Retinal pigment epithelial tear after transpupillary thermotherapy for choroidal neovascularization

Photodynamic Therapy in Retinal Angiomatous Proliferation Stage I

PURPOSE

To report a case of photodynamic therapy (PDT) treatment in an 85-year-old patient with retinal angiomatous proliferation (RAP) stage I.

METHODS

According to Treatment of Age-Related Macular Degeneration with Photodynamic Therapy and Verteporfin in Photodynamic Therapy study guidelines, two sessions of PDT with verteporfin were performed, which was activated by a diode laser light at 690 nm.

RESULTS

The left eye was treated with PDT because of RAP stage I. Even in the early stage of RAP, PDT treatment did not alter the natural course of the disease. In particular, the lesion evolved towards stage III, being initially in stage I, with the final result of development of retinal pigment epithelial (RPE) tear after the second session of PDT treatment. CONCLUSIONS; Even in the early stage of RAP, PDT treatment did not alter the natural course of the disease, with the final result of RPE tear after the second session of PDT treatment.

Retinal Pigment Epithelium Tears: Risk Factors, Mechanism and Therapeutic Monitoring

Tears of the retinal pigment epithelium (RPE) are most commonly associated with vascularised RPE detachment due to age-related macular degeneration (AMD), and they usually involve a deleterious loss in visual acuity. Recent studies suggest an increase in RPE tear incidences since the introduction of anti-vascular endothelial growth factor (anti-VEGF) therapies as well as a temporal association between the tear event and the intravitreal injection. As the number of AMD patients and the number of administered anti-VEGF injections increase, both the challenge of RPE tear prevention and the treatment after RPE tear formation have become more important. At the same time, the evolution of retinal imaging has significantly contributed to a better understanding of RPE tear development in recent years. This review summarises the current knowledge on RPE tear development, predictive factors, and treatment strategies before and after RPE tear formation.

Quantification of retinal pigment epithelium tear area in age-related macular degeneration

PURPOSE

To compare different quantification tools based on confocal scanning laser ophthalmoscopy for assessment of retinal pigment epithelium (RPE) tear area size.

METHODS

Confocal scanning laser ophthalmoscopy fundus autofluorescence (FAF) and near-infrared reflectance (IR) images were retrospectively evaluated in 23 patients with RPE tear after intravitreal injection for pigment epithelium detachment due to exudative age-related macular degeneration at baseline and additionally in 11 patients after 5.1 ± 1.8 months of follow-up. Retinal pigment epithelium tear area was measured by three independent readers using three methods: manually on confocal scanning laser ophthalmoscopy FAF images, manually on confocal scanning laser ophthalmoscopy IR images, and using an FAF-based semiautomated software.

RESULTS

Confidence intervals were 0.08 and 0.12 for FAF, 0.11 and 0.09 for FAF-based semiautomated software, and 0.25 and 0.27 for IR for intraobserver (Reader 1) and interobserver agreements (Readers 1 and 2), respectively. The average values of the square errors of the quantification methods were 0.040 ± 0.033 mm (FAF), 0.035 ± 0.060 mm (software), and 0.187 ± 0.219 mm (IR). Mean area of RPE tears at baseline given as the average measurement of all 3 readers using FAF-based semiautomated software was 5.77 ± 4.62 mm (range, 0.13-14.74 mm). Follow-up measurements of unilobular RPE tears (8 patients) showed no change in lesion area size (0.14 ± 0.33 mm); in contrast, multilobular RPE tears (3 patients) showed a progression in lesion area size of 1.80 ± 0.74 mm.

CONCLUSION

Manual FAF-based and semiautomated FAF-based quantifications of RPE tear area are accurate and reproducible and superior to manual IR-based measurement. Retinal pigment epithelium tear area quantification is clinically relevant regarding further intravitreal treatment, particularly in multilobular RPE tears.

Long-term visual outcome of pigment epithelial tears in association with anti-VEGF therapy of pigment epithelial detachment in AMD

PURPOSE

Retinal pigment epithelium (RPE) tears may develop as a complication after anti-VEGF (vascular endothelial growth factor) treatment for pigment epithelial detachments (PEDs) in exudative age-related macular degeneration (AMD). This retrospective study analyses best-corrected visual acuity (BCVA) and foveal involvement after RPE tears that are associated with anti-VEGF therapy due to PED in exudative AMD.

METHODS

A total of 37 patients with RPE tears during anti-VEGF therapy (bevacizumab 12, ranibizumab 21 and pegaptanib 4 eyes) for progressive PED in AMD (PED with occult choroidal neovascularization 25 eyes and PED with retinal angiomatous proliferation 12 eyes) were included in this study. We analyzed BCVA and different morphologic aspects by means of appearance on fluorescein angiography and optical coherence tomography. Mean follow-up was 88 weeks.

RESULTS

RPE tears were diagnosed a mean of 56 days after the first injection. BCVA deteriorated after RPE tear and during follow-up significantly (P<0.001), with 53.2% of eyes being legally blind (WHO, world health organization) at 12 months. RPE-free foveal area, foveal wrinkling of the RPE, and fibrotic scar development were significantly associated with worse visual acuity.

DISCUSSION

RPE tears can be observed in 12-15% of treated eyes during anti-VEGF therapy for PED in exudative AMD. Owing to the close time relationship with the therapy, this complication must be taken into consideration. Visual prognosis is associated with a decrease in vision in the long term, often resulting in a severe visual disability. Relevant factors for a negative visual prognosis were the potential foveal involvement of the central RPE and morphologic fibrovascular transformation of the RPE tear.

Efficacy of transpupillary thermotherapy (TTT) in the treatment of occult subfoveal choroidal neovascularization in age-related macular degeneration

PURPOSE

To determine the efficacy of transpupillary thermotherapy (TTT) in the treatment of occult subfoveal choroidal neovascularization in patients with age-related macular degeneration (ARMD).

METHODS

We conducted a retrospective review of patients with ARMD treated with TTT from June, 1999 through July, 2000 at a retina referral practice. TTT was delivered through a slit-lamp using a modified diode laser at 810 nm wavelength and a spot size of 3 mm delivered at one location for a minimum of 60 seconds duration. Re-treatment was performed at 2-month intervals if indicated.

RESULTS

81 eyes of 77 patients were included in the study. Vision improved greater than one line Snellen in 18 eyes (22%), vision was stable within one line Snellen in 38 (47%), and worsened greater than one line Snellen in 25 (31%). Patients had a mean follow-up of 9 months. The average number of treatments was 1.37 (range 1 to 4). Pretreatment vision was less than or equal to 20/200 in 54% of eyes.

CONCLUSIONS

Transpupillary thermotherapy may stabilize visual acuity in a majority of patients with occult subfoveal choroidal neovascularization secondary to ARMD. Proof of therapeutic benefit is best determined by a randomized clinical trial that is currently underway (TTT4CNV).

Transpupillary thermotherapy (TTT) for age-related macular degeneration

PURPOSE

To review the results of transpupillary thermotherapy (TTT) on choroidal neovascular membranes associated with age-related macular degeneration (AMD).

MATERIALS AND METHODS

35 eyes of 35 patients with AMD and choroidal neovascularization and exudation were treated with TTT and had fundus photographs and fluorescein angiography (FA) before and at least six months after TTT. 28 eyes had predominantly occult lesions as seen on FA, while 7 demonstrated primarily classic lesions. All were treated with 650mw power or less using the 810 nm diode laser (3000 micron spot, duration of 60 seconds). Visual acuity, lesion size, and amount of subretinal fluid were determined by results of examination and review of photographs and fluorescein angiograms.

RESULTS

A 50% reduction in subretinal fluid was achieved in 67% of treated eyes overall, with stabilization of vision (less than three lines of visual acuity lost) in 86%. Complications from treatment were infrequent (9%) and involved hemorrhage noted in the region of treatment upon follow-up.

CONCLUSION

TTT promotes resolution of subretinal fluid and appears to stabilize visual acuity in patients with exudative AMD.

Transpupillary thermotherapy for age-related macular degeneration: Principles and techniques

Transpupillary thermotherapy (TTT) is a subthreshold, low irradiance, long exposure duration, large spot size, infrared diode laser protocol. Retinal temperature increases in TTT for choroidal neovascularization (CNV) are substantially lower than those in conventional short-pulse photocoagulation, but they are maintained for 60 seconds to achieve therapeutic results. Treatment power is adjusted for retinal lesion size, chorioretinal pigmentation, macular elevation and media clarity. TTT uses 810-nm diode laser infrared radiation, which has no significant retinal phototoxicity. A parfocal laser delivery system is required to assure uniformity of irradiance across large diameter treatment spots. Relative contraindications for TTT include dense subretinal hemorrhage, prior focal photocoagulation and serous RPE detachment. Adverse events are rare, and include decreased vision and retinal arteriole occlusion. Randomized, prospective multi-center trials are underway to compare the results of TTT for occult CNV in age-related macular degeneration to the natural history of the disorder. Imaging, electrophysiologic or thermometric techniques may ultimately provide intra-operative or post-operative monitoring to assure the adequacy of TTT for CNV, despite the absence of ophthalmoscopically visible lesions.

Subthreshold transpupillary thermotherapy for subfoveal occult choroidal neovascularization secondary to age-related macular degeneration

PURPOSE

To describe the long term outcome of patients with subfoveal, occult choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) treated with subthreshold transpupillary thermotherapy.

METHODS

82 eyes of 82 consecutive patients with subfoveal occult CNV secondary to AMD were treated with subthreshold transpupillary thermotherapy. Best corrected visual acuity, fundus photography, fluorescein and indocyanine green angiography were performed.

RESULTS

All patients have been followed for at least 24 months. At the final follow-up visit, 75.6% of patients had stable or improved visual acuity and 24.4% had worsened visual acuity. No overtreatment side effects were found.

CONCLUSION

Subthreshold transpupillary thermotherapy seems effective in stabilizing visual acuity in patients affected by occult, subfoveal CNV even on a long-term basis.

Transpupillary thermotherapy in chinese patients with choroidal neovascularization secondary to age-related macular degeneration: emphasis on the influence of power setting

PURPOSE

To perform a safety and efficacy study of transpupillary thermotherapy (TTT) in Chinese patients with choroidal neovascularization (CNV) secondary to age-related macular degeneration (ARMD).

METHODS

In a prospective study, patients with subfoveal or juxtafoveal CNV secondary to ARMD underwent TTT with fixed treatment and follow-up protocols. From August 2002 to December 2004, 26 patients (27 eyes) completed > or =6 months of follow-up and were included in this report.

RESULTS

Fourteen eyes (52%) had improved or stable visual acuity (loss of <3 lines) and 13 eyes (48%) had vision loss of > or =3 lines. The serial mean visual acuity initially decreased during follow-up, then stabilized by 6 months. In the subgroup of occult or minimally classic CNV (20 eyes), 13 eyes (65%) had improved or stable vision. The major complication of TTT included laser-related retinal pigment epithelium (RPE) atrophy in 10 eyes (37%). Six eyes had mild RPE atrophy, 4 eyes had severe RPE-choroid atrophy (macular burn). Analysis of possible risk factors for macular burn showed that 3 eyes had to have the power amplified due to nuclear sclerosis, and 1 pseudophakic eye had regular power.

CONCLUSIONS

TTT in Chinese ARMD patients with occult or minimally classic CNV, according to our protocol, prevented severe vision loss in the majority of patients, but power amplification due to medium lens opacity induced RPE atrophy or burn in some patients.

Retinal pigment epithelial tears after intravitreal bevacizumab injection for exudative age-related macular degeneration

We report a series of retinal pigment epithelial (RPE) tears after intravitreal bevacizumab therapy for choroidal neovascularization associated with age-related macular degeneration (ARMD). Retinal pigment epithelial tears were estimated to occur at an incidence of 1.6% in this patient population at our institution. Ophthalmologists should be aware of this rare but serious finding associated with exudative macular degeneration therapy.

Is transpupillary thermotherapy applicable to the treatment of age-related macular degeneration with pigment epithelial detachment?

The cause of pigment epithelial tears at the edge of a pigment epithelial detachment (PED) following transpupillary thermotherapy (TTT) in eyes with a PED associated with age-related macular degeneration has not been conclusively determined. We have treated two eyes that had a PED with TTT. A pigment epithelial tear developed in one eye but not in the other. Our findings suggest that pigment epithelial tears are probably related to the shape of the PED, and TTT should not be applied to a balloon-shaped PED.

Is transpupillary thermotherapy applicable to the treatment of age-related macular degeneration with pigment epithelial detachment?

The cause of pigment epithelial tears at the edge of a pigment epithelial detachment (PED) following transpupillary thermotherapy in eyes with associated age-related macular degeneration is unclear. We have treated 2 eyes which had a PED with TTT. Our findings suggest pigment epithelial tears are probably related to the shape of the PED and TTT should not applied to a balloon-shaped PED.

Low-Power Transpupillary Thermotherapy Combined with Intravitreal Triamcinolone Acetonide for Subfoveal Choroidal Neovascularization

PURPOSE

To examine transpupillary thermotherapy combined with intravitreal triamcinolone for treatment of subfoveal choroidal neovascularization.

METHODS

The clinical interventional, noncomparative, case series study included 14 patients (14 eyes) with choroidal neovascularization (age-related macular degeneration, n = 11; high myopia, n = 2; unknown reason, n = 1), who underwent transpupillary thermotherapy (75-150 mW, 60 s, 500-3,000 microm), followed by an intravitreal triamcinolone injection (10 mg). Follow-up was at least 6 months.

RESULTS

Visual acuity increased by 3 lines in 3 (21%) eyes at 3 months, and in 3 (21%) eyes at 6 months of follow-up. None of the patients experienced a visual acuity loss of 3 or more lines. At the 6-month follow-up, mean visual acuity was improved by 1.36 +/- 1.16 lines. Retreatment by transpupillary thermotherapy was performed for 3 (21%) eyes at 3 months, and for 1 (7%) eye at 6 months of follow-up.

CONCLUSIONS

Transpupillary thermotherapy combined with intravitreal triamcinolone may be a therapeutic option for choroidal neovascularization particularly if other treatment modalities are not available.

Retinal pigment epithelial detachment

Detachment of the retinal pigment epithelium is a prominent feature of many chorio-retinal disease processes, the most prevalent of which is age-related macular degeneration (AMD). Detachment of the retinal pigment epithelium may or may not be associated with choroidal neovascularization and may be caused by different types of pathogenesis, each associated with distinct angiographic features, natural course, visual prognosis, and response to treatment. The phrase "detachment of the retinal pigment epithelium" is used quite often, not always in the correct association and with no clear differentiation between its various types. It is important to identify the specific nature of detachment of the retinal pigment epithelium, and to establish an accurate diagnosis and treatment plan. Therefore, we present a review of the existing types of detachment of the retinal pigment epithelium with what we propose as being appropriate nomenclature and classification, and potential treatment recommendations.

Transpupillary Thermotherapy With Indocyanine Green Dye Enhancement for the Treatment of Occult Subfoveal Choroidal Neovascularization in Age-Related Macular Degeneration

BACKGROUND AND OBJECTIVES

Transpupillary thermotherapy (TTT) with indocyanine green (ICG) dye enhancement (TTT+) and TTT alone were compared for safety and effectiveness as a treatment of occult subfoveal choroidal neovascularization in age-related macular degeneration.

PATIENTS AND METHODS

Twenty-one patients were randomized to receive TTT (12 eyes) or TTT+ (9 eyes) and observed for at least 6 months. ETDRS visual acuity and fluorescein and ICG angiography were obtained every 3 months.

RESULTS

The median initial visual acuity was 20/80 in the TTT group and 20/100 in the TTT+ group. At 6 months, loss of less than 3 lines of visual acuity was present in 7 of 12 eyes (58%) in the TTT group and 5 of 9 eyes (56%) in the TTT+ group. At the final examination, there was no active choroidal neovascularization exudation in 6 of 12 eyes (50%) in the TTT group and 5 of 9 eyes (56%) in the TTT+ group. The median final visual acuity was 20/125 in the TTT group and 20/160 in the TTT+ group. Ocular or systemic complications were not encountered in either group.

CONCLUSION

TTT with ICG dye enhancement was as safe and effective as TTT alone in this study. However, modifications of treatment protocol would be needed to see whether there is any advantage to using ICG dye enhancement.

Retinal function following transpupillary thermotherapy for occult choroidal neovascularization in age-related macular degeneration: a short-term study by focal electroretinography

PURPOSE

To assess short-term changes in macular function after transpupillary thermotherapy (TTT) in patients with occult subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD), using focal electroretinography (FERG).

METHODS

Twenty-five patients with occult subfoveal CNV due to AMD were treated with TTT delivered using an infrared (810 nm) diode laser (spot size 3.0 mm, laser power 400-600 mW, duration 60 seconds). All patients were clinically evaluated before, 1 and 6 weeks after treatment. Snellen visual acuity (VA) was measured at each visit. Fluorescein angiography (FA) was performed at baseline and 6 weeks after TTT. Focal ERGs were recorded in all patients immediately before and 1 week after TTT in response to an 18-degree diameter, 41 Hz flickering spot (630 nm) centred on the fovea, presented on a steady background in Maxwellian view. A subgroup of 12 patients was also re-tested by FERG at 6-weeks post-TTT.

RESULTS

No significant changes in mean FERG amplitude and phase were observed across the different recording sessions before and after TTT. One week after TTT, four patients had significant (> 2 SD from baseline variability) increases in FERG amplitude and/or phase advances, one had a decrease in amplitude and four had phase delays, compared to baseline. The remaining 15 patients had stable FERGs. Six weeks after TTT, four patients had significant increases in FERG amplitude and/or phase advances, four had decreases in amplitude and/or phase delays, and four had stable FERGs, compared to baseline. Improvement in FERG parameters after TTT was always associated with an improvement in VA and a decrease in exudation. Patients with post-TTT FERG deterioration had stable or deteriorated clinical pictures. At either 1 or 6 weeks post-TTT, the FERG amplitude increase was inversely correlated (p < 0.05) with the baseline FERG amplitude and VA.

CONCLUSIONS

Three major conclusions can be drawn: in a short-term follow-up, TTT was not found to be associated with significant changes in macular function; FERG improvement was associated with VA improvement, and the increase in FERG amplitude was greatest in patients with the worst baseline acuity.

Low power vs standard power transpupillary thermotherapy in patients with age-related macular degeneration and subfoveal choroidal neovascularization ineligible for photodynamic therapy

AIM

To assess the effect of standard power vs low power transpupillary thermotherapy (TTT) in patients with active subfoveal choroidal neovascularization secondary to age-related macular degeneration ineligible for photodynamic therapy (PDT) by original treatment of age-related macular degeneration with photodynamic therapy (TAP) study group recommendations.

METHODS

Retrospective review of 79 patients with active predominantly occult subfoveal choroidal neovascularization or predominantly classic subfoveal choroidal neovascularization but Snellen visual acuity <20/200. All patients were treated with TTT administered via a Mainster wide field fundus contact lens with a retinal power/diameter coefficient of 248 mW/mm in the standard power (n=27) and 181 mW/mm in the low power group (n=52). The primary outcome was stabilization (<1 Snellen line change) or improvement (two or more Snellen lines) in visual acuity. Clinical and fluorescein angiographic resolution of overlying exudation was documented.

RESULTS

At 24 month follow-up, 17 patients (63%) in the standard power and 36 patients (69%) in the low power group achieved stable or improved vision. Improved vision (mean three lines) was observed in 22% of the standard power and 23% of the low power group. Overlying exudation was reduced clinically with minimal or no leakage on fluorescein angiogram in 85% of standard power and 90% of low power group. Subgroup analysis in the low power group demonstrated a visual benefit in patients with subfoveal lesions, which had any classic component.

CONCLUSIONS

Low power TTT is as effective as standard power in stabilizing or improving vision and reducing overlying exudation in patients with active subfoveal choroidal neovascularization ineligible for PDT.

Transpupillary thermotherapy for occult subfoveal choroidal neovascularization: a 1-year, prospective randomized pilot study

PURPOSE

To evaluate the 1-year effect of transpupillary thermotherapy (TTT) on occult choroidal neovascularization membranes (CNV).

METHODS

In this prospective, randomized, controlled pilot study of 28 patients with occult or minimally classic (< 10%) neovascularization membranes with a diameter less than 4500 microm, 19 patients were treated with TTT, while nine received sham treatment. Outcome measures were membrane diameter, visual acuity and reading ability.

RESULTS

The median age of patients randomized to TTT was 78 years (range 24 years); that of patients randomized to sham was 79 years (range 9 years). There was no difference regarding membrane diameter at baseline between the two groups; the median membrane diameters were 3400 microm (range 2400 microm) in the TTT group and 3200 microm (range 2300 microm) in the sham group (p = 0.639). Visual acuity (VA) was similar, with a median of 0.2 (minimum-maximum 0.08-0.5) in the TTT group and a median of 0.16 (min-max 0.10-0.32) in the sham group. A total of 21 patients were followed for 1 year, 13 in the TTT group (2.7 treatments/patient) and eight in the sham group. Membrane diameter increased in both groups, by a median of 350 microm (range 1600 microm) in the TTT group and 800 microm (range 1700 microm) in the sham group (p = 0.414), respectively, and there was a loss in VA of > or = 15 letters in 5/13 patients (38%) in the TTT group compared with 2/8 patients (25%) in the sham group (p = 0.266). Reading ability deteriorated equally over time in both groups. Seven patients were lost to follow-up due to reluctance to continue in the study (n = 4) or development of a classical component > 50% (n = 3) requiring photodynamic therapy (PDT).

CONCLUSION

The results from this randomized, prospective pilot study of TTT for occult CNV did not indicate that TTT has a beneficial effect on visual outcome 1 year after treatment compared with the visual outcome that results from the natural course of the disease. The small study size limits statistical power and results from large control studies are needed.

[Transpupillary thermotherapy for occult choroidal neovascularizations]

PURPOSE

This contribution describes the results of transpupillary thermotherapy (TTT) for age-related exudative macular degeneration (AMD) with regression.

PATIENTS AND METHODS

In exudative AMD with occult choroidal neovascularization (CNV), transpupillary thermotherapy (TTT) was performed using a diode laser (Iridex) in unselected patients. Before therapy and 1, 3, and 6 months after the initial treatment the patients were examined clinically. Additionally threshold testing in the 10 degrees field (Humphrey) and fluorescein angiographies were documented at all check-ups.

RESULTS

With respect to vision, differences in the slope of the regression lines between small, medium, and large CNV were significant (p<0.001). The slope of the regressions lines was significant except for small CNV. Regarding the 10 degrees field (Humphrey), there were no statistical differences in the slope of the regression lines (p=0.867).

CONCLUSIONS

Transpupillary thermotherapy with small CNV did not show a statistically significant decrease of VA. Thus, in clinical terms early treatment of occult CNV with TTT seems to be able to prevent a further loss of visual acuity.

Transpupillary thermotherapy for the treatment of subfoveal choroidal neovascularization associated with age-related macular degeneration

OBJECTIVE

To evaluate the efficacy of transpupillary thermotherapy (TTT) for the treatment of choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD).

DESIGN

Prospective, non-randomized, non-masked, case-selected series.

METHODS

All patients with subfoveal CNV due to AMD and initial visual acuity (VA) between 6/9 and 6/60 were offered the opportunity to undergo TTT. Recruited subjects were treated using a diode laser (810 nm) with a beam size of 1.2-3.0 mm and power settings of 460-1200 mW. Treatment was applied for 60 seconds in a subthreshold manner.

MAIN OUTCOME MEASURES

Differences in VA and changes in the angiographic appearance of CNV.

RESULTS

Thirty-one occult/predominantly occult and five classic/predominantly classic membranes were treated with TTT and were followed-up for a mean of 6.0 +/- 1.2 months. Following an average of 1.5 +/- 0.7 (range 1-4) laser sessions, VA remained stable ( -1 to +1 Snellen line) in 24 (66.7%) eyes, improved by > 1 line in two (5.6%) eyes and decreased significantly (> or = 2 Snellen lines) in 10 (27.8%) eyes. Angiographically confirmed closure of CNV was detected in 22 (61.1%) patients. Membranes persisted in 11 (30.6%) eyes and recurred in three (8.3%) eyes. There was no association between reduction, elimination or persistence of angiographic leakage of CNV and change in VA after treatment (p = 0.347).

CONCLUSIONS

Transpupillary thermotherapy may be effective at preserving vision and reducing CNV leakage in a number of patients with exudative AMD. Further studies are required to compare TTT with the natural course of subfoveal CNV and alternative treatment options.

Transpupillary thermotherapy for treatment of exudative age-related macular degeneration in Japanese patients

PURPOSE

To report the therapeutic outcome of transpupillary thermotherapy (TTT) for subfoveal choroidal neovascularizarion (CNV) in brown retina using a diode-laser with the setting of lower energy level compared to the previous studies on light-pigmented Caucasian patients.

METHODS

A total of 19 subfoveal CNVs in 18 patients were treated with TTT. The power of diode-laser was set 160 mW for 1.2 mm beam, 270 mW for 2.0 mm beam, and 400 mW for 3.0 mm beam, and the laser was delivered for 1 min through a slit-lamp mounted-delivery system. Patients were followed up for a mean of 8.8 months (4-12 months). Visual acuity and the fundus change as judged by funduscopic examination and simultaneous fluorescein and indocyanine green angiography were evaluated. Visual acuity was measured by a Japanese standard Landolt visual acuity chart and converted to logarithm of the minimal angle resolution (log MAR) visual acuity for statistical analysis. Improvement or decline in vision was defined as change of more than 0.2 in log MAR visual acuity.

RESULTS

In eyes with minimally classic or occult only CNV, visual acuity improved in two eyes (18%) stabilized in seven eyes (64%) and worsened in two eyes (18%). In eyes with predominantly classic CNV, visual acuity improved in two eyes (25%), stabilized in four eyes (50%) and worsened in two eyes (25%). In all, 15 (84%) eyes of all studied subjects had improvement in exudation. Two (11%) and one (5%) eye(s) were noted to have a significant post-treatment haemorrhage and retinal pigment epithelial tear, respectively.

CONCLUSION

In patients with brown retinal colour, the treatment outcome of TTT was comparable to that of light-pigmented Caucasian patients with approximately half the laser power energy. Further randomized control studies are warranted.

Review Article. New treatments in age-related macular degeneration

Age-related macular degeneration (AMD) is the leading cause of legal blindness in individuals 50 years and older in the developed world. Choroidal neovascularization (CNV) in exudative AMD is responsible for the majority of severe vision loss. Until recently, laser photocoagulation was the only well-established and widely accepted treatment for CNV. However, it is beneficial only for a small subset of patients, has a high rate of CNV persistence and recurrence and results in iatrogenic, collateral damage to the overlying retina. These issues make it difficult to recommend in the case of subfoveal lesions. Consequently, numerous experimental therapeutic interventions are under investigation with the common objective of destroying the CNV but leaving the foveal neurosensory retina intact. Treatment modalities can be grouped into five major categories: photodynamic therapy; radiotherapy; transpupillary thermotherapy; anti-angiogenic and angiostatic agents; and surgical intervention. The present review aims to explain the rationale behind these new treatments, analyse the evidence for their safety and efficacy, determine their stage of development and indicate in which patients they are potentially useful.

Transpupillary thermotherapy threshold parameters: funduscopic, angiographic, and histologic findings in pigmented and nonpigmented rabbits

PURPOSE

To evaluate the effect of pigmentation on threshold fluence levels, needed to produce visible and angiographic lesions, of transpupillary thermotherapy (TTT) in rabbits.

METHODS

Six pigmented and nine nonpigmented rabbits underwent TTT with an 810-nm diode laser coupled to a slit-lamp biomicroscope using a spot size of 2 or 3 mm. The power ranged from 80 to 200 mW with 1 to 3 minutes of laser exposure for pigmented rabbits and 750 to 1800 mW with 1 minute of exposure for albino rabbits. These parameters were also evaluated after compression of the globe using the contact lens to induce blanching of the optic nerve head. After the experiment, the eyes were enucleated under deep anesthesia, and the animals were killed immediately.

RESULTS

In pigmented rabbits, the threshold fluence with the 2-mm spot size was 229 J/cm2 without compression and 153 J/cm2 with compression. With the 3-mm spot size, the threshold decreased from 200 to 150 mW as the duration of exposure lengthened (2 or 3 minutes), increasing the fluence from 170 to 382 J/cm2. In nonpigmented rabbits, the threshold fluence with the 2-mm spot size was 2,865 J/cm2 without compression and 2,674 J/cm2 with compression. With the 3-mm spot size, the threshold fluence of 1,528 J/cm2 was not affected by compression. Histopathologic studies showed transretinal damage at the lowest levels necessary to achieve angiographic evidence of a treatment lesion or a barely visible funduscopic lesion at the time of treatment.

CONCLUSIONS

Nonpigmented rabbits required more than a 12-fold increase in total TTT fluence compared with pigmented rabbits with the 2-mm spot size and a ninefold increase with the 3-mm spot size. Inner and outer retinal damage was seen histopathologically at these levels.

Transpupillary thermotherapy threshold parameters: effect of indocyanine green pretreatment

PURPOSE

To evaluate the effect of combined treatment with systemic indocyanine green (ICG) on threshold fluence levels of transpupillary thermotherapy (TTT) in rabbits.

METHODS

Four pigmented rabbits and 13 nonpigmented rabbits were studied. TTT was performed on normal rabbit choriocapillaris using an 810-nm diode laser via slit-lamp biomicroscope delivery through a Goldmann macular lens. Laser spot size, power, and duration of laser exposure were varied to achieve a range of TTT fluences for threshold testing in both albino and pigmented rabbit fundi. Intravenous ICG pretreatment at doses of 0.41 to 10 mg/kg was initiated at varying times before TTT treatment. After the experiment, the eyes were enucleated under deep anesthesia, the animals were killed, and the eyes were prepared for light microscopy.

RESULTS

When intravenous ICG pretreatment was employed, there was a dose-dependent decrease in the TTT fluence threshold as compared with known threshold values. At threshold fluences, histopathologic sections revealed damage to all layers of the retina in addition to choriocapillaris damage.

CONCLUSION

Intravenous ICG pretreatment can be used to lower the TTT threshold fluence and irradiance required to create angiographically visible lesions in the normal rabbit choriocapillaris. Damage was seen in all layers of the retina and choriocapillaris at threshold levels when TTT was used alone or in combination with ICG pretreatment.