Slit-lamp assisted TORic Marker (STORM): A novel corneal axis marker.

Background: Toric Intraocular lenses (IOLs) are supposed to be aligned at a particular axis for spectacle-free vision for distance. The evolution of topographers and optical biometers has made it quite achievable for us to aim the target. However, the result sometimes remains unpredictable. A big aspect of this depends on the preop axis marking for toric IOL alignment. Errors in axis marking have been reduced recently with the array of different toric markers in the market, but still we see postoperative refractive surprises due to faulty marking. Purpose: In this video, we present a novel slit lamp-based toric marker innovation, STORM, which gives us a hands-free approach to a reliable and accurate axis marking on the cornea. The axis marker is a simple modification to our age-old marker, with the advantage of no touch and slit-lamp assistance, which will make it error free and easy to use. Synopsis: The present innovation answers the problem statement of stable, economical, and accurate marking solution. Many a times, hand-holding devices create inaccurate and stressed condition while marking the cornea before corneal surgery. Highlights: The invention can be used for marking of accurate and easy astigmatic axis of a toric IOL preoperatively, that is, before the surgery. If the appropriate device is used to mark the cornea, it would impact the outcome of surgery. This device also makes the patient and the surgeon comfortable to mark the cornea with accuracy and without hesitation. Video link: https://youtu.be/4MVM7HRwz70.

Microkera to mechronicles : Management of a free flap.

Background: In LASIK (laser in situ keratomileusis), a hinged corneal flap is made, which enables the flap to be lifted and the excimer laser to be applied to the stromal bed. If the hinge of the corneal flap detaches from the cornea, the flap is called a free cap. A free cap is a rare intra-operative complication of LASIK most commonly associated with the use of a microkeratome on corneas with flat keratometry, which predisposes to a small flap diameter. Free caps are preventable and treatable. Rarely does the complication lead to a severe or permanent decrease in visual acuity. Purpose: As free caps are avoidable, prevention is critical. Our video gives some tips and tricks on how to avoid a free flap and also focuses on how to manage a cut through a free flap. Synopsis: If a free cap is created, the surgeon must decide whether to continue with excimer laser ablation or to abort the procedure. When to abort: If the stromal bed is irregular, the flap is replaced without applying laser ablation. Without ablation, generally, there is no change in refractive error or significant loss of visual acuity. When to continue: If the stromal bed is regular and the cap is of normal thickness, the surgeon may proceed with ablation. To prevent desiccation, the free cap should be handled with caution and should be placed on a drop of balanced salt solution. The free cap should be placed epithelial facing up, along with a bandage contact lens. The endothelial cell pump mechanism typically allows the cap to re-adhere tightly. Highlights: Risk factors for a free cap are generally anatomic or mechanical. Especially in flat corneas, an appropriate ring and stop size should be chosen looking at the nomogram on the basis of the keratometry values. Deep orbits and deep-seated eyes should be looked for as PRK is a better option in such cases. Inadequate suction should be dealt with a lot of care, and once this is done, the vacuum should be stopped. Re-docking of the microkeratome with suction can be done again. Prior testing of the microkeratome and a good verbal anesthesia are a few more such important points to be pondered upon. This video gives us such tips and is a comprehensive video for a novice surgeon performing microkeratome LASIK. Video link: https://youtu.be/piU9nK6rbm4.

Ten commandments for biometry in tricky situations.

Background: Recently, the number of litigations on cataract surgeons has increased. Because of the increasing ambitions of surgeons and demands for a spectacle-free life, the incidence of unhappy patients is at an all-time high. To an ophthalmologist, the fruits of a good surgery are dependent largely on their skills. However, more importantly, the roots of good results of a surgery are laid by a perfect IOL (intraocular lens) power calculation. Inaccurate biometry is one of the major reasons for unhappy patients, especially in some challenging scenarios. Purpose: To hit the bull's eye, as far as target refraction is concerned, it is necessary to understand the benefits and limitations of currently available cutting-edge technology and formulae and apply them to the cataract surgery practice. The aim of the video is to familiarize modern-day ophthalmologists to these situations to achieve a perfect IOL power calculation. Synopsis: Using a step-by-step approach, we decoded biometry in special scenarios like poor cornea, ocular surface disorders, dry eyes, toric IOL calculation, cases with posterior corneal astigmatism, irregular corneas like keratoconus, pellucid marginal degeneration, post Lasik ectasia and penetrating keratoplasty. In this video we tried to address the solution to these special conditions and how to attain target refraction in such cases. A few more issues are addressed like biometry post retina surgery, very dense cataract where it is difficult to obtain axial length, and cases with extreme axial lengths. Highlights: In this case-based approach, with relevant example, we tried to provide solutions for biometry in tricky scenarios like poor cornea, biometry post refractive surgery, dense cataracts, and cataract post retinal surgery. On following these commandments, not only will the litigations stop but our patients will be happier as well. Online Video Link: https://youtu.be/dNXP2nDYUZo.

Hocus pocus: Breaking the curse of presbyopia.

Background: Research and awareness on refractive solutions for presbyopia, commonly known as the "Curse of the 40's," is essential as a large population in the world suffer from vision impairments. Population-based surveys have shown that one billion people in the world are in presbyopic age. Purpose: Many structural and physiological changes occur in the eye with the onset of presbyopia, including the decrease in amplitude of accommodation. At present, various static and dynamic techniques have been attempted to give presbyopes good vision at near-, intermediate-, and far-viewing distances. The aim of the video is to familiarize the modern-day ophthalmologists to these modalities. Synopsis: In this video, we tried to summarize the indications and contraindications of presbyopic laser. Preoperative investigations like dominance testing and micro monovision testing are described. The role of neuroadaptation and patient counselling is emphasized. Static techniques described in the video include spectacles, contact lenses, surgical options like corneal inlays and onlays, corneal laser ablation, conductive keratoplasty, corneal implant lenses, INTRACOR and IOLs. Dynamic presbyopia correction (accommodative) is always surgical. This is split into lenticular (accommodating IOLs, piggyback, lens refilling, lentotomy) and scleral treatment (laser-assisted presbyopia reversal and scleral expansion bands). Highlights: The types of corneal laser ablation, which is otherwise very confusing, is elaborated in a step-wise manner here. The difference in approach of PresbyLasik (Nidek), Presbyond (Zeiss) - Laser Blended Vision, PresbyMax (Schwind), INTRACOR (Technolas) are explained with examples. Each approach has its pros and cons. Our challenge as a surgeon is to identify the best combination for the patient. This video illustrates the treatment options which can help break the curse of presbyopia. Online Video Link: https://youtu.be/rTxMIqMrgaw.

Make in India: Normative data for automated perimetry.

BACKGROUND: The normative data set in authomated perimetry is predominantly of non-Indian origin and hence may not be an accurate basis for visual field analysis in Indian population.This video describes an attempt to create a native normative dataset for automated perimetry, which can then be fed in our machines and be used as the normative database. PURPOSE: To formulate normative data and to increase domain knowledge of normative values for automated perimetry in Indian population of different age groups. SYNOPSIS: Cross-sectional study conducted on patients receiving outpatient care in a span of 3 years, which included 6586 healthy normal patients (13172 eyes) with vision 6/6 unaided or after refractive correction. The patients were tested with 30-2 SITA FAST threshold algorithm on Humphrey Field Analyzer Model no: 745i. Normative data was calculated on basis of age group ranging from 19-75 years categorized to every decade. Normal values were formulated on basis of perimetry performed on normal patients. HIGHLIGHTS: Our work on creating a native normative dataset may add value as well as increase the accuracy of perimetry analysis in Indian eyes. ONLINE VIDEO LINK: https://youtu.be/jqgC2Tn7HIg.

Deciphering the enigma of astigmatism in cataract surgery.

Background: With about 87% of patients with cataracts having astigmatism, management of astigmatism in cataract surgery not only yields an improved unaided visual acuity and image quality but also higher patient satisfaction. The video will give a step-wise guide to cataract surgeons to manage astigmatism with cataracts. Purpose: To hit the bull's eye as far as target refraction is concerned, it is necessary to understand the benefits and limitations of currently available cutting-edge technology and formulae and apply them to the cataract surgery practice. The purpose of the video is to make sure that we have no surprises in our Toric intraocular lens (IOL) planning. Synopsis: After a brief introduction to available modalities for the treatment of astigmatism, a step-wise approach to diagnostics is discussed, which will include the role of corneal topography and aberrometers and their application to planning Toric IOLs. Appropriate planning, implementation, and execution in form of preoperative and intraoperative pearls of using Toric IOLs are shown in the video. This will be followed by troubleshooting and case-based discussions and future perspectives including the possible role of corneal biomechanics. Highlights: What this video adds new is the importance of topography, interpretation of Belin‒Ambrosio display map and the equivalent keratometry reading (EKR) map, aberrometry, and higher order aberration (HOA) analysis and role of biomechanics in Toric IOL planning. Video also highlights the importance of posterior corneal astigmatism and accurate axis marking. With a case-based approach and relevant examples, we are trying to decipher the enigma of astigmatism by giving a step-wise approach for the same. Online Video Link: https://youtu.be/5VuEY_6NdQA.

Patient-specific determination of change in ocular spherical aberration to improve near and intermediate visual acuity of presbyopic eyes.

The purpose was to determine the optimum negative spherical aberration induction required to improve near and intermediate visual acuity (VA) of presbyopic eyes. A total of 174 normal and diabetic (no retinopathy) presbyopic eyes (age ≥ 40 years) were measured with visual adaptive optics simulator (Voptica, Spain). First, baseline uncorrected VA and aberrations were measured. VA at 40 cm (near), 80 cm (intermediate) and distance was measured. Then, a negative spherical aberration (SA) was added to baseline ocular SA, and VA at all targets was reassessed after correction of distance refractive error. Clinically, baseline SA and root mean square of higher order aberrations were similar between the normal and diabetic presbyopic eyes. Baseline VA of the diabetic eyes at near and intermediate was better than the same of normal eyes (P = 0.001). After SA change, VA at near and intermediate of both normal and diabetic presbyopic eyes improved. However, fewer diabetic eyes needed higher SA change than normal eyes (P = 0.03). The corresponding trends with change in VA at near and intermediate were also similar between the normal and diabetic eyes. Patient-specific modulation of ocular SA to improve near and intermediate VA in a large cohort of eyes was successful in improving VA, sometimes even distance VA.

Repeatability of a Commercially Available Adaptive Optics Visual Simulator and Aberrometer in Normal and Keratoconic Eyes.

PURPOSE: To evaluate the repeatability of aberration measurement obtained by a Hartmann-Shack aberrometer combined with a visual adaptive optics simulator in normal and keratoconic eyes. METHODS: One hundred fifteen normal eyes and 92 eyes with grade I and II keratoconus, as per the Amsler-Krumeich classification, were included in the study. To evaluate the repeatability, three consecutive measurements of ocular aberrations were obtained by a single operator. Zernike analyses up to the 5th order for a pupil size of 4.5 mm were performed. Statistical analyses included the intraclass correlation coefficient (ICC) and within-subject standard deviation (SD). RESULTS: For intrasession repeatability, the ICC value for sphere and cylinder was 0.94 and 0.93 in normal eyes and 0.98 and 0.97 in keratoconic eyes, respectively. The ICC for root mean square of higher order aberrations (HOARMS) was 0.82 in normal and 0.98 in keratoconic eyes. For 3rd order aberrations (trefoil and coma), the ICC values were greater than 0.87 for normal eyes and greater than 0.92 for keratoconic eyes. The ICC for spherical aberration was 0.92 and 0.90 in normal and keratoconic eyes, respectively. CONCLUSIONS: Visual adaptive optics provided repeatable aberrometry data in both normal and keratoconic eyes. For most of the parameters, the repeatability in eyes with early keratoconus was somewhat better than that for normal eyes. The repeatability of the Zernike terms was acceptable for 3rd order (trefoil and coma) and spherical aberrations. Therefore, visual adaptive optics was a suitable tool to perform repeatable aberrometric measurements. [J Refract Surg. 2017;33(11):769-772.].