1. Posterior segment
complications of refractive
surgery

2. Refractive eye surgery
Is any eye surgery used to improve the refractive
state of the eye and decrease or eliminate
dependency on glasses or contact lenses. This can
include various methods of surgical remodeling of
the cornea or the lens. Successful refractive eye
surgery can reduce or cure common vision
disorders such as myopia, hyperopia and
astigmatism, as well as degenerative disorders
like keratoconus.

3. CORNEAL REFRACTIVE
SURGERY

4. The most common methods today use excimer
lasers to reshape the curvature of the cornea
Clearly, LASIK is an anterior segment
procedure, but it could have posterior segment
consequences. Although
rare,
posterior
complications following LASIK have been
documented, and including retinal tears, retinal
detachments, retinal hemorrhages, macular holes,
and choroidal neovascular membranes

5. The relationship between the LASIK
procedure and vitreoretinal complications is
difficult to establish, since such complications
occur with a higher incidence in patients with
high myopia, being the majority of patients
undergoing refractive surgery.
There is also fact that vitreoretinal
complications observed share a common
pathophysiology, which is posterior vitreous
detachment (PVD)

6. The suction and the increase in pressure
induced by the suction ring used to fixate the eye
while the microkeratome creates the flap could
elongate the eye along the anteroposterior axis,
which in turn could cause a contraction in the
horizontal axis. This combination of events may
push the lens anteriorly and cause vitreoretinal
traction at the vitreous base and the posterior pole
and facilitate PVD.

7. Cutting the flap with a femtosecond laser rather
than a microkeratome requires lower suction but
longer duration. LASIK with the femtosecond
laser has been reported with rhegmatogenous
RD, macular hemorrhage and. Epi-LASIK, which
also requires relatively longer suction durations,
has been associated with optic neuropathy.

8. Retinal detachments
It is interesting that retinal detachments
occurred at approximately 9 months after LASIK.
Therefore, corneal refractive surgery probably
does not increase the rate of retinal detachment
any more than if the patient had not undergone
surgery.

9. When planning surgical treatment of RD following
LASIK, certain factors should be considered. Post-LASIK
patients may be dissatisfied with the myopic shift
following encircling scleral buckling, and alternative
techniques (such as segmental scleral buckling, PPV or
pneumatic retinopexy) may be considered. If scleral
buckling is performed, the vitreoretinal surgeon should
understand that the patient may desire future LASIK
enhancement if retinal reattachment is achieved and if
good central vision returns. Conjunctival scarring and
anterior placement of an encircling buckling element may
prevent proper placement of a microkeratome following
successful scleral buckling.

10. If PPV is chosen to treat RD, the surgeon should
attempt to protect the corneal flap during surgery
to avoid flap dislocation

11. Macular hemorrhage

12. Theoretically, when a break in Bruch’s membrane
occurs, it allows the progression of the
neovascularization under the retina. The increase
in intraocular pressure (IOP) to levels over 60 mm
Hg during suction with the microkeratome suction
ring up to 4 mm posterior to the limbus may exert
posterior traction. This mechanism may open the
gap in Bruch’s membrane even more. In patients
with high myopia and lacquer cracks, LASIK
should be considered contraindicated and some
other method of refractive surgery offered (i.e.
phakic IOL

13. Macular hole
Macular hole has reported to occurs 6 m- 1y after
LASIK for myopia.

14. LENS-BASED REFRACTIVE
SURGERY

15. Phakic IOL:
Angle supported
Iris supported
Posterior chamber lens (precrystalline)
Clear lens extraction with IOL implantation:
Myopia
Hypermetropia
Astigmatism
Prespyopia
Anisometropia

16. Posterior segment complications of
lens refractive surgery

17. Perforated globe
Supra-choroidal haemorrhage
Dropped nucleus
Cystoid macular oedema
Macular phototoxicity
Macular infarction
Retinal detachment
Postoperative endophthalmitis

18. Perforated globe
Accidental perforation of the globe is an
acknowledged complication of peribulbar,
retrobulbar anaesthesia. High myopia is a strong
risk factor for globe perforation in peribulbar
anaesthesia.
Signs and symptoms of perforation include intense
ocular pain, sudden loss of vision and hypotony.
Interestingly, in one review, about 50% of the
patients had no immediate symptoms or signs of
perforation

19. This injury could be avoided by minimizing
the number of injections, use of blunt needle,
noting negative aspiration before injection,
inspection of aspirate for blood or vitreous fluid
and to wiggle the syringe before injecting, to
ensure that the globe is not pierced by the needle
(although not universally accepted). It is also
recommended to discontinue the injection if
corneal edema or resistance to injection occur.

20. Supra-choroidal haemorrhage

21. Risk factors: older age, taking at least one
cardiovascular medication, glaucoma, elevated
preoperative intraocular pressure, the lack of
orbital compression after LA , PC rupture, HTN,
axial myopia, retrobulber injections, coughing
and valsalva.

22. Intra-operative SCH:
Signs:





Shallow AC
^ IOP
Dark red reflex
Iris prolapse
Extrusion of introcular contents.

23. Management:
Prophylactic:

Avoid sudden hypotony

Preplaced sutures
Immediate:

Wound closure

Formation of AC by BSS

Lowering BP

Sedation

Remove speculum and bridle sutures

Posterior sclerotomy
Subseqent:

Steroid

U/S

Surgery

24. Post-operative SCH
Presentations:

Sudden pain

Loss of vision

Shallow AC

^IOP
Management:
Wound intact: medical to control IOP
Wound not intact: surgical closure
When to drain:

Persistant flat AC

Kissing choroidale

Uncontrolled IOP for one week

Persistant Choroidal detachment

25. Dropped nucleus

26. Management: Vitrectomy

27. Cystoid macular oedema

28. CME is the result of accumulation of fluid in
the central macula in the outer plexiform layer
with the formation of cystoid spaces.
The term “cystoid macular edema” (CME)
applies when there is evidence by biomicroscopy,
fluorescein angiography (FA), and/or optical
coherence
tomography
(OCT)
of
fluid
accumulation into multiple cyst-like spaces within
the macula.

30. Potentially toxic substances including PGs
normaly contained in the anterior segment may
diffuse posteriorly to the macula
Risk factors:
Surgical approach
Diabetic and HTN Patients
Iris incaceration in the wound
A ruptured posterior capsule
Retained lens fragment

32.  Prophylaxis: NSAIDS
 Substantial subgroups of patients with refractory
macular oedema show interest in other treatment
modalities, including pars plana vitrectomy, medical
therapy with protein kinase C inhibitors , intravitreal
injection of corticosteroids or a sustained release
intravitreal corticosteroid implant

33. Macular phototoxicity

34. Operating microscope light induced foveal damage is a
well recognised occurrence following ocular surgery
PM is the result of a photochemical and thermal lesion
of the retina due to ultraviolet radiation from the operating
microscope, characterized by affecting the outermost
retinal layers. It is related to the intensity, exposure time
and wavelength of the light source, with blue and UV light
(wavelength below 300-350 nm) being the most damaging
for the eye

35. At the clinical level, it is characterized by a yellowish lesion at
the foveal level, a window defect in FA and a central or paracentral scotoma which diminishes with time. The initial yellowish
lesions are subsequently replaced by a dotting of the RPE or even
a lamellar hole.
These patients may notice a pericentral scotoma,
metamorphopsia or slight/moderate vision loss between one and
four hours after exposure. The scotoma may diminish after a few
months and the patient usually recovers part of the lost eyesight.

37. Precautions against phototoxic lesions:
The use of ultraviolet filters on the microscope, air in the AC to
defocus the light from the retina.
Minimizing the time and power of coaxial illumination from the
microscope
Keeping the patient's body temperature low to reduce the
temperature within the eye, irrigation solutions may be cooled
relative to room temperature.
Lowering the inspired oxygen concentration for the patient during
the procedure as it has been shown that an increase in inspired
oxygen markedly enhances retinal phototoxicity.
Stop photosensitising treatment particularly for underlying potential
photosensitising systemic conditions before surgery and taking
appropriate surgical precautions (Manzouri et al., 2002).

38. Postoperative endophthalmitis

39. Postoperative acute endophthalmitis is a
devastating complication after intraocular surgery
and can be seen as increased pain, redness, lid
edema, anterior chamber reaction, corneal haze,
vitreous haze, frank exudates in the vitreous or
absent red reflex. This condition needs to be
treated as an emergency with maximum medical
therapy and may sometimes require vitrectomy

40. Risk factors :
Increased operative time, low experienced
surgeon.
Posterior capsule rupture/vitreous loss.
Retained lens fragments.
Inadequate sterilization of the operative field.
Contamination of surgical instruments.
Inadequate wounds eg, leaky

41. Once infection occurs, damage to ocular tissues is believed to occur
due to direct effects of bacterial replication as well as initiation of a
fulminant cascade of inflammatory mediators. Endotoxins and other
bacterial products appear to cause direct cellular injury while
eliciting cytokines that attract neutrophils, which enhance the
inflammatory effect. Thus, recent efforts in controlling the damaging
effects of endophthalmitis in experimental models have focused on
identifying not only appropriate antibiotics for control of the
infectious agent but also on anti-inflammatory agents that might
disrupt the immunologic events that occur after infection

42. Macular infarction

43. With accidental entry of aminoglycosides after
subconj Injection from the site of the wound so
better avoided.

44. Retinal detachment

45. Risk factors:
Lattice degeneration
High myopia
Rupture posterior capsule
Vitreous loss

46. Final recommendations for refractive
surgeons to consider before performing
surgery in myopic patients

47. •Inform the patient that retinal detachments can
occur. If after refractive surgery he presents
symptoms suggesting retinal traction, break, or
detachment, explain the symptoms and see the
patient as soon as possible.
•When performing refractive lens exchange, use an
IOL with a low rate of PCO.
•Carefully examine the periphery of the fundus to
detect any breaks or lattice degeneration that may
require follow-up or laser treatment.

48. Thank you