BEYOND LASER AND SURGERY-ALTERNATIVE
TREATMENTS FOR DIABETIC RETINOPATHY
Richard J. Madonna, OD, MA, FAAO
Associate Professor
SUNY State College of Optometry
New York, NY
rmadonna@sunyopt.edu
Abstract: Despite laser and surgical treatment for diabetic retinopathy, many lose
significant amounts of vision to the disease. This course discusses alternatives to laser
and surgery that may prevent, retard, or reverse this potentially devastating condition.
I.
STATEMENT OF THE PROBLEM-WHY ARE NEW TREATMENTS
NEEDED?
A. Incidence and Prevalence of Diabetic Retinopathy
B. Efforts to prevent diabetic retinopathy
C. Effectiveness of laser treatment
1) Proliferative diabetic retinopathy (PDR)
2) Clinically significant macular edema (CSME)
D. Effectiveness of surgical treatment
1) Vitrectomy in PDR
2) Repair of tractional retinal detachment
E. Despite our best efforts, a tremendous number of persons still lose vision to
diabetic retinopathy
II.
ANGIOGENESIS
A. Physiological angiogenesis
1) Process
2) Example-wound healing
B. Abnormal angiogenesis
1) The cancer experience
(a) Role of angiogenesis in tumor growth
(b) Turning on the “angiogenic switch”
2) Angiogenesis in proliferative eye diseases
(a) Hypoxia
(b) The interplay of growth factors
III.
GROWTH FACTORS
A. VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF)
1) Functions
(a) Increase vascular permeability
(b) Angiogenesis
2) Upregulation in hypoxia
3) Control of angiogenesis
B. OTHER GROWTH FACTORS
1) Fibroblast Growth Factor (FGF)
2) Platelet-derived Growth Factor (PDGF)
3) Hepatocyte Growth Factor (HGF)
4) Relationship of other growth factors to VEGF
IV.
NATURALLY OCCURING ANTI-ANGIOGENIC AGENTS
A. Types
1) Endostatin
2) Angiostatin
3) Pigment Epithelium-Derived Factor (PEDF)
B. Relationship of naturally occurring anti-angiogenic agents with growth factors
such as VEGF
V.
ANTI-ANGIOGENIC THERAPY IN THE EYE
A. Previous attempts in AMD
B. Need for prolonged therapy in the eye-chronicity of eye disease
1) Oral administration
(a) Systemic toxicity
(b) Interference with normal physiological functions
2) Intra-vitreal injection
(i)
Overcomes the blood-retinal barrier
(ii)
Limited by short half-life of drugs
3) Gene transfer
(a) Process
(b) Suitability for treatment of the eye
(i)
Immune privileged status of the eye
(ii)
Relative isolation of the eye
(iii)
Using the non-treated second eye as a control
(iv)
Ease of ocular examination
VI.
INTRAVITREAL STEROID TREATMENT
A. Adjunctive treatment of proliferative disease
1) Vitrectomy
2) Neovascular glaucoma
B. To treat macular edema
1) Intravitreal fluocinolone acetonide implant (Retisert)
2) Intravitreal triamcinolone acetonide injection
VII. OTHER TREATMENTS
A. Aldose reductase inhibitors
1) Review of the sorbitol pathway
2) Sorbinil Retinopathy Trial (SRT)-1990
3) New aldose reductase inhibitors
B. Aminoguanidine
1) Nitric oxide synthase (NOS) inhibitor
2) Shown to reduce retinopathy
C. Aspirin
1) Does it have a role in the treatment of DR?
2) How does it work?