Transpupillary Thermotherapy for classic subfoveal choroidal neovascularization : a case report

AUTHORS A O HASSAN FRCS, FRCOphth, FWACS *O ODERINLO FRCS, DRCOphth O OKONKWO FRCS DRCOphth F OLUYADI FWACS FMCOphth A O OGUNRO FWACS FMCOphth S A OKE DO (WACS) M ULAIKERE FWACS FMCOphth

INSTITUITION

EYE FOUNDATION HOSPITAL 27B Isaac John Street Ikeja GRA Lagos

* author for correspondence

Key words: Transpupillary thermotherapy, Age Related Macular Degeneration, Subfoveal choroidal neovascularisation, Fundus Flourescein Angiography.

SUMMARY

Aim: To report a case of a successful treatment of a classic subfoveal choroidal neovascularisation with a Transpupillary Thermotherapy protocol. Case report: a sixty seven year old pensioner who presented with six months history of reduced vison in both eyes,he is a known glaucoma patient previously diagnosed with primary open angle glaucoma. After anterior and posterior segment examination with fundus flourescein angiography a diagnosis of a classic subfoveal choroidal neovascularisation secondary to Age related macular degeneration OS with bilateral cataracts and primary open angle glaucoma OU was made. Complete resolution of the choroidal neovascular membrane was achieved with Transpupillary thermotherapy. INTRODUCTION Transpupillary thermotherapy (TTT) is a low irradiance large spot size prolonged exposure (long pulse), infrared laser phtotocoagulation protocol 1.presently being investigated for use in treatment of choroidal neovascular membranes Its main advantages are that lasers in the infrared range are less absorbed by the xanthophyll pigment and thus damage to the nerve fiber layer is minimized, compared to the argon laser the infrared diode is also poorly absorbed by haemoglobin allowing an improved ability to treat through preretina and subretina hemorrhage 2. The relatively larger spot size also enables treatment of larger lesions with a single burn. TTT has only been recently put to use in our Hospital ,we present a case report of one of the first patients diagnosed with a classic subfoveal choroidal neovascularization that was treated with TTT.

CASE REPORT Mr J A O a sixty seven year old pensioner presented to our hospital on the 9th of December 2004 with complaints of reduced vision in both eyes over a period of 6 months, he is a known spectacle wearer and had earlier been diagnosed with Chronic Primary Open Angle Glaucoma and is also a known hypertensive patient. He had bilateral trabeculectomies in may 2002

Examination on the same day revealed visual acuities of OD hand movements only and OS counting fingers only improving with a pinhole to 6/60. facial appearance papillary light reactions and extraocular muscle movements were normal in both eyes. Both conjunctiva showed cystic filtering blebs with intraocular pressures of 12mmHg OD and 16mmHg OS by applanation tonometry. gonioscopy revealed open angles of Shaffer grade 3-4 in both eyes. There were definite posterior subcapsular cataracts in both eyes but worse on the right. Fundus examination revealed bilateral intermediate and large macular drusen, with macular subretina hemorrhages OS .with cup to disc ratio of 0.8 in both eyes An assessment of :1 bilateral age related macular degeneration, ? exudative OS 2 posterior subcapsular cataracts OU worse OD 3 bilateral primary open angle glaucoma

He had a fundus flourescein angiography in both eyes on 16th of December 2004 which revealed classic subfoveal choroidal neovascularization in the left eye (figure 1a and 1b)the right eye had no choroidal neovascular lesion. Subsequently he had TTT laser treatment to his left eye on the same day the angiography was done, parameters used were spot size 3.00mm power setting of 500 mW and duration of 60s . he also had a right extracapsular cataract surgery with a posterior chamber implant on 25th of january 2005 . His last clinic visit was on the 25th of may 2005 visual acuities in both eyes of counting fingers OD and 6/60 OS a refraction revealed OD -0.50DS/-4.00dcyl x 100 = 6/36 OS + 0.50DS/-1.50dcyl x 800 =6/36 add + 3.00DS = N36 Anterior segement findings were normal with the exception of R pseudophakia and early posterior subcapsular cataracts. both discs were pale and cupped with CDR of 0.8 OU and normal intraocular pressures. He is presently taking G betoptic 0.5% 12 hourly OU and tabs antioxidants 1 bd. he feels much better and can even read large prints, he is also able to make his way around better and really appreciates his ocular care with us.

DISCUSSION

Subfoveal choroidal neovascularization still remains a management challenge to ophthalmologist, medicare guidelines in the United States of America presently favours phtotodynamic therapy for predominantly classic subfoveal neovascularization 3 , however in our environment this treatment modality is very expensive, each vial of visudyne cost £850:00 which is approximately =N= 212,500:00 , this cost excludes the amount needed for fundus flourescein angiography and the surgeons fees, it should also be noted that repeated treatment sessions are needed and that not all subfoveal neovascular lesions respond well to this treatment modality. Hence the advent of multiple researches into the use of TTT in the management of these lesions is of great interest. TTT has been evaluated for use in both occult and classic choroidal neovascularization and encouraging results have been reported 4,5,6 In our hospital TTT is done with the IRIS Medical Oculight SLx infrared (810nm) solid state laser with Tri-mode using a slit lamp delivery method and a Goldmanns 3 mirror lens,our prefared parameters of 60s duration ,3mm spot size and power variation from 300mW to 700mW is usually varied depending on the location of the lesion and patients tolerability. Mr J A O particularly responded well and figure 2 shows a complete resolution of the subfoveal lesion at 2 months after treatment with his glaucoma control still maintained. We believe that with several ongoing clinical trials on the clinical uses of TTT for choroidal neovascular membranes, the truth about its efficacy will be known , our case report serves to add a positive word to the ongoing evaluation.

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6 Singer M A , Willerson Jr D. Transpupillary Thermotherapy in Treatment of occult and classic choroidal neovascularization. Presentation. The Vitreous Society 18th Annual Meeting, Cancun Mexico January 7 – 11 , 2001. Figure 1a

Figure 1 b Figure 2