VAO) after congenital or developmental cataract surgery. All eyes underwent a comprehensive examination under anesthesia followed by a membranectomy to clear the visual axis. We classified VAO into three subgroups: fibrotic, proliferative, and combined morphologies. We reviewed and analyzed the retrospective data and the findings during membranectomy to identify the etiological variables associated with various morphologies of VAO. RESULTS: The median age at primary surgery was 7 (2-96) months. The median interval from primary surgery to the first documentation of VAO was 6 (1-22) months. Younger children developed VAO sooner than older children. VAO was fibrotic in 11 eyes (33%), proliferative in 18 eyes (54.5%), and combined in four eyes (12.12%). Most children with fibrotic VAO belonged to economically disadvantaged sections of society (P = 0.04). CONCLUSION: Lower age at primary surgery was the predominant risk factor for the development of VAO. Besides primary posterior capsulotomy and adequate anterior vitrectomy, a strict adherence to anti- inflammatory measures and follow up in necessary to prevent the occurrence of VAO. A close follow-up facilitates early detection and management, which can prevent the onset of visually impairing amblyopia.

Inferior rectus muscle Y splitting procedure for near-distance hypotropia disparity: an alternative to the Faden procedure.

A young male patient with unilateral pathological myopia complained of selective hypotropia for distance with exophoria. Due to large globe, a notable amount of inferior scleral show was evident. In this scenario, extensive dissection along inferior rectus muscle to perform a Faden procedure would have worsened the inferior scleral show. Thus, as an alternative, the anterior procedure, that is, "inferior rectus muscle Y-splitting procedure with 4-mm recession" was undertaken. At the end of 3 months follow up, the troublesome selective hypotropia for distance disappeared significantly with very little changes along the lower lid position. Therefore, in presence of specific anatomical limitations, the inferior rectus muscle Y splitting procedure can be considered in lieu of Faden procedure for near-distance hypotropia disparity.

Study 3: Anterior segment optical coherence tomography-guided surgical approach in slipped medial rectus muscle.

Purpose: To discuss the novel swept-source anterior segment optical coherence tomography (SS-ASOCT)-guided surgical approach in slipped medial rectus muscles. Methods: Prospectively (between February 2020 and July 2022), six patients with a clinical suspicion of slipped medial rectus muscle were recruited. After complete ophthalmic and orthoptic evaluation, the missing medial rectus muscle is screened using Anterior Segment Optical Coherence Tomography (ASOCT). In presence of a traceable muscle, its morphology, depth, and distance from a fixed anatomical landmarks were noted; in its absence, the status of other recti was noted. Intraoperatively, the features were confirmed and the intended intervention was performed. Results: The mean age of six patients was 25.66 ± 9.72 years, two with surgical trauma and four with penetrating trauma (66.66%). In five patients, the ASOCT traced the slipped medial rectus muscle successfully (83.33%); intraoperatively, the same was confirmed (within 1-2 millimeters) with favorable outcomes. ASOCT made a significant contribution in all subjects by reducing the number of interventions and muscle surgeries. Conclusions: In eyes with slipped medial rectus muscle, especially those which are within a finite distance from the angle can be traced using ASOCT. This approach impacts the outcomes in many ways.

A pilot randomized clinical trial comparing muscle transplant versus hang back recession in extra-large angle exotropia.

PURPOSE: For extra-large angle exotropia (>60 prism diopters, PD), single-setting surgical alternatives are scarce; frequently, more than two muscle or two eye procedures are indicated. To evaluate the viability of single eye surgery, a current randomized comparative trial is undertaken. METHODS: Twenty adult patients with extra-large angle exotropia underwent a thorough orthoptic evaluation before being divided into two groups at random. Ten patients in group 1 underwent medial rectus resection (5.5-7.5 mm), followed by transplant-aided lateral rectus recession (effective length: 4-5.5 mm) (9 mm). In group two, ten different patients underwent medial rectus resection (5.5-7 mm), but this time, the lateral rectus recession (9 mm) was aided with a hang-back suture (5-7 mm). The two procedures were compared at baseline and six months post-operatively. RESULTS: There was no significant difference in the groups' median ages (P = .95). In groups one and two, the median corrections achieved were 81.00 (79.50-85.50) PD and 81.00 (79.75-86.50) PD, respectively. The differences in corrections were statistically insignificant (p = .99). In all patients, abduction limitation was frequently noted in the immediate post-operative period, which improved over time. In each group, there were two patients (>90 prisms) with residual deviation of at least 30 PD, for which the contralateral eyes were operated. CONCLUSIONS: The hang-back recession was as successful as muscle transplant procedure in correcting 80-90 PD of exotropia with notable clinical benefits and ease.

Anthropometry of deep-set eyes with respect to difficulty in docking during femtosecond laser procedures.

Purpose: To identify the facial anthropometric parameters that predict the difficulty during femtosecond (FS) laser. Methods: This was a: single-center observational study was conducted on participants between the ages 18 and 30 years who were planned for FS-LASIK (femtosecond laser-assisted laser in situ keratomileusis) or SMILE (small incision lenticule extraction) at Dr. Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India. The front and side-facing images of the participants were analyzed using Image J software to measure different anthropometric parameters. The nasal bridge index, facial convexity, and other parameters were measured. The difficulty faced by the surgeon during docking was recorded for each subject. The data were analyzed on Stata 14. Results: A total of 97 subjects were included. The mean age was 24 (±7) years. Twenty-three (23.71%) subjects were females while the rest were males. Difficulty in docking was seen in 1 (4.34%) female and 14 (19%) males. The mean nasal bridge index was 92.58 (±4.01) in subjects with deep-set eyes and 89.72 (±4.30) in normal subjects. The mean total facial convexity was 129.28 (±4.24) in deep-set eyes, and 140.23 (±4.74) in normal subjects. Conclusion: Total facial convexity appeared as the most important feature, with the value being less than 133° in most subjects with unfavorable facial anthropometry.

"Pinch and Stretch" technique to overcome ocular hypotony during scleral suturing of recti muscles.

During extraocular muscle surgery, an uneventful scleral suture pass is very essential. In presence of normal intraocular tension, the surgery is quite predictable and safe. However, in the presence of significant hypotony, it becomes challenging. Therefore, to mitigate complication rate in these cases, we have adopted a simple technique, that is, the "pinch and stretch" technique. The surgical steps of this technique are as follows: In eyes with significant ocular hypotony, the surgery is initiated with a routine forniceal/limbal peritomy, following which the muscle is sutured and dis-inserted. Using three tissue fixation forceps, the scleral surface is stabilized. Using first forceps, the surgeon rotates the globe toward themself from the muscle stump, and with the remaining two forceps, the assistant pinches and stretches the episcleral tissue in an outward and upward direction just beneath the intended marks. This creates a flat scleral surface with significant firmness. Sutures are passed over this rigid sclera and the surgery is completed without any complications.

Rectus muscle pseudo-adherence syndrome.

Purpose: To describe a clinical entity called "rectus muscle pseudo-adherence syndrome" following buckling surgery. Methods: A retrospective data review was undertaken to analyze the clinical profile of strabismus patients who had developed it following buckling surgery. Between 2017 and 2021, a total of 14 patients were identified. The demography, surgical details, and intraoperative challenges were reviewed. Results: The average age of the 14 patients was 21.71 ± 5.23 years. The mean pre-op deviation was 42.35 ± 14.35 prism diopters (PD) of exotropia, and the mean post-op deviation was 8.25 ± 4.88 PD of residual exotropia at 26.16 ± 19.53 months follow-up. Intraoperatively, in the absence of a buckle, the thinned-out rectus adhered to the underlying sclera with much denser adhesions along its margins. When there was a buckle, the rectus muscle adhered to the outer surface of the buckle again, but less densely, with marginal union into the surrounding tenons. In both scenarios, due to the absence of protective muscle coverings, the rectus muscles were naturally adsorbed onto the immediately available surface in the presence of active healing by the tenons. Conclusion: While correcting ocular deviations following buckling surgery, a false sense of an absent, slipped, or thinned-out rectus muscle is very much possible. This is due to active healing of the muscle with the surrounding sclera or the buckle in a single layer of tenons. This is the rectus muscle pseudo-adherence syndrome, where the culprit is the healing process and not the muscle.

Novel Inferior Oblique Muscle Y Splitting Procedure to Minimize the Anti-Elevation Syndrome: A Pilot Study.

Purpose: To describe novel Y splitting procedure of inferior oblique muscle to mitigate the anti-elevation syndrome. Methods: A pilot, prospective interventional study was undertaken to assess the effect of inferior oblique muscle Y-splitting in patients with unilateral 3+ or more overaction. To correct primary gaze hypertropia and the excyclotorsion, a Y-splitting procedure was performed (along with routine horizontal muscle surgery as per the deviation) in 14 subjects. The effect of surgery was assessed at baseline and at 6 months post-intervention. Results: The mean age of 14 subjects was 25.14±7.70 years. The mean pre-operative hypertropia, excyclotorsion and inferior oblique muscle over-action was 18.42±3.50 PD, 14.14±2.65 degrees, and +3.21±0.42 respectively. Following surgery, this was reduced to 1.57±1.74 PD of residual hypertropia (a net correction of 16.85±2.31 PD, p = 0.005), 3.85±1.46 degrees of residual excyclotorsion (a net correction of 10.28±1.72 degrees, p < 0.05), and +0.28±0.46 of residual inferior oblique over-action (a net correction ~+3) at the end of 6 months. Amongst fourteen patients, three patients still experienced residual/variable anti-elevation effect, and during the study period none of them experienced any adverse event and none of them required any additional surgeries. Conclusion: While anteriorizing the inferior oblique muscle to correct primary gaze hypertropia and the excyclotorsion, a novel "Y splitting" procedure can be followed to achieve the desired results with mitigated anti-elevation effect.

Gonioscopy and Angle-Based Glaucoma Surgical Training on Human Eyes in the Wet Lab.

PRCIS: Human corneoscleral rims provide a low cost model and resource to enhance angle based glaucoma surgical training skills. PURPOSE: To understand the feasibility, utility, and efficacy of a low-cost model for performing anterior chamber angle gonioscopy and micro-surgery on human corneoscleral tissues in wet lab on resident skill enhancement. METHODS: Post-keratoplasty residual corneoscleral rims and/or the expired donor corneoscleral buttons were included for the purpose of this study. Initially, inverted rims were used to demonstrate the basic angle anatomy on a slit lamp bio-microscope. Central hazy cornea was then replaced with an artificial cornea and an artificial anterior chamber to simulate indirect gonioscopy, direct gonioscopy, goniotomy, and other angle-based surgeries. Direct gonioscopy and goniotomy exercises (as a means to simulate intraoperative gonioscopy and other angle-based surgeries respectively) were evaluated quantitatively, and the rest qualitatively. RESULTS: A total of 65 residents were included in the exercise. The mean age was 26.69±1.74 years. Amongst these, 55 ophthalmology residents performed the basic examination, that is, slit lamp mounted angle anatomy examination (n=55) and artificial chamber mounted indirect gonioscopic examination through artificial cornea (n=55). In the second exercise, 10 glaucoma fellows performed the direct gonioscopic and the goniotomy exercises on artificial chamber. The fellows demonstrated a statistically significant improvement in interpretation and surgical skill enhancement concurrent with reduction in time taken with increasing number of attempts ( P <0.05). In the third simulation exercise, micro-stent placement within the Schlemm's canal, subconjunctival space, and the suprachoroidal space was re-produced successfully on multiple occasions. CONCLUSIONS: The residual human corneoscleral rims proved to be an important resource for teaching both the basic examination skills and those required for transitioning to advanced intraoperative gonioscopy and goniotomy skills. These low cost, easy to adapt models can be incorporated within the curriculum for improved glaucoma training of both the residents and the glaucoma fellows.

Defining the Clinical Role of Swept-Source Anterior Segment Optical Coherence Tomography in Eyes Undergoing Strabismus Surgery.

Purpose: To describe the clinical role of swept-source anterior segment optical coherence tomography in extraocular muscle imaging in various strabismic conditions. Study Design: Prospective observational study. Participants: A total of 1104 extraocular muscles of 150 subjects were imaged. Normal eyes (640 muscles), eyes undergoing re-operation (240 muscles), paralytic strabismic eyes (16 muscles), non-paralytic strabismic eyes (20 muscles), post-traumatic strabismic eyes (64 muscles), eyes with thyroid disease (64 muscles), and other atypical cases (60 muscles) were imaged. In all cases, up to four recti muscles were evaluated in a given eye depending on the need. Results: The mean age was 38.15 ± 16.25 years. Overall, muscle insertion was identified in over 90% of the subjects. Apart from normal muscles (n = 860, 93.68%), the location was identified in previously operated eyes (n = 54, 90%), in traumatic muscle slippage (n = 2, 11.11%), in ocular coat ectasia (n = 11, 91.66%), in thyroid muscle hypertrophy, in operated scleral fixated intraocular lens with strabismus, and other challenging cases. In all circumstances, clinically useful information was obtained from the anterior 4-14 millimetres of the rectus muscle, which in turn helped in active surgical planning and overall management. Conclusion: The SS-ASOCT with its wider and deeper scanning abilities was able to locate the extraocular muscle insertion in a variety of strabismic conditions. Therefore, this tool can be used in the preoperative periods for optimal surgical planning and management.

Evaluation of reinforced plication as an alternative to resection in exotropia.

PURPOSE: To evaluate the surgical efficacy of reinforced plication of the medial rectus muscle to resection as an effective muscle strengthening procedure in exotropia. METHODS: This is a prospective randomized trial in patients with exotropia who underwent complete orthoptic evaluation followed by random assignment into two groups by using a computer-drawn random number table. Group 1 patients underwent standard resection with recession procedure, and group 2 patients underwent reinforced plication with recession procedure. Follow-up was performed at day 1, 1 week, 1 month, 3 months, and 6 months to assess the surgical efficacy. RESULTS: A total of 80 patients were included in the study of which 39 were in group 1 and 41 in group 2. The mean age in group 1 was 23.48 ± 11.94 years and 23.29 ± 10.02 years in group 2. The mean preoperative deviation in group 1 for distance was 50.13 ± 11.95 PD and 50.12 ± 9.79 PD in group 2 (P = 0.499). In group 1 with a mean surgical dose of 5.27 mm medial rectus resection and 8.04 mm lateral rectus recession, a 7.11 ± 3.95 PD deviation was noted at the end of 6 months. Similarly, in group 2 with a mean surgical dose of 5.16 mm medial rectus plication and 8.16 mm lateral rectus recession, a 6.00 ± 2.46 PD deviation was noted at the end of 6 months. Between groups, ocular surface changes, inter-surgeon comparison, and exotropia subtypes did not reveal any significant differences. CONCLUSION: In our observation, the reinforced medial rectus muscle plication showed clinically comparable results as compared to the standard resection procedure at the end of 6 months. Therefore, this innovative modification can be considered as an alternative to standard resection.

Myopia in India.

India is a culturally and geographically diverse nation. Its vast demographic nature does not allow a single definition for any of the given medical conditions in its territory. One important clinical condition which has created an uproar in the rest of the world is myopia. Its cause, prevalence, etiopathogenesis and other factors are being explored constantly; however, data with respect to Indian subcontinent are genuinely missing. Hence, in this review, we enumerate the country's myopia journey from last 4 decades. The epidemiology, genetics, ocular/systemic association, quality of life, imaging, and management in myopia with necessary future directives are discussed to augment the overall management in future.

Optical coherence tomography angiography in central serous chorioretinopathy: The current clinical role and future perspectives.

Optical coherence tomography angiography (OCTA) images the layers of retinal and choroidal vasculature in the absence of an injectable dye. Since its introduction, OCTA has been utilized in various posterior segment diseases, including central serous chorioretinopathy. We provide a comprehensive review of OCTA's application to central serous chorioretinopathy published between 2014 and 2020.

Simulation of complex strabismus surgical procedures on goat eyes.

PURPOSE: To describe the possibility of complex strabismus surgical simulation on goat eyes. METHODS: The goat eyes were procured from local slaughterhouse with retained extra ocular muscle tissues. The obtained eyes were inspected for globe integrity, muscle quality, muscle length, and the surrounding teno-conjunctival layers. The included eyes were then segregated for surgical simulation based on their insertion and orientation (as oblique or recti), and they were mounted on a mannequin head, with a fixation suture at free end to simulate the resting tension. Additionally, as per necessary, extra muscles were also transplanted along desired sites to simulate human extra ocular muscle anatomy. RESULTS: The inferior oblique, superior oblique, and all other four recti were successfully simulated in varying proportions in more than 50 eyes. Primarily, by simulating the lateral rectus, inferior rectus, and the inferior oblique muscle, staged weakening procedures of inferior oblique were successfully practiced (Fink's recession, Park's recession, Elliot and Nankin procedure, total anterior positioning, and antero-nasal trans-position or Stager's procedure). Similarly, by simulating superior rectus, inferior rectus, lateral rectus, and the medial rectus muscles, half width transposition, full width transposition, and other complex procedures were practiced (Knapp's procedure, augmented Knapp's, Nishida's procedure, Faden operation, and Y splitting procedure). Furthermore, by simulating superior oblique and the superior rectus muscles, superior oblique tuck, posterior tenectomy, loop tenotomy, and Harada Ito procedures were successfully practiced. CONCLUSIONS: On goat eyes, the complex strabismus surgical procedures can be successfully simulated and practiced after re-organizing the existing muscles in different patterns.

Optical coherence tomography angiography in amblyopia: A critical update on current understandings and future perspectives.

Optical coherence tomography angiography (OCTA) is a non-invasive tool to assess the retino-choroidal vasculature in vivo. It tracks the red blood cell movement and maps the vasculature in quick succession. In routine, diabetic retinopathy, age related macular degeneration, central serous chorioretinopathy, and others are commonly being studied to unveil its clinic role. On the other hand, amblyopia is a condition where the visual acuity is subnormal due to non-organic causes in the eye. But the OCTA studies till now have shown variable changes along retino-choroidal vasculature. Hence, to comprehend the existing literature knowledge, a systematic literature search was carried out and the original works describing novel findings in amblyopic eyes on OCTA were included. Upon detailed assessment, firstly, the disturbed vasculature along superficial retinal plexus, deeper retinal plexus, and choroidal plexus were evident in most untreated amblyopic eyes. However, such changes were not uniform, which is due to noted heterogenic patient profile, small sample size, biometric biases, non-uniform algorithms, and other factors. And to note, even in presence of such diverse changes, almost all the authors stated a plausible explanation for their notable changes. Secondly, the utility of OCTA in identifying vascular changes with standard treatments and segregation of visual beneficiaries from non-beneficiaries were possible. Hence, to conclude, OCTA is a valuable tool which can provide valuable useful insights into the amblyopic eyes during pre and post treatment periods. However, to gather more concrete evidence for clinical benefits, systematic, homogenous, and better structured clinical studies are mandated.

Cysticercosis in ophthalmology.

Cysticercosis is caused by Taenia solium, a cestode or tapeworm that preferentially affects the subcutaneous tissue, brain, muscle, and the eye. It is traditionally a disease of low socioeconomic regions, but large-scale population migration has made it a matter of global concern. Its ocular invasion is a potentially blinding disease. In the last two decades, there has been considerable discussion of cysticercosis; however, most comes from a limited number of case observations. Thus, to overcome this limitation, we summarize and analyze twenty years of medical literature (from 2000 to 2020) on cysticercosis in ophthalmology.