This document summarizes corneal and refractive surgery procedures presented by various speakers. It discusses keratoplasty techniques like penetrating keratoplasty and lamellar keratoplasty. It also covers endothelial keratoplasty, limbal stem cell grafting, keratoprostheses, and refractive procedures like LASIK to correct refractive errors. Post-operative complications of various procedures and their management are also summarized.
A surgical procedure featuring a partial thickness scleral flap that creates a fistula between AC and subconjunctival space for filtration of aqueous and creation of conjunctival bleb in an effort to lower IOP
A surgical procedure featuring a partial thickness scleral flap that creates a fistula between AC and subconjunctival space for filtration of aqueous and creation of conjunctival bleb in an effort to lower IOP
Basic overview of phaco dynamics along with all the Newer phacoemulsification techniques available in current practice - a video-assisted the presentation
A lecture on the current techniques (mainly surgical) for the correction of Presbyopia. This includes information on static and dynamic surgical and non surgical approaches.
Basic overview of phaco dynamics along with all the Newer phacoemulsification techniques available in current practice - a video-assisted the presentation
A lecture on the current techniques (mainly surgical) for the correction of Presbyopia. This includes information on static and dynamic surgical and non surgical approaches.
LASIK or Lasik (laser-assisted in situ keratomileusis), commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hyperopia, and an actual cure for astigmatism, since it is in the cornea. LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye's cornea in order to improve visual acuity. For most people, LASIK provides a long-lasting alternative to eyeglasses or contact lenses.
The planning and analysis of corneal reshaping techniques such as LASIK have been standardized by the American National Standards Institute, an approach based on the Alpins method of astigmatism analysis. The FDA website on LASIK states,
"Before undergoing a refractive procedure, you should carefully weigh the risks and benefits based on your own personal value system, and try to avoid being influenced by friends that have had the procedure or doctors encouraging you to do so."
The procedure involves creating a thin flap on the eye, folding it to enable remodeling of the tissue beneath with a laser and repositioning the flap.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
Acute scrotum is a general term referring to an emergency condition affecting the contents or the wall of the scrotum.
There are a number of conditions that present acutely, predominantly with pain and/or swelling
A careful and detailed history and examination, and in some cases, investigations allow differentiation between these diagnoses. A prompt diagnosis is essential as the patient may require urgent surgical intervention
Testicular torsion refers to twisting of the spermatic cord, causing ischaemia of the testicle.
Testicular torsion results from inadequate fixation of the testis to the tunica vaginalis producing ischemia from reduced arterial inflow and venous outflow obstruction.
The prevalence of testicular torsion in adult patients hospitalized with acute scrotal pain is approximately 25 to 50 percent
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
3. KERATOPLASTY
• Replacement of diseased host corneal tissue by healthy donor
cornea
• Partial thickness or full thickness
4. INDICATIONS
• Optical keratoplasty- improve vision. They include keratoconus,
scarring, corneal dystrophies, pseudophakic bullous keratopathy and
corneal degeneration
• Tectonic graft -restore or preserve corneal integrity in eyes
• Therapeutic corneal transplantation – in eyes unresponsive to
antimicrobial therapy
• Cosmetic grafting- to improve the appearance of the eye
6. DONOR TISSUE
• Removed within 12-24 hours of death
• Age-match donors and recipients
• Stored in coordinating eye banks for pre-release evaluation
• Preserved in hypothermic storage(7-10 days) and organ
culture(4 wks)
7. CONTRAINDICATIONS TO TISSUE
DONATION
• Death from unknown causes
• Certain systemic infections
• Prior high risk behavior for HIV and hepatitis
• Sex with someone who has engaged in high risk behavior(last 12months)
• Infectious and possibly infectious disease of the CNS
• Receipt of a transplanted organ
• Receipt of human pituitary-derived GH
• Brain or spinal surgery before 1992
• Most hematological malignancies
• Ocular disease
8. RECIPIENT PROGNOSTIC FACTORS
• Severe stromal vascularization
• Abnormalities of the eyelids
• Conjunctival inflammation
• Tear film dysfunction
• Anterior synechiae
• Uncontrolled glaucoma
• Uveitis
9. PENETRATING KERATOPLASTY
• Key surgical points
Graft size 7.5mm
Donor button >0.25mm larger than host site
Preparation should precede excision of host tissue
Manual/automated trephination is used
Secured with interrupted or continuous suture techniques
20. SUPERFICIAL LAMELLAR KERATOPLASTY
• Partial-thickness excision of the corneal epithelium and stroma
• Endothelium and deep stroma are left behind
Indication
• Opacification of the superficial 1/3 corneal stroma
• Marginal corneal thinning or infiltration
• Localized thinning or descemetocoele
21. DEEP ANTERIOR LAMELLAR KERATOPLASTY
(DALK)
• Corneal tissue is removes almost to the level
of Descemet membrane
• Decreased risk of rejection-endothelium is
not transplanted
Indications
• Disease involving anterior 95% of cornel
thickness with absence of breaks/scars in
Descemet’s membrane
• Chronic inflammatory disease
22. DEEP ANTERIOR LAMELLAR KERATOPLASTY
Advantages
• No risk of endothelial
rejection
• Less astigmatism and
stronger globe
• Increased availability of graft
material
Disadvantages
• Difficult and time consuming
• Interface haze may limit best
final VA
23. DEEP ANTERIOR LAMELLAR KERATOPLASTY
• Post operative management
Similar to penetrating keratoplasty except lower intensity topical
steroids are needed and sutures are removed after 6 months
24. ENDOTHELIAL KERATOPLASTY
• Removal only of diseased endothelium along with Descemet
membrane through corneoscleral or corneal incision.
• Folded donor tissue introduced through the same small(2.8-
5.0mm) incision
• DSAEK- uses an automated microkeratome to prepare door
tissue .Small posterior stromal thickness transplanted along
with DM and endothelium
• DMEK-only the DM and endothelium transplanted
• Indications - endothelial disease
25. ENDOTHELIAL KERATOPLASTY
Advantages
• Little refractive change and
more intact globe
• Faster visual rehabilitation
• Suturing is minimized
Disadvantages
• Significant learning
curve
• Specialized equipment
required
• Endothelial rejection
26. LIMBAL STEM GRAFTING
Techniques include:
• Transplantation of a limbal area of limited
size
• Complete limbal transplantation
• Ex vivo expansion by culture with
subsequent transplantation
27. KERATOPROSTHESES
• Artificial corneal implants use in
patients unsuitable for
keratoplasty
• Odontokeratoprostheses-
patient’s own tooth root and
alveolar bone and covered with a
buccal mucous membrane graft
• Surgery is difficult and time
consuming, done in 2 stages 2-4
months apart
29. KERATOPROSTHESES
Indications
• Bilateral blindness- severe but
inactive anterior segment
disease
• VA of counting finger or less in
better eye
• Intact optic nerve and retinal
function
• High patient motivation
Complications
• Glaucoma
• Retroprosthesis membrane
formation
• Tilting or extrusion
• Endophthalmitis
30. KERATOPROSTHESES
Results
• Approx. 80% of patients achieve VA between counting fingers
and 6/12
• Poor outcome associated with pre-existing optic nerve or
retinal dysfunction
32. CORRECTION OF MYOPIA
• Surface ablation procedures- correct low-moderate degrees of
myopia
• Laser in situ keratomileusis (LASIK)- moderate-high myopia
depending on corneal thickness
• Refractive lenticule extraction- correction of myopia and
myopic astigmatism
• Clear lens exchange- very good visual result but small risk of
complications of cataract surgery
34. CORRECTION OF MYOPIA
• Phakic posterior chamber implant( ICL)- inserted behind the iris
and in front of the lens, supported in the ciliary sulcus
Material derived from collagen with a power of -3D to -20.50D
Complications include uveitis, pupillary block, endothelial cell
loss, cataract formation and retinal detachment
• Radial keratotomy
35. CORRECTION OF MYOPIA
Anterior chamber iris claw implant
with anterior
iris attachment at 3 and 9 o’clock
inferior subluxation
with resultant inferior endothelial
decompensation –
note also an iridectomy to prevent pupillary
block
emplacement of a posterior chamber
phakic implant
between the iris and anterior lens
surface
36. CORRECTION OF HYPERMETROPIA
• Surface ablation procedures- low degrees
• LASIK – up to 4D
• Conductive keratoplasty (CK)- application of
radiofrequency energy to the corneal stroma
,thermally induced stromal shrinkage is
accompanied by increase in central corneal
curvature
• Laser thermal keratoplasty- holmium laser can
correct low hyperopia
• Clear lens extraction
• Phakic lens implants
37. CORRECTION OF ASTIGMATISM
• Limbal relaxing incisions/ arcuate keratotomy-making paired
arcuate incisions on opposite sides of cornea in the axis of the
correcting plus cylinder
• PRK and LASEK – up to 3D
• LASIK- up to 5D
• Lens surgery- toric intraocular implant
• Conductive keratoplasty
38. Arcuate
Keratotomies ; toric intraocular implant in site
markings incorporated in the lens (arrows)
facilitate correct
orientation
39. CORRECTION OF PRESBYOPIA
• Lens extraction- to treat cataract of
refractive purposes
Include :
• Clear lens exchange(CLE)
• Refractive lens exchange(RLE)
• Presbyopic lens exchange(PreLEx)
41. LASER REFRACTIVE PROCEDURES
Laser In Situ Keratomileusis
• The excimer lase is used to reshape corneal stroma exposed by
the creation of a superficial flap
• Myopia corrected by central ablative flattening
• Hyperopia by ablation of the periphery so that the center
becomes steeper
• Generally used to treat higher refractive errors:
Hypermetropia- up to 4D
Astigmatism –up to 5D
Myopia –up to 12D
44. LASIK
Technique
• Suction ring centered on the cornea is applied to the globe-
raises IOP
• Ring stabilizes the eye and provides the guide track for a
mechanical microkeratome
• The flap is reflected and the bed reshaped then flap
repositioning
46. LASIK
Postoperative complications
• Tear instability
• Wrinkling, distortion or dislocation of the flap
• Subepithelial haze
• Persistent epithelial defects
• Epithelial ingrowth under the flap
• Diffuse lamellar keratitis
• Bacterial keratitis
• Corneal ectasia
47. SURFACE ABLATION PROCEDURES
• Photorefractive keratectomy(PRK) employs excimer laser ablation to reshape
the cornea
• Corrects myopia- up to 6D , astigmatism- around 3D and low-moderate
hyperopia
• Main disadvantage as compared to LASIK- lower degrees of refractive error
correctable and slower epithelial healing
• Lower risk of serious complications than in LASIK
• Suitable for patients renders ineligible for LASIK due to low corneal
thickness
• Other indications include epithelial basement membrane disease, prior
corneal transplantation or radial keratotomy and large pupil size
48. SURFACE ABLATION PROCEDURES
Technique
• Corneal epithelium is removed using a sponge, an automated
brush and alcohol
• Ablation of the Bowman’s layer and anterior stroma, taking 30-
20 sec
• Epithelium heals within 48- 72 hrs. bandage contact lens is
used to minimized discomfort
51. SURFACE ABLATION TECHNIQUES
Variations of PRK
• LASEK- Laser Epithelial Keratomileusis or Laser –assisted
subepithelial keratectomy
• Epi-LASIK-Epipolis or epithelial LASIK
• Modified PRK
• ASLA OR ASA- Advanced surface ablation
• Trans-PRK- transepithelial PRK
52. REFRACTIVE LENTICULE EXTRACTION
• ReLex is a relatively long technique that uses a femtosecond
laser to cut a lens-shaped piece of corneal tissue with the
intact cornea
• Then removed via a LASIK-style flap or using a minimally
invasive 4mm incision
• Advantages include:
Less marked biochemical and neurological corneal disturbance
than LASIK
Surface disturbance is minimal in comparison to surface
ablation procedures