1. Consultant Rounds
Ophthalmology Block 10A

2. General Data 27/M L.T. Baguio City Chief Complaint
Blurring of Vision, OU

3. History of Present Illness
11 yrs PTC
Progressive BOV, bilateral, solitary symptom
Corrective lenses improved vision
9 years PTC
Repeated corrections were done over time
Consult at BGHkeratoconus
7 months PTC
Consulted at SLU hospital
Referred to PGH for co-management
11 years PTC Patient noted progressive BOV OU, with no other ocular symptoms. Corrective lens was used with improvement of vision. However, due to progressiveness of the BOV, patient had multiple attempts in obtaining optimum spectacle correction.
9 years PTC Consulted BGH, he was diagnosed with keratoconus, no medication was given, and patient was not advised RGP use.
7 months PTC He consulted at SLU hospital, still due to BOV, he was then referred to PGH for management.

4. ROS
(-) tearing
(-) redness
(-) discharges
(-) photopsias
(-) floaters
(-) metmorphopsias
Medical History
(-) previous surgeries, hospitalizations
(-) Asthma, Goiter, cancer, DM, HPN
Family History
(+) DM type 2
(-)Similar condition in the family Asthma, Goiter, cancer, DM, HPN
P/S: occasional alcohol drinker, non-smoker, denies illicit drug use

5. Physical Exam Stable vital signs No gross deformities or abnormalities
Otherwise unremarkable

6. Ophthalmologic EvaluationOD
20/200
PH: 20/70 OS
20/100 +1
PH: 20/50
VISUAL ACUITY

7. OU: 2-3 mm (+)EBRTL; (-)RAPD
Gross Eye Exam
Coning of the cornea
OU: 2-3 mm (+)EBRTL; (-)RAPD
(+) Munson sign L>R
(+) Rizzuti’s Sign OS

8. Full EOM on duction and version, (-) limitations

9. Tonometry Fundoscopy OD Soft OS Soft
OD (+) ROR, CM, DDB, AVR: 2:3, (-) H/E
OS (+) ROR, CM, DDB, AVR: 2:3, (-) H/E

10. SLIT LAMP
(+) Fleisher’s Ring, OS
Striae, OU
(+) Vogt’ s

11. DIFFERENTIAL DIAGNOSES?

12. Error of Refraction Rule in (-) other occular symptoms BOV Rule out
Progressive BOV
(+) gross corneal deformity
Repeated Refractions

13. Vogt's lines, Fleischer's ring
Keratoconus
Rule in
Progressive BOV
Cone shape cornea
Munson’s sign
Vogt's lines, Fleischer's ring
Rule out
Cannot rule out

14. Pellucid Marginal Degeneration
Rule in
Progressive BOV
Ectatic cornea
Astigmatism
Rule out
Cannot rule out
Cy eto lang alam ko sa PMD differential: This is supposedly a close differential to KC. The difference essentially is that this is rarer than KC and the point of corneal protrusion is above the area of maximal corneal thinning. In the case of PMD, the point of maximal thinning is at the inferior cornea.

15. Working Diagnosis
Keratoconus

16. Computer-assisted Videokeratography
Diagnostics
Careful refraction
Keratometry
Computer-assisted Videokeratography

17. Slit lamp biomicroscopy Rigid gas permeable contact lens application
Biopsy

18. This will be my part. Bukas ko na gawin
What is Keratoconus?

19. Ectatic corneal disease Noninflammatory
Keratoconus
Progressive
Bilateral
Ectatic corneal disease
Noninflammatory
Keratoconus (KC) is a progressive, noninflammatory, bilateral (but usually asymmetrical) ectatic corneal disease, characterized by paraxial stromal thinning and weakening that leads to corneal surface distortion. Visual loss occurs primarily from irregular astigmatism and myopia, and secondarily from corneal scarring. Protrusion usually but not exclusively affects the axial and inferonasal cornea. Examples of keratoconus are shown in the images below.
Paraxial stromal thinning
Corneal Surface Distortion

20. Irregular astigmatism
myopia
Corneal scarring
Visual Loss
Visual loss occurs primarily from irregular astigmatism and myopia, and secondarily from corneal scarring. Protrusion usually but not exclusively affects the axial and inferonasal cornea. Examples of keratoconus are shown in the images

21. Puberty until 3rd-4th decades of life
Epidemiology
US: cases/100, 000 pop
Equal incidence
Puberty until 3rd-4th decades of life
Frequency: Reported prevalence in the general population varies ( cases per 100,000 population), perhaps with differences in diagnostic criteria. It is commonly an isolated ocular condition but sometimes coexists with other ocular and systemic diseases. ommonly recognized ocular associations include vernal keratoconjunctivitis, retinitis pigmentosa, and Leber congenital amaurosis; systemic putative associations include many of the connective tissue disorders (eg, Ehlers-Danlos and Marfan syndromes), mitral valve prolapse, atopic dermatitis, and Down syndrome.
Keratoconus typically presents at puberty and progresses until the third and fourth decades of life, although it can occur or progress at any age. Keratoconus progresses at various rates but tends to progress more rapidly in young patients.

22. Rigid Contact lens wear
Risk Factors
Atopy
Rigid Contact lens wear
Vigorous Eye rubbing
Keratoconus
Particular risk factors include atopic history, especially ocular allergies, and perhaps either or both rigid contact lens (CL) wear, and vigorous eye rubbing.
Most keratoconus cases appear spontaneously, although approximately 14% of cases present with evidence of genetic transmission.
approximately 14% of cases present with evidence of genetic transmission

23. Pathophysiology
epithelial basement membrane fragmentation and scarring
breaks in the anterior limiting lamina
axial stromal thinning and scarring
All layers of the cornea are believed to be affected by keratoconus, although characteristic structural changes include epithelial basement membrane fragmentation and scarring and breaks in the anterior limiting lamina (ie, Bowman membrane), with axial stromal thinning and scarring. Deposition of iron in the basal epithelial cells forms the Fleischer ring. Breaks in and folds close to the Descemet membrane result in acute hydrops rarely and striae commonly, respectively.

24. Research has discovered that corneas with keratoconus have been exposed to a number of factors that can produce reactive oxygen species (i.e., free radicals). These include ultraviolet light, atopy, mechanical eye rubbing, and poorly fitted contact lenses. They propose that susceptible corneas exhibit an inability to process reactive oxygen species because they lack the necessary protective enzymes (e.g., ALDH3 and superoxide dismutase). The reactive oxygen species result in an accumulation of toxic byproducts such as MDA and peroxynitrites that can damage corneal proteins and trigger a cascade of events that disrupt the cornea's cellular structure and function

25. This can result in corneal thinning, scarring, and apoptosis

26. Clinical Presentiation
BOV
Photophobia
Glare
Monocular Diplopia

27. Disease Progression
Progressive Loss of VA
Scissor’s Reflex
Charleux oil drop reflex
Disease progression is manifested by a significant loss of visual acuity which cannot be compensated for with spectacles. A scissors reflex (Caused by having both hyperopic and myopic reflexes) during retinoscopy is a very early sign. The Charleux oil drops that is observed by backlighting the mydriatic pupil also poses a warning sign. Retroillumination shows the irregular cornea and shadow at base of cone.

28. Fleisher’s Ring
Vogt’s Striae
Prominent Corneal Nerves
In moderate and advance cases of keratoconus, a hemosiderin arc or circle line, commonly known as Fleischer's ring, is frequently seen around the cone base. 1,6,13,14 This line has been suggested to be an accumulation of iron deposits from the tear film onto the cornea as a result of severe corneal curvature changes induced by the disease and/or due to modification of the normal epithelial slide process
Another characteristic sign is the presence of Vogt's striae ( Figure 7 ), which are fine vertical lines produced by compression of Descemet's membrane, which tend to disappear when physical pressure is exerted on the cornea digitally or by gas permeable contact lens wear.
The increased visibility of corneal nerves (and observation of superficial and deep corneal opacities are also common signs, which can be present at different severity stages of the disease

29. Munson’s sign
Rizzuti’s sign
Corneal Hydrops
Munson's sign, (\ a V-shape deformation of the lower eyelid when the eye is in downward position, and Rizzuti's sign, a bright reflection of the nasal area of the limbus when light is directed to the temporal limbal area, are signs frequently observed in advanced stages.
Breaks in Descemet's membrane have been described in severe keratoconus, causing acute stromal oedema, known as Hydrops, sudden vision loss and significant pain.

30. Morphologic Classification
Nipple
Oval
Keratoglobus
Nipple- the cone has a diameter ≤ 5mm, round morphology and is located in the central or paracentral cornea, more commonly in the infero-nasal corneal quadrant. Correction with contact lenses is normally relatively easy.
Oval- The cone has a diameter > 5mm and a paracentral to peripheral location, more commonly in the infero-temporal corneal quadrant. Contact lens correction is more difficult.
Keratoglobus - The cone is located throughout 75% of the cornea. Contact lens correction is a difficult challenge, except in very limited cases.
In recent years, some practitioners have
abandoned the nipple-oval-globus
classification due to the widespread use of
corneal topographers.

31. Amsler’s Classification
Stage 1
Fruste or subclinical form; diagnosed by corneal topography; ~ 6/6VA achievable with spectacle correction.
Stage 2
Early form; mild corneal thinning; corneal scarring absent.
Stage 3
Moderate form; corneal scarring and opacities absent; Vogt's striae; Fleischer's ring; <6/6VA with spectacle correction, but ~ 6/6VA with contact lens correction; irregular astigmatism between 2.00–8.00 D; significant corneal thinning.
Stage 4
Severe form; corneal steepening >55.00 D; corneal scarring, <6/7.5VA with contact lens correction; severe corneal thinning and Munson's sign.
Severe form; corneal steepening >55.00 D; corneal scarring, <6/7.5VA with contact lens correction; severe corneal thinning and Munson's sign.

32. Index-Based Systems for Keratoconus Detection
Author
Index
Cut-off Value
Description
Rabinowitz/Mc Donnel
K Value
47.2
Diagnosis is performed based on the central keratometry and the inferior–superior asymmetry in keratometric power
I-S Value
1.4
Maeda/Klyce
KPI
0.23
KPI is derived from eight quantitative videokeratography indexes. KCI% is derived from KPI and other four indexes.
KCI% 0%
Smolek/Klyce
KSI
0.25
Keratoconus detection and the level of severity is assessed using an artificial intelligence system

33. Schwiegerling/Greivenkamp Z3 0.00233
Author
Index
Cut-off Value
Description
Schwiegerling/Greivenkamp Z3
Diagnosis is performed based in videokeratoscopic height data decomposed into orthogonal Zernike polynomials.
Rabinowitz/Rasheed
KISA%
100%
Diagnosis is derived from K value, I-S value, AST and SRAX.
Mc Mahon et al.
KSS
0.5
Diagnosis is performed based on slit-lamp findings, corneal topography, corneal power and higher order first corneal surface wavefront root mean square error.
Mahmoud et al.
CLMI
>0.45
Diagnosis based in detecting the presence or absence of keratoconic patterns and determining the location and magnitude of the curvature of the cone.

34. Management

35. Eyeglasses/soft contact lenses
Rigid gas permeable (RGP) contact lenses
Intracorneal rings
Corneal cross-linking
Corneal transplant

36. Eyeglasses/soft contact lenses
Early stage KC
Mild astigmatism/myopia
Have a limited role in improving vision
the front surface of the lens assumes the same irregular surface as the cornea without trapping a fluid reservoir so the effective refracting surface is no improvement over the original corneal surface

37. Rigid gas permeable (RGP) contact lenses
primary option for correcting KC vision
masks the underlying irregular cornea
functions as the new refractive surface

38. Intracorneal rings
Semi-circular rings inserted into the mid layer of the cornea
Flatten the cornea  change the shape and location of the cone
Eliminates some or all of the irregularities caused by keratoconus
Glasses or contact lenses may still be needed

39. Corneal cross-linking
Not a cure but prevents progression of KC
Glasses or contact lenses may still be needed
custom-made riboflavin drops saturate the cornea, then activated by ultraviolet light. This process has been shown in laboratory and clinical studies to increase the amount of collagen cross-linking in the cornea and strengthen the cornea

40. Corneal transplant
May be indicated
Dangerously thin cornea
VA not achieved by contact lens
steepening of the cornea
scarring
lens intolerance
warranted when the cornea becomes dangerously thin or when sufficient visual acuity to meet the individual’s needs can no longer be achieved by contact lenses due to steepening of the cornea, scaring or lens intolerance. Lens intolerance occurs when the steepened, irregular cornea can no longer be fitted with a contact lens, or the patient cannot tolerate the lens.

41. The Bioethics of the Cornea

42. Corneal Transplantation
Who should receive corneas?
Distributive Justice
Limited supply
Need to answer: How are we to fairly distribute this scarce resource?

43. Possible Answers
Maximum benefit
Equal Access

44. Race, Sex, Income, location,etc
Equal Access
Objective Criteria
Age
Length of time waiting
Etc
Selection Free of Bias
Race, Sex, Income, location,etc
Medical
Social

45. Probability of transplant successs Extent of medical need
Maximum Benefit
Probability of transplant successs
Extent of medical need
Lifespan/organ function
Pre-existing psychiatric conditions

46. Arguments Against “Maximum Benefit”
1.) It is difficult to predict medical success
2.) From 1., it’s a slippery slope down
3.) Using criteria like remaining life span or transplant success devalues life

47. The Law and the Cornea
Governed by RA 7785 with reference to RA 7170 aka Organ Donation Act of 1991
Basically, corneas like other organs are donated in the manner of “movable property”
If consent from donor lacking, donation can be executed by spouse, child, parents, siblings or guardians
Corneas can be received by hospitals, eye banks, educational institutions or specified individuals

48. How to increase cornea supply?
Education
Incentive
Mandated Choice
Presumed Consent
Condemned Prisoners

49. Thank you.
Hard light bathed them-a whole nation of eyeless men, Dark bipeds not aware how they were maimed. A long Process, clearly, a slow curse, Drained through centuries, left them thus.
-CS Lewis, The Country of the Blind