Twenty-one Chinese patients (19 female and 2 male) aged between15-58 (mean 37±11) years old were included in this study. The presenting symptoms were usually floaters, blur vision and even lost vision of one eye for 1 to 6 months. One patient had no symptoms and was found retinal vascular abnormality and hemorrhage during health examination. The initial mean decimal BCVA was 0.55±0.38 (LP ~ 1.5). All the patients were FFA proved IRVAN bilaterally at the first visit except 4 patients who had one eye with VH (2 eyes) and/or PVR (2 eyes). Two eyes with VH were proved with typical IRVAN by FFA after pars plana vitrectomy (PPV). Two PVR eyes did not have FFA examination, although one of the eyes accepted PPV. Two patients were lost follow-up including the patient with a NVG eye. The follow-up time of the rest 19 patients 38 eyes was 6-120 (70±36.4) months. The demographic information and clinical features are summarized in Table 2.
No eye in this series cases agreed with Stage 1. Eighteen eyes (18/42) with FFA evidenced peripheral capillary non-perfusion (Fig. 1) that agreed with Stage 2, BCVA 0.04-1.2 (0.59±0.32). Twenty-one eyes (21/42) with neovascularization peripherally at the posterior edge of the non-perfusion, one eye with macular and two eyes with papillary neovascularization and/or VH reached Stage 3, BCVA 0.01-1.5 (0.57±0.33). One eye (1/42) had NVG at Stage 5 (BCVA 0.05) although scattered photocoagulation was performed before the patient came to the authors. The staging of the eyes is illustrated in Table 3.Two eyes (2/42) (BCVA 0.02 and LP respectively) had an obscuring view of the fundus and B-ultrasound scanning revealed a whole RD 2-4mm in the LP eye, with severe PVR in both eyes. These two eyes did not agree with any stages suggested by Samuel et al [2] (see Table 1).
Laser photocoagulation of non-perfusion areas were intended to be performed in eyes only with capillary non-perfusion of stage 2. Pan-retinal photocoagulation (PRP) for stage 3 or more severe eyes was indicated. Direct photocoagulation of the aneurysms was forbidden. For younger patients with obvious vessel leakage elucidated by FFA, oral corticosteroid was prescribed according to the doctor’s judgment. With heavy VH and PVR or if the VH developed and did not resolved within at least two weeks at the initial visit or during the follow-up period, PPV was performed according to the clinical manifestation and doctor’s consideration.
Retinal photocoagulations were performed by several doctors including doctors of other hospitals. Ten eyes (10/18) received photocoagulation of the non-perfusion areas only (Figure 2) and pan-retinal photocoagulations (PRP) were fulfilled in 8 eyes of stage 2 (8/18) finally (Figure 3). Nineteen eyes (19/21) of stage 3 accepted PRP. Two VH eyes of stage 3 and 1 PVR eye were indicated to PPV at the first visit and had PRP during the operation. Patient 4, with whole RD of the left eye, refused to accept any operation. Seven eyes had recurrent VH during or after photocoagulation, 4 eyes recovered spontaneously, 3 eyes with heavy VH received PPV. Among them, case 3 had PRP completed in both eyes but her left eye had fog-like blurred vision now and then due to VH and when the recurrent VH decreased the vison to 0.5 and persisted for 2 weeks, PPV was performed for the eye. The vision recovered to 1.0 and VH then did not appear till the last visit.
Overall, 34 eyes accepted retinal photocoagulation, 27 eyes completed PRP. Three eyes developed to Stage 3 from Stage 2. One eye of Stage 3 developed to PDR with retinal detachment, which had not been classified in any of the stage by Samuel et al [2] system. PPV was performed for 3 eyes at the first visit due to VH or PVR. Additional 5 eyes, 3 heavy VH, 1 PVR and 1 macular epiretinal membrane eye, received PPV during the follow-up (Table 2).
The BCVA was NLP~1.2 (mean decimal 0.53±0.38) at the last visit. There was no significant change in BCVA between the initial and last visit of the patients. The final mean decimal BCVA of Stage 2 and Stage 3 eyes was 0.58±0.33 and 0.55±0.41 respectively. There was no significant difference between the initial and the final vision either (Table 3).
Severe visual impairment (BCVA≤0.1) was estimated and found in 7 eyes (7/42) (Table 4). One eye (lost follow-up) was found at the first visit due to NVG. Three eyes experienced RD or/and PVR (among them 2 eyes had no light perception at the last visit) and 2 eyes due to exudative maculopathy with dense macular lesion and 1 eye had macular atrophy due to acute macular neuroretinopathy (AMN) which was 0.4 at baseline and 0.05 at the last visit.
Special Fundus Findings and Evolution
Aneurysms on optic disc head and artery bifurcations
Forty-one eyes of twenty-one patients were found aneurysms on the optic disc head and artery bifurcations at the baseline which were illustrated more clearly with FFA. During the follow-up visits, aneurysms on the optic nerve head and artery bifurcations disappeared in eight eyes of four patients (Figure 3). The aneurysms were found decreased in number and size in both eyes in one case. The shortest time observed for this phenomenon was one year. All these patients had received laser photocoagulations. However there was no significant difference in BCVA between the initial and last visit in these eyes (Table 3).
Intra-Retinal Microvascular Abnormality (IRMA)
IRMA was found in the macular area, or nearby, in 7 eyes (Figure 3). Macular neovascularization was also found in the right eye of case 14. One eye with IRMA developed macular neovascularization in the later visit. IRMA was not found to retreat in any of the eyes during the follow-up time. No significant difference was found in BCVA between IRMA group and non-IRMA group, neither between the initial and last visit in eyes with IRMA (Table 3).
Venous abnormality
Thirty eyes of15 patients demonstrated mild to moderate venous fluorescein leakage either as segmented on the main branch of veins and/or peripheral venules at the first visit. Fluorescein leakage usually disappeared after photocoagulation in all the patients at the last visit.
Exudates, edema of maculae and exudative maculopathy
Exudates were found in 28 eyes at the first visit. The exudate varied in amount from several dots or radiant stars to heavy yellow exudates and as well as in area from peri-papillary or involved the macular area. Massive macular and foveal exudates with macular edema were found in 2 eyes of 2 cases and dense ovoid lesions developed in these heavily exudate eyes and eventually led to severe damage to vision due to maculopathy (BCVA≤0.1) (2/42). The exudates of other eyes reduced gradually during the observation period.
Exudates did not found in the posterior area of 11 eyes of 7 patients; unknown in three eyes because VH or PVR meant that fundus could not been seen. One patient had obvious exudates in the right eye, while the left eye had no exudates at all (Figure 3).
Macular epiretinal membrane maculae
Macular epiretinal membrane developed in 8 eyes (8/42) during the follow-up and one eye was operated on.
AMN
AMN developed four months after the diagnosis in the left eye of case 18 (1/42), a female patient less than 40 year- old. The FFA demonstrated a delay of a ciliary artery perfusion with a corresponding macular triangular edema. OCT illustrated a macular nasal edema and hyper-reflective band involved the deeper layers of inner retina at the same time and local retina hypertrophy 4 months later. The vision significantly decreased from 0.4 at the first visit to 0.05 at the last visit.