Dr. Boral Subhendu Kumar, B09751, Dr. Debdulal Chakraborty, Dr. Das Arnab, Dr. Samar Kumar Basak
Introduction: In K-Pro-treated eyes, several common obstacles like obtaining adequate surgical exposure, visualisation, and hemeostasis were noted over last decade.1 Eyes with permanent keratoprosthesis present unique challenges for posterior segment surgery. Managing vitreoretina through the small optical cylinder is a real obstacle. Even in the era of suture less small gauze vitrectomy with wide angle visualisation system, this obstacle can be partially overcome. Vitreo retinal complications in eyes with permanent K-Pro1, described in the literature, are retro prosthesis membrane (RPM), retinal detachment(RD), epiretinal membrane (ERM), vitreous opacities or debris and endophthalmitis. 2,3
Purpose : To assess the vitreoretinal complications, outcomes and intra & post operative challenging factors after implantation of permanent kerato prosthesis.
Method : A retrospective review and analysis of 102 cases of permanent keratoprosthesis, implanted by a single surgeon over a 7-year period (2010-16) and posterior segment complications were managed by a single surgeon at the same institution. 23G vitrectomy done in all along with associated procedures. Silicone oil (5000 cst) injection done only in eyes with retinal detachment (RD) with or without proliferative vitreo retinopathy [PVR] and persistent hypotony cases.
Challenging intra and post-operative factors identified are difficulty in visualisation through the small optical cylinder, difficulty in vitreous base excision, recurrent intra-operative hypotony and bleeding and post-operative chronic hypotony (more than 1 month).
Results :
Total number of Permanent Keratoprosthesis done in last seven years : 102 (86 Boston Keratoprosthesis1 and 16 Aurokeratoprosthesis). Out of 102 K pro patients, 12 interventions done in 10 eyes who developed vitreoretinal problems after a mean period of 10.33 ± 7.11 month of K-Pro.
Indications for vitreoretinal interventions were as follows:
-Rhegmatogenous Retinal Detachment with PVR – 2/102 K pro1
-Hemorrhagic RD-1/102,
-Post vitrectomy RD – 1/102,
-Persistent hypotony with choroidal detachment – 2/102,
-Epiretinal membrane- 1/102
-Sterile vitritis with choroidal with macular folds-1/102
-Retro prosthetic Membrane (RPM) – 1/102
-Severely vascularised RPM with vitreous haemorrhage – 1/102
-Endophthalmitis with vitreous abscess (culture negative) – 1/102 and
-Silicone oil removal and reinjection -1/102
Mean post op BCVA 0.95 ± 0.48 Log MAR.
Mean follow up was 9.25 ± 7.92 months.
Challenging factors were evaluated and analysed by performing Fisher’s exact test. Challenging factors were
- Difficulty in visualisation (8 in 12 cases, p value<0.01),
- Difficulty in vitreous base excision (6/12, p value<0.01),
- Intra operative recurrent hypotony with choroidal formation (1/12, p>0.05) due to leakage around cannulas because of thin sclera,
- Recurrent bleed (1/12, p>0.05),
- Post-operative chronic hypotony(6/12, p value<0.01).
Discussion: The permanent Keratoprosthesis has essential value for visual restoration in patients with corneal blindness. But vitreoretinal complications remain a significant cause of ocular morbidity.
Kiang L et al combined two procedures; i.e pars planavitrectomy and K Pro together as they provide valuable information on the patient’s visual potential and remove potentially inflammatory material. 2
But Harissi-Dagher M et al concluded that pars planavitrectomy through the Boston K Pro is a viable approach for vitreoretinal disease repair, visual rehabilitation remains poor. 4
Ray S et al demonstrated trans eyelid modified vitreoretinal surgical techniques can be effectively and safely used to treat posterior segment complications in patients with K Pro devices with severe ocular surface diseases. Retro-K Pro membranes and other vitreous opacities were most amenable to treatment. Retinal complication posed a special challenge. 1
Chan CC et al showed Boston type I K Pro implantation in combination with pars planavitrectomy and intra ocular silicone oil fill in 13 eyes can improve vision in most prephthisical eyes with hypotony with simultaneous structural improvement. 5
We have intervened 12 times in 10 eyes for vitreoretinal complications after 102 successful cases of permanent keratoprosthesis. Vitrectomy through keratoprosthesis itself is a challenge. In our study, the most common indications for vitreoretinal intervention in eyes with permanent keratoprosthesis were retinal detachment (4/12, two primary RD, one haemorrhage RD and one post vitrectomy RD), followed by persistent hypotony with choroidal detachment (2/12) and RPM (2/12). Although cases with RPM, treated with YAG laser capsulotomy, were not included in our study.
We evaluated challenging factors in such cases of vitreoretinal complications in eyes with permanent keratoprosthesis. Statistically significant challenging factors were difficulty in visualisation (8 in 12 cases, p value < 0.01), difficulty in vitreous base dissection (6/12, p value <0.01) and postoperative chronic hypotony (6/12, p value <0.01). Other factors like recurrent intra operative hypotony and recurrent bleed were not significant. (Fisher’s exact test).
Conclusion : Eyes with permanent keratoprosthesis offer challenges for vitreo retinal surgeons and with the back ground knowledge of it’s inherent limiting factors, vitreo retinal challenges can be managed successfully. Significant challenging factors identified in our study are difficulty in visualisation, difficulty in vitreous base excision and post-operative chronic hypotony.
References :
- Ray S, Khan B F, Dohlman CH, D’Amico DJ. Management of vitreoretinal complications in eyes with Permanent Keratoprosthesis. Arch Ophthalmol.2002;120(5):559-66.
- Kiang L, Sippel K C, Starr C E, Ciralsky J, Rosenblatt M I, Radcliffe N M, D’Amico DJ, Szlla’rd Kiss. Vitreoretinal Surgery in the setting of Permanent Keratoprosthesis. Arch Ophthalmol.2012;130(4):487-92.
- Modjtahedi BS, Eliott D. Vitreoretinal complications of Boston Keratoprosthesis. Seminars in Ophthalmology. 2014; 29(10):338-48.
- Harissi-Dagher M, Durr GM, Biernacki K, Sebag M, Rheaume M-A. Pars planavitrectomy through the Boston Keratoprosthesis type1. Eye (Lond). 2013; 27(6):767-9.
- Chan CC, Holland EJ, Sawyer WI, Neff KD, Petersen MR, Riemann CD. Boston type1 keratoprosthesis combined with silicone oil for treatment in prephthisical eyes. Cornea.2011;30(10):1105-9.
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